000 AXNT20 KNHC 181027 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT TUE MAR 18 2008 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0945 UTC. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 6N8W 3N14W 1N24W CROSSING THE EQUATOR NEAR 31W TO 4S40W. SCATTERED MODERATE/STRONG CONVECTION IS N OF 2N TO INLAND OVER SW AFRICA BETWEEN 2W-5W. CLUSTERS OF SIMILAR CONVECTION ARE FROM 5N TO S OF THE EQUATOR BETWEEN 18W-26W. ...DISCUSSION... GULF OF MEXICO... AN UPPER LOW IS OVER W TEXAS WITH A FRONTAL SYSTEM MOVING ACROSS CENTRAL TEXAS. THIS FRONT IS EXPECTED TO MOVE INTO THE NW GULF LATE TONIGHT. A SURFACE RIDGE ANCHORED OVER E VIRGINIA COVERS THE E GULF INTO THE W ATLC AND IS PRODUCING A TIGHT PRESSURE GRADIENT OVER THE GULF OF MEXICO WITH GALE FORCE WINDS OVER THE W GULF. HEAVY SHOWERS/SEVERE THUNDERSTORMS REMAIN INLAND OVER TEXAS MOVING NNE TO THE CENTRAL MISSISSIPPI VALLEY. THIS ACTIVITY IS EXPECTED TO ENTER THE GULF LATER TODAY PRECEDING THE FRONT. ABROAD HIGHLY AMPLIFIED UPPER RIDGE COVERS THE GULF AND THE E U.S. INTO THE W ATLC WITH THE AXIS ALONG 86W. CURRENTLY LOW CLOUDS ARE BEING BANKED ALONG THE N GULF COAST BETWEEN ALABAMA AND LOUISIANA IN RESPONSE TO THE RETURN FLOW AROUND THE SURFACE RIDGE. CARIBBEAN SEA... UPPER TROUGH OVER THE CENTRAL ATLC DIPS INTO THE NE CARIBBEAN N OF 17N W OF 75W WHILE THE REMAINDER OF THE CARIBBEAN IS UNDER A BROAD UPPER RIDGE. STRONG SUBSIDENCE AND DRY STABLE AIR IS CURRENTLY OVER THE REGION. HOWEVER...A COLD FRONT EXTENDS FROM THE CENTRAL ATLC TO OVER HISPANIOLA AND IS BEGINNING TO WEAKEN OVER THE CARIBBEAN ISLANDS. MODERATE/STRONG EASTERLY TRADE WINDS REMAIN OVER THE AREA USHERING IN SOME SCATTERED PATCHES OF LOW CLOUDS WITH POSSIBLE ISOLATED SHOWERS MAINLY S OF 15N. THE FRONT IS EXPECTED TO CONTINUE TO WEAKEN AND LITTLE OTHER CHANGE IS EXPECT ACROSS THE REMAINDER OF THE CARIBBEAN THROUGH FRI. ATLANTIC OCEAN... HIGH AMPLITUDE UPPER RIDGE COVERS THE W ATLC W OF 70W ACROSS FLORIDA INTO THE GULF OF MEXICO. A SURFACE RIDGE ANCHORED OVER E VIRGINIA COVERS THE W ATLC W OF 65W INTO THE GULF OF MEXICO. A STRONG STORM SYSTEM IS OVER THE N/CENTRAL ATLC WITH THE UPPER TROUGH OVER THE AREA N OF 17N FROM 45-70W AND THE ASSOCIATED COLD FRONT ENTERING THE REGION NEAR 32N46W ALONG 24N53W OVER HISPANIOLA NEAR 19N70W DISSIPATING ALONG THE S COAST OF CUBA. THIS FRONT HAS SLOWED ITS EASTWARD PROGRESSION AND IS NO LONGER AS WELL DEFINED AS PREVIOUSLY. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 75 NM E OF THE FRONT AND GALE FORCE WINDS ARE BOTH E AND W OF THE FRONT...SEE MIAHSFAT2 FOR MORE DETAILS. STRONG SUBSIDENCE AND DRY STABLE AIR COVER MOST OF THE REGION THUS LIMITING ANY FURTHER AREA OF SHOWERS. BROAD UPPER TROUGH COVERS THE E ATLC N OF 27N E OF 35W. SURFACE RIDGE COVERS THE E ATLC E OF 40W AND ANCHORED BY A1025 MB HIGH JUST SW OF THE AZORES. $$ WALLACE