[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 030553
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT THU OCT 03 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...SPECIAL FEATURES...
TROPICAL DEPRESSION JERRY IS CENTERED NEAR 29.7N 42.0W AT
03/0300 UTC OR ABOUT 895 NM WSW OF THE AZORES MOVING NE AT 6 KT.
ESTIMATED MINIMUM CENTRAL PRESSURE IS 1010 MB. MAXIMUM SUSTAINED
WIND SPEED IS 30 KT WITH GUSTS TO 40 KT. ISOLATED MODERATE
CONVECTION IS FROM 24N-31N BETWEEN 38W-45W. SEE LATEST NHC
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC
FOR MORE DETAILS.

A SURFACE TROUGH IS ANALYZED ACROSS THE SOUTHEAST GULF OF MEXICO
AND THE WESTERN CARIBBEAN SEA FROM COASTAL HONDURAS NEAR 16N86W
INTO A 1006 MB LOW CENTERED NEAR 20N86W TO 26N85W. WATER VAPOR
IMAGERY INDICATES THIS TROPICAL DISTURBANCE FALLS BENEATH AN
UPPER LEVEL ANTICYCLONIC CIRCULATION CENTERED NEAR 21N82W
PRIMARILY ON THE WESTERN PERIPHERY IN THE AREA OF MAXIMUM UPPER
LEVEL DIFFLUENCE. LOW-LEVEL MOISTURE CONVERGENCE IN THE VICINITY
OF THE LOW AND TROUGH AXIS ALONG WITH THE FAVORABLE UPPER LEVEL
DIFFLUENT ENVIRONMENT IS GENERATING SCATTERED MODERATE AND
ISOLATED STRONG CONVECTION FROM 19N-23N BETWEEN 84W-88W. THIS
DISTURBANCE IS EXPECTED TO MOVE NORTH-NORTHWESTWARD THROUGH THE
YUCATAN CHANNEL OVERNIGHT INTO THE CENTRAL GULF THURSDAY.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 07N42W TO 15N42W MOVING W AT 15 KT.
THE WAVE REMAINS EMBEDDED WITHIN WEAK SURFACE TO 700 MB
TROUGHING WITH A 700 MB RELATIVE VORTICITY MAXIMUM NOTED ALONG
THE WAVE AXIS NEAR 12N. ISOLATED MODERATE CONVECTION IS FROM 09N-
17N BETWEEN 39W-45W.

TROPICAL WAVE EXTENDS FROM 10N52W TO 21N50W MOVING W-NW AT 10-15
KT. THE WAVE CONTINUES TO STRETCH NORTHWARD AS THE SURFACE TO
700 MB TROUGHING BROADENS BETWEEN 48W-58W. WITH SOUTHWESTERLY
WIND SHEAR ALOFT TO THE NW OF THE WAVE AXIS...CONVECTION REMAINS
LIMITED AT THIS TIME WITH ONLY ISOLATED MODERATE CONVECTION
OCCURRING 07N-13N BETWEEN 48W-55W.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 12N16W TO
07N25W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM
07N25W TO 07N41W. ASIDE FROM CONVECTION ASSOCIATED WITH THE
TROPICAL WAVES ACROSS THE CENTRAL TROPICAL ATLC...ISOLATED
MODERATE CONVECTION IS FROM 07N-12N BETWEEN 23W-33W.

...DISCUSSION...

GULF OF MEXICO...
SOUTH-SOUTHWESTERLY UPPER LEVEL FLOW DOMINATES OVER THE GULF
THIS EVENING BETWEEN A MIDDLE TO UPPER LEVEL TROUGH AXIS
EXTENDING FROM OVER LOUISIANA NEAR 31N93W TO A BASE NEAR 21N97W
AND AN UPPER LEVEL ANTICYCLONIC CIRCULATION CENTERED OVER THE NW
CARIBBEAN SEA NEAR 21N82W. WATER VAPOR IMAGERY INDICATES THAT
MOST OF THIS FLOW ALOFT REMAINS RELATIVELY DRY W OF
90W...LEAVING CONDITIONS ACROSS THE WESTERN GULF RELATIVELY
QUIET THIS EVENING WITHIN E-SE SURFACE WINDS IN THE RANGE OF 10
TO 15 KT. ACROSS THE EASTERN GULF...MOISTURE INCREASES DUE TO A
1006 MB SURFACE LOW CENTERED ACROSS THE YUCATAN CHANNEL NEAR
20N86W AND THE ASSOCIATED TROUGHING EXTENDING NORTHWARD INTO THE
SE GULF TO 26N85W. GIVEN A FAVORABLE UPPER LEVEL DIFFLUENT
ENVIRONMENT ALREADY IN PLACE...SCATTERED SHOWERS AND ISOLATED
TSTMS ARE OCCURRING PRIMARILY S OF 28N E OF 90W. LOOKING
AHEAD...THE SURFACE LOW IS FORECAST TO MOVE NORTH-NORTHWEST
DURING THE NEXT 24 TO 48 HOURS INTO THE CENTRAL AND SE GULF
THURSDAY AND BEGIN IMPACTING THE NORTHERN GULF WATERS LATE
THURSDAY INTO FRIDAY.

CARIBBEAN SEA...
AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED OVER THE
WESTERN CARIBBEAN NEAR 21N82W AND IS PROVIDING FOR AN OVERALL
DIFFLUENT ATMOSPHERE N OF 16N W OF 76W. AT THE SURFACE BENEATH
THIS UPPER LEVEL FEATURE...A SURFACE TROUGH EXTENDS ALONG 86W
WITH A 1006 MB LOW CENTERED ALONG THE AXIS NEAR 20N. LOW-LEVEL
MOISTURE CONVERGENCE IS MAXIMIZED IN THE VICINITY OF THE LOW
GENERATING SCATTERED SHOWERS AND STRONG TSTMS FROM 19N-23N
BETWEEN 83W-87W. FARTHER SOUTH...WHILE THE UPPER LEVEL DIFFLUENT
ENVIRONMENT REMAINS IN PLACE...LOW-LEVEL MOISTURE CONVERGENCE
BECOMES SOMEWHAT WEAKER...HOWEVER INTERACTION WITH LAND AND
DIFFERENTIAL HEATING CONTINUES TO GENERATE SCATTERED SHOWERS AND
ISOLATED TSTMS FROM 08N-17N BETWEEN 82W-90W...INCLUDING INLAND
PORTIONS OF COSTA RICA...NICARAGUA...HONDURAS...AND EL SALVADOR.
THE REMAINDER OF THE CENTRAL AND EASTERN CARIBBEAN FALLS UNDER
THE INFLUENCE OF DRY AND OVERALL STABLE NORTHEASTERLY FLOW ALOFT
WITH ONLY WIDELY SCATTERED LOW-TOPPED SHOWERS OCCURRING WITHIN E-
SE TRADES E OF 75W.

HISPANIOLA...
CURRENTLY NORTHERLY DRY AND STABLE UPPER LEVEL FLOW IS NOTED ON
WATER VAPOR IMAGERY OVER HISPANIOLA THIS EVENING. THIS IS
PROVIDING FOR AN OVERALL TRANQUIL OVERNIGHT PERIOD...HOWEVER LOW-
LEVEL MOISTURE AND ISOLATED LOW-TOPPED SHOWERS ARE EXPECTED TO
CONTINUE MOVING IN ACROSS THE ISLAND FROM THE EAST. E-SE TRADES
ARE EXPECTED TO CONTINUE DURING THE NEXT 24 TO 36 HOURS WITH
THIS LOW-LEVEL MOISTURE PROVIDING FOR A PASSING SHOWER HERE AND
THERE THROUGH THE EARLY AFTERNOON HOURS. GIVEN THE PERSISTENCE
OF LOW-LEVEL MOISTURE...PEAK DAYTIME HEATING...AND
INSTABILITY...SCATTERED SHOWERS AND TSTMS CANNOT BE RULED OUT IN
THE FORECAST FOR THURSDAY AFTERNOON AND EARLY EVENING.

ATLANTIC OCEAN...
A MIDDLE TO UPPER LEVEL TROUGH AXIS EXTENDS FROM THE NORTHWEST
NORTH ATLC NEAR 42N52W SW TO 32N62W INTO A MIDDLE TO UPPER LEVEL
LOW NEAR 26N68W. WHILE PRIMARILY WEAK SURFACE RIDGING DOMINATES
N OF 20N W OF 50W...THE MIDDLE TO UPPER LEVEL TROUGH IS
GENERATING CLOUD COVER WITH WIDELY SCATTERED SHOWERS AND
ISOLATED TSTMS OVER THE SW NORTH ATLC WITHIN 180 NM EITHER SIDE
OF A LINE FROM 22N70W TO 34N53W. OTHERWISE...A SHALLOW SURFACE
TROUGH IS ANALYZED TO THE WEST OF THIS UPPER LEVEL FEATURE FROM
25N71W TO 32N78W. WITH A LACK OF UPPER LEVEL SUPPORT...ONLY A
FEW ISOLATED SHOWERS ARE OCCURRING WITHIN 300 NM NE OF THE
TROUGH AXIS. TO THE SOUTHWEST OF THIS AREA...THE ADVECTION OF
TROPICAL MOISTURE FROM THE WESTERN CARIBBEAN SEA CONTINUES TO
IMPACT THE FLORIDA STRAITS AND FLORIDA PENINSULA THIS EVENING
WITH WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS OCCURRING S OF
27N W OF 75W. OTHERWISE...ACROSS THE CENTRAL ATLC...TROPICAL
DEPRESSION JERRY CONTINUES TO SPIN IN THE VICINITY OF 29N42W.
SURROUNDING THE DEPRESSION IS RELATIVELY WEAK RIDGING ANCHORED
BY A 1019 MB HIGH CENTERED NEAR 24N32W AND A 1019 MB HIGH
CENTERED NEAR 35N37W.

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

$$
HUFFMAN


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