000 AXNT20 KNHC 201734 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST TUE JAN 20 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 1645 UTC. ...THE ITCZ... THE ITCZ AXIS IS CENTERED ALONG 7N9W 4N16W 1N21W CROSSING THE EQUATOR NEAR 23W EXTENDING TO 1S31W AND FURTHER EXTENDING INTO NE BRAZIL NEAR 3S44W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS S OF 5N BETWEEN 7W-18W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS ALSO S OF 2N BETWEEN 20W-24W. SIMILAR CONVECTION IS S OF 5N BETWEEN 32W-43W. SCATTERED MODERATE CONVECTION IS FROM 1N-5N BETWEEN 44W-53W. ...DISCUSSION... GULF OF MEXICO... A DEEP LAYER TROUGH OVER THE E CONUS AND W ATLC EXTENDS INTO THE N GULF REGION...WITH STRONG WESTERLY AND NORTHWESTERLY FLOW ALOFT IN THE BASE OF THIS TROUGH AFFECTING MUCH OF THE GULF REGION. THIS DEEP TROUGH IS SUPPORTING A SURFACE COLD FRONT IN THE GULF. THIS COLD FRONT EXTENDS FROM 23N92W TO 24N84W TO THE S FLORIDA PENINSULA NEAR 26N81W. LOW LEVEL CONVERGENCE IS SUPPORTING ISOLATED SHOWERS WITHIN 30 NM EITHER SIDE OF THIS COLD FRONT. TO THE N OF THIS COLD FRONT...DRIER CONDITIONS ARE PRESENT WITH TEMPERATURES BELOW SEASONAL AVERAGES. SURFACE WINDS ACROSS THE GULF ARE NW TO N AT 15 TO 25 KT. LOW LEVEL INSTABILITY IS BEING GENERATED BY THESE WINDS ADVECTING RELATIVELY COOLER AIR OVER THE WARMER GULF WATERS. THIS IS RESULTING IN SCATTERED TO BROKEN STRATOCUMULUS CLOUDS TO THE N OF THE FRONT. HOWEVER...STABLE ATMOSPHERIC CONDITIONS HIGHER IN THE ATMOSPHERE AND DEEP LAYER DRY AIR ARE GENERALLY INHIBITING DEEP CONVECTION ACROSS MUCH OF THE GULF REGION. ADDITIONALLY... STRONG N SURFACE WINDS ARE FORECAST TO BLOW THROUGH THE ISTHMUS OF TEHUANTEPEC RESULTING IN GALE FORCE WINDS IN THE E PACIFIC REGION BEGINNING AT 21/0600 UTC. CARIBBEAN SEA... THE DEEP LAYER TROUGH OVER THE E CONUS AND W ATLC IS ASSOCIATED WITH A DISSIPATING SURFACE COLD FRONT IN THE NW CARIBBEAN REGION. THIS FRONT EXTENDS FROM E OF BELIZE NEAR 16N88W TO 20N83W TO W CUBA NEAR 22N80W. LOW LEVEL CONVERGENCE IS SUPPORTING ISOLATED SHOWERS WITHIN 30 NM EITHER SIDE OF THIS FRONT. ALSO...A SURFACE TROUGH EXTENDS FROM W OF HAITI NEAR 19N75W TO 14N79W TO 10N80W. SURFACE OBSERVATIONS INDICATE A REGION OF CYCLONIC CURVATURE IN THE SURFACE WIND FIELD IN THE VICINITY OF THIS SURFACE TROUGH...WHERE VISIBLE SATELLITE IMAGERY DEPICTS CYCLONIC MOTION OF LOW LEVEL CLOUDS. LOW LEVEL CONVERGENCE IS SUPPORTING SCATTERED SHOWERS WITHIN 60 NM EITHER SIDE OF THIS SURFACE TROUGH. HOWEVER...DEEP LAYER DRY AIR AND STABLE ATMOSPHERIC CONDITIONS ARE GENERALLY INHIBITING DEEP CONVECTION ACROSS MUCH OF THE CARIBBEAN SEA...WITH A BROAD UPPER LEVEL RIDGE IN PLACE ACROSS THE CARIBBEAN AND AN UPPER HIGH CENTERED NEAR 14N64W. ATLANTIC OCEAN... STRONG SOUTHWESTERLY FLOW ALOFT IS PRESENT ACROSS THE W ATLC... WITH THE DEEP TROUGH OVER THE E CONUS AND W ATLC. THIS DEEP TROUGH IS ASSOCIATED WITH A SURFACE COLD FRONT EXTENDING FROM THE S FLORIDA PENINSULA NEAR 26N81W TO 29N78W TO 32N76W TO N OF THE DISCUSSION AREA...A SURFACE COLD FRONT EXTENDING FROM W CUBA NEAR 22N80W TO 29N71W TO 32N67W TO NE OF THE DISCUSSION AREA THAT IS DISSIPATING W OF 77W...A SURFACE TROUGH EXTENDING FROM 22N70W TO 27N66W TO 31N62W...AND A DISSIPATING SURFACE COLD FRONT THAT EXTENDS FROM 31N62W TO 32N60W TO NE OF THE DISCUSSION AREA. LOW LEVEL CONVERGENCE IS SUPPORTING SCATTERED SHOWERS WITHIN 60 NM EITHER SIDE OF EACH OF THESE SURFACE COLD FRONTS AND SURFACE TROUGH. THIS ACTIVITY IS BEING ENHANCED BY UPPER LEVEL DIVERGENCE ASSOCIATED WITH AN UPPER LEVEL JET MAXIMUM LOCATED NORTH OF THE DISCUSSION AREA. ADDITIONALLY...GALE FORCE WINDS ARE OCCURRING ACROSS PORTIONS OF THE SW N ATLC N OF 27N. FARTHER TO THE E...A 1035 MB SURFACE HIGH IS CENTERED NEAR 35N30W. SUBSIDENCE AND STABLE ATMOSPHERIC CONDITIONS ASSOCIATED WITH THIS SURFACE HIGH ARE RESULTING IN GENERALLY FAIR WEATHER ACROSS MUCH OF THE CENTRAL AND E ATLC. HOWEVER...AN UPPER LOW IS CENTERED NEAR 16N48W. ATMOSPHERIC INSTABILITY ASSOCIATED WITH THIS UPPER LOW IS RESULTING IN ISOLATED SHOWERS FROM 15N-19N BETWEEN 45W-49W. ACROSS THE TROPICAL ATLC...WESTERLY FLOW ALOFT IS PRESENT...WITH UPPER LEVEL DIVERGENCE ENHANCING THE CONVECTION ASSOCIATED WITH THE ITCZ. $$ COHEN