[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 140548
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT THU APR 14 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...

ITCZ AXIS IS ANALYZED ALONG 06N10W 02N30W CROSSING THE EQUATOR
NEAR 35W...THEN INTO NE BRAZIL NEAR 03S40W. ISOLATED MODERATE
CONVECTION IS FROM THE EQUATOR TO 05N BETWEEN THE PRIME MERIDIAN
AND 12W...AND FROM 02N-06N BETWEEN 19W-28W.

...DISCUSSION...

GULF OF MEXICO...
NW FLOW ALOFT IS ACROSS MUCH OF THE GULF DUE TO A RATHER LARGE
UPPER LEVEL ANTICYCLONIC CIRCULATION CENTERED OVER THE WEST-
CENTRAL COAST OF MEXICO NEAR 17N101W. THE RIDGE AXIS ALOFT
EXTENDS N-NE OVER THE WESTERN GULF CRESTING NEAR THE MIDDLE
MISSISSIPPI RIVER VALLEY NEAR 36N92W. WATER VAPOR IMAGERY
INDICATES AN UPPER LEVEL TROUGH OVER THE W ATLC BETWEEN 70W-80W
THAT SUPPORTS A STATIONARY FRONT ANALYZED AT 14/0300 UTC FROM
THE FLORIDA STRAITS NEAR 24N80W W-NW TO 26N90W. THIS EVENING THE
FRONT CONTINUES ON A WEAKENING TREND AND REMAINS FAIRLY BENIGN
CONVECTIVELY...HOWEVER...RECENT SHIP...BUOY...AND LAND-BASED
OBSERVATIONS INDICATE A MUCH DRIER AIRMASS IN PLACE OVER THE NE
GULF AND ACROSS MUCH OF THE FLORIDA PENINSULA AS A 1018 MB HIGH
LOCATES NEAR 29N86W. THE SURFACE RIDGE IS FORECAST TO SHIFT
SLOWLY NE OVER THE NEXT 24 HOURS AS S-SE RETURN FLOW ESTABLISHES
ITSELF ACROSS THE ENTIRE BASIN BY EARLY FRIDAY AHEAD OF THE NEXT
COLD FRONT FORECAST TO EMERGE OFF THE TEXAS GULF COAST BY LATE
FRIDAY.

CARIBBEAN SEA...
AN AMPLIFIED MIDDLE TO UPPER LEVEL TROUGH IS LOCATED OVER THE
WESTERN CARIBBEAN WITH AXIS EXTENDING FROM THE SW NORTH ATLC
NEAR 24N73W S-SW OVER THE WINDWARD PASSAGE TO WESTERN PANAMA
NEAR 08N82W. STRONG SUBSIDENCE AND DRY AIR ACCOMPANY THIS UPPER
LEVEL FEATURE AND THESE FACTORS CONTINUE TO PROVIDE OVERALL
CLEAR SKIES AND FAIR CONDITIONS FOR THE WESTERN CARIBBEAN W OF
72W. EAST OF THE TROUGH AXIS HOWEVER...MOIST SOUTHWESTERLY FLOW
IS ADVECTING MIDDLE TO UPPER LEVEL MOISTURE ACROSS THE EASTERN
CARIBBEAN AND LESSER ANTILLES. ISOLATED SHOWERS ARE POSSIBLE
THROUGH THE OVERNIGHT AND MORNING HOURS E OF 70W. A SURFACE
TROUGH CONTINUES TO DRIFT WESTWARD AND IS ANALYZED FROM SOUTHERN
HISPANIOLA NEAR 18N72W TO NORTHERN COLOMBIA NEAR 09N74W. WHILE
BECOMING MORE AND MORE EMBEDDED UNDERNEATH THE DRIEST AIR AND
SUBSIDENCE ALOFT ASSOCIATED WITH THE UPPER LEVEL TROUGH...THE
SURFACE FEATURE WILL GRADUALLY WEAKEN OVER THE NEXT 12 HOURS
WITH EASTERLY TRADES REMAINING LIGHT DUE TO A RELAXED PRESSURE
GRADIENT ACROSS THE ENTIRE BASIN.

ATLANTIC OCEAN...
A MIDDLE TO UPPER LEVEL TROUGH IS OVER THE W ATLC BETWEEN
70W-80W WHICH SUPPORTS A COLD FRONT ANALYZED INTO THE DISCUSSION
AREA NEAR 32N73W EXTENDING SW TO THE NW BAHAMAS THEN TO 24N80W
AND WESTWARD INTO THE SE GULF OF MEXICO. A LACK OF SIGNIFICANT
MOISTURE ACCOMPANIES THE FRONT WITH ONLY ISOLATED SHOWERS
OCCURRING WITHIN 60 NM EAST OF THE FRONT N OF 29N. WEAK HIGH
PRESSURE IS BUILDING IN BEHIND THE FRONT AND IS EXPECTED TO
PROVIDE LIGHT EASTERLY FLOW THROUGH EARLY FRIDAY AS THE FRONT
MOVES NE OF 30N70W. THE REMAINDER OF THE W ATLC WEST OF 50W IS
UNDER THE INFLUENCE OF A SURFACE RIDGE EXTENDING FROM EAST OF
BERMUDA NEAR 32N57W TO NORTH OF HISPANIOLA NEAR 20N70W. FARTHER
EAST...AN UPPER LEVEL LOW IS CENTERED NEAR 28N39W IN THE CENTRAL
ATLC AND CONTINUES TO SUPPORT A 1013 MB LOW CENTERED NEAR
28N42W. A SURFACE TROUGH EXTENDS FROM THE LOW ALONG 26N40W TO
21N45W THEN WESTWARD AS A SHEAR LINE TO 21N56W. WIDELY SCATTERED
SHOWERS ARE OCCURRING EAST OF THE SURFACE TROUGH FROM 23N-30N
BETWEEN 35W-42W. STRONG HIGH PRESSURE IS EXPECTED TO BUILD IN
OVER THE CENTRAL ATLC BY LATE THURSDAY AND DISSIPATE ANY
REMNANTS OF THE LOW AND SURFACE TROUGH.

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

$$
HUFFMAN


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