Caribbean - Central America Weather

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AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
156 PM AST MON NOV 9 2015

.SYNOPSIS...WEAK UPPER LEVEL TROUGH WILL REMAIN OVER THE CENTRAL
CARIBBEAN DURING THE FEW DAYS. STRONG HIGH PRESSURE EMERGING OVER THE
EASTERN UNITED STATES SEABOARD WILL MOVE INTO THE CENTRAL ATLANTIC
BY WEDNESDAY. TROPICAL WAVE OVER THE MONA PASSAGE WILL MOVE
WESTWARD AWAY FROM THE LOCAL ISLANDS TONIGHT.

&&

.DISCUSSION...A TROPICAL WAVE OVER EASTERN HISPANIOLA THIS
AFTERNOON WILL CONTINUE TO MOVE WESTWARD AND AWAY FROM THE LOCAL
ISLANDS TONIGHT. SHOWERS AND THUNDERSTORMS ASSOCIATED WITH THE
WAVE PERSISTED ACROSS THE OFFSHORE CARIBBEAN WATERS DURING THE
MORNING AND EARLY THIS AFTERNOON. AS THE WAVE MOVES FURTHER
WESTWARD...THE LINGERING MOISTURE WILL COMBINE WITH DAYTIME
HEATING AND LOCAL EFFECTS TO INDUCE SOME AFTERNOON CONVECTION OVER
WESTERN AND INTERIOR PUERTO RICO FOR THE REST OF THE AFTERNOON
HOURS. HOWEVER...GFS MODEL GUIDANCE SUGGESTS THAT A DRY TREND WILL
ENCOMPASS THE REGION BY TUESDAY WITH PWAT VALUES DECREASING TO
NEAR OR SLIGHTLY ABOVE 1.50 INCHES. THIS MOSTLY DRY WEATHER
PATTERN WILL REMAIN ACROSS THE REGION THROUGH THE UPCOMING
WEEKEND. HOWEVER...FOR THOSE DAYS THE LIMITED AVAILABLE MOISTURE
WILL INDUCE THE DEVELOPMENT OF SOME SHOWERS OVER EASTERN SECTIONS
OF PUERTO RICO DURING THE MORNING AND OVERNIGHT HOURS AND ACROSS
WESTERN AND INTERIOR PUERTO RICO EACH AFTERNOON. NOT SIGNIFICANT
WEATHER EVENT IS EXPECTED OVER THE FORECAST AREA IN THE FORESEE
FUTURE.

&&

.AVIATION...MAINLY VFR CONDITIONS EXPECTED ACROSS MOST OF THE
LOCAL FLYING AREA DURING THE FORECAST PERIOD. SHRA/TSRA ARE
FORECAST IN AND AROUND TJMZ AND TJBQ UNTIL 9/21Z...RESULTING IN
PSBL TEMPO MVFR CONDITIONS AND MOUNTAIN OBSCURATIONS OVER WESTERN
PR. LATEST TJSJ 12Z SOUNDING INDICATED AND EASTERLY WIND FLOW UP
TO 25 KNOTS ALL THE WAY FROM THE SURFACE TO 30K FEET...LIGHT AND
VARIABLE ALOFT.

&&

.MARINE...SEAS WILL DIMINISH THROUGH SATURDAY NIGHT. SMALL CRAFT
ADVISORY FOR THE OUTER ATLANTIC WATERS WILL CONTINUE IN EFFECT
UNTIL AT LEAST THIS EVENING.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 78 89 79 90 / 50 50 60 40
STT 77 88 78 88 / 30 40 50 30

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AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
510 AM AST TUE NOV 10 2015

.SYNOPSIS...A MID LEVEL RIDGE BUILDING OVER THE ATLANTIC OCEAN
WILL BECOME THE DOMINANT WEATHER FEATURE. A SURGE OF LOW LEVEL
MOISTURE WILL CONTINUE TO EXIST THE LOCAL AREA EARLY THIS MORNING.
A DRIER AIR MASS IS EXPECTED TO MOVE ACROSS THE REGION DURING THE
NEXT FEW DAYS.

&&

.DISCUSSION...THE DOPPLER RADAR DETECTED FREQUENT PASSING SHOWERS
ACROSS THE EASTERN HALF OF PUERTO RICO AND THE US VIRGIN ISLANDS.
SINCE MIDNIGHT...THE RAINFALL ACCUMULATION OBSERVED AT SOME OF
THE LOCAL RAINGAGES WERE BETWEEN 0.33 INCHES...AT THE LUIS MUNOZ
MARIN AIRPORT...AND AROUND 1.33 INCHES AT THE SAN LORENZO
STATION. ON THE OTHER HAND...TRACES WERE REPORTED AT THE US
VIRGIN ISLANDS RAINGAGES. AS THIS SURGE OF MOISTURE EXIT THE
AREA...A DRIER AIR MASS IS EXPECTED TO ENTER THE LOCAL ISLANDS
THIS MORNING. AS A RESULT...SHOWER ACTIVITY IS EXPECTED TO
DECREASE AS THE DAY PROGRESSES. HOWEVER...THE AVAILABLE MOISTURE
WILL COMBINE WITH THE LOCAL EFFECTS TO PRODUCE SCATTERED SHOWERS
AND ISOLATED THUNDERSTORMS ACROSS THE WESTERN SECTIONS OF PUERTO
RICO DURING THE AFTERNOON HOURS.

MODEL GUIDANCE CONTINUE TO SUGGEST A DRYING AND STABLE TREND
DURING THE NEXT FEW DAYS...WITH DECREASING PRECIPITABLE
WATER...BELOW 2 INCHES...AND MODERATE MID/LOW LEVEL LAPSE
RATES...AROUND 5C/KM. IN ADDITION...THE TRADE WINDS ARE EXPECTED
TO BECOME LIGHT/MODERATE AFTER MID-WEEK AS THE SURFACE HIGH
PRESSURE LIFTS FARTHER NORTH ACROSS THE ATLANTIC...AND THE LOCAL
PRESSURE GRADIENT RELAXES. HOWEVER...THE TYPICAL PASSING
OVERNIGHT AND EARLY MORNING SHOWERS...FOLLOWED BY DIURNALLY
INDUCED AFTERNOON CONVECTION MAINLY ACROSS PARTS OF THE INTERIOR
AND WEST SECTIONS OF PUERTO RICO ARE EXPECTED EACH DAY.

&&

.AVIATION...MAINLY VFR CONDS EXPECTED ACROSS MOST OF THE TERMINALS
THRU THE FCST PERIOD. HOWEVER...SHRA/TSRA ARE FORECAST IN AND AROUND
TJMZ AND TJBQ BTW 10/17Z-21Z...RESULTING IN PSBL TEMPO MVFR CONDS
AND MOUNTAIN OBSCURATIONS OVER WESTERN PR. LOW LEVEL WINDS WILL BE
FM THE E-ESE AT 15-25 KT.

&&

.MARINE...SMALL CRAFT OPERATORS SHOULD EXERCISE CAUTION ACROSS
MOST OF THE LOCAL WATERS DUE TO CHOPPY SEAS BETWEEN 4 AND 6 FEET
AND WINDS OF 10-15 KNOTS OCCASIONALLY UP TO 20 KNOTS. THE WINDS
ARE EXPECTED TO BECOME LIGHT AND MODERATE AFTER WEDNESDAY. A
NORTHERLY SWELL IS EXPECTED TO REACH THE LOCAL WATERS BY THE
WEEKEND.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 77 90 77 / 30 50 20 50
STT 88 79 88 77 / 20 50 20 50

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AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
152 PM AST TUE NOV 10 2015

.SYNOPSIS...WEAK UPPER LEVEL TROUGH DISSIPATING OVER THE CENTRAL
CARIBBEAN. A MID TO UPPER LEVEL RIDGE OVER THE ATLANTIC WILL
REMAIN AS THE DOMINANT WEATHER FEATURE...MAINTAINING A DRIER AIR
MASS OVER THE REGION UNTIL THE UPCOMING WEEKEND.

&&

.DISCUSSION...THE DOPPLER WEATHER RADAR INDICATED SCATTERED
SHOWERS ACROSS EASTERN AND CENTRAL SECTIONS OF PUERTO RICO THIS
AFTERNOON. THIS ACTIVITY WAS ASSOCIATED WITH A SURGE OF LOW LEVEL
MOISTURE MOVING ACROSS THE REGION TODAY. MODEL GUIDANCE CONTINUE
TO SUGGEST A DRYING AND STABLE TREND FOR THE NEXT SEVERAL
DAYS...WITH PWAT VALUES DECREASING TO NEAR OR SLIGHTLY ABOVE 1.50
INCHES. THUS MOSTLY DRY WEATHER PATTERN WILL REMAIN ACROSS THE
REGION THROUGH THE UPCOMING WEEKEND. HOWEVER...FOR THOSE DAYS THE
TRADE WINDS FLOW ACROSS THE REGION...WILL INDUCE THE DEVELOPMENT
OF TYPICAL PASSING SHOWERS OVER EASTERN SECTIONS OF PUERTO RICO
DURING THE MORNING AND OVERNIGHT HOURS AND ACROSS WESTERN AND
INTERIOR PUERTO RICO EACH AFTERNOON. NOT SIGNIFICANT WEATHER EVENT
IS EXPECTED OVER THE FORECAST AREA IN THE FORESEE FUTURE.

&&

.AVIATION...MAINLY VFR CONDITIONS EXPECTED ACROSS MOST OF THE
TERMINALS THRU THE FCST PERIOD. HOWEVER...SHRA/TSRA ARE FORECAST
IN AND AROUND TJMZ AND TJBQ...RESULTING IN PSBL TEMPO MVFR
CONDITIONS AND MOUNTAIN OBSCURATIONS OVER WESTERN PR UNTIL 10/22Z.
LEVEL WINDS WILL BE FM THE E-ESE AT 15-25 KT.

&&

.MARINE...SEAS UP TO 6 FEET AND WINDS UP TO 20 KNOTS ARE EXPECTED
OVERNIGHT AND THEREFORE...SMALL CRAFT ARE URGED TO EXERCISE
CAUTION MOST OF THE LOCAL WATERS.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 77 90 77 88 / 50 20 50 10
STT 79 88 77 87 / 50 20 50 20

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AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
452 AM AST WED NOV 11 2015

.SYNOPSIS...WEAK TUTT CONTINUES OVER THE CENTRAL CARIBBEAN INTO
THE EASTERN CARIBBEAN SEA WHILE MID LEVEL RIDGE DOMINATES THE
ATLANTIC/EASTERN CARIBBEAN SIDE. AT LOWER LEVELS...EASTERLY WAVE
WILL CONTINUE MOVING WEST WELL SOUTH OF THE ISLANDS TODAY. TRADE
WIND PATTERN WILL ESTABLISH THRU THE END OF THE WEEK.


&&

.DISCUSSION...CLEAR TO PARTLY CLODY SKIES PREVAILED OVERNIGHT ACROSS
THE LOCAL ISLANDS...WITH PASSING TRADE WIND SHOWERS OBSERVED
MAINLY OVER THE WATERS WITH SOME AFFECTING ISOLATED AREAS OF
EASTERN PR AND THE USVI. RAINFALL AMOUNTS WERE NOT SIGNIFICANT.
HIGH LEVEL CLOUDS FILTERED ACROSS THE FORECAST AREA FROM
THUNDERSTORMS OVER THE CARIBBEAN SEA DUE TO THE INTERACTION OF
THE TUTT AND EASTERLY WAVE. FOR THE REST OF THE MORNING HOURS
EXPECT A FEW SHOWERS EMBEDDED ON THE EASTERLIES TO AFFECT THE USVI
AND THE EASTERN COASTAL SECTIONS OF PR...FOLLOWED BY LIMITED AFTERNOON
CONVECTION OVER SECTIONS OF NORTHWESTERN PR AND POSSIBLE SHOWERS
STREAMING OF EL YUNQUE RAIN FOREST AND AFFECTING THE SAN JUAN
METRO AREA.

ON THURSDAY...MODEL GUIDANCE SUGGEST A DRIER AIR MASS FILTERING
OVER THE ISLANDS WITH A NORTHEAST WIND FLOW...LIMITING AFTERNOON
CONVECTION...IF ANY...OVER THE SOUTHWESTERN COAST OF PR. THEN
TRADE WIND SHOWER PATTERN SHOULD CONTINUE DURING THE NIGHT
TIME/EARLY MORNING PERIOD AND AFTERNOON CONVECTION INDUCED BY
DAYTIME HEATING AND OROGRAPHIC EFFECTS OVER THE WESTERN SIDE OF
THE ISLAND THRU AT LEAST THE WEEKEND.


&&

.AVIATION...VFR CONDS EXPECTED AT ALL TAF SITES WITH VCSH POSSIBLE
AT JSJ/IST/ISX AND LEEWARD TERMINALS EARLY THIS MORNING. AFT 11/16Z
SHRA/TSRA DEVELOPING OVER W AND NW PR...AND MAY CAUSE MVFR CONDS AND
MOUNTAIN OBSCURATIONS IN AND AROUND JBQ/JMZ THROUGH 11/22Z. LOW
LEVEL WINDS E-ESE AT 15-20 KT WITH SOME SEE BREEZE VARIATIONS.


&&

.MARINE...SMALL CRAFTS SHOULD CONTINUE TO EXERCISE CAUTION ACROSS
THE OFFSHORE WATERS AND CARIBBEAN PASSAGES AS SEAS UP TO 6 FEET
AND EAST WINDS BETWEEN 15-20 KNOTS ARE EXPECTED TODAY. THERE IS A
MODERATE RISK OF RIP CURRENTS MAINLY ACROSS THE NORTHWESTERN COAST
OF PR AND AT CRAMER PARK IN ST. CROIX. SEAS WILL CONTINUE TO
GRADUALLY SUBSIDE AND STAY BETWEEN 2-5 FEET THROUGH THE END OF THE
WEEK.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 90 76 89 76 / 20 50 10 20
STT 87 76 87 77 / 20 50 10 30

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
246 PM AST WED NOV 11 2015

.SYNOPSIS...WEAK TUTT CONTINUES OVER THE CENTRAL CARIBBEAN INTO
THE EASTERN CARIBBEAN SEA WHILE MID LEVEL RIDGE DOMINATES THE
ATLANTIC/EASTERN CARIBBEAN SIDE. AT THE SURFACE...HIGH PRESSURE
WILL CONTINUE TO PRODUCE MODERATE TRADE WINDS ACROSS THE LOCAL
REGION THROUGH THE REST OF THE WEEK.

&&

.DISCUSSION...PARTLY TO MOSTLY SUNNY SKIES PREVAILED ACROSS PUERTO
RICO AND THE U.S. VIRGIN ISLANDS TODAY. SOME LIGHT PASSING SHOWERS
WERE NOTED MAINLY OVER THE COASTAL WATERS. THIS
AFTERNOON...SHOWERS WITH ISOLATED THUNDERSTORMS DEVELOPED WEST OF
THE SAN JUAN METROPOLITAN AREA. REST OF PUERTO RICO WAS RAIN FREE.
FOR THE REST OF THIS AFTERNOON SHOWERS AND POSSIBLE ISOLATED
THUNDERSTORMS ARE EXPECTED TO DEVELOP OVER THE WESTERN INTERIOR
AND NORTHWEST SECTIONS OF PUERTO RICO. HOWEVER...EVERYTHING THAT
DEVELOPS WILL DISSIPATED NEAR SUNSET.

FOR THE NEXT FEW DAYS...TRADE WINDS WILL BRING PASSING SHOWERS
ACROSS THE LOCAL REGION FROM TIME TO TIME. WEAK TUTT WILL
CONTINUE OVER THE CENTRAL CARIBBEAN INTO THE EASTERN CARIBBEAN
SEA WHILE MID LEVEL RIDGE DOMINATES THE ATLANTIC/CARIBBEAN SIDE.
AT THE SURFACE...HIGH PRESSURE WILL CONTINUE TO DOMINATE THE
REGION. THEREFORE...DRY WEATHER CONDITIONS ARE EXPECTED TO PREVAIL
ACROSS THE LOCAL REGION THROUGH THE WEEKEND. AT THIS TIME...NO
SIGNIFICANT WEATHER EVENTS ARE FORECAST TO AFFECT THE REGION IN
THE LONG TERM.

&&

.AVIATION...VFR CONDS EXPECTED AT ALL TAF SITES WITH VCSH POSSIBLE
AT JSJ/IST/TNCM/TKPK AND SHRA/TSRA DEVELOPING OVER W AND NW
PR...AND MAY CAUSE MVFR CONDS AND MOUNTAIN OBSCURATIONS IN AND
AROUND JBQ/JMZ THROUGH 11/22Z. AFTERNOON CONVECTION IS EXPECTED
TO ENDS AFT 11/22Z...THEN PASSING/VCSH ARE EXPECTED MAINLY ACROSS
TJSJ/TIST/TISX/TKPK/TNCM OVERNIGHT. E-ESE WINDS AT 10-20 KTS WITH
SEA BREEZE VARIATION AND HIGHER GUSTS IN/NEAR SHRA/TSRA...TURNING
CALM TO LIGHT AND VARIABLE AFT 11/22Z.

&&

.MARINE...SEAS UP TO 6 FEET AND WINDS UP TO 15 KNOTS ARE EXPECTED
OVER THE COASTAL WATERS. SMALL CRAFT SHOULD EXERCISE CAUTION
ACROSS THE OFFSHORE ATLANTIC WATERS AND ACROSS THE MONA PASSAGE.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 76 89 76 88 / 50 10 20 20
STT 76 87 77 87 / 50 10 30 30

&&

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
448 AM AST THU NOV 12 2015

.SYNOPSIS...MID LEVEL RIDGE WILL CONTINUE TO PERSIST ACROSS
THE FORECAST AREA THROUGH EARLY NEXT WEEK. THIS FEATURE WILL
WEAKEN MONDAY AND TUESDAY...AS A MID TO UPPER LEVEL TROUGH AND
ASSOCIATED INDUCED SURFACE LOW DEVELOP ACROSS THE SOUTHWEST
ATLANTIC AND NORTH CENTRAL CARIBBEAN. A MODERATE EASTERLY WIND
FLOW WILL PREVAIL THROUGH MONDAY...BECOMING SOUTHERLY AND
FRESH TO LOCALLY STRONG BY MIDWEEK.


&&

.DISCUSSION...MOSTLY CLEAR TO PARTLY CLOUDY SKIES PREVAILED
ACROSS THE LOCAL ISLANDS DURING THE OVERNIGHT AND EARLY MORNING
HOURS. ISOLATED TO SCATTERED PASSING SHOWERS WERE OBSERVED ACROSS
THE LOCAL WATERS...WITH SOME OF AFFECTING THE NORTH AND EAST
COASTAL ARES OF THE LOCAL ISLANDS. RAINFALL ACCUMULATIONS
ASSOCIATED WITH THIS ACTIVITY WERE MINIMAL. WINDS WERE EASTERLY AT
10 MPH OR LESS WITH COASTAL TEMPERATURES IN THE MID TO UPPER 70S.

A MID LEVEL RIDGE PATTERN...NEAR NORMAL PRECIPITABLE WATER AND A
MODERATE EASTERLY WIND FLOW WILL PERSIST TODAY THROUGH MONDAY.
THIS PATTERN WILL CONTINUE TO RESULT IN EARLY MORNING PASSING
SHOWERS ACROSS THE EAST AND NORTH COASTAL AREAS...FOLLOWED BY
AFTERNOON SHOWERS AND THUNDERSTORMS ACROSS WEST PUERTO RICO...
WITH TODAY AS THE DRIEST DAY OF THE NEXT FIVE DAYS.

LATEST GUIDANCE SUGGESTS A WET/ACTIVE WEATHER PATTERN BY MIDWEEK
NEXT WEEK...AS THE AFOREMENTIONED MID TO UPPER LEVEL TROUGH AND
ASSOCIATED INDUCED SURFACE LOW DEVELOP ACROSS THE SOUTHWEST
ATLANTIC AND NORTH CENTRAL CARIBBEAN. THIS PATTERN WILL PROMOTE...
FRESH TO LOCALLY STRONG SOUTHERLY WINDS...DEEP MOISTURE ADVECTION
AND FAVORABLE UPPER LEVEL DYNAMICS WEDNESDAY THROUGH THE REST OF
THE WEEK. STAY TUNED TO SEE HOW THIS PATTERN EVOLVES.

&&

.AVIATION...MAINLY VFR ACROSS ALL TERMINALS NEXT 24 HOURS. SHRA
TO DEVELOP OVER WESTERN INTERIOR OF PR BETWEEN 12/17Z-
22Z...IMPACTING MAINLY THE VCNTY OF JMZ/JPS. BRIEF -TSRA COULD
DEVELOP FROM THESE SHOWERS BUT CONFIDENCE LOW ATTM. LOW LEVEL
WINDS FM THE ENE-E AT 5- 15 KT...WINDS SHIFTING TO E-ESE AFT
13/00Z.

&&

.MARINE...SEAS OF 3-5 FEET ACROSS LOCAL WATERS OF PUERTO RICO AND
THE U.S. VIRGIN ISLANDS. MARINE CONDS WILL REMAIN SIMILAR THROUGH
SATURDAY. THEN...NNE SWELL OF 4-6 FT IS FORECAST TO REACH THE
LOCAL ATLANTIC WATERS AND CARIBBEAN PASSAGES.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 77 87 76 / 10 20 20 40
STT 86 79 86 78 / 10 40 40 40

&&

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
329 PM AST THU NOV 12 2015

.SYNOPSIS...A MID LEVEL RIDGE WILL CONTINUE TO PERSIST ACROSS
THE FORECAST AREA THROUGH EARLY NEXT WEEK. THIS FEATURE WILL DRIFT
EASTWARD AND WILL WEAKEN EARLY NEXT WEEK...AS A MID TO UPPER
LEVEL TROUGH AND ASSOCIATED INDUCED SURFACE LOW DEVELOP ACROSS THE
SOUTHWEST ATLANTIC AND NORTH CENTRAL CARIBBEAN. A MODERATE
EASTERLY WIND FLOW WILL PREVAIL THROUGH MONDAY...BECOMING
SOUTHERLY AND FRESH TO LOCALLY STRONG BY THE UPCOMING MIDWEEK.

&&

.DISCUSSION...MOSTLY SUNNY SKIES PREVAILED TODAY ACROSS THE LOCAL
ISLANDS DURING THE MORNING AND EARLY AFTERNOON HOURS. CLOUDINESS
BEGAN TO INCREASE ALONG THE CENTRAL MOUNTAIN RANGE AND OVER THE
SOUTHERN SLOPES DURING THE AFTERNOON BUT NO SIGNIFICANT RAINFALL
HAS BEEN OBSERVED AT THIS MOMENT. MIMIC TPW IMAGES DETECTED A DRY
AIR MASS OVER THE ISLANDS...AS WAS OBSERVED WITH TJSJ SOUNDING
DATA...WHICH SHOWED A TPW VALUE OF 1.28 IN. HOWEVER...THE
AVAILABLE MOISTURE COMBINED WITH THE LOCAL EFFECTS CAN PRODUCE
SOME SHOWERS MAINLY ACROSS THE INTERIOR AND SOUTHWESTERN PR. NO
SIGNIFICANT RAINFALL EVENT IS EXPECTED AT THIS TIME.

A MID LEVEL RIDGE PATTERN...NEAR NORMAL PRECIPITABLE WATER AND A
MODERATE EASTERLY WIND FLOW WILL PERSIST TONIGHT THROUGH MONDAY.
THIS PATTERN WILL RESULT IN THE TYPICAL OVERNIGHT AND EARLY
MORNING PASSING SHOWERS ACROSS THE EAST AND NORTH COASTAL
AREAS...FOLLOWED BY AFTERNOON SHOWERS AND THUNDERSTORMS ACROSS
THE MUNICIPALITIES OF THE INTERIOR AND WESTERN PUERTO RICO FOR THE
NEXT FIVE DAYS.

&&

.AVIATION...MAINLY VFR ACROSS ALL TERMINALS NEXT 24 HOURS. SHRA
TO DEVELOP OVER WESTERN INTERIOR OF PR BETWEEN 12/17Z-
22Z...IMPACTING MAINLY THE VCNTY OF JMZ/JPS. LOW LEVEL WINDS FM
THE ENE-E AT 5-15 KT...WINDS SHIFTING TO E-ESE AFT 13/00Z.

&&

.MARINE...SEAS OF LESS THAN 5 FEET ACROSS LOCAL WATERS OF PUERTO
RICO AND THE U.S. VIRGIN ISLANDS. MARINE CONDS WILL REMAIN SIMILAR
THROUGH SATURDAY. THEN...NNE SWELL OF 4-6 FT IS FORECAST TO REACH
THE LOCAL ATLANTIC WATERS AND CARIBBEAN PASSAGES.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 76 88 76 87 / 20 20 40 40
STT 76 88 77 86 / 40 40 40 40

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
450 AM AST FRI NOV 13 2015

.SYNOPSIS...MID TO UPPER LEVEL RIDGE WILL PERSIST ACROSS THE FORECAST
AREA TODAY. THE RIDGE ALOFT WILL GRADUALLY ERODE OVER THE WEEKEND AND
INTO EARLY NEXT WEEK...AS A SHORT WAVE TROUGH WILL PROPAGATE EASTWARD
ACROSS THE SOUTHWEST ATLANTIC. THIS FEATURE WILL SUPPORT THE
AMPLIFICATIONOF A POLAR TROUGH FORECAST TO ENTER THE
NORTHWESTERN ATLANTIC BY SUNDAY AND MONDAY. IN THE LOW LEVELS...A
WEAK RIDGE OF HIGH PRESSURE STRETCHED ACROSS THE SUB- TROPICAL
ATLANTIC WILL MAINTAIN LIGHT TO MODERATE EASTERLY TRADE WINDS
THROUGH THE WEEKEND. THE SURFACE RIDGE IS TO SLOWLY REESTABLISHES
NORTH OF THE AREA BY SUNDAY AND INTO EARLY NEXT WEAK...AS IT WILL
BE REINFORCED BY ANOTHER AREA OF HIGH PRESSURE FORECAST TO ENTER
THE WESTERN ATLANTIC.

&&

.DISCUSSION...LIGHT TO MODERATE EAST TO NORTHEAST TRADE WINDS WILL
CONTINUE TO BRING OCCASIONAL SURGES OF SHALLOW MOISTURE ACROSS THE
NORTHEASTERN CARIBBEAN OVER THE NEXT FEW DAYS. THIS WILL LEAD TO
PERIODS OF PASSING EARLY MORNING SHOWERS WHICH WILL AFFECT PORTIONS
OF THE NORTH AND EAST COASTAL SECTIONS OF THE ISLANDS FROM TIME TO
TIME. SUFFICIENT AMOUNTS OF MOISTURE ADVECTION ACROSS THE REGION TODAY
ALONG WITH DAYTIME HEATING WILL ALLOW FOR AFTERNOON CONVECTION IN
SOME AREAS. THIS WILL BE FOCUSED MAINLY OVER PORTIONS OF THE INTERIOR
AND THE WEST SECTIONS OF PUERTO RICO. ISOLATED AFTERNOON SHOWERS WILL
ALSO REMAIN POSSIBLE OVER PORTION OF THE U.S. VIRGIN ISLANDS AS WELL
AS THE ADJACENT ISLANDS WHERE SOME MAY FORM AND QUICKLY STREAM ACROSS
THOSE AREAS. SO FAR THE PRESENT WEATHER PATTERN AND LATEST MODEL
GUIDANCE BOTH SUGGEST...NO WIDESPREAD RAINFALL ACROSS THE FORECAST
AREA TODAY AND FOR THE UPCOMING WEEKEND.

BY NEXT WEEK HOWEVER...LATEST GFS MODEL GUIDANCE CONTINUED TO SUGGEST
A WETTER WEATHER PATTERN TO UNFOLD WITH THE AMPLIFICATION OF THE UPPER
TROUGH ACROSS THE WEST AND SOUTHWESTERN ATLANTIC...AND EROSION OF THE
RIDGE ALOFT. MODELS ALSO SUGGEST INCREASING PRECIPITABLE WATER AMOUNTS
BEGINNING EARLY NEXT WEEK...WITH GOOD POOLING OF MOISTURE ACROSS THE
REGION BY THE LATTER PART OF NEXT WEEK...AS A FRONTAL BOUNDARY IS TO
SINK SOUTHWARDS ACROSS THE FORECAST AREA...AND FAVORABLE CONDITIONS
FOR HEAVY RAINS UNFOLD IN THE UPPER LEVELS. THIS IS HOWEVER STILL
SEVERAL DAYS OUT SO WILL CONTINUE TO MONITOR AND ALLOW TIME FOR THE
MODEL GUIDANCE TO ADJUST AND BECOME MORE CONSISTENT.

&&

.AVIATION...BRIEF PERIODS OF MVFR CONDITIONS WILL CONTINUE TO AFFECT
TIST...TISX AND TJSJ UNTIL 13/15Z. VICINITY SHOWERS EXPECTED ELSEWHERE
ACROSS THE LOCAL FLYING AREA/. SHRA/TSRA ARE EXPECTED TO DEVELOP
AFTER 13/17Z...INDUCING BRIEF PERIODS OF MVFR/IFR ACROSS TJMZ AND
TJBQ UNTIL 13/22 WITH MOUNTAIN OBSCURATIONS. TJSJ SOUNDING INDICATED
AND EASTERLY WIND FLOW UP TO 20 KNOTS ALL THE WAY FROM THE SURFACE
TO 32K FEET...BECOMING LIGHT AND VARIABLE ALOFT.

&&

.MARINE...SEAS OF 2 TO 5 FEET AND WINDS OF 10 TO 15 KNOTS CAN BE
EXPECTED ACROSS REGIONAL WATERS OF PUERTO RICO AND THE U.S. VIRGIN
ISLANDS TODAY. MARINE CONDS WILL REMAIN SIMILAR THROUGH SATURDAY.
THEREAFTER...A N-NE SWELL OF 4-6 FT IS FORECAST TO ARRIVE AND SPREAD
ACROSS THE LOCAL ATLANTIC WATERS AND CARIBBEAN PASSAGES ON SUNDAY AND
INTO EARLY NEXT WEEK. BY THEN PRECAUTIONARY STATEMENTS AND SMALL
CRAFT ADVISORIES MAY BE REQUIRED FOR SOME AREAS. STAY TUNED.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 76 88 76 / 30 40 40 20
STT 88 78 87 77 / 40 40 40 30

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
253 PM AST FRI NOV 13 2015

.SYNOPSIS...A WEAK UPPER LEVEL TROUGH AND A MID LEVEL RIDGE WILL
PERSIST ACROSS THE FORECAST AREA THROUGH EARLY NEXT WEEK. AN UPPER
LEVEL TROUGH WILL THEN ESTABLISH WEST OF THE AREA TUESDAY AND
WEDNESDAY. A GENTLE TO MODERATE EASTERLY TRADE WIND FLOW WILL
CONTINUE TO PREVAIL ACROSS THE AREA THROUGH THE WEEKEND. LOCAL
PRESSURE GRADIENT WILL TIGHTEN NEXT WEEK...AS A SURFACE HIGH
PRESSURE ESTABLISHES NORTH OF THE AREA.

&&

.DISCUSSION...MOSTLY SUNNY TO PARTLY CLOUDY SKIES PREVAILED
ACROSS THE LOCAL ISLANDS DURING THE MORNING HOURS...BECOMING
VARIABLY CLOUDY IN THE AFTERNOON. ISOLATED TO LOCALLY SCATTERED
PASSING SHOWERS WERE OBSERVED ACROSS THE LOCAL WATERS...WITH SOME
OF THEM AFFECTING THE NORTH AND EAST COASTAL ARES OF THE LOCAL
ISLANDS IN THE MORNING HOURS. THEREAFTER...SHOWERS AND ISOLATED
THUNDERSTORMS DEVELOPED ACROSS NORTHWEST PUERTO RICO.

A MID LEVEL RIDGE PATTERN...NEAR NORMAL PRECIPITABLE WATER AND
MODERATE TRADES WILL PERSIST THROUGH EARLY MONDAY. THIS PATTERN
WILL CONTINUE TO RESULT IN EARLY MORNING PASSING SHOWERS ACROSS
THE EAST AND NORTH COASTAL AREAS...FOLLOWED BY AFTERNOON SHOWERS
AND THUNDERSTORMS ACROSS WEST PUERTO RICO. A WETTER WEATHER
PATTERN IS THEN EXPECTED MONDAY AFTERNOON THROUGH AT LEAST
THURSDAY... AS AN UPPER LEVEL TROUGH AND ASSOCIATED INDUCED
SURFACE LOW DEVELOP ACROSS THE SOUTHWEST ATLANTIC AND CENTRAL
CARIBBEAN. THIS PATTERN WILL PROMOTE MOISTURE TO POOL ACROSS THE
AREA AS WELL AS FAVORABLE UPPER LEVEL DYNAMICS. THE EXACT TIMING...
ORGANIZATION AND LOCATION OF CONVECTION IS STILL UNCLEAR... BUT
THERE IS A HIGHER CHANCE FOR SHOWERS AND THUNDERSTORMS EACH DAY.
A SHARP DECREASE IN AVAILABLE MOISTURE IS EXPECTED FRIDAY THROUGH
THE NEXT WEEKEND.

&&

.AVIATION...THIS AFTERNOON...CONVECTION CAUSING AT LEAST VCTS AT
TJMZ AND TJBQ WITH POSSIBLE BRIEF PDS OF -TSRA...MVFR CONDS LIKELY
AT SOME POINT BEFORE 13/22Z...WITH VFR AT TAF OTHER SITES WITH SOME
VCSH. BY EVENING...MAINLY VFR ACROSS ALL TERMINALS FOR NEXT 24 HOURS
WITH SOME VCSH FROM TIME TO TIME. LOW LEVEL WINDS FM THE ENE-E AT 5-
15 KT WITH SOME GUSTS...WINDS SHIFTING TO E-ESE AFT 14/00Z.

&&

.MARINE...SEAS OF 2 TO 5 FEET AND WINDS OF 10 TO 20 KNOTS CAN BE
EXPECTED ACROSS REGIONAL WATERS OF PUERTO RICO AND THE U.S. VIRGIN
ISLANDS TONIGHT. MARINE CONDS WILL REMAIN SIMILAR THROUGH SATURDAY.
THEREAFTER...A N-NE SWELL OF 4-6 FT IS FORECAST TO ARRIVE AND
SPREAD ACROSS THE LOCAL ATLANTIC WATERS AND CARIBBEAN PASSAGES ON
SUNDAY AND INTO EARLY NEXT WEEK.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 77 88 76 88 / 40 40 20 20
STT 78 87 78 87 / 40 40 40 40

&&

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
541 AM AST SAT NOV 14 2015

.SYNOPSIS...MID TO UPPER LEVEL RIDGE WILL CONTINUE TO ERODE OVER
THE WEEKEND AND INTO EARLY NEXT WEEK...AS A SHORT WAVE TROUGH WILL
MOVE EASTWARD ACROSS THE SOUTHWEST ATLANTIC. THIS FEATURE WILL BE
LATER SUPPORTED BY A POLAR TROUGH FORECAST TO ENTER THE NORTHWESTERN
ATLANTIC ON SUNDAY AND MONDAY...THEN ESTABLISH JUST WEST OF THE REGION
ON TUESDAY AND WEDNESDAY. SURFACE HIGH PRESSURE STRETCHED ACROSS THE
ATLANTIC WILL MAINTAIN MODERATE EASTERLY TRADE WINDS THROUGH THE WEEKEND.
THE RIDGE IS TO REESTABLISHES NORTH OF THE AREA ON SUNDAY AND INTO EARLY
NEXT WEEK...AS IT WILL BE REINFORCED BY ANOTHER AREA OF HIGH PRESSURE
FORECAST TO ENTER THE WESTERN ATLANTIC. THIS IN TURN WILL TIGHTEN THE
LOCAL PRESSURE GRADIENT AND INCREASE THE EASTERLY TRADE WINDS.

&&

.DISCUSSION...ONLY A FEW PASSING LIGHT TO MODERATE SHOWERS WERE
OBSERVED OVERNIGHT MOVING OVER THE COASTAL WATERS AND BRUSHING
PORTIONS OF THE ISLANDS FROM TIME TO TIME. EXPECT SHOWERS ACTIVITY
AND CLOUDINESS TO DIMINISH ACROSS THE REGION BY LATE MORNING LEAVING
PARTLY CLOUDY SKIES. DURING THE AFTERNOON...DAYTIME HEATING WILL
ALLOW FOR AFTERNOON CONVECTION IN SOME AREAS. THIS WILL BE FOCUSED
MAINLY OVER PORTIONS OF THE INTERIOR AND THE WEST SECTIONS OF PUERTO
RICO. ISOLATED AFTERNOON SHOWERS WILL ALSO REMAIN POSSIBLE OVER
PORTION OF THE U.S. VIRGIN ISLANDS AS WELL AS THE ADJACENT ISLANDS
WHERE THEY MAY FORM AND QUICKLY STREAM ACROSS THOSE AREAS. SO FAR
THE PRESENT WEATHER PATTERN AND LATEST MODEL GUIDANCE BOTH SUGGEST...
NO WIDESPREAD RAINFALL ACROSS THE FORECAST AREA TODAY AND FOR THE
REMAINDER OF THE WEEKEND.

LATEST GFS MODEL GUIDANCE CONTINUED TO SUGGEST A WETTER WEATHER
PATTERN TO UNFOLD WITH THE AMPLIFICATION OF THE UPPER TROUGH
ACROSS THE SOUTHWESTERN ATLANTIC...AND THE EROSION OF THE RIDGE
ALOFT. MODELS ALSO SUGGEST INCREASING PRECIPITABLE WATER AMOUNTS
BEGINNING EARLY NEXT WEEK. GOOD POOLING OF MOISTURE IS SUGGESTED
ACROSS THE AREA BY THE LATTER PART OF NEXT WEEK...AS A FRONTAL
BOUNDARY IS TO SINK SOUTHWARDS...AND A LOW LEVEL CONVERGENCE ZONE
SETS UP ACROSS THE REGION. REGARDLESS OF WHETHER THIS PATTERN
UNFOLDS OR NOT...SO FAR ALL SUGGEST A BETTER CHANCE FOR MOISTURE
ADVECTION AND UNSTABLE CONDITIONS BY THE LATTER PARTS OF THE THE
UPCOMING WEEK. WILL REMAIN CONSERVATIVE FOR NOW BUT WILL SHOW AN
OVERALL UPWARD TREND IN POTENTIAL FOR SHOWERS AND THUNDERSTORMS
ACROSS THE REGION AND ALLOW TIME FOR THE MODEL GUIDANCE TO ADJUST
AND BECOME MORE CONSISTENT.

&&

.AVIATION...MAINLY VFR ACROSS ALL TERMINALS THRU AT LEAST
14/10Z. A BAND OF MOISTURE WILL APPROACH THE FLYING AREA FROM THE
EAST AFTER 14/12Z...INCREASING THE CHANCES OF SHRA OVER THE LEEWARD
AND USVI TERMINALS AS WELL AS TJSJ. THEN...TSRA WILL DEVELOP IN AND
AROUND TJMZ AND TJBQ BTW 17-21Z. BRIEF MVFR CONDITIONS AND MOUNTAIN
OBSCURATION LIKELY THIS AFTERNOON. LOW LEVEL WINDS WILL PREVAIL
MAINLY FROM THE EAST AT 15-20 KT WITH HIGHER GUST NEAR TSRA.

&&

.MARINE...MARINE CONDITIONS REMAIN UNDER THE INFLUENCE OF MODERATE
TO LOCALLY FRESH TRADE WINDS AND 2 TO 5 FOOT SEAS. SEAS WILL HOWEVER
CONTINUE TO RISE SLIGHTLY LATER TONIGHT ACROSS THE ATLANTIC AND LOCAL
PASSAGES...AS A NORTHELY SWELL WILL ARRIVE...THEN SPREAD ACROSS THE
ATLANTIC WATERS AND LOCAL PASSAGES SUNDAY THROUGH MONDAY. PLEASE
REFER TO THE LATEST COASTAL WATERS FORECAST ISSUED BY WFO SAN JUAN
PR FOR ADDITIONAL INFORMATION AND UPDATES.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 89 76 88 78 / 40 20 20 40
STT 88 78 88 77 / 50 30 30 40

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
303 PM AST SAT NOV 14 2015

.SYNOPSIS...A MID-UPPER LEVEL RIDGE WILL CONTINUES TO DRIFT
EASTWARD INTO THE CENTRAL ATLANTIC OCEAN. A POLAR TROUGH IS
FORECAST TO ENTER THE NORTHWESTERN ATLANTIC ON SUNDAY AND
MONDAY...THEN ESTABLISH JUST WEST OF THE REGION ON TUESDAY AND
WEDNESDAY. THIS UPPER LEVEL TROUGH PATTERN IS EXPECTED TO PERSIST
AT LEAST UNTIL FRIDAY. A SURFACE HIGH PRESSURE IS FORECAST TO EXIT
THE EASTERN U.S. TO MOVE INTO THE WESTERN ATLANTIC OCEAN BY EARLY
NEXT WEEK.

&&

.DISCUSSION...SATELLITE AND DOPPLER RADAR DETECTED CLOUDS AND
SHOWERS ACROSS THE LOCAL AREA TODAY. MOST OF THE SHOWER ACTIVITY
MOVED FAST WITHOUT ANY SIGNIFICANT RAINFALL ACCUMULATION. AS AN
EASTERLY SURFACE PERTURBATION MOVES ACROSS THE REGION TODAY...EXPECT
SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS MAINLY OVER THE
INTERIOR AND WESTERN SECTIONS OF PUERTO RICO UNTIL EVENING HOURS.
ALSO...SOME SHOWERS WILL MOVE OVER THE NORTHERN MUNICIPALITIES OF
PUERTO RICO AS THEY DEVELOP DOWNSTREAM FROM EL YUNQUE. IN
ADDITION...SHOWERS ARE EXPECTED TO FORM DOWNSTREAM FROM ST THOMAS
AND ST CROIX TO AFFECT THE LOCAL WATERS. FOR TONIGHT...LOW LEVEL
MOISTURE IS EXPECTED TO MOVE ACROSS THE AREA TO RESULT IN
OVERNIGHT AND EARLY MORNING SHOWERS ACROSS EASTERN PUERTO RICO AND
THE US VIRGIN ISLANDS.

A MID-UPPER LEVEL RIDGE...NEAR NORMAL PRECIPITABLE WATER AND
MODERATE TRADES WILL PERSIST THROUGH MONDAY MORNING. THIS PATTERN
WILL CONTINUE TO RESULT IN TYPICAL OVERNIGHT AND EARLY MORNING
PASSING SHOWERS ACROSS THE WINDWARD SECTIONS AND THEIR COASTAL
WATERS...FOLLOWED BY AFTERNOON SHOWERS AND THUNDERSTORMS OVER AND
TO THE WEST OF THE CORDILLERA CENTRAL. THE POTENTIAL FOR SHOWERS
AND THUNDERSTORMS IS EXPECTED TO INCREASE DURING MOST OF THE NEXT
WORK WEEK...AS A POLAR TROUGH IS EXPECTED TO MOVE ACROSS THE
ATLANTIC WATERS AND PERSISTS WEST AND SOUTHWEST OF THE FORECAST
AREA. THIS PATTERN WILL PROMOTE MOISTURE TO POOL ACROSS THE AREA
AS WELL AS FAVORABLE UPPER LEVEL DYNAMICS.

&&

.AVIATION...MOSTLY VFR CONDS EXPECTED AT ALL TAF SITES THROUGH
THE FORECAST PERIOD WITH BRIEF MVFR CONDS POSSIBLE IN PASSING
SHOWERS AT JSJ/JBQ AND JMZ THROUGH 14/22Z. LOW LEVEL WINDS
EASTERLY AT 15 TO 20 KNOTS WITH SOME SEA BREEZE VARIATIONS...
BECOMING 10 TO 15 KNOTS OVERNIGHT.

&&

.MARINE...THE LOCAL BUOY NETWORK REPORTED SEAS BELOW 4 FEET AND
WINDS BELOW 18 KT. SEAS WILL HOWEVER CONTINUE TO RISE SLIGHTLY
LATER TONIGHT ACROSS THE ATLANTIC AND LOCAL PASSAGES...AS A
NORTHERLY SWELL WILL ARRIVE...THEN SPREAD ACROSS THE ATLANTIC
WATERS AND LOCAL PASSAGES SUNDAY THROUGH MONDAY. PLEASE REFER TO
THE LATEST COASTAL WATERS FORECAST ISSUED BY WFO SAN JUAN PR FOR
ADDITIONAL INFORMATION AND UPDATES.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 77 88 77 85 / 20 20 40 40
STT 78 88 77 86 / 30 30 40 40

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
601 AM AST SUN NOV 15 2015

.SYNOPSIS...MID TO UPPER LEVEL TROUGH WILL CONTINUE TO MOVE EASTWARD
ACROSS THE REGION TODAY AND REACH THE NORTHERN LEEWARDS ON MONDAY. IN
THE MEANTIME...A POLAR TROUGH WILL ENTER THE NORTHWESTERN ATLANTIC LATER
TODAY...THEN BECOME AMPLIFIED AND SINK SOUTHWARDS TO JUST WEST OF THE
REGION BY TUESDAY AND WEDNESDAY. BY THEN...THE UPPER TROUGH PATTERN
IS FORECAST TO PERSIST AT LEAST UNTIL FRIDAY. SURFACE HIGH PRESSURE
WILL CONTINUE TO EXIT THE EASTERN SEABOARD OF THE UNITED STATES...AND
SPREAD ACROSS THE WESTERN ATLANTIC OVER THE NEXT SEVERAL DAYS. THIS
WILL INCREASE THE EASTERLY TRADE WINDS ACROSS THE REGION AS THE
PRESSURE GRADIENT TIGHTENS.

&&

.DISCUSSION...ONLY A FEW PASSING TRADE WIND SHOWERS WERE NOTED MOVING
WESTWARD ACROSS THE COASTAL WATERS THIS MORNING...WITH LITTLE OR
NO PRECIPITATION REACHING THE COASTAL AREAS SO FAR. EXCEPT FOR THESE
PASSING SHOWERS...SOMEWHAT DRIER CONDITIONS ARE EXPECTED DURING MOST
OF THE DAY AS THE REGION WILL BE ON THE SUBSIDENT SIDE OF THE UPPER
TROUGH. STILL HOWEVER EXPECT DIURNALLY INDUCED AFTERNOON SHOWERS
MAINLY OVER PARTS OF THE INTERIOR AND WEST SECTIONS OF PUERTO RICO.
RECENT SATELLITE IMAGERY SHOWED ANOTHER SURGE OF TRADE WIND MOISTURE
MOVING ACROSS THE NORTHERN LEEWARDS. SOME OF THESE SHOWERS MAY REACH
PARTS OF THE VIRGIN ISLANDS LATER THIS MORNING AND EARLY
AFTERNOON BUT THEY WILL BE MOSTLY LIGHT AND OF SHORT DURATION.

FOR MONDAY AND TUESDAY...EXPECT THE TYPICAL PASSING TRADE WIND SHOWERS
AND MODERATE TRADE WINDS TO PERSIST ACROSS THE REGION. OVERNIGHT
AND EARLY MORNING PASSING SHOWERS...WILL BE FOLLOWED BY DIURNALLY
INDUCED AFTERNOON SHOWERS AND POSSIBLY AN ISOLATED THUNDERSTORM OR
TWO MAINLY OVER PARTS OF THE INTERIOR AND WEST SECTIONS OF PUERTO
RICO.

BY THE MIDDLE OF THE WEEK AND AT LEAST UNTIL FRIDAY...THE POTENTIAL
FOR SHOWERS AND THUNDERSTORMS IS FORECAST TO INCREASE... AS MODELS
CONTINUE TO SUGGEST THAT THE UPPER TROUGH WILL SINK SOUTHWARD AND
LINGER WEST OF THE REGION BY THEN ALONG WITH INCREASING EAST TO
NORTHEAST TRADE WINDS. THIS PATTERN ALONG WITH THE APPROACH OF A
FRONTAL BOUNDARY AND MOISTURE CONVERGENCE ACROSS THE AREA...WILL
FAVOR UPPER LEVEL DYNAMICS AND UNSTABLE WEATHER CONDITIONS. STAY
TUNED...MORE TO COME ON THIS IN THE NEXT FEW DAYS.

&&

.AVIATION...MAINLY VFR CONDITIONS EXPECTED ACROSS ALL TERMINALS FOR
THE NEXT 24 HRS. FOR THE MORNING HOURS...VCSH POSSIBLE FOR TJSJ...TIST
AND TISX...CLEARING AFT 15/14Z. AFTERNOON CONVECTION POSSIBLE...CAUSING
AT LEAST VCTS AT TJMZ AND TJBQ AFTER 15/17Z. POSSIBLE MVFR CONDITIONS
AT TJMZ AS SHRA/TSRA DEVELOPS OVER THE AREA...LIKELY AT SOME POINT
BETWEEN 15/18Z AND 15/22Z. WINDS E-ESE 10 TO 15 KTS WITH HIGHER
GUSTS AFT 15/14Z.

&&

.MARINE...THE LOCAL NEAR SHORE BUOYS REPORTED SEAS BELOW 5 FEET
AND WINDS BELOW 15 KTS OVERNIGHT. SEAS WILL HOWEVER CONTINUE TO
RISE SLIGHTLY AS A SMALL NORTHERLY SWELL WILL ARRIVE AND SPREAD
ACROSS THE ATLANTIC AND LOCAL PASSAGES TODAY AND MONDAY. SMALL
CRAFT OPERATORS SHOULD THEREFORE EXERCISE CAUTION. PLEASE REFER TO
THE LATEST COASTAL WATERS FORECAST ISSUED BY WFO SAN JUAN PR FOR
ADDITIONAL INFORMATION AND UPDATES.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 76 86 75 / 20 40 40 40
STT 88 77 86 77 / 30 40 40 40

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
210 PM AST SUN NOV 15 2015

.SYNOPSIS...AS AN UPPER LEVEL TROUGH ACROSS THE EASTERN CARIBBEAN
WEAKENS...A SHORTWAVE RIDGE WILL BUILD ACROSS THE FORECAST AREA.
HOWEVER...THIS FEATURE WILL QUICKLY ERODE BY TUESDAY AS A MID TO
UPPER LEVEL TROUGH AMPLIFIES ACROSS THE WESTERN ATLANTIC AND THE
CENTRAL CARIBBEAN. A SURFACE HIGH PRESSURE NORTH OF THE AREA WILL
CONTINUE TO PROMOTE EASTERLY WINDS MUCH OF THIS WEEK.

&&

.DISCUSSION...MOSTLY SUNNY TO PARTLY CLOUDY SKIES PREVAILED ACROSS
THE LOCAL ISLANDS TODAY...WITH ISOLATED TO SCATTERED PASSING SHOWERS
OBSERVED ACROSS THE LOCAL WATERS IN THE MORNING HOURS. THEREAFTER...
SHOWERS AND ISOLATED THUNDERSTORMS DEVELOPED OVER WESTERN PUERTO
RICO AS WELL AS TO THE WEST OF USVI...CULEBRA AND VIEQUES IN THE
AFTERNOON. WINDS WERE EASTERLY AT 10 TO 20 MPH AND COASTAL TEMPS
WERE IN THE MID TO UPPER 80S.

UNDER THE INFLUENCE OF A WEAK RIDGE PATTERN...ENOUGH AVAILABLE
MOISTURE AND A MODERATE EASTERLY WIND FLOW...CONTINUE TO EXPECT
PASSING SHOWERS ACROSS THE EAST AND NORTH COASTAL AREAS IN THE
MORNING AND EVENING HOURS...FOLLOWED BY SHOWERS AND THUNDERSTORMS
OVER AND WEST THE CORDILLERA CENTRAL IN THE AFTERNOON MONDAY AND
TUESDAY.

A MID TO UPPER LEVEL TROUGH WILL AMPLIFY ACROSS THE WESTERN
ATLANTIC AND CENTRAL CARIBBEAN TUESDAY AND WEDNESDAY. AT LOWER
LEVELS...A FRONTAL BOUNDARY WILL DISSIPATE NORTH OF THE AREA WITH
A SECOND FRONTAL BOUNDARY REACHING THE LOCAL ISLANDS DURING THE
LATTER PART OF THE WORKWEEK. THIS EXPECTED PATTERN WILL PROMOTE
MOISTURE TO POOL ACROSS THE AREA AS WELL AS FAVORABLE UPPER LEVEL
DYNAMICS LATE TUESDAY THROUGH FRIDAY. AS A RESULT...THERE IS A
HIGHER CHANCE FOR PERIODS OF SHOWERS AND THUNDERSTORMS ACROSS THE
LOCAL ISLANDS EACH DAY. A SHARP DECREASE IN AVAILABLE MOISTURE IS
EXPECTED FRIDAY THROUGH THE WEEKEND.

&&

.AVIATION...MAINLY VFR CONDS EXPECTED ACROSS ALL TERMINALS FOR
THE NEXT 24 HRS. VCSH STILL EXPECTED AT TJSJ...TIST...TISX...
TNCM...TKPK. BRIEF MVFR EXPECTED AT TIST/TISX BTWN 15/18-20Z.
ALSO...MOUNT OBSC AND CONVECTION EXPECTED OVER AND TO THE WEST OF
THE CORDILLERA CENTRAL TO RESULT IN BRIEF MVFR CONDS IN SHRA/TSRA
AT TJMZ BTWN 15/18-21Z...CLEARING AFT 15/23Z WITH JUST VCSH ACROSS
TJSJ/TISX/TIST OVERNIGHT. SFC WINDS FROM THE E-ESE AT 10 TO 15 KTS
WITH HIGHER GUSTS...TURNING CALM TO LIGHT AND VARIABLE AFT 15/23Z.

&&

.MARINE...A NORTHERLY SWELL WILL CONTINUE TO AFFECT THE LOCAL
WATERS THROUGH MONDAY. SEAS UP TO 6 FEET AND WINDS 20 KNOTS OR
LESS ARE EXPECTED. SMALL CRAFT ARE URGED TO EXERCISE CAUTION
ACROSS MOST OF LOCAL WATERS.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 77 86 77 86 / 40 50 30 50
STT 77 86 77 86 / 40 40 50 50

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
523 AM AST MON NOV 16 2015

.SYNOPSIS...AN UPPER LEVEL TROUGH ACROSS THE EASTERN CARIBBEAN
WILL CONTINUE TO MOVE EASTWARD WHILE WEAKENING TODAY AND TONIGHT.
A MID TO UPPER LEVEL TROUGH IS EXPECTED TO AMPLIFY ACROSS THE
WESTERN ATLANTIC AND CENTRAL CARIBBEAN BY MID WEEK AND ACROSS THE
LOCAL REGION THURSDAY AND FRIDAY. THIS FEATURE WILL INDUCE AN
INCREASE IN MOISTURE ACROSS THE LOCAL ISLANDS. A SURFACE HIGH
PRESSURE ACROSS THE EASTERN UNITED STATES SEABOARD WILL CONTINUE
TO PROMOTE AN EASTERN WIND FLOW UNTIL MID WEEK...SHIFTING TO THE
NORTHEAST BY THURSDAY.

&&

.DISCUSSION...DOPPLER WEATHER RADAR DETECTED A SLIGHT INCREASE IN
LOW LEVEL MOISTURE ACROSS THE REGION OVERNIGHT AND EARLY THIS
MORNING. SHOWERS MOVED FROM THE ATLANTIC WATERS ACROSS THE U.S.
VIRGIN ISLANDS...VIEQUES...CULEBRA AND EASTERN PUERTO RICO FROM
TIME TO TIME. THIS MOISTURE IS EXPECTED TO COMBINE WITH DAYTIME
HEATING AND LOCAL EFFECTS THIS AFTERNOON FOR THE DEVELOPMENT OF
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS OVER WESTERN AND
INTERIOR SECTIONS OF PUERTO RICO. AN UPPER LEVEL LOW OVER THE
EASTERN CARIBBEAN WILL MOVE EASTWARD WHILE WEAKENING TODAY AND
TONIGHT. A MID TO UPPER LEVEL TROUGH IS EXPECTED TO AMPLIFY OVER
THE WESTERN ATLANTIC AND CENTRAL CARIBBEAN BY TUESDAY AND
WEDNESDAY. THIS FEATURE WILL THEN AMPLIFY ACROSS THE REGION BY
THURSDAY AND FRIDAY AS A FRONTAL BOUNDARY CROSS THE LOCAL
ISLANDS. THESE FEATURES WILL PRODUCE AND INCREASE IN MOISTURE
WITH PERIODS OF SHOWERS AND THUNDERSTORMS ACROSS THE LOCAL ISLANDS
AND THE SURROUNDING WATERS. A RAPID DECREASE IN MOISTURE IS THEN
EXPECTED BY SATURDAY AND SUNDAY AS THE UPPER TROUGH MOVES TO THE
EAST OF THE REGION AND THE FRONTAL BOUNDARY REMNANT DISSIPATES
ACROSS THE CARIBBEAN WATERS SOUTH OF THE REGION. THE WINDS WILL
CONTINUE MOSTLY FROM THE EAST UNTIL WEDNESDAY...BUT WILL SHIFT
FROM THE NORTHEAST AND INCREASING AS THE FRONTAL BOUNDARY
APPROACHES.

&&

.AVIATION...PREVAILING VFR CONDS AT ALL TERMINALS FOR THE NEXT 24
HRS. ISOLD-SCT SHRA EN ROUTE BTW ISLANDS...SCT020...SCT050 OCNL
BKN050...W/VCSH AT TJSJ...TJNR...TIST...TISX... TNCM...TKPK TIL
16/14Z. BRIEF MVFR PSBL W/PASSING SHRA AND MTN TOP OBSCR OVR ERN PR.
FM 16/17Z-16/22Z...SCT SHRA/ISOLD TSRA OVR CTRL AND WEST PR W/BRIEF
MVFR CONDS IN SHRA/ISOLD TSRA AT AND AROUND TJMZ... TJBQ. MOSTLY VFR
AFT 17/23Z. SFC WND FM E 10 KT OR LESS... EXCEPT W/PASSING SHRA...
BCMG FM ESE 10-15 KTS AFT 16/14Z...W/HIGHER GUST UP TO 22 KTS TIL
16/22Z. WINDS ALFT FM ESE 15-25 KT BLO FL280.

&&

.MARINE...SEAS UP TO 6 FEET AND WINDS UP TO 20 KNOTS WILL CONTINUE
ACROSS THE REGIONAL WATERS TODAY. SMALL CRAFT SHOULD EXERCISE
ACROSS MOST OF THE LOCAL WATERS.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 86 76 88 76 / 50 30 30 30
STT 87 77 87 77 / 40 50 50 30

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
329 PM AST MON NOV 16 2015

.SYNOPSIS...AT UPPER LEVELS...A WEAK RIDGE THROWN UP BY AN
APPROACHING TROUGH WILL PASS THROUGH THE AREA EARLY TUESDAY FROM
THE WEST. THE STRONG TROUGH WILL MOVE THROUGH ON THURSDAY
MORNING. ANOTHER RIDGE WILL BUILD OVER THE AREA UNTIL SATURDAY.

AT MID LEVELS...A RIDGE OF HIGH PRESSURE WILL CONTINUE NORTH OF
THE AREA UNTIL A STRONG TROUGH DIGS INTO THE WESTERN TROPICAL
ATLANTIC BRINGING NORTHERLY FLOW. THIS WILL BRING CONSIDERABLY
DRIER AIR LATER THURSDAY AND DURING THE DAY FRIDAY THAT WILL LAST
INTO TUESDAY ACCORDING TO THE LATEST RUN OF THE GFS.

AT LOWER LEVELS...HIGHER PRESSURE CONTINUES NORTH OF THE AREA INTO
EARLY NEXT WEEK. FLOW BECOMES MORE NORTHEASTERLY LATE THIS WEEK.
LOWER LEVELS CONTINUE MOIST...BRINGING RELATIVELY FREQUENT
BUT BRIEF SHOWERS. SHALLOW SHOWER ACTIVITY WILL PERSIST EVEN
AFTER LOW LEVELS DRY OUT LATE THIS WEEK.

&&

.DISCUSSION...SHOWERS FORMED IN THE LATE MORNING AND BEGAN MOVING
ACROSS PUERTO RICO. BY EVENING MOST OF THE ISLAND WILL HAVE
RECEIVED RAIN. SHOWERS IN THE U.S. VIRGIN ISLANDS HAVE MOSTLY BEEN
CONFINED TO SAINT CROIX WHERE 3 HUNDREDTHS FELL DURING THE MID
AFTERNOON. THE MIMIC PRODUCT REVEALS THAT THE BEAN-SHAPED AREA OF
MOISTURE MOVING ONSHORE IN PUERTO RICO AND OVER THE U.S. VIRGIN
ISLANDS STRETCHES BACK TO THE LEEWARD ISLANDS. THIS WILL PROVIDE
AMPLE MOISTURE FOR SHOWERS TO CONTINUE INTO THE EVENING OVER THE
AREA. OVERALL MOISTURE WILL ALSO INCREASE FOR THE NEXT 72 HOURS
WITH A WEAK REMISSION ON TUESDAY SUCH THAT MOST OF THE WEEK WILL
EXPERIENCE EAST SOUTHEAST FLOW AND GOOD SHOWER ACTIVITY. FOR NOW
THIS ACTIVITY LOOKS TO BE CARRIED BY REASONABLY STRONG TRADE WINDS
AND SO ANY URBAN AND SMALL STREAM FLOODING THAT OCCURS WILL BE
HIGHLY LOCALIZED TO AREAS WHERE SHOWERS TEND TO REFORM ALONG LINES
OF CONVERGENCE THAT FORM. MODELS STILL SHOW NORTHERLY FLOW
BEGINNING THURSDAY WITH MOISTURE BEING DRIVEN OUT BY FRIDAY. THIS
WILL REDUCE THE AMOUNT OF SHOWERS AND THE ACCUMULATIONS SEEN
DURING THE SHOWER ACTIVITY...BUT THE WET 850 MB LEVEL WILL LIKELY
FUEL SHOWERS ON THE NORTH AND EAST COASTS OF PUERTO RICO AND OVER
THE U.S. VIRGIN ISLANDS FOR LIMITED AMOUNTS.

THE GFS IS STILL BEHAVING ERRATICALLY. IN THE 16/06Z RUN IT HAD
DEPICTED THE WEEKEND AS RELATIVE MOIST...IT IS NOW SOMEWHAT DRY
AGAIN. NEVERTHELESS THE OVERALL IDEA OF A MINIMAL PENETRATION OF
DRIER AIR ALOFT LATE IN THE WEEK WITH WETTER WEATHER PRECEDING
STILL HOLDS.

&&

.AVIATION...MAINLY VFR CONDS EXPECTED ACROSS ALL TERMINALS FOR
THE NEXT 24 HRS. -SHRA AND VCSH STILL EXPECTED FOR TJSJ/TIST/TISX/
TNCM/TKPK...WITH BRIEF MVFR EXPECTED AT TJMZ/TJBQ THRU 16/22Z.
CLEARING AFT 16/23Z WITH JUST VCSH ACROSS TJSJ/TISX/TIST OVERNIGHT.
SFC WINDS FROM THE E-ESE AT 10 TO 15 KTS WITH HIGHER GUSTS...TURNING
CALM TO LIGHT AND VARIABLE OVERNIGHT.

&&

.MARINE...SEAS ARE PLATEAUING AT THIS TIME AND WILL BEGIN TO
DIMINISH. SEAS WILL INCREASE AGAIN DUE TO NORTHERLY FLOW ON
FRIDAY. SMALL CRAFT ADVISORIES MAY BE NEEDED FRIDAY AND SATURDAY.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 76 88 76 87 / 40 40 40 40
STT 77 87 77 87 / 70 70 40 40

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
546 AM AST TUE NOV 17 2015

.SYNOPSIS...A MID TO UPPER LEVEL TROUGH WILL CONTINUE TO AMPLIFY
ACROSS THE WESTERN AND CENTRAL CARIBBEAN THROUGH WEDNESDAY AND
THEN ACROSS THE NORTHEAST CARIBBEAN THURSDAY AND FRIDAY AS A
FRONTAL BOUNDARY MOVES OVER THE REGION. A SURFACE HIGH PRESSURE
EMERGING ACROSS THE EASTERN UNITED STATES SEABOARD WILL PROMOTE A
LOW LEVEL NORTHEAST WIND FLOW ACROSS THE REGION WEDNESDAY THROUGH
AT LEAST SATURDAY.

&&

.DISCUSSION...AN AREA OF MOISTURE EMBEDDED IN THE TRADES WILL
CONTINUE TO PROMOTE THE DEVELOPMENT OF SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS ACROSS EASTERN SECTIONS OF PUERTO RICO
DURING THE EARLY MORNING HOURS. BY THE AFTERNOON HOURS...THIS
MOISTURE IN COMBINATION WITH LOCAL EFFECTS WILL PRODUCE SHOWERS
AND THUNDERSTORMS OVER WESTERN AND INTERIOR SECTIONS OF PUERTO
RICO. A MID TO UPPER LEVEL TROUGH IS EXPECTED TO AMPLIFY ACROSS
THE NORTHEAST CARIBBEAN THURSDAY AND FRIDAY.

A SURFACE HIGH PRESSURE EMERGING OVER THE WESTERN ATLANTIC WILL
PUSH A FRONTAL BOUNDARY ACROSS THE REGION ON THURSDAY. AS THE
FRONTAL BOUNDARY APPROACHES THE WINDS WILL INCREASE AND BECOME
FROM THE NORTHEAST LATE WEDNESDAY AND INTO AT LEAST SATURDAY.
THIS WIND FLOW WILL TRANSPORT PATCHES OF LOW LEVEL MOISTURE ACROSS
THE LOCAL ISLANDS. A DECREASE IN MOISTURE IS EXPECTED BY FRIDAY
AS THE FRONTAL BOUNDARY MOVES ACROSS THE CARIBBEAN WATERS SOUTH OF
PUERTO RICO...BUT SOME PASSING SHOWERS EMBEDDED IN THE
NORTHEASTERLY WIND FLOW OVER THE NORTHERN SECTIONS OF PUERTO RICO
ARE NOT RULE OUT.

&&

.AVIATION...PREVAILING VFR CONDS AT ALL TERMINALS FOR THE NEXT 24
HRS. SCT-BKN CLD LYRS...FL020...FL050...FL100. HOWEVER PASSING TRADE
WIND SHRA/AND OR ISOLD TSRA MAY AFFECT TJSJ/TJNR/TIST/TISX/TNCM/
TKPK TIL 17/12Z. THIS WILL LEAD TO BRIEF MVFR DUE TO LOW CLDS AND
VIS 4-5SM IN SHRA. MTN TOP OBSCR OVR ERN PR DUE TO LOW SCUD CLDS AND
-RA/SHRA. FEW CB N AND S OF PR...ISOLD MAX TOP 340 TIL 17/12Z. LOW
LEVEL SFC WNDS WILL BE LIGHT AND VARIABLE TIL 17/14Z... BCMG FM E-SE
10 TO 15 KTS WITH OCNL HIGHR GUST AFTER 17/14Z TIL 17/22Z.

&&

.MARINE...SEAS ARE EXPECTED TO REMAIN UP TO 5 OR 6 FEET ACROSS THE
LOCAL WATERS THROUGH MUCH OF THIS WEEK. NORTHERLY SWELL EXPECTED
TO MOVE IN LATE THIS WEEK AND CAUSE SEAS TO GRADUALLY BECOME MORE
HAZARDOUS BY FRIDAY AND THROUGH THE UPCOMING WEEKEND.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 87 76 88 76 / 40 40 40 30
STT 86 77 87 76 / 50 40 40 30

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
309 PM AST TUE NOV 17 2015

.SYNOPSIS...STRONG MID-UPPER LEVEL TROUGH WILL CROSS THE REGION BY
THURSDAY MORNING. THIS TROUGH IS SUPPORTING A FRONTAL BOUNDARY THAT
WILL MOVE ACROSS THE REGION FROM WEDNESDAY AFTERNOON INTO THURSDAY.
SHALLOW CONVECTION IS LIKELY FRIDAY THROUGH THE WEEKEND AS A COOL
ADVECTIVE PATTERN ESTABLISH BEHIND OF THE FRONT.

&&

.DISCUSSION...MID-UPPER LEVEL CLOUDINESS AND FAIRLY DRY AIR MASS...
LIMITING THE SHOWER ACTIVITY ACROSS THE LOCAL ISLANDS TODAY. GPS
MET DATA SHOWED PRECIPITABLE WATER DROPPED TO 1.7 INCHES THIS
AFTERNOON. HOWEVER...LATE AFTERNOON CONVECTION IS POSSIBLE AS SEA
BREEZES WILL INDUCE THE LATE SHOWER ACTIVITY OVER NORTHWESTERN
PR. ANOTHER BAND OF MOISTURE WILL MOVE OVER THE USVI AND PR TONIGHT
INTO WEDNESDAY...BRINGING SCATTERED SHOWERS TO THE WINDWARD SIDE
OF THE ISLANDS. LOW LEVEL CONVERGENCE ASSOCIATED WITH A PREFRONTAL
TROUGH/SHEAR LINE...DECENT MOISTURE AND MID LEVEL ENERGY OF THE
AFORMENTIONED UPPER LEVEL TROUGH WILL RESULT IN MODERATE TO DEEP
CONVECTION ACROSS THE WESTERN HALF OF PUERTO RICO ON WEDNESDAY
AFTERNOON. ON THURSDAY...THE FRONTAL BOUNDARY IS FORECAST TO APPROACH
AND PROBABLY CROSS THE LOCAL ISLANDS. MOST ACTIVE IS TO AFFECT TO
NORTHERN VI AND PUERTO RICO...WITH POTENTIAL FOR MODERATE CONVECTION
DURING THE DAY ON THURSDAY. TRADE WIND SHOWERS WILL PESTER THE
NORTHERN VI...NORTH AND NORTHEAST PR FRIDAY THROUGH THE WEEKEND.

&&

.AVIATION...MAINLY VFR CONDS EXPECTED ACROSS ALL TERMINALS FOR
THE NEXT 24 HRS WITH SOME VCSH. BRIEF PDS OF MVFR EXPECTED AT
TJMZ/TJBQ THRU 17/22Z IN SHRA AND TSRA...CLEARING AFT 17/23Z. SFC
WINDS FROM THE E-ESE AT 10 TO 15 KTS WITH HIGHER GUSTS...TURNING
CALM TO LIGHT AND VARIABLE OVRNGHT.

&&

.MARINE...A MODERATE TRADE WIND FLOW WILL PREVAIL ACROSS THE
REGIONAL WATERS THROUGH WEDNESDAY. PULSES A NORTHERLY SWELL WILL
REACH THE LOCAL WATERS FROM FRIDAY THROUGH THE WEEKEND.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 76 88 76 85 / 40 40 30 30
STT 77 87 76 87 / 20 40 30 30

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
550 AM AST WED NOV 18 2015

.SYNOPSIS...AT UPPER LEVELS...A WEAK TROUGH ACROSS EASTERN CUBA
THIS MORNING EXTENDING FROM A STRONG LOW IN THE WEST CENTRAL
ATLANTIC WILL MOVE ACROSS PUERTO RICO AND THE U.S. VIRGIN ISLANDS
THURSDAY. FLOW WILL BECOME MORE WEST NORTHWEST WHEN HIGH PRESSURE
SPREADS OVER THE EASTERN CARIBBEAN AS THE LOW ROTATES OUT OF THE
AREA FRIDAY AND SATURDAY. THE JET AHEAD OF THE NEXT TROUGH TO PASS
WILL PASS OVERHEAD WEDNESDAY NIGHT OF THE FOLLOWING WEEK.

AT MID LEVELS...A RIDGE EXTENDS FROM SOUTH CAROLINA TO THE WESTERN
TROPICAL ATLANTIC. A TROUGH WILL DIG INTO THE WESTERN TROPICAL
ATLANTIC TODAY AND THURSDAY. THEN HIGH PRESSURE WILL BUILD WEAKLY OVER
THE AREA OVER THE WEEKEND. TROUGHINESS RETURNS MID WEEK NEXT WEEK.
A BAND OF MODEST MOISTURE MOVES OVER THE FORECAST AREA TONIGHT
BUT CLEARS RAPIDLY THURSDAY AND FRIDAY AND MID LEVELS BECOME VERY
DRY. MOISTURE RETURNS MID WEEK NEXT WEEK.

AT LOWER LEVELS...HIGH PRESSURE OVER THE WESTERN ATLANTIC WILL
DIMINISH AS LOW PRESSURE GROWS OVER THE CENTRAL ATLANTIC TODAY
THROUGH FRIDAY. THAT LOW WILL PULL NORTH...BUT AS IT DOES SO LOW
PRESSURE WILL DEEPEN OVER THE NORTHERN BAHAMA ISLANDS SATURDAY
NIGHT AND SUNDAY. THE LOW WILL MOVE NORTHEAST AND PULL AN
ACCOMPANYING TROUGH AND SHOWERS OVER THE LOCAL AREA MONDAY NIGHT
AND TUESDAY. THE SHOWERS WILL CONTINUE THROUGH MOST OF THE WEEK
NEXT WEEK AND WINDS WILL BE RELATIVELY WEAK.

&&

.DISCUSSION...EASTERLY FLOW HAS BROUGHT SHOWERS TO PUERTO RICO
AND THE U.S. VIRGIN ISLANDS OVERNIGHT. SHOWERS WERE BRIEF.
ACCUMULATIONS WERE LIGHT IN THE U.S. VIRGIN ISLANDS...BUT A FEW OF
THE SHOWERS IN EASTERN PUERTO RICO AND ALONG THE NORTH COAST WERE
MODERATE TO HEAVY WITH SOME LEAVING MORE THAN ONE TENTH INCH OF
RAIN. SHOWERS WILL INCREASE TODAY AND TONIGHT AS WINDS BECOME MORE
NORTHERLY WITH THE APPROACH OF A COLD FRONT FROM THE NORTH
NORTHEAST. FORECAST INSTABILITY REACHES A MAXIMUM FOR THE NEXT 10
DAYS TODAY...WITH A LIFTED IN INDEX OF AROUND MINUS 6. THIS
SHOULD BE SUFFICIENT FOR AT LEAST ISOLATED THUNDERSTORMS. MID
LEVEL MOISTURE BEGINS TO DIMINISH EARLY THURSDAY MORNING AND IS
COMPLETELY GONE BY THURSDAY NIGHT. THEN RELATIVE HUMIDITIES AT 600
MB ARE FORECAST BY THE GFS TO STAY IN THE SINGLE DIGITS UNTIL
SUNDAY EVENING. THIS SHOULD RESTRICT TOPS TO LESS THAN 12 KFT AND
POTENTIAL THUNDERSTORM ACTIVITY TO ALMOST NIL.

ALTHOUGH MID LEVELS DRY OUT...LOWER LEVELS ARE GENERALLY MOIST WITH
A FEW DRY BANDS MOVING THROUGH AND THIS WILL KEEP LIGHT SHOWERS
PREVALENT ON THE WINDWARD SIDE OF THE ISLANDS. THE MOST NOTABLE
DRY BAND AT 850 MB COMES THROUGH FRIDAY NIGHT AND SOME CLEARING IS
EXPECTED THEN. THIS ALSO COINCIDES WITH THE HIGHEST LIFTED INDEX
OF THE NEXT 10 DAYS COMING IN JUST BELOW 3. THEN FLOW TURNS TO
THE EAST AT LOWER LEVELS AND MOISTURE PUNCHING IN IS EXPECTED TO
FORM SHOWERS ALONG THE NORTHERN U.S. VIRGIN ISLANDS AND OVER OR
JUST NORTH OF THE NORTH COAST OF PUERTO RICO SATURDAY AFTERNOON.
MOISTURE THEN CONTINUES ALL NEXT WEEK WITH SHOWER ACTIVITY
ENHANCED BY AN UPPER LEVEL TROUGH MID WEEK NEXT WEEK. CURRENTLY
THE GFS IS EXPECTING A SHOWERY THANKSGIVING DAY.

&&

.AVIATION...MAINLY VFR CONDS EXPECTED AT ALL TERMINALS DURING THE
FCST PERIOD. HOWEVER PASSING TRADE WIND SHRA MAY AFFECT TJSJ/TJNR/
TIST/TISX/TNCM/TKPK DURING THE MORNING HOURS...THEN AFT 18/17Z
MOUNT OBSCURATIONS ARE EXPECTED ALONG THE CORDILLERA CENTRAL
LEADING TO BRIEF MVFR DUE TO LOW CLDS AND VIS 4-5SM IN SHRA/TSRA
OVER TJMZ/TJBQ. MTN TOP OBSCURATIONS OVR ERN PR DUE TO AFTERNOON
SHRA/ISOLATED SHRA/TSRA ARE ALSO POSSIBLE. SFC WNDS WILL BE FM THE
E-NE AT 10 TO 15 KTS WITH OCNL HIGHER GUST AND SEA BREEZE
VARIATIONS AFTER 17/13Z.


&&

.MARINE...SEAS WILL DIMINISH TODAY THROUGH THURSDAY MORNING...BUT
WILL INCREASE CONSIDERABLY THEREAFTER UNTIL FRIDAY MORNING IN
NORTH NORTHEAST SWELL. SMALL CRAFT ADVISORIES ARE EXPECTED
BEGINNING EARLY FRIDAY FOR THE ATLANTIC WATERS AND PASSAGES.
ANOTHER PULSE WILL MOVE IN BEGINNING SATURDAY AND LAST INTO
SUNDAY.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 76 86 76 / 50 60 70 60
STT 87 76 89 75 / 50 60 60 40

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
307 PM AST WED NOV 18 2015

.SYNOPSIS...STRONG MID-UPPER LEVEL TROUGH WILL CROSS THE REGION BY
THURSDAY MORNING. THIS TROUGH IS SUPPORTING A FRONTAL BOUNDARY THAT
IS FORECAST TO MOVE ACROSS THE REGION FROM TONIGHT INTO THURSDAY.
OCCASIONAL SHOWERS ARE LIKELY FRIDAY THROUGH THE WEEKEND AS A COOL
ADVECTIVE PATTERN ESTABLISH BEHIND OF THE FRONT. STABLE AND DRY
AIR MASS WILL DOMINATE THE MID-UPPER LEVEL FROM FRIDAY THROUGH THE
WEEKEND LIMITING THE POTENTIAL OF THUNDERSTORM ACROSS THE LOCAL
REGION.

&&

.DISCUSSION...MID-UPPER LEVEL CLOUDINESS HAVE LIMITED THE SHOWER
ACTIVITY ACROSS THE ISLANDS TODAY. WEAK TEMPERATURE GRADIENTS
BETWEEN WATER AND LAND...INDUCED LIGHT SEA BREEZES ACROSS PR.
HOWEVER...SOME CONVECTION HAVE BEEN DEVELOPING ACROSS THE INTERIOR
AND WESTERN HALF OF PUERTO RICO THIS AFTERNOON. LOW LEVEL CONVERGENCE
ASSOCIATED WITH THE BOUNDARY...HIGH MOISTURE AND MID-UPPER LEVEL
ENERGY WILL KEEP THE POTENTIAL FOR SHOWERS AND THUNDERSTORMS
FAIRLY HIGH THROUGH THURSDAY. GFS ENSEMBLE SUGGESTS THAT THE
FRONTAL BOUNDARY IS FORECAST TO MOVE OVER THE LOCAL REGION BY
THURSDAY MORNING. MOST ACTIVE PERIOD IS EXPECTED OVERNIGHT AND
THURSDAY MORNING OVER NORTHERN VI AND PUERTO RICO...WITH POTENTIAL
FOR MODERATE CONVECTION OVER THE SOUTHERN HALF OF PUERTO RICO ON
THURSDAY AFTERNOON. ALTHOUGH...DRIER AND MORE STABLE AIR MASS IS
FORECAST FROM FRIDAY THROUGH THE WEEKEND...TRADE WIND SHOWERS WILL
PESTER THE USVI NORTH AND NORTHEAST PR FRIDAY THROUGH THE WEEKEND.

&&

.AVIATION...BRIEF MVFR DUE TO SHRA/TSRA OVER TJMZ/TJBQ POSSIBLE
TILL 22Z. THEN AS FRONTAL BOUNDARY MOVES FROM THE ATLC WATERS INTO
THE EASTERN CARIBBEAN OVERNIGHT AND LOW LEVEL STEERING WINDS CHANGE
FROM THE ENE...EXPECT SHRA MAINLY OVER THE ATLANTIC WATERS AND
PASSAGES WITH A FEW OF THEM AFFECTING FROM TIME TO TIME THE NORTHERN
TERMINALS OF PR...AND THE USVI TERMINALS. MAINLY VFR ELSEWHERE. BY
19/00Z LOW LEVEL WINDS WILL TURN ENE AT 10-15 KTS...INCREASING 15-
30 KTS BETWEEN FL100-200 BY 19/12Z.

&&

.MARINE...PULSES OF NORTHERLY SWELLS OF 6-8 FEET WILL REACH THE
LOCAL ATLANTIC WATERS AND LOCAL CARIBBEAN PASSAGES FROM FRIDAY
THROUGH EARLY NEXT WEEK. THESE LONG PERIOD SWELLS WILL LIKELY
CREATE HIGH SURF ALONG THE NORTH FACING COASTS OF PUERTO RICO...
CULEBRA AND VIEQUES.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 76 86 76 85 / 60 40 60 50
STT 76 89 75 88 / 60 40 40 40

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
505 AM AST THU NOV 19 2015

.SYNOPSIS...THE PERIPHERY OF A STRONG UPPER LEVEL TROUGH WILL PASS
THROUGH THE FORECAST AREA TODAY. HIGH PRESSURE WILL BUILD OVER THE
AREA FRIDAY FROM THE WESTERN CARIBBEAN AND PERSIST THROUGH
TUESDAY. A WEAK TROUGH WILL PASS THROUGH EARLY WEDNESDAY. FLOW
WILL SHIFT TO THE SOUTHWEST DURING THE LATTER PART OF NEXT WEEK AS
ANOTHER TROUGH DIG SOUTH INTO CUBA.

AT MID LEVELS...HIGH PRESSURE OVER THE BAHAMA ISLANDS WILL SHIFT
SOUTHWARD OVER THE WEEKEND WHILE A TROUGH FROM THE WEST CENTRAL
ATLANTIC STRETCHING INTO THE WESTERN TROPICAL ATLANTIC PULLS INTO
THE CENTRAL ATLANTIC. HIGH PRESSURE WILL REMAIN IN CONTROL OF THE
CARIBBEAN UNTIL A WEAK TROUGH PASSES TO THE NORTH ON WEDNESDAY OF
NEXT WEEK. MOISTURE AT MID LEVELS WILL BEGIN DIMINISHING TODAY AND
BY LATE TONIGHT WILL HAVE BECOME INSIGNIFICANT. SOME MOISTURE
RETURNS ON SATURDAY AT THE LOWEST MID LEVELS...OTHERWISE LIMITED
MOISTURE WILL RETURN EARLY NEXT WEEK.

AT LOWER LEVELS...HIGH PRESSURE IN THE WESTERN ATLANTIC WEAKENS
BUT REMAINS THERE UNTIL SUNDAY. LOW PRESSURE IN THE CENTRAL
ATLANTIC STRENGTHENS UNTIL FRIDAY AND THEN PULLS RAPIDLY UP INTO
THE NORTH ATLANTIC...LEAVING MODERATE TRADE WINDS OVER THE AREA.
A TROUGH FORMS OVER THE BAHAMAS SATURDAY AND SUNDAY AND THEN
SHIFTS TO OVER THE FORECAST AREA BY TUESDAY NIGHT. THIS WILL
WEAKEN LOCAL WINDS BY TUESDAY AND BRING AN INCREASE IN SHOWERS.

&&

.DISCUSSION...SHOWERS IN THE BAND OF CONVECTION ASSOCIATED WITH
THE APPROACHING FRONT FORMED NORTH OF THE AREA AND SLOWLY GATHERED
ENOUGH STRENGTH TO ARRIVE ONSHORE IN PUERTO RICO FROM DORADO TO
CAMUY. SHOWERS WERE ALSO APPROACHING THE NORTHERN U.S. VIRGIN
ISLANDS FROM THE NORTHEAST. THIS TREND IS EXPECTED TO CONTINUE
RESULTING IN SCATTERED SHOWERS ON THE NORTH COAST AND NORTHERN
TIER OF THE U.S VIRGIN ISLAND THIS MORNING WITH LIGHT
ACCUMULATIONS. THIS AFTERNOON THE SHOWERS WILL ALSO BE ENHANCED
BY LOCAL HEATING OVER THE INTERIOR OF PUERTO RICO AND SPREAD TO
THE INTERIOR AND INTO THE SOUTHWEST AND OFFSHORE. AT THIS TIME
URBAN AND SMALL STREAM FLOODING IS NOT ANTICIPATED THROUGH THE
WEEKEND. SHOWERS WILL CONTINUE TO COME INLAND ON THE
NORTHEASTERLY FLOW TONIGHT AND FRIDAY...BUT THE MOISTURE WILL
DECREASE RAPIDLY AS THE MID LAYERS DRY OUT AND BOTH THE STRENGTH
AND COVERAGE OF THE SHOWERS WILL DIMINISH CONSIDERABLY. ON
SATURDAY ANOTHER BAND OF MOISTURE WILL DESCEND OUT OF THE NORTH
OVER THE AREA AND BRING SCATTERED BUT SHALLOW SHOWERS WITH VERY
LIGHT ACCUMULATIONS. THERE IS LITTLE CHANCE OF THUNDERSTORMS
FRIDAY AND SATURDAY DUE TO THE WITHERING DRYNESS OF THE MID LAYERS
AFTER FRIDAY. PATCHES OF LOW LEVEL MOISTURE WILL CONTINUE TO CROSS
THROUGH THE AREA ON EASTERLY FLOW MOST OF NEXT WEEK. A TROUGH
MIGRATING FROM THE WEST EARLY NEXT WEEK WILL ALSO REPLENISH SOME
OF THE MOISTURE AND BRING BETTER SHOWER ACTIVITY...ESPECIALLY OVER
THE INTERIOR AS WINDS WILL BECOME LIGHTER AND LOCAL CONVERGENCE
WILL COME INTO PLAY.

&&

.AVIATION...AS A FRONTAL BOUNDARY MOVES CLOSER TO LOCAL ISLANDS THIS
MORNING...EXPECT ENE WINDS WITH PERIODS OF SHRA/TSRA POSSIBLE AT THE
NORTHERN TERMINALS OF PR AND USVI AND VCSH AT THE LEEWARD TERMINALS
THROUGH THE FCST PERIOD. AFT 19/16Z SHRA/TSRA WILL INCREASE MAINLY
OVER THE CENTRAL MOUNTAIN RANGE AND OVER SOUTHWESTERN PR...TO
PRODUCE MVFR CONDITIONS AT TJMZ/TJPS. ENE WINDS AT 10 TO 15
KTS WITH SEA BREEZE VARIATIONS AFT 19/13Z.

&&

.MARINE...SEAS HAVE BEEN MOSTLY 3 TO 5 FEET ACROSS THE FORECAST
AREA. THE SWELL ANTICIPATED FOR TONIGHT IS STILL EXPECTED TO
ARRIVE...BUT SEAS AT BUOY 41043 SPIKED TO 7.2 FEET JUST AFTER THE
COASTALS WERE SENT. SHOULD THIS PROVE TO BE A VALID READING WOULD
EXPECT SEAS TO RISE TO NEAR 7 FEET BY LATE THIS AFTERNOON IN
NORTHERLY SWELL. WILL CONSIDER UPDATING THE FORECAST LATER THIS
MORNING.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 87 76 85 76 / 40 50 30 30
STT 86 78 87 77 / 40 30 20 40