000 AXNT20 KNHC 240515 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 105 AM EST SAT FEB 24 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0415 UTC. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 9N12W 4N19W 2N20W CROSSING THE EQUATOR NEAR 36W TO INLAND OVER SOUTH AMERICA NEAR 2S48W. SCATTERED/NUMEROUS STRONG CONVECTION IS FROM THE EQUATOR TO 3N BETWEEN 7W-15W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 150 NM ALONG THE COAST OF SOUTH AMERICA FROM 47W-54W. SCATTERED THUNDERSTORMS ARE FROM THE EQUATOR TO 3N BETWEEN 35W-42W. ...DISCUSSION... GULF OF MEXICO... STRONG UPPER LEVEL RIDGE REMAINS OVER THE GULF ALONG 87W CONTINUING FAIR CONDITIONS OVER MUCH OF THE GULF TONIGHT. MID/UPPER LEVEL CLOUDS CONTINUE TO SPREAD OVER THE NW GULF BEING ADVECTED ACROSS MEXICO AND TEXAS IN ADVANCE OF THE DEVELOPING STORM SYSTEM OVER THE CENTRAL PLAINS. A WARM FRONT IS ALONG THE LEADING EDGE OF THIS AIR MASS AND EXTENDS BETWEEN CORPUS CHRISTI AND GALVESTON TEXAS SE TO 25N90W. OTHERWISE...HIGH PRESSURE IS CENTERED ALONG THE SOUTH CAROLINA COAST WITH THE TAIL END OF AN ATLC COLD FRONT SWEEPING ACROSS S JUST OFF THE FLORIDA E COAST USHERING IN SLIGHTLY DRIER AIR. ANOTHER COLD FRONT WILL MOVE INTO TEXAS LATER TONIGHT INTO THE DAY SAT THEN WILL MOVE OFF THE COAST INTO THE NW GULF LAT IN THE DAY INTO SUN MORNING CLEARING THE GULF EARLY NEXT WEEK. SCATTERED SHOWERS/THUNDERSTORMS WILL DEVELOP OVER THE FAR N GULF AHEAD OF THE FRONT MAINLY SAT NIGHT THEN SHIFT TO EAST ACROSS THE GULF FOR THE REMAINDER OF THE WEEKEND. CARIBBEAN... MID/UPPER LEVEL HIGH IS CENTERED ALONG THE COAST OF NICARAGUA WITH THE AXIS EXTENDING EASTWARD TO THE SOUTHERN MOST WINDWARD ISLANDS. AS A RESULT...THIS IS PRODUCING STRONG SUBSIDENCE AND DRY UPPER AIR OVER THE REGION KEEPING ANY SHOWER ACTIVITY FAIRLY SUPPRESSED. A BAND OF POSSIBLE SHOWERS...LIKELY A REMNANT OF AN OLD FRONTAL BOUNDARY...DOES EXTEND FROM OVER HISPANIOLA/ WINDWARD PASSAGE TO JAMAICA THEN TO THE NE COAST OF NICARAGUA. ATLANTIC... A LARGE AND COMPLEX POLAR VORTEX IS MOVING E OF THE CANADIAN MARITIMES WITH BROAD CYCLONIC FLOW SWEEPING ACROSS THE W/CENTRAL ATLC. AN 974 MB LOW WITH HURRICANE FORCE WINDS IS CENTERED WELL N OF THE AREA AND IS SHOWING SIGNS OF WEAKENING ALTHOUGH ITS ASSOCIATED COLD FRONT REMAINS STRONG WITH WINDS IN THE REGION BELOW GALE FORCE. THE COLD FRONT ENTERS THE REGION NEAR 32N56W EXTENDING SW ALONG 26N65W THEN W TO THE NORTHERN BAHAMAS AND THE S FLORIDA COAST NEAR 25N80W. THE PRE-FRONTAL TROUGH IS ABOUT 250 NM SE OF THE FRONT...EXTENDING FROM 30N52W TO 22N63W. WHILE THE FRONT ITSELF IS RATHER DRY...THERE ARE SCATTERED SHOWERS/ ISOLATED THUNDERSTORMS WITHIN UP TO 120 NM E OF THE TROUGH N OF 23N AND WITHIN 120 NM W OF THE TROUGH N OF 27N. THE FRONT IS EXPECTED TO STALL AS IT REACHES THE N CARIBBEAN BY SUN MORNING WITH THE MID-LATITUDE PORTION CONTINUING TO THE E AND PRODUCING A BAND OF SHOWERS/THUNDERSTORMS. ELSEWHERE...THE SURFACE LOW LOCATED JUST OFF THE N COAST OF HISPANIOLA HAS LOST ITS IDENTITY...AND IS NOW A SURFACE TROUGH EXTENDING FROM 23N68W TO 20N71W WITH ISOLATED SHOWERS WITHIN 75 NM EITHER SIDE OF THE TROUGH. THIS FEATURES IS EXPECTED TO DISSIPATE OVER THE NEXT 12 TO 24 HRS. A STRONG 1029 MB HIGH IS CENTERED W OF THE CANARY ISLANDS NEAR 29N25W WITH THE SURFACE RIDGE EXTENDING SW TO 23N50W. THIS STRONG HIGH CONTINUES TO SUPPRESS THE ITCZ AXIS WELL TO THE SOUTH. THE UPPER LEVEL MID-LATITUDE FLOW IS CHARACTERIZED BY A LOW AMPLITUDE RIDGE ALONG 30W. BENEATH THAT FLOW...A CUT-OFF MID/UPPER LEVEL TROUGH EXTENDS FROM 21N25W SW TO 14N34W WITH ITS OWN PATCH OF MODERATE/STRONG SUBSIDENCE WITHIN A 200/250 NM RADIUS. $$ WALLACE