000 AXNT20 KNHC 290008 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT FRI APR 28 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 4N5W 1N23W 1N32W 1N41W EQ50W. SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN 60 NM OF THE AXIS BETWEEN 9W-16W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 30 NM OF THE AXIS BETWEEN 30W-34W. SCATTERED MODERATE CONVECTION IS NOTED FROM EQ-1N BETWEEN 35W-41W. ...DISCUSSION... GULF OF MEXICO... AN UPPER ANTICYCLONE IS CENTERED OVER THE E PAC NEAR 12N106W. A RIDGE EXTENDS N ACROSS OLD MEXICO ALONG 22N102W...THEN SHARPENS AS IT CRESTS NORTHEAST ACROSS CENTRAL TEXAS WITH MEAN RIDGE AXIS FROM 32N96W TO 25N98W. THE UPPER FLOWS DIVES SOUTHEASTWARD ACROSS THE EASTERN GULF TO ACROSS THE FLORIDA PENINSULA...CUBA...AND THE YUCATAN PENINSULA. A MOISTURE PLUME...ORIGINATING FROM ITCZ CONVECTION OVER THE E PACIFIC BETWEEN 108W-125W IS BEING EJECTED NORTHEASTWARD AHEAD OF A MID/UPPER LEVEL TROUGH OVER THE EASTERN PACIFIC ALONG THE PERIPHERY OF THE RIDGE...OR ROUGHLY WITHIN 250 NM EITHER SIDE OF LINE 21N110W TO 27N100W TO 32N91W TO 29N84W WHERE IT EVAPORATES. MODERATE SUBSIDENCE AND ASSOCIATED DRY IS INHIBITING ANY CONVECTION FROM DEVELOPING OVER THE GULF AT THIS TIME. ONLY SCATTERED LOW CLOUDS MOVING QUICKLY NORTH AND NORTHWEST IN RETURN SOUTHERLY FLOW ARE NOTED ON THE LAST FEW FRAMES OF VISIBLE IMAGERY OVER THE CENTRAL AND WESTERN GULF. AT THE SURFACE..HIGH PRESSURE RIDGING IS BUILDING SOUTHWARD THROUGH 21N83W TO 23N82W. CARIBBEAN SEA... AN UPPER LEVEL ANTICYCLONE IS ESTIMATED NEAR 6N45W BASED ON WATER VAPOR IMAGERY. BROAD MID/UPPER LEVEL RIDGING EXTENDS FROM THE ANTICYCLONE NORTHWEST THROUGH 6N52W TO ACROSS VENEZUELA. NORTH OF THE UPPER RIDGE...A SHORTWAVE TROUGH IS NOTED WITH ITS MEAN AXIS EXTENDING SOUTHWEST FROM THE DOMINICAN REPUBLIC TO 16N74W TO 14N80W. A JET STREAM BRANCH WITH MAXIMUM WINDS 70-90 KT ROUNDS THE BASE OF THIS TROUGH FROM 12N75W THROUGH 15N65W AND NORTHEAST ACROSS THE LEEWARD ISLANDS. CONFLUENT FLOW ON THE BACK SIDE OF THE TROUGH IS USHERING IN MODERATE TO STRONG SUBSIDENCE AND ASSOCIATED DRY AIR ACROSS ALMOST THE ENTIRE WESTERN AND CENTRAL PORTION OF THE CARIBBEAN SEA. ONLY SIGNIFICANT CONVECTION OVER SEA ALREADY OCCURRED...AND THAT WAS OVER THE ISLANDS OF HISPANIOLA...JAMAICA AND PUERTO RICO AND EASTERN CUBA. THIS ACTIVITY IS FADING OUT QUICKLY NOW THAT DAYTIME HEATING HAS BEEN LOST. RESULTANT DEBRIS MOISTURE IS SEEN MOVING QUICKLY SOUTHEASTWARD AWAY FROM THESE ISLANDS. WIDELY SCATTERED SHOWERS ARE SEEN PRIMARILY NORTH OF 16.5N AND EAST OF 66W. ELSEWHERE ...ONLY SCATTERED LOW CLOUDS WITH SOME ISOLATED SHOWERS ARE MOVING WESTWARD IN LIGHT TRADE WIND FLOW ACROSS THE SEA. ATLANTIC OCEAN... THE WESTERN SW N ATLC IS UNDER UPPER LEVEL NORTHWESTERLY FLOW WHICH MARKS THE WESTERN EXTENT OF BROAD CYCLONIC FLOW DUE TO A RATHER VIGOROUS SHORTWAVE TROUGH WITH ITS MEAN AXIS EXTENDING ROUGHLY FROM 32N70W TO 20N74W. THE CYCLONIC FLOW EXTENDS EASTWARD TO 60W. DIFFLUENCE INDICATED EAST OF THE TROUGH CONTINUES TO ENHANCE CONVECTION WELL EAST OF A SURFACE COLD FRONT THAT EXTENDS FROM A GALE CENTER NEAR 32N70W 1007 MB THROUGH 27N70W TO EASTERN CUBA WHERE IT IS BECOMING ILL-DEFINED. THIS CONVECTION CONSISTS OF THE SCATTERED MODERATE/ISOLATED STRONG TYPE AND IS FOUND GENERALLY WITHIN AN AREA BOUNDED FROM 24N-30N BETWEEN 60W-67W. WIDELY SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE SEEN SOUTH OF 24N BETWEEN 60W-65W. ONLY ISOLATED SHOWERS AND THUNDERSTORMS ARE ALONG AND WITHIN ABOUT 60 NM EAST OF THE COLD FRONT FROM 23N-26N. SCATTERED TO BROKEN LOW CLOUDS WITH ISOLATED SHOWERS MOVING SOUTH-SOUTHEAST IN CYCLONIC FLOW DUE TO THE GALE CENTER ARE PRESENT WEST OF THE COLD FRONT NORTH OF 23N. TO THE EAST OF THE SHORTWAVE TROUGH...A RATHER COMPACT MID/UPPER LEVEL RIDGING IS SEEN NORTH OF 19N BETWEEN 53W-60W. EAST OF THIS RIDGE...A LONGWAVE TROUGH CONTINUES TO DOMINATE THE CENTRAL NORTH ATLANTIC. AN EMBEDDED CYCLONE MOVING WESTWARD 15 KT IS NOTED NEAR 25N45W. MODERATE SUBSIDENCE AND DRY AIR IS NOTED NORTH OF 20N BETWEEN 50W-60W. AT THE SURFACE...HIGH PRESSURE RIDGING EXTENDS THROUGH 32N52W TO 27N63W. HIGH PRESSURE COVERS THE AREA NORTH OF 20N EAST OF 62W. OVER THE FAR EASTERN ATLANTIC...AN UPPER LEVEL ANTICYCLONE IS ESTIMATED OVER AFRICA NEAR 9N7W WITH A RIDGE EXTENDING WESTWARD THROUGH 8N25W TO 8N38W. DEBRIS MOISTURE FROM CONVECTION OF SOUTH AMERICA...AND THE ITCZ BETWEEN 24W AND 35W...IS STREAMING NORTHEAST ACROSS THE TROPICAL ATLC WATERS SOUTH OF 19N EAST OF 36W. $$ AGUIRRE