000 AXNT20 KNHC 250515 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT SUN APR 25 2010 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0445 UTC... ...ITCZ... THE ITCZ IS ANALYZED ALONG 10N13W 7N18W 3N30W 3N44W 1N51W. CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION ARE FROM 3N TO INLAND OVER SW AFRICA BETWEEN THE PRIME MERIDIAN AND 7W...FROM THE EQUATOR TO 6N BETWEEN 9W-36W...AND FROM 1N-7N BETWEEN 41W-54W INCLUDING THE COAST OF SOUTH AMERICA. ...DISCUSSION... GULF OF MEXICO... A BROAD UPPER TROUGH ANCHORED OVER THE UPPER MISSISSIPPI VALLEY COVERS THE E HALF OF THE US AND THE NW GULF OF MEXICO NW OF A LINE FROM PENSACOLA FLORIDA TO BROWNSVILLE TEXAS. IT WAS DETERMINED THAT THE PREVIOUS ANALYZED FRONT IS ACTUALLY A SURFACE TROUGH WITH THE FRONT RELOCATED BACK ALONG THE COAST OF TEXAS BASED ON PRESSURE TENDENCIES. THE STATIONARY FRONT RUNS ALONG THE COAST OF TEXAS FROM FAR SW LOUISIANA TO BETWEEN CORPUS CHRISTI AND BROWNSVILLE. THE SURFACE TROUGH ENTERS THE GULF WATERS OVER VERMILION BAY LOUISIANA ALONG 25N92W TO NEAR VERACRUZ MEXICO. A WEAK 1008 MB HIGH IS BETWEEN THE TROUGH AND FRONT NEAR 27N96W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS OVER THE FLORIDA PANHANDLE W OF PANAMA CITY TO MOBILE ALABAMA. ISOLATED SHOWERS ARE WITHIN 60 NM ALONG THE COAST FROM APALACHEE BAY FLORIDA TO CHANDLER SOUND OFF THE COAST OF SE LOUISIANA. A BROAD HIGH AMPLITUDE UPPER RIDGE EXTENDS ACROSS THE REMAINDER OF THE GULF WITH THE AXIS OVER THE FLORIDA PENINSULA. THE SW UPPER FLOW IS DRAWING TROPICAL MOISTURE ACROSS MEXICO TO OVER THE GULF GENERATING SCATTERED SHOWERS WITHIN 150 NM OF LINE FROM 21N96W TO 28N84W. THIS IS LEAVING THE SE GULF AND THE NW GULF CLEAR TONIGHT. CARIBBEAN SEA... A BROAD UPPER RIDGE OVER THE GULF OF MEXICO IS ANCHORED IN THE TROPICAL ATLC EXTENDING AN AXIS OVER SOUTH AMERICA OFF COLOMBIA NEAR 9N75W NW TO CUBA NEAR 22N82W TO OVER THE FLORIDA PENINSULA. MODERATE/STRONG SUBSIDENCE AND DRY STABLE AIR DOMINATES MUCH OF THE CARIBBEAN. HOWEVER...THE REMNANTS OF A FRONTAL BOUNDARY IS OVER THE NE CARIBBEAN FROM THE VIRGIN ISLANDS JUST S OF PUERTO RICO GENERATING LOW LEVEL SCATTERED SHOWERS N OF 17N E OF 75W TO OVER THE LEEWARD ISLANDS INCLUDING PUERTO RICO AND HISPANIOLA. THE PRESSURE GRADIENT BETWEEN THE LOW PRESSURE OVER THE TROPICS AND THE BUILDING SURFACE RIDGE OVER THE W ATLC CONTINUES TO GIVE THE CARIBBEAN MODERATE TO FRESH TRADE WINDS ACROSS THE AREA BANKING LOW LEVEL CLOUDS WITH SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS OVER THE SW CARIBBEAN MAINLY S OF 12N W OF 75W AND LEAVING THE REMAINDER OF THE CARIBBEAN UNDER FAIR WEATHER TONIGHT. ATLANTIC OCEAN... A SURFACE RIDGE COVERS THE W ATLC ANCHORED BY A 1019 MB HIGH NE OF THE BAHAMAS NEAR 29N73W. A BROAD AND DEEPENING AMPLITUDE UPPER TROUGH COVERS THE REMAINDER OF THE W ATLC INTO THE CENTRAL ATLC WITHIN 300/400 NM OF LINE THROUGH 32N55W TO PUERTO RICO AND SUPPORTING A DISSIPATING STATIONARY FRONT THAT ENTERS THE CENTRAL ATLC NEAR 32N38W EXTENDING SW TO 20N57W WITH THE REMNANTS INTO THE CARIBBEAN JUST S OF PUERTO RICO. A RE-ENFORCING COLD FRONT IS TO THE W ENTERING THE REGION NEAR 32N46W ALONG 27N55W TO 27N65W. SCATTERED SHOWERS ARE WITHIN 60 NM EITHER SIDE OF OF BOTH FRONTAL BOUNDARIES. A SECOND UPPER TROUGH IS OVER THE FAR E ATLC N OF 22N E OF 23W TO INLAND OVER W AFRICA SUPPORTING A WEAK STATIONARY FRONT ENTERING THE REGION NEAR 32N22W EXTENDING TO 27N25W. THIS FRONT CONTINUES TO BISECT A SURFACE RIDGE WITH A 1018 MB HIGH NEAR 26N27W. THE UPPER RIDGE ANCHORED OVER THE TROPICAL ATLC NEAR 5N34W EXTENDS AN AXIS INLAND OVER SOUTH AMERICA NEAR 5N52W AND A SECOND N TO BEYOND 32N29W COVERING THE CARIBBEAN AS WELL AS THE E AND CENTRAL ATLC AND PROVIDING DIFFLUENCE ALOFT TO GENERATE CLUSTERS OF SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS WITHIN 150 NM OF LINE FROM 21N48W TO BEYOND 32N31W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALLACE