[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 210552
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT SAT AUG 21 2010

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...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND
RADAR.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0545 UTC.

...SPECIAL FEATURES...

A 1009 MB ELONGATED LOW IS CENTERED OVER THE TROPICAL EASTERN
ATLC NEAR 11N27W THAT REMAINS THE FOCAL POINT OF A BROAD
MONSOONAL TROUGH S OF 14N BETWEEN 20W-39W. SCATTERED MODERATE TO
ISOLATED STRONG CONVECTION COVERS A BROAD AREA FROM 5N-15N
BETWEEN THE WEST COAST OF AFRICA AND 40W. WHILE CONVECTION
REMAINS GENERALLY UNORGANIZED...THE UPPER LEVEL ENVIRONMENT FOR
TROPICAL CYCLONE DEVELOPMENT IS FAVORABLE FOR DEVELOPMENT AND A
TROPICAL DEPRESSION COULD FORM DURING THE NEXT COUPLE OF DAYS.
THERE IS A MEDIUM CHANCE OF THIS SYSTEM BECOMING A TROPICAL
CYCLONE DURING THE NEXT FEW DAYS AS IT MOVES SLOWLY WESTWARD.

...TROPICAL WAVES...

TROPICAL WAVE EXTENDS FROM 11N44W TO 11N42W MOVING W AT 10-15
KT. NIGHT VISIBLE SATELLITE INDICATES WEAK LOW-LEVEL CYCLONIC
TURNING ALONG THE WAVE AXIS AND THIS WAS ALSO NOTED ON SATELLITE
DERIVED WINDS. AN AREA OF MAXIMUM DEEP LAYER MOISTURE IS
OBSERVED ON THE TPW IMAGERY EMBEDDED IN THE WAVE. HOWEVER..MUCH
OF THIS MOISTURE IS POSITIONED BENEATH A STABLE SAHARAN AIR
LAYER THAT COVERS MUCH OF THE CENTRAL A ND E ATLC. THEREFORE NO
SIGNIFICANT DEEP ORGANIZED CONVECTION ACCOMPANIES THE WAVE...
HOWEVER ISOLATED SHOWERS ARE WITHIN 20 NM OF THE AXIS N OF 20N
AND S OF 14N.

A TROPICAL WAVE EXTENDS FROM 25N67W TO 14N64W MOVING W AT 15-20
KT. THE WAVE COINCIDES WITH A MID/UPPER LEVEL LOW CENTERED NEAR
25N68W. MODERATE TOTAL PRECIPITABLE WATER VALUES ACCOMPANY THIS
SYSTEM N OF 17N...AS THIS MOISTURE CONTINUES TO ADVECT NORTHWARD
DUE TO A WEAKNESS IN THE SUBTROPICAL RIDGE BETWEEN 60W-70W.
ISOLATED MODERATE CONVECTION AND WIDELY SCATTERED SHOWERS ARE
OCCURRING FROM 17N-24N BETWEEN 62W-70W. NO DEEP CONVECTION IS
OBSERVED AT THE MOMENT DUE TO THE LACK OF SUFFICIENT LOW-LEVEL
MOISTURE. ONLY A FEW ISOLATED SHOWERS ARE NOTED WITHIN 30 NM IN
THE VICINITY OF THE WAVE AXIS NORTH OF PUERTO RICO.

TROPICAL WAVE IS OVER THE SW GULF OF MEXICO EXTENDING FROM
23N96W TO 13N92W MOVING W AT 5-10 KT. LOW-LEVEL CYCLONIC FLOW IS
IN THE VICINITY OF THE WAVE...NOTED ON THE NIGHT VISIBLE
SATELLITE IMAGERY. LOW-LEVEL SURFACE CONVERGENCE ALONG WITH
PLENTY OF LOW-LEVEL MOISTURE IS GENERATING A LARGE AREA OF
SCATTERED MODERATE AND ISOLATED STRONG CONVECTION OVER MUCH OF
THE BAY OF CAMPECHE S OF 23N W OF 90W AND INLAND OVER SRN MEXICO.

...ITCZ...

THE ITCZ AXIS IS BETTER DEFINED NE OF S AMERICA CENTERED ALONG
12N43W 10N51W 12N63W. EMBEDDED WITHIN THE MONSOONAL TROUGH
MENTIONED IN THE SPECIAL FEATURES SECTION...A 1009 MB LOW IS
CENTERED NEAR 11N27W. SCATTERED MODERATE AND ISOLATED STRONG
CONVECTION IS FROM 5N-15N BETWEEN THE WEST COAST OF AFRICA AND
40W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL RIDGE COVERS MOST OF THE GULF OF MEXICO. WATER
VAPOR IMAGERY SHOWS A MID/UPPER LEVEL DRY AIRMASS MOVING
WESTWARD ACROSS MUCH OF THE BASIN TONIGHT...PROVIDING STABLE
CONDITIONS ACROSS THE AREA. THIS UPPER LEVEL RIDGE SUPPORTS A
1016 MB HIGH CENTERED OVER THE NE BASIN NEAR 27N86W. HOWEVER...A
FEW SHOWERS AND THUNDERSTORMS STILL REMAIN OVER THE FAR E AND SE
GULF AFFECTING THE W COASTAL WATERS OF THE FLORIDA PENINSULA
INCLUDING THE FLORIDA KEYS...FROM A WEAK SURFACE TROUGH ALIGNED
OVER THE W FLORIDA COASTLINE FROM 25N TO 29N. THE SW GULF IS
UNDER THE INFLUENCE OF A TROPICAL WAVE ALONG 95W IMPACTING THE
BAY OF CAMPECHE S OF 23N W OF 90W WITH SCATTERED SHOWERS AND
TSTMS.

CARIBBEAN SEA...
ABUNDANT MOISTURE AND INSTABILITY IS NOTED ACROSS THE INTERIOR
CENTRAL AMERICA AND SURROUNDING WATERS COVERING THE SW CARIBBEAN
GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS W OF 74W S OF
17N. SATELLITE IMAGERY DENOTES THE STRONGEST ACTIVITY LIES
WITHIN 100 NM OFFSHORE OF WESTERN PANAMA...COSTA RICA...
NICARAGUA...AND HONDURAS. FARTHER EAST...WATER VAPOR IMAGERY
SHOWS A MID/UPPER LEVEL DRY AIRMASS ACROSS MUCH OF THE BASIN E
OF 74W...PROVIDING STABLE CONDITIONS ACROSS THE AREA.
HOWEVER...IN THIS REGION OF DRY AND STABLE AIR...A TROPICAL WAVE
IS ANALYZED MOVING OVER PUERTO RICO ALONG 66W WITH NO ASSOCIATED
DEEP CONVECTION DUE TO THE LACK OF LOW-LEVEL MOISTURE. ONLY A
FEW ISOLATED SHOWERS ARE NOTED WITHIN 30 NM IN THE VICINITY OF
THE WAVE AXIS NORTH OF PUERTO RICO.

ATLANTIC OCEAN...
A WEAK 1015 MB HIGH IS CENTERED OVER THE NW BAHAMAS NEAR 26N76W
THAT RESIDES ON THE SE PERIPHERY OF AN ANTICYCLONIC CIRCULATION
CENTERED OVER THE SE CONUS. WITH A FRONTAL BOUNDARY DRAPED NEAR
THE NORTHERN EDGE OF THE DISCUSSION AREA ALONG 31N...WIDELY
SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING OVER THE W
ATLC N OF 29N W OF W OF 71W. SE OF THE UPPER LEVEL ANTICYCLONE
...AN MID/UPPER LEVEL LOW IS CENTERED NEAR 25N68W AND EXTENDS
UPPER LEVEL TROUGHING TO 30N BETWEEN 60W-70W AND SOUTHWARD INTO
THE NE CARIBBEAN SEA. A TROPICAL WAVE IS ALONG 66W WITH NO
ASSOCIATED DEEP CONVECTION DUE TO THE LACK OF LOW-LEVEL
MOISTURE. ONLY A FEW ISOLATED SHOWERS ARE NOTED WITHIN 30 NM IN
THE VICINITY OF THE WAVE AXIS. ELSEWHERE ACROSS THE REMAINDER OF
THE CENTRAL AND EASTERN ATLC...SURFACE RIDGING DOMINATES N OF
25N ANCHORED BY A 1022 MB HIGH CENTERED NEAR 32N27W MAINTAINING
GENERALLY FAIR WEATHER. THE RIDGE AXIS EXTENDS FROM THE HIGH
CENTER TO THE W ATLC NEAR 26N65W.

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

$$

GARCIA



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