[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 240003
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT WED SEP 23 2015

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 IDA IS CENTERED NEAR 19.9N 46.6W AT 23/2100 UTC
OR ABOUT 945 NM E OF THE NORTHERN LEEWARD ISLANDS MOVING E AT 4
KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1005 MB. MAXIMUM
SUSTAINED WIND SPEED IS 35 KT WITH GUSTS TO 45 KT. SCATTERED
MODERATE TO NUMEROUS STRONG CONVECTION COVERS THE AREA FROM 18N-
21N BETWEEN 42W-47W. PLEASE SEE THE LATEST NHC FORECAST/ADVISORY
UNDER AWIPS/WMO HEADERS MIATCMAT5/WTNT25 KNHC FOR MORE DETAILS.

...TROPICAL WAVES...

TROPICAL WAVE EXTENDS FROM 16N23W TO 9N25W MOVING W NEAR 5 KT OF
THE PAST 24 HOURS. SSMI TPW INDICATES THE WAVE IS ALONG THE
LEADING EDGE OF A SURGE OF MODERATE/DEEP MOISTURE. SCATTERED
SHOWERS ARE WITHIN 90 NM W OF THE WAVE N OF 12N AND WITHIN
90/120 NM E OF THE WAVE N OF 14N.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL
ATLC NEAR 14N17W ALONG 9N23W TO 8N31W WHERE THE ITCZ BEGINS AND
CONTINUES TO 8N37W. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS INLAND AND WITHIN 60 NM ALONG THE COAST OF W
AFRICA BETWEEN 13N-17N. SCATTERED MODERATE CONVECTION IS FROM 8N-
10N BETWEEN 17W-20W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER TROUGH IS WEDGED BETWEEN A PAIR OF BROAD UPPER
RIDGES...ONE ANCHORED OVER N/CENTRAL MEXICO AND ONE EXTENDING
FROM THE CARIBBEAN OVER THE W ATLC. THE UPPER TROUGH EXTENDS
FROM THE E CONUS INTO THE GULF OF MEXICO OVER PANAMA CITY
FLORIDA TO THE NW YUCATAN PENINSULA AND OVER THE E BAY OF
CAMPECHE SUPPORTING A SURFACE TROUGH THAT EXTENDS FROM 28N86W
TO 24N90W. SECOND WEAKER SURFACE TROUGH EXTENDS FROM 24N87W
THROUGH THE YUCATAN CHANNEL TO 19N86W. CLUSTERS OF SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS ARE S OF 27N E OF 87W TO OVER S
FLORIDA...CUBA...AND THROUGH THE STRAITS OF FLORIDA. ISOLATED
SHOWERS/THUNDERSTORMS DOT THE REMAINDER OF THE E ATLC E OF 90W.
A DIURNAL SURFACE TROUGH IS IN THE SW ALONG ALONG 94W S OF 21N
WITH SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 60 NM W OF
THE TROUGH AXIS. STRONG SUBSIDENCE AND DRY STABLE AIR WITH CLEAR
SKIES COVER THE REMAINDER OF THE GULF W OF 90W. WEAK SURFACE
RIDGE WILL BUILD SW OVER THE N GULF THROUGH FRI.

CARIBBEAN SEA...
AN UPPER RIDGE EXTENDS FROM CENTRAL PANAMA ACROSS E CUBA INTO
THE W ATLC COVERING THE W CARIBBEAN W OF 72W. A LARGE UPPER LOW
CENTERED N OF PUERTO RICO/VIRGIN ISLANDS COVERS THE REMAINDER OF
THE E CARIBBEAN. A SURFACE TROUGH EXTENDS FROM THE GULF OF MEXICO
NEAR 24N87W THROUGH THE YUCATAN CHANNEL TO 19N86W. A SECOND
SURFACE TROUGH IS OVER THE SW CARIBBEAN EXTENDING FROM 15N83W TO
10N82W. SCATTERED TO NUMEROUS SHOWERS/ISOLATED THUNDERSTORMS ARE
S OF 16N W OF 78W TO INLAND OVER CENTRAL AMERICA. AFTERNOON
SHOWERS/THUNDERSTORMS HAVE DEVELOPED INLAND OVER PUERTO RICO...
HISPANIOLA...AND CUBA THIS EVENING. THE ACTIVITY THAT IS OVER
PUERTO RICO AND HISPANIOLA IS MOVING SE INTO THE INTO THE
COASTAL WATERS INCLUDING THE MONA PASSAGE AND THE VIRGIN
ISLANDS. ISOLATED SHOWERS/THUNDERSTORMS DOT THE NW CARIBBEAN N
OF 18N W OF 80W. THIS IS LEAVING THE REMAINDER OF THE CARIBBEAN
E OF 72W WITH CLEAR SKIES THIS EVENING. WEAK SURFACE RIDGE OVER
THE SW ATLC WILL SUPPORT GENTLE TO MODERATE TRADE WINDS ACROSS
MOST OF THE CARIBBEAN THROUGH FRI EXCEPT FOR PULSES OF FRESH TO
STRONG WINDS OFF COLOMBIA AND W VENEZUELA MAINLY AT NIGHT.

...HISPANIOLA...
NUMEROUS SHOWERS/SCATTERED THUNDERSTORMS ARE ACROSS THE ISLAND
THIS EVENING. DAYTIME HEATING COUPLED WITH OROGRAPHIC LIFTING
WILL CONTINUE TO GENERATE AFTERNOON SHOWERS/THUNDERSTORMS ACROSS
THE ISLAND THU AND FRI.

ATLANTIC OCEAN...
A REMNANT STATIONARY FRONT EXTENDS THROUGH 32N79W TO A WEAK 1013
MB LOW NEAR 29N79W THEN CONTINUES W TO OVER FLORIDA NEAR
MELBOURNE. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE N OF 31N
W OF THE FRONT AND WITHIN 60 NM OF THE LOW CENTER. AN UPPER
RIDGE EXTENDS FROM THE CARIBBEAN ACROSS CUBA NEAR 21N77W TO
32N74W. A SURFACE TROUGH IS OVER THE N BAHAMA ISLANDS EXTENDING
FROM 28N77W TO THE N COAST OF CUBA NEAR 22N79W. SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS ARE S OF 28N W OF 75W. AFTERNOON
SHOWERS/THUNDERSTORMS HAVE DEVELOPED INLAND OVER CUBA ARE MOVING
N WITHIN 75 NM ALONG THE COAST OF CUBA BETWEEN 75W-83W. A WEAK
1015 MB HIGH IS OVER THE W/CENTRAL ATLC NEAR 30N65W. A LARGE
UPPER LOW IS CENTERED N OF PUERTO RICO/VIRGIN ISLANDS NEAR
25N66W GENERATING CLUSTERS OF SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS FROM 21N-29N BETWEEN 60W-72W. AN UPPER RIDGE OVER
THE E ATLC S OF 30N E OF 40W IS PROVIDING DIFFLUNCE ALOFT TO
GENERATE SCATTERED TO NUMEROUS SHOWERS AND POSSIBLE ISOLATED
THUNDERSTORMS FROM 20N-30N BETWEEN 32W-40W. A BROAD SURFACE
RIDGE COVERS THE E ATLC N OF 30N E OF 50W ANCHORED BY A 1023 MB
HIGH N OF THE AZORES. W ATLC FRONT WILL STALL AND TRANSITION TO
A SURFACE TROUGH THU. A WEAK SURFACE RIDGE WILL PERSIST E OF THE
BAHAMAS THROUGH FRI.

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

$$
PAW
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