Atlantic Tropical Weather Discussion

000
AXNT20 KNHC 041134
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SAT JUL 04 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 
0945 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE EXTENDS FROM 20N45W TO 5N48W MOVING W 25-30 KT.
THIS WAVE COINCIDES WITH A HIGH AMPLITUDE DEEP LAYER MOISTURE 
MAXIMUM OBSERVED ON TOTAL PRECIPITABLE WATER IMAGERY. SATELLITE 
IMAGERY INDICATES AN INVERTED-V CLOUD SIGNATURE IN THE VICINITY 
OF THE WAVE AXIS S OF 11N. ISOLATED MODERATE CONVECTION IS FROM 
10N-11N BETWEEN 47W-49W.

A TROPICAL WAVE IS ALONG 66W S OF 20N MOVING W NEAR 25 KT. THIS 
WAVE COINCIDES WITH A DEEP LAYER MOISTURE MAXIMUM OBSERVED ON 
TOTAL PRECIPITABLE WATER IMAGERY. DEEP CONVECTION HAS TAPERED 
OFF OVER THE PAST FEW HOURS. ISOLATED MODERATE CONVECTION 
REMAINS OVER VENEZUELA FROM 4N-9N BETWEEN 64W-69W. 

A TROPICAL WAVE IS ALONG 85W S OF 18N MOVING W 20-25 KT. 
SCATTERED MODERATE/ISOLATED STRONG CONVECTION CONTINUES TO BE 
ENHANCED BY UPPER LEVEL DIFFLUENCE ASSOCIATED WITH AN UPPER 
LEVEL RIDGE ACROSS THE SW CARIBBEAN AND CENTRAL AMERICA...AS 
WELL AS SURFACE CONVERGENCE FROM A PORTION OF THE E PACIFIC 
ITCZ. THIS CONVECTION IS MAINLY OVER THE E PACIFIC S OF 11N W OF 
82W.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 12N16W 8N26W 6N42W 9N50W AND 
INTO S AMERICA NEAR 7N60W. SCATTERED MODERATE CONVECTION IS 
WITHIN 100 NM EITHER SIDE OF THE AXIS BETWEEN 18W-27W AND FROM 
5N-7N BETWEEN 55W-57W. 

...DISCUSSION...

GULF OF MEXICO...
A STATIONARY FRONT IS OVER THE FLORIDA PANHANDLE ALONG 31N81W TO 
30N89W. THIS FRONT IS SUPPORTED BY AN UPPER LEVEL TROUGH WITH 
AXIS JUST E OF THE ERN UNITED STATES COASTLINE INTO THE NE GULF 
NEAR 27N84W. SURFACE CONVERGENCE NEAR THE FRONT IS SUPPORTING 
ISOLATED SHOWERS/THUNDERSTORMS WITHIN 150 NM S OF THE FRONT. 
UPPER LEVEL DIFFLUENCE BETWEEN AN UPPER LEVEL LOW OVER THE NW 
CARIBBEAN NEAR 20N85W AND AN UPPER LEVEL RIDGE OVER MEXICO IS 
SUPPORTING SCATTERED SHOWERS/THUNDERSTORMS IN THE BAY OF 
CAMPECHE S OF 22N W OF 94W. A 1018 MB STATIONARY HIGH NEAR 
25N86W DOMINATES THE REMAINDER OF THE GULF OF MEXICO BRINGING  
GENERALLY FAIR WEATHER AND LIGHT WINDS WITH ENHANCED SELY 
SURFACE WINDS UP TO 20 KT IN THE NW PORTION OF THE GULF. EXPECT 
THE SURFACE RIDGE TO PERSIST OVER THE NEXT FEW DAYS.

CARIBBEAN SEA...
TWO TROPICAL WAVES ARE IMPACTING THE CARIBBEAN...SEE ABOVE. 
SCATTERED SHOWERS/THUNDERSTORMS ARE OCCURRING OVER 
CUBA...HAITI...AND THE ADJACENT WATERS N OF 18N BETWEEN 73W-81W. 
THIS ACTIVITY IS SUPPORTED BY ATMOSPHERIC INSTABILITY AND UPPER 
LEVEL DIFFLUENCE BETWEEN AN UPPER LEVEL LOW OVER THE NW 
CARIBBEAN NEAR 20N85W AND AN UPPER LEVEL RIDGE OVER THE WRN 
ATLC. SURFACE CONVERGENCE NEAR A 1010 MB SURFACE LOW OVER PANAMA 
NEAR 9N79W IS SUPPORTING SCATTERED SHOWERS/THUNDERSTORMS S OF 
10N BETWEEN 76W-82W. ELY TRADE WINDS OF 20-30 KT COVER THE 
MAJORITY OF THE CARIBBEAN.  

ATLANTIC OCEAN...
AN UPPER LEVEL TROUGH EXTENDS DOWN THE ERN UNITED STATES 
COASTLINE EXTENDING ACROSS FLORIDA INTO THE NE GULF OF MEXICO. 
THIS UPPER TROUGH SUPPORTS A COLD FRONT THAT ENTERS THE 
DISCUSSION AREA NEAR 32N75W TO 31N80W WHERE IS TRANSITIONS TO A 
STATIONARY FRONT ACROSS THE FLORIDA PANHANDLE. THE FRONTS ARE 
SUPPORTING ISOLATED SHOWERS/THUNDERSTORMS N OF 28N BETWEEN 
70W-78W. FARTHER TO THE E...AN UPPER LEVEL HIGH NEAR 30N57W IS 
SUPPORTING A 1022 MB SURFACE HIGH CENTERED NEAR 28N61W BRINGING 
GENERALLY FAIR WEATHER N OF 20N BETWEEN 50W-70W. A 1012 MB 
SURFACE LOW IS AT THE EDGE OF THE DISCUSSION AREA NEAR 32N40W. A 
SURFACE TROUGH EXTENDS AHEAD OF THE LOW CENTER ALONG 30N38W TO 
26N44W. A SHORTWAVE UPPER LEVEL TROUGH SUPPORTS THE SURFACE LOW 
AND SURFACE TROUGH. LOW-LEVEL CONVERGENCE NEAR THE SURFACE 
TROUGH IS SUPPORTING SCATTERED SHOWERS/THUNDERSTORMS FROM 
27N-30N BETWEEN 36W-40W AND FROM 31N-35N BETWEEN 35W-38W. THE 
ERN ATLC IS DOMINATED BY A SURFACE RIDGE ANCHORED BY A 1022 MB 
HIGH CENTERED NEAR 32N25W THAT IS PRODUCING AN AREA OF STRONG 
N-NE WINDS OF UP TO 30 KT ALONG THE NW AFRICA COAST FROM 26N-33N 
E OF 16W.

$$
WALTON