TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT THU OCT 11 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1015 UTC.

…SPECIAL FEATURE…

TROPICAL WAVE IS ABOUT 350 MILES EAST-SOUTHEAST OF THE WINDWARD
ISLANDS…FROM 18N53W TO A 1007 MB SURFACE LOW AT 10N55W. THE
SYSTEM IS EXPECTED TO MOVE W-NW AT ABOUT 10 KT. THE WAVE LIES
WITHIN A LARGE AREA OF ENHANCED DEEP LAYER MOISTURE. THIS SYSTEM
HAS A MEDIUM CHANCE OF BECOMING A TROPICAL CYCLONE DURING THE
NEXT 48 HOURS. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS
FROM 9N-15N BETWEEN 44W-58W. STRONG GUSTY WINDS AND HEAVY
RAINFALL ARE POSSIBLE OVER THE LESSER ANTILLES DURING THE NEXT
FEW DAYS AS THE SYSTEM MOVES CLOSER TO THE ISLANDS. ADDITIONAL
INFORMATION ON THIS FEATURE CAN BE FOUND IN HIGH SEAS FORECASTS
ISSUED BY THE NATIONAL WEATHER SERVICE.

A 1009 MB LOW IS OVER THE W ATLANTIC NEAR 25N72W. A SURFACE
TROUGH EXTENDS FROM 29N70W TO THE LOW TO THE S BAHAMAS AT
22N73W. SCATTERED MODERATE TO STRONG CONVECTION IS FROM 24N-29N
BETWEEN 69W-73W. A TROPICAL DEPRESSION COULD FORM TODAY AND
BRIEFLY PERSIST BEFORE HOSTILE UPPER-LEVEL WINDS CAUSE RAPID
WEAKENING OF THE LOW. THIS SYSTEM HAS A MEDIUM CHANCE OF
BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS…
AS IT MOVES SOUTHWARD SLOWLY. ADDITIONAL INFORMATION ON THIS
FEATURE CAN BE FOUND IN HIGH SEAS FORECASTS ISSUED BY THE
NATIONAL WEATHER SERVICE.

…THE ITCZ/THE MONSOON TROUGH…

THE MONSOON TROUGH EXTENDS FROM THE COAST OF SENEGAL NEAR 14N15W
TO 7N20W TO 4N23W. THE ITCZ EXTENDS FROM 4N23W TO 2N40W TO 3N44W
TO N BRAZIL AT 3N51W. NO DEEP CONVECTION IS ASSOCIATED WITH THE
ITCZ/MONSOON TROUGH AT THIS TIME.

…DISCUSSION…

THE GULF OF MEXICO…
AS OF 0900 UTC…A 1026 MB HIGH IS CENTERED OVER KENTUCKY AT
38N85W. 10-15 KT EASTERLY SURFACE WINDS ARE OVER THE GULF OF
MEXICO. SCATTERED SHOWERS ARE OVER THE STRAITS OF FLORIDA…AND
W CUBA. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS OVER
THE BAY OF CAMPECHE AND S MEXICO FROM 18N-20N BETWEEN 91W-95W.
IN THE UPPER LEVELS…THE BASE OF A LARGE LONGWAVE UPPER
LEVEL TROUGH IS OVER THE GULF N OF 24N WITH STRONG SUBSIDENCE.
CONSIDERABLE UPPER LEVEL MOISTURE AND SCATTERED TO BROKEN HIGH
CLOUD IS OVER THE STRAITS OF FLORIDA…AND W CUBA. EXPECT OVER
THE NEXT 24 HOURS FOR CONVECTION TO PERSIST OVER THE BAY OF
CAMPECHE…AND THE YUCATAN PENINSULA…S GULF S OF 22N. 

THE CARIBBEAN SEA…
A LAX SURFACE PRESSURE GRADIENT IS OVER THE CARIBBEAN SEA WITH
PREDOMINATELY 10-15 KT EASTERLY WINDS. STRONGEST WINDS ARE ALONG
THE COAST OF N COLOMBIA. WIDELY SCATTERED MODERATE CONVECTION IS
OVER GUATEMALA…HONDURAS…BELIZE…AND THE NW CARIBBEAN FROM
14N-22N BETWEEN 80W-91W. ISOLATED MODERATE CONVECTION IS OVER N
COLOMBIA…PANAMA…AND THE SW CARIBBEAN FROM 9N-12N BETWEEN
74W-83W. SIMILAR CONVECTION IS OVER JAMAICA AND HAITI FROM
16N-19N BETWEEN 72W-77W. SCATTERED SHOWERS ARE OVER THE E
CARIBBEAN E OF 64W. IN THE UPPER LEVELS…AN UPPER LEVEL HIGH IS
CENTERED OVER THE GULF OF HONDURAS…WHILE NE UPPER LEVEL FLOW
IS OVER THE E CARIBBEAN. EXPECT OVER THE NEXT 24 HOURS FOR
SIMILAR CONVECTION TO BE OVER THE W CARIBBEAN AND CENTRAL
AMERICA…WHILE ADDITIONAL CONVECTION ADVECTS INTO THE E
CARIBBEAN FROM THE ATLANTIC.

THE ATLANTIC OCEAN…
A 1009 MB LOW IS OVER THE W ATLANTIC NEAR 25N72W. SEE ABOVE. A
LARGE 1027 MB HIGH IS OVER THE CENTRAL ATLANTIC NEAR 35N41W. A
LARGE AREA OF AFRICAN DUST AND DRY AIR IS OVER THE E ATLANTIC N
OF 15N E OF 38W. IN THE UPPER LEVELS…AN UPPER LEVEL LOW IS
CENTERED OVER THE CENTRAL ATLANTIC NEAR 25N34W. ISOLATED
MODERATE CONVECTION IS E OF THE CENTER FROM 23N-28N BETWEEN
25W-32W. ANOTHER UPPER LEVEL LOW IS CENTERED N OF THE LEEWARD
ISLANDS NEAR 21N64W. ISOLATED MODERATE CONVECTION IS FROM
19N-25N BETWEEN 60W-65W.