[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 110535
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT WED MAR 11 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 5N9W 1N17W CROSSING THE EQUATOR
NEAR 23W CONTINUING 1S38W 2S46W. SCATTERED MODERATE IS WITHIN
180 NM EITHER SIDE OF THE AXIS BETWEEN 15W-23W AND WITHIN 90 NM
N OF THE AXIS BETWEEN 36W-39W.

...DISCUSSION...

GULF OF MEXICO...
A MID-UPPER LEVEL RIDGE CENTERED OVER THE GULF IS BECOMING
INCREASINGLY ELONGATED DUE TO AN APPROACHING UPPER TROUGH FROM
THE W. A STREAM OF PACIFIC MOISTURE...TRANSPORTED BY A
SUBTROPICAL JET...IS BEING DRIVEN BETWEEN THE RIDGE AND TROUGH
OVER MEXICO AND INTO THE EASTERN CONUS. LITTLE OF THIS MOISTURE
IS ENTERING THE GULF...IN FACT...WATER VAPOR IMAGERY REVEALS
WIDESPREAD DRY AIR ACROSS NEARLY THE ENTIRE AREA...LEADING TO
FAIR CONDITIONS. IN THE LOW LEVELS...A WEAK HIGH PRES RIDGE LIES
OVER THE NE WATERS. THIS FEATURE IS PROVIDING LIGHT WINDS...
EXCEPT 15-20 KT E TO SE FLOW OVER THE WRN WATERS. A COLD FRONT
IS EXPECTED TO MOVE INTO THE NW GULF WED EVENING AND THEN
STALL IN THAT AREA THROUGH FRI.

CARIBBEAN SEA...
TRADE WINDS HAVE SLACKENED OVER THE PAST DAY OR TWO DUE TO A
WEAKENING HIGH PRES RIDGE OVER THE W ATLC. SFC OBS AND QSCAT
DATA SHOW THE STRONGEST FLOW...20-25 KT...OVER THE CENTRAL
CARIBBEAN WITH WINDS REACHING 30 KT NEAR THE COAST OF COLOMBIA.
LOW-LEVEL CLOUDS AND ISOLATED SHOWERS ARE SCATTERED ACROSS THE
AREA ESPECIALLY E OF 68W. IN THE MID AND UPPER LEVELS...A TROUGH
EXTENDING FROM THE SE BAHAMAS TO HONDURAS IS THE MAIN FEATURE.
CONFLUENCE ALOFT IS ENHANCING SUBSIDENCE NEAR AND W OF ITS
AXIS...WHILE DIFFLUENCE IS CAUSING ONLY SLIGHT MOISTENING E OF
THE AXIS. LITTLE CHANGE IN THE LARGE SCALE WEATHER PATTERN IS
ANTICIPATED OVER THE NEXT DAY OR SO.

ATLANTIC OCEAN...
AN OCCLUDED 996 MB LOW PRES SYSTEM CENTERED JUST N OF THE
DISCUSSION AREA NEAR 34N55W IS TRACKING SE NEAR 20 KT. AN
ASSOCIATED COLD FRONT EXTENDS FROM THE TRIPLE PT NEAR 34N52W
SOUTHWESTWARD ALONG 28N55W 26N65W 28N72W THEN STATIONARY TO THE
SOUTH CAROLINA COAST. WHILE ONLY A NARROW BAND OF LOW-LEVEL
MOISTURE IS NOTED ALONG MUCH OF THE BOUNDARY...SCATTERED SHOWERS
AND TSTMS ARE LIKELY N OF 28N WITHIN 180 NM E OF FRONT. GALE
FORCE WINDS ARE REVEALED IN THE LATEST QSCAT DATA N OF THE
FRONT E OF 63W WITH STORM CONDITIONS EVIDENT JUST N OF THE AREA.
ANOTHER LOW PRES SYSTEM CONTINUES TO PULL AWAY FROM THE AREA
CENTERED NEAR 36N38W WITH A TROUGH EXTENDING S TO 22N38W.
LINGERING EFFECTS OF THIS SYSTEM CONSIST OF SLY 20-30 KT WINDS
WITHIN 240 NM E OF THE TROUGH AND SCATTERED SHOWERS AND TSTMS N
OF 28N BETWEEN 30W-33W. IN THE DEEP TROPICS...STRONG WLY FLOW
ALOFT IS TRANSPORTING MID-HIGH LEVEL CLOUDINESS ACROSS THE
REGION. FARTHER S...AN UPPER DIFFLUENT PATTERN ON THE SW
PERIPHERY OF A RIDGE OVER AFRICA IS ENHANCING CONVECTION WITHIN
THE ITCZ.

$$
CANGIALOSI



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