000 AXNT20 KNHC 121115 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 705 AM EST MON JAN 12 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1045 UTC. ...THE ITCZ... ITCZ IS CENTERED ALONG 6N9W 2N21W 2N31W 2N40W AND INTO NE BRAZIL NEAR 1S49W. SCATTERED MODERATE CONVECTION IS FROM 1N-5N BETWEEN 21W-31W. SCATTERED MODERATE CONVECTION IS ALSO WITHIN 120 NM EITHER SIDE OF THE ITCZ AXIS BETWEEN 32W-39W. ...DISCUSSION... GULF OF MEXICO... SOUTHWESTERLY FLOW ALOFT CONTINUES TO INCREASE ACROSS THE GULF REGION AS A DEEP TROUGH OVER THE E CONUS MOVES EASTWARD. A SURFACE FRONT ASSOCIATED WITH THIS DEEP TROUGH EXTENDS FROM THE N FLORIDA PENINSULA NEAR 29N82W TO 24N88W TO THE BAY OF CAMPECHE NEAR 21N93W TO S MEXICO NEAR 18N92W. THIS FRONT IS MOVING SOUTHEASTWARD AS A COLD FRONT ALONG AND E OF 91W AND IS STATIONARY W OF 91W. LOW LEVEL CONVERGENCE IS SUPPORTING SCATTERED SHOWERS AND THUNDERSTORMS ALONG AND WITHIN 60 NM SE OF THIS FRONT. THIS ACTIVITY IS BEING ENHANCED IN THE SW QUADRANT OF AN UPPER LEVEL JET MAXIMUM LOCATED OVER THE SE CONUS. THIS FRONT IS FORECAST TO BECOME ENTIRELY STATIONARY OVER THE GULF TODAY AND THEN BECOME REINFORCED TONIGHT. THIS FRONT IS THEN FORECAST TO MOVE SOUTHEASTWARD ACROSS THE REMAINDER OF THE GULF ON TUESDAY AS A COLD FRONT. INCREASED NORTHERLY WINDS...AS WELL AS RELATIVELY COOLER AND DRIER CONDITIONS...ARE PRESENT TO THE NW OF THIS FRONT. ALSO...A GALE WARNING IS IN EFFECT FOR PORTIONS OF THE SW GULF. AHEAD OF THE FRONT...INCLUDING PORTIONS OF THE SE GULF...THE RETURN FLOW AROUND A 1028 MB SURFACE HIGH OVER THE CENTRAL ATLC NEAR 36N42W IS RESULTING IN E TO SE SURFACE WINDS OF 10 KT. ADDITIONALLY...STRONG N TO NE SURFACE WINDS ARE BLOWING THROUGH THE ISTHMUS OF TEHUANTEPEC RESULTING IN GALE FORCE WINDS IN THE E PACIFIC REGION. CARIBBEAN SEA... AN UPPER RIDGE IS PRESENT ACROSS THE CARIBBEAN SEA...WITH THE UPPER RIDGE AXIS EXTENDING FROM N VENEZUELA NEAR 10N70W TO 16N76W TO 21N82W. SUBSIDENCE AND STABLE ATMOSPHERIC CONDITIONS ASSOCIATED WITH THIS UPPER RIDGE ARE RESULTING IN GENERALLY FAIR WEATHER ACROSS MUCH OF THE CARIBBEAN SEA. HOWEVER...ACROSS THE W CARIBBEAN...DEEP MOISTURE IS BEING TRANSPORTED NORTHWARD TO THE W OF THE UPPER RIDGE AXIS...WHICH IS RESULTING IN ISOLATED SHOWERS FROM 15N-21N W OF 81W. MODERATE TO STRONG EASTERLY TRADE WINDS ARE PRESENT ACROSS MUCH OF THE CARIBBEAN SEA. THESE TRADE WINDS ARE FORECAST TO CONTINUE THROUGH THE NEXT FEW DAYS AS THE 1028 MB SURFACE HIGH IN THE CENTRAL ATLC NEAR 36N42W MOVES EAST-NORTHEASTWARD. A COLD FRONT IS FORECAST TO ENTER THE NW CARIBBEAN SEA ON WEDNESDAY AND REACH A LINE FROM CENTRAL CUBA TO HONDURAS ON WEDNESDAY BEFORE IT STALLS THROUGH FRIDAY. ATLANTIC OCEAN... SOUTHWESTERLY FLOW ALOFT CONTINUES TO INCREASE ACROSS THE W ATLC AS A DEEP TROUGH OVER THE E CONUS MOVES EASTWARD. A SURFACE COLD FRONT IN THE W ATLC ASSOCIATED WITH THIS DEEP TROUGH EXTENDS FROM NE OF THE DISCUSSION AREA TO 32N76W TO 30N79W TO THE N FLORIDA PENINSULA NEAR 29N82W. LOW LEVEL CONVERGENCE IS SUPPORTING SCATTERED SHOWERS ALONG AND WITHIN 60 NM E OF THE COLD FRONT. FARTHER TO THE E...DEEP LAYER DRY AIR AND SUBSIDENCE ARE RESULTING IN GENERALLY FAIR WEATHER ACROSS MUCH OF THE SW AND CENTRAL ATLC. THIS SUBSIDENCE IS BEING ENHANCED AROUND THE 1028 MB SURFACE HIGH NEAR 36N42W. THE W ATLC COLD FRONT IS FORECAST TO MERGE WITH A REINFORCING SURFACE COLD FRONT ON TUESDAY. SW WINDS TO GALE FORCE ARE FORECAST FOR LOCATIONS N OF 29N WITHIN 360 NM E OF THE COLD FRONT FOR TUESDAY THROUGH EARLY WEDNESDAY. FARTHER TO THE E...AN UPPER TROUGH IS PRESENT WITH AN AXIS EXTENDING FROM 16N51W TO 27N42W TO 32N38W TO NE OF THE DISCUSSION AREA. THIS UPPER TROUGH IS ASSOCIATED WITH A SURFACE TROUGH THAT EXTENDS FROM 27N48W TO 30N40W TO 32N36W TO NE OF THE DISCUSSION AREA. LOW LEVEL CONVERGENCE IS SUPPORTING ISOLATED SHOWERS WITHIN 60 NM EITHER SIDE OF THIS SURFACE TROUGH. ALSO...ATMOSPHERIC INSTABILITY AND UPPER LEVEL DIFFLUENCE ASSOCIATED WITH THE UPPER TROUGH ARE SUPPORTING SCATTERED SHOWERS FROM 21N-25N BETWEEN 24W-30W AND FROM 28N-31N BETWEEN 26W-30W. ACROSS THE TROPICAL ATLC...AN UPPER RIDGE IS PRESENT WITH AN AXIS EXTENDING FROM 5N7W TO 3N20W TO 1N32W. UPPER LEVEL DIVERGENCE NEAR THIS UPPER RIDGE IS ENHANCING THE CONVECTION ASSOCIATED WITH THE ITCZ. $$ COHEN