[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 021202
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT FRI AUG 02 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.

...SPECIAL FEATURES...
A SURFACE TROUGH...REMNANTS OF DORIAN...EXTENDS FROM 28N78W
BETWEEN THE BAHAMA ISLANDS AND S FLORIDA TO THE COAST OF CUBA
NEAR 23N80W. SCATTERED SHOWERS AND POSSIBLE ISOLATED
THUNDERSTORMS ARE WITHIN 150 NM E OF THE SURFACE TROUGH. GRADUAL
DEVELOPMENT OF THIS SYSTEM IS POSSIBLE BEFORE UPPER-LEVEL WINDS
BECOME UNFAVORABLE OVER THE WEEKEND. CLOUDINESS...SHOWERS...AND
GUSTY WINDS ARE POSSIBLE TO PORTIONS OF THE NW BAHAMAS AND THE
COASTAL WATERS OF SE FLORIDA TODAY AND SATURDAY AS THE SYSTEM
MOVES NW AND N. AFTER THAT THE SYSTEM IS EXPECTED TO MOVE TOWARD
THE N-NE AND BECOME ASSOCIATED WITH A FRONTAL TROUGH CURRENTLY
OVER THE SE CONUS. THIS SYSTEM HAS A MEDIUM CHANCE OF BECOMING A
TROPICAL CYCLONE DURING THE NEXT 48 HOURS.

...TROPICAL WAVES...
TROPICAL WAVE NEAR THE CAPE VERDE ISLANDS EXTENDS FROM 22N23W
THROUGH A WEAK 1010 MB LOW NEAR 18N23W TO 13N23W MOVING W NEAR 5
KT. WAVE IS EMBEDDED WITHIN AN AREA OF MODERATE MOISTURE AS
DEPICTED ON THE TOTAL PRECIPITABLE WATER IMAGERY WITH A WELL
DEFINED BUT BROAD MID LEVEL CIRCULATION. HOWEVER...THE WAVE IS
ALSO EMBEDDED WITH A DENSE LAYER OF DRY SAHARAN DUST THAT COVERS
THE TROPICAL ATLC LIMITING ANY SHOWER ACTIVITY.

TROPICAL WAVE OVER THE S GULF OF MEXICO ALONG 89W/90W S OF 25N
TO OVER THE YUCATAN PENINSULA TO NW GUATEMALA MOVING W 10-15 KT.
WAVE IS EMBEDDED WITHIN AN AREA OF DEEP MOISTURE THAT COVERS
MOST OF THE GULF AS DEPICTED ON THE TOTAL PRECIPITABLE WATER
IMAGERY. THE WAVE CONTINUES TO BE ILL-DEFINED WITH NO ASSOCIATED
DEEP CONVECTION.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL
ATLC NEAR 17N16W AND CONTINUES ALONG 17N18W THROUGH THE 1010 MB
LOW ASSOCIATED WITH THE TROPICAL WAVE NEAR 18N23W THEN ALONG
12N32W TO 9N41W WHERE THE ITCZ BEGINS AND CONTINUES TO SOUTH
AMERICA NEAR 8N60W. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS WITHIN 120 NM OF LINE FROM 13N20W TO 7N26W...
WITHIN 75/90 NM OF LINE FROM 9N27W TO 8N41W...AND FROM 5N TO THE
ITCZ BETWEEN 45W-48W. CLUSTERS OF SCATTERED MODERATE CONVECTION
ARE FROM THE ITCZ TO 10N W OF 53W TO INLAND OVER SOUTH AMERICA.

...DISCUSSION...

GULF OF MEXICO...
A BROAD UPPER RIDGE ANCHORED OVER CENTRAL TEXAS EXTENDS SE
ACROSS THE GULF TO W TIP OF CUBA GIVING THE GULF N TO E FLOW
ALOFT. AN UPPER TROUGH EXTENDS FROM THE NEW ENGLAND TO NE
FLORIDA SUPPORTING A FRONTAL BOUNDARY THAT IS INLAND OVER THE SE
CONUS. REMNANT SCATTERED SHOWERS/ISOLATED THUNDERSTORMS REMAIN
IN THE N/CENTRAL GULF N OF 27N BETWEEN 90W-92W INCLUDING
PORTIONS OF SE LOUISIANA. WEAK SURFACE RIDGE ANCHORED IN THE
ATLC EXTENDS ACROSS N FLORIDA TO OVER THE GULF. SOME ISOLATED
SHOWERS REMAIN IN THE E BAY OF CAMPECHE S OF 20N BETWEEN 91W-
94W. THIS IS LEAVING THE REMAINDER OF THE GULF UNDER MOSTLY
CLEAR SKIES THIS MORNING. THE N PORTION OF THE TROPICAL WAVE
WILL MOVE ACROSS THE SW GULF TODAY AND TONIGHT. THE WEAK SURFACE
RIDGE WILL REMAIN NEARLY STATIONARY THROUGH SAT THEN SHIFT
SOUTHWARD SUN THROUGH TUE.

CARIBBEAN SEA...
AN UPPER LOW REMAINS CENTERED OVER THE CAYMAN ISLANDS COVERING
THE NW CARIBBEAN AND EXTENDING AN UPPER TROUGH SW TO THE GULF OF
HONDURAS. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE N OF 21N
TO INLAND OVER CUBA BETWEEN 80W-84W AND IN THE GULF OF HONDURAS
S OF S OF 17N W OF 87W. AN UPPER RIDGE COVERS THE SW CARIBBEAN S
OF 18N BETWEEN 69W-82W. A BROAD UPPER TROUGH EXTENDS FROM AN
UPPER LOW OVER THE CENTRAL ATLC ACROSS THE GREATER ANTILLES
BETWEEN THE VIRGIN ISLANDS AND THE DOMINICAN REPUBLIC COVERING
THE E CARIBBEAN. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE
INLAND AND WITHIN 60 NM ALONG THE S COAST OF HISPANIOLA AND IN
THE GULF OF GONAVE E OF 75W. THE MONSOON TROUGH EXTENDS ALONG
10N/11N FROM COLOMBIA TO COSTA RICA GENERATING SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS S OF 13N W OF 76W TO OVER
NICARAGUA. FRESH TO STRONG TRADE WINDS WILL PREVAIL ACROSS THE
CENTRAL CARIBBEAN TODAY THROUGH THE WEEKEND. MODERATE TO FRESH
TRADE WINDS WILL BE ACROSS THE REMAINDER OF THE BASIN.

HISPANIOLA...
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS DOT THE ISLAND THIS
MORNING WITH THE HIGHEST CONCENTRATION OF THUNDERSTORMS WITHIN
60 NM ALONG THE S COAST OF THE DOMINICAN REPUBLIC AND THE N
COAST E OF 71W. THE UPPER TROUGH OVER THE E CARIBBEAN WILL
CONTINUE TO DRIFT W TO OVER HISPANIOLA THROUGH THE FIRST OF NEXT
WEEK. THIS WILL INCREASE AFTERNOON SHOWERS AND THUNDERSTORMS.

ATLANTIC OCEAN...
AN UPPER TROUGH EXTENDS FROM NEW ENGLAND TO OVER NE FLORIDA
SUPPORTING A FRONTAL BOUNDARY INLAND OVER THE SE CONUS. THE
UPPER LOW IN THE NW CARIBBEAN EXTENDS OVER THE W ATLC S OF 27N
BETWEEN 74W-81W SUPPORTING THE SURFACE TROUGH IN THE SPECIAL
FEATURES ABOVE. AN UPPER RIDGE ANCHORED N-NE OF BERMUDA EXTENDS
A RIDGE AXIS S TO THE TURKS AND CAICOS. THIS UPPER RIDGE IS
PROVIDING DIFFLUENCE ALOFT TO GENERATE SCATTERED SHOWERS/
ISOLATED THUNDERSTORMS FROM 21N-26N BETWEEN 71W-75W. A LARGE
UPPER LOW IS IN THE N/CENTRAL ATLC NEAR 33N51W AND EXTENDS AN
UPPER TROUGH SW TO OVER THE E CARIBBEAN. THE REMAINDER OF THE
ATLC IS DOMINATED BY A SURFACE RIDGE ANCHORED BY A 1027 MB W OF
THE AZORES. GOES-R SATELLITE SHOWS A BROAD AREA OF SAHARAN DUST
LAYER COVERING THE TROPICAL ATLC INTO THE E CARIBBEAN E OF 65W.
A SURFACE LOW...POSSIBLY A TROPICAL CYCLONE...MAY DEVELOP ALONG
THE SPECIAL FEATURES SURFACE TROUGH AS IT SLOWLY MOVES NW TO N
THROUGH TONIGHT. THE TROUGH OR LOW WILL THEN MOVE TO THE N-NE
THIS WEEKEND WHILE MERGING WITH A FRONTAL BOUNDARY OFF THE SE
CONUS. THE SURFACE RIDGE WILL DOMINATE THE REMAINDER OF THE
BASIN THROUGH THE TUE. ANOTHER FRONTAL BOUNDARY MAY DROP S OF
31N LATE MON INTO TUE.

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

$$
PAW


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