000
AXNT20 KNHC 042353
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST THU JAN 04 2007

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL 
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN 
SECTIONS OF SOUTH AMERICA...AND THE 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2315 UTC.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 1N AT THE PRIME MERIDIAN TO 1S15W 
4N30W 3N40W CROSSING THE EQUATOR AT 50W. WIDELY SCATTERED 
MODERATE CONVECTION IS WITHIN AROUND 120 NM N OF THE AXIS 
BETWEEN 17W-31W.

...DISCUSSION...
GULF OF MEXICO...
AS OF 2100 UTC...A 1007 MB SURFACE LOW IS OVER LOUISIANA. A COLD 
FRONT EXTENDS FROM THIS LOW ACROSS THE GULF ALONG 25N93W TO THE 
MEXICAN COAST NEAR TAMPICO. DOPPLER RADAR SHOWS NUMEROUS SHOWERS 
AND TSTMS OVER LOUISIANA/MISSISSIPPI AND THE REGIONAL COASTAL 
WATERS. A 100-140 NM WIDE BAND OF SHOWERS WITH EMBEDDED TSTMS IS 
RELATED TO THE FRONTAL BOUNDARY. THE STRONGEST ACTIVITY EXISTS N 
OF 27N BETWEEN 89W-92W. A VIGOROUS MID/UPPER LEVEL TROUGH OVER N 
CENTRAL TEXAS AND NE MEXICO SUPPORTS THE SURFACE LOW/FRONT. A 
WARM FRONT STRETCHES EWD FROM THE LOW ALONG THE SE U.S. THE COLD 
FRONT WILL DISSIPATE LATE FRI AND THEN THE ATLC RIDGE WILL BUILD 
ACROSS THE AREA. SLY RETURN FLOW OF 15 TO 20 KT WILL DOMINATE 
THE GULF AHEAD OF THE NEXT COLD FRONT THAT IS EXPECTED TO 
APPROACH THE TEXAS COAST LATE SATURDAY. 

CARIBBEAN SEA...
A GALE WARNING REMAINS IN EFFECT FROM 11N TO 14N BETWEEN 74W AND 
77W. EARLIER QUIKSCAT PASS SHOWED E WIND OF 35 KT ACROSS THE 
AREA. BRISK 20-25 KT TRADE WINDS CONTINUE TO BLOW ACROSS THE 
REMAINDER OF THE BASIN GENERATING HAZARDOUS MARINE CONDITIONS. 
BESIDES FOR THE STRONG TRADES...THE WEATHER IS FAIRLY TRANQUIL 
AS ABUNDANT VERY DRY MID/UPPER LEVEL AIR DOMINATES THE REGION. 
THIS DRY AIR IS BEING SUPPORTED BY AN UPPER HIGH CENTERED OVER 
HONDURAS AND TROUGHING EXTENDING ACROSS MUCH OF THE ERN CARIB. 
PATCHES OF LOW LEVEL MOISTURE WITH EMBEDDED SHOWERS ARE BEING 
CARRIED BY THE TRADE WINDS ACROSS THE REGION...AFFECTING THE 
LESSER/GREATER ANTILLES FROM TIME TO TIME AS WELL AS THE 
CARIBBEAN PLAINS OF NICARAGUA AND COSTA RICA. THE ATLC HIGH PRES 
RIDGE N OF AREA WILL CONTINUE TO PRODUCE STRONG E WIND THROUGH 
SUNDAY.

ATLANTIC OCEAN...
THE UPPER HIGH LOCATED OVER HONDURAS EXTENDS A BROAD RIDGE OVER 
THE SE U.S....INCLUDING THE FLORIDA PENINSULA AND THE W ATLC. 
ABUNDANT UPPER LEVEL MOISTURE IS BEING ADVECTED INTO THE AREA W 
OF 70W N OF 24N...DRIVEN BY WLY UPPER LEVEL FLOW ON THE N 
PERIPHERY OF THIS RIDGE. E OF THE RIDGE...A BROAD WEAK UPPER 
LEVEL TROUGH COVERS THE AREA ROUGHLY BETWEEN 50W AND 70W. THE 
ATTENDANT SFC COLD FRONT ENTERS THE AREA NEAR 31N47W AND EXTENDS 
MAINLY WWD ALONG 28N55W 29N64W WHERE IT BECOMES STATIONARY.  A 
WEAK SFC TROUGH LOCATED SE OF THE COLD FRONT IS ANALYZED FROM 
30N42W TO 23N50W. A SWATH OF MOISTURE WITH SCATTERED TO NUMEROUS 
SHOWERS IS BETWEEN THE COLD FRONT AND THE SFC TROUGH. AN UPPER 
LOW IS NEAR 27N34W. A WIDE AREA OF BROKEN CLOUDINESS AND LIKELY 
SCATTERED SHOWERS LIE TO THE E OF THE UPPER LOW...N OF 20N 
BETWEEN 20W-35W. THIS ACTIVITY IS GENERATING BY STRONG S-SWLY 
UPPER LEVEL WINDS. AT THE SURFACE...TWO HIGH PRES CENTERS 
DOMINATE THE OCEAN. ONE IS A 1030 MB HIGH LOCATED NEAR 35N59W. 
THE OTHER ONE IS A 1035 MB HIGH SITUATED JUST NORTH OF THE 
MADEIRA ISLANDS. THESE SYSTEMS ARE PRODUCING MODERATE TO STRONG 
ELY WINDS ACROSS MUCH OF THE AREA...INCLUDING THE DEEP TROPICS.  

$$
GR