Atlantic Basin Tropical Discussion Atlantic | Pacific

000
AXNT20 KNHC 211749
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL  
105 PM EST SAT NOV 21 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 
1715 UTC.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 7N12W 5N26W 6N46W 7N50W 7N62W. 
WIDELY SCATTERED MODERATE CONVECTION IS FROM 4N-8N BETWEEN 
9W-20W. SIMILAR CONVECTION IS FROM 3N-8N BETWEEN 25W-42W. A 
SURFACE TROUGH EMBEDDED WITHIN THE ITCZ AXIS IS ANALYZED FROM 
14N44W TO 6N49W. SCATTERED SHOWERS AND ISOLATED MODERATE 
CONVECTION IS FROM 5N-14N BETWEEN 42W-50W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL SHORTWAVE TROUGH IS PROGRESSING EASTWARD OVER NE 
TEXAS AND WESTERN LOUISIANA AND SUPPORTS A 1009 MB LOW CENTERED 
IN THE NW GULF WATERS NEAR 28N94W. A COLD FRONT EXTENDS S FROM 
THE LOW ALONG 28N93W 25N93W TO NEAR TUXPAN MEXICO. A WARM FRONT 
ALSO EXTENDS EAST FROM THE LOW TO 26N87W. LOW-LEVEL CONVERGENCE 
NEAR THE FRONTS ALONG WITH A ZONE OF MIDDLE TO UPPER LEVEL 
DIFFLUENCE LOCATED EAST OF THE UPPER LEVEL TROUGH AXIS IS 
GENERATING NUMEROUS SHOWERS AND SCATTERED TSTMS N OF 25N BETWEEN 
88W-92W...AND WITHIN 60 NM E OF THE COLD FRONT S OF 25N. THE LOW 
IS FORECAST TO MOVE E-NE OVER THE NEXT 24 HOURS AND LOCATE OVER 
THE NE GULF COAST NEAR MOBILE ALABAMA PROVIDING CONTINUED 
PRECIPITATION AND CONVECTION ALONG THE FRONTAL BOUNDARIES TO 
INLAND ACROSS THE GULF COAST E OF 90W. PRIMARILY W-SW UPPER 
LEVEL FLOW IS NOTED ON WATER VAPOR IMAGERY ACROSS THE REMAINDER 
OF THE GULF WITH A SURFACE RIDGE EXTENDING FROM THE MID-ATLC 
STATES ALONG THE EASTERN U.S. SEABOARD TO THE FLORIDA PENINSULA 
PROVIDING GENERALLY FAIR SKIES OVER FLORIDA AND THE FAR EASTERN 
GULF THIS AFTERNOON.

CARIBBEAN SEA...
AN UPPER LEVEL RIDGE WITH AXIS ALONG 75W EXTENDING FROM NORTHERN 
COLOMBIA TO CUBA AND HISPANIOLA COVERS A MAJORITY OF THE 
CARIBBEAN. STRONG SUBSIDENCE IS NOTED ON WATER VAPOR IMAGERY 
WITH ONLY A FEW ISOLATED SHOWERS OCCURRING FROM 15N-18N BETWEEN 
81W-85W DRIVEN PRIMARILY BY SURFACE WIND CONVERGENCE IN THE LOW 
LEVELS. ALSO...SCATTERED SHOWERS AND ISOLATED TSTMS ARE PRESENT 
OVER THE SW CARIBBEAN...PANAMA...AND COSTA RICA S OF 11N. DRY 
W-NW FLOW ALOFT IS OVER PUERTO RICO AND THE LESSER ANTILLES... 
WITH ISOLATED SHOWERS OCCURRING N OF 17N BETWEEN 68W-72W AS WELL 
AS OVER THE SE CARIBBEAN S OF 14N E OF 66W BEING USHERED IN ON 
MODERATE TO FRESH TRADE WINDS.

ATLANTIC OCEAN...
A SURFACE RIDGE EXTENDS FROM THE MID-ATLC STATES ALONG THE U.S. 
EASTERN SEABOARD AND ACROSS THE FAR W ATLC WATER AND FLORIDA 
PENINSULA. MULTILAYERED CLOUDINESS AND ISOLATED SHOWERS SURROUND 
THE SOUTHERN EXTENT OF A STATIONARY FRONT EXTENDING FROM NORTH 
OF THE AREA TO 31N76W. PRECIPITATION CONTINUES TO BE ENHANCED N 
OF 30N W OF 72W BY AN UPPER LEVEL DIFFLUENT ENVIRONMENT EAST OF 
THE APPROACHING SHORTWAVE TROUGH CURRENTLY OVER THE SOUTHERN 
PLAINS AND TROUGHING CURRENTLY OVER EASTERN CANADA. FARTHER TO 
THE SE...A SURFACE TROUGH EXTENDS FROM 32N70W ALONG 27N73W TO 
24N77W. LOW-LEVEL CONVERGENCE NEAR THE SURFACE TROUGH IS 
GENERATING ISOLATED SHOWERS WITHIN 90 NM EITHER SIDE OF THE 
BOUNDARY...INCLUDING THE CENTRAL BAHAMAS. ANOTHER SURFACE TROUGH 
IS ANALYZED FROM 23N63W TO EASTERN HISPANIOLA NEAR 18N69W. 
SCATTERED SHOWERS ARE FROM 20N-23N BETWEEN 59W-70W IN THE 
VICINITY OF THE SURFACE TROUGH. A PAIR OF UPPER LEVEL SHORTWAVE 
TROUGHS ARE EMBEDDED WITHIN MAINLY ZONAL WESTERLY FLOW ACROSS 
THE REMAINDER OF THE ATLC N OF 20N. THE FIRST SHORTWAVE AXIS IS 
LOCATED ALONG 63W N OF 30N AND SUPPORTS A 1013 MB LOW CENTERED 
NEAR 33N68W. A CONVERGENT FRONTAL BOUNDARY EXTENDS E-SE FROM THE 
LOW ALONG 32N62W 28N57W TO 27N53W. SCATTERED SHOWERS AND 
ISOLATED TSTMS ARE WITHIN 120 NM N OF THE BOUNDARY... REMAINING 
LARGELY NORTH OF THE DISCUSSION AREA. THE SECOND UPPER LEVEL 
SHORTWAVE IS ALONG 47W N OF 22N AND SUPPORTS A 1017 MB LOW 
CENTERED NEAR 26N50W. THIS LOW IS NEAR THE TAIL END OF A FRONTAL 
BOUNDARY THAT ENTERS THE DISCUSSION AREA TO THE EAST NEAR 32N19W 
AS A COLD FRONT THAT EXTENDS TO 27N28W AND THEN AS A STATIONARY 
FRONT ALONG 27N/28N TO NORTH OF THE AFOREMENTIONED LOW NEAR 
27N50W. SCATTERED SHOWERS AND ISOLATED TSTMS SURROUND THE LOW 
COVERING THE AREA FROM 22N-32N BETWEEN 42W-52W. SCATTERED 
SHOWERS ARE ALSO OCCURRING WITHIN 90 NM TO 120 NM EITHER SIDE OF 
THE FRONT. 

$$
HUFFMAN