[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 022348
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT WED OCT 02 2013

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.

...SPECIAL FEATURES...
TROPICAL STORM JERRY IS CENTERED NEAR 29.3N 42.6W AT 02/2100 UTC
OR ABOUT 940 NM W-SW OF THE AZORES MOVING NE AT 6 KT. ESTIMATED
MINIMUM CENTRAL PRESSURE IS 1009 MB. MAXIMUM SUSTAINED WIND
SPEED IS 35 KT WITH GUSTS TO 45 KT. SEE LATEST NHC FORECAST/
ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC FOR MORE
DETAILS. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE FROM 27N-
31N BETWEEN 40W-45W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS
ARE WITHIN 45 NM OF LINE FROM 25N43W TO 27N41W.

THE AREA OF INTEREST IN THE W CARIBBEAN IS ANALYZED AS A SURFACE
TROUGH THAT EXTENDS FROM THE SE GULF OF MEXICO NEAR 26N86W
THROUGH WEAK 1007 MB LOW IN THE W CARIBBEAN NEAR 19N86W TO THE
COAST OF HONDURAS NEAR 15N85W. AN AIR FORCE RESERVE UNIT
HURRICANE HUNTER AIRCRAFT HAS EXTENSIVELY INVESTIGATED THIS
BROAD AREA OF LOW PRESSURE AND DETERMINED THAT THE SYSTEM DID
NOT HAVE A WELL-DEFINED CIRCULATION. HOWEVER...THIS SYSTEM IS
PRODUCING WINDS TO GALE FORCE AND HAS THE POTENTIAL TO BECOME A
TROPICAL STORM AT ANY TIME TONIGHT OR ON THURSDAY. THE LOW IS
EXPECTED TO MOVE N-NW INTO THE S GULF OF MEXICO BY EARLY THU.
THIS SYSTEM HAS A HIGH CHANCE OF BECOMING A TROPICAL CYCLONE
DURING THE NEXT 48 HOURS. REGARDLESS OF DEVELOPMENT THIS SYSTEM
COULD PRODUCE LOCALLY HEAVY RAINS COULD AFFECT THE CAYMAN
ISLANDS...PORTIONS OF CUBA...AND PORTIONS OF THE YUCATAN
PENINSULA DURING THE NEXT DAY OR TWO. HEAVY SHOWERS WITH
EMBEDDED ISOLATED THUNDERSTORMS ARE FROM 19N-22N BETWEEN 83W-87W
WITH SCATTERED SHOWERS/ISOLATED THUNDERSTORMS DOTTING THE
REMAINDER OF W CARIBBEAN AND SE GULF OF MEXICO FROM 16N-27N
BETWEEN 80W-89W INCLUDING PORTIONS OF THE YUCATAN PENINSULA...W
CUBA...THE CAYMAN ISLANDS...AND S FLORIDA.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 17N35W TO 11N35W MOVING W AT 10-15
KT. WAVE IS EMBEDDED WITHIN A BROAD AREA OF OF RELATIVELY DEEP
MOISTURE AS DEPICTED ON THE TOTAL PRECIPITABLE WATER IMAGERY.
HOWEVER...LITTLE OR NO CURVATURE INDICATED IN THE SATELLITE
WINDS. NO ASSOCIATED CONVECTION.

TROPICAL WAVE EXTENDS FROM 21N49W TO 11N51W MOVING W NEAR 20 KT.
TOTAL PRECIPITABLE WATER IMAGERY INDICATES DRY AIR HAS INTRUDED
INTO THE WAVE LEAVING THE ONLY THE S PORTION WITH DEEP MOISTURE.
CLUSTERS OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN
180 NM W OF THE WAVE FROM 11N-13N.

...ITCZ/MONSOON TROUGH...
MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL ATLC
NEAR 13N17W ALONG 9N22W TO 8N27W WHERE THE ITCZ BEGINS AND
CONTINUES ALONG 10N40W 22N50W TO 9N57W. SCATTERED MODERATE/
ISOLATED STRONG CONVECTION IS FROM 9N-12N BETWEEN 24W-28W. AN
E/W UPPER RIDGE IS ACROSS THE TROPICAL ATLC AND IS PROVIDING
DIFFLUNCE ALOFT TO GENERATE SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS DOTTING THE AREA BETWEEN THE TROPICAL WAVES FROM
11N-22N BETWEEN 36W-45W.

...DISCUSSION...

GULF OF MEXICO...
A NARROW UPPER TROUGH EXTENDS FROM A SHORTWAVE UPPER TROUGH OVER
THE MIDDLE MISSISSIPPI VALLEY INTO THE GULF OF MEXICO OVER THE
LOUISIANA/TEXAS BORDER TO THE W BAY OF CAMPECHE NEAR VERACRUZ
MEXICO. THE UPPER RIDGE ASSOCIATED WITH THE AREA OF INTEREST IN
THE W CARIBBEAN WITH THE AXIS EXTENDING ACROSS CUBA NEAR HAVANA
TO OVER THE FLORIDA PENINSULA INCLUDING THE E GULF OF MEXICO.
THIS UPPER RIDGE IS PROVIDING DIFFLUNCE ALOFT TO GENERATE
SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS N OF 28N
TO INLAND OVER THE N GULF COAST BETWEEN PANAMA CITY FLORIDA TO
GRAND ISLE LOUISIANA. SEE SPECIAL FEATURES ABOVE FOR THE
ACTIVITY OVER THE SE GULF. A WEAK SURFACE RIDGE COVERS THE N
GULF ANCHORED BY A 1020 MB HIGH OVER WESTERN NORTH CAROLINA AND
WILL SHIFT N THROUGH TONIGHT AHEAD THE LOW CURRENTLY IN THE W
CARIBBEAN. THIS LOW WILL MOVE INTO CENTRAL GULF THU THEN SHIFT
NE ACROSS NE GULF FRI THROUGH SUN.

CARIBBEAN SEA...
THE PRIMARY AREA OF INTEREST IS THE SURFACE LOW/TROUGH IN THE W
CARIBBEAN. SEE SPECIAL FEATURES ABOVE. AN UPPER RIDGE COVERS THE
THE W CARIBBEAN W OF 80W ASSOCIATED WITH THE SYSTEM IN THE
SPECIAL FEATURES. THE BROAD E/W UPPER RIDGE OVER THE TROPICAL
ATLC COUPLED WITH THE UPPER RIDGE OVER THE W CARIBBEAN ARE
INDUCING AN INVERTED UPPER TROUGH OVER THE E CARIBBEAN WITH THE
AXIS EXTENDING FROM THE ABC ISLANDS TO OVER THE VIRGIN/LEEWARD
ISLANDS. CLUSTERS OF SCATTERED SHOWERS/THUNDERSTORMS ARE N OF
17N BETWEEN 66W-80W INCLUDING PORTIONS OF THE GREATER ANTILLES
FROM PUERTO RICO TO E CUBA AND JAMAICA. ISOLATED SHOWERS AND
POSSIBLE ISOLATED THUNDERSTORMS DOT THE SE CARIBBEAN S OF 16N
BETWEEN 59W-64W INCLUDING THE WINDWARD ISLANDS. THE MONSOON
TROUGH EXTENDS ALONG 10N BETWEEN COLOMBIA AND COSTA RICA
GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 45 NM
OF LINE FROM 11N80W TO NE NICARAGUA NEAR 14N83W. THE REMAINDER
OF THE CENTRAL CARIBBEAN IS UNDER REMARKABLY CLEAR SKIES THIS
EVENING. LOW OVER THE W CARIBBEAN WILL MOVE NW ACROSS THE
YUCATAN PENINSULA TONIGHT THROUGH THU. FRESH TO STRONG SE WINDS
ARE EXPECTED E OF SURFACE TROUGH WITH AN AREA OF GALE FORCE
WINDS N OF 20N BETWEEN 80W-86W. GENTLE TO MODERATE E-SE TRADES
PREVAIL ACROSS REMAINDER OF BASIN THROUGH MON.

HISPANIOLA...
CURRENTLY SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE OVER S
HAITI AND SW DOMINICAN REPUBLIC DUE TO THE UPPER RIDGE
ASSOCIATED WITH THE AREA OF INTEREST IN THE W CARIBBEAN.
NORTHERLY WINDS ALOFT AS WELL AS LOW LEVEL MOISTURE WILL
CONTINUE ACROSS THE ISLAND THROUGH THE WEEKEND. GIVEN THE
PERSISTENCE OF LOW LEVEL MOISTURE...PEAK DAYTIME HEATING...AND
INSTABILITY...AFTERNOON SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS COULD GENERATE DAILY.

ATLANTIC OCEAN...
TROPICAL STORM JERRY IS IN THE E/CENTRAL ATLC. SEE SPECIAL
FEATURES ABOVE. THE UPPER RIDGE ASSOCIATED WITH THE AREA OF
INTEREST IN THE W CARIBBEAN COVERS THE FAR W ATLC W OF 76W. AN
UPPER TROUGH EXTENDS ACROSS BERMUDA THROUGH A WEAK UPPER LOW
NEAR 27N69W TO 23N72W SUPPORTING A SURFACE TROUGH THAT
EXTENDS THROUGH 32N72W TO 29N79W. THIS UPPER TROUGH IS
AMPLIFYING AN UPPER RIDGE THAT EXTENDS S OF THE BASE OF THE
UPPER TROUGH ALONG 21N71W 26N62W TO 32N53W AND PROVIDING
DIFFLUNCE ALOFT TO GENERATE SCATTERED SHOWERS AND POSSIBLE
ISOLATED THUNDERSTORMS FROM 22N-29N BETWEEN 61-69W. A WEAK 1018
MB HIGH IS LOCATED NEAR 28N64W. A SURFACE RIDGE COVERS THE E
ATLC ANCHORED BY A 1020 MB HIGH NEAR 26N33W. W ATLC SURFACE
RIDGE HAS SHIFTED S SLIGHTLY AHEAD OF THE WEAK SURFACE TROUGH.
THIS RIDGE WILL SHIFT N TONIGHT AS THE TROUGH WEAKENS.

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

$$
PAW


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