[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 192353
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT WED SEP 19 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 37.2N 31.9W AT 20/0000
UTC OR ABOUT 135 NM SSW OF FLORES IN THE AZORES NEAR STATIONARY.
ESTIMATED MINIMUM CENTRAL PRESSURE IS 990 MB. MAXIMUM SUSTAINED
WIND SPEED IS 45 KT WITH GUSTS TO 55 KT. SEE LATEST NHC
INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT4/
WTNT34 AND THE FULL FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS
MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS. AREA IS VOID OF ANY DEEP
CONVECTION. SCATTERED SHOWERS AND POSSIBLE ISOLATED
THUNDERSTORMS COVER THE AREA FROM 34N-43N BETWEEN 27W-37W.

A LARGE UPPER LOW IS IN THE CENTRAL ATLC NEAR 30N52W SUPPORTING
A WEAK 1013 MB SURFACE LOW NEAR 31N52W WITH A SURFACE TROUGH
EXTENDING SW ALONG 28N54W TO 26N58W. THE CIRCULATION OF THE LOW
IS GRADUALLY BECOMING BETTER DEFINED AND THE ASSOCIATED SHOWER
ACTIVITY IS SLOWLY INCREASING IN ORGANIZATION. THIS SYSTEM HAS A
MEDIUM CHANCE OF BECOMING A SUBTROPICAL CYCLONE DURING THE NEXT
48 HOURS AS IT MOVES W TO WNW AT ABOUT 9 KT. CLUSTERS OF
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE FROM 23N-28N
BETWEEN 46W-52W AND N OF 29N BETWEEN 44W-55W.

...TROPICAL WAVES...

TROPICAL WAVE EXTENDS FROM 21N23W THROUGH THE CAPE VERDE ISLANDS
TO 12N22W MOVING W 15-20 KT. WAVE IS EMBEDDED WITHIN A SURGE OF
DEEP MOISTURE AS DEPICTED ON TOTAL PRECIPITABLE WATER IMAGERY.
SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS ARE OVER
THE CAPE VERDE ISLANDS.

TROPICAL WAVE IN THE E TROPICAL ATLC EXTENDS FROM 19N46W TO
9N52W MOVING NW NEAR 15 KT. WAVE IS EMBEDDED WITHIN AN ISOLATED
SURGE OF DEEP MOISTURE AS DEPICTED ON TOTAL PRECIPITABLE WATER
IMAGERY. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 60
NM SE AND WITHIN 150 NM NW OF THE WAVE AXIS ENHANCED BY AN UPPER
RIDGE TO THE E.

TROPICAL WAVE IN THE CARIBBEAN EXTENDS 21N72W THROUGH THE
WINDWARD PASSAGE TO 12N76W MOVING W NEAR 20 KT. WAVE IS EMBEDDED
WITHIN A BROAD AREA OF DEEP MOISTURE THAT COVERS THE ENTIRE
CARIBBEAN AS DEPICTED ON TOTAL PRECIPITABLE WATER IMAGERY.
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE FROM 15N-20N
BETWEEN 74W-79W.


...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS W AFRICA INTO THE E TROPICAL
ATLC NEAR 18N16W CONTINUING S OF THE TROPICAL WAVE NEAR 10N22W
TO 5N36W WHERE THE ITCZ CONTINUES ALONG 4N45W INTO SOUTH AMERICA
NEAR 4N52W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS
FROM 6N-7N BETWEEN 41W-44W. CLUSTERS OF SCATTERED MODERATE
CONVECTION ARE FROM 5N-9N BETWEEN 13W-25W.

...DISCUSSION...

GULF OF MEXICO...
BROAD UPPER TROUGH COVERS THE E CONUS INTO THE GULF N OF 22N
SUPPORTING A COLD FRONT THAT AT 19/2100 UTC EXTENDS FROM THE W
ATLC ACROSS FLORIDA INTO THE GULF NEAR TAMPA TO 26N85W WHERE IT
CONTINUES AS A STATIONARY FRONT ALONG 22N92W THEN S TO 20N92W.
CLUSTERS OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE N OF
THE FRONT AND 23N E OF 93W AND S OF THE FRONT TO OVER S
FLORIDA...CUBA...AND THE YUCATAN PENINSULA. AN UPPER RIDGE
COVERS THE S GULF WITH THE RIDGE AXIS OVER S MEXICO ENHANCING
ISOLATED SHOWERS/THUNDERSTORMS WITHIN 45 NM ALONG THE COAST OF S
MEXICO IN THE BAY OF CAMPECHE. THIS IS LEAVING THE REMAINDER OF
THE GULF UNDER MOSTLY FAIR WEATHER THIS EVENING. THE STATIONARY
FRONT WILL WEAKEN THROUGH THU NIGHT THEN DISSIPATE FRI. HIGH
PRESSURE WILL THEN BUILD S FRI THROUGH SUN.

CARIBBEAN SEA...
A LARGE UPPER RIDGE IS ANCHORED OVER THE BAHAMA ISLANDS COVERING
THE CENTRAL CARIBBEAN BETWEEN 63W-80W. DIFFLUENCE ALOFT IS
GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 15N TO
OVER THE GREATER ANTILLES BETWEEN PUERTO RICO AND HAITI. AN
UPPER RIDGE IS ANCHORED IN THE E PACIFIC REGION EXTENDING AN
AXIS ACROSS S MEXICO INTO THE CARIBBEAN ACROSS BELIZE TO 17N83W
PROVIDING DIFFLUENCE ALOFT TO GENERATE SCATTERED SHOWERS/
ISOLATED THUNDERSTORMS N OF 21N TO OVER CUBA W OF 79W WITH
CLUSTERS OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM
13N-16N BETWEEN 81W-83W. THE UPPER RIDGES ARE INDUCING AN
INVERTED UPPER TROUGH FROM 79W-83W BETWEEN PANAMA AND CUBA.
TROPICAL WAVE WILL MOVE THROUGH THE W CARIBBEAN AND REACH THE
YUCATAN PENINSULA EARLY SAT. THE E TROPICAL ATLC WAVE WILL MOVE
INTO THE E CARIBBEAN FRI AND OVER THE CENTRAL CARIBBEAN SAT AND
SUN.

ATLANTIC OCEAN...
THE UPPER TROUGH THAT COVERS THE E CONUS AND GULF OF MEXICO
EXTENDS OVER THE NW ATLC SUPPORTING A COLD FRONT THAT AT 19/2100
UTC ENTERS THE DISCUSSION AREA NEAR 32N77W EXTENDING OVER THE
FLORIDA PENINSULA NEAR DAYTONA BEACH TO TAMPA BEFORE ENTERING
THE GULF OF MEXICO. AN UPPER RIDGE IS ANCHORED OVER THE BAHAMA
ISLANDS NEAR 23N73W EXTENDING S OVER THE CARIBBEAN AND N TO
BEYOND 32N62W. TROPICAL STORM NADINE IN THE NE ATLC WITH A WEAK
1017 MB HIGH OVER THE E ATLC NEAR 24N36W. A COLD FRONT WILL
WEAKENING AS IT STALLS THROUGH EARLY FRI AND GRADUALLY
DISSIPATE. HIGH PRESSURE WILL THEN BUILD S FRI THROUGH SUN.

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

$$
PAW





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