[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 242341
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT MON SEP 24 2012

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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...SPECIAL FEATURES...

TROPICAL STORM NADINE IS CENTERED NEAR 31.7N 28.6W AT 24/2100
UTC OR ABOUT 385 NM SSW OF THE AZORES MOVING W AT 6 KT.
ESTIMATED MINIMUM CENTRAL PRESSURE IS 993 MB. MAXIMUM SUSTAINED
WIND SPEED IS 45 KT WITH GUSTS TO 55 KT. WIDELY SCATTERED
MODERATE CONVECTION IS FROM 31N-36N BETWEEN 26W-32W. SEE LATEST
NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24
KNHC FOR MORE DETAILS.

...TROPICAL WAVES...

TROPICAL WAVE EXTENDS FROM 12N59W TO 19N56W MOVING W AT 15 KT.
THE WAVE REMAINS ON THE WESTERN PERIPHERY OF VERY BROAD LOW-
LEVEL TROUGHING ACROSS THE TROPICAL ATLC S OF 20N BETWEEN
45W-60W. TOTAL PRECIPITABLE WATER IMAGERY INDICATES ELEVATED
VALUES EAST OF THE LESSER ANTILLES FROM 10N-18N BETWEEN
53W-60W...WHICH STRETCH WESTWARD INTO THE SOUTHEASTERN CARIBBEAN
SEA S OF 15N E OF 69W. WHILE NO SIGNIFICANT DEEP CONVECTION IS
IN THE VICINITY OF THE AXIS OF THE WAVE...SCATTERED MODERATE
CONVECTION IS OCCURRING ACROSS THE EASTERN CARIBBEAN FROM
10N-17N BETWEEN 61W-68W.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 15N17W TO
09N31W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM
09N31W TO 10N44W. WIDELY SCATTERED MODERATE CONVECTION IS FROM
09N-15N BETWEEN 13W-18W. ISOLATED MODERATE CONVECTION IS FROM
06N-15N BETWEEN 22W-38W.

...DISCUSSION...

GULF OF MEXICO...
WATER VAPOR IMAGERY INDICATES AN UPPER LEVEL SHORTWAVE TROUGH IS
OVER THE WESTERN GULF WITH AXIS EXTENDING FROM 30N89W TO A BASE
NEAR 22N96W. EAST OF THIS UPPER LEVEL TROUGH AXIS...UPPER LEVEL
DIFFLUENCE IS MAXIMIZED OVER MUCH OF THE CENTRAL AND EASTERN
GULF...INCLUDING THE FLORIDA PENINSULA DUE TO MOIST
SOUTHWESTERLY FLOW BETWEEN THE TROUGHING AND AN UPPER LEVEL
RIDGE AXIS EXTENDING FROM OVER CENTRAL AMERICA NEAR 17N90W EAST-
NORTHEASTWARD TO BEYOND 30N64W. THE UPPER LEVEL SHORTWAVE TROUGH
IS A PORTION OF A LARGER LONGWAVE TROUGH LOCATED OVER THE
EASTERN CONUS THAT SUPPORTS A COLD FRONT ANALYZED ACROSS THE SW
NORTH ATLC TO THE SOUTHERN FLORIDA PENINSULA AND WESTWARD INTO
THE GULF OF MEXICO AS A STATIONARY FRONT FROM 26N82W TO 24N90W.
ONLY ISOLATED SHOWERS AND TSTMS ARE ASSOCIATED WITH THE FRONT S
OF 25N BETWEEN 84W-97W. MUCH OF THE MOISTURE NORTH OF THE
FRONTAL BOUNDARY REMAINS AS BROKEN TO OVERCAST MIDDLE TO HIGH
LEVEL CLOUDINESS. A SURFACE TROUGH IS ALSO ANALYZED ACROSS THE
SW GULF FROM 23N95W TO 17N93W AND IS ALSO LIKELY A FOCUS FOR THE
SCATTERED SHOWERS AND TSTMS OCCURRING OVER THE SW GULF S OF 23N
W OF 90W. THE FRONT IS FORECAST TO BECOME MORE AND MORE DIFFUSE
OVER THE NEXT 24 TO 36 HOURS AS SURFACE HIGH PRESSURE REMAINS
OVER THE NORTHERN GULF WATERS AND COASTAL PLAINS THROUGH LATE
TUESDAY. MOSTLY EASTERLY FLOW IS EXPECTED TO PERSIST ON THE
SOUTHERN PERIPHERY OF THE HIGH IN THE RANGE OF 10 TO 20 KT. AS
THE HIGH SHIFTS EASTWARD BY EARLY WEDNESDAY...E TO SE WINDS ARE
FORECAST TO RE-ESTABLISH ACROSS THE WESTERN GULF.

CARIBBEAN SEA...
AN UPPER LEVEL RIDGE AXIS EXTENDS FROM OVER PORTIONS OF CENTRAL
AMERICA NEAR 17N90W EAST-NORTHEASTWARD TO BEYOND 30N64W. WITH A
STATIONARY FRONT DRAPED ACROSS THE SE GULF OF MEXICO AND
DIFFLUENCE MAXIMIZED IN ASSOCIATION WITH THE UPPER LEVEL
RIDGING...SCATTERED SHOWERS AND TSTMS ARE OCCURRING OVER MUCH OF
THE NW CARIBBEAN NW OF A LINE FROM THE WINDWARD PASSAGE NEAR
20N74W TO 12N84W. THE MOST INTENSE ACTIVITY THIS EVENING IS
LOCATED OVER CUBA...THE YUCATAN CHANNEL...AND PORTIONS OF THE
YUCATAN PENINSULA...INCLUDING NORTHERN GUATEMALA. FARTHER SE...
THE MONSOON TROUGH AXIS EXTENDS INTO THE SW CARIBBEAN ALONG 10N
AND IS PROVIDING FOCUS FOR SCATTERED SHOWERS AND ISOLATED TSTMS
S OF 12N BETWEEN 76W-85W...INCLUDING PORTIONS OF PANAMA...COSTA
RICA...AND SOUTHERN NICARAGUA. THE CENTRAL CARIBBEAN REMAINS
UNDER MOSTLY FAIR CONDITIONS AND CLEAR SKIES BETWEEN 70W-76W. AN
UPPER LEVEL LOW CENTERED OVER PUERTO RICO NEAR 18N66W EXTENDS
TROUGHING TO ANOTHER UPPER LEVEL LOW NEAR 13N74W AND NE FLOW
ALOFT IS LIKELY PROVIDING A SUBSIDENT ENVIRONMENT FOR THE
CENTRAL CARIBBEAN. FINALLY...EAST OF THE UPPER LEVEL
TROUGHING...MOIST SOUTHWESTERLY FLOW DOMINATES EAST OF A PUERTO
RICO TO ARUBA LINE WITH SCATTERED SHOWERS AND TSTMS OCCURRING
EAST OF THAT LINE...INCLUDING PUERTO RICO AND THE LESSER
ANTILLES THIS EVENING. THE APPROACH OF A TROPICAL WAVE ALONG 58W
WILL LIKELY CONTINUE TO ENHANCE THIS CONVECTIVE ACTIVITY THROUGH
THE OVERNIGHT HOURS INTO TUESDAY.

ATLANTIC OCEAN...
AN UPPER LEVEL TROUGH HAS EMERGED OFF THE EASTERN SEABOARD OF
THE CONUS AND SUPPORTS A COLD FRONT ANALYZED INTO THE DISCUSSION
AREA ALONG 32N70W TO 27N76W TO THE SOUTHERN FLORIDA PENINSULA
NEAR 26N80W. LOW-LEVEL CONVERGENCE ALONG THE FRONT IN CONCERT
WITH MIDDLE TO UPPER LEVEL DIFFLUENCE EAST OF THE TROUGH AXIS IS
GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS OVER MUCH OF THE
SW NORTH ATLC WEST OF A LINE FROM BERMUDA NEAR 32N65W TO 24N69W
TO 22N77W. THE COLD FRONT IS FORECAST TO CONTINUE LIFTING NORTH-
NORTHEASTWARD OVER THE NEXT 24 TO 36 HOURS WITH A STATIONARY
FRONT FORECAST TO LINGER ACROSS THE NW BAHAMAS AND SOUTHERN
FLORIDA PENINSULA THROUGH TUESDAY AS THE UPPER LEVEL SUPPORT
LIFTS NORTHWARD. FARTHER EAST...THE CENTRAL ATLC IS UNDER THE
INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1030 MB HIGH CENTERED
NEAR 42N41W. THE SURFACE RIDGE AXIS EXTENDS SOUTHWEST FROM THE
HIGH TO 26N65W. THE ONLY AREA OF ACTIVE WEATHER WITHIN REACH OF
THE SURFACE RIDGE IS AN UPPER LEVEL LOW CENTERED NEAR 27N59W
WHICH IS GENERATING WIDELY SCATTERED SHOWERS FROM 25N-32N
BETWEEN 55W-59W. THE REMAINDER OF THE EASTERN ATLC IS UNDER THE
INFLUENCE OF TROPICAL STORM NADINE N OF 27N BETWEEN 22W-35W...
AND A 1016 MB HIGH CENTERED SOUTH OF NADINE NEAR 20N31W.

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

$$
HUFFMAN




This weather bulletin was brought to you by:
www.nashvilleweather.net