[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 171200
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT THU OCT 17 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 12N41W TO 4N44W MOVING W NEAR 20 KT.
WAVE IS EMBEDDED WITHIN A BROAD AREA OF DEEP MOISTURE AS
DEPICTED ON THE TOTAL PRECIPITABLE WATER IMAGERY. THIS WAVE IS
BENEATH AN UPPER RIDGE WITH NO ASSOCIATED DEEP CONVECTION.

TROPICAL WAVE EXTENDS FROM 17N48W TO 9N56W MOVING W NEAR 10 KT.
WAVE IS EMBEDDED WITHIN A BROAD AREA OF DEEP MOISTURE AS
DEPICTED ON THE TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 75/90 NM EITHER SIDE
OF THE WAVE BETWEEN 11N-14N AND FROM 8N-12N BETWEEN 58W-62W.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL
ATLC NEAR 13N17W AND CONTINUES ALONG 9N17W TO 7N20W WHERE THE
ITCZ BEGINS AND CONTINUES ALONG 6N28W TO E OF THE EASTERN MOST
TROPICAL WAVE NEAR 9N39W THEN RESUMES W OF THE WAVE NEAR 9N46W
TO SOUTH AMERICA NEAR 8N61W. CLUSTERS OF SCATTERED MODERATE/
ISOLATED STRONG CONVECTION ARE INLAND AND WITHIN 120 NM ALONG
THE COAST OF AFRICA BETWEEN 6N-11N...WITHIN 90 NM EITHER SIDE OF
THE ITCZ BETWEEN 21W-30W...FROM 3N-9N BETWEEN 32N-39N...AND FROM
8N-11N BETWEEN 40W-51W.

...DISCUSSION...

GULF OF MEXICO...
A BROAD UPPER TROUGH IS OVER THE CENTRAL PLAIN STATES MOVING
OVER THE UPPER MISSISSIPPI VALLEY SUPPORTING A COLD FRONT THAT
ENTERS THE NW GULF OVER SW LOUISIANA NEAR VERMILION BAY TO OVER
NE MEXICO JUST S OF THE TEXAS/MEXICO BORDER. SCATTERED SHOWERS
AND POSSIBLE ISOLATED THUNDERSTORMS ARE WITHIN 60 NM SE OF THE
FRONT WITH ISOLATED SHOWERS W OF THE FRONT TO INLAND OVER
LOUISIANA AND TEXAS. A BROAD UPPER RIDGE DOMINATES THE GULF
WATERS ANCHORED N OF THE YUCATAN PENINSULA NEAR 22N88W. A WEAK
SURFACE RIDGE COVERS THE REMAINDER OF THE GULF ANCHORED BY A
1016 MB HIGH OFF THE FLORIDA COAST NEAR 29N87W. THE SOUTHERLY
FLOW W OF THE HIGH AND E OF THE FRONT ARE GENERATING ISOLATED
SHOWERS WITHIN 60 NM OF LINE FROM 27N91W TO INLAND OVER THE N
GULF COAST NEAR BILOXI MISSISSIPPI. THIS IS LEAVING THE
REMAINDER OF THE GULF UNDER MOSTLY CLEAR SKIES THIS MORNING.
COLD FRONT WILL EXTEND FROM MISSISSIPPI TO NE MEXICO LATE TODAY
THEN BECOME STATIONARY FROM THE FLORIDA PANHANDLE TO EXTREME S
TEXAS FRI. REINFORCING SURGE ON SAT WILL ALLOW FRONT TO MOVE S
AGAIN BEFORE STALLING AGAIN LATE SUN AND MON.

CARIBBEAN SEA...
THE UPPER RIDGE OVER THE GULF OF MEXICO COVERS THE NW CARIBBEAN
NW OF LINE FROM CUBA NEAR 20N76W TO HONDURAS NEAR 16N84W WITH
DRY STABLE AIR ALOFT AS SHOWN ON SATELLITE WATER VAPOR IMAGERY.
A SECOND UPPER RIDGE COVERS THE E CARIBBEAN E OF A LINE FROM
PUERTO RICO TO COLOMBIA NEAR SANTA MARTA. THE UPPER TROUGH
EXTENDS FROM THE W ATLC BETWEEN THESE UPPER RIDGES ACROSS THE
CENTRAL CARIBBEAN BETWEEN HISPANIOLA TO COSTA RICA. SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS ARE N OF 18N BETWEEN 72W-77W
INCLUDING THE WINDWARD PASSAGE AND S OF 14N TO INLAND OVER SOUTH
AMERICA BETWEEN 66W-76W. THE MONSOON TROUGH EXTENDS FROM
COLOMBIA NEAR 10N75W ALONG 11N79W ACROSS PANAMA AND COSTA RICA
NEAR THE BORDER WITH SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S
OF 11N W OF 76W. ISOLATED SHOWERS ARE OVER THE NW CARIBBEAN
WITHIN 90 NM OF LINE FROM 18N80W TO OVER THE YUCATAN/CENTRAL
AMERICA AND THE GULF OF HONDURAS NEAR 16N88W AND OVER THE
E/CENTRAL CARIBBEAN FROM 14N-17N BETWEEN 65W-72W. WEAK PRESSURE
GRADIENT AND BELOW NORMAL TRADE WINDS WILL PREVAIL THROUGH MON.

HISPANIOLA...
CURRENTLY SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE OVER
PORTIONS OF THE ISLAND THIS MORNING. THE UPPER TROUGH GENERATING
THIS ACTIVITY WILL SHIFT E BY FRI. THIS WILL GIVE THE ISLAND A
MORE NORTHERLY FLOW ALOFT RESULTING IN A REDUCE CHANCE OF
SHOWERS/THUNDERSTORMS. HOWEVER...WITH DAYTIME HEATING AFTERNOON
SHOWERS/ISOLATED THUNDERSTORMS REMAIN A POSSIBILITY.

ATLANTIC OCEAN...
THE UPPER RIDGE OVER THE GULF OF MEXICO EXTENDS OVER THE W ATLC
W OF 74W. AN UPPER TROUGH COVERS THE REMAINDER OF THE W ATLC
EXTENDING FROM AN UPPER LOW NEAR 29N66W ACROSS HISPANIOLA INTO
THE CENTRAL CARIBBEAN SUPPORTING A SURFACE TROUGH THAT EXTENDS
ACROSS BERMUDA ALONG 29N67W 26N71W THROUGH THE BAHAMA ISLANDS TO
NEAR 21N74W. LARGE CLUSTERS OF SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS ARE WITHIN 150/180 NM E OF THE SURFACE TROUGH S OF
31N. A LINGERING DISSIPATING STATIONARY FRONT IS IN THE CENTRAL
ATLC EXTENDING THROUGH 32N30W ALONG 28N39W TO 27N48W. ISOLATED
SHOWERS ARE POSSIBLE WITHIN 60 NM EITHER SIDE OF THE FRONT. A
WEAK SURFACE RIDGE COVERS THE E ATLC ANCHORED BY A 1020 MB HIGH
OVER THE MADEIRA ISLANDS. THE W ATLC SURFACE TROUGH WILL PERSIST
THROUGH FRI. A COLD FRONT WILL ENTER THE FAR NW PORTION LATE SUN
AND EXTEND FROM 31N75W TO NE FLORIDA BY LATE MON.

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

$$
PAW


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