[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 120554
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT FRI OCT 12 2012

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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...SPECIAL FEATURES...

TROPICAL STORM PATTY AT 11/0300 UTC IS CENTERED NEAR 25.9N 72.5W
OR ABOUT ABOUT 260 MI...420 KM NE OF THE CENTRAL BAHAMAS.
PRESENT MOVEMENT IS STATIONARY. ESTIMATED MINIMUM CENTRAL
PRESSURE IS 1005 MB. MAXIMUM SUSTAINED WIND SPEED IS 40 KT WITH
GUSTS TO 50 KT. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO
HEADERS MIATCMAT1/WTNT21 KNHC. PATTY IS EXPECTED TO BE SHORT
LIVED TROPICAL CYCLONE DUE TO SOUTHWESTERLY SHEAR...THE PRESENCE
OF A COLD FRONT IN THE WESTERN PORTION OF THE CIRCULATION...AND
THE LIKELIHOOD OF DRIER AND MORE STABLE AIR THAT WILL ENTRAIN
INTO THE CENTER. NUMEROUS STRONG CONVECTION IS FROM 25N-28N
BETWEEN 68W-72W. SCATTERED MODERATE CONVECTION IS ELSEWHERE FROM
28N-33N BETWEEN 67W-73W.

AS OF 0300 UTC...A BROAD AREA OF LOW PRESSURE ASSOCIATED WITH A
TROPICAL WAVE IS LOCATED NEAR 13.4N 59.6W OR ABOUT 4 NM N OF
BARBADOS. SHOWER AND THUNDERSTORM ACTIVITY CONTINUES TO SHOW
SOME SIGNS OF ORGANIZATION...AND ENVIRONMENTAL CONDITIONS APPEAR
CONDUCIVE FOR GRADUAL DEVELOPMENT OVER THE NEXT COUPLE OF DAYS.
THIS SYSTEM HAS A HIGH CHANCE OF BECOMING A TROPICAL CYCLONE
DURING THE NEXT 48 HOURS AS IT MOVES NORTHWESTWARD AT 15 KT.
REGARDLESS OF DEVELOPMENT...STRONG GUSTY WINDS AND HEAVY
RAINFALL ARE POSSIBLE ACROSS PORTIONS OF THE LESSER ANTILLES
DURING THE NEXT COUPLE OF DAYS. A DIFFLUENT PATTERN ALOFT IS
OBSERVED OVER THIS SYSTEM...AND IS HELPING TO SUPPORT THE
CONVECTION ASSOCIATED WITH IT. THUNDERSTORM ACTIVITY HAS ALSO
INCREASED NEAR THE CIRCULATION CENTER. CLUSTERS OF SCATTERED
MODERATE TO ISOLATED STRONG CONVECTION ARE OVER A LARGE AREA E
OF THE CENTER FROM 8N-18N BETWEEN 45W-59W.

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

THE MONSOON TROUGH EXTENDS FROM GUINEA BISSAU AT 12N16W TO
6N26W. THE ITCZ CONTINUES FROM 6N26W TO 5N33W TO 8N40W TO
10N54W. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS
ALONG THE COAST OF W AFRICA FROM 6N-10N BETWEEN 11W-15W.
ISOLATED MODERATE CONVECTION IS N OF THE ITCZ FROM 7N-12N
BETWEEN 33W-39W.

...DISCUSSION...

GULF OF MEXICO...
AS OF 0300 UTC...A 1025 MB HIGH IS CENTERED OVER N ALABAMA AT
34N86W. 10-20 KT EASTERLY SURFACE WINDS ARE OVER THE GULF OF
MEXICO WITH STRONGEST WINDS N OF THE YUCATAN PENINSULA.
SCATTERED MODERATE TO STRONG CONVECTION IS OVER THE BAY
OF CAMPECHE AND S MEXICO FROM 17N-20N BETWEEN 91W-95W. IN THE
UPPER LEVELS...THE BASE OF AN UPPER LEVEL TROUGH IS OVER THE E
GULF AND FLORIDA E OF 87W. AN UPPER LEVEL HIGH IS CENTERED OVER
MEXICO NEAR 20N99W. STRONG SUBSIDENCE COVERS THE GULF EXCEPT
OVER THE BAY OF CAMPECHE. EXPECT OVER THE NEXT 24 HOURS FOR
CONVECTION TO PERSIST OVER THE BAY OF CAMPECHE...AND ALONG THE
COAST OF MEXICO NEAR TAMPICO.

THE CARIBBEAN SEA...
A WEAK 1007 MB LOW HAS TRAVERSED OVER BARBADOS. A CONSIDERABLE
AMOUNT OF CONVECTION IS E OF THE ISLAND. SEE ABOVE. EXPECT THE
LOW CENTER TO BE OVER THE LEEWARD ISLANDS IN 24 HOURS WITH WINDS
NEAR TROPICAL STORM FORCE N AND E OF CENTER. ELSEWHERE...THE
SURFACE PRESSURE GRADIENT IS TIGHTENING OVER THE NW CARIBBEAN
WHERE 20 KT NE WINDS ARE EXPECTED IN 12-24 HOURS. PRESENTLY
ISOLATED MODERATE CONVECTION IS OVER THE NW CARIBBEAN...E
GUATEMALA...AND W HONDURAS. SCATTERED MODERATE CONVECTION IS
OVER N COLOMBIA...PANAMA. WIDELY SCATTERED MODERATE CONVECTION
IS OVER JAMAICA...E CUBA...AND HAITI FROM 17N-21N BETWEEN
72W-78W. SCATTERED SHOWERS ARE OVER THE E CARIBBEAN E OF 70W. IN
THE UPPER LEVELS...AN UPPER LEVEL RIDGING IS OVER THE W
CARIBBEAN W OF 83W...WHILE NE UPPER LEVEL FLOW IS OVER THE
REMAINDER OF THE CARIBBEAN. EXPECT INCLEMENT WEATHER OVER THE E
CARIBBEAN OVER THE NEXT 24 HOURS...AND ALSO INCREASED CONVECTION
OVER THE SW CARIBBEAN.


THE ATLANTIC OCEAN...
T.S. PATTY IS E OF THE BAHAMAS. SEE ABOVE. A LARGE 1027 MB HIGH
IS OVER THE CENTRAL ATLANTIC NEAR 34N40W. A LARGE AREA OF
AFRICAN DUST AND DRY AIR IS OVER THE E ATLANTIC N OF 20N E OF
50W. IN THE UPPER LEVELS...AN UPPER LEVEL LOW IS CENTERED OVER
THE CENTRAL ATLANTIC NEAR 25N32W. ISOLATED MODERATE CONVECTION
IS E OF THE CENTER FROM 23N-27N BETWEEN 29W-32W. ANOTHER UPPER
LEVEL LOW IS CENTERED N OF THE LEEWARD ISLANDS NEAR 27N57W.
ISOLATED MODERATE CONVECTION IS FROM 25N-29N BETWEEN 50W-54W.

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

$$
FORMOSA






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