[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 302332
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT THU JUL 30 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
2230 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE EXTENDS FROM 25N36W TO 7N38W MOVING W NEAR 20
KT. SATELLITE IMAGERY AND SATELLITE DERIVED WINDS INDICATE A
BROAD LOW/MID-LEVEL CYCLONIC FLOW IN THE VICINITY OF THE WAVE
AXIS. THIS WAVE ALSO LEADS A HIGH AMPLITUDE DEEP LAYER MOISTURE
MAXIMUM OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. DRY AIR
AND SAHARAN DUST IS NE AND W OF THE WAVE INHIBITING DEEP
CONVECTION. HOWEVER...SCATTERED SHOWERS REMAIN EMBEDDED WITHIN
THE ITCZ AXIS S OF 12N.

A TROPICAL WAVE IS ALONG 67W/68W S OF 20N MOVING W NEAR 20 KT.
THIS WAVE COINCIDES WITH A DEEP LAYER MOISTURE MAXIMUM OBSERVED
IN TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE
CONVECTION IS FROM 7N-10N BETWEEN 65W-68W OVER NRN VENEZUELA.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 12N-17N
BETWEEN 65W-72W.

A TROPICAL WAVE IS ALONG 96W S OF 20N MOVING W NEAR 20 KT. THE
MAJORITY OF THIS WAVE LIES IN THE E PACIFIC. REFER TO THE TWDEP
FOR MORE DETAILS.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 13N17W 12N37W 10N50W 11N66W AND
ACROSS NRN S AMERICA TO 9N74W. SCATTERED MODERATE/ISOLATED
STRONG CONVECTION IS FROM 10N-16N BETWEEN 15W-17W. SIMILAR
CONVECTION IS FROM 10N-13N BETWEEN 25W-28W...AND FROM 8N-11N
BETWEEN 57W-59W.

...DISCUSSION...

GULF OF MEXICO...
SCATTERED SHOWERS ARE ACROSS THE NRN GULF N OF 28N BETWEEN
86W-93W...AND THE FAR ERN GULF N OF 25N E OF 84W. THIS SHOWER
ACTIVITY IS ENHANCED BY MOISTURE ALOFT AND UPPER LEVEL
DIFFLUENCE BETWEEN AN UPPER LEVEL HIGH OVER NE FLORIDA NEAR
30N81W AND AN UPPER LEVEL TROUGH OVER THE CENTRAL UNITED STATES.
ELSEWHERE...A WEAK SURFACE RIDGE IS ACROSS THE REMAINDER OF GULF
OF MEXICO ALONG 26N BRINGING GENERALLY FAIR WEATHER ACROSS THE
AREA. ANTI-CYCLONIC SURFACE WINDS ARE AROUND THE SURFACE RIDGE
REACHING 20 KT IN THE WRN GULF. DRY AIR AND SUBSIDENCE ALOFT ARE
SUPPORTING THE FAIR WEATHER. EXPECT SHOWERS/THUNDERSTORMS TO
CONTINUE ALONG THE NRN GULF AND FLORIDA OVER THE NEXT 24 HRS.

CARIBBEAN SEA...
DRY AND SUBSIDENT AIR ALOFT IS SUPPORTING GENERALLY FAIR
WEATHER ACROSS THE WRN AND CENTRAL CARIBBEAN. SCATTERED
SHOWERS/THUNDERSTORMS ARE ACROSS THE S CENTRAL CARIBBEAN S OF
15N W OF 77W INCLUDING MUCH OF NICARAGUA AND COSTA RICA. THIS
ACTIVITY IS ENHANCED BY UPPER LEVEL DIFFLUENT FLOW AND SURFACE
CONFLUENCE NEAR THE E PACIFIC ITCZ. SCATTERED
SHOWERS/THUNDERSTORMS ARE ALSO ACROSS THE ERN CARIBBEAN E OF 72W
INFLUENCED BY THE TROPICAL WAVE ALONG 67W/68W. FRESH TO STRONG
TRADE WINDS ARE OVER MUCH OF THE CARIBBEAN WITH THE HIGHEST
WINDS NEAR THE COAST OF COLUMBIA. EXPECT THE SHOWER ACTIVITY IN
THE ERN CARIBBEAN TO MOVE WWD AS THE TROPICAL WAVE PROPAGATES W.

ATLANTIC OCEAN...
ISOLATED SHOWERS/THUNDERSTORMS ARE OVER THE FAR W ATLC N OF A
LINE FROM 24N80W TO 31N72W. THIS ACTIVITY IS ENHANCED BY UPPER
LEVEL DIFFLUENCE BETWEEN AN UPPER LEVEL HIGH OVER NE FLORIDA
NEAR 30N81W AND A SHORTWAVE UPPER LEVEL TROUGH ALONG 73W.
ELSEWHERE ACROSS THE ATLC...A BROAD SURFACE RIDGE DOMINATES
ANCHORED BY A 1026 MB HIGH NEAR 34N55W BRINGING GENERALLY FAIR
WEATHER ACROSS THE BASIN. HOWEVER...SCATTERED SHOWERS ARE JUST
OFF THE COAST OF AFRICA FROM 21N-26N E OF 20W DUE TO UPPER LEVEL
DIFFLUENCE BETWEEN AN UPPER LEVEL LOW NEAR 24N21W AND AN UPPER
LEVEL HIGH OVER AFRICA NEAR 20N10W. ACROSS THE TROPICAL
ATLC...AN UPPER LEVEL RIDGE IS S OF 24N CENTERED NEAR
18N44W...ENHANCING CONVECTION ALONG THE ITCZ.

$$
WALTON




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