[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 301804
TWDAT

TROPICAL WEATHER DISCUSSION
NATIONAL HURRICANE CENTER MIAMI FL
205 PM 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...SPECIAL FEATURES...
FORMER TROPICAL DEPRESSION ELEVEN INTENSIFIED TO TROPICAL STORM
JERRY NEAR 30/1500 UTC. ITS CENTER LOCATION IS NEAR 27.0N 45.7W
OR 1045 NM ESE OF BERMUDA AND IS MOVING EAST AT 6 KT. ESTIMATED
MINIMUM CENTRAL PRESSURE IS 1008 MB. MAXIMUM SUSTAINED WIND
SPEED IS 35 KT WITH GUSTS TO 45 KT. NUMEROUS MODERATE CONVECTION
AND TSTMS ARE FROM 26N-31N BETWEEN 42W-46W. SEE LATEST NHC
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC
FOR MORE DETAILS.

...TROPICAL WAVES...
TROPICAL WAVE AXIS EXTENDS FROM 15N20W TO 06N20W AND MOVES W
NEAR 20 KT. THE SOUTHERN SECTOR OF THIS WAVE IS EMBEDDED WITHIN
THE MONSOON TROUGH WHILE THE NORTHERN SECTOR IS BEING ENGULFED
BY SAHARAN DRY AIR. UPPER-LEVEL DIVERGENCE FROM A WEAK ELONGATED
HIGH IS SUPPORTING SCATTERED MODERATE CONVECTION FROM 06N-11N
BETWEEN 20W-26W.

TROPICAL WAVE AXIS EXTENDS FROM 19N33W TO 10N34W AND MOVES W
NEAR 10 KT. THE WAVE IS EMBEDDED WITHIN A VERY MOIST ENVIRONMENT
AS NOTED TOTAL PRECIPITABLE WATER IMAGERY. A ZONE OF MIDDLE TO
UPPER-LEVEL DIFFLUENCE IS SUPPORTING A CLUSTER OF MODERATE
CONVECTION AND TSTMS FROM 14N-17N BETWEEN 32W-35W.

TROPICAL WAVE AXIS EXTENDS FROM 20N66W TO 16N70W AND MOVES W-NW
NEAR 5 KT. THIS WAVE IS EMBEDDED IN A MODERATE MOIST ENVIRONMENT
AND IS MOVING SW OF THE CENTRAL ATLC SURFACE RIDGE. SCATTERED
MODERATE CONVECTION IS FROM 17N-22N BETWEEN 65W-71W. ISOLATED
SHOWERS ARE OVER THE DOMINICAN REPUBLIC AND MONA PASSAGE WHILE
TRAILING SCATTERED SHOWERS AND TSTMS ARE ACROSS PUERTO RICO AND
ADJACENT WATERS.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH AXIS EXTENDS FROM 07N19W TO 11N26W. THE
INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 11N26W TO
13N32W THEN CONTINUES WEST OF A TROPICAL WAVE FROM 09N36W TO 07N46W
06N54W. SCATTERED MODERATE CONVECTION IS FROM 07N-11N BETWEEN
25W-31W AND FROM 05N-12N BETWEEN 34W-49W.

...DISCUSSION...

GULF OF MEXICO...
A MIDDLE TO UPPER LEVEL TROUGH EXTENDING FROM PENNSYLVANIA SW TO
CENTRAL TEXAS IS SUPPORTING A FRONTAL SYSTEM THAT MOVES ACROSS
EASTERN TEXAS TO NE MEXICO NEAR 25N100W. A PRE-FRONTAL TROUGH IS
OVER THE NW GULF ALONG 29N94W TO 25N96W TO INLAND MEXICO NEAR
24N98W. SCATTERED SHOWERS ASSOCIATED WITH THE SURFACE TROUGH ARE
N OF 24N W OF 92W. OTHERWISE...THE REST OF THE GULF IS UNDER THE
INFLUENCE OF A MIDDLE TO UPPER LEVEL RIDGE WHICH ALONG WITH
SUBSIDENCE OF VERY DRY AIR CONTINUES TO SUPPORT FAIR WEATHER.
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 AFTERNOON.

CARIBBEAN SEA...
EXCEPT FOR THE CENTRAL...SOUTHERN AND NE BASIN...DRY AIR IN THE
MIDDLE AND LOWER LEVELS IS HINDERING CONVECTIVE ACTIVITY THIS
AFTERNOON. OVER THE CENTRAL CARIBBEAN AND EMBEDDED WITHIN A VERY
MOIST ENVIRONMENT...A TROUGH OF LOW PRESSURE EXTENDS FROM 18N77W
TO 11N78W. UPPER-LEVEL DIFFLUENCE FROM AN INVERTED TROUGH OVER
THE NW BASIN AND A WEAK RIDGE EASTWARD SUPPORTS SCATTERED
MODERATE CONVECTION AND TSTMS FROM 13N-19N BETWEEN 72W-
78W...INCLUDING JAMAICA AND SOUTHERN HAITI. THIS DISTURBANCE HAS
A LOW CHANCE OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48
HOURS. LOCALLY HEAVY RAINFALL IS POSSIBLE OVER PORTIONS OF HAITI
AND JAMAICA TODAY...AND WILL LIKELY SPREAD ACROSS PORTIONS OF
EASTERN CUBA AND THE CAYMAN ISLANDS LATER TODAY AND TUESDAY.
OVER THE SOUTHERN BASIN...THE MONSOON TROUGH AXIS IS ENHANCING
SCATTERED SHOWERS AND ISOLATED TSTMS SOUTH OF 12N BETWEEN 75W-
84W. A WEAK TROPICAL WAVE IS MOVING ACROSS EASTERN DOMINICAN
REPUBLIC GENERATING ISOLATED SHOWERS ACROSS HISPANIOLA AND THE
MONA PASSAGE. TRAILING SCATTERED SHOWERS AND TSTMS FROM THIS
WAVE ARE ACROSS PUERTO RICO AND WITHIN 120 NM OFF THE NORTHERN
AND SOUTHERN COASTLINES.

THE DISTURBANCE OVER THE CENTRAL GULF WILL MOVE NW THROUGH LATE
WED WHEN IT IS EXPECTED TO ENTER THE SE GULF WATERS. THE
TROPICAL WAVE WILL CONTINUE TO MOVE NW AROUND THE SURFACE RIDGE
TO MERGE WITH AN AREA OF SURFACE TROUGHINESS OVER THE SW NORTH
ATLC.

HISPANIOLA...
AN OVERALL DIFFLUENT ENVIRONMENT ALOFT ALONG WITH VERY MOIST AIR
IN THE CENTRAL CARIBBEAN SUPPORTS SCATTERED MODERATE CONVECTION
AND TSTMS FROM 13N-19N BETWEEN 72W-78W...INCLUDING JAMAICA AND
SOUTHERN HAITI. A WEAK TROPICAL WAVE IS MOVING ACROSS EASTERN
DOMINICAN REPUBLIC GENERATING ISOLATED SHOWERS ACROSS HISPANIOLA
AND THE MONA PASSAGE. ANY PROLONGED HEAVY PRECIPITATION OVER A
PARTICULAR AREA WILL RESULT IN LOCALIZED FLOODING AND A HIGHER
POTENTIAL FOR MUD SLIDES. THE TROPICAL WAVE WILL CONTINUE TO
MOVE NW AROUND THE SURFACE RIDGE TO MERGE WITH AN AREA OF
SURFACE TROUGHINESS OVER THE SW NORTH ATLC LATER TODAY.

ATLANTIC OCEAN...
ASIDE FROM TROPICAL STORM JERRY...A SURFACE TROUGH PART OF A
FRONTAL SYSTEM NORTHWARD EXTENDS ALONG 30N66W TO 25N69W TO
SUPPORT SCATTERED SHOWERS AND TSTMS N OF 24N BETWEEN 60W-68W.
THE CENTRAL ATLC IS UNDER THE INFLUENCE OF A SURFACE RIDGE
ANCHORED BY A 1019 MB HIGH CENTERED NEAR 25N54W AND A 1019 MB
HIGH OVER THE EASTERN ATLC CENTERED NEAR 25N27W. A STATIONARY
FRONT IS NE OF TROPICAL STORM JERRY EXTENDING ALONG 30N30W TO
28N35W TO 29N40W. SURFACE RIDGING IS EXPECTED TO PERSIST OVER
THE CENTRAL ATLC WITHIN THE NEXT 24 HOURS.

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

$$
NR


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