[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 032355
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT FRI AUG 03 2012

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...WEATHER OBSERVATIONS...RADAR...AND
METEOROLOGICAL ANALYSIS.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2345 UTC.

...SPECIAL FEATURES...

TROPICAL STORM ERNESTO WAS CENTERED NEAR 13.9N 64.1W AT 03/2100Z
OR ABOUT 210 MI...335 KM W OF ST. LUCIA AND 340 MI...545 KM SSE
OF SAN JUAN PUERTO RICO MOVING W AT 18 KT. ESTIMATED MINIMUM
CENTRAL PRESSURE IS 1002 MB. MAXIMUM WIND SPEED IS 45 KT WITH
GUSTS TO 55 KT. PLEASE SEE LATEST NHC FORECAST/ADVISORY UNDER
AWIPS/WMO HEADERS MIATCMAT5/WTNT25 KNHC AND THE PUBLIC ADVISORY
MIATCPAT5/WTNT35 KNHC FOR MORE DETAILS. SCATTERED MODERATE TO
HEAVY SHOWERS AND THUNDERSTORMS COVER THE ERN CARIBBEAN E OF 67W
TO OVER THE LESSER ANTILLES S OF 18N W OF 59W.

A 1006 MB LOW PRESSURE SYSTEM IS LOCATED IN THE ERN ATLC NEAR
13N26W. THIS SYSTEM IS EMBEDDED IN A TROPICAL WAVE EXTENDING
FROM 18N24W TO THE LOW LEVEL CENTER...FOUND WITHIN A BROAD
REGION OF DEEP MOISTURE ASSOCIATED WITH THE MONSOONAL GYRE
DESCRIBED BELOW. CLUSTERS OF MODERATE TO HEAVY SHOWERS AND
THUNDERSTORMS ARE FROM 7N-14N BETWEEN 24W-31W. THE OVERALL
ACTIVITY HAS BECOME MORE ORGANIZED AROUND THE LOW TODAY...AND IF
CURRENT TRENDS CONTINUE...ADVISORIES COULD BE INITIATED LATER
THIS EVENING. ALTHOUGH ENVIRONMENTAL CONDITIONS ARE CURRENTLY
CONDUCIVE FOR TROPICAL CYCLONE FORMATION...DRY AIR AND COOLER
WATERS COULD INHIBIT FURTHER DEVELOPMENT IN A DAY OR TWO. THIS
SYSTEM HAS A HIGH CHANCE OF BECOMING A TROPICAL CYCLONE DURING
THE NEXT 48 HOURS AS IT MOVES WEST-NORTHWESTWARD AT ABOUT 13 KT.

...TROPICAL WAVES...

TROPICAL WAVE MOVES ACROSS THE CENTRAL TROPICAL ATLC...ANALYZED
FROM 14N39W TO THE MONSOON TROUGH AXIS NEAR 7N41W MOVING W NEAR
10 KT. WAVE IS ALONG THE LEADING EDGE OF A SURGE OF DEEP
MOISTURE DEPICTED ON THE TOTAL PRECIPITABLE WATER IMAGERY. DRY
AIR AND SAHARAN DUST ALOFT SURROUND THIS WAVE ALLOWING FOR ONLY
SCATTERED WEAK CONVECTION WITHIN 120 NM ON EITHER SIDE OF THE
WAVE AXIS.

TROPICAL WAVE PREVIOUSLY MOVING ACROSS THE YUCATAN PENINSULA AND
CENTRAL AMERICA IS NOW OVER ERN PACIFIC WATERS. FOR MORE
INFORMATION ON THIS WAVE SEE EAST PACIFIC TROPICAL WEATHER
DISCUSSION UNDER WMO HEADER AXPZ20 KNHC 032113 TWDEP.

...THE ITCZ/THE MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS INLAND PORTIONS OF WEST AFRICA
ENTERING THE ERN TROPICAL ATLC ALONG THE COAST OF MAURITANIA
NEAR 21N17W CONTINUING WSW ALONG THE SPECIAL FEATURE LOW NEAR
13N26W TO JUST S OF CENTRAL ATLC TROPICAL WAVE NEAR 7N41W TO
6N46W...WHERE THE ITCZ AXIS CONTINUES TO 8N58W. SCATTERED WEAK
TO MODERATE CONVECTION IS WITHIN 40 NM ON EITHER SIDE OF THE
MONSOON TROUGH AND ITCZ E OF 50W. CLUSTERS OF MODERATE TO HEAVY
SHOWERS AND THUNDERSTORMS ARE FROM 7N-14N BETWEEN 24W-31W...
ASSOCIATED TO THE SPECIAL FEATURE LOW EMBEDDED IN THE MONSOONAL
GYRE.

...DISCUSSION...

GULF OF MEXICO...
NE FLOW ALOFT CONTINUES TO DOMINATE THE UPPER LEVELS OF THE
ATMOSPHERE ACROSS THE DISCUSSION AREA...AROUND THE BROAD OMEGA
UPPER RIDGE ANCHORED OVER CENTRAL TEXAS. THIS UPPER LEVEL FLOW
IS PUSHING SOME WEAK MID LEVEL ENERGY TO THE SRN CONUS STATES
PROVIDING SOME ISOLATED SHOWERS AND POSSIBLE THUNDERSTORMS N OF
24N E BETWEEN 84W-90W. THE REMAINDER OF THE GULF IS DOMINATED BY
SUBSIDENT DRY AIR ALOFT ASSOCIATED WITH THE UPPER RIDGE. THIS IS
KEEPING FAIR WEATHER CONDITIONS ELSEWHERE ACROSS THE AREA.
MODERATE CONVECTION WILL BEGIN TO ENTER THE FAR ERN GULF...AS A
VIGOROUS SURFACE TROUGH CURRENTLY OVER THE NW BAHAMAS DRIFTS WNW
OVER FLORIDA DURING THE NEXT 24-48 HOURS.

CARIBBEAN SEA...
A BROAD AREA OF SCATTERED MODERATE TO HEAVY SHOWERS AND
THUNDERSTORMS IS NOTED ON SATELLITE IMAGERY MOVING ACROSS THE
ERN CARIBBEAN E OF 67W...ASSOCIATED TO TROPICAL STORM ERNESTO.
THIS SYSTEM WILL CONTINUE TO SPREAD STRONG CONVECTION ACROSS THE
ERN AND CENTRAL CARIBBEAN DURING THE NEXT 24 HOURS. SIMILAR
ACTIVITY IS MORE SPREAD OVER THE FAR SW BASIN S OF 11N W OF
75W...RELATED TO THE MONSOON TROUGH EXTENDING FROM NRN COLOMBIA
TO COSTA RICA. THE ACTIVITY ON THIS REGION IS EXPECTED TO LINGER
DURING THE NEXT 24 HOURS. THE BASE OF A NARROW UPPER LEVEL
TROUGH EXTENDS ACROSS THE NW CARIBBEAN SUPPORTING A FEW ISOLATED
SHOWERS W OF 80W N OF 14N. OTHERWISE...DRY AIR ALOFT COVERS THE
REMAINDER OF THE CARIBBEAN SUPPRESSING DEEP CONVECTION ELSEWHERE
ACROSS THE AREA.

ATLANTIC OCEAN...
A NARROW UPPER TROUGH CONTINUES TO HOLD ITS PLACE OVER THE FAR
WRN ATLC...SUPPORTING A SLOW MOVING 1013 MB LOW EMBEDDED IN A
SURFACE TROUGH ANALYZED FROM 31N76W ACROSS THE NW BAHAMAS TO THE
LOW LEVEL CENTER NEAR 25N79W ENDING NEAR THE COAST OF CUBA NEAR
23N80W. THIS SYSTEM IS GENERATING A BROAD AREA OF SCATTERED
MODERATE TO HEAVY SHOWERS AND THUNDERSTORMS S OF 32N W OF 72W TO
ACROSS OVER THE FLORIDA PENINSULA. SHORT RANGE COMPUTER MODELS
SUGGEST THIS SYSTEM WILL CONTINUE TO SLOWLY DRIFT WNW OVER THE
NEXT 24 HOURS WITH CONTINUOUS CONVECTION AFFECTING THE COASTAL
WATERS OF FLORIDA AND NW BAHAMAS. DUE TO THE SLOW MOVEMENT OF
THIS SYSTEM...SOME LOCAL COASTAL AND INLAND FLOODING IS LIKELY
OVER FLORIDA AND THE NW BAHAMAS DURING THE FORECAST PERIOD. A
SECOND BUT MUCH WEAKER SURFACE TROUGH IS ANALYZED FROM 30N56W TO
25N61W...GENERATING SCATTERED SHOWERS WITHIN 120 NM E OF THE
TROUGH AXIS. OTHERWISE...BROAD SURFACE RIDGING DOMINATES THE
REMAINDER OF THE ATLC BASIN. METEOSAT-9 SATELLITE IMAGERY
CONTINUES TO SHOW SAHARAN DUST COVERING MOST OF THE ATLC BASIN.

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$

GARCIA




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