000 AXNT20 KNHC 212319 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT FRI APR 21 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 6N10W 4N20W 1N30W EQ40W 1S45W. SCATTERED SHOWERS AND ISOLATED TSTMS ARE WITHIN 350-450 NM TO THE N OF THE AXIS W OF 25W. MUCH OF THIS ACTIVITY IS BEING SHEARED TO THE N. WIDELY SCATTERED SHOWERS SURROUND THE AXIS E OF 25W. CLUSTERS OF MODERATE CONVECTION IS OFF THE W COAST OF AFRICA E OF 7W FROM 3S-4N. ...DISCUSSION... GULF OF MEXICO... MAINLY ZONAL WESTERLY UPPER LEVEL FLOW EXISTS IN THE GULF WITH A STRONG UPPER HIGH CENTERED TO THE S OF THE AREA OVER CENTRAL AMERICA AND A SHORTWAVE TROUGH TO THE N OVER TEXAS AND LOUISIANA. THE ONLY AREA OF UNSETTLED WEATHER IS IN THE EXTREME N GULF COAST WHERE A SQUALL LINE...WHICH LIES 200 NM AHEAD OF A COLD FRONT...RUNS FROM THE AL/MS BORDER OUT ACROSS THE COASTAL WATERS TO 29N90W. THIS LINE OF TSTMS IS MOVING RAPIDLY NEWD. MODERATE TO STRONG SUBSIDENCE IS KEEPING SKIES FAIR TO MOSTLY CLEAR ACROSS MUCH OF THE REGION EXCEPT FOR SOME BROKEN CLOUD COVER W OF 93W N OF 23N AHEAD OF THE COLD FRONT OVER TEXAS. LIGHT S/SSW SFC WINDS ARE COMMON ACROSS THE REGION AS HIGH PRES REMAINS IN THE W ATLC. THE COLD FRONT CURRENTLY OVER THE S CENTRAL U.S. WITH MOVE SEWD AND WILL BE LOCATED FROM THE FL PANHANDLE TO 26N89W IN 24 HOURS. THEREAFTER...THE TAIL END OF THE FRONT WILL BEGIN TO DISSIPATE AND PULL N OF THE AREA. THE FRONT MAY BRING SCATTERED SHOWERS WITH IT BUT THE MAJORITY OF THE DEEP MOISTURE WILL REMAIN N OF THE GULF COAST. HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT. CARIBBEAN SEA... A STRONG UPPER HIGH IS CENTERED IN THE EPAC OFF THE W COAST OF NICARAGUA NEAR 11N91W WITH THE UPPER LEVEL WESTERLIES PREVAILING ACROSS THE CARIBBEAN. MODERATE TO STRONG SUBSIDENCE LIES ACROSS THE ENTIRE AREA. TRADE WINDS HAVE INCREASED SLIGHTLY SINCE YESTERDAY WITH A FEW TRADE WINDS SHOWERS STREAMING ACROSS THE SEA. MORE IMPRESSIVE SHOWER ACTIVITY IS OVER AND NEAR THE LAND AREAS OF THE VIRGIN ISLANDS...PUERTO RICO AND HISPANIOLA. SAN JUAN DOPPLER RADAR INDICATES A FEW STRONG TSTMS ALONG THE NE COAST OF THE ISLAND MOVING WWD. THIS ACTIVITY IS ENHANCED BY SEA-BREEZE CONVERGENCE AND LOCAL TOPOGRAPHIC LIFT. SIMILAR CONVECTION HAS DEVELOPED OVER THE TOPOGRAPHIC AREAS OF CENTRAL AMERICA. NO BIG CHANGES ARE IN STORE FOR THE REGION THRU THE WEEKEND. TRADE WINDS MAY INCREASE SOME MORE ESPECIALLY N OF THE COLUMBIAN COAST THIS WEEKEND BEFORE RELAXING BY EARLY NEXT WEEK. ATLANTIC OCEAN... BASICALLY A RIDGE/TROUGH/RIDGE/TROUGH PATTERN EXISTS ACROSS THE ATLANTIC BASIN. NARROW AMPLIFIED UPPER RIDGING STRETCHES FROM THE BAHAMAS TO THE NE U.S. AT THE SFC...A 1023 MB HIGH IS CENTERED NEAR 31N71W. A WEAK SFC TROUGH LIES IN THE W BAHAMAS ALONG 78W FROM 26N-28N. BROKEN CLOUDS AND A FEW POSSIBLE SHOWERS ARE NEAR THIS FEATURE. A DEEP-LAYERED LOW S OF NEWFOUNDLAND HAS CARVED OUT A DEEP UPPER TROUGH WHICH STRETCHES FROM 50W-70W N OF 22N. A SWLY JET ON THE E SIDE OF THE TROUGH AXIS IS PRODUCING SHOWERS AND TSTMS FROM 21N TO BEYOND 32N BETWEEN 43W-50W. AT THE SFC...A DISSIPATING COLD FRONT ENTERS THE AREA ALONG 32N51W 27N55W THEN AS A WEAKENING SFC TROUGH TO 23N62W. A FEW THIN BANDS OF CLOUDS AND WEAK SHOWERS ARE NEAR THE FRONT. MORE ORGANIZED SHOWER ACTIVITY MAY BE AT THE TAIL END OF THE TROUGH. FARTHER EAST...SFC HIGH PRES DOMINATES THE REMAINDER OF THE BASIN WITH A 1030 MB HIGH CENTER NEAR 39N29W. A SURFACE RIDGE AXIS EXTENDS SWWD FROM THE HIGH TO 24N47W. IN THE UPPER LEVELS...AN AMPLIFIED RIDGE STRETCHES FROM 17N45W TO BEYOND 32N45W. AN UPPER TROUGH LIES E OF 28W N OF 22N. DRY/STABLE AIR COVERS MUCH OF THE E ATLC. $$ CANGIALOSI