[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 260533
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT THU SEP 26 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 19N41W TO 10N39W MOVING W 10-15 KT.
WAVE IS EMBEDDED WITHIN A SURGE OF DEEP MOISTURE AS DEPICTED ON
THE TOTAL PRECIPITABLE WATER IMAGERY. THE WAVE THE W IS BENEATH
AN UPPER LOW ENHANCING THE ACTIVITY WHICH IS SPREADING E TO THIS
WAVE. SCATTERED MODERATE/STRONG CONVECTION IS ASSOCIATED WITH
THE ITCZ RATHER THAN THIS WAVE. CLUSTERS OF SCATTERED MODERATE
TO ISOLATED STRONG CONVECTION ARE FROM 12N-18N BETWEEN 36W-44W.

TROPICAL WAVE EXTENDS FROM 18N52W TO 10N48W MOVING W NEAR 15 KT.
WAVE IS EMBEDDED WITHIN A SURGE OF DEEP MOISTURE AS DEPICTED ON
THE TOTAL PRECIPITABLE WATER IMAGERY. THIS IS WAVE IS BENEATH AN
UPPER LOW ENHANCING SCATTERED MODERATE WITH EMBEDDED CLUSTERS OF
ISOLATED STRONG CONVECTION FROM 9N-17N BETWEEN 44W-52W.

TROPICAL WAVE JUST E OF THE LEEWARD ISLANDS EXTENDS FROM 22N59W
TO 14N60W MOVING W-NW 10-15 KT. WAVE IS EMBEDDED WITHIN DRY AIR
AS DEPICTED ON THE TOTAL PRECIPITABLE WATER IMAGERY. ISOLATED
SHOWERS ARE POSSIBLE WITHIN 45 NM OF THE WAVE.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL
ATLC NEAR 14N17W AND CONTINUES ALONG 11N17W 7N19W TO 7N27W WHERE
THE ITCZ BEGINS AND CONTINUES ALONG 7N31W 10N40W TO 9N45W.
SCATTERED MODERATE/STRONG CONVECTION IS WITHIN 120/150 NM N OF
THE ITCZ BETWEEN 36W-42W. CLUSTERS OF SCATTERED MODERATE/
ISOLATED STRONG CONVECTION ARE FROM 4N-8N BETWEEN 21W-23W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER TROUGH EXTENDS FROM AN UPPER LOW OVER WEST VIRGINIA
ACROSS THE CAROLINAS TO NE FLORIDA INTO THE GULF TO 26N90W. A
LOW LEVEL SURFACE TROUGH IS BENEATH THIS UPPER TROUGH EXTENDING
FROM A 1007 MB LOW OVER TALLAHASSEE FLORIDA ALONG 28N87W THROUGH
A 1008 MB LOW NEAR 28N89W TO 25N93W. ISOLATED SHOWERS ARE
POSSIBLE WITHIN 60 NM OF THE 1008 MB LOW. AN UPPER TROUGH IN THE
W ATLC IS SUPPORTING A STATIONARY FRONT THAT CROSSES N FLORIDA
THROUGH JACKSONVILLE AND THE 1007 MB LOW OVER TALLAHASSEE TO THE
FLORIDA/ALABAMA BORDER WHERE IT BECOMES A COLD FRONT ALONG
29N90W TO 27N93W. AN UPPER RIDGE EXTENDS OVER S MEXICO TO THE
YUCATAN PENINSULA PROVIDING DIFFLUNCE ALOFT TO GENERATE
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS INLAND OVER S MEXICO
AND WITHIN 60 NM ALONG THE COAST IN THE BAY OF CAMPECHE BETWEEN
MERIDA AND TAMPICO. THE 1008 MB SURFACE LOW WILL MOVE NE AND
DISSIPATE LATER TONIGHT. THE WEAK COLD FRONT WILL MOVE SE ACROSS
THE E GULF THU AND FRI. A SURFACE RIDGE WILL BUILD ACROSS THE
GULF THU THROUGH MON.

CARIBBEAN SEA...
AN UPPER RIDGE ANCHORED IN THE W ATLC COVERS THE FAR NW
CARIBBEAN N OF LINE FROM CENTRAL CUBA TO THE NE TIP OF THE
YUCATAN CHANNEL. AN INVERTED UPPER TROUGH AXIS EXTENDS FROM
ACROSS COSTA RICA TO OVER HISPANIOLA ENHANCING THE ACTIVITY
ASSOCIATED WITH THE MONSOON TROUGH AND GENERATING SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS WITHIN 45 NM RADIUS OF THE E TIP
OF THE DOMINICAN REPUBLIC INCLUDING PORTIONS OF THE MONA
PASSAGE...OVER THE GULF OF GONAVE AND PORTIONS OF HAITI FROM 17N-
20N BETWEEN 71W-74W...OVER SE CUBA FROM 20N-21N BETWEEN 76W-
78W...AND W OF JAMAICA FROM 17N-19N BETWEEN 78W-81W. THE MONSOON
TROUGH EXTENDS FROM COLOMBIA NEAR 10N74W ALONG 10N80W TO ACROSS
COSTA RICA NEAR 9N84W GENERATING SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS S OF 14N W OF 75W TO INLAND OVER PANAMA TO
NICARAGUA. ISOLATED SHOWERS ARE POSSIBLE OVER THE E CARIBBEAN
FROM 13N-7N E OF 67W USHERED IN ON THE EASTERLY TRADE WINDS.
EASTERLY TRADE WINDS WILL PREVAIL THROUGH MON. A BROAD LOW
PRESSURE IS EXPECTED TO DEVELOP OVER THE SW CARIBBEAN SAT AND
CONTINUING THROUGH MON.

HISPANIOLA...
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE OVER SW HAITI AND
THE GULF OF GONAVE WHILE THE SKIES REMAIN MOSTLY CLEAR ACROSS
THE REMAINDER OF THE ISLAND TONIGHT. EASTERLY FLOW ALOFT AND AT
THE SURFACE WILL CONTINUE THROUGH FRI. THE UPPER RIDGE
RESPONSIBLE FOR THE E FLOW ALOFT WILL THEN RETREAT E AS AN UPPER
RIDGE ANCHORED TO THE S CHANGES THE UPPER FLOW TO WESTERLY. THE
REMNANTS OF A WEAK TROPICAL WAVE WILL MOVE ACROSS THE ISLAND
LATE FRI BEFORE COMPLETELY DISSIPATING SAT. THIS WILL POSSIBLY
INCREASE OR INTENSIFY AFTERNOON SHOWERS/THUNDERSTORMS.

ATLANTIC OCEAN...
THE UPPER RIDGE IS ANCHORED OVER THE W ATLC NEAR 25N75W
EXTENDING A RIDGE AXIS SW TO OVER W CUBA AND NE TO BEYOND
32N62W. THIS UPPER RIDGE IS PROVIDING DIFFLUNCE ALOFT TO
GENERATE SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS N
OF 28N BETWEEN 66W-78W. AN UPPER TROUGH N OF 30N OVER THE
CENTRAL ATLC IS SUPPORTING A COLD FRONT THAT ENTERS THE REGION
NEAR 32N58W ALONG 29N63W TO 29N67W WHERE IT BECOMES WARM FRONT
ALONG 31N71W TO A WEAKENING 1007 MB LOW NEAR 30N73W THEN
CONTINUES AS STATIONARY TO A DEVELOPING 1007 MB LOW NEAR 30N79W
THEN ACROSS FLORIDA NEAR JACKSONVILLE. SCATTERED SHOWERS/
ISOLATED THUNDERSTORMS ARE WITHIN 120 NM OF LINE FROM 27N55W TO
33N49W. THE REMAINDER OF THE ATLC IS DOMINATED BY A SURFACE
RIDGE ANCHORED BY A 1020 MB HIGH NEAR 25N38W. THE EASTERN 1007
MB LOW WILL MOVE MAINLY EAST PASSING TO THE S OF BERMUDA ON THU
WHILE DRAGGING A WEAK COLD FRONT ACROSS AREA N OF 27N. THE
WESTERN DEVELOPING 1007 MB LOW WILL MOVE TO NEAR 28N75W BY FRI
WITH THE ASSOCIATED COLD FRONT EXTENDING ACROSS THE NW BAHAMAS
AND THE STRAITS OF FLORIDA. THIS SECOND FRONT WILL STALL ACROSS
THE CENTRAL BAHAMAS ON FRI NIGHT. A REINFORCING NORTHERLY SURGE
WILL MOVE INTO THE W ATLC LATE FRI MERGING WITH THE INITIAL
FRONT ACROSS THE CENTRAL BAHAMAS ON SUN THEN DISSIPATING THROUGH
MON NIGHT.

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

$$
PAW


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