[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 162348
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SAT MAY 16 2009

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS
OF SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST
FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED
ON SATELLITE IMAGERY...METEOROLOGICAL ANALYSIS...WEATHER
OBSERVATIONS...AND RADAR.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 2315 UTC.

...THE ITCZ...
THE ITCZ AXIS IS CENTERED ALONG 6N10W 3N15W 1N20W CROSSING THE
EQUATOR NEAR 23W TO NE BRAZIL NEAR 3S39W. SCATTERED MODERATE
CONVECTION IS WITHIN 30 NM OF THE AXIS BETWEEN 17W-20W.

...DISCUSSION...

THE GULF OF MEXICO...
MUCH OF THE GULF WATERS IS EXPERIENCING QUITE CONDITIONS...BUT
IT IS QUITE DIFFERENT JUST INLAND ALONG THE N GULF COAST. A COLD
FRONT OVER THE SE CONUS COMBINED WITH A DIFFLUENT PATTERN ALOFT
IS SUPPORTING WIDESPREAD SCATTERED SHOWERS AND TSTMS THERE. SOME
OF THIS UNSETTLED WEATHER IS BEGINNING TO MOVE INTO THE FAR NW
WATERS FROM 25N-27N W OF 96W JUST AHEAD OF THE FRONT. THIS FRONT
IS FORECAST TO MOVE OFFSHORE INTO THE NW GULF LATE TONIGHT THEN
TRACK SE AND WEAKEN SUN AND MON. BY MON...MANY OF THE GLOBAL
MODELS ARE SHOWING LOW PRES DEVELOP OVER CUBA OR THE SE
GULF...EITHER EXTRATROPICAL OR SUBTROPICAL...AND MOVING
GENERALLY N. ITS DEVELOPMENT AND TRACK IS UNCERTAIN BUT MODELS
ARE IN ENOUGH AGREEMENT TO WARRANT GALE HEADLINES OVER A PORTION
OF THE E AND MIDDLE WATERS FOR EARLY NEXT WEEK.

THE CARIBBEAN SEA...
A MID TO UPPER TROUGH OVER THE WRN CARIBBEAN IS PRODUCING
SCATTERED SHOWERS AND TSTMS N OF 17N BETWEEN 75W-84W. LIGHTNING
DATA SHOWS THE GREATEST CONCENTRATION OF STRIKES OVER CUBA...AS
LOCAL SEABREEZE/TERRAIN EFFECTS ARE PROVIDING ENHANCED LIFT.
LATEST VIS/SHORTWAVE IR IMAGES SHOW CYCLONIC ROTATION IN THE MID
LEVEL CLOUDS ALONG 79W JUST S OF CUBA. THIS FEATURE MAY BUILD
CLOSER TO THE SFC OVER THE NEXT COUPLE OF DAYS AND DRIFT
GENERALLY NWD...CONTINUING THE THREAT FOR TSTMS OVER THIS AREA.
STRONG SWLY UPPER FLOW ON THE E SIDE OF THE AFOREMENTIONED
TROUGH IS ADVECTING MOISTURE ACROSS THE LESSER ANTILLES. THIS
FLOW COMBINED WITH A LOW-LEVEL TROUGH A COUPLE HUNDRED NM E OF
THE AREA IS GENERATING SCATTERED SHOWERS ACROSS MUCH OF THE E
CARIBBEAN. MEANWHILE...HIGH PRES JUST NW OF BERMUDA IS
MAINTAINING 15-20 KT TRADES ACROSS THE MUCH OF THE AREA E OF
76W. THESE WINDS ARE EXPECTED TO REMAIN SIMILAR OR SLACKEN
SLIGHTLY AS THE HIGH WEAKENS IN PLACE OVER THE NEXT DAY OR TWO.

THE ATLANTIC OCEAN...
AN OCCLUDED 1007 MB LOW IS QUASI-STATIONARY ALONG THE N BORDER
OF THE DISCUSSION ZONE NEAR 32N53W. A COLD FRONT EXTENDS FROM
31N48W TO 23N54W CONTINUING SW TO 21N62W. ASSOCIATED SCATTERED
SHOWERS AND TSTMS ARE MAINLY CONFINED TO THE E SEMICIRCLE OF THE
LOW N OF 30N BETWEEN 45W AND 51W. DEEP LAYER RIDGING W OF THE
LOW IS PROVIDING MAINLY FAIR WEATHER ACROSS MUCH OF THE W ATLC.
HOWEVER...THERE ARE SCATTERED SHOWERS AND TSTMS OVER CUBA AND
NEARBY WATERS. SEE CARIBBEAN SECTION FOR MORE DETAILS. THE TIGHT
PRESSURE GRADIENT BETWEEN THE LOW AND HIGH PRES NEAR BERMUDA IS
GENERATING A SWATH OF NLY GALE FORCE WINDS JUST N OF THE
ZONE...WHICH IS SPREADING NLY SWELL TO THE NE CARIBBEAN. A WEAK
SFC TROUGH IS LOCATED JUST E OF THE FRONT FROM 23N52W TO 19N58W
PRODUCING SCATTERED SHOWERS AND ISOLATED TSTMS WITHIN 240 NM OF
THE AXIS. SFC HIGH PRES RIDGING AND MAINLY ZONAL FLOW ALOFT
DOMINATES MUCH OF THE E ATLC...SUPPORTING MAINLY FAIR WEATHER.

$$
CANGIALOSI





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