[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 031204
TWDAT

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

...SPECIAL FEATURES...
TROPICAL DEPRESSION JERRY IS CENTERED NEAR 30.2N 41.4W AT
03/0900 UTC OR ABOUT 855 NM WSW OF THE AZORES MOVING NE AT 8 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 28N-31N BETWEEN 36W-43W. 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
NEAR 26N86W INTO A 1006 MB LOW CENTERED NEAR 21N87W. WATER VAPOR
IMAGERY INDICATES THIS TROPICAL DISTURBANCE FALLS BENEATH AN
UPPER LEVEL ANTICYCLONIC CIRCULATION CENTERED NEAR 21N84W
PRIMARILY ON THE WESTERN PERIPHERY IN THE AREA OF MAXIMUM UPPER
LEVEL DIFFLUENCE. LOW-LEVEL MOISTURE CONVERGENCE IN THE VICINITY
OF THE LOW ALONG WITH THE FAVORABLE UPPER LEVEL DIFFLUENT
ENVIRONMENT IS GENERATING SCATTERED MODERATE AND ISOLATED STRONG
CONVECTION FROM 19N-24N BETWEEN 84W-87W. THIS DISTURBANCE IS
EXPECTED TO MOVE NORTH-NORTHWESTWARD INTO THE CENTRAL GULF
THURSDAY. DATA FROM AN AIR FORCE RESERVE HURRICANE HUNTER
AIRCRAFT INDICATE THAT THE AREA OF LOW PRESSURE LOCATED OVER THE
SOUTHEASTERN GULF OF MEXICO HAS BECOME A TROPICAL STORM AND IS
PRODUCING WINDS OF UP TO 60 MPH IN THE EXTREME SOUTHEASTERN GULF
OF MEXICO. A SPECIAL ADVISORY WILL BE ISSUED WITHIN THE NEXT
HOUR...AND HURRICANE AND TROPICAL STORM WATCHES WILL BE ISSUED
FOR PARTS OF THE NORTHERN GULF OF MEXICO COAST. THIS SYSTEM HAS
A HIGH CHANCE OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48
HOURS...AND A HIGH CHANCE OF BECOMING A TROPICAL CYCLONE DURING
THE NEXT 5 DAYS AS IT MOVES NORTH-NORTHWESTWARD. HEAVY RAINS
COULD AFFECT PORTIONS OF CUBA AND THE YUCATAN PENINSULA DURING
THE NEXT DAY OR TWO. AN AIR FORCE RESERVE HURRICANE HUNTER
AIRCRAFT IS CURRENTLY INVESTIGATING THE SYSTEM. ADDITIONAL
INFORMATION ON THIS SYSTEM CAN BE FOUND IN HIGH SEAS FORECASTS
ISSUED BY THE NATIONAL WEATHER SERVICE.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 11N44W TO 19N42W 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 15N. ISOLATED MODERATE CONVECTION IS FROM 11N-
17N BETWEEN 39W-48W.

TROPICAL WAVE EXTENDS FROM 13N54W TO 22N54W MOVING W-NW AT 10-15
KT. THE WAVE CONTINUES TO STRETCH NORTHWARD AS THE SURFACE TO
700 MB TROUGHING BROADENS BETWEEN 49W-60W. WITH SOUTHWESTERLY
WIND SHEAR ALOFT TO THE NW OF THE WAVE AXIS...CONVECTION REMAINS
LIMITED AT THIS TIME WITH ONLY ISOLATED MODERATE CONVECTION
OCCURRING 08N-14N BETWEEN 49W-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 07N34W TO 11N42W. ASIDE FROM CONVECTION ASSOCIATED
WITH THE TROPICAL WAVES ACROSS THE CENTRAL TROPICAL ATLC...
ISOLATED MODERATE CONVECTION IS FROM 06N-10N BETWEEN 30W-35W.

...DISCUSSION...

GULF OF MEXICO...
SOUTH-SOUTHWESTERLY UPPER LEVEL FLOW DOMINATES OVER THE GULF
THIS MORNING BETWEEN A MIDDLE TO UPPER LEVEL TROUGH AXIS
EXTENDING FROM OVER LOUISIANA NEAR 30N91W TO A BASE NEAR 20N98W
AND AN UPPER LEVEL ANTICYCLONIC CIRCULATION CENTERED OVER THE NW
CARIBBEAN SEA NEAR 21N84W. 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
MORNING WITHIN LIGHT ANTICYCLONIC WINDS IN THE RANGE OF 5 TO 15
KT. ACROSS THE EASTERN GULF...MOISTURE INCREASES DUE TO A 1006
MB SURFACE LOW CENTERED NEAR THE NORTHEASTERN TIP OF THE YUCATAN
PENINSULA NEAR 21N87W AND THE ASSOCIATED TROUGHING EXTENDING
NORTHWARD INTO THE SE GULF TO 26N86W. GIVEN A FAVORABLE UPPER
LEVEL DIFFLUENT ENVIRONMENT ALREADY IN PLACE...SCATTERED SHOWERS
AND ISOLATED TSTMS ARE OCCURRING PRIMARILY S OF 28N E OF
90W...WITH PLENTY OF MIDDLE TO UPPER LEVEL CLOUDINESS SPREADING
NORTHWARD ACROSS THE REMAINDER OF THE EASTERN GULF AND FLORIDA
PENINSULA. LOOKING AHEAD...THE SURFACE LOW IS FORECAST TO MOVE
NORTH-NORTHWEST DURING THE NEXT 24 TO 48 HOURS INTO THE CENTRAL
GULF TODAY 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 21N84W AND IS PROVIDING FOR AN OVERALL
DIFFLUENT ATMOSPHERE W OF 82W. AT THE SURFACE BENEATH THIS UPPER
LEVEL FEATURE...A 1006 MB SURFACE LOW IS CENTERED 21N87W. LOW-
LEVEL MOISTURE CONVERGENCE IS MAXIMIZED IN THE VICINITY OF THE
LOW GENERATING WIDESPREAD SHOWERS AND SCATTERED STRONG TSTMS
FROM 19N-24N BETWEEN 84W-88W...INCLUDING THE YUCATAN CHANNEL.
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 W OF A LINE FROM 18N85W TO 09N76W. MOST OF THIS ACTIVITY
IS FOUND ACROSS CENTRAL AMERICA AND WITHIN CLOSE PROXIMITY TO
THE MONSOON TROUGH AXIS ANALYZED ALONG 09N/10N. THE REMAINDER OF
THE CENTRAL CARIBBEAN FALLS UNDER THE INFLUENCE OF DRY AND
OVERALL STABLE NORTHEASTERLY FLOW ALOFT W OF AN UPPER LEVEL
TROUGH AXIS EXTENDING FROM 18N66W TO 10N72W. ALONG AND TO THE
EAST OF THIS UPPER LEVEL TROUGH AXIS...LOW-LEVEL MOISTURE
CONVERGENCE AND MARGINAL DYNAMICS ARE GENERATING WIDELY
SCATTERED SHOWERS AND ISOLATED TSTMS E OF 72W.

HISPANIOLA...
CURRENTLY NORTHERLY DRY AND STABLE UPPER LEVEL FLOW IS NOTED ON
WATER VAPOR IMAGERY OVER HISPANIOLA THIS MORNING. THIS IS
PROVIDING FOR AN OVERALL TRANQUIL MORNING...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 39N51W SW TO 32N60W INTO A MIDDLE TO UPPER LEVEL
LOW NEAR 25N67W. WHILE PRIMARILY WEAK SURFACE RIDGING DOMINATES
N OF 20N W OF 55W...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 32N54W TO 22N70W. OTHERWISE...A SHALLOW SURFACE
TROUGH IS ANALYZED TO THE WEST OF THIS UPPER LEVEL FEATURE FROM
24N73W TO 27N72W TO 29N72W. WITH A LACK OF UPPER LEVEL
SUPPORT...ONLY A FEW ISOLATED SHOWERS ARE OCCURRING WITHIN 210
NM E OF THE TROUGH AXIS. OTHERWISE...ACROSS THE CENTRAL ATLC...A
COLD FRONT EXTENDS INTO THE DISCUSSION AREA NEAR 32N50W SW TO
27N55W WITH ISOLATED SHOWERS OCCURRING WITHIN 120 NM EITHER SIDE
OF THE FRONT. THE FRONT IS LOCATED WEST OF A WEAKNESS WITHIN
TROPICAL RIDGING WHERE TROPICAL DEPRESSION JERRY CONTINUES TO
SPIN IN THE VICINITY OF 30N42W. SURFACE TROUGHING EXTENDS
SOUTHWEST OF THE SYSTEM WITH A SURFACE TROUGH ANALYZED FROM
21N49W TO 25N46W AND LIKELY ENERGY THAT FRACTURED OFF OF THE
TROPICAL WAVE ALONG 54W. TO THE EAST OF THE DEPRESSION COVERING
THE REMAINDER OF THE EASTERN ATLC...RELATIVELY WEAK RIDGING IS
ANCHORED BY A PAIR OF 1018 MB HIGHS CENTERED NEAR 27NN33W AND
36N36W.

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

$$
HUFFMAN


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