[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 211225
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1045 UTC.

...SPECIAL FEATURES...

A 1009 MB ELONGATED LOW IS CENTERED OVER THE TROPICAL EASTERN
ATLC NEAR 11N28W REMAINS THE FOCAL POINT OF A BROAD MONSOONAL
TROUGH S OF 15N BETWEEN 28W-38W. SCATTERED MODERATE TO ISOLATED
STRONG CONVECTION COVERS A BROAD AREA FROM 5N-16N BETWEEN
20W-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 24N44W TO 11N42W MOVING W AT 10-15
KT. NIGHT VISIBLE SATELLITE IMAGERY 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 AND E ATLC. THEREFORE...NO
SIGNIFICANT DEEP ORGANIZED CONVECTION ACCOMPANIES THE WAVE...
HOWEVER ISOLATED SHOWERS ARE WITHIN 20 NM WEST OF THE AXIS N OF
20N AND S OF 14N.

A TROPICAL WAVE EXTENDS FROM 24N64W TO 16N66W MOVING WNW AT
10-15 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. 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 AND MEXICO COAST S OF 23N W OF 92W.

...ITCZ...

THE ITCZ AXIS IS BETTER DEFINED NE OF S AMERICA CENTERED ALONG
11N44W 10N57W 12N70W. EMBEDDED WITHIN THE MONSOONAL TROUGH
MENTIONED IN THE SPECIAL FEATURES SECTION...A 1011 MB LOW IS
CENTERED NEAR 15N22W. SCATTERED MODERATE AND ISOLATED STRONG
CONVECTION IS FROM 5N-16N BETWEEN 20W-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 26N86W.
HOWEVER...SCATTERED SHOWERS AND ISOLATED 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 PREVIOUSLY ALIGNED OVER THE W FLORIDA
COASTLINE FROM 25N TO 30N. 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 SW
CARIBBEAN DUE TO CONVERGENCE IN THE VICINITY OF AN EXTENTION OF
THE ITCZ ALONG 11N CROSSING FROM NORTHERN COLOMBIA TO CENTRAL
NICARAGUA...GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS W OF
74W S OF 15N. 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...
UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED OVER THE SE
CONUS. WITH A FRONTAL BOUNDARY DRAPED NEAR THE NORTHERN EDGE OF
THE DISCUSSION AREA ALONG 32N...WIDELY SCATTERED SHOWERS AND
ISOLATED TSTMS ARE OCCURRING OVER THE W ATLC N OF 28N W OF W OF
73W. SE OF THE UPPER LEVEL ANTICYCLONE...AN MID/UPPER LEVEL LOW
IS CENTERED NEAR 25N68W AND EXTENDS UPPER LEVEL TROUGHING TO 31N
BETWEEN 60W-72W 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
NORTH OF PUERTO RICO. ELSEWHERE ACROSS THE REMAINDER OF THE
CENTRAL AND EASTERN ATLC...SURFACE RIDGING DOMINATES N OF 24N
ANCHORED BY A 1023 MB HIGH CENTERED NEAR 34N22W MAINTAINING
GENERALLY FAIR WEATHER. THE RIDGE AXIS EXTENDS FROM THE HIGH
CENTER TO THE W ATLC NEAR 29N65W.

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

$$

GARCIA




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