[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 081146
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST SUN NOV 08 2009

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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...SPECIAL FEATURES...

HURRICANE IDA IS CENTERED NEAR 20.8N 85.7W AT 08/1200 UTC OR
ABOUT 60 NM ENE OF COZUMEL MEXICO AND ABOUT 75 NM SSW OF THE
WESTERN TIP OF CUBA MOVING NW AT 10 KT. ESTIMATED MINIMUM
CENTRAL PRESSURE IS 983 MB. MAXIMUM SUSTAINED WIND SPEED IS 80
KT WITH GUSTS TO 100 KT. SEE LATEST NHC FORECAST/ADVISORY UNDER
AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC FOR MORE DETAILS.
NUMEROUS STRONG CONVECTION IS WITHIN A 60/75 NM RADIUS OF 20N86W
WITH SCATTERED MODERATE/ISOLATED STRONG CONVECTION COVERING THE
REMAINDER OF THE AREA FROM 20N-24N BETWEEN 80W-86W AND CLUSTERS
OF SIMILAR CONVECTION FROM 15N-25N BETWEEN 77W-88W.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 46W/47W S OF 16N MOVING W 10-15 KT. WAVE
HAS MOVED W OF THE BROAD AREA OF MAXIMUM TOTAL PRECIPITABLE
WATER VALUES BUT SATELLITE DERIVED WINDS INDICATE THE CURVATURE
OF THE WAVE AXIS. CLUSTERS OF SCATTERED MODERATE TO ISOLATED
STRONG CONVECTION COVER THE AREA FROM 10N-17N BETWEEN 40W-48W
AND IS BEING ENHANCED BY DIFFLUENCE ALOFT ON THE W SIDE OF AN
UPPER RIDGE.

TROPICAL WAVE IS ALONG 65W/66W S OF 19N MOVING W 10-15 KT. WAVE
CONTINUES MOVING BENEATH DRY UPPER LEVEL NLY FLOW THAT COVERS
THE E CARIBBEAN AND THUS NO SIGNIFICANT DEEP CONVECTION.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 10N12W 7N20W 9N44W 8N55W 10N62W.
CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE
FROM 3N-9N BETWEEN 11W-16W INCLUDING THE COAST OF W AFRICA...
FROM 2N-5N BETWEEN 36W-44W...AND FROM 6N-13N BETWEEN 29W-40W.

...DISCUSSION...

GULF OF MEXICO...
SURFACE RIDGE CONTINUES TO SHIFT EASTWARD AS IDA MOVES TOWARD
THE YUCATAN CHANNEL AND THE SE GULF WITH  A RIDGE AXIS EXTENDING
FROM A 1025 MB HIGH OVER SOUTH CAROLINA/GEORGIA BORDER W TO
CENTRAL TEXAS COVERING THE N GULF N OF 26N. THE PRESSURE
GRADIENT BETWEEN THIS SURFACE RIDGE AND HURRICANE IDA IS
PRODUCING GALE FORCE WINDS OVER THE SE GULF INCLUDING THE
STRAITS OF FLORIDA...SEE MIAHSFAT2. A SURFACE TROUGH AT 08/0900
UTC IS OVER THE SW GULF EXTENDING FROM S MEXICO NEAR 18N932W
THROUGH A 1008 MB LOW NEAR 21N95W TO 25N96W. THIS SURFACE
TROUGH/LOW ARE SUPPORTED ALOFT BY UPPER LEVEL TROUGH WITH THE
AXIS EXTENDING FROM 26N96W TO OVER S MEXICO NEAR 18N92W. THE
REMAINDER OF THE GULF IS DOMINATED BY AN UPPER RIDGE ANCHORED IN
THE CENTRAL CARIBBEAN. THE SURFACE TROUGH/LOW COUPLED WITH
DIFFLUENCE ALOFT ARE GENERATING A BROAD AREA OF SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS FROM 22N-29N W OF 88W TO THE
COAST OF MEXICO AND ISOLATED SHOWERS DOTTING THE REMAINDER OF
THE W GULF W OF 87W. MOISTURE FROM HURRICANE IDA IS BEING
ADVECTED NE AROUND THE PERIPHERY OF AN UPPER LEVEL RIDGE
NORTHWARD THROUGH THE YUCATAN CHANNEL AND ACROSS CUBA OVER THE
SE GULF WITH SCATTERED SHOWERS AND POSSIBLE ISOLATED
THUNDERSTORMS S OF 25N E OF 87W THROUGH THE STRAITS OF FLORIDA.

CARIBBEAN SEA...
THE NW CARIBBEAN SEA REMAINS UNDER THE INFLUENCE OF HURRICANE
IDA AGAIN THIS MORNING. THE CONVECTION ASSOCIATED WITH IDA IS
MOVING NORTHWARD THROUGH THE YUCATAN CHANNEL AND ACROSS W CUBA
INTO THE SE GULF OF MEXICO ON THE NORTHERN PERIPHERY OF UPPER
LEVEL HIGH ANCHORED IN THE CENTRAL CARIBBEAN NEAR 15N81W.
DIFFLUENCE ALOFT OVER THE SW CARIBBEAN IS GENERATING ISOLATED
SHOWERS/THUNDERSTORMS S OF 12N TO INLAND OVER COLOMBIA AND
PANAMA BETWEEN 74W-81W. E OF THE UPPER LEVEL HIGH IS RELATIVELY
DRY AND STABLE AIR WITH NLY UPPER LEVEL FLOW DOMINATING THE E
CARIBBEAN E OF 74W WITH ONLY ISOLATED LOW LEVEL FAST MOVING
SHOWERS BEING USHERED IN ON MODERATE/STRONG ELY TRADEWINDS.

ATLANTIC OCEAN...
A SURFACE RIDGE CONTROLS THE W ATLC N OF 25N W OF 60W ANCHORED
BY A SERIES OF SURFACE HIGHS WITH A 1025 MB HIGH INLAND OVER THE
SOUTH CAROLINA/GEORGIA BORDER AND 1027 MB HIGH NW OF BERMUDA
WELL OFF THE NORTH CAROLINA COAST AND A SECOND 1027 MB HIGH OFF
THE CANADIAN MARITIMES. FARTHER E IS A COLD FRONT THAT ENTERS
THE REGION NEAR 32N47W AND EXTENDS SW ALONG 26N54W TO 24N64W
THEN BECOMING A SURFACE TROUGH TO 23N71W. SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS ARE WITHIN 150 NM EITHER SIDE OF THE
FRONT AND WITHIN 120 NM S OF THE SURFACE TROUGH. SCATTERED
SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS ARE FROM OVER THE
BAHAMAS ACROSS CUBA AND THROUGH THE STRAITS OF FLORIDA
COMPLIMENTS OF HURRICANE IDA. THE E ATLC IS UNDER THE INFLUENCE
OF A SURFACE RIDGE ANCHORED ON A 1034 MB HIGH CENTERED JUST NE
OF THE AZORES. AN UPPER LEVEL TROUGH IS OVER THE E/CENTRAL ATLC
EXTENDING AN AXIS THROUGH 32N34W INTO THE TROPICS NEAR 12N54W
SUPPORTING A SURFACE TROUGH THAT EXTENDS FROM 30N45W TO 21N45W
GENERATING ISOLATED SHOWERS FROM 21N-28N BETWEEN 39W AND THE
SURFACE TROUGH. AN E/W UPPER RIDGE EXTENDS FROM AFRICA ALONG 11N
TO 43W. DIFFLUENCE ALOFT TO THE E OF THE TROUGH AXIS ABOVE AND
ALONG THE W EXTENT OF THE ABOVE RIDGE IS ENHANCING THE ACTIVITY
ASSOCIATED WITH THE TROPICAL WAVE ALONG 46W/47W.

$$
WALLACE



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