000 AXNT20 KNHC 171733 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST SAT JAN 17 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... THE ITCZ AXIS IS CENTERED ALONG 6N9W 4N15W 2N21W 1N30W CROSSING THE EQUATOR NEAR 41W AND EXTENDING INTO NE BRAZIL NEAR 3S51W. SCATTERED MODERATE CONVECTION IS FROM 3N-7N BETWEEN 10W-13W. NUMEROUS MODERATE CONVECTION IS FROM 1N-4N BETWEEN 14W-29W. SCATTERED MODERATE CONVECTION IS S OF 5N BETWEEN 31W-42W. ...DISCUSSION... THE GULF OF MEXICO... A RELATIVELY COOL AND DRY AIRMASS IS IN PLACE ACROSS THE GULF REGION. THIS AIRMASS IS BEING SUPPORTED BY A 1035 MB SURFACE HIGH CENTERED OVER E ALABAMA NEAR 32N86W...WITH A SURFACE RIDGE EXTENDING SOUTHWESTWARD FROM THIS SURFACE HIGH ACROSS THE GULF REGION. SUBSIDENCE ASSOCIATED WITH THE SURFACE HIGH AND SURFACE RIDGE ARE RESULTING IN GENERALLY FAIR WEATHER ACROSS THE GULF REGION. AT THE SAME TIME...A BROAD UPPER LEVEL TROUGH COVERS THE GULF REGION...WITH NORTHWESTERLY FLOW ALOFT ENHANCING THE SUBSIDENCE ACROSS THE W GULF. DEEP LAYER DRY AIR IS PRESENT ACROSS THE N GULF...WHILE MID/UPPER-LEVEL MOISTURE IS STREAMING EASTWARD ACROSS THE S GULF. THE AFOREMENTIONED SURFACE HIGH AND SURFACE RIDGE ARE FORECAST TO MOVE EASTWARD DURING THE NEXT TWO DAYS...ALLOWING A SURFACE COLD FRONT TO MOVE SOUTHWARD ACROSS THE N AND W GULF FOR SUNDAY THROUGH MONDAY. ADDITIONALLY... STRONG N TO NE SURFACE WINDS ARE BLOWING THROUGH THE ISTHMUS OF TEHUANTEPEC RESULTING IN GALE FORCE WINDS IN THE E PACIFIC REGION. THESE WINDS ARE FORECAST TO HAVE DIMINISHED BELOW GALE FORCE AT 18/1200 UTC. THE CARIBBEAN SEA... ACROSS THE W CARIBBEAN...A DISSIPATING SURFACE STATIONARY FRONT EXTENDS FROM CENTRAL CUBA NEAR 22N78W TO 18N84W TO N OF HONDURAS NEAR 16N86W. RELATIVELY COOLER AND DRIER CONDITIONS ARE PRESENT TO THE NW OF THIS FRONT. LOW LEVEL CONVERGENCE IS SUPPORTING SCATTERED SHOWERS WITHIN 60 NM EITHER SIDE OF THIS FRONT. THIS ACTIVITY IS BEING ENHANCED BY ATMOSPHERIC LIFT IN MOIST SOUTHWESTERLY FLOW ALOFT PRESENT ACROSS THE W CARIBBEAN. ACROSS THE E CARIBBEAN...AN UPPER LEVEL RIDGE IS PRESENT AND IS ASSOCIATED WITH SUBSIDENCE...DEEP LAYER DRY AIR...AND STABLE ATMOSPHERIC CONDITIONS. AS A RESULT...GENERALLY FAIR WEATHER PERSISTS ACROSS THE E CARIBBEAN. HOWEVER...A SURFACE TROUGH ENTERS THE E CARIBBEAN FROM THE SW N ATLC AND EXTENDS FROM PUERTO RICO NEAR 18N66W TO 15N67W TO 12N67W. 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 90 NM EITHER SIDE OF THIS SURFACE TROUGH N OF 14N. THE ATLANTIC OCEAN... STRONG SOUTHWESTERLY FLOW ALOFT IS PRESENT ACROSS THE W ATLC... WITH A DEEP TROUGH OVER THE E CONUS AND W ATLC. THE DEEP TROUGH IS ASSOCIATED WITH A SURFACE STATIONARY FRONT THAT EXTENDS FROM CENTRAL CUBA NEAR 22N78W TO 27N67W TO 32N59W TO NE OF THE DISCUSSION AREA. THIS STATIONARY FRONT IS DISSIPATING E OF 61W AND W OF 76W. THE DEEP TROUGH IS ALSO ASSOCIATED WITH A SURFACE COLD FRONT THAT EXTENDS FROM 31N70W TO 32N67W TO NE OF THE DISCUSSION AREA. LOW LEVEL CONVERGENCE IS SUPPORTING SCATTERED SHOWERS WITHIN 60 NM EITHER SIDE OF THE STATIONARY FRONT AND COLD FRONT. ADDITIONALLY...A STRONG SURFACE COLD FRONT IS FORECAST MOVE OFF THE SE UNITED STATES COAST SUNDAY NIGHT AND MOVE ACROSS PORTIONS OF THE SW N ATLC SUNDAY NIGHT THROUGH TUESDAY...WITH GALE CONDITIONS EXPECTED ACROSS PORTIONS OF THE SW N ATLC ON MONDAY. FARTHER TO THE E...A SURFACE TROUGH EXTENDS FROM 22N65W TO 20N66W TO PUERTO RICO NEAR 18N66W AND EXTENDS INTO THE E CARIBBEAN REGION. SURFACE OBSERVATIONS AND VISIBLE SATELLITE INDICATE THE PRESENCE OF THIS SURFACE TROUGH...AND LOW LEVEL CONVERGENCE IS SUPPORTING SCATTERED SHOWERS WITHIN 90 NM EITHER SIDE OF THIS SURFACE TROUGH. FARTHER TO THE E...AN UPPER HIGH IS CENTERED NEAR 29N39W...WITH A 1035 MB SURFACE HIGH CENTERED NEAR 32N34W. SUBSIDENCE AND STABLE ATMOSPHERIC CONDITIONS ASSOCIATED WITH THE UPPER HIGH AND SURFACE HIGH ARE RESULTING IN GENERALLY FAIR WEATHER ACROSS MUCH OF THE CENTRAL AND E ATLC. ACROSS THE TROPICAL ATLC...WESTERLY FLOW ALOFT IS PRESENT...WITH UPPER LEVEL DIFFLUENCE ENHANCING THE CONVECTION ASSOCIATED WITH THE ITCZ. $$ COHEN