[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 242352
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SAT APR 24 2010

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

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC...

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 8N13W 3N20W 2N40W AND INTO NE BRAZIL
NEAR THE EQUATOR AND 49W. SCATTERED MODERATE CONVECTION IS FROM
3N-6N BETWEEN 7W-13W. SIMILAR CONVECTION IS WITHIN 90 NM EITHER
SIDE OF THE AXIS BETWEEN 25W-33W AND FROM 1N-5N BETWEEN 37W-46W.

...DISCUSSION...

GULF OF MEXICO...
WATER VAPOR IMAGERY SHOWS A VIGOROUS UPPER LEVEL NEGATIVELY
TILTED TROUGH ACROSS THE MID-MISSISSIPPI RIVER VALLEY THAT
SUPPORTS A COLD FRONT ENTERING THE GULF OF MEXICO NEAR CAILLOU
BAY LOUISIANA AND EXTENDS S-SW ALONG 25N93W TO 22N96W BECOMING
STATIONARY TO MEXICO NEAR 21N97W. SCATTERED SHOWERS AND ISOLATED
TSTMS ARE OCCURRING WITHIN 120 NM EAST OF THE FRONT. EAST OF THE
FRONT ACROSS THE REMAINDER OF THE GULF...INCLUDING THE FLORIDA
PENINSULA...MAINLY SOUTHERLY FLOW DOMINATES WITH FAIRLY MOIST
AND HUMID CONDITIONS THIS EVENING AS DEWPOINTS ARE IN THE RANGE
OF MID 60S TO LOWER 70S. WEST OF THE FRONT...A WEAK RIDGE IS IN
PLACE ACROSS THE NW GULF...CENTERED NEAR BROWNSVILLE TEXAS. THIS
RIDGE IS EXPECTED TO SUSTAIN WEAK ANTICYCLONIC FLOW OVER THE NW
GULF UNTIL EARLY TUESDAY WHEN THE NEXT COLD FRONT IS FORECAST TO
CLIP THE NW GULF WATERS.

CARIBBEAN SEA...
AN UPPER LEVEL RIDGE COVERS THE WESTERN CARIBBEAN W OF 68W WITH
THE CENTER OF ANTICYCLONIC CIRCULATION OVER EASTERN HONDURAS
NEAR 15N85W. THIS DOME OF HIGH PRESSURE ALOFT IS SUPPORTING
STABLE AND MODERATELY DRY AIR OVER THE WESTERN CARIBBEAN GIVING
WAY TO GENERALLY CLEAR SKIES THIS EVENING. E TO SE SURFACE WINDS
UP TO 20 KT WERE OBSERVED ON EARLIER WINDSAT AND ASCAT PASSES W
OF 77W. THE REMAINDER OF THE CARIBBEAN IS UNDER THE INFLUENCE OF
AN UPPER LEVEL TROUGH WITH AXIS EXTENDING FROM THE CENTRAL ATLC
ALONG 20N62W TO NORTHERN VENEZUELA NEAR 11N67W. THIS UPPER LEVEL
TROUGH SUPPORTS THE REMNANTS OF AN OLD FRONTAL BOUNDARY...NOW
ANALYZED AS A SHEAR LINE THROUGH THE ANEGADA PASSAGE TO SE
PUERTO RICO NEAR 18N66W TO 17N70W. ISOLATED SHOWERS ARE
REMAINING N OF 16N AND E OF 70W...INCLUDING PORTIONS OF
HISPANIOLA. GLOBAL COMPUTER MODELS INDICATE THE ACTIVITY IN THIS
REGION MAY LINGER THROUGH EARLY SUNDAY UNTIL SURFACE HIGH
PRESSURE TAKES HOLD OVER A MAJORITY OF THE SW NORTH ATLC.

ATLANTIC OCEAN...
A SURFACE RIDGE COVERS THE WESTERN ATLC ANCHORED BY A 1020 MB
HIGH CENTERED NE OF THE BAHAMAS NEAR 28N72W. THIS FEATURE IS
RESULTING IN GENERALLY FAIR WEATHER N OF 20N W OF 62W.
HOWEVER...A FEW ISOLATED SHOWERS ARE ALONG THE GEORGIA AND SOUTH
CAROLINA COAST N OF 31N IN ASSOCIATION WITH A STATIONARY FRONTAL
BOUNDARY NORTH OF THE DISCUSSION AREA. FARTHER EAST...AN UPPER
LEVEL LOW WELL NORTH OF THE REGION ACROSS THE CENTRAL ATLC IS
RESPONSIBLE FOR A SET OF FRONTAL BOUNDARIES THAT EXTEND S OF
32N. THE EASTERNMOST FRONT ENTERS AS A DISSIPATING STATIONARY
BOUNDARY NEAR 31N38W AND EXTENDS SW ALONG 25N44W TO 20N57W THEN
CONTINUES AS A SHEAR LINE INTO THE NE CARIBBEAN SEA THROUGH THE
ANEGADA PASSAGE. SCATTERED SHOWERS ARE WITHIN 240 NM EAST OF THE
FRONT N OF 24N WHILE ISOLATED SHOWERS ARE WITHIN 120 NM EITHER
SIDE OF THE BOUNDARY S OF 24N. THE SECOND FRONT...A COLD FRONT
EXTENDS FROM 31N45W TO 23N58W WITH A DEFINED LOW-LEVEL CLOUD
LINE EVIDENT ON THE LAST FEW VISIBLE SATELLITE IMAGES OF THE
DAY. ISOLATED SHOWERS ARE WITHIN 60 NM EITHER SIDE OF THE FRONT.
THIS FRONT IS EXPECTED TO BE REINFORCED FROM THE NW AS ANOTHER
BOUNDARY EXTENDS FROM 32N51W TO 29N60W AND IS LARGELY SUPPORTED
BY THE UPPER LEVEL TROUGHING ACROSS THE CENTRAL ATLC. AN
ENHANCED WIND FIELD FOLLOWS IN THE WAKE OF THIS THIRD FRONT WITH
WINDS TO GALE FORCE N OF 29N W OF THE FRONT TO 62W. THE
REMAINDER OF THE EASTERN ATLC IS UNDER THE INFLUENCE OF AN
SURFACE RIDGE ANCHORED BY A 1019 MB HIGH CENTERED NEAR 25N25W.
HOWEVER...EMBEDDED WITHIN THE SURFACE RIDGE A WEAK AREA OF LOWER
PRESSURE IS CENTERED NEAR 31N23W THAT EXTENDS A WEAKENING COLD
FRONT ALONG 31N22W 28N24W TO 26N28W. ISOLATED SHOWERS ARE WITHIN
45 NM EITHER SIDE OF THE FRONTAL BOUNDARY.

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

$$
HUFFMAN




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