[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 082359
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...SPECIAL FEATURES...

HURRICANE IDA IS CENTERED NEAR 23.1N 86.5W AT 09/0000 UTC OR
ABOUT 120 NM WNW OF THE WESTERN TIP OF CUBA AND ABOUT 385 NM SSE
OF THE MOUTH OF THE MISSISSIPPI RIVER MOVING NNW AT 10 KT.
ESTIMATED MINIMUM CENTRAL PRESSURE IS 979 MB. MAXIMUM SUSTAINED
WIND SPEED IS 90 KT WITH GUSTS TO 110 KT. SCATTERED STRONG
CONVECTION IS LOCATED WITHIN 90 NM OF THE CENTER WITH NUMEROUS
MODERATE/ISOLATED STRONG CONVECTION ELSEWHERE FROM 17N-25N
BETWEEN 80W-85W AND FROM 23N-27N BETWEEN 85W-88W. SEE LATEST NHC
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC
FOR MORE DETAILS.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 49W S OF 18N MOVING W NEAR 15 KT. THE
WAVE HAS MOVED W OF AN UPPER LEVEL AREA OF DIFFLUENCE ACROSS THE
TROPICAL ATLC E OF 45W AND NOW RESIDES BENEATH A DRY UPPER LEVEL
TROUGH AXIS ALONG 50W. TOTAL PRECIPITABLE WATER VALUES IN THE
VICINITY OF THE WAVE AXIS HAVE LESSENED OVER THE PAST 24
HOURS...HOWEVER A BROAD AREA OF 850 MB RELATIVE VORTICITY
FOLLOWS THE WAVE S OF 15N BETWEEN 40W-50W. NO SIGNIFICANT DEEP
CONVECTION ACCOMPANIES THE WAVE.

TROPICAL WAVE IS ALONG 68W S OF 18N MOVING W NEAR 15 KT. THE
WAVE CONTINUES TO REMAIN ILL-DEFINED AND DIFFICULT TO TRACK AS
IT MOVES WESTWARD BENEATH DRY AND STABLE NNW UPPER LEVEL FLOW
LOCATED ACROSS MUCH OF THE CARIBBEAN SEA. ISOLATED SHOWERS
CONTINUE MOVING ACROSS THE BASIN ON 10-15 KT TRADEWINDS.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 10N14W 5N26W 8N48W 9N51W 8N60W.
CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS
FROM 5N-8N BETWEEN 23W-32W. SIMILAR CONVECTION IS FROM 8N-13N
BETWEEN 32W-44W AND LARGELY ENHANCED BY UPPER LEVEL DIFFLUENCE
EAST OF AN UPPER TROUGH WITH AXIS ALONG 50W.

...DISCUSSION...

GULF OF MEXICO...
HURRICANE IDA IS LOCATED IN THE SOUTHERN GULF OF MEXICO NORTH OF
THE YUCATAN CHANNEL AND REMAINS ADJACENT TO A SURFACE RIDGE
LOCATED OVER THE SE CONUS...NORTHERN FLORIDA...AND W ATLC
WATERS. CONVECTION ASSOCIATED WITH IDA REMAINS MAINLY S OF 27N E
OF 88W ENHANCED BY UPPER LEVEL DIFFLUENCE BETWEEN AN UPPER LEVEL
RIDGE EXTENDING FROM THE WESTERN CARIBBEAN NORTHWARD ACROSS CUBA
AND THE FLORIDA PENINSULA AND AN UPPER LEVEL TROUGH WITH AXIS
ALONG 92W POSITIONED TO THE WEST OF IDA. THE UPPER LEVEL TROUGH
ALSO SUPPORTS A SURFACE TROUGH THAT EXTENDS FROM NEAR
BROWNSVILLE TEXAS TO A 1008 MB LOW NEAR 23N95W THEN TO THE
WESTERN YUCATAN PENINSULA NEAR 19N91W. ASIDE FROM THE WIND SHIFT
ASSOCIATED WITH THE SURFACE TROUGH AXIS...UPPER LEVEL DIFFLUENCE
N OF 24N W OF 88W IS GENERATING SCATTERED SHOWERS AND ISOLATED
TSTMS ACROSS THE NW GULF WATERS AND INLAND OVER THE EASTERN
TEXAS AND LOUISIANA GULF COAST. WITH THE INCREASED PRESSURE
GRADIENT CREATED BETWEEN HURRICANE IDA...THE LOW OVER THE
WESTERN GULF...AND THE SURFACE RIDGE OVER THE SE CONUS...A LARGE
AREA OF EASTERLY WIND UP TO 30 KT IS LOCATED NORTH OF IDA AND
ACROSS THE NW GULF.

CARIBBEAN SEA...
AS HURRICANE IDA MOVES INTO THE SOUTHERN GULF OF MEXICO THROUGH
THE YUCATAN CHANNEL...CONVECTIVE BANDS CONTINUE TO BRING
SCATTERED SHOWERS AND TSTMS TO WESTERN AND CENTRAL CUBA AND THE
NW CARIBBEAN WATERS FROM 17N-23N BETWEEN 80W-85W. THIS ACTIVITY
IS BEING ENHANCED BY UPPER LEVEL DIFFLUENCE ASSOCIATED WITH AN
UPPER LEVEL ANTICYCLONIC CIRCULATION CENTERED IN THE SW
CARIBBEAN NEAR 13N80W. UPPER LEVEL DIFFLUENCE IS ALSO LOCATED
OVER THE SW CARIBBEAN AND IS PRODUCING SCATTERED SHOWERS AND
ISOLATED TSTMS S OF 13N BETWEEN 75W-85W. ELSEWHERE E OF 80W...
N-NW UPPER LEVEL FLOW DOMINATES OVER THE BASIN WITH PRIMARILY
MODERATE SUBSIDENCE NOTED ON WATER VAPOR IMAGERY FROM 11N-17N. A
FEW ISOLATED SHOWERS ARE MOVING WESTWARD ON 10-15 KT TRADEWINDS
IN THE VICINITY OF THE TROPICAL WAVE ALONG 68W AND N OF 17N
ACROSS HISPANIOLA...PUERTO RICO...AND THE US/UK VIRGIN ISLANDS
THIS EVENING.

ATLANTIC OCEAN...
A SURFACE RIDGE CONTROLS THE W ATLC N OF 24N W OF 60W ANCHORED
BY A 1026 MB HIGH CENTERED NORTH OF THE DISCUSSION AREA NEAR
35N74W. FARTHER EAST...A COLD FRONT ENTERS THE REGION NEAR
32N46W AND EXTENDS SW ALONG 29N50W TO 22N60W. THE FRONT IS
SUPPORTED ALOFT BY A SHARP UPPER LEVEL TROUGH WITH AXIS FROM
30N61W TO 22N66W. EAST OF THIS UPPER LEVEL TROUGH...LOW-LEVEL
CONVERGENCE NEAR THE FRONT COUPLED WITH UPPER LEVEL DIFFLUENCE
IS GENERATING A BROAD AREA OF SCATTERED SHOWERS AND ISOLATED
TSTMS WITHIN 200 NM SE OF THE FRONT AND WITHIN 300 NM NW OF THE
FRONT. AN AREA OF SCATTERED SHOWERS TRAILS WEST FROM THE TAIL
END OF THE COLD FRONT ALONG 20N BETWEEN 60W-72W. SCATTERED
SHOWERS ARE FROM HISPANIOLA...PUERTO RICO...AND THE US/UK VIRGIN
ISLANDS TO 22N. THE EASTERN ATLC IS UNDER THE INFLUENCE OF A
SURFACE RIDGE ANCHORED ON A 1030 MB HIGH CENTERED EAST OF THE
AZORES NEAR 38N21W. AN UPPER LEVEL TROUGH IS OVER THE E/CENTRAL
ATLC EXTENDING AN AXIS ALONG 50W DIPPING TO NORTHERN SOUTH
AMERICA NEAR SURINAME AND CONTINUES TO ENHANCE CONVECTION N OF
THE ITCZ AXIS FROM 9N-20N BETWEEN 32W-42W.

$$
HUFFMAN





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