000 AXNT20 KNHC 252341 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT TUE APR 25 2006 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...WEATHER OBSERVATIONS... RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 7N11W 4N20W 3N35W 3N51W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS NOTED WITHIN 60 NM N AND WITHIN 240 NM S OF THE AXIS BETWEEN 13W AND 22W AND WITHIN 180 NM EITHER SIDE OF AXIS W OF 41W. ...DISCUSSION... GULF OF MEXICO... A SHORTWAVE RIDGE HAS SHIFTED E AND NOW LIES N TO S OVER FLORIDA ALONG 82W. A SHORTWAVE TROUGH EXTENDS ALONG 32N93W 26N96W TO AN MID TO UPPER CYCLONE OVER GUATEMALA AT 17N90W WITH THE ASSOCIATED SURFACE LOW 1007 MB NEAR 19N90W. THE ASSOCIATED SURFACE LOW OVER TEXAS IS NEAR 32N95W WITH A COLD TRAILING W ACROSS CENTRAL TEXAS. AN OUTFLOW BOUNDARY IS MOVING SE ACROSS THE N CENTRAL COASTAL PLAINS WITH ITS DEBRIS MOISTURE NOW FANNING OUT OVER THE EXTREME N CENTRAL GULF WATERS. A THIN BAND OF MOISTURE...ORIGINATING FROM CONVECTION THAT FLARED OVER CENTRAL AMERICA NEAR THE CYCLONE...IS STREAMING NE ACROSS THE YUCATAN CHANNEL AND THE STRAITS OF FLORIDA. ANOTHER BAND OF UPPER MOISTURE IS NOTED WITH 15 NM EITHER SIDE OF LINE 24.5N92W 29N88W. CARIBBEAN SEA... ALOFT...A SHORTWAVE RIDGE DOMINATES THE CARIBBEAN WITH ITS MEAN AXIS EXTENDING S TO N ALONG 75W WITH THE UPPER FLOW BECOMING NEARLY ZONAL E OF 72W. DEBRIS MOISTURE FROM CONVECTION S OF 11N BETWEEN 78W AND 82W CONTINUES TO SPREAD NE TO NEAR 14N78W THEN TURNS E AND CONTINUES ACROSS THE NORTHERN CARIBBEAN WATERS INTO THE TROPICAL ATLC. AFTERNOON CONVECTION WAS ENHANCED OVER JAMAICA...MOST OF CUBA ...HISPANIOLA AND PUERTO RICO WITH THE DEBRIS MOISTURE SPREADING NE...BUT EVAPORATING IN THE DRY UPPER AIR THAT ACCOMPANIED THE RIDGE. ATLANTIC OCEAN... A SHORTWAVE RIDGE HAS ITS AXIS OVER FLORIDA ALONG 82W WITH THE ANTICYCLONIC FLOW COVERING THE WATERS W OF 75W WHERE THE UPPER FLOW THEN TURNS CYCLONIC INTO A LONGWAVE TROUGH WITH AXIS ALONG 32N61W 15N55W. A MOISTURE PLUME IS MOVING E OFF THE FLORIDA COAST ALONG 28N AND ACROSS THE RIDGE. AT THE LOW LEVELS...A COLD FRONT EXTENDS ACROSS THE NW ATLC WATERS FROM 32N34W TO 26N43W BECOMING STATIONARY TO 21N62W. OVERCAST MULTILAYERED CLOUDS AND SCATTERED SHOWERS ARE NOTED WITHIN 60 NM OF THE FRONT. A SURFACE HIGH 1021 MB IS NEAR 24N52W AND SHIFTING SLOWLY SE WITH TIME. A RIDGE EXTENDS SW TO THE STRAITS OF FLORIDA. E OF THE FRONT... HIGH PRES NEAR 36N22W 1025 MB RIDGES SW ALONG 32N28W TO 26N37W. THE E ATLC IS DOMINATED ALOFT BY A LONGWAVE TROUGH WITH AN EMBEDDED CYCLONE NEAR 32N3E TRAILING A TROUGH SW ALONG 27N5W 20N13W 10N28W. A BAND OF DRY UPPER AIR IS NOTED WITHIN 180 NM EITHER SIDE OF LINE 28N6E 22N4W THEN THE DRY AIR WIDENS TO WITHIN 480 NM EITHER SIDE OF LINE 28N7W 12N33W. A BROAD UPPER ANTICYCLONE IS NOTED OVER AFRICA NEAR 16N16E WITH A RIDGE EXTENDING W OFF THE W AFRICAN COAST AT 5N9W. UPPER DIFFLUENCE IS ENHANCING ITCZ CONVECTION DESCRIBED ABOVE. $$ NELSON