[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 300550
TWDAT

TROPICAL WEATHER DISCUSSION
NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT MON SEP 30 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 ELEVEN IS CENTERED NEAR 27.0N 47.0W AT
30/0300 UTC OR ABOUT 980 NM ESE OF BERMUDA AND ABOUT 1035 NM NE
OF THE NORTHERN LEEWARD ISLANDS MOVING ENE AT 8 KT. ESTIMATED
MINIMUM CENTRAL PRESSURE IS 1010 MB. MAXIMUM SUSTAINED WIND
SPEED IS 30 KT WITH GUSTS TO 40 KT. SCATTERED MODERATE
CONVECTION IS FROM 26N-30N BETWEEN 44W-47W. SEE LATEST NHC
FORECAST/ ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC
FOR MORE DETAILS.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 08N33W TO 20N30W MOVING W AT 15 KT.
THE WAVE IS EMBEDDED WITHIN A VERY MOIST ENVIRONMENT AS NOTED
TOTAL PRECIPITABLE WATER IMAGERY FROM 08N-23N  BETWEEN 25W-35W
AND CONTINUES TO COINCIDE WITH SURFACE TO 700 MB TROUGHING AND A
RELATIVE VORTICITY MAXIMUM ALONG THE WAVE AXIS NEAR 14N.
ISOLATED MODERATE CONVECTION IS FROM 07N-17N BETWEEN 27W-35W.

TROPICAL WAVE EXTENDS FROM 11N70W TO 20N66W MOVING W-NW AT 20
KT. THE WAVE IS LOCATED SOUTH OF SUBTROPICAL TROUGHING AS A
SURFACE LOW PRESSURE SYSTEM DEVELOPS ACROSS THE SW NORTH ATLC
THAT IS FORECAST TO MOVE NORTHWARD OVER THE NEXT 24 TO 36 HOURS.
AS A RESULT...ENERGY FROM THE WAVE IS FRACTURING NORTHWARD INTO
THIS LOW-LEVEL TROUGHING WHILE ANY REMAINING ENERGY IS EXPECTED
TO BECOME DIFFUSE ACROSS THE CENTRAL CARIBBEAN SEA. WIDELY
SCATTERED MODERATE CONVECTION IS FROM 15N-23N BETWEEN 66W-75W.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 12N16W TO
08N20W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM
08N20W TO 12N26W THEN FROM 08N35W TO 06N54W. ISOLATED MODERATE
CONVECTION IS FROM 05N-11N BETWEEN 17W-25W. SCATTERED MODERATE
CONVECTION IS FROM 07N-09N BETWEEN 34W-46W. A SURFACE TROUGH IS
ANALYZED NEAR THE WESTERN EXTENT OF THE ITCZ AXIS FROM 06N57W TO
11N56W AND IS PROVIDING FOCUS FOR ISOLATED MODERATE CONVECTION
FROM 03N-13N BETWEEN 50W-61W.

...DISCUSSION...

GULF OF MEXICO...
WATER VAPOR IMAGERY INDICATES MUCH OF THE GULF BASIN IS UNDER
THE INFLUENCE OF A MIDDLE TO UPPER LEVEL RIDGE ANCHORED OVER THE
WESTERN GULF NEAR 25N95W. OVERALL THIS IS PROVIDING MUCH OF THE
BASIN WITH STABLE CONDITIONS THIS EVENING...HOWEVER AN UPPER
LEVEL TROUGH AXIS NOTED EXTENDING FROM OVER THE OHIO RIVER
VALLEY SW TO OVER OKLAHOMA AND THE TEXAS PANHANDLE CONTINUES TO
MOVE SOUTHEASTWARD AND EVENTUALLY WILL INTERACT WITH A
STATIONARY FRONT ANALYZED FROM THE TEXAS GULF COAST NEAR 29N96W
TO NEAR BROWNSVILLE AND INLAND OVER NE MEXICO. WIDELY SCATTERED
SHOWERS AND ISOLATED TSTMS ARE OCCURRING N OF 24N W OF 96W WITH
ONLY ISOLATED LOW-TOPPED SHOWERS OCCURRING ELSEWHERE AT THIS
TIME DUE TO THE OTHERWISE STABLE CONDITIONS ALOFT. WEAK SURFACE
RIDGING IS EXPECTED TO REMAIN IN PLACE EXTENDING FROM THE SE
CONUS TO THE SW GULF WATERS PROVIDING GENERALLY 10 TO 15 KT E-SE
WINDS THROUGH WEDNESDAY.

CARIBBEAN SEA...
A MIDDLE TO UPPER LEVEL TROUGH AXIS EXTENDS FROM OVER THE SW
NORTH ATLC NEAR 23N74W SW TO 20N78W TO A BASE NEAR 16N85W. WEST
OF THE TROUGH AXIS...WATER VAPOR IMAGERY INDICATES VERY DRY AIR
ALOFT AND OVERALL STABLE CONDITIONS THIS EVENING FOR THE NW
CARIBBEAN WITH ONLY A FEW ISOLATED SHOWERS NOTED ACROSS EASTERN
CUBA AND THE ADJACENT COASTAL WATERS N OF 20N BETWEEN 77W-83W.
BENEATH THE UPPER LEVEL TROUGHING AND AREAS TO THE EAST...MOIST
SOUTHWESTERLY FLOW ALOFT CONTINUES TO ADVECT MOISTURE AND
CLOUDINESS FROM THE CENTRAL CARIBBEAN N-NE INTO A DEVELOPING LOW
PRESSURE SYSTEM IN THE VICINITY OF BERMUDA IN THE SW NORTH ATLC.
THIS MOISTURE...ALONG WITH A SURFACE TROUGH ALONG 79W AND A
WEAKENING TROPICAL WAVE ALONG 68W IS PROVIDING FOCUS FOR A BROAD
AREA OF WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS FROM 10N-14N
BETWEEN 70W-85W...AND FROM 14N-20N BETWEEN 66W-79W. CONVECTION
OCCURRING ACROSS THE SW CARIBBEAN IS LIKELY ENHANCED DUE TO THE
CLOSE PROXIMITY OF THE MONSOON TROUGH ANALYZED FROM NORTHERN
COLOMBIA WESTWARD TO COSTA RICA THEN NORTHWESTWARD TO
SOUTHWESTERN HONDURAS. FINALLY...WATER VAPOR IMAGERY SHOWS AN
UPPER LEVEL LOW CENTERED OVER THE SE CARIBBEAN NEAR 10N63W THAT
CONTINUES TO DRIFT WEST AND PROVIDE TRINIDAD AND TOBAGO...ALONG
WITH THE SOUTHERN WINDWARD ISLANDS WITH INCREASED MOISTURE AND
CLOUDINESS. ISOLATED SHOWER ACTIVITY IS EXPECTED TO INCREASE
OVERNIGHT INTO MONDAY GENERALLY SOUTH OF 13N E OF 64W.

HISPANIOLA...
CURRENTLY MOIST SOUTHWESTERLY FLOW ALOFT EAST OF AN UPPER LEVEL
TROUGH AXIS EXTENDING FROM OVER THE SE BAHAMAS SOUTHWEST TO OVER
16N84W IS PROVIDING THE ISLAND WITH PLENTY OF MOISTURE AND
CLOUDINESS OVERHEAD THIS EVENING. WITH AN OVERALL UPPER LEVEL
DIFFLUENT ENVIRONMENT IN PLACE...SCATTERED SHOWERS AND ISOLATED
TSTMS ARE ONGOING AND EXPECTED TO PERSIST THROUGH THE OVERNIGHT
HOURS INTO MONDAY. THE APPROACH OF A TROPICAL WAVE ALONG 68W IS
EXPECTED TO INVIGORATE AFTERNOON AND EVENING CONVECTION MONDAY.
AS THIS AREA OF CLOUDINESS AND PRECIPITATION TRAINS FROM THE S-
SW OVER HISPANIOLA AND INTO THE SW NORTH ATLC...ANY PROLONGED
HEAVY PRECIPITATION OVER A PARTICULAR AREA WILL RESULT IN
LOCALIZED FLOODING AND A HIGHER POTENTIAL FOR MUD SLIDES.

ATLANTIC OCEAN...
A MIDDLE TO UPPER LEVEL LOW IS CENTERED OFF THE COAST OF THE
CAROLINAS NEAR 34N72W THAT EXTENDS A TROUGH AXIS SOUTHWARD ALONG
73W TO OVER THE SE BAHAMAS THEN SW TO A BASE OVER THE NW
CARIBBEAN SEA. THE TROUGHING SUPPORTS A 1009 MB LOW CENTERED
NORTH OF BERMUDA NEAR 34N65W WITH A DISSIPATING STATIONARY FRONT
EXTENDING INTO THE DISCUSSION AREA NEAR 32N62W TO 23N72W. A
SURFACE TROUGH REMAINS TO THE WEST ANALYZED FROM 31N67W TO
23N74W. WITH LARGE-SCALE MOISTURE TRANSPORT ONGOING AND LOW-
LEVEL MOISTURE CONVERGENCE IN THE VICINITY OF THE BOUNDARIES...
SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING FROM 19N-32N
BETWEEN 58W-74W. THE REMAINDER OF THE SW NORTH ATLC WEST OF THE
SURFACE TROUGH REMAINS UNDER MOSTLY FAIR SKIES AND ONLY A FEW
ISOLATED SHOWERS. FARTHER EAST...ASIDE FROM TROPICAL DEPRESSION
ELEVEN...THE CENTRAL ATLC IS UNDER THE INFLUENCE OF A SURFACE
RIDGE ANCHORED BY A 1019 MB HIGH CENTERED NEAR 26N55W AND
ANOTHER SURFACE RIDGE ACROSS THE EASTERN ATLC ANCHORED BY A 1020
MB HIGH CENTERED NEAR 25N24W. A COLD FRONT CONTINUES TO PASS
MAINLY TO THE NORTH OF 30N BETWEEN 30W-38W...WITH ONLY A FEW
ISOLATED SHOWERS POSSIBLE N OF 28N BETWEEN 28W-42W.

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

$$
HUFFMAN


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