000 AXNT20 KNHC 070607 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT MON MAY 07 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 0545 UTC. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 8N13W 4N20W 2N30W EQ35W 1S50W. ISOLATED MODERATE CONVECTION IS FROM 1S-7N BETWEEN 16W-25W. NUMEROUS CLUSTERS OF MODERATE WITH EMBEDDED ISOLATED STRONG CONVECTION IS FROM 3S-2N W OF 25W. ...DISCUSSION... GULF OF MEXICO... A BACKDOOR COLD FRONT ASSOCIATED WITH THE DEEPENING LOW OFF THE NORTH CAROLINA COAST IS PUSHING INTO THE NE GULF THIS EVENING. A PREFRONTAL TROUGH IS JUST SW OF THE FRONT. SHOWER ACTIVITY AROUND THE FRONT IS RATHER ISOLATED IN NATURE AND MAINLY LIMITED TO WITHIN 60NM EITHER SIDE OF A BILOXI TO FT MYERS LINE. MODERATE E TO SE WINDS DOMINATE THE REST OF THE GULF. BROKEN TO OVERCAST LOW CLOUDS ARE AFFECTING THE NW GULF/TEXAS COAST AGAIN TONIGHT WITH A FAIRLY SIGNIFICANT LOW LEVEL INVERSION IN PLACE. UPPER RIDGING IS OVER THE WRN GULF WHICH IS TRANSPORTING UPPER MOISTURE EWD...DOWNSTREAM FROM CONVECTION OVER MEXICO AND THE EPAC. TROUGHING ASSOCIATED WITH DEEP LAYER LOW OFF HATTERS EXTENDS INTO THE THE NE GULF. MODERATE TO STRONG NE WINDS WILL INCREASE IN THE NE GULF BEHIND THE FRONT THROUGH THIS MORNING...BENDING MORE E TO SE FURTHER W AROUND RIDGING REBUILDING INTO THE AREA. CARIBBEAN SEA... THE SFC PRESSURE PATTERN IN THE CARIBBEAN REMAINS FAIRLY WEAK DUE TO TROUGHING IN THE SW N ATLC. SHIPS AND BUOYS ARE MOSTLY REPORTING E TO NELY TRADES IN THE 10-15 KT RANGE...EXCEPT LIGHTER AND MORE VARIABLE N OF 17N WHERE THE WEAKEST GRADIENT EXISTS. THESE LIGHT TO MODERATE WINDS SHOULD CONTINUE FOR THE NEXT DAY OR TWO AS THE SUBTROPICAL RIDGE GIVES WAY TO STRENGTHENING LOW PRES OVER THE W ATLC. ISOLATED CLUSTERS OF MODERATE ITCZ CONVECTION ARE AFFECTING COLOMBIA...PANAMA...AND COSTA RICA. THE ONLY CLUSTER AFFECTING THE CARIB IS IN THE FAR SRN PORTION OFF THE COAST OF COLOMBIA NEAR 9N77W. UPPER SW FLOW BETWEEN TROUGHING OVER THE NW PORTION AND RIDGING OVER THE ERN CARIB IS SPREADING UPPER MOISTURE OVER THE CONVECTION NE THROUGH THE BASIN...MAINLY E OF 75W. WESTERN ATLANTIC... THE BIG STORY IS THE STRENGTHENING LOW PRES SYSTEM OFF THE CAROLINA COASTLINE....ANALYZED 1005 MB NEAR 34N72W. A BACK DOOR COLD FRONT IS PROGRESSING SWD FROM THE LOW TO SOUTH CENTRAL FLORIDA. SCATTERED SHOWERS WITH ISOLATED TSTMS WITH THE FRONT ARE MAINLY WITHIN 120NM OF THE FRONT...THOUGH MIAMI RADAR AND LIGHTNING DATA DEPICT TSTMS ARE MORE SCATTERED BETWEEN SFL AND THE WRN BAHAMAS. THE MAIN IMPACT WITH THIS SYSTEM IS THE STRONG WINDS AND LARGE SEAS AS A VERY TIGHT PRES GRADIENT HAS SET UP BETWEEN THE LOW AND STRONG HIGH PRES OVER THE NORTHEAST STATES. BUOY 41001 E OF HATTERAS IS REPORTING 55 KT NE WINDS WITH 36' SEAS. GLOBAL MODELS ARE NOW IN PRETTY GOOD AGREEMENT SHOWING THE SYSTEM STRENGTHENING A LITTLE FURTHER AS IT GENERALLY MOVES SSW TO A POSITION OFF NE FLORIDA BY TUE. SEVERAL MODELS ARE ALSO SHOWING THE SYSTEM BECOMING LESS FRONTAL IN NATURE OVER THE NEXT COUPLE OF DAYS. MARINE IMPACTS ARE EXPECTED TO BE SIGNIFICANT IN THE NW PORTION OF THE AREA THROUGH MIDWEEK...REFER TO MIAHSFAT2 FOR DETAILS S OF 31N. FARTHER E...A WEAK 1010 MB LOW LOCATED NEAR 28N62W ATTACHED TO A SFC TROUGH IS EXPECTED TO DISSIPATE OVER THE NEXT 24 HOURS. CENTRAL AND EASTERN ATLANTIC... STRONG AZORES HIGH IS IN CONTROL OF THE PATTERN ACROSS THE ATLC E OF 55W. THIS HIGH IS PRODUCING A LARGE AREA OF MODERATE TO FRESH TRADES...STRONGEST E OF 25W WHERE THE PRES GRADIENT IS TIGHTENED DUE TO LOWER PRES OVER AFRICA. SCATTERED STRATOCUMULUS COVER MUCH OF THE REGION...EXCEPT S OF 18N E OF 28W WHERE THIS LOW-LEVEL CLOUD DECK IS ERODED BY SAHARAN DUST. AN UPPER LOW IS W OF THE CANARY ISLANDS NEAR 30N24W BUT DOES NOT APPEAR TO BE GENERATING MUCH IN THE WAY OF SENSIBLE WEATHER. $$ WILLIS