Atlantic Basin Tropical Discussion Atlantic | Pacific

000
AXNT20 KNHC 221721
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL  
105 PM EST SUN NOV 22 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1645 UTC.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 7N9W 6N22W 3N35W 8N48W 11N53W 
10N63W. ISOLATED MODERATE CONVECTION IS FROM 4N-7N BETWEEN 
18W-25W. SIMILAR ACTIVITY IS FROM 2N-5N BETWEEN 26W-35W...AND 
FROM 6N-8N BETWEEN 40W-47W. A SURFACE TROUGH EXTENDS FROM 18N49W 
TO 9N51W. ISOLATED MODERATE CONVECTION IS TO THE E OF THE AXIS 
FROM 10N-18N BETWEEN 43W-49W.

...DISCUSSION...

GULF OF MEXICO...
AS OF 1500 UTC...A 1013 MB LOW IS LOCATED S OF THE FLORIDA 
PANHANDLE NEAR 30N86W. A WARM FRONT EXTENDS TO THE E ALONG 
31N83W 31N81W. A COLD FRONT EXTENDS TO THE SE FROM THE LOW 
CENTER ALONG 28N85W TURNING S-SW ALONG 26N86W 24N89W BECOMING 
STATIONARY TO 21N93W. MOST OF THE SHOWER ACTIVITY LIES BETWEEN 
THESE TWO FRONTS. RADAR IMAGERY INDICATES SHOWERS/THUNDERSTORMS 
ALONG A SWATH FROM 26N84W ACROSS TAMPA INTO CENTRAL FLORIDA NEAR 
27N81W. A SECOND SWATH OF STRONGER SHOWERS/THUNDERSTORMS EXTENDS 
FROM 28N84W INTO THE BIG BEND OF FLORIDA TO NEAR 30N82W. 
ISOLATED SHOWERS/THUNDERSTORMS ARE WITHIN 100 NM OF THE 
STATIONARY FRONT AND ELSEWHERE BETWEEN THE WARM FRONT AND 
STATIONARY FRONT AFFECTING MUCH OF FLORIDA. AN OCCLUDED FRONT 
EXTENDS W FROM THE LOW CENTER TO A SECOND 1013 MB LOW OVER ERN 
LOUISIANA NEAR 31N90W. A SURFACE TROUGH EXTENDS FROM THIS LOW 
ALONG 29N91W 27N95W. IN THE UPPER LEVELS...MOIST SWLY FLOW 
EXTENDS ACROSS MUCH OF THE GULF AROUND A BROAD UPPER LEVEL 
TROUGH OVER THE CENTRAL CONUS. AN UPPER LEVEL LOW IS EMBEDDED IN 
THE LONGWAVE TROUGH CENTERED OVER TENNESSEE SUPPORTING THE LOW 
PRESSURE AND FRONTAL SYSTEM. A SLOT OF DRY AIR EXTENDS OVER SE 
TEXAS AND THE NW GULF. EXPECT THE LOW PRESSURE SYSTEM TO MOVE NE 
AS THE FRONTAL SYSTEM MOVES E...AND BOTH ARE EXPECTED TO WEAKEN 
OVER THE NEXT 24 HRS. SHOWERS/THUNDERSTORMS ARE EXPECTED OVER 
THE ERN GULF OF MEXICO AS THE LOW/FRONTAL SYSTEM PUSHES E. 

CARIBBEAN SEA...
SIGNIFICANT DRY AIR AND SUBSIDENCE IS ACROSS THE CARIBBEAN 
NOTED IN WATER VAPOR IMAGERY SUPPORTING FAIR WEATHER ACROSS MUCH 
OF THE BASIN. A FEW SHOWERS/THUNDERSTORMS ARE S OF HISPANIOLA 
FROM 17N-18N BETWEEN 70W-74W ASSOCIATED WITH A SURFACE TROUGH N 
OF HISPANIOLA IN THE ATLC. SCATTERED SHOWERS/THUNDERSTORMS ARE 
ALSO ACROSS THE SW CARIBBEAN S OF 12N BETWEEN 79W-85W. THIS 
ACTIVITY IS ENHANCED BY SURFACE CONVERGENCE NEAR THE E PACIFIC 
ITCZ...AS WELL AS DIFFLUENT FLOW ALOFT BETWEEN AN UPPER LEVEL 
TROUGH SW OF CENTRAL AMERICA AND A BROAD UPPER LEVEL RIDGE THAT 
COVERS THE CARIBBEAN. MODERATE TO FRESH TRADEWINDS ARE ACROSS 
MUCH OF THE BASIN WITH STRONGER WINDS IN THE ERN CARIBBEAN AND 
NEAR THE COAST OF COLOMBIA. EXPECT LITTLE CHANGE OVER THE NEXT 
24 HRS. 

ATLANTIC OCEAN...
ISOLATED SHOWERS EXTEND INTO THE FAR WRN ATLC FROM ACROSS 
FLORIDA N OF 27N W OF 75W ASSOCIATED WITH A WARM FRONT EXTENDING 
ACROSS NRN FLORIDA TO NEAR 30N80W. A WEAK 1014 MB SURFACE LOW IS 
NEAR 31N73W WITH A SURFACE TROUGH EXTENDING TO NEAR 29N76W. 
SHOWERS ARE POSSIBLE NEAR THE LOW CENTER. AN UPPER LEVEL RIDGE 
COVERS THE WRN ATLC KEEPING THE REMAINDER OF THE AREA UNDER FAIR 
CONDITIONS...EXCEPT FOR AN AREA OF SHOWERS/THUNDERSTORMS ACROSS 
THE SE BAHAMAS FROM 20N-22N BETWEEN 70W-73W. THIS ACTIVITY IS 
ENHANCED BY SURFACE CONVERGENCE NEAR A SURFACE TROUGH THAT 
EXTENDS ALONG 30N59W S TO 25N62W SW ALONG 23N67W TO NRN 
HISPANIOLA NEAR 20N73W. ISOLATED SHOWERS ARE ALSO WITHIN 200 NM 
E OF THE TROUGH AXIS N OF 25N. FARTHER E...A SURFACE TROUGH 
EXTENDS FROM 30N50W TO 25N48W. SCATTERED SHOWERS/THUNDERSTORMS 
ARE WITHIN 150 NM OF THE TROUGH AXIS. A SECOND SURFACE TROUGH 
EXTENDS FROM THE FAR ERN ATLC ALONG 31N11W 29N22W 27N33W 30N43W. 
ISOLATED SHOWERS ARE ALONG THE AXIS...AND N OF 21N BETWEEN 
40W-45W. SCATTERED SHOWERS/THUNDERSTORMS ARE N OF THE TROUGH 
AXIS FROM 30N-33N BETWEEN 33W-40W. THIS SERIES OF TROUGHS AND 
ASSOCIATED SHOWER ACTIVITY IS SUPPORTED BY AN UPPER LEVEL TROUGH 
IN THE CENTRAL ATLC FROM 26N44W TO 12N51W. DIFFLUENT FLOW 
BETWEEN THIS TROUGH AND AN UPPER LEVEL RIDGE DIRECTLY TO THE N 
OF THE TROUGH IS ALSO ENHANCING THE SHOWER ACTIVITY. ZONAL WLY 
FLOW IS ACROSS THE TROPICAL 
ATLC. 
                                                           
$$
WALTON