Re: Caribbean - Central America Weather
Posted: Fri Jul 27, 2012 5:48 am
Good morning. We can see plenty of rain and some gusts as the wave moves thru by late Sunday thru Tuesday.
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
535 AM AST FRI JUL 27 2012
.SYNOPSIS...AT UPPER LEVELS...A TUTT WITH MULTIPLE LOWS CONTINUES
BETWEEN 20 AND 30 NORTH LATITUDE THROUGH MID WEEK NEXT WEEK.
GENERALLY HIGH PRESSURE CONTINUES OVER THE CARIBBEAN. THE TROUGH
FROM THE STRONGEST LOW NORTHEAST OF THE AREA ON FRIDAY OF NEXT
WEEK PULLS ACROSS THE FORECAST AREA ON THE FOLLOWING SUNDAY.
AT MID LEVELS...HIGH PRESSURE DOMINATES THE ATLANTIC NORTH OF THE
ISLANDS UNTIL LATE NEXT WEEK. TROUGHS MOVE THROUGH ON SATURDAY
AND TUESDAY. A REFLECTION OF THE STRONGER TUTT LOW IS NORTHEAST OF
THE AREA AND MOVES CLOSER DURING THE WEEK. ALTHOUGH SOME MOISTURE
IS SEEN SATURDAY NIGHT AND SUNDAY...BEST MOISTURE AT MID LEVELS
COMES WITH THE SECOND TROPICAL WAVE TUESDAY AND CONTINUES UNTIL
LATE NEXT WEEK.
AT LOWER LEVELS... A WEAK WAVE MOVES THROUGH TODAY FOLLOWED BY
ANOTHER WEAK TROUGH ON SUNDAY MORNING. A MUCH STRONGER TROPICAL
WAVE WILL APPROACH THE AREA ON MONDAY AND MOVE THROUGH ON TUESDAY
WITH BETTER MOISTURE THAN HAS BEEN SEEN IN SEVERAL WEEKS. MOISTURE
WILL LINGER WITH RIPPLES IN THE FLOW THROUGH FRIDAY OF NEXT WEEK.
&&
.DISCUSSION...SCATTERED SHOWERS HAVE INVADED THE SOUTHEAST HALF
OF THE FORECAST AREA AS THE FIRST LEG OF A TROPICAL WAVE MOVES
INTO THE AREA. MIMIC PRODUCT SHOWS THAT THIS LEG DEVELOPED LATE
YESTERDAY AFTERNOON AND OVERNIGHT AS THE POSITIVELY-TILTED AXIS
OF THE WAVE LOCATED NEAR 20 NORTH AND 53 WEST AT 27/07Z
APPROACHED THE LESSER ANTILLES. THE MIMIC PRODUCT ALSO SHOWS THAT
THE MOISTURE IN THE WAVE HAS SEPARATED FROM THE ITCZ TO THE SOUTH
OF IT AND IS MOVING A LITTLE FASTER THAN THE WAVE THAT ORIGINALLY
GENERATED IT. THE TWO LEGS FORMING THE INVERTED V SHAPE OF THE
WAVE SHOULD PASS THIS AFTERNOON OR EVENING AND AGAIN ON SUNDAY.
THIS IS FOLLOWED ON SUNDAY EVENING BY DRYING AT 700 MB AND THE
SURFACE. BETTER LOW- LEVEL MOISTURE MOVES IN OVERNIGHT SUNDAY
NIGHT TO HOLD SCATTERED TO NUMEROUS SHOWERS IN THE FORECAST FOR
THE USVI AND THE WINDWARD PORTION OF PUERTO RICO DESPITE LOW TO
MID LEVEL DRYING. THE SECOND WAVE ARRIVES MONDAY AROUND NOON...OR
JUST BEFORE...IN THE USVI AS A GLOBE OF MOISTURE WITH A TAIL
STREAMING BACK FROM ITS TOP. IT CROSSES INTO PUERTO RICO DURING
THE AFTERNOON AND EVENING MONDAY SPREADING SHOWERS AND SCATTERED
THUNDERSTORMS ACROSS THE AREA THROUGH TUESDAY. THE MOISTURE
"TAIL" THEN CROSSES THROUGH THE LOCAL AREA ON WEDNESDAY.
PRESENTLY SATELLITE PRODUCTS CONFIRM THE MOISTURE IN THE SECOND
WAVE AND EXPECT THAT THIS WILL NOT WEAKEN VERY MUCH AS IT
APPROACHES THE CARIBBEAN. THIS WILL BRING CLOUDIER AND WETTER
WEATHER FOR THE UPCOMING WEEK IN CONTRAST TO THE DRIER AND HAZIER
WEATHER THIS WEEK. WITH THE UPPER LEVEL LOWS AND THEIR MOISTURE
ALSO EXPECT AN INCREASE IN THUNDERSTORM ACTIVITY. SOME OF THOSE
THUNDERSTORMS WILL PRODUCE GUSTY WINDS...ESPECIALLY AS THE SECOND
WAVE ENTERS THE AREA ON MONDAY.
&&
.AVIATION...
PREVAILING VFR CONDITIONS WILL CONTINUE ACROSS THE LOCAL ISLANDS
AND AT ALL TAF SITES THROUGH AT LEAST 27/22Z. HOWEVER... BRIEF
PERIODS OF MVFR CONDITIONS WITH MOUNTAIN OBSCURATIONS CAN BE
EXPECTED THIS AFTERNOON OVER TJMZ. SURFACE WINDS WILL CONTINUE
MAINLY EAST AT 10 TO 15 KTS WITH HIGHER GUSTS.
&&
.MARINE...WINDS AND SEAS WILL DECREASE SOMEWHAT SATURDAY AND
SUNDAY...BUT INCREASE CONSIDERABLY ON MONDAY. AT THIS TIME EXPECT
PREVAILING WINDS AND SEAS TO APPROACH SMALL CRAFT ADVISORY CRITERIA
MONDAY...BUT FORECAST FALLS JUST SHORT. NEVERTHELESS
THUNDERSTORMS...ESPECIALLY THOSE ACCOMPANYING THE INVADING
TROPICAL WAVE MONDAY...WILL CONTAIN VERY GUSTY WINDS DUE TO THE
RELATIVELY DRY AIR INTO WHICH THEY ARE MOVING.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 90 79 90 79 / 10 30 30 30
STT 90 79 90 81 / 30 10 20 40
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
535 AM AST FRI JUL 27 2012
.SYNOPSIS...AT UPPER LEVELS...A TUTT WITH MULTIPLE LOWS CONTINUES
BETWEEN 20 AND 30 NORTH LATITUDE THROUGH MID WEEK NEXT WEEK.
GENERALLY HIGH PRESSURE CONTINUES OVER THE CARIBBEAN. THE TROUGH
FROM THE STRONGEST LOW NORTHEAST OF THE AREA ON FRIDAY OF NEXT
WEEK PULLS ACROSS THE FORECAST AREA ON THE FOLLOWING SUNDAY.
AT MID LEVELS...HIGH PRESSURE DOMINATES THE ATLANTIC NORTH OF THE
ISLANDS UNTIL LATE NEXT WEEK. TROUGHS MOVE THROUGH ON SATURDAY
AND TUESDAY. A REFLECTION OF THE STRONGER TUTT LOW IS NORTHEAST OF
THE AREA AND MOVES CLOSER DURING THE WEEK. ALTHOUGH SOME MOISTURE
IS SEEN SATURDAY NIGHT AND SUNDAY...BEST MOISTURE AT MID LEVELS
COMES WITH THE SECOND TROPICAL WAVE TUESDAY AND CONTINUES UNTIL
LATE NEXT WEEK.
AT LOWER LEVELS... A WEAK WAVE MOVES THROUGH TODAY FOLLOWED BY
ANOTHER WEAK TROUGH ON SUNDAY MORNING. A MUCH STRONGER TROPICAL
WAVE WILL APPROACH THE AREA ON MONDAY AND MOVE THROUGH ON TUESDAY
WITH BETTER MOISTURE THAN HAS BEEN SEEN IN SEVERAL WEEKS. MOISTURE
WILL LINGER WITH RIPPLES IN THE FLOW THROUGH FRIDAY OF NEXT WEEK.
&&
.DISCUSSION...SCATTERED SHOWERS HAVE INVADED THE SOUTHEAST HALF
OF THE FORECAST AREA AS THE FIRST LEG OF A TROPICAL WAVE MOVES
INTO THE AREA. MIMIC PRODUCT SHOWS THAT THIS LEG DEVELOPED LATE
YESTERDAY AFTERNOON AND OVERNIGHT AS THE POSITIVELY-TILTED AXIS
OF THE WAVE LOCATED NEAR 20 NORTH AND 53 WEST AT 27/07Z
APPROACHED THE LESSER ANTILLES. THE MIMIC PRODUCT ALSO SHOWS THAT
THE MOISTURE IN THE WAVE HAS SEPARATED FROM THE ITCZ TO THE SOUTH
OF IT AND IS MOVING A LITTLE FASTER THAN THE WAVE THAT ORIGINALLY
GENERATED IT. THE TWO LEGS FORMING THE INVERTED V SHAPE OF THE
WAVE SHOULD PASS THIS AFTERNOON OR EVENING AND AGAIN ON SUNDAY.
THIS IS FOLLOWED ON SUNDAY EVENING BY DRYING AT 700 MB AND THE
SURFACE. BETTER LOW- LEVEL MOISTURE MOVES IN OVERNIGHT SUNDAY
NIGHT TO HOLD SCATTERED TO NUMEROUS SHOWERS IN THE FORECAST FOR
THE USVI AND THE WINDWARD PORTION OF PUERTO RICO DESPITE LOW TO
MID LEVEL DRYING. THE SECOND WAVE ARRIVES MONDAY AROUND NOON...OR
JUST BEFORE...IN THE USVI AS A GLOBE OF MOISTURE WITH A TAIL
STREAMING BACK FROM ITS TOP. IT CROSSES INTO PUERTO RICO DURING
THE AFTERNOON AND EVENING MONDAY SPREADING SHOWERS AND SCATTERED
THUNDERSTORMS ACROSS THE AREA THROUGH TUESDAY. THE MOISTURE
"TAIL" THEN CROSSES THROUGH THE LOCAL AREA ON WEDNESDAY.
PRESENTLY SATELLITE PRODUCTS CONFIRM THE MOISTURE IN THE SECOND
WAVE AND EXPECT THAT THIS WILL NOT WEAKEN VERY MUCH AS IT
APPROACHES THE CARIBBEAN. THIS WILL BRING CLOUDIER AND WETTER
WEATHER FOR THE UPCOMING WEEK IN CONTRAST TO THE DRIER AND HAZIER
WEATHER THIS WEEK. WITH THE UPPER LEVEL LOWS AND THEIR MOISTURE
ALSO EXPECT AN INCREASE IN THUNDERSTORM ACTIVITY. SOME OF THOSE
THUNDERSTORMS WILL PRODUCE GUSTY WINDS...ESPECIALLY AS THE SECOND
WAVE ENTERS THE AREA ON MONDAY.
&&
.AVIATION...
PREVAILING VFR CONDITIONS WILL CONTINUE ACROSS THE LOCAL ISLANDS
AND AT ALL TAF SITES THROUGH AT LEAST 27/22Z. HOWEVER... BRIEF
PERIODS OF MVFR CONDITIONS WITH MOUNTAIN OBSCURATIONS CAN BE
EXPECTED THIS AFTERNOON OVER TJMZ. SURFACE WINDS WILL CONTINUE
MAINLY EAST AT 10 TO 15 KTS WITH HIGHER GUSTS.
&&
.MARINE...WINDS AND SEAS WILL DECREASE SOMEWHAT SATURDAY AND
SUNDAY...BUT INCREASE CONSIDERABLY ON MONDAY. AT THIS TIME EXPECT
PREVAILING WINDS AND SEAS TO APPROACH SMALL CRAFT ADVISORY CRITERIA
MONDAY...BUT FORECAST FALLS JUST SHORT. NEVERTHELESS
THUNDERSTORMS...ESPECIALLY THOSE ACCOMPANYING THE INVADING
TROPICAL WAVE MONDAY...WILL CONTAIN VERY GUSTY WINDS DUE TO THE
RELATIVELY DRY AIR INTO WHICH THEY ARE MOVING.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 90 79 90 79 / 10 30 30 30
STT 90 79 90 81 / 30 10 20 40