[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 282347
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT TUE SEP 28 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.

...SPECIAL FEATURES...

TROPICAL DEPRESSION SIXTEEN IS CENTERED NEAR 21.4N 82.0W AT
29/0000 UTC OR ABOUT 95 NM SSE OF HAVANA CUBA AND ABOUT 280 NM
SSW OF MIAMI FLORIDA MOVING NNE AT 7 KT. ESTIMATED MINIMUM
CENTRAL PRESSURE IS 997 MB. MAXIMUM SUSTAINED WIND SPEED IS 30
KT WITH GUSTS TO 40 KT. THE SYSTEM IS EXPECTED TO BRING LARGE
AMOUNTS OF RAIN TO THE CAYMAN ISLANDS...CUBA...JAMAICA...AND
SOUTHERN FLORIDA OVER THE NEXT 24-48 HOURS. THESE AREAS SHOULD
MONITOR THE SYSTEM FOR THREAT OF FLOODING AND MUDSLIDES IN
MOUNTAINOUS TERRAIN. WHILE THE SYSTEM REMAINS A BROAD AREA OF
LOWER PRESSURE ENCOMPASSING THE NW CARIBBEAN SEA...EASTERN GULF
OF MEXICO...AND FAR WESTERN ATLC...MOST OF THE SCATTERED
MODERATE TO STRONG CONVECTION IS OCCURRING WITHIN THE SOUTHERN
SEMICIRCLE OF THE LOW FROM 15N-20N BETWEEN 77W-89W. SCATTERED
MODERATE CONVECTION SPREADS NORTHWARD OVER THE EASTERN
SEMICIRCLE FROM 15N-25N BETWEEN 74W-83W AND OVER PORTIONS OF THE
NW BAHAMAS AND SOUTHERN FLORIDA DUE TO A FRONTAL BOUNDARY FROM
25N-32N BETWEEN 76W-84W. SEE LATEST NHC INTERMEDIATE PUBLIC
ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT1/WTNT31 KNHC AND THE
FULL FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21
KNHC FOR MORE DETAILS.

...TROPICAL WAVES...

TROPICAL WAVE EXTENDS FROM 08N28W TO 18N30W MOVING W AT 10-15
KT. BROAD LOW-LEVEL CYCLONIC FLOW IS NOTED ON SATELLITE IMAGERY
IN THE VICINITY OF THE WAVE AXIS S OF 16N. THE WAVE ALSO
COINCIDES WITH AN AREA OF MAXIMUM DEEP LAYER MOISTURE EVIDENT IN
TOTAL PRECIPITABLE WATER IMAGERY FROM 06N-13N BETWEEN 22W-32W.
LARGELY EMBEDDED WITHIN THE ITCZ...SCATTERED MODERATE AND
ISOLATED STRONG CONVECTION IS FROM 04N-11N BETWEEN 24W-34W.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 12N16W 10N28W 08N39W 09N51W 08N59W.
A COMPLEX OF SCATTERED MODERATE TO STRONG CONVECTION IS ALONG
THE W AFRICA COAST FROM 11N-16N BETWEEN 14W-19W. ASIDE FROM
CONVECTION ASSOCIATED WITH THE TROPICAL WAVE...A PAIR OF SURFACE
TROUGHS ARE ANALYZED OVER THE CENTRAL TROPICAL ATLC. ONE IS FROM
11N42W TO 16N41W WITH SCATTERED MODERATE CONVECTION FROM 10N-18N
BETWEEN 38W-46W. THE OTHER SURFACE TROUGH EXTENDS FROM 08N51W TO
15N48W WITH SCATTERED MODERATE CONVECTION FROM 09N-15N BETWEEN
46W-53W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL TROUGH IS LOCATED OVER THE GULF OF MEXICO AND
REMAINS N OF 21N. THIS UPPER LEVEL TROUGH SUPPORTS A COLD FRONT
THAT EXTENDS ACROSS FLORIDA FROM FLAGLER BEACH TO TAMPA BAY AND
INTO THE GULF ALONG 28N83W 25N88W 21N90W. WHILE MOST OF THE
ENERGY ASSOCIATED WITH THE MIDDLE TO UPPER LEVEL TROUGH IS NORTH
OF 24N...NUMEROUS SHOWERS AND SCATTERED TSTMS COVER A LARGE AREA
FROM 24N-30N E OF 85W...INCLUDING MUCH OF THE FLORIDA PENINSULA
THIS EVENING. WEST OF THE COLD FRONT AND S OF 21N...UPPER LEVEL
DIFFLUENCE ASSOCIATED WITH AN UPPER LEVEL RIDGE AXIS EXTENDING
FROM WEST-CENTRAL MEXICO NEAR 20N105W TO THE EASTERN YUCATAN
PENINSULA NEAR 18N88W IS SUPPORTING ISOLATED SHOWERS AND TSTMS S
OF 20N OVER SOUTHERN MEXICO AND THE BAY OF CAMPECHE.
ELSEWHERE...WEST OF THE FRONT...STRONG N TO NE SURFACE WINDS UP
TO 25 KT ARE OCCURRING AND ALONG WITH STRONG NORTH-NORTHWESTERLY
FLOW ALOFT...ARE PROVIDING FOR STRONG SUBSIDENCE AND A
RELATIVELY DRY AND STABLE AIRMASS. CONDITIONS ACROSS THE SE GULF
AND FLORIDA STRAITS ARE EXPECTED TO DETERIORATE OVER THE NEXT 24
HOURS AS T.D. SIXTEEN MOVES N-NE OVER WESTERN CUBA.

CARIBBEAN SEA...
T.D. SIXTEEN IS THE MAIN FEATURE ACROSS THE NW CARIBBEAN THIS
EVENING GENERATING NUMEROUS SHOWERS AND SCATTERED TSTMS OVER
MUCH OF THE BASIN N OF 12N BETWEEN 65W-89W. THIS WIDESPREAD AREA
OF CONVECTION IS SUPPORTED ALOFT BY AN ANTICYCLONIC CIRCULATION
CENTERED NEAR 18N75W THAT EXTENDS AN UPPER LEVEL RIDGE AXIS SE
TO NE VENEZUELA NEAR 10N62W. AS T.D. SIXTEEN IS STEERED NORTH-
NORTHEASTWARD OVER THE NEXT COUPLE OF DAYS BY THE MIDDLE TO
UPPER LEVEL TROUGHING OVER THE GULF OF MEXICO...10-15 KT E-SE
TRADEWINDS ARE EXPECTED TO RESUME OVER THE BASIN E OF 72W WITH
SURFACE TROUGHING FORECAST TO DRIFT OVER THE WESTERN CARIBBEAN
BETWEEN 80W-85W THROUGH EARLY SATURDAY.

ATLANTIC OCEAN...
A DEEP LAYER TROUGH IS LOCATED ACROSS THE EASTERN CONUS AND GULF
OF MEXICO THAT SUPPORTS A COLD FRONT ENTERING THE AREA NEAR
32N78W TO THE FLORIDA COAST NEAR 29N81W ENHANCING NUMEROUS
SHOWERS AND SCATTERED TSTMS N OF 25N W OF 76W. LOW TO MIDDLE
LEVEL MOISTURE CONTINUES TO ADVECT NORTHWARD FROM THE CARIBBEAN
SEA OVER THE GREATER ANTILLES AND SW NORTH ATLC GENERATING
SCATTERED SHOWERS AND ISOLATED TSTMS FROM 18N-25N BETWEEN
63W-73W. FARTHER EAST...TWO WEAK SURFACE LOW CIRCULATIONS ARE
ACROSS THE REMAINDER OF THE W ATLC. A 1014 MB LOW IS CENTERED
NEAR 32N66W ENHANCING ISOLATED SHOWERS WITHIN 210 NM OF THE
CENTER IN THE NW SEMICIRCLE. ANOTHER LOW AT 1016 MB IS CENTERED
NEAR 28N56W AND SUPPORTS AN AREA OF ISOLATED SHOWERS FROM
24N-29N BETWEEN 52W-57W. THESE LOWS ARE FORECAST TO GRADUALLY
DISSIPATE OVER THE NEXT 24 HOURS AND BECOMING EMBEDDED WITHIN
SURFACE RIDGING W OF 50W. A SURFACE TROUGH IS ANALYZED FROM
19N46W TO 28N41W WITH POSSIBLE SHALLOW LOW-LEVEL ISOLATED
SHOWERS FROM 24N-30N BETWEEN 39W-45W. OVER THE EASTERN ATLC...A
1017 MB LOW IS CENTERED NEAR 30N31W WITH SURFACE TROUGHING
EXTENDING NORTHWARD TO 35N33W AND SOUTHWARD TO 25N33W. ANY
POSSIBLE ISOLATED SHOWERS ARE BEING SHEARED TO THE NE DUE TO A
WEAK UPPER LEVEL SHORTWAVE TROUGH WITH AXIS ALONG 29W. THE
ISOLATED SHOWERS ARE MAINLY N OF 29N BETWEEN 25W-32W.

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

$$
HUFFMAN




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