[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 210535
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT MON MAR 21 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...ITCZ...

SOUTHWEST AND NORTHWEST MONSOON FLOW CONVERGENCE IS OBSERVED
FROM THE SOUTHERN COAST OF LIBERIA NEAR 4N8W TO ABOUT 2N21W. THE
ITCZ AXIS IS ANALYZED FROM THAT POINT WESTWARD ALONG 1N30W EQ40W
INTO BRAZIL NEAR 2S46W DEPICTING CONVENTIONAL CONVERGENT WIND
FLOW. WIDELY SCATTERED MODERATE CONVECTION IS FOUND WITHIN 180
NM ON EITHER SIDE OF THE AXIS E OF 40W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL RIDGE COVERS THE GULF OF MEXICO THIS EVENING...
EXTENDING ITS AXIS DOWN ACROSS THE ERN UNITED STATES INTO NE
FLORIDA AND ACROSS THE GULF TO THE BAY OF CAMPECHE. THIS FEATURE
ALONG WITH VERY DRY AIR AND STRONG SUBSIDENCE ALOFT IS PROVIDING
FAIR WEATHER CONDITIONS ACROSS THE AREA. WINDS ARE LIGHT AND
VARIABLE OVER THE FAR NE BASIN...WITH MODERATE TO FRESH EASTERLY
WINDS W OF 86W S OF 28N AND SOUTHEASTERLY RETURN FLOW N OF 25N W
OF 90W. THE SURFACE RIDGE IS EXPECTED TO REMAIN STATIONARY
MAINTAINING FAIR CONDITIONS ACROSS THE BASIN FOR THE NEXT
SEVERAL DAYS.

CARIBBEAN SEA...
THE CARIBBEAN IS UNDER THE INFLUENCE OF A BROAD UPPER LEVEL
RIDGE WITH ASSOCIATED DRY AIR AND STRONG SUBSIDENCE ACROSS THE
MAJORITY OF THE BASIN...ESPECIALLY OVER THE NW BASIN. THIS
SCENARIO IS LIMITING DEEP CONVECTION ACROSS THE AREA...LEAVING
JUST A FEW AREAS OF WEAK SHOWERS SCATTERED ACROSS THE REGION.
THESE AREAS OF SHOWERS ARE MOVING WITH THE NE FRESH TO STRONG
TRADE WIND FLOW. THIS FLOW ALSO GAIN A CYCLONIC TENDENCY AROUND
THE COAST OF COLOMBIA WITH WINDS REACHING UP TO 25 KT...CAUSING
OROGRAPHIC SHOWER ACTIVITY ALONG THE EAST COASTS EASTERN PANAMA
AND COLOMBIA S OF 11N BETWEEN 74W-78W. COMPUTER MODELS SUGGEST
SOME WEAK CONVECTION DEVELOPING OVER THE FAR SE BASIN IN WITHIN
THE NEXT 24 HOURS...WITH NO OTHER SIGNIFICANT CHANGES EXPECTED
DURING THE FORECAST PERIOD.

ATLANTIC OCEAN...
A COLD FRONT IS PUSHING FURTHER SOUTHWARD INTO THE WEST ATLC
ANALYZED ALONG 32N52W 26N60W 24N70W 25N77W. THE FRONT IS
SUPPORTED ALOFT BY AN UPPER TROUGH MOVING ACROSS THE NW ATLC N
OF THE AREA. SCATTERED SHOWERS ARE FOUND ALONG THE FRONTAL
BOUNDARY WITH ISOLATED SHOWERS UP TO 50 NM BEHIND THE FRONT. AN
EARLIER ASCAT SCATTEROMETER PASS INDICATED NORTHERLY GUSTY WINDS
UP TO 25 KTS BEHIND THE FRONT. THE REMAINDER OF THE W ATLC IS
EXPERIENCING FAIR WEATHER DUE TO AN UPPER LEVEL RIDGE COVERING
THE FAR WEST ATLC. AHEAD OF THE COLD FRONT...A VERY WEAK CUT-OFF
UPPER LOW SPINS NEAR 26N44W. THIS FEATURE SUPPORTS A 1007 MB
SURFACE REFLECTION LOW NEAR 27N48W. A SURFACE TROUGH EXTENDS S
AROUND THE EASTERN SEMI-CIRCLE OF THE LOW CENTER ALONG 23N45W TO
17N48W. THE COMBINATION OF THESE FEATURES ALONG WITH THE UPPER
LEVEL SUPPORT IS GENERATING SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS FROM 17N TO N OF THE DISCUSSION AREA BETWEEN
37W-47W. THIS SYSTEM IS EXPECTED TO CONTINUE TO TRACK NE OUT OF
THE AREA OVER THE NEXT 24 HOURS. THE REMAINDER OF THE CENTRAL
AND E ATLC IS DOMINATED BY A 1021 MB HIGH NEAR 32N36W SUPPORTING
FAIR WEATHER ACROSS THE AREA E OF 37W.


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

$$

GARCIA




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