000 AXNT20 KNHC 262330 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT MON MAY 26 2008 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...TROPICAL WAVES... VERY WEAK TROPICAL WAVE ANALYZED ALONG 31N S OF 12N...OR ABOUT 1750 NM E OF THE LESSER ANTILLES...MOVING W 10-15 KT. STRONG HIGH PRES AND INCREASED TRADES E OF THE TROPICAL WAVE ALONG 53W HAVE SUBDUED MOST OF THE CYCLONIC TURNING ASSOCIATED WITH THE WAVE. IF ANYTHING...LONG-TERM SATELLITE LOOPS AND CURRENT CONVECTIVE ACTIVITY SUGGEST THE WAVE MAY BE SLIGHTLY FARTHER E ALONG 29W AND S OF 9N. A SLIGHT ADJUSTMENT MAY BE REQUIRED ON THE 27/0000 UTC SURFACE ANALYSIS. CONVECTION IS LOCATED ALONG THE ITCZ. STRONGER TROPICAL WAVE ALONG 53W S OF 22N...OR ABOUT 450 NM E OF THE LESSER ANTILLES...MOVING W 15-20 KT. THE WAVE IS AMPLIFYING AS IT APPROACHES A LARGE UPPER TROUGH LOCATED N OF THE GREATER ANTILLES AND THUS THE AXIS HAS TAKEN ON A SLIGHT NW/SE TILT. STRONG HIGH PRES AND A RESULTANT INCREASE IN TRADES HAS BUILT IN BEHIND THE WAVE AS WELL. SCATTERED MODERATE/ISOLATED STRONG CONVECTION FROM 10N-14N BETWEEN 49W-53W. SHOWER ACTIVITY WILL BEGIN SPREAD ACROSS PORTION OF THE LESSER ANTILLES LATE TUE AND WED. WEAK TROPICAL WAVE ANALYZED 71W/72W S OF 15N...NEAR THE GUAJIRA PENINSULA OF COLOMBIA...MOVING W 10 KT. THE COMPOSITE TPW PRODUCT...AS WELL AS MODEL MOISTURE FIELDS...SUGGEST THAT THE MOISTURE AXIS IS NEAR 70W (NEAR ARUBA). THIS APPEARS TO AGREE WELL WITH SATELLITE IMAGERY WHICH SHOWS N END OF THE WAVE AXIS LAGGING BACK TOWARDS PUERTO RICO IN RESPONSE TO A FRONTAL BOUNDARY/UPPER TROUGH BETWEEN HISPANIOLA AND CUBA. SCATTERED MODERATE CONVECTION IS LIMITED TO PORTIONS OF VENEZUELA AND NORTHERN COLOMBIA. SCATTERED SHOWERS LIE FROM 15N-19N BETWEEN 65W-70W. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 10N10W 4N35W 6N50W 5N55W...THEN ACROSS THE SW CARIBBEAN ALONG 10N74W 11N81W 10N84W. SCATTERED MODERATE WITHIN 60 NM OF THE COAST OF GUINEA. SCATTERED MODERATE/ISOLATED STRONG WITHIN 75 NM OF AXIS BETWEEN 20W-31W. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL RIDGE AXIS EXTENDS FROM THE PACIFIC OCEAN NEWD ACROSS CENTRAL MEXICO AND THE GULF OF MEXICO TO NE FLORIDA...SPLIT BY AN UPPER TROUGH ROUGHLY FROM MOBILE ALABAMA SWD ALONG 87W. A SURFACE RIDGE OF HIGH PRES LIES ALONG THE N GULF COAST WITH E/SE LOW-LEVEL FLOW DOMINATING THE OFFSHORE WATERS. THE REMNANTS OF THE BACK-DOOR COLD FRONT WHICH CROSSED FLORIDA A FEW DAYS AGO IS STILL VISIBLE FROM THE YUCATAN CHANNEL TO SE LOUISIANA AND IS STILL PRODUCING SCATTERED SHOWERS/TSTMS ACROSS THE CENTRAL GULF FROM 24N-27N BETWEEN 87W-89W. OTHERWISE...MODERATE/STRONG SUBSIDENCE COVERS THE ENTIRE AREA AND IS LIMITING WIDESPREAD CLOUD COVER AND CONVECTION EXCEPT FOR AREAS OVER THE MEXICAN PLATEAU AND SIERRA MADRES. DEEPER MOISTURE IS EXPECTED TO RETURN TO THE AREA...BEGINNING OVER THE SE PART...BY THU. CARIBBEAN... AN AMPLIFIED UPPER LEVEL TROUGH OVER THE W ATLC EXTENDS ACROSS EASTERN CUBA THEN WWD ACROSS THE CAYMAN ISLANDS TO BELIZE WITH A HEALTHY FLOW OF DEEP MOISTURE BEING PULLED FROM THE EASTERN PACIFIC ACROSS CENTRAL AMERICA INTO THE W CARIBBEAN. A WEAKENING FRONTAL BOUNDARY ASSOCIATED WITH THE UPPER TROUGH EXTENDS FROM HAITI TO JAMAICA AND THE CAYMAN ISLANDS WITH SCATTERED TSTMS OCCURRING MAINLY OVER ADJACENT LAND AREAS. FARTHER S...A BROAD AREA OF LOW PRES IS TAKING SHAPE OVER THE SW CARIBBEAN IN THE GENERAL VICINITY OF 11N81W BUT CONNECTED TO AN EXTENSIVE TROUGH WHICH CONTINUES ACROSS COSTA RICA INTO THE EASTERN PACIFIC. CONVECTIVE ACTIVITY HAS WEAKENED SOMEWHAT WITH SCATTERED SHOWERS/ISOLATED TSTMS S OF 13N W OF 77W INTO CENTRAL AMERICA. THE AREA IS EXPECTED TO REMAIN DISORGANIZED DURING THE NEXT FEW DAYS WITH THE TROUGH AND ASSOCIATED MOISTURE BEGINNING TO SPREAD N ON WED. WEST ATLANTIC... A CLOSED UPPER LOW IS CENTERED NEAR 29N66W WITH A TROUGH AXIS CONTINUING SW TO THE SOUTHERN BAHAMAS AND EASTERN CUBA AND A 50-60 KT JET AXIS EXTENDING FROM 24N65W TO 32N62W. LARGE-SCALE DRYING LIES W OF THE AXIS WITH SCATTERED SHOWERS MOVING W TOWARDS FLORIDA IN FRESH NORTHEASTERLY FLOW. A STATIONARY FRONT EXTENDS FROM 31N57W TO 26N65W THEN TO EASTERN CUBA WITH SCATTERED SHOWERS/ISOLATED MODERATE CONVECTION WITHIN 180 NM OF THE BOUNDARY. THE FRONT WILL CONTINUE TO WEAKEN OVER THE NEXT 48 HRS AS LOW-LEVEL EASTERLY FLOW PUSHES IT...AND ASSOCIATED DEEPER MOISTURE...WWD TOWARDS THE BAHAMAS AND THE REST OF THE W ATLC. CENTRAL/EAST ATLANTIC... THE UPPER LEVELS OF THE E ATLANTIC ARE DOMINATED BY AN EXPANSIVE MID/UPPER LOW NEAR 28N35W WHICH SHOULD BE NEARLY STATIONARY FOR THE NEXT 24 HRS. THE LOW HAS BUILT INTO THE LOW LEVELS WHERE A SURFACE TROUGH EXTENDS FROM 28N40W TO 23N30W...BEING PUSHED SW BY A 1030 MB HIGH LOCATED JUST SW OF THE AZORES. AS USUAL...THERE IS VERY LITTLE DEEP MOISTURE E OF 45W AND THUS VERY LITTLE CONVECTION EXCEPT NEAR THE ITCZ. A LARGE UPPER HIGH IS CENTERED VERY NEAR DAKAR SENEGAL WITH AN UPPER RIDGE AXIS EXTENDING NWD TO 32N23W...AND TRANSITIONING INTO A LARGE UPPER TROUGH OVER SW EUROPE AND NW AFRICA. AN ASSOCIATED COLD FRONT IS MOVING E ACROSS ALGERIA AND IS PRODUCING DUST AND SANDSTORMS IN ITS WAKE. $$ BERG