[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 062350
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT THU AUG 06 2009

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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE IS ALONG 32W S OF 17N MOVING W NEAR 13 KT. THIS
WAVE COINCIDES WITH A DEEP LAYER MOISTURE MAXIMUM OBSERVED IN
TOTAL PRECIPITABLE WATER IMAGERY. ISOLATED MODERATE CONVECTION
IS FROM 13N-15N BETWEEN 30W-34W.

A TROPICAL WAVE IS ALONG 49W S OF 14N MOVING W NEAR 18 KT. THIS
WAVE REMAINS ON THE LEADING EDGE OF DRY SAHARAN AIR AND DUST
INHIBITING DEEP CONVECTION ALONG THE WAVE AXIS. HOWEVER...
SCATTERED SHOWERS ARE FROM 10N-12N BETWEEN 46W-50W.

A TROPICAL WAVE IS ALONG 66W S OF 18N MOVING W NEAR 15 KT. THIS
WAVE COINCIDES WITH A DEEP LAYER MOISTURE MAXIMUM THAT STRETCHES
NWD INTO THE SW NORTH ATLC DUE TO AN UPPER LEVEL LOW CENTERED
NEAR 23N67W. INTERACTIONS BETWEEN THE TROPICAL WAVE AND UPPER
LEVEL LOW ARE PRODUCING SCATTERED SHOWERS AND ISOLATED MODERATE
CONVECTION FROM 10N-19N BETWEEN 60W-70W.

A TROPICAL WAVE IS ALONG 82W S OF 21N MOVING W NEAR 15 KT. THIS
WAVE LIES IN A BROAD AREA OF DEEP LAYER MOISTURE OBSERVED IN
TOTAL PRECIPITABLE WATER IMAGERY. THIS WAVE CONTINUES MOVING
BENEATH A DIFFLUENT PATTERN ALOFT ENHANCING SCATTERED MODERATE
CONVECTION OVER THE SW CARIBBEAN S OF 12N AND ACROSS PANAMA AND
COSTA RICA. ALSO SCATTERED MODERATE/ISOLATED STRONG CONVECTION
IS OVER THE NW CARIBBEAN N OF 18N BETWEEN 80W-89W...INCLUDING
PORTIONS OF WRN CUBA AND THE YUCATAN PENINSULA.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 11N16W 11N21W 13N31W 13N34W
12N40W 10N43W 8N48W 7N50W AND INTO NRN SOUTH AMERICA NEAR 6N55W.
CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE
FROM 9N-15N BETWEEN 13W-24W. SCATTERED MODERATE CONVECTION IS
FOCUSED ALONG A SURFACE TROUGH EMBEDDED WITHIN THE ITCZ THAT
EXTENDS FROM 16N39W TO 9N42W. THIS CONVECTION IS LOCATED FROM
11N-15N BETWEEN 39W-45W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL TROUGH IS ACROSS THE SE CONUS AND EXTENDS SW INTO
THE GULF OF MEXICO TO AN UPPER LOW CENTERED NEAR 23N91W. THIS
UPPER LEVEL FEATURE IS SUPPORTING A WEAK SURFACE TROUGH THAT
EXTENDS FROM SE GEORGIA INTO THE NE GULF ALONG 30N84W 26N90W TO
26N93W. WEAK LOW-LEVEL CONVERGENCE OF PRIMARILY NE WINDS ACROSS
MUCH OF THE GULF ARE GENERATING SCATTERED SHOWERS AND ISOLATED
TSTMS OVER A BULK OF THE GULF WATERS. LIGHTNING DATA PLACES MOST
OF THIS ACTIVITY FROM 24N-28N BETWEEN 84W-94W. ALSO...
ATMOSPHERIC INSTABILITY SE OF THE SURFACE TROUGH IS GENERATING
SCATTERED SHOWERS AND TSTMS ACROSS INTERIOR PORTIONS OF THE
FLORIDA PENINSULA N OF 27N. WITH THE UPPER LEVEL LOW CENTERED
OVER THE S/CENTRAL GULF...UPPER LEVEL DIFFLUENCE ALONG WITH THE
PRESENCE OF THE TROPICAL WAVE ALONG 82W IN THE NW CARIBBEAN IS
GENERATING SCATTERED SHOWERS AND TSTMS OVER WRN CUBA...THE
STRAITS OF FLORIDA...YUCATAN PENINSULA AND NEARBY COASTAL WATERS.

CARIBBEAN SEA...
TWO TROPICAL WAVES ARE TRACKING WWD ACROSS THE CARIBBEAN BASIN.
ONE IS LOCATED ALONG 82W WITH AN UPPER LEVEL DIFFLUENT PATTERN
PRESENT OVER THE WRN CARIBBEAN. SCATTERED SHOWERS AND TSTMS ARE
S OF 16N AND W OF A LINE FROM 16N82W TO 11N74W OVER NRN
COLOMBIA. HEAVY RAINFALL AND POSSIBLE FLOODING IS EXPECTED OVER
INTERIOR PORTIONS OF COSTA RICA...NICARAGUA...AND HONDURAS
DURING THE NEXT 24-36 HOURS AS THE WAVE CONTINUES WWD. THE NRN
PORTION OF THE TROPICAL WAVE IS GENERATING SCATTERED SHOWERS AND
TSTMS N OF 18N BETWEEN 80W-89W...AS UPPER LEVEL DIFFLUENCE E OF
AN UPPER LOW OVER THE SW GULF OF MEXICO IS HELPING TO SUPPORT
THE CONVECTION OVER THE NW CARIBBEAN...CUBA AND THE YUCATAN
PENINSULA. THE OTHER TROPICAL WAVE IS ALONG 66W AND IS IMPACTING
THE ERN CARIBBEAN WITH SCATTERED SHOWERS AND ISOLATED TSTMS E OF
70W. IN BETWEEN THESE TWO TROPICAL WAVES MIDDLE TO UPPER LEVEL
DRY AIR IN SUBSIDENCE PREVAILS AS UPPER TROUGHING EXTENDS FROM
AN UPPER LEVEL LOW LOCATED N OF PUERTO RICO NEAR 23N67W TO THE
DE LA GUAJIRA PENINSULA IN NRN COLOMBIA. FRESH TO STRONG TRADE
WINDS ARE ACROSS THE CARIBBEAN WITH THE HIGHEST WINDS NEAR THE
COAST OF COLOMBIA.

ATLANTIC OCEAN...
UPPER LEVEL DIFFLUENCE ASSOCIATED WITH AN UPPER LEVEL
ANTICYCLONE CENTERED OVER THE NW BAHAMAS NEAR 25N77W IS
SUPPORTING SCATTERED SHOWERS AND TSTMS OVER NRN FLORIDA N OF 27N
AND THE ADJACENT COASTAL WATERS ALONG THE NERN FLORIDA COAST.
ISOLATED SHOWERS EXTEND NE WITHIN 90 NM EITHER SIDE OF A LINE
FROM 29N78W TO BEYOND 32N73W. FARTHER TO THE E...AN UPPER LEVEL
LOW IS CENTERED NEAR 23N67W. A SURFACE TROUGH IS ANALYZED IN THE
VICINITY OF THIS UPPER LOW AND EXTENDS FROM 30N66W TO 23N69W.
SCATTERED SHOWERS COVER THE AREA FROM 18N-32N BETWEEN 63W-72W.
ELSEWHERE ACROSS THE CENTRAL AND ERN ATLC...A BROAD SURFACE
RIDGE REMAINS IN CONTROL ANCHORED BY A 1027 MB SURFACE HIGH
CENTERED NEAR 33N50W BRINGING GENERALLY FAIR WEATHER ACROSS THE
REMAINDER OF THE BASIN E OF 62W. THE REMAINDER OF THE TROPICAL
ATLC IS UNDER A BROAD UPPER LEVEL RIDGE WITH AXIS ALONG 14N THAT
IS ENHANCING CONVECTION ALONG THE ITCZ AND SURFACE TROUGH NEAR
41W.

$$
HUFFMAN




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