[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 191740
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SAT MAR 19 2011

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTION 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1645 UTC.

...ITCZ...

THE ITCZ AXIS EXTENDS FROM SRN LIBERIA NEAR 5N9W ALONG 4N17W
1N26W 2N38W CROSSING THE EQUATOR INTO BRAZIL NEAR 2S47W.
CLUSTERS OF MODERATE/STRONG CONVECTION ARE POPPING UP ALONG THE
ITCZ BETWEEN 8W-17W. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS ALSO FARTHER E FROM 1N-5N BETWEEN 2W-8W. SCATTERED
MODERATE/STRONG CONVECTION IS FROM EQ-3N BETWEEN 23W-37W...AND
FROM EQ-4S BETWEEN 24W-31W.

...DISCUSSION...

GULF OF MEXICO...
THE GULF OF MEXICO CONTINUES TO BE DOMINATED BY SURFACE RIDGING
AROUND A 1024 MB HIGH CENTERED OVER MOBILE ALABAMA. THE SURFACE
RIDGE IS SUPPORTED BY AN UPPER LEVEL RIDGE MOVING INTO THE WRN
GULF WITH AXIS FROM S OF WRN MEXICO NEAR 16N105W TO JUST E OF
TEXAS AND INTO THE SE UNITED STATES. WATER VAPOR IMAGERY
INDICATES DRY AIR AND SUBSIDENCE ARE ACROSS THE BASIN SUPPORTING
MOSTLY FAIR CONDITIONS ACROSS THE AREA WITH CLEAR SKIES
THROUGHOUT BESIDES A FEW LOW CLOUDS S OF LOUISIANA. WINDS ARE
LIGHT AND VARIABLE NEAR THE HIGH PRESSURE CENTER BECOMING MAINLY
SE ACROSS THE WRN GULF REACHING UP TO 15 KTS. THE SURFACE RIDGE
IS EXPECTED TO REMAIN STATIONARY AS A FRONTAL BOUNDARY TO THE N
MOVES OVER THE W ATLC...MISSING THE GULF...ALLOWING THE RIDGE TO
BUILD NORTHWARD. THIS WILL MAINTAIN FAIR CONDITIONS ACROSS THE
BASIN FOR THE NEXT SEVERAL DAYS.

CARIBBEAN SEA...
THE CARIBBEAN IS UNDER THE INFLUENCE OF A BROAD UPPER LEVEL
RIDGE CENTERED OVER THE TROPICAL ATLC WITH ASSOCIATED DRY AIR
AND SUBSIDENCE ACROSS THE MAJORITY OF THE BASIN LIMITING DEEP
CONVECTION.  HOWEVER...A FEW TRADEWIND SHOWERS ARE NOTED IN THE
NELY TRADEWIND FLOW. IN PARTICULAR...A LINE OF SHOWERS EXTENDS
FROM S OF HAITI NEAR 18N73W TO NRN HONDURAS NEAR 15N88W.
CLOUDINESS AND POSSIBLE ISOLATED SHOWERS ARE ALSO ALONG AN ARC
2O0 NM FROM A 1009 MB LOW OVER NRN COLOMBIA NEAR 9N76W. THE
SURFACE WINDS ALSO GAIN A CYCLONIC NATURE AROUND THE COAST OF
COLOMBIA WITH STRONGER WIND SPEEDS CAUSING DAMMING AGAINST THE
COSTA RICA AND PANAMA COASTS SUPPORTING OVERCAST SKIES AND
POSSIBLE SHOWERS. ALSO...THE TAIL END OF A SURFACE TROUGH IN THE
CENTRAL ATLC IS SUPPORTING ISOLATED SHOWERS ACROSS THE WINDWARD
ISLANDS. EXPECT LITTLE CHANGE OVER THE NEXT 24 HOURS.

ATLANTIC OCEAN...
SURFACE HIGH PRESSURE ACROSS THE GULF OF MEXICO EXTENDS OVER THE
W ATLC MAINTAINING FAIR CONDITIONS W OF 60W WITH AREAS OF FAIR
WEATHER CUMULUS CLOUDS S OF 28N. AN UPPER LEVEL RIDGE IS ALONG
70W SUPPORTING THE FAIR WEATHER. ACROSS THE CENTRAL ATLC...A
SHORTWAVE UPPER TROUGH HAS NOW FORMED A CUT-OFF UPPER LOW NEAR
30N55W SUPPORTING A 1016 MB SURFACE REFLECTION LOW NEAR 29N59W
WITH A SURFACE TROUGH EXTENDING FROM IT ALONG 28N58W 25N62W.
ISOLATED SHOWERS/THUNDERSTORMS ARE ALONG THE TROUGH AXIS. A
SECOND 1014 MB SURFACE LOW IS ANALYZED NEAR 26N58W. HOWEVER...A
RECENT ASCAT SCATTEROMETER PASS INDICATES THE CENTER IS FARTHER
SE NEAR 25N52W. ELY WINDS UP TO 25 KTS ARE N OF THE LOW CENTER.
A STATIONARY FRONT EXTENDS TO THE E ALONG 26N50W 22N47W.
WIDESPREAD SHOWERS/POSSIBLE THUNDERSTORMS ARE N OF THE FRONTAL
BOUNDARY TO 30N. A SURFACE TROUGH IS ALSO S OF THE LOW CENTER
ALONG 23N52W TO 13N60W CROSSING TRINIDAD AND TOBAGO. SCATTERED
SHOWERS ARE WITHIN 60 NM EITHER SIDE OF THE TROUGH. THE
REMAINDER OF THE E ATLC IS DOMINATED BY SURFACE HIGH PRESSURE
AROUND A 1026 MB HIGH NEAR 34N42W SUPPORTING FAIR WEATHER.
ALOFT...BROAD UPPER RIDGING IS E OF THE UPPER LOW IN THE CENTRAL
ATLC ANCHORED IN THE TROPICAL ATLC NEAR 7N31W. AN UPPER LEVEL
TROUGH ALSO EXTENDS FROM THE AZORES ISLANDS TO THE CANARY
ISLANDS SUPPORTING A LOW PRESSURE SYSTEM N OF THE DISCUSSION
AREA.

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

$$
WALTON





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