000
AXNT20 KNHC 291707
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL  
105 PM EST TUE DEC 29 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 THE 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY 
THROUGH 1715 UTC.

...THE ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 8N13W 5N20W 2N40W EQ48W. 
SCATTERED MODERATE CONVECTION IS N OF THE COAST OF BRAZIL FROM 
1N-5N BETWEEN 30W-43W. 

...DISCUSSION...

THE GULF OF MEXICO...
A SURFACE RIDGE IS OVER THE GULF OF MEXICO PRODUCING 15-20 KT 
NORTHERLY WINDS TOGETHER WITH A GOOD AMOUNT OF COLD AIR 
ADVECTION OVER MOST OF THE AREA. BROKEN TO OVERCAST LOW CLOUDS 
ARE OVER THE GULF W OF 84W. A SURFACE TROUGH IS OVER THE W GULF 
FROM BROWNSVILLE TEXAS TO VERACRUZ MEXICO PRODUCING RAIN AND 
SHOWERS OVER THE W GULF W OF 95W. IN THE UPPER LEVELS...A RIDGE 
WITH AXIS ALONG 80W IS PRODUCING SW UPPER LEVEL FLOW OVER THE 
GULF. UPPER LEVEL MOISTURE WITH BROKEN HIGH CLOUDS ARE OVER 
TEXAS AND THE W GULF W OF 95W. STRONG SUBSIDENCE IS OVER THE 
REMAINDER OF THE GULF. 70-90 KT 25O MB WINDS ARE NOTED OVER THE 
N GULF N OF 26N. EXPECT IN 24 HOURS...FOR A SURFACE LOW TO 
DEVELOP OVER THE NW GULF WITH CONVECTION.  

THE CARIBBEAN SEA...
MODERATE TO FRESH TRADEWINDS ARE OVER THE CARIBBEAN SEA AND 
CENTRAL AMERICA. BROKEN LOW CLOUDS WITH ISOLATED SHOWERS ARE 
OVER THE W CARIBBEAN AND CENTRAL AMERICA W OF 80W. FURTHER E... 
A BAND OF SHOWERS IS OVER HISPANIOLA. IN THE UPPER LEVELS...AN 
UPPER LEVEL HIGH IS CENTERED OVER N COLOMBIA NEAR 12N72W. STRONG 
SUBSIDENCE IS OVER THE ENTIRE CARIBBEAN AND CENTRAL AMERICA 
SUPPRESSING DEEP CONVECTION. EXPECT OVER THE NEXT 24 HOURS FOR 
SHOWERS TO BE OVER THE NW CARIBBEAN AND YUCATAN PENINSULA.

THE ATLANTIC OCEAN...
THE TAIL END OF A DISSIPATING COLD FRONT ENTERS THE W ATLANTIC 
NEAR 32N59W AND EXTENDS S TO HISPANIOLA NEAR 21N70W. A 
REINFORCING COLD FRONT IS JUST W OF THE DISSIPATING COLD FRONT 
ALONG 32N61W 26N67W 22N77W. BROKEN COLD AIR STRATOCUMULUS CLOUDS 
ARE W OF THIS FRONT TO 80W N OF 25N. SCATTERED SHOWERS ARE 
WITHIN 60 NM OF BOTH FRONTS. A TIGHT SURFACE PRESSURE GRADIENT 
OVER THE W ATLANTIC NEAR THE COLD FRONTS IS PRODUCING GALE 
FORCE WINDS N OF 28N BETWEEN 58W-63W. IN THE UPPER LEVELS...A 
RIDGE IS OVER THE W ATLANTIC W OF 50W. AN UPPER LEVEL TROUGH IS 
FURTHER E OVER THE CENTRAL ATLANTIC BETWEEN 20W-50W. AN UPPER 
LEVEL LOW IS CENTERED OVER THE TROPICAL E ATLANTIC 3N15W.  
EXPECT OVER THE NEXT 24 HOURS...FOR THE TWO FRONTS TO MERGE AND 
MOVE E TO THE CENTRAL ATLANTIC WITH CONVECTION.  

FOR ADDITIONAL INFORMATION PLEASE VISIT 
HTTP://WWW.HURRICANES.GOV/MARINE.

$$

FORMOSA