[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 102343
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT MON OCT 10 2011

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

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

...TROPICAL WAVES...

TROPICAL WAVE IS ANALYZED FROM 10N62W TO 19N57W MOVING W AT
5-10 KT. TOTAL PRECIPITABLE WATER IMAGERY SHOWS A POLEWARD
EXTENSION OF LOW-LEVEL MOISTURE IN THE VICINITY OF THE WAVE AXIS
BETWEEN 58W-62W. NO SIGNIFICANT DEEP CONVECTION IS NOTED WITH
THE WAVE AT THIS TIME.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 13N17W TO
09N20W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM
09N20W TO 08N29W TO 06N43W. SCATTERED MODERATE CONVECTION IS
FROM 07N-12N BETWEEN 11W-19W. ISOLATED MODERATE CONVECTION IS
FROM 04N-10N BETWEEN 30W-44W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL LOW IS CENTERED OVER THE WESTERN FLORIDA
PENINSULA NEAR 30N87W WHICH EXTENDS A NEGATIVELY TILTED TROUGH
AXIS SOUTHEASTWARD OVER THE EASTERN GULF WATERS AND THE FLORIDA
STRAITS INTO THE NW CARIBBEAN SEA SOUTH OF CUBA NEAR 20N77W.
WHILE MOST OF THE ACTIVE WEATHER AND CONVECTION IS EAST OF THIS
UPPER LEVEL TROUGH AXIS...THE UPPER LEVEL FEATURE SUPPORTS A
1005 MB LOW CENTERED OVER NORTHERN FLORIDA NEAR 30N84W AND A
SURFACE TROUGH WHICH EXTENDS FROM THE LOW ACROSS THE EASTERN
GULF ALONG 27N84W TO 24N90W. LOW-LEVEL CONVERGENCE AND OVERALL
MIDDLE TO UPPER LEVEL LIFTING DYNAMICS ARE PROVIDING FOR
ISOLATED SHOWERS AND TSTMS N OF 25N E OF THE SURFACE TROUGH AND
ACROSS PORTIONS OF THE FLORIDA PENINSULA THIS EVENING. A
WESTWARD EXTENSION OF THE SURFACE TROUGHING IS ANALYZED FROM
25N90W TO 27N95W WITH ISOLATED SHOWERS AND TSTMS OCCURRING
WITHIN 120 NM NORTH OF THE SURFACE TROUGH BOUNDARY. AN EARLIER
MORNING ASCAT PASS DEPICTED STRONGER NE WINDS IN THE RANGE OF 15
TO 20 KT BEHIND THIS FEATURE. FINALLY...CONDITIONS REMAIN QUIET
ACROSS THE SW GULF THIS EVENING AS PRIMARILY LIGHT NORTHERLY
WINDS DOMINATE UNDER FAIR SKIES.

CARIBBEAN SEA...
THE UPPER LEVEL LOW AND ASSOCIATED TROUGH AXIS OVER THE EASTERN
GULF OF MEXICO EXTENDS TO A BASE OVER THE CENTRAL CARIBBEAN NEAR
16N76W. THIS UPPER LEVEL TROUGH IS SUPPORTING A WEAK SURFACE
TROUGH EXTENDING FROM 15N76W TO 20N80W. VISIBLE SATELLITE
IMAGERY APPEARS TO INDICATE POSSIBLE WEAK CYCLOGENESIS WITH
GLOBAL MODEL DATA AND STREAMLINE ANALYSIS ALOFT INDICATING AT A
MINIMUM THAT A LOW TO MID-LEVEL CIRCULATION IS APPARENT. GIVEN
THE LOW-LEVEL MOISTURE CONVERGENCE NORTHEAST OF THIS BOUNDARY...
SCATTERED SHOWERS AND TSTMS ARE OCCURRING N 15N BETWEEN
71W-77W...INCLUDING THE WINDWARD PASSAGE REGION. SW OF THIS
AREA...THE MONSOON TROUGH CIRCULATION CROSSES NICARAGUA ALONG
13N INTO THE SW CARIBBEAN TO NEAR 13N80W. ISOLATED SHOWERS AND
TSTMS ARE OCCURRING S OF 15N W OF 76W...INCLUDING INLAND
PORTIONS OF PANAMA...COSTA RICA...AND COASTAL NICARAGUA. ACROSS
THE FAR EASTERN CARIBBEAN...A TROPICAL WAVE IS SLOWLY MOVING
WESTWARD ACROSS THE LESSER ANTILLES WITH INCREASED LOW-LEVEL
MOISTURE IN PLACE E OF 62W. ISOLATED SHOWERS WILL CONTINUE TO BE
POSSIBLE THROUGH THE OVERNIGHT HOURS OVER THE LESSER ANTILLES AS
THE WAVE PROGRESSES WESTWARD. IN ADDITION...DRY NORTHERLY UPPER
LEVEL FLOW IS PROVIDING FOR A RELATIVELY DRY AIRMASS ALOFT AND
THEREFORE NO DEEP CONVECTION IS EXPECTED WITH THE TROPICAL WAVE.

ATLANTIC OCEAN...
AN UPPER LEVEL LOW AND ASSOCIATED TROUGH OVER THE EASTERN GULF
OF MEXICO IS PROVIDING FOR A LARGE AREA OF DIFFLUENT FLOW ALOFT
ACROSS THE SW NORTH ATLC THIS EVENING. THIS IS HELPING SUPPORT A
1005 MB LOW CENTERED OVER NORTHERN FLORIDA NEAR 30N84W WHICH
CONTINUES TO DRAW LOW TO MIDDLE LEVEL MOISTURE NORTHWARD W OF
66W. SCATTERED SHOWERS AND TSTMS ARE OCCURRING FROM THE NORTH-
CENTRAL CARIBBEAN SEA WATERS ACROSS THE WINDWARD PASSAGE REGION
STRETCHING TO THE OUTER BANKS OF NORTH CAROLINA REMAINING MOSTLY
W OF 70W. SOME OF THE MORE INTENSE ACTIVITY IS LOCATED OVER THE
SE BAHAMAS AND ADJACENT COASTAL WATERS THIS EVENING FROM 20N-25N
BETWEEN 73W-76W. FARTHER EAST...AN UPPER LEVEL TROUGH CONTINUES
TO SWEEP SOUTHEASTWARD ACROSS THE CENTRAL ATLC IN SUPPORT OF A
STATIONARY FRONT ANALYZED INTO THE DISCUSSION AREA NEAR 32N35W.
THE FRONT CONTINUES SW ALONG 27N40W TO 23N50W TO 22N62W. A WIDE
AREA OF SCATTERED SHOWERS AND ISOLATED TSTMS ARE WITHIN 180 NM
OF A LINE FROM 32N35W TO 25N45W TO 20N57W. THE REMAINDER OF THE
EASTERN ATLC IS UNDER THE INFLUENCE OF A WEAK SURFACE RIDGE
EXTENDING FROM THE MADEIRA ISLANDS NEAR 33N17W TO 25N34W...AND
WEAK SURFACE TROUGHING LOCATED BETWEEN THE CANARY ISLANDS AND
CAPE VERDE ISLANDS. NO SIGNIFICANT WEATHER IS APPARENT AT THIS
TIME WITH THE SURFACE TROUGHING DUE TO GENERALLY WESTERLY WINDS
ALOFT AND A FAIR AMOUNT OF DUST PRESENT OVER THE EASTERN ATLC.

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

$$
HUFFMAN




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