Caribbean - Central America Weather

[Macrocane]

Interesting January in Puerto Rico as high temperatures records and now rainfall records have been broken.

[cycloneye]

As of 7 AM AST 8.63 inches of rain on first days of January

The January 2010 new record keeps building.

http://www.srh.noaa.gov/sju/?n=record100114

A record rainfall of 2.56 inches fell at the Luis Muñoz Marin International Airport in San Juan Puerto Rico on January 13, 2010. This broke the old record of 1.85 inches set back in 1959. Additionally, a record 3.51 inches of rain fell at the Luis Muñoz Marin International Airport on January 14, 2010. This surpasses the old record rainfall total of 1.13 inches set back in 1996. While the single day record for rainfall in the month of January stands at 4.98 inches, which fell on January 26, 1969, the two day rainfall of 6.07 inches represents the wettest 2 day period ever record in San Juan during the month of January. With an additional 0.64 inches of rainfall as of 7 am AST on January 15, 2010, the monthly rainfall total stands at 8.63 inches. The record rainfall for January 15th is 2.69 inches, which accumulated back in 2006.

After the 3rd driest December on record, January 2010 has now surpassed January 1977, and stands as the single wettest January ever recorded at the Luis Muñoz Marin International Airport in San Juan. In addition, the high Temperature of only 76 degrees recorded January 14, 2010, tied the coolest high temperature ever recorded for the date and represents the coolest high temperature in San Juan since January 21, 2008, when the high temperature also reached only 76 degrees. The coolest high temperature ever recorded at the Luis Muñoz International Airport was 73 degrees, which occurred on January 18, 2000.

[cycloneye]

Afternoon Discussion by San Juan NWS

More of the same here and that is rain,rain,rain and fresh breezes.Yes Macrocane,is an irony as weather has turned 360 degrees.

http://forecast.weather.gov/product.php ... glossary=1

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
252 PM AST FRI JAN 15 2010

.SYNOPSIS...STATIONARY FRONT EXTENDING ACROSS PUERTO RICO WILL
MAINTAIN CLOUDY AND SHOWERY CONDITIONS THROUGH TONIGHT. SLOWLY
IMPROVING CONDITIONS ARE EXPECTED AFTER SUN AS FRONT DISSIPATES
AND MID-UPPER LVL RIDGING BUILDS OVERHEAD.

&&

.DISCUSSION...A CONSTANT LIGHT TO MODERATE RAIN CONTINUE TO AFFECT
THE EASTERN AND NORTHERN PORTIONS OF PUERTO RICO. THE DOPPLER
RADAR IS ALSO SHOWING AN AREA OF MODERATE SHOWERS OVER THE
SOUTHWEST PORTIONS OF PUERTO RICO. THE BULK OF THE HEAVIEST
SHOWERS MOVED SOUTHWARD OVER THE CARIBBEAN WATERS. STRATIFIED RAIN
WILL CONTINUE TO AFFECT PUERTO RICO THROUGH AT LEAST SATURDAY. ON
SATURDAY MORNING THE BULK OF MOISTURE WILL MOVE OVER THE ISLAND
GENERATING MORE RAIN ACROSS THE NORTHERN AND EASTERN PORTIONS OF
PUERTO RICO THROUGH SUNDAY.

MORE SHOWERS OVER THESE AREAS COULD INCREASE EVEN MORE THE
POTENTIAL FOR FLASH FLOOD AND MUD SLIDES ACROSS THE ISLAND BUT
MAINLY THE INTERIOR AND NORTHERN PORTION OF THE ISLAND.


&&

.AVIATION...PREVAILING MVFR CIGS AND VSBY WILL CONTINUE ACROSS
TJSJ...TJBQ...TJPS AND TIST THROUGH AT LEAST 16/02Z...WITH TEMPORARY
IFR CONDS POSSIBLE. PREVAILING VFR CONDITIONS EXPECTED ACROSS
REMAINDER OF TAF SITES...WITH BRIEF MVFR CONDITIONS POSSIBLE ACROSS
TNCM...TISX...AND TJMZ THROUGH 16/02. VA EMISSIONS CONTINUING FROM
MONTSERRAT BUT WILL REMAINS OUT OF THE LOCAL TAF SITES AS FLOW IS
EXPECTED TO REMAIN FROM THE ENE FOR THE NEXT 24 HOURS. LATEST TJSJ
SOUNDING INDICATED AN EAST NORTHEAST WIND FLOW UP TO 25 KNOTS FROM
THE SURFACE TO AROUND 10K FEET...BECOMING LIGHT AND VARIABLE FROM
10K-25K FEET AND THEN WESTERLY AND STRONGER ALOFT.

&&

.MARINE...WINDS OF AROUND 20 KNOTS WILL GENERATE CHOPPY SEAS
ACROSS THE LOCAL WATERS. ALTHOUGH THE BUOY 41043 (OUTSIDE THE
LOCAL WATERS)IS SHOWING SEA HEIGHTS OF LESS THAN 7 FEET...THE
STRONG WINDS HAVE CONCENTRATED ACROSS THE LOCAL ATLANTIC WATERS.
THEREFORE A SMALL CRAFT ADVISORY IS IN EFFECT FOR ALL ATLANTIC
WATERS AND PASSAGES.

[cycloneye]

Flash Flood Watch extended until Saturday Morning

FLOOD WATCH
NATIONAL WEATHER SERVICE SAN JUAN PR
812 PM AST FRI JAN 15 2010

PRZ001-002-004>006-161200-
/O.EXT.TJSJ.FF.A.0001.000000T0000Z-100116T1200Z/
/00000.0.OT.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SAN JUAN AND VICINITY-NORTHEAST-EASTERN INTERIOR-NORTH CENTRAL-
CENTRAL INTERIOR-
INCLUDING THE MUNICIPALITIES AND/OR ISLANDS OF...SAN JUAN...
CAROLINA...FAJARDO...HUMACAO...CAGUAS...ARECIBO...VEGA BAJA...
DORADO...COAMO...COROZAL...AIBONITO...VILLALBA...JAYUYA
812 PM AST FRI JAN 15 2010

...FLASH FLOOD WATCH NOW IN EFFECT THROUGH SATURDAY MORNING...

THE FLASH FLOOD WATCH IS NOW IN EFFECT FOR

* A PORTION OF PUERTO RICO...INCLUDING THE FOLLOWING AREAS...
CENTRAL INTERIOR...EASTERN INTERIOR...NORTH CENTRAL...NORTHEAST
AND SAN JUAN AND VICINITY.

* THROUGH SATURDAY MORNING

* THE FRONTAL BOUNDARY DRAPED ACROSS NORTHERN PUERTO RICO DURING
THE LAST FEW DAYS...IS FORECAST TO REMAIN NEARLY STATIONARY
ACROSS THE ISLAND FOR THE NEXT 24 HOURS. WHILE RAINFALL IS NOT
EXPECTED TO BE CONTINUOUSLY HEAVY...ANY ADDITIONAL RAINFALL WILL
AGGRAVATE THE PRESENT SITUATION ACROSS MUCH OF THE NORTHERN AND
EASTERN SECTIONS OF PUERTO RICO. DUE TO ALREADY SATURATED
SOILS... AND RIVERS AND STREAMS STILL AT HIGH LEVELS...ADDITIONAL
RAINFALL COULD LEAD TO FLOODING OF SMALL STREAMS...CREEKS AND
RIVERS ACROSS THESE SECTORS OF THE ISLAND. IN ADDITION...THERE
HAVE BEEN SEVERAL REPORTS OF MUDSLIDES AND ROCKFALL IN AREAS OF
STEEP TERRAIN. AS A RESULT...A FLASH FLOOD WATCH REMAINS IN
EFFECT FOR MUCH OF THE NORTHERN AND EASTERN PUERTO RICO THROUGH
8 AM AST SATURDAY MORNING.

* DUE TO SWOLLEN RIVERS AND ALREADY SATURATED SOILS...ANY
ADDITIONAL HEAVY RAINFALL COULD CAUSE RIVERS TO COME OUT OF
THEIR BANKS. MUDSLIDES AND ROCKFALL WILL CONTINUE TO BE A
SIGNIFICANT THREAT IN AREAS OF STEEP TERRAIN.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A FLASH FLOOD WATCH MEANS THAT CONDITIONS ARE FAVORABLE FOR HEAVY
RAIN ACROSS THE WATCH AREA...WHICH MAY LEAD TO FLOODING. IF YOU ARE
IN THE WATCH AREA...CHECK YOUR PREPAREDNESS REQUIREMENTS...
ESPECIALLY IF YOU HAVE INTERESTS ALONG AREA RIVERS. KEEP INFORMED...
AND BE READY FOR QUICK ACTION IF FLOODING IS OBSERVED OR IF A FLASH
FLOOD WARNING IS ISSUED.

PEOPLE IN THE WATCH AREA SHOULD CONTINUE TO BE AWARE OF THE
POSSIBILITY FOR HEAVY RAINFALL. AVOID LOW LYING AREAS...AND BE
CAREFUL WHEN APPROACHING HIGHWAY DIPS AND UNDERPASSES. IN ADDITION
THE HEAVY RAIN COULD EVENTUALLY CAUSE MUDSLIDES IN AREAS OF STEEP
TERRAIN.

STAY TUNED TO NOAA WEATHER RADIO...LOCAL TV...RADIO OR YOUR CABLE
TELEVISION PROVIDER FOR LATER STATEMENTS AND POSSIBLE WARNINGS.

THIS PRODUCT...ALONG WITH OTHER WEATHER...HYDROLOGICAL AND CLIMATE
INFORMATION...IS AVAILABLE ON THE WEB AT HTTP://WWW.SRH.NOAA.GOV/SJU
OR AT HTTP://WEATHER.GOV.

[cycloneye]

Good morning to all.Still some showers for today,but conditions will be improving slowly.


AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
422 AM AST SAT JAN 16 2010

.SYNOPSIS...STATIONARY FRONT ACROSS PR WILL SLOWLY DISSIPATE OVER
THE NEXT 24 HRS. BUILDING MID-UPPER LEVEL HIGH PRES WILL PROMOTE A
DRYING TREND ACROSS THE REGION BEGINNING SUN NIGHT THAT SHOULD
LAST THROUGH MUCH OF THE NEW WORK WEEK.

&&

.DISCUSSION...LATEST SATELLITE IMAGERY SHOWS BREAKS IN THE CLD CVR
ACROSS NORTH NORTHEAST SECTIONS OF PR WHILE THE WRN HALF IS
EXPERIENCING M/CLEAR SKIES. MODEL GUIDANCE SHOWS FRONT WEAKENING
RAPIDLY OVR THE NEXT 24 HRS AND 02Z AMDAR DATA SHOWED SUBSIDENCE
CAP HAS STRENGHTENED/LOWERED TO 700 MB. THIS WOULD ARGUE AGAINST
ANY HEAVY RAINFALL TODAY WITH MUCH LOWER RAINFALL RATES THAN
EXPERIENCED YESTERDAY. HOWEVER...STILL EXPECT SHOWERY CONDITIONS
ESPECIALLY IN THE MORNING BUT WITH A FEW GLIMPSES OF SUN
ESPECIALLY FOR THOSE ALONG THE NORTH/NORTHEAST COAST. STILL SOME
SHOWERS POSSIBLE SUN BUT IMPROVING CONDITIONS. THE ONLY CONCERN IS
FOR WINDS AT HIGHER ELEVATIONS TODAY THROUGH MONDAY WHERE MODELS
SHOW 25-KT WINDS AT 2KFT. FOR NOW WILL CONTINUE TO MONITOR.

FRONT WASHES OUT BY SUNDAY WITH STRONG MID-UPPER LEVEL RIDGE
TAKING FULL CONTROL OF THE REGION PROMOTING A DRYING TREND.

&&

.AVIATION...PREVAILING MVFR CONDS EXPECTED ACROSS ALL THE LOCAL TAF
SITES THROUGH 16/14Z...WITH BRIEF IFR CONDS POSSIBLE MAINLY ACROSS
TJSJ...TJBQ...TIST...TISX AND TNCM. IMPROVING CONDS... WITH
PREVAILING VFR CONDS AND VERY QUICK PASSING MVFR CONDS...EXPECTED
ACROSS ALL TAF SITES AFTER 16/14Z. LATEST EMISSIONS FROM MONTSERRAT
CONTINUE TO SPEW VA IN THE EASTERN CARIBBEAN...BUT THIS VA WILL
REMAIN SOUTH OF ALL TAF SITES IN A EASTERLY WIND FLOW OF 10-15G25KTS.


&&

.MARINE...NRLY SWELLS WILL CONTINUE TO SLOWLY SUBSIDE THROUGH SUN.
HOWEVER...TIGHTENING PRES GRADIENT WILL RESULT IN STRONG TRADE WINDS
AND ENE GENERATED WIND WAVES OF 6-8 FT ACROSS ATLC WATERS AND
ANEGADA PASSAGE THROUGH SUN NIGHT. SEAS EXPECTED TO FALL BELOW SCA
CRITERIA MONDAY. PLEASE REFER TO LATEST MWW MESSAGE FOR HEADLINES.


&&

.CLIMATE...A RECORD 9.01 INCHES OF RAIN HAS NOW ACCUMULATED AT THE
LUIS MUNOZ MARIN INTERNATIONAL AIRPORT IN SAN JUAN THIS JANUARY. THE
PREVIOUS RECORD JANUARY RAINFALL WAS 7.60...WHICH ACCUMULATED IN
JANUARY 1977. SEE http://WWW.WEATHER.GOV/SANJUAN FOR A NEWS STORY DETAILING
MORE INFORMATION ABOUT CLIMATE RECORDS BROKEN THE PAST FEW DAYS.

[Gustywind]

[Macrocane]

I have posted the observations from the last cold front that affected Centralamerica on this thread: http://www.storm2k.org/phpbb2/viewtopic.php?f=22&t=106879
It's one of the longest reports that I've done because the event lasted for several days and moved down to Costa Rica so I've included data from the usual 3 cities (Guatemala, Tegucigalpa and San Salvador), as well from Belize, Managua and San Jose.

[Macrocane]

I have also uploaded two photos of some nice clouds from two different events. They're on the same thread.

[cycloneye]

Afternoon Discussion by NWS San Juan

Weather is improving here as the old front is lifting northward and drier air arrives.This rain event was big enough to make the record books for San Juan in January.

http://forecast.weather.gov/product.php ... glossary=1


AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
253 PM AST SAT JAN 16 2010

.SYNOPSIS...STATIONARY FRONT DRAPED ACROSS PUERTO RICO WILL DISSIPATE
OVER THE NEXT 12 TO 24 HOURS. BUILDING HIGH PRESSURE ACROSS THE
ATLANTIC WILL RESULT IN STRONG TRADES ACROSS ATLANTIC WATERS AND
THE WATERS SURROUNDING THE U.S. VIRGIN ISLANDS.

&&

.DISCUSSION...SATELLITE IMAGES ARE SHOWING THE OLD BOUNDARY
LIFTING NORTHWARD. AT THIS MOMENT A MUCH DRIER AIR MASS HAVE MOVED
OVER THE CARIBBEAN WATERS. THIS DRY POCKET WILL MOVE SLOWLY OVER
THE LOCAL ISLANDS DECREASING THE CLOUD AND SHOWER COVERAGE...BUT
BEFORE THIS HAPPENS...ENOUGH HEAT FROM THE SUN AND IN COMBINATION
WITH A VERY UNSTABLE ATMOSPHERE TO GENERATE SCATTERED TO NUMEROUS
SHOWERS ACROSS THE INTERIOR...WEST AND NORTHERN PORTIONS OF PUERTO
RICO. THESE SHOWERS ARE EXPECTED TO LINGER ACROSS THE AREA THROUGH
LATE EVENING BEFORE THE DRIER AIR MASS MOVES NORTH...OVER THE ISLANDS.

A HIGH PRESSURE CENTERED OVER THE CENTRAL ATLANTIC WILL CONTINUE
TO MOVE WESTWARD...INCREASING THE PRESSURE GRADIENT ACROSS THE
LOCAL FORECAST AREA MAINLY SUNDAY MORNING THROUGH SUNDAY NIGHT.
LARGE AMOUNTS OF MOISTURE AND UNSTABLE ATMOSPHERE ARE EXPECTED TO
PREVAILED ACROSS THE REGION THROUGH AT LEAST MID WEEK.


&&

.AVIATION...PREVAILING MVFR CONDS EXPECTED ACROSS TIST...TJSJ...TJBQ
AND TJPS THROUGH AT LEAST 16/23Z...WITH BRIEF IFR CONDS POSSIBLE
MAINLY ACROSS TJSJ AND TJPS. IMPROVING CONDS...WITH PREVAILING VFR
CONDS AND VERY QUICK PASSING MVFR CONDS...EXPECTED ACROSS ALL TAF
SITES AFTER 17/02Z. LATEST EMISSIONS FROM MONTSERRAT CONTINUE TO
SPEW VA IN THE EASTERN CARIBBEAN...BUT THIS VA WILL REMAIN SOUTH OF
THE LOCAL TAF SITES IN A EASTERLY WIND FLOW OF 10-15G25KTS. IN
FACT...TJSJ 16/12Z SOUNDING INDICATED AN EASTERLY WIND FLOW...UP
TO 30 KNOTS...ALL THE WAY FROM THE SURFACE TO AROUND 15K
FEET..BECOMING WESTERLY AND STRONGER ALOFT.


&&

.MARINE...SEAS WILL CONTINUE TO DECREASE BUT WINDS ARE EXPECTED TO
INCREASE EARLY SUNDAY THEREFORE SCA CONDITIONS WILL PREVAIL
THROUGH MONDAY FOR THE ATLANTIC WATERS AND EASTERN LOCAL CARIBBEAN
WATERS.

[cycloneye]

As of 7 PM AST the new record of rainfall for January is 9.54 inches and counting until end of month

So far the numbers stand at 9.54 inches in January but there are days left for the new record to keep adding numbers if another cold front arrives before the month goes.

http://www.srh.noaa.gov/sju/?n=record100114



* As of 7 pm AST, January 16, 2010

[cycloneye]

Good morning to all.Some showers will affect Puerto Rico today to keep adding to the January rainfall record.

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
406 AM AST SUN JAN 17 2010

.SYNOPSIS...STATIONARY FRONT DRAPED ACROSS THE AREA WILL DISSIPATE
LATER TODAY. MID-UPPER LEVEL RIDGING WILL DOMINATE THROUGH MUCH OF
THE NEW WORK WEEK AND PROMOTE A SIG DRYING TREND ACROSS THE AREA.

&&

.DISCUSSION...MODELS HANG ON TO LOTS OF CLOUDS AND MOISTURE
ESPECIALLY IN THE EAST SO ANTICIPATE ANOTHER SHOWERY DAY BUT WITH
A FEW MORE BREAKS THAN YESTERDAY ESPECIALLY ACROSS SOUTHWEST PR.
HOWEVER...DID BACK OFF ON THE AMOUNT OF QPF IN GRIDS AS SHOWERS
THIS MORNING HAVE BEEN RATHER UNIMPRESSIVE WITH JUST A FEW
HUNDREDTHS REPORTED. WINDS SOMEWHAT OF CONCERN ACROSS HIGHER ELEVS
AS NEW 06Z NAM SHOWS WINDS INCREASING UP TO 35-KT AT 3KFT LATER
TODAY WHILE THE GFS SHOWS 20-25 KT WINDS AT THAT SAME LEVEL. NAM
WINDS SEEM TOO STRONG AND WILL DISREGARD FOR NOW UNTIL GET MORE
OBS FROM MORNING RAOB AND AMDAR DATA. BUT COULD SEE A WIND
ADVISORY ISSUED FOR THE HIGHER ELEVS ABOVE 2KFT.

THINGS DRY OUT QUICKLY TONIGHT AND REMAIN DRY THROUGH WED AS MID-
UPPER LEVEL RIDGE AMPLIFIES ACROSS THE REGION. KEPT POPS ISOLD AT
BEST DURING THIS TIME FRAME WITH EVEN SOME PERIODS OF NO WX AND POPS.
MOISTURE BEGINS TO INCREASE AGAIN FOR THU AS RIDGE FLATTENS DUE TO
AN APPROACHING UPPER LVL TROUGH FROM THE U.S.

&&

.AVIATION...PREVAILING VFR CONDITIONS WILL CONTINUE ACROSS THE LOCAL
ISLANDS AND AT ALL LOCAL TAF SITES TODAY. HOWEVER...EXPECT MVFR
CONDITIONS AND LOCAL MOUNTAIN OBSCURATIONS TO CONTINUE IN SCATTERED
TO NUMEROUS PASSING SHOWERS...ESPECIALLY OVER THE INTERIOR AND NORTH
SECTIONS OF PUERTO RICO. PLUME OF VOLCANIC ASH AND STEAM WILL
CONTINUE TO SPREAD WEST TO WEST NORTHWEST TODAY AND IS FORECAST TO
AFFECT THE LOCAL CARIBBEAN COASTAL WATERS...BUT IS EXPECTED TO
REMAIN MAINLY SOUTH OF THE LOCAL ISLANDS.


&&

.MARINE...6-8 FT EASTERLY WIND WAVES AND FRESH TRADES EXPECTED
ACROSS THE ATLC WATERS. A NEW ROUND OF NNE SWELLS WILL ALSO BE
ARRIVING LATER TODAY ACROSS THE LOCAL ATLC WATERS. CONDITIONS WILL
BEGIN TO IMPROVE LATE MONDAY.

[cycloneye]

Afternoon Discussion by NWS San Juan

http://forecast.weather.gov/product.php ... glossary=1


AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
243 PM AST SUN JAN 17 2010

.SYNOPSIS...A NEARLY STATIONARY FRONT DRAPED ACROSS PUERTO RICO
WILL DISSIPATE LATER TONIGHT. BUILDING HIGH PRESSURE ACROSS THE
CENTRAL ATLANTIC WILL RESULT IN STRONG WINDS ACROSS THE REGION.

&&

.DISCUSSION...ISOLATED TO SCATTERED SHOWERS CONTINUED TO AFFECT
THE EASTERN HALF AND NORTHWEST PORTIONS OF PUERTO RICO. MOST OF
THE SHOWERS HAVE BEEN LIGHT TO MODERATE WITH THE EXCEPTION OF
SHOWERS OVER THE NORTHWEST PORTIONS OF PUERTO RICO...THESE SHOWERS
GENERATED MODERATE TO HEAVY RAINFALL. ALTHOUGH SHOWERS WILL
CONTINUE TO AFFECT THESE AREA THROUGH THE EVENING HOURS...SHOWERS
WILL BECOME MORE LESS FREQUENT THROUGH MONDAY MORNING. MONDAY WILL
BE A TRANSITION DAY WITH A FEW SHOWERS DEVELOPING ACROSS THE
ISLANDS MAINLY DURING THE AFTERNOON HOURS. IS NOT UNTIL TUESDAY
WHEN A SIGNIFICANT DECREASE ON CLOUD AND SHOWER COVERAGE WILL OCCUR.

THIS FAIR WEATHER WILL LAST THROUGH AT LEAST THURSDAY AS A MID
LEVEL TROUGH MOVES FROM THE EAST. THIS WEATHER FEATURE WILL
ENHANCED SHOWERS DEVELOPMENT ACROSS THE AREA.


&&

.AVIATION...MOSTLY VFR CONDITIONS WILL CONTINUE ACROSS MOST OF THE
LOCAL ISLANDS AND LOCAL TAF SITES THIS EVENING. HOWEVER...EXPECT
BRIEF PERIODS OF MVFR CONDITIONS AND LOCAL MOUNTAIN OBSCURATIONS IN
SCATTERED PASSING SHOWERS TO CONTINUE...ESPECIALLY ACROSS
TISX...TIST AND TJSJ UNTIL 18/00Z. PLUME OF VOLCANIC ASH AND STEAM
WILL CONTINUE TO SPREAD WEST TO WEST NORTHWEST THIS EVENING AND IS
FORECAST TO AFFECT THE LOCAL CARIBBEAN COASTAL WATERS...BUT IS
EXPECTED TO REMAIN MAINLY SOUTH OF THE LOCAL ISLANDS AND TAF SITES.
IN FACT...17/12Z SOUNDING INDICATED AN EAST NORTHEAST WIND FLOW UP
TO 20 KNOTS ALL THE WAY FROM THE SURFACE TO 20K FEET...BECOMING
NORTHWESTERLY AND STRONGER ALOFT.


&&

.MARINE...A SIGNIFICANT INCREASE IS FORECAST FOR THIS EVENING
ACROSS THE EASTERN CARIBBEAN AND ATLANTIC WATERS. THESE WINDS WILL
GENERATE DANGEROUS CHOPPY CONDITIONS ACROSS THE LOCAL
WATERS...MAINLY USVI ADJACENT WATERS AND ANEGADA PASSAGE.

[cycloneye]

Discussion Update by NWS San Juan

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
841 PM AST SUN JAN 17 2010

.UPDATE...MINOR UPDATES THIS EVENING TO PINPOINT TIMING OF PRECIP
BAND AS IS MOVES THROUGH THE AREA. NAM AND GFS IN GOOD AGREEMENT
PLACING LOW LEVEL RIDGE OVER NORTHERN COASTAL WATERS AND
CONVERGENT AXIS INITIALIZED PARTICULARLY WELL BY NAM12. H700 RIDGE
TO LIMP SLOWLY WESTWARD OVER FORECAST AREA THROUGH 24 HOURS WHICH
WILL SLOWLY FORCE MOISTURE AXIS WEST AS IT CONTINUE TO DISSIPATE.
RESULT BEING CLOUDINESS SLOWLY BREAKING UP FROM EAST TO WEST AND
SHOWER ACTIVITY FOLLOWING THAT PATTERN. MOISTURE WONT BE
COMPLETELY GONE FROM REGION UNTIL TUESDAY. UNTIL THEN...NUMEROUS
SHOWERS OVER MOST OF EASTERN PR THIS EVENING...WITH SHOWERS
TAPERING OFF AND FOCUSING OVER THE SURROUNDING WATERS OVERNIGHT.
MONDAY DAY WILL BE ANOTHER SLIGHT IMPROVEMENT FROM SUNDAY...BUT
STILL ENOUGH MOISTURE AROUND WITH WEAK 700 LEVEL FLOW BEHIND
CONVERGENCE AXIS TO KEEP SCT RANGE POPS OVER CENTRAL PR DURING THE
DAY. VI SHOULD BEGIN CLEARING OUT TONIGHT...AND HAVE A BETTER DAY TOMORROW.


&&

.AVIATION...PREVAILING VFR WITH TEMPO MVFR/IFR CONDS EXPECTED AT
LOCAL TAF SITES AS LEAST UNTIL 18/12Z...AS BKN-OVC LYR OF LOW TO MID
LVL CLDS ASSOCIATED WITH LINGERING FRONTAL BOUNDARY REMAINS HUNG UP
ACROSS THE LOCAL FLYING AREA. LOW RAGGED SCUD LIKE CLDS/CIGS WILL
CONTINUE TO OBSCURE MT TOPS...AND MAY ALSO BRIEFLY CAUSE MVFR/IFR
CONDS ENROUTE TO LOCAL TAF SITES. LATEST TJSJ 18/00Z UPPER AIR
SOUNDING INDICATED PREVAILING SOUTHEAST WIND FLOW WITH MAX WNDS OF
20-32 KTS BTW 009-060 KFT THEN DECREASING WITH HEIGHT ABV...TO NR
200 KFT. ONGOING VA EMISSIONS CONTINUED AT TRPG BUT UNABLE TO DETECT
PRESENCE OF VA ACROSS FLYING AREA DUE TO CLDS... HOWEVER LAST PIREP
RECD THIS EVENING REPORTED VA 20 MILES S OF TJPS BTW 090-100 KFT.

[cycloneye]

Good morning to all.One more day of rain for Puerto Rico.The January rainfall record keeps adding numbers.

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE SAN JUAN PR
657 AM AST MON JAN 18 2010

.SYNOPSIS...MID-UPPER LEVEL RIDGING WILL BUILD OVER THE REGION
TONIGHT AND BRING A DRYING TREND THROUGH WED. RIDGE WILL FLATTEN
LATER ON THU AS A MID-UPPER LEVEL TROUGH APPROACHES FROM THE WEST.

&&

.DISCUSSION...ONE MORE WET DAY BEFORE THINGS DRY OUT TONIGHT.
SFC TROUGH REMNANTS OF OLD FRONTAL BDRY CONTINUES TO GENERATE
SHRAS ACROSS PR THIS MORNING. BY TONIGHT...MID UPPER LEVEL HIGH
CENTERED SOUTH OF HISPANIOLA WILL MOVE EAST AND SETTLE ACROSS PR
ON TUE. THIS WILL CREATE A STRONG SUBSIDENT PATTERN ACROSS THE
ISLAND THAT SHOULD SHUT DOWN PRECIP AND BRING US MUCH NEEDED
RELIEF TO THE WET WEATHER. THIS SHOULD LAST THROUGH WED.
RIDGE/SUBSIDENCE CAP BEGINS TO FLATTEN/WEAKEN ON THU AS BROAD
UPPER LEVEL TROUGH MOVES ACROSS THE ATLC. MODELS SHOW INCREASING
MOISTURE THU-FRI SO HAVE RAISED POPS IN THU-FRI TIME FRAME.

&&

.AVIATION...REVAILING VFR CONDITIONS WILL CONTINUE ACROSS THE
LOCAL ISLANDS AND AT ALL LOCAL TAF SITES TODAY. HOWEVER...EXPECT
BRIEF MVFR CONDITIONS AND LOCAL MOUNTAIN OBSCURATIONS TO CONTINUE
IN SCATTERED TO NUMEROUS PASSING SHOWERS...ESPECIALLY OVER THE
INTERIOR AND NORTH SECTIONS OF PUERTO RICO. ANY VOLCANIC ASH AND
STEAM FROM MONTSERRAT IS EXPECTED TO MOVE GENERALLY WEST TODAY AND
SHOULD AGAIN REMAIN MAINLY SOUTH OF THE LOCAL ISLANDS.

&&

.MARINE...A COMBINATION OF MODERATE NNE SWELLS AND EASTERLY WIND
WAVES IS GENERATING SEAS OF 6-8 FT ACROSS THE ATLC WATERS. SEAS
DROP BELOW SCA CRITERIA TONIGHT AS PRES GRADIENT RELAXES AND
SWELLS SUBSIDE.

&&

.CLIMATE...THROUGH 7 AM TODAY 10.08 INCHES OF RAIN HAVE ALREADY
FALLEN AT SJU LMM INTL AIRPORT THIS MONTH. THE PREVIOUS JANUARY
RECORD WAS IN 1977 WHEN 7.60 INCHES WERE RECORDED.

THROUGH THE FIRST 17 DAYS...JANUARY 2010 RANKS FIRST AS HAVING
THE MOST RAINFALL WITH 1998 RANKED SECOND WITH 7.24 INCHES.

[cycloneye]

Afternoon Discussion by NWS San Juan

Looks like good weather returns to Puerto Rico at least until next thursday after the rainy last few days.

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
226 PM AST MON JAN 18 2010

.SYNOPSIS....MID-UPPER LEVEL RIDGING WILL CONTINUE BUILD OVER THE
REGION TONIGHT AND BRING A DRYING TREND THROUGH WED. RIDGE WILL
FLATTEN LATER ON THU AS A MID-UPPER LEVEL TROUGH APPROACHES FROM
THE WEST.

&&

.DISCUSSION...VARIABLY TO CLOUDY CONDITIONS CONTINUED TO AFFECT
THE LOCAL REGION. ISOLATED TO SCATTERED SHOWERS DEVELOPED OVER THE
NORTHWEST PORTIONS OF PUERTO RICO THIS AFTERNOON...MOST OF THESE
SHOWERS ARE EXPECTED TO DISSIPATE LATER THIS EVENING.

SATELLITE IMAGES ARE SHOWING A MUCH DRIER AIR MASS OVER THE LOCAL
EASTERN AND CARIBBEAN WATERS. THIS AIR MASS IT IS EXPECTED TO MOVE
WEST OVER THE LOCAL AREA...LIMITING THE SHOWER ACTIVITY ACROSS THE
LOCAL ARE THROUGH AT LEAST THURSDAY. INCREASING LOW LEVEL MOISTURE
AND A MID LEVEL TROUGH WILL COMBINE TO INCREASE THE SHOWER AND
CLOUD COVERAGE ACROSS THE LOCAL FORECAST AREA.

&&

.AVIATION...BRIEF PERIODS OF MVFR CONDITIONS ARE POSSIBLE ACROSS
TJMZ...AND TJBQ AT LEAST THROUGH 18/23Z. ELSEWHERE...VFR CONDITIONS
WILL PREVAIL AT LEAST THROUGH 19/12Z.

&&

.MARINE...SEAS WILL CONTINUE TO RELAX AS WINDS HAVE DECREASED IN
THE LAST 12 HOURS. NO MAJOR SWELL EVENTS ARE EXPECTED ACROSS OUR
LOCAL WATERS THROUGH AT LEAST SUNDAY.

[cycloneye]

Updated discussion by NWS San Juan

http://forecast.weather.gov/product.php ... glossary=1

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
932 PM AST MON JAN 18 2010

.UPDATE...HAVE UPDATED GRIDS FOR CLEARING SKIES AND INCREASED SOME
POPS FOR LATER PERIODS WHERE MOISTURE WILL BE PRESENT. GOOD
INDICATION OF A FRONTAL PASSAGE SUNDAY NIGHT THAT WILL END THE
SHOWERS TO BE BEGINNING ON WEDNESDAY.

&&

.DISCUSSION...CLOUDS AND SHOWERS ARE CLEARING OFF OF PUERTO RICO JUST
AS THEY DID EARLIER FOR THE U.S. VIRGIN ISLANDS. THE AIR ABOVE THE
LOCAL AREA WILL BECOME GRADUALLY DRIER THROUGH 20/00Z. AT THAT
TIME PATCHES OF MOISTURE NOW EAST OF THE WINDWARD ISLANDS WILL
MOVE INTO THE CARIBBEAN AND OVER PUERTO RICO AND THE U.S. VIRGIN
ISLANDS AND AIDED BY A SHORT WAVE TROUGH TO FOLLOW ON THURSDAY AT
UPPER LEVELS. ACCORDING TO THE GFS...THIS MOISTURE SHOULD CONTINUE
IN SIMILAR QUANTITIES UNTIL A FRONT FROM THE NORTH PASSES THROUGH
SUNDAY NIGHT AND CLEARS THE AIR. NEVERTHELESS SHOWERS WILL BE
IMPEDED BY SHALLOW MOISTURE AND WEAK DYNAMICS IN THE UPPER AIR SO
THAT WIDESPREAD HEAVY RAIN IS NOT FORESEEN. FURTHER SHOWERS WILL
NOT OCCUR AT ONE LOCATION OR AREA DURING THE PERIOD AS WINDS WILL
SHIFT TO A MORE SOUTHERLY ORIENTATION UNTIL THE FRONTAL
PASSAGE...AT WHICH TIME THEY ARE EXPECTED TO REVERSE AND BECOME
MORE NORTHERLY.


&&

.AVIATION...
VFR CONDITIONS ALL SITES NEXT 24 HOURS. ANY VA EMISSIONS FROM
MONTSERRAT TO STAY WELL SOUTH AND EAST OF LOCAL AREA AT LEAST
THROUGH 24 HOURS.

[cycloneye]

Afternoon Discussion by NWS San Juan

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
221 PM AST TUE JAN 19 2010

.SYNOPSIS...MID UPPER LEVEL HIGH PRESSURE WILL SETTLE ACROSS PUERTO RICO
THROUGH AT LEAST THURSDAY. HIGH PRESSURE WILL COLLAPSE LATER IN
THE WEEK AS AN UPPER LEVEL TROUGH ESTABLISHES ACROSS THE WESTERN
ATLANTIC.

&&

.DISCUSSION...DRY AND STABLE CONDITIONS LIMITED THE SHOWER
DEVELOPMENT ACROSS THE LOCAL FORECAST AREA. ALTHOUGH NOT MUCH
WEATHER ACTIVITY HAVE BEEN REPORTED BY THE RADAR BUT SATELLITE IMAGES
ARE SHOWING AN AREA OF INCREASING CLOUDS AND VERY ISOLATED SHOWERS
OVER THE SOUTHWEST PORTIONS OF PUERTO RICO. THESE SHOWERS WILL
DISSIPATE BEFORE SUNSET AND NO SIGNIFICANT RAINFALL IS EXPECTED.

INCREASING MOISTURE MOVING FROM THE SOUTHEAST WILL COMBINE WITH A
PRE-FRONTAL TROUGH...THIS WILL INCREASE THE SHOWERS AND CLOUD
COVERAGE FROM EARLY THURSDAY THROUGH THE INCOMING WEEKEND.

&&

.AVIATION...EXPECT PREVAILING VFR CONDITIONS ACROSS THE LOCAL
ISLANDS AND AT ALL LOCAL TAF SITES THROUGH AT LEAST 20/12Z. ANY
VOLCANIC ASH AND STEAM EMISSIONS FROM MONTSERRAT ARE EXPECTED TO
STAY WELL SOUTH AND EAST OF THE LOCAL TAF SITES.

&&

MARINE...SEAS WILL CONTINUE TO SUBSIDE THROUGH TOMORROW AND THEN
INCREASE SLIGHTLY AGAIN ON THU. OVERALL...GOOD CONDITIONS NEXT
FIVE DAYS.

[cycloneye]

Good morning to all.More rain at least this morning here.


AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
518 AM AST WED JAN 20 2010

.SYNOPSIS...
MID TO UPPER LEVEL SUBTROPICAL RIDGE EXTENDS ACROSS THE REGION FROM
THE CARIBBEAN BASIN...AND WILL REMAIN IN PLACE THROUGH TODAY...THEN
FLATTEN/WEAKEN ON THURSDAY AND FRIDAY AS A SHORT WAVE TROUGH MOVES
ACROSS THE WEST ATLANTIC AND CROSSES THE LOCAL AREA BY FRIDAY.
SURFACE HIGH PRESSURE ACROSS THE SOUTHWEST AND EAST ATLANTIC...
SEPARATED BY A DISSIPATING COLD FRONT ACROSS THE WEST CENTRAL
ATLANTIC...AND BROAD TROUGH ACROSS THE CENTRAL AND EAST CARIBBEAN...
IS HELPING TO INDUCE A WEAK SURFACE TROUGH WHICH IS NOW MOVING
ACROSS THE REGION. THIS WILL CAUSE THE LOW LEVEL WINDS TO SHIFT
FROM EAST NORTHEAST THIS MORNING TO EAST SOUTHEAST LATER IN THE
AFTERNOON.

&&

.DISCUSSION...
A SLIGHT INCREASE IN LOW LEVEL MOISTURE ACROSS THE REGION THIS
MORNING ACCOMPANYING WEAK TROUGH NOW MOVING ACROSS THE AREA.
HOWEVER...MOSTLY FAIR WEATHER SKIES IS EXPECTED TO PREVAIL DURING
THE REST OF THE DAY...WITH AFTERNOON SHOWERS FOCUSED MAINLY ACROSS
THE INTERIOR AND WEST SECTIONS OF PUERTO RICO...AS MID TO UPPER
LEVEL SUBSIDENT WILL LIMITED CONVECTIVE DEVELOPMENT. SOME OF THE
VIRGIN ISLANDS WILL CONTINUE TO EXPERIENCE SOME PASSING MORNING
SHOWERS...BUT ONLY ISOLATED SHOWER ACTIVITY IS EXPECTED DURING
THE AFTERNOON.

WITH WINDS BECOMING MORE EAST SOUTHEAST ACROSS THE REGION DURING
THE AFTERNOON AND THROUGH THE REST OF THE WEEK...EXPECT THE PREVAILING
TRADES TO BRING A SURGE OF MOISTURE ASSOCIATED WITH THE REMNANTS
OF AN OLD FRONTAL BOUNDARY...ACROSS THE LESSER ANTILLES THEN OVER
THE LOCAL ISLANDS BY THURSDAY AND INTO FRIDAY. THIS IN COMBINATION
WITH SHORT WAVE TROUGH EXPECTED TO MOVE ACROSS THE REGION DURING
THE LATER PART OF THE WEEK WILL BRING ADDITIONAL MOISTURE ACROSS
THE LOCAL ISLANDS AND SURROUNDING WATERS. THEREFORE...EXPECT A
BETTER CHANCE FOR ENHANCED SHOWER ACTIVITY ACROSS THE LOCAL
ISLANDS ON THURSDAY AND POSSIBLY INTO FRIDAY...WITH A DRIER
WEATHER PATTERN NOW EXPECTED FOR THE UPCOMING WEEKEND.

&&

.AVIATION...EXPECT PREVAILING VFR CONDITIONS ACROSS MOST OF THE
LOCAL ISLANDS AND LOCAL TAF SITES THROUGH AT LEAST 20/16Z. SOME MVFR
DUE TO CIGS WILL BE POSSIBLE ACROSS TIST AND TJSJ THROUGH AT LEAST
20/14Z AND ACROSS TNCM AND TKPK FROM 20/16Z THROUGH AT LEAST 20/22Z.
ANY VOLCANIC ASH AND STEAM EMISSIONS FROM MONTSERRAT ARE EXPECTED TO
STAY SOUTH AND EAST OF THE LOCAL TAF SITES THROUGH 20/18Z. 20/00Z
TJSJ SOUNDING...INDICATED A LIGHT EASTERLY WIND FLOW FROM THE
SURFACE ALL THE WAY TO AROUND 15K FEET...BECOMING WESTERLY BUT STILL
LIGHT ALOFT.

[cycloneye]

Afternoon Discussion by NWS San Juan

Rain returns tonight and thursday as a low level disturbance moves thru and by the way to add to the January rainfall record in San Juan.

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
141 PM AST WED JAN 20 2010

.SYNOPSIS...WEAK FRONTAL TROUGH EXTENDING FROM DOMINICAN REPUBLIC
NORTHEAST INTO ATLANTIC. WEAK LOW LEVEL TROUGH ALIGNED NORTHEAST TO
SOUTHWEST ACROSS PUERTO RICO MOVING WEST. LOW LEVEL PERTURBATION
OVER THE LEEWARD ISLANDS MOVING WEST.


&&

.DISCUSSION...AFTER A WET AND GREY MORNING SHOWERS DIMINISHED SOMEWHAT
DURING THE AFTERNOON. SKIES WILL PARTIALLY CLEAR BY MID TO LATE
AFTERNOON OVER THE EAST AND CENTRAL PART OF PUERTO RICO AND LATER
THIS EVENING OVER THE WEST. HOWEVER...THIS SHOULD BE
TEMPORARY....SINCE ANOTHER LARGE BAND OF CLOUDS AND SHOWERS IS
APPROACHING FROM THE LEEWARD ISLANDS AND APPEARS TO BE ASSOCIATED
WITH A LOW LEVEL VORTEX. LEADING EDGE OF SHOWERS COULD REACH THE
USVI THIS EVENING AND EAST PUERTO RICO AROUND MIDNIGHT. BASED ON
UPPER LEVEL PATTERN AND SOUTHWEST FLOW ALOFT WITH 50KT JET JUST
NORTH OF THE ISLANDS LATE ON THURSDAY...WOULD EXPECT A SHOWERY
PATTERN FOR THE THE USVI AND EAST HALF OF PUERTO RICO LATE TONIGHT
THROUGH THURSDAY MORNING. LOW LEVEL FLOW IS FORECAST TO BECOME
EAST SOUTHEAST ON THURSDAY WHICH SHOULD FOCUS AFTERNOON CONVECTION
MORE TOWARDS THE WEST NORTHWEST PART OF PUERTO RICO. INCREASED
SHOWER PROBABILITY TONIGHT INTO THURSDAY. I CAN NOT FORESEE
SIGNIFICANT DRYING EITHER ON FRIDAY SINCE PATTERN CONTINUES WET
AND ON SATURDAY AND SUNDAY AN APPROACHING COLD FRONT COULD TRIGGER
SOME PREFRONTAL WEATHER AHEAD OF IT.


&&

.AVIATION...EXPECT PREVAILING VFR CONDITIONS ACROSS MOST OF THE
LOCAL ISLANDS AND LOCAL TAF SITES THROUGH AT LEAST 21/06Z. BRIEF
PERIODS OF MVFR CONDITIONS WITH MOUNTAIN OBSCURATIONS ARE POSSIBLE
ACROSS TJMZ...AND TJBQ AT LEAST THROUGH 20/22Z WITH THE DEVELOPMENT
OF SHOWERS ACROSS THESE SITES...AND ACROSS TNCM AT LEAST THROUGH
21/06 WITH PASSING SHOWERS. VA AT TKPK DUE TO RECENT BULLETIN FROM
WASHINGTON VAAC AND SATELITE IMAGES...SHOWING VOLCANIC ASH AND STEAM
EMISSIONS FROM MONTSERRAT AFFECTING THIS SITE AT LEAST THROUGH
21/06Z.

[cycloneye]

The new January record rainfall total that was broken last week continues to go up and it looks like more rain is on tap for later tonight and on thursday to keep adding up.

http://www.weather.gov/climate/getclimate.php?wfo=sju

Code: Select all

WEATHER ITEM   OBSERVED TIME   RECORD YEAR NORMAL DEPARTURE LAST
                VALUE   (LST)  VALUE       VALUE  FROM      YEAR
                                                  NORMAL
..................................................................

PRECIPITATION (IN)
  TODAY            0.23          2.63 1977   0.09   0.14      T
  MONTH TO DATE   10.31                      2.03   8.28     1.19
  SINCE DEC 1     12.14                      6.60   5.54     5.77
  SINCE JAN 1     10.31                      2.03   8.28     1.19