000 AXNT20 KNHC 272353 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT TUE MAY 27 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... WEAK TROPICAL WAVE ANALYZED ALONG 32W S OF 9N. LONG-TERM SATELLITE LOOPS INDICATE THAT THE WAVE REMAINS SUBDUED BY THE SUBTROPICAL HIGH AND MAY BE LOCATED A LITTLE FARTHER W NEAR 35W/36W IN THE VICINITY OF A SWIRL WITHIN THE ITCZ. BASED ON THE ANALYZED POSITION YESTERDAY...THIS WOULD GIVE THE WAVE A MEAN SPEED OF ABOUT 15 KT. A SLIGHT ADJUSTMENT OF THE POSITION WILL BE INDICATED ON THE 28/0000 UTC ANALYSIS. NO SIGNIFICANT CONVECTION. AMPLIFIED TROPICAL WAVE FROM 7N57W TO 23N59W...ABOUT 150 NM E OF THE LESSER ANTILLES...MOVING W 10-15 KT. THE WAVE HAS A NW/SE TILT DUE TO A NORTHEASTERLY SURGE IN THE TRADES...WHICH INCREASE TO 20 KT BEHIND THE AXIS. SCATTERED SHOWERS/ISOLATED MODERATE CONVECTION IS WITHIN 75 NM OF THE AXIS. THIS ACTIVITY WILL BEGIN TO SPREAD ACROSS THE LEEWARD/WINDWARD ISLANDS TONIGHT THEN TO THE VIRGIN ISLANDS/PUERTO RICO ON WED. THE TRADES WILL ALSO INCREASE OVER THE ISLAND CHAIN LATER TONIGHT AFTER THE WAVE PASSAGE. TROPICAL WAVE ALONG 74W/75W S OF 19N...FROM NORTHERN COLOMBIA TO THE WINDWARD PASSAGE...MOVING W 10-15 KT. THE WAVE IS LOCATED IN THE VICINITY OF A LARGE INCREASE IN SHOWER/TSTM ACTIVITY OFF THE COLOMBIAN COAST AND OTHER SHOWERS MOVING NW ACROSS HAITI AND JAMAICA. THE WAVE POSITION AGREES WELL WITH EXTRAPOLATION AND THE CIMSS 850 MB RELATIVE VORTICITY TRACKER. THE WAVE IS EXPECTED TO INTERACT WITH THE BROAD AREA OF LOW PRES OVER THE SW CARIBBEAN AND LEAD TO A NORTHWARD SURGE IN DEEP MOISTURE OVER THE REST OF THE W CARIBBEAN THROUGH THU. NUMEROUS SHOWERS/ ISOLATED TSTMS S OF 14N BETWEEN 73W-80W. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 8N10W 2N31W 3N43W 1N51W. SCATTERED MODERATE CONVECTION FROM 1N-9N BETWEEN 15W-29W. NUMEROUS MODERATE/ISOLATED STRONG S OF 12N W OF 77W. ...DISCUSSION... GULF OF MEXICO... A BROAD-SCALE UPPER RIDGE AXIS EXTENDS ACROSS THE AREA FROM CENTRAL MEXICO NE ACROSS CENTRAL FLORIDA TO THE CAROLINA COAST...INTERRUPTED BY A WEAK UPPER LOW NEAR THE MISSISSIPPI DELTA AND TROUGH CONTINUING S TO THE YUCATAN PENINSULA. MODERATE/STRONG SINKING ALOFT DOMINATES THE REGION AND EVEN LOW-LEVEL MOISTURE IS FAIRLY SCANT AT THE MOMENT. A WEAK SURFACE RIDGE LIES ALONG THE N GULF COAST AND IS PRODUCING MAINLY LIGHT/MODERATE E-SE FLOW OVER THE OFFSHORE WATERS EXCEPT FOR A NARROW JET OF 20 KT WINDS EMANATING W OF THE STRAITS OF FLORIDA. SCATTERED SHOWERS ARE TRAVELING FROM E TO W ACROSS THE E/CENTRAL GULF FROM 23N-28N E OF 90W. DEEPER MOISTURE IS EXPECTED TO SPREAD OVER THE SOUTHERN GULF WED NIGHT AND THU AND WILL LIKELY INCREASE THE CHANCE FOR SHOWERS/TSTMS. CARIBBEAN... A BROAD MONSOON GYRE LIES ACROSS THE FAR EASTERN PACIFIC...MUCH OF CENTRAL AMERICA...AND OVER THE SW CARIBBEAN WITH THE ITCZ AXIS SITUATED N OF PANAMA. SURFACE OBSERVATIONS FROM PANAMA CITY...PUERTO LIMON...AND SAN ANDRES SUGGEST THAT A WEAK AREA OF LOW PRES MAY BE LOCATED ALONG THE AXIS NEAR 10N81W BUT THE SATELLITE REPRESENTATION IS STILL MOSTLY DISORGANIZED. AN UPPER TROUGH AXIS EXTENDS FROM EASTERN CUBA ACROSS THE CAYMAN ISLANDS TO BELIZE...WITH 50 KT W/SW UPPER LEVEL FLOW STREAMING ACROSS THE CARIBBEAN AND DIFFLUENCE PRODUCING NUMEROUS MODERATE/ ISOLATED STRONG CONVECTION S OF 12N INTO PANAMA...COSTA RICA...AND SOUTHERN NICARAGUA. DEEP MOISTURE WILL BEGIN LIFTING N INTO THE NW CARIBBEAN OVER THE NEXT 24 HRS AS THE TROPICAL WAVE NEAR 75W BEGINS TO INTERACT WITH THE SYSTEM. ELSEWHERE...A WEAKENING FRONTAL BOUNDARY EXTENDS FROM EASTERN CUBA TO THE CAYMAN ISLANDS AND IS BEGINNING TO PUSH BACK TO THE NW...WHILE PRODUCING SCATTERED TSTMS ACROSS CUBA...JAMAICA...AND HISPANIOLA. FARTHER E...WIDESPREAD HIGH CLOUDINESS STREAMS E ACROSS THE EASTERN CARIBBEAN AND DEEPER MOISTURE IS EXPECTED TO INCREASE OVER THE AREA OVERNIGHT AND WED AS THE TROPICAL WAVE NEAR 58W MOVES W. ATLANTIC... A CUT-OFF MID/UPPER LOW IS LOCATED JUST SW OF BERMUDA NEAR 31N67W WITH A TROUGH AXIS EXTENDING SW TO THE S/CENTRAL BAHAMAS AND EASTERN CUBA. WIDESPREAD MODERATE/STRONG SUBSIDENCE LIES W OF THE TROUGH WHILE ABUNDANT TROPICAL MOISTURE IS STREAMING NE WITHIN 800 NM E OF THE AXIS. THE FRONTAL BOUNDARY FROM 31N60W TO 26N70W TO EASTERN CUBA HAS BEGUN TO SLOWLY LIFT BACK TO THE NW AS A WARM FRONT. SCATTERED SHOWERS/TSTMS LIE N OF 24N BETWEEN 60W-69W AS WELL AS S OF 22N BETWEEN 67W-76W. TO THE E...A SHARP UPPER RIDGE AXIS EXTENDS FROM 20N55W TO 31N51W...MARKING THE DIVISION BETWEEN THE MOIST AIR MASS TO THE W AND STRONGER DRYING OVER THE CENTRAL ATLANTIC DUE TO A LARGE UPPER LOW NEAR 29N35W. AN AXIS EXTENDS FROM THIS LOW SW TO 13N49W WITH BROAD SW/W FLOW CONTINUING E TOWARDS AFRICA WITH JET CORE SPEEDS OF 50-60 KT JUST SE OF THE LOW. ALSO...AN UPPER HIGH IS LOCATED NEAR THE CAPE VERDE ISLANDS AND COUPLE WITH THE TROUGH IS DRAWING DEEP TROPICAL MOISTURE NWD BETWEEN 23W-37W. A SURFACE TROUGH IS EMBEDDED WITHIN THE SUBTROPICAL RIDGE FROM 27N43W TO 21N33W WITH A BROKEN CLOUD DECK AND POSSIBLE EMBEDDED SHOWERS WITHIN 240 NM NE OF THE AXIS. $$ BERG