000 AXNT20 KNHC 122342 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST SUN MAR 12 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 2314 UTC. ...THE ITCZ... ITCZ IS CENTERED ALONG 7N5W 1N35W INTO S AMERICA NEAR 2N51W. SCATTERED SHOWERS AND ISOLATED TSTMS WITHIN 100 NM EITHER SIDE OF THE ENTIRE ITCZ. ...DISCUSSION... GULF OF MEXICO... STRONG MIDDLE TO UPPER LEVEL RIDGE DOMINATES THE GLFMEX EXTENDING FROM A ANTICYCLONE OVER THE YUCATAN PENINSULA NEWD ALONG THE E COAST OF THE UNITED STATES. AS A RESULT...THE CORE OF THE STRONGEST WESTERLIES AND ASSOCIATED DYNAMICS/LIFT REMAIN N OF THE AREA OVER THE CENTRAL UNITED STATES. AT THE SURFACE...THE COMBINATION OF BROAD LOW PRES OVER THE CENTRAL U.S. AND A 1025 HIGH NEAR BERMUDA IS MAINTAINING BRISK SE FLOW ACROSS THE ENTIRE GULF. THIS PATTERN IS CREATING AN ALMOST SUMMER-LIKE AIRMASS IN THE LOWER LEVELS WITH DEWPOINTS IN THE 60S TO 70S ACROSS THE REGION. LOOKING UPSTREAM...A BROAD MIDDLE TO UPPER LEVEL TROUGH CURRENTLY OVER THE W UNITED STATES WILL PROGRESS EWD INTO THE CENTRAL U.S. MON THEN TO THE E U.S. BY LATE TUE. THIS WILL IGNITE LEE-CYCLOGENESIS ALONG E SLOPES OF THE ROCKIES TONIGHT WHICH WILL SEND A COLD FRONT SWD REACHING THE NW GULF MON AFTERNOON. WITH THE UPPER FLOW EXPECTED TO REMAIN NEARLY ZONAL OVER THE GULF...THE FRONT WILL BECOME INCREASING WEAK AS IT PUSHES SWD THROUGH FLORIDA LATE TUE CLEARING THE S PENINSULA LATE WED. STILL...LOW LEVEL MOISTURE POOLING ALONG THE BOUNDARY WILL LIKELY PRODUCE SOME SCATTERED SHOWERS AND ISOLATED TSTMS RIGHT ALONG THE LEADING EDGE OF THE FRONT. THE MOST WIDESPREAD OF THIS ACTIVITY IS CURRENTLY EXPECTED OVER THE NE GULF AND N FLORIDA TUE. ELSEWHERE...A WEAK LOW-LEVEL ELY DISTURBANCE OVER THE BAHAMAS MAY CAUSE SOME SHOWERS OVER S FLORIDA TONIGHT AND MON AS IT CONTINUES WNW AROUND THE W PERIPHERY OF THE SUBTROPICAL RIDGE. N CARIBBEAN SEA... THE AFOREMENTIONED ANTICYCLONE OVER THE YUCATAN PENINSULA NOSES SEWD ACROSS THE N CARIBBEAN WITH A WEAK MIDDLE TO UPPER LEVEL TROUGH OVER N PORTIONS OF S AMERICA. THE RESULTING UPPER-LEVEL FLOW BETWEEN THESE FEATURES IS STRONGLY CONFLUENT PRODUCING MODERATE TO STRONG SUBSIDENCE AND VERY DRY/STABLE CONDITIONS ALOFT ACROSS THE ENTIRE CARIBBEAN AND CENTRAL AMERICA. AT THE LOWER LEVELS...THE W EXTENT OF AN OLD REMNANT FRONTAL TROUGH OVER THE CENTRAL TO E ATLANTIC HAS FRAGMENTED FORMING A SCREAMING EAGLE OVER THE E CARIBBEAN. THE FEATURE IS PRODUCING SCATTERED SHOWERS AND TSTMS FROM 13.5N TO 16.5N E OF 67W. THIS ACTIVITY WILL SPREAD WESTWARD TONIGHT REACHING THE CENTRAL CARIBBEAN BY EARLY MON AND THE W CARIBBEAN LATE TUE. ASSOCIATED SHOWERS/TSTMS ARE EXPECTED TO REMAIN PRIMARILY S OF THE GREATER ANTILLES AND N OF S AMERICA. ELSEWHERE...BRISK TRADES ON THE ORDER OF 20-30 KT WILL CONTINUE ACROSS MUCH OF THE CARIBBEAN SEA THROUGH MON THEN GRADUALLY WEAKEN TUE AND WED AS THE ATLANTIC SUBTROPICAL RIDGE SHIFTS EWD. ATLANTIC OCEAN... A LARGE-SCALE RIDGE-TROUGH PATTERN PREVAILS IN THE MIDDLE TO UPPER LEVELS WITH A RIDGE OVER THE W ATLANTIS BETWEEN BERMUDA AND THE E COAST OF THE U.S. AND A BROAD/FLAT TROUGH OVER THE CENTRAL TO E ATLANTIC. THE CENTRAL TO E ATLANTIC TROUGH IS COMPRISED OF MULTIPLE SHORT-WAVE DISTURBANCES...THE MOST NOTABLE CURRENTLY DROPPING SEWD OVER THE CENTRAL ATLC. THIS FEATURE IS DRAGGING A MODERATELY STRONG COLD FRONT SWD INTO THE DISCUSSION AREA...CURRENTLY ALONG 32N42W 29N55W 32N69W. MOST OF THE UPPER DYNAMICS ALONG THE FRONT REMAIN JUST N OF THE AREA WITH ONLY A 150 NM WIDE BAND OF BROKEN/OVERCAST LOW/MID CLOUDINESS AND SCATTERED SHOWERS NOTED AHEAD OF THE FRONT. ELSEWHERE... GENERALLY TRANQUIL WEATHER PREVAILS ESPECIALLY OVER THE FAR E ATLANTIC WHERE EARLIER VISIBLE SATELLITE IMAGERY SHOWS A STRONG SAHARAN AIR LAYER OUTBREAK EQUATORWARD OF A LINE FROM 32N28W 18N50W. THE HIGHEST CONCENTRATION OF DUST APPEARS TO BE S OF 20N E OF 50W WITH VERY HIGH CONCENTRATIONS NOTED OVER AND JUST SE OF THE CAPE VERDE ISLANDS. AVAILABLE OBSERVATIONS INDICATE OCCASIONAL VISIBILITIES BELOW 5 SM WITHIN THIS AREA. AT THE SURFACE...THE SUBTROPICAL RIDGE EXTENDS FROM A 1027 MB HIGH NEAR 31N70W ESE ALONG 26N55W THEN NE TO 31N37W. $$ RHOME