[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 301045
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT TUE JUN 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE IS ALONG 24W S OF 14N MOVING W  10-15 KT. THIS
WAVE COINCIDES WITH A DEEP MOISTURE MAXIMUM BASED ON TOTAL
PRECIPITABLE WATER IMAGERY. WHILE NO CONVECTION IS CURRENTLY
ASSOCIATED WITH THE WAVE...SATELLITE IMAGERY INDICATES LOW LEVEL
CYCLONIC FLOW IN THE VICINITY OF THE WAVE.

A TROPICAL WAVE IS ALONG 51W S OF 13N MOVING W 10-15 KT. THIS
WAVE ALSO COINCIDES WITH A DEEP MOISTURE MAXIMUM BASED ON TOTAL
PRECIPITABLE WATER IMAGERY. THIS WAVE ALSO LACKS ANY DEEP
CONVECTION...HOWEVER SCATTERED SHOWERS ARE FROM 10N-12N BETWEEN
49W-53W.

A TROPICAL WAVE IS ALONG 89W S OF 19N MOVING W 15-20 KT. THIS
WAVE HAS BEEN MOVED AHEAD AT A FASTER RATE TO COINCIDE WITH LOW
LEVEL CYCLONIC TURNING APPARENT IN THE E PACIFIC. THE WAVE STILL
REMAINS ILL-DEFINED ON SATELLITE IMAGERY OVER THE YUCATAN
PENINSULA. THE WAVE LIES UNDER AN AREA OF UPPER LEVEL DIFFLUENCE
WHICH IS ENHANCING SCATTERED MODERATE CONVECTION OVER CENTRAL
AMERICA AND MEXICO FROM 14N-19N BETWEEN 89W-93W. SEE ALSO THE
TWDEP FOR MORE INFORMATION ON THIS WAVE.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 11N14W 8N21W 5N30W 4N48W.
SCATTERED MODERATE CONVECTION IS FROM 3N-8N BETWEEN 13W-21W.
ISOLATED MODERATE CONVECTION IS WITHIN 100 NM EITHER SIDE OF THE
AXIS BETWEEN 27W-44W.

...DISCUSSION...

GULF OF MEXICO...
 A STATIONARY FRONT ENTERS THE AREA NEAR 31N86W AND FOLLOWS THE
COASTLINE INTO TEXAS NEAR 30N95W. A SURFACE TROUGH OVER THE E
GULF OF MEXICO AHEAD OF THE FRONT EXTENDS FROM 24N89W TO
27N85W.LOW LEVEL CONVERGENCE NEAR THESE SURFACE FEATURES...ALONG
WITH UPPER LEVEL DIFFLUENCE BETWEEN AN UPPER LEVEL HIGH OVER THE
BAY OF CAMPECHE NEAR 20N95W AND AN UPPER LEVEL LOW IN THE
CENTRAL CARIBBEAN NEAR 17N75W...ARE SUPPORTING SCATTERED SHOWERS
AND THUNDERSTORMS ACROSS THE NE GULF OF MEXICO FROM 27N-30N
BETWEEN 83W-91W. ISOLATED SHOWERS AND POSSIBLE THUNDERSTORMS ARE
ALSO ACROSS THE MAJORITY OF THE E GULF INCLUDING THE FLORIDA
PENINSULA AND THE STRAITS OF FLORIDA N OF 22N E OF 91W.
ATMOSPHERIC INSTABILITY FROM THE TROPICAL WAVE OVER THE YUCATAN
IS ALSO ENHANCING THIS ACTIVITY AS WELL AS SCATTERED SHOWERS AND
THUNDERSTORMS IN THE FAR SW BAY OF CAMPECHE S OF 20N W OF 95W.
ACROSS THE REMAINDER OF THE GULF OF MEXICO...SUBSIDENCE
RESULTING FROM UPPER LEVEL CONFLUENCE AROUND AN UPPER LEVEL
RIDGE ASSOCIATED WITH THE UPPER LEVEL HIGH OVER THE BAY OF
CAMPECHE ALONG WITH DEEP LAYER DRY AIR ARE RESULTING IN
GENERALLY FAIR WEATHER ACROSS THE NW GULF.

CARIBBEAN SEA...
THE WAVE THAT WAS IN THE W CARIBBEAN HAS NOW MOVED OVER THE
YUCATAN PENINSULA. THE WAVE IS ENHANCING ISOLATED SHOWERS ACROSS
THE YUCATAN CHANNEL. THE REST OF THE W CARIBBEAN IS EXPERIENCING
GENERALLY FAIR WEATHER. AN AREA OF SCATTERED SHOWERS AND
THUNDERSTORMS ARE IN THE CENTRAL CARIBBEAN FROM 15N-17N BETWEEN
76W-79W. THIS SHOWER ACTIVITY IS BEING SUPPORTED BY UPPER LEVEL
DIFFLUENCE IN NLY FLOW ALOFT AROUND AN UPPER LEVEL LOW OVER THE
CENTRAL CARIBBEAN NEAR 17N75W. ACROSS THE E CARIBBEAN...UPPER
LEVEL RIDGING IS E OF 70W RESULTING IN GENERALLY FAIR WEATHER
WITH THE EXCEPTION OF A FEW ISOLATED SHOWERS. FRESH TO STRONG
EASTERLY TRADE WINDS ARE ACROSS THE E CARIBBEAN. EXPECT THE
TRADES TO PERSIST THROUGH THE WEEK.

ATLANTIC OCEAN...
ACROSS THE SW NORTH ATLC...DIFFLUENCE IN NWLY FLOW ALOFT IS
INTERACTING WITH DEEP LAYER MOISTURE TO SUPPORT A SURFACE TROUGH
EXTENDING FROM 24N73W TO 27N70W. SURFACE CONVERGENCE NEAR THIS
TROUGH AS WELL AS THE UPPER LEVEL DIFFLUENCE ARE SUPPORTING
ISOLATED SHOWERS AND THUNDERSTORMS N OF 22N W OF 75W INCLUDING
THE BAHAMAS AND STRAITS OF FLORIDA. AN AREA OF SCATTERED SHOWERS
AND THUNDERSTORMS ARE OVER THE NRN BAHAMAS FROM 25N-27N BETWEEN
76W-79W. NASSAU HAS REPORTED .45 INCHES OF RAIN OVER THE PAST 24
HRS. A SURFACE TROUGH N OF THE DISCUSSION AREA IS SUPPORTING
ISOLATED SHOWERS AND THUNDERSTORMS N OF 28 N BETWEEN 57W-64W.
FARTHER TO THE E...A PAIR OF SURFACE HIGHS DOMINATE BRINGING
GENERALLY FAIR WEATHER ACROSS THE CENTRAL AND E ATLC. A 1020 MB
HIGH IS CENTERED NEAR 29N42W AND A 1021 MB HIGH IS CENTERED NEAR
31N19W. IN THE UPPER LEVELS...A BROAD RIDGE IS OVER THE FAR W
ATLC S OF 32N W OF 50W. TO THE E AN UPPER LEVEL TROUGH EXTENDS
FROM 20N50W TO 31N35W...FOLLOWED BY A SECOND UPPER LEVEL RIDGE E
OF 35W. A BROAD UPPER LEVEL RIDGE IS S OF 20N. ACROSS THE
TROPICAL ATLC...MOIST E-NE FLOW ALOFT AROUND THE BASE OF THE
UPPER LEVEL RIDGE IS PRESENT AND SUPPORTING ACTIVITY ALONG THE
ITCZ.

$$
WALTON




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