000 AXNT20 KNHC 160545 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT MON APR 16 2012 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...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0515 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL ATLC NEAR 6N10W 3N13W 2N22W WHERE THE ITCZ AXIS CONTINUES ALONG 1N27W THEN S OF THE EQUATOR NEAR 31W. SCATTERED CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION ARE FROM 4N TO THE EQUATOR E OF 22W TO ACROSS THE PRIME MERIDIAN. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE S OF 9N TO INLAND OVER SOUTH AMERICA BETWEEN 50W-55W. ...DISCUSSION... GULF OF MEXICO... BROAD UPPER RIDGE DOMINATES THE GULF N OF 24N ANCHORED OVER NE FLORIDA AND EXTENDS INTO THE W ATLC. THIS UPPER RIDGE IS BEING AMPLIFIED N BY A STRONG UPPER TROUGH OVER THE CENTRAL PLAIN STATES. THIS UPPER TROUGH IS SUPPORTING A NOW STATIONARY FRONT INLAND OVER TEXAS GENERATING SCATTERED TO HEAVY SHOWERS WITH SCATTERED TO NUMEROUS THUNDERSTORMS INLAND OVER TEXAS THROUGH NE LOUISIANA TO OVER THE MISSISSIPPI VALLEY. THESE SHOWERS/ THUNDERSTORMS ARE MOVING INTO THE GULF ALONG THE IMMEDIATE TEXAS COASTLINE. A SECOND UPPER RIDGE EXTENDS FROM THE E PACIFIC REGION ACROSS S MEXICO AND THE BAY OF CAMPECHE TO 24N94W. A SURFACE RIDGE ANCHORED IN THE W ATLC EXTENDS ALONG THE N GULF COAST TO SE LOUISIANA GIVING THE GULF SOUTHERLY RETURN FLOW N OF 25N. STRONG SUBSIDENCE AND DRY STABLE AIR DOMINATES THE GULF WATERS. HOWEVER THE SOUTHERLY RETURN FLOW IS USHERING IN SOME LOW LEVEL MOISTURE AND SUBSEQUENT ISOLATED SHOWERS MAINLY DOTTING THE E GULF E OF 89W LEAVING THE REMAINDER OF THE GULF WITH CLEAR SKIES TONIGHT. THE SOUTHERLY RETURN FLOW WILL DIMINISH FROM THE W TO E ON MON AS THE NOW STATIONARY FRONT BECOMES A COLD AND WILL MOVE E AGAIN ON TUE REACHING FROM THE FLORIDA PANHANDLE TO THE CENTRAL WATERS TUE NIGHT THEN DRIFTING E ACROSS THE NE GULF WED AND WED NIGHT. REMNANTS OF THE FRONT WILL DISSIPATE OVER N FLORIDA ON THU AS AN E TO W RIDGE DEVELOPS ACROSS THE NORTHERN COASTAL PLAINS. THE RIDGE WILL SHIFT S TO ALONG 28N ON FRI. CARIBBEAN SEA... NEAR ZONAL WESTERLY FLOW ALOFT DOMINATES THE ENTIRE CARIBBEAN. A RELATIVELY TIGHT PRESSURE GRADIENT AS THE SURFACE RIDGE OVER THE W ATLC EXTENDS S TO ACROSS THE GREATER ANTILLES OVER THE N CARIBBEAN AND IS GENERATING FRESH TO MODERATE EASTERLY TRADE WINDS ACROSS THE BASIN. MODERATE TO STRONG SUBSIDENCE AND DRY AIR ALOFT COVERS THE CARIBBEAN. A SHEAR AXIS EXTENDS FROM CENTRAL ATLC FRONT OVER GUADALOUPE IN THE LESSER ANTILLES TO NEAR 13N73W. THIS SHEAR AXIS IS PROVING LIFT FOR SOME LOW LEVEL MOISTURE THAT REMAINS ACROSS THE E CARIBBEAN TO GENERATE SCATTERED SHOWERS WITHIN 120 NM N AND 90 NM S OF THE SHEAR AXIS. A SECOND BAND OF LOW LEVEL MOISTURE WITH SCATTERED SHOWERS EXTENDS WITHIN 75 NM OF A LINE FROM OVER HISPANIOLA ALONG 18N74W 17N80W TO 20N86W INCLUDING JAMAICA. THIS IS LEAVING THE REMAINDER OF THE CARIBBEAN WITH FAIR WEATHER TONIGHT. THE SHEAR AXIS WILL CONTINUE TO WEAKEN AS IT MOVES E INTO THE TROPICAL ATLC WATERS THROUGH WED. THE W ATLC SURFACE RIDGE WILL GRADUALLY INCREASE THE NORTHERLY FLOW THROUGH MON WITH THE GRADIENT BEGINNING TO RELAX SOME BY LATE TUE. THE LOW LEVEL FLOW WILL BECOME SE OVER THE NW WATERS LATE IN THE WEEK. ATLANTIC OCEAN... A BROAD UPPER RIDGE IS ANCHORED OVER NE FLORIDA COVERING THE W ATLC W OF 67W INTO THE GULF OF MEXICO. A SURFACE RIDGE DOMINATES THE W ATLC N OF 18N W OF 50W AND ANCHORED BY A 1029 MB HIGH JUST W OF BERMUDA. AN UPPER TROUGH CONTINUES TO MOVE ACROSS THE CENTRAL ATLC N OF 20N BETWEEN 43W-67W SUPPORTING A COLD FRONT THAT EXTENDS FROM A 1011 MB LOW NEAR 32N48W ALONG 27N48W TO 20N55W WHERE IT DISSIPATES TO OVER GUADALOUPE IN THE LESSER ANTILLES BECOMING A SHEAR AXIS OVER THE CARIBBEAN WATERS. SCATTERED TO NUMEROUS SHOWERS WITH POSSIBLE ISOLATED THUNDERSTORMS ARE WITHIN 200 NM E OF THE FRONT N OF 25N WITH SCATTERED SHOWERS WITHIN 120 NM E OF THE FRONT BETWEEN 20N-25N AND ISOLATED SHOWERS WITHIN 90 NM EITHER SIDE OF THE REMAINDER OF THE FRONT. A LARGE UPPER RIDGE DOMINATES MUCH OF THE NE ATLC N OF 28N. A SMALL UPPER LOW IS TO THE S CENTERED NEAR 26N24W EXTENDING AN UPPER TROUGH INT THE TROPICS TO NEAR 8N20W AND GENERATING SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS WITHIN 120/150 NM OF A LINE FROM THE CAPE VERDE ISLANDS TO THE COAST OF AFRICA NEAR 19N16W. A SURFACE RIDGE DOMINATES THE E ATLC N OF 10N E OF 45W ANCHORED BY A 1035 MB HIGH JUST N OF THE AZORES. THIS IS LEAVING THE REMAINDER OF THE ATLC WITH FAIR WEATHER TONIGHT. W ATLC SURFACE RIDGE WILL WEAKEN AS A COLD FRONT PASSES THROUGH THE NW WATERS S OF BERMUDA MON NIGHT AND TUE. THE RIDGE WILL SHIFT SLOWLY S ACROSS THE W ATLC WED THROUGH FRI. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW