[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 211738
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...ITCZ...

ITCZ AXIS IS ANALYZED ALONG 5N5W 1N16W 2N25W 1N40W CROSSING 49W
INTO SOUTH AMERICA. SCATTERED MODERATE/STRONG CONVECTION IS
WITHIN 75/90 NM EITHER SIDE OF THE ITCZ BETWEEN 32W-39W.
CLUSTERS OF SIMILAR CONVECTION ARE WITHIN 90 NM OF THE ITCZ E OF
23W TO INLAND OVER SW AFRICA.

...DISCUSSION...

GULF OF MEXICO...
BROAD UPPER RIDGE COVERS THE GULF OF MEXICO ANCHORED IN THE W
BAY OF CAMPECHE WITH THE AXIS EXTENDING N OVER THE CENTRAL PLAIN
STATES GIVING THE GULF NW TO N FLOW ALOFT. STRONG SUBSIDENCE AND
DRY STABLE AIR ALOFT ALSO DOMINATES MUCH OF THE GULF WITH THE
EXCEPTION OF ALONG THE COAST OF TEXAS WHERE UPPER LEVEL MOISTURE
FROM THE E PACIFIC REGION IS BEING DRAWN ACROSS MEXICO AND
TEXAS. DENSE MULTILAYERED CLOUDS WITH POSSIBLE ISOLATED SHOWERS
ARE INLAND OVER TEXAS. ANOTHER EXCEPTION ARE SCATTERED SHOWERS
IN THE THE STRAITS OF FLORIDA S OF 25N BETWEEN 81W-83W
ASSOCIATED WITH THE DISSIPATING FRONTAL BOUNDARY THAT IS
CURRENTLY ACROSS THE MIDDLE KEYS. A SURFACE RIDGE COVERS THE
REMAINDER OF THE GULF ANCHORED OVER BY A 1029 MB HIGH OVER SOUTH
CAROLINA AND A 10 31 MB HIGH IN THE NW ATLC GIVING THE REMAINDER
OF THE GULF FAIR WEATHER THIS AFTERNOON. SURFACE RIDGE WILL
REMAIN IN CONTROL OF THE GULF THROUGH TUE WITH THE PRESSURE
GRADIENT RELAXING SOMEWHAT TUE NIGHT THROUGH THE END OF THE
WEEK.

CARIBBEAN SEA...
THE UPPER RIDGE OVER THE GULF OF MEXICO COVERS THE NW CARIBBEAN
GIVING THE AREA N TO NE WINDS ALOFT WITH STRONG SUBSIDENCE AND
DRY STABLE AIR ALOFT W OF A LINE FROM HISPANIOLA TO NE
NICARAGUA. A LARGE UPPER RIDGE ANCHORED OVER THE DEEP TROPICS
COVERS THE REMAINDER OF THE CARIBBEAN GIVING THE AREA E OF THE
ABOVE LINE SW TO W FLOW ALOFT. THE TIGHT PRESSURE GRADIENT OVER
THE CARIBBEAN IS BEING GENERATED BY THE SURFACE RIDGE OVER THE
GULF OF MEXICO AND THE W ATLC AND THE LOWER PRESSURE OVER THE
TROPICS TO PRODUCE STRONG NE TRADE WINDS ACROSS THE BASIN WITH
THE STRONGEST WINDS ALONG THE COAST OF COLOMBIA. LOW LEVEL
MOISTURE REMAINS ACROSS THE CARIBBEAN GENERATING PATCHES OF
SCATTERED SHOWERS USHERED IN ON THE TRADE WINDS MAINLY W OF LINE
FROM E CUBA TO NW HONDURAS. THE SURFACE RIDGE OVER THE GULF OF
MEXICO AND W ATLC WILL MAINTAIN STRONG NE TRADE WINDS ACROSS
AREA THROUGH THU RELAXING SOME OVER THE N WATERS ON FRI.

ATLANTIC OCEAN...
A SURFACE RIDGE DOMINATES THE W ATLC INTO THE GULF OF MEXICO
ANCHORED BY A 1031 MB HIGH ABOUT 300 NM NW OF BERMUDA AND A 1029
MB HIGH OVER SOUTH CAROLINA. BROAD UPPER TROUGH COVERS THE W
ATLC N OF 22N W OF 45W SUPPORTING A WELL DEFINED COLD FRONT THAT
ENTERS THE REGION NEAR 32N47W EXTENDING ALONG 23N60W TO THE
BAHAMAS NEAR 24N76W WHERE IT BEGINS TO DISSIPATE TO OVER THE
MIDDLE FLORIDA KEYS. SCATTERED SHOWERS ARE WITHIN 60 NM OF THE
FRONT WITH COLD AIR STRATOCUMULUS CLOUDS N AND W OF THE FRONT
OVER THE REMAINDER OF THE W ATLC. A WEAKENING 1008 MB LOW IS
JUST TO THE E OF THE FRONT NEAR 28N47W WITH A SURFACE TROUGH
THAT EXTENDS ALONG 22N45W TO 13N51W. A SHARP UPPER RIDGE IS TO
THE E OF THIS SURFACE TROUGH ENHANCING SCATTERED SHOWERS WITHIN
250 NM E OF THE SURFACE TROUGH MAINLY N OF 20N. A WEAK SURFACE
RIDGE DOMINATES THE E ATLC ANCHORED BY A 1020 MB HIGH E OF THE
CANARY ISLANDS NEAR 27N27W LEAVING THE REMAINDER OF THE ATLC
FAIR WEATHER THIS AFTERNOON. THE W ATLC COLD FRONT WILL
DISSIPATE OVER THE CENTRAL ATLC THROUGH TUE. HIGH PRES WILL
CONTINUE TO BUILD IN WAKE OF FRONT WITH A RIDGE EXTENDING ALONG
THE N PORTION OF THE DISCUSSION AREA TUE SHIFTING SOUTHWARD ON
THU. A SECOND COLD FRONT PASS THROUGH NE ATLC TUE NIGHT AND WED.

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

$$
PAW





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