[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 301046
TWDAT

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

...SPECIAL FEATURES...
TROPICAL DEPRESSION ELEVEN IS CENTERED NEAR 26.9N 46.7W AT
30/0900 UTC OR ABOUT 1000 NM ESE OF BERMUDA AND ABOUT 1195 NM
WSW OF THE AZORES MOVING E AT 4 KT. ESTIMATED MINIMUM CENTRAL
PRESSURE IS 1010 MB. MAXIMUM SUSTAINED WIND SPEED IS 30 KT WITH
GUSTS TO 45 KT. SCATTERED MODERATE CONVECTION IS FROM 26N-31N
BETWEEN 43W-47W. SEE LATEST NHC FORECAST/ADVISORY UNDER
AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC FOR MORE DETAILS.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 06N17W TO 14N17W MOVING W AT 15 KT.
THE WAVE COINCIDES WITH A MAXIMUM IN TOTAL PRECIPITABLE WATER
IMAGERY THAT HAS EMERGED OFF THE COAST OF AFRICA IN THE VICINITY
OF 09N18W. THIS ALONG WITH AN INTERESTING BROAD CYCLONIC CLOUD
PRESENTATION EAST OF THE WAVE AXIS IS GENERATING WIDELY
SCATTERED MODERATE CONVECTION FROM 07N-12N BETWEEN 18W-26W.

TROPICAL WAVE EXTENDS FROM 10N34W TO 21N32W MOVING W AT 15 KT.
THE WAVE IS EMBEDDED WITHIN A VERY MOIST ENVIRONMENT AS NOTED
TOTAL PRECIPITABLE WATER IMAGERY FROM 07N-20N BETWEEN 27W-36W
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 12N-17N BETWEEN 32W-35W.

TROPICAL WAVE EXTENDS FROM 15N70W TO 20N67W MOVING W-NW AT 15
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. SCATTERED
MODERATE CONVECTION IS FROM 17N-22N BETWEEN 65W-71W.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM 08N18W TO 09N24W. THE
INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 09N24W TO
12N33W THEN FROM 09N35W TO 04N51W. WIDELY SCATTERED MODERATE
CONVECTION IS FROM 06N-10N BETWEEN 34W-46W.

...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
CENTRAL GULF NEAR 24N90W. OVERALL THIS IS PROVIDING MUCH OF THE
BASIN WITH STABLE CONDITIONS THIS MORNING...HOWEVER AN UPPER
LEVEL TROUGH AXIS IS NOTED EXTENDING FROM OVER THE OHIO RIVER
VALLEY SW TO OVER ARKANSAS AND NORTH TEXAS THAT 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 23N W OF 93W 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 22N73W SW TO 20N78W TO A BASE NEAR 17N84W. WEST
OF THE TROUGH AXIS...WATER VAPOR IMAGERY INDICATES VERY DRY AIR
ALOFT AND OVERALL STABLE CONDITIONS THIS MORNING FOR THE NW
CARIBBEAN. 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 NORTH OF BERMUDA IN THE SW NORTH
ATLC. THIS MOISTURE...ALONG WITH A SURFACE TROUGH ALONG 79W AND
A WEAKENING TROPICAL WAVE ALONG 69W IS PROVIDING FOCUS FOR A
BROAD AREA OF WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS FROM
08N-18N BETWEEN 73W-80W...AND FROM 16N-24N BETWEEN 65W-73W.
CONVECTION OCCURRING ACROSS THE SW CARIBBEAN IS LIKELY ENHANCED
DUE TO A COMPLEX AREA OF SURFACE LOW PRESSURE ANCHORED BY A 1009
MB LOW CENTERED NEAR 14N79W AND A 1010 MB LOW CENTERED TO ITS
SOUTHWEST NEAR 12N81W. 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 PERSIST
MONDAY GENERALLY SOUTH OF 14N E OF 63W.

HISPANIOLA...
CURRENTLY MOIST SOUTHWESTERLY FLOW ALOFT EAST OF AN UPPER LEVEL
TROUGH AXIS EXTENDING FROM OVER THE SE BAHAMAS SOUTHWEST TO OVER
17N84W IS PROVIDING THE ISLAND WITH PLENTY OF MOISTURE AND
CLOUDINESS OVERHEAD THIS MORNING. WITH AN OVERALL UPPER LEVEL
DIFFLUENT ENVIRONMENT IN PLACE...SCATTERED SHOWERS AND ISOLATED
TSTMS ARE OCCURRING AND EXPECTED TO PERSIST THROUGH THE DAY ON
MONDAY. THE APPROACH OF A TROPICAL WAVE ALONG 69W IS EXPECTED TO
INVIGORATE AFTERNOON AND EVENING CONVECTION. 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 34N71W THAT EXTENDS A TROUGH AXIS SOUTHWARD ALONG
70W TO 24N THEN SW TO A BASE OVER THE NW CARIBBEAN SEA. THE
TROUGHING SUPPORTS A 1008 MB LOW CENTERED NORTH OF BERMUDA NEAR
36N67W WITH A DISSIPATING STATIONARY FRONT EXTENDING TO 31N67W
THE CONTINUING SW AS A SURFACE TROUGH TO 26N71W. WITH LARGE-
SCALE MOISTURE TRANSPORT ONGOING AND LOW-LEVEL MOISTURE
CONVERGENCE IN THE VICINITY OF THE BOUNDARY...SCATTERED SHOWERS
AND ISOLATED TSTMS ARE OCCURRING WITHIN 210 NM EITHER SIDE OF A
LINE FROM 32N63W TO 20N70W. 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 26N54W
AND ANOTHER SURFACE RIDGE ACROSS THE EASTERN ATLC ANCHORED BY A
1018 MB HIGH CENTERED NEAR 24N27W. A COLD FRONT CONTINUES TO
PASS MAINLY TO THE NORTH OF 28N BETWEEN 26W-44W...WITH A FEW
ISOLATED SHOWERS AND TSTMS OCCURRING WITHIN 90 NM EITHER SIDE OF
THE FRONT...AND FROM 29N-32N BETWEEN 42W-48W.

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

$$
HUFFMAN


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