[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 081802
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SAT OCT 08 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...SPECIAL FEATURES...

TROPICAL STORM PHILIPPE IS CENTERED NEAR 33.2N 47.9W AT 08/1500
UTC OR ABOUT 1055 NM W OF THE AZORES ISLANDS MOVING NE AT 25 KT.
ESTIMATED MINIMUM CENTRAL PRESSURE IS 991 MB. MAXIMUM SUSTAINED
WIND SPEED IS 50 KT WITH GUSTS TO 60 KT. PHILIPPE IS EXPECTED TO
BECOME POST-TROPICAL WITHIN THE NEXT 12-24 HOURS. PLEASE SEE THE
LATEST NHC FORECAST/ADVISORY UNDER THE AWIPS/WMO HEADERS
MIATCMAT2/ WTNT22 KNHC FOR MORE DETAILS. PHILIPPE REMAINS UNDER
STRONG SW SHEAR WITH THE LOW LEVEL CENTER EXPOSED. SCATTERED
MODERATE/ ISOLATED STRONG CONVECTION IS FROM 32N-36N BETWEEN
43W-49W...AND FROM 27N-32N BETWEEN 45W-49W.

AN AREA OF BROAD SURFACE TROUGHING IS OVER THE SW N ATLC
SUPPORTING A LARGE AREA OF SHOWERS/THUNDERSTORMS ACROSS
CUBA...THE BAHAMAS...AND FLORIDA. THIS AREA LIES UNDERNEATH
DIFFLUENT FLOW ALOFT WHICH IS HELPING SUPPORT THE WIDESPREAD
ACTIVITY. GRADUAL DEVELOPMENT OF THIS AREA OF DISTURBED WEATHER
IS POSSIBLE OVER THE NEXT COUPLE OF DAYS. REGARDLESS OF
DEVELOPMENT...HEAVY RAINFALL AND GUSTY WINDS ARE EXPECTED WITH
GALE FORCE WINDS ALREADY NOTED N OF 26N W OF 65W.

...TROPICAL WAVES...

TROPICAL WAVE IS ANALYZED FROM 12N47W TO 5N49W MOVING W 15-20
KT. TOTAL PRECIPITABLE WATER IMAGERY INDICATES A SURGE OF
MOISTURE JUST E OF THE WAVE AXIS WITH MAXIMUM VALUES ALONG THE
ITCZ AXIS. NUMEROUS STRONG CONVECTION IS FROM 6N-9N BETWEEN
47W-50W...WITH SCATTERED MODERATE CONVECTION ELSEWHERE FROM
6N-12N BETWEEN 45W-52W.

...THE ITCZ/THE MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS JUST OFF THE AFRICAN COAST OF SENEGAL
FROM 15N17W TO 14N19W. THE ITCZ AXIS BEGINS NEAR 6N24W
CONTINUING ALONG 6N33W 6N40W 7N45W. SCATTERED MODERATE/ISOLATED
STRONG CONVECTION IS FROM 5N-8N BETWEEN 20W-24W. SIMILAR
ACTIVITY IS WITHIN 120 NM EITHER SIDE OF THE AXIS BETWEEN
28W-35W...AND WITHIN 200 NM EITHER SIDE OF THE AXIS BETWEEN
35W-45W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL LOW SPINNING OVER THE FLORIDA PANHANDLE AND SW
GEORGIA WITH AXIS EXTENDING SWD ALONG 85W IS PLACING SIGNIFICANT
MOISTURE AND DIFFLUENT FLOW ALOFT ACROSS THE ERN GULF AND
FLORIDA E OF 84W. AT THE SURFACE...BROAD CYCLONIC FLOW IS ACROSS
FLORIDA AND THE FAR ERN GULF WITH BROAD RIDGING ACROSS THE
REMAINDER OF THE BASIN EXTENDING FROM A PAIR OF 1034 MB HIGHS
OVER VIRGINA AND PENNSYLVANIA. A STRONG SURFACE PRESSURE
GRADIENT MAINTAINS 20-25 KT ELY WINDS ACROSS MUCH OF THE NRN AND
ERN GULF WITH HIGHER GUSTS. SLIGHTLY WEAKER ELY WINDS OF 10-15
KTS ARE ACROSS THE SRN GULF. WHILE MUCH OF THE SHOWER ACTIVITY
ASSOCIATED WITH THE UPPER TROUGH REMAINS INLAND OVER THE ERN
HALF OF THE FLORIDA PENINSULA...A LINE OF SHOWERS/THUNDERSTORMS
HAS FORMED ALONG A LINE FROM 24N82W TO 26N88W. THIS IS DUE TO
SPEED CONVERGENCE BETWEEN THE STRONGER WINDS TO THE N AND WEAKER
WINDS TO THE S. THE REMAINDER OF THE BASIN IS UNDER MOSTLY CLEAR
SKIES DUE TO DRY AIR ALOFT AROUND THE WRN SIDE OF THE UPPER
TROUGH. A FEW ISOLATED SHOWERS ARE NOTED OVER THE FAR NW GULF.
EXPECT MOIST CONDITIONS TO REMAIN ACROSS THE FLORIDA PENINSULA
AS THE UPPER LEVEL TROUGH REMAINS QUASI-STATIONARY.

CARIBBEAN SEA...
THE UPPER TROUGH OVER THE ERN GULF OF MEXICO EXTENDS OVER THE NW
CARIBBEAN SUPPORTING A SURFACE TROUGH EXTENDING FROM S OF
CENTRAL CUBA TO N OF HONDURAS NEAR 17N87W. SURFACE CONVERGENCE
COMBINED WITH UPPER LEVEL DIFFLUENCE IS SUPPORTING SCATTERED
SHOWERS/THUNDERSTORMS MAINLY E OF THE SURFACE TROUGH FROM
17N-22N BETWEEN 74W-80W. ISOLATED SHOWERS/THUNDERSTORMS ARE FROM
16N-19N BETWEEN 80W-87W. A SHORTWAVE UPPER TROUGH EXTENDS ACROSS
HAITI WHICH IS PLACING UPPER LEVEL DIFFLUENCE ACROSS THE
DOMINICAN REPUBLIC WHERE STRONG SHOWERS/THUNDERSTORMS ARE
OCCURRING FROM 15N-19N BETWEEN 68W-72W. A SMALL CLUSTER OF
STORMS IS ALSO OVER NE PUERTO RICO. A FEW SCATTERED SHOWERS ARE
OFF THE COASTS OF NICARAGUA AND COSTA RICA MOST LIKELY DUE TO
WIND CONVERGENCE AGAINST THE COAST. SOME OF THE ACTIVITY IS ALSO
INFLUENCED BY THE MONSOON TROUGH AXIS EXTENDING ACROSS COSTA
RICA TO NRN COLOMBIA/VENEZUELA. ACROSS THE ERN CARIBBEAN...AN
UPPER LEVEL RIDGE EXTENDS ALONG 64W. E OF THE UPPER RIDGE...DRY
AIR IS INFLUENCING THE LESSER ANTILLES MAINTAINING FAIR WEATHER.
EXPECT MOIST CONDITIONS TO REMAIN ACROSS THE NW AND CENTRAL
CARIBBEAN FOR THE NEXT COUPLE OF DAYS AS THE UPPER TROUGH OVER
THE WRN CARIBBEAN REMAINS QUASI-STATIONARY.

ATLANTIC OCEAN...
AN UPPER LEVEL TROUGH OVER THE ERN GULF OF MEXICO IS PLACING A
LARGE AREA OF DIFFLUENT FLOW ALOFT ACROSS THE WRN ATLC. THIS IS
HELPING SUPPORT SCATTERED SHOWERS/ISOLATED THUNDERSTORMS W OF
65W. STRONG SHOWERS/THUNDERSTORMS ARE ALSO ACROSS MUCH OF THE
ERN COAST OF THE FLORIDA PENINSULA WHERE FLOOD WATCHES ARE
CURRENTLY IN EFFECT. GUSTY CONDITIONS ARE ALSO BEING EXPERIENCED
ALONG THE ENTIRE COAST DUE TO THE STRONG PRESSURE GRADIENT
BETWEEN HIGH PRESSURE TO THE N AND LOWER PRESSURES OVER THE
CARIBBEAN. IN FACT...GALE FORCE WINDS ARE N OF 26N W OF 65W.
GUSTY AND MOIST CONDITIONS ARE EXPECTED TO REMAIN OVER THE
ENTIRE SW N ATLC FOR THE NEXT COUPLE OF DAYS. SEE SPECIAL
FEATURES FOR MORE DETAILS ON THIS AREA OF DISTURBED WEATHER.
FARTHER E...A SURFACE TROUGH EXTENDS SE OF T.S. PHILIPPE ALONG
27N53W 23N61W 23N69W. SCATTERED SHOWERS ARE WITHIN 75 NM EITHER
SIDE OF THE AXIS MERGING INTO THE LARGER AREA OF ACTIVITY OVER
THE WRN ATLC. THIS TROUGH IS SUPPORTED BY AN UPPER LEVEL TROUGH
TO THE N ALONG 53W WHICH IS ALSO CURRENTLY SHEARING APART
PHILIPPE. DIFFLUENCE BETWEEN THIS UPPER TROUGH AND AN UPPER
LEVEL RIDGE EXTENDING FROM THE ERN CARIBBEAN TO NEAR 31N43W IS
SUPPORTING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM N OF
26N BETWEEN 43W-50W. THE REMAINDER OF THE BASIN IS DOMINATED BY
BROAD SURFACE RIDGING AROUND A 1035 MB HIGH NW OF SPAIN NEAR
45N14W SUPPORTED BY A STRONG UPPER LEVEL HIGH NEAR 39N15W. AN
ELONGATED UPPER LEVEL LOW IS SANDWICHED BETWEEN THIS UPPER HIGH
AND THE RIDGE EXTENDING FROM THE CARIBBEAN TO NEAR 31N43W.

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

$$
WALTON







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