000
AXNT20 KNHC 031732
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST SAT JAN 03 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.

...THE ITCZ...

ITCZ IS CENTERED ALONG 7N11W 4N21W 3N32W 3N43W 2N52W. SCATTERED 
MODERATE CONVECTION IS FROM 3N-7N BETWEEN 6W-23W. SCATTERED 
MODERATE/ISOLATED STRONG CONVECTION IS S OF 2N BETWEEN THE PRIME 
MERIDIAN AND 18W. 

...DISCUSSION...

GULF OF MEXICO...
STRONG WESTERLY FLOW ALOFT COVERS MUCH OF THE GULF REGION...WITH 
MID/UPPER-LEVEL MOISTURE STREAMING ACROSS THE N GULF. A 120-KT 
UPPER LEVEL JET MAXIMUM IS CENTERED OVER N MEXICO AND S TEXAS. 
UPPER LEVEL DIVERGENCE IN THE NE QUADRANT OF THIS JET MAXIMUM IS 
COMBINING WITH MOISTURE ACROSS THE N GULF TO SUPPORT SCATTERED 
SHOWERS AND THUNDERSTORMS N OF 26N BETWEEN 89W-95W. AT THE SAME 
TIME...THE RETURN FLOW AROUND A SURFACE HIGH IN THE W ATLC NEAR 
30N52W IS BRINGING SE TO S SURFACE WINDS OF 10 TO 20 KT ACROSS 
THE GULF REGION. THESE SURFACE WINDS CONTINUE TO ADVECT LOW 
LEVEL MOISTURE ACROSS THE GULF REGION...FURTHER ENHANCING THE 
AFOREMENTIONED SHOWER AND THUNDERSTORM ACTIVITY. SUBSIDENCE 
ASSOCIATED WITH A BROAD UPPER LEVEL RIDGE OVER THE S GULF IS 
INHIBITING DEEP CONVECTION ACROSS THE S GULF. FARTHER TO THE 
N...A SURFACE FRONT IS DRAPED ACROSS THE CENTRAL PLAINS AND 
EXTENDS ACROSS THE CENTRAL ROCKY MOUNTAIN REGION OF THE CONUS. 
THIS FRONT IS FORECAST TO ENTER THE NW GULF LATE SUNDAY AS A 
COLD FRONT.

CARIBBEAN SEA...
SW TO W UPPER LEVEL FLOW IN ASSOCIATION WITH A BROAD UPPER LEVEL 
RIDGE COVERS MUCH OF THE CARIBBEAN SEA. THIS BROAD UPPER RIDGE 
IS ANCHORED BY AN UPPER HIGH IN N GUYANA NEAR 7N59W. 
SUBSIDENCE...DEEP LAYER DRY AIR...AND STABLE ATMOSPHERIC 
CONDITIONS ASSOCIATED WITH THIS UPPER HIGH AND UPPER RIDGE ARE 
RESULTING IN FAIR WEATHER CONDITIONS ACROSS MUCH OF THE W AND 
CENTRAL CARIBBEAN SEA. GREATER MID/UPPER-LEVEL MOISTURE ACROSS 
THE E CARIBBEAN SEA IS SUPPORTING ISOLATED SHOWERS FROM 12N-17N 
BETWEEN 62W-70W. ACROSS MUCH OF THE CARIBBEAN SEA...NE TO E 
SURFACE WINDS OF 15 TO 25 KT...EXCEPT TO 30 KT ALONG THE COAST 
OF COLOMBIA...ARE PRESENT.

ATLANTIC...
ACROSS THE W ATLC...STRONG SW TO W FLOW ALOFT IS PRESENT IN THE 
BASE OF AN UPPER TROUGH. DEEP CONVECTION IS BEING INHIBITED 
ACROSS THE W ATLC BY DEEP LAYER DRY AIR...AND SUBSIDENCE 
ASSOCIATED WITH A 1023 MB SURFACE HIGH NEAR 30N52W. DURING THE 
NEXT DAY...A 1022 MB SURFACE HIGH IS FORECAST TO FORM NEAR 
29N70W. FARTHER TO THE E...A SURFACE STATIONARY FRONT EXTENDS 
FROM 25N77W TO 25N61W TO 28N48W...AND A SURFACE COLD FRONT 
EXTENDS FROM 28N48W TO 29N44W TO 32N40W TO NE OF THE DISCUSSION 
AREA. LOW LEVEL CONVERGENCE IS SUPPORTING SCATTERED SHOWERS 
WITHIN 90 NM EITHER SIDE OF THESE FRONTS. SUBSIDENCE ASSOCIATED 
WITH AN UPPER RIDGE N OF 21N BETWEEN 35W-50W AND A SURFACE RIDGE 
EXTENDING FROM A 1028 MB SURFACE HIGH NEAR 34N24W TO NEAR 13N42W 
IS RESULTING IN GENERALLY FAIR WEATHER CONDITIONS ACROSS MUCH OF 
THE E ATLC. FARTHER TO THE E...AN UPPER TROUGH IS N OF 22N E OF 
28W...THOUGH DEEP LAYER DRY AIR IS INHIBITING DEEP CONVECTION 
NEAR THIS FEATURE. ACROSS THE TROPICAL ATLC...GENERALLY WESTERLY 
FLOW ALOFT IS PRESENT...WITH UPPER LEVEL DIFFLUENCE ENHANCING 
THE CONVECTION IN THE VICINITY OF THE ITCZ.

$$
COHEN