000 AXNT20 KNHC 042351 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT TUE APR 04 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 2N30W 1N8W 2N46W. WEAK TROUGH/POSSIBLE TROPICAL WAVE IS EMBEDDED IN THE ITCZ NEAR S AMERICA ALONG 49W S OF 4N BRINGING ISOLATED TSTMS S OF 5S W OF 47W. ISOLATED TSTMS ARE ALSO WITHIN 45 NM OF 4N19W. ...DISCUSSION... GULF OF MEXICO... THE ONLY GAME IN TOWN IS A COLD FRONT THAT CUTS THRU CENTRAL FLORIDA APPROACHING LAKE OKEECHOBEE INTO THE GULF NEAR 26.5N88W THEN NW TO NEAR GALVESTON BAY. DAYTIME HEATING AND AN UPPER SHORTWAVE PASSING THRU THE NE GULF HAVE COMBINED TO FORM A FEW TSTMS ALONG THE FRONT... SOME SEVERE WITH GOLFBALL-SIZED HAIL. OTHERWISE CLOUDS AND STRONG WINDS ARE HARD TO COME BY OVER THE GULF AS WEAK HIGH PRESSURE CONTROLS OTHER PARTS OF THE AREA. THE ACTIVITY SHOULD DIE FAIRLY QUICKLY AS DIURNAL HEATS FADES. THE NEXT COLD FRONT MIGHT ENTER THE NW GULF EARLY SAT WITH A CHANCE OF RAIN. OTHERWISE.. DRY NW FLOW ALOFT DOMINATES WITH MODERATE/STRONG SUBSIDENCE ESPECIALLY IN THE BAY OF CAMPECHE. CARIBBEAN SEA... A MID-LEVEL TROUGH IS DEEPENING SLIGHTLY OVER THE NW CARIBBEAN... ASSISTING THE FORMATION OF SHOWERS/TSTMS OVER E CUBA.. JAMAICA AND HISPANIOLA. OTHER SHOWERS/TSTMS ARE S OF 16N W OF 80W. SWLY UPPER LEVEL FLOW OVER S AMERICA IS DRAWING MOISTURE ACROSS THE LESSER ANTILLES. PATCHES OF LOW-LEVEL CLOUDS WITH EMBEDDED ISOLATED SHOWERS ARE SCATTERED ACROSS THE AREA DRIVEN BY LIGHT TO MODERATE TRADE WINDS. NO BIG CHANGES ARE LIKELY WITH ANOTHER CHANCE OF RAIN TOMORROW FOR HISPANIOLA WITH A BETTER CHANCE OF RAIN FOR THE NE CARIBBEAN INCLUDING PUERTO RICO (WHICH HAD A FEW TSTMS TODAY). ATLANTIC OCEAN... COLD FRONT ENTERS THE NW ATLC NEAR 31N74W EXTENDING SW TO CENTRAL FLORIDA NEAR FT. PIERCE. ISOLATED SHOWERS ARE ALONG THE FRONT WITH A SMALL CHANCE OF A TSTM. AHEAD OF THE FRONT.. TWO WEAK TROUGHS ARE SERVING AS MECHANISMS FOR RAIN AS AN UPPER TROUGH DEEPENS OVER THE SE USA. ISOLATED TSTMS ARE FROM 20N-26N BETWEEN 63W-72W. THESE TROUGHS ARE MOVING SLOWLY NORTHWARD AROUND A LARGE CENTRAL ATLC 1023 MB HIGH NEAR 30N47W. BENEATH THE HIGH... A PESKY & PERSISTENT 1014 MB LOW IS NEAR 21.5N46.5W SUPPORTED BY AN UPPER TROUGH HELPING TO PRODUCE WIDELY SCATTERED SHOWERS/TSTMS WITHIN 120 NM OF LINE 23N42W 29N34W. THE LOW SHOULD DISSIPATE AS IT LOSES UPPER SUPPORT DUE TO THE TROUGH BYPASSING THE LOW... BUT THIS SURFACE LOW HAS HAD A WAY OF STICKING AROUND LONGER THAN EXPECTED. AN UPPER HIGH IS IN THE DEEP TROPICS NEAR 7N42W AS RIDGING IS FAR TO THE N FOR EARLY APRIL. OTHERWISE ZONAL FLOW CONTROLS MOST OF THE TROPICAL ATLC WITH AN UPPER JET RUNNING FROM 15N60W TO 20N30W. WEAK UPPER TROUGH IS IN THE SE ATLC ALONG 20W WITH LOTS OF DRY AIR ALOFT. TRADES REMAIN QUITE W OF 40W DUE TO THE LOW/TROUGH IN THE CENTRAL ATLC. SKIES ARE PARTLY CLOUDY WITH A FAIR AMOUNT OF AFRICAN DUST APPARENT FROM VISIBLE IMAGES S OF 18N ACROSS MOST OF THE REGION E OF THE LESSER ANTILLES. $$ BLAKE