000 AXNT20 KNHC 301157 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT FRI MAY 30 2008 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF SOUTH AMERICA...AND 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1015 UTC. ...SPECIAL FEATURE... TROPICAL STORM ALMA WAS DOWNGRADED AT 30/0900 UTC TO A TROPICAL DEPRESSION. TROPICAL DEPRESSION ALMA IS INLAND OVER HONDURAS CENTERED NEAR 14.6N 87.6W AT 30/0900 UTC WHICH IS ABOUT 40 NM NW OF TEGUCIGALPA HONDURAS MOVING NNW AT 10 KT. MAXIMUM SUSTAINED WIND SPEED IS 25 KT WITH GUSTS TO 30 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1005 MB. ALMA IS EXPECTED TO CONTINUE MOVE MORE NW THEN WESTWARD OVER THE NEXT COUPLE OF DAYS DUE TO THE BUILDING HIGH SURFACE PRESSURE OVER THE S US AND N GULF OF MEXICO CLIPPING THE GULF OF HONDURAS. ALMA SHOULD BECOME A REMNANT LOW IN ABOUT 12 HOURS THEN DISSIPATE BY 48 HOURS. ALTHOUGH THE WINDS WILL CONTINUE TO WEAKEN HEAVY RAINFALL WILL CONTINUE FROM COSTA RICA...THROUGH PORTIONS OF NICARAGUA... HONDURAS...EL SALVADOR...GUATEMALA...AND BELIZE DURING THE NEXT COUPLE OF DAYS AS A STEADY STREAM OF TROPICAL MOISTURE LIFTS N FROM THE PACIFIC AND POSSIBLE RE-FORMATION OF ALMA OVER THE GULF OF HONDURAS OR A SECOND LOW FORMING IN THE WAKE OF ALMA. TOTAL RAINFALL ACCUMULATIONS OF 10-15 IN ARE POSSIBLE WITH ISOLATED AMOUNTS UP TO 20 IN...ESPECIALLY OVER THE HIGHER TERRAIN AND COULD PRODUCE FLASH FLOODS AND MUD SLIDES. SEE LATEST NHC INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPEP1/WTPZ31 KNHC AND THE FULL FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP1/WTPZ21 KNHC FOR MORE DETAILS. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 33W/34W S OF 16N MOVING W 15 KT. MIMIC-TPW SHOWS A WELL-DEFINED DEEP-LAYERED MOISTURE SURGE EXTENDING FROM THE TROPICS NWD TO ABOUT 16N EVEN WITH A WEAK SIGNATURE ON SATELLITE IMAGERY. ANY CONVECTION IS CONCENTRATED ALONG THE ITCZ AXIS AND FURTHER SOUTH. TROPICAL WAVE IS ALONG 49W S OF 8N MOVING W 10-15 KT. THIS POSITION IS BASED PRIMARILY ON MIMIC-TPW. THE WAVE IS AT A VERY LOW AMPLITUDE AND SO EMBEDDED WITHIN THE ITCZ...SATELLITE SIGNATURE IS INDISCERNIBLE. ANY CONVECTION IS CONCENTRATED ALONG THE ITCZ AXIS. TROPICAL WAVE IS IN THE CENTRAL CARIBBEAN ALONG 75W S OF 20N MOVING W 10-15 KT. WAVE REMAINS EMBEDDED WITHIN AN EXTREMELY MOIST ENVIRONMENT ASSOCIATED WITH THE TROPICAL DEPRESSION ALMA. THE AXIS REMAINS DIFFICULT TO LOCATED. SCATTERED MODERATE/ ISOLATED STRONG CONVECTION IS INLAND OVER N COLOMBIA. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 7N10W 3N26W 6N34W 4N41W 5N48W 4N52W. SCATTERED MODERATE/STRONG CONVECTION IS FROM 1N-10N BETWEEN 13W-17W...N OF 2N TO INLAND OVER SW AFRICA BETWEEN 10W-23W AND WITHIN 90 NM ALONG THE COAST OF SW AFRICA BETWEEN 1W-3W. CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION ARE WITHIN 150 NM OF THE ITCZ AXIS FROM 34W-45W AND FROM 4N TO THE EQUATOR BETWEEN 29W-37W. SMALL CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE WITHIN 50 NM OF THE ITCZ AXIS W OF 45W TO THE COAST OF SOUTH AMERICA. ...DISCUSSION... GULF OF MEXICO... AN UPPER HIGH REMAINS CENTERED ALONG THE PACIFIC COAST OF MEXICO NEAR MAZATLAN WITH THE RIDGE AXIS EXTENDING NW ACROSS E TEXAS TO CENTRAL MISSISSIPPI. A NARROW UPPER TROUGH AXIS EXTENDS FROM THE NE GULF SW TO 25N92W BECOMING A SHEAR AXIS TO NEAR TUXPAN MEXICO. BROAD UPPER RIDGE ASSOCIATED WITH TROPICAL DEPRESSION ALMA COVERS THE S GULF S OF THE ABOVE UPPER TROUGH/SHEAR AXIS. MODERATE/STRONG SUBSIDENCE LIES NW OF THE UPPER RIDGE WHILE DEEP MOISTURE IS REMAINS FROM THE S OVER THE CARIBBEAN. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE EMBEDDED IN THE DEEP LAYER MOISTURE ACROSS THE BAY OF CAMPECHE ACROSS THE YUCATAN THROUGH THE YUCATAN CHANNEL TO OVER W CUBA. OTHERWISE THE REMAINDER OF THE GULF IS EXPERIENCING FAIR WEATHER. THE SURFACE RIDGE THAT EXTENDS FROM THE W ATLC COVERS THE N GULF/E US AND WILL CONTINUE TO BUILD OVER THE NEXT COUPLE OF DAYS. CARIBBEAN... TROPICAL DEPRESSION ALMA IS INLAND OVER CENTRAL AMERICA AND IS ADVECTING DEEP TROPICAL MOISTURE FROM OVER THE FAR E PACIFIC ACROSS MUCH OF THE CARIBBEAN W OF 70W. UPPER LEVEL OUTFLOW IS SPREADING AWAY FROM ALMA WITH THE ASSOCIATED UPPER HIGH COVERING THE ENTIRE CARIBBEAN. A SURFACE TROUGH OVER THE NW CARIBBEAN EXTENDS FROM INLAND OVER HONDURAS NEAR 15N86W ALONG 18N85W TO 20N83W. SCATTERED MODERATE/STRONG WITH EMBEDDED NUMEROUS STRONG CONVECTION IS WITHIN 90 NM OF LINE FROM 15N80W 18N82W TO THE TROUGH AXIS NEAR 19N85W. CLUSTERS OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS COVER THE AREA N OF 15N TO OVER THE GREATER ANTILLES FROM OVER HISPANIOLA THROUGH THE YUCATAN CHANNEL TO OVER THE YUCATAN PENINSULA AND THE AREA S OF 15N W OF 80W TO INLAND OVER CENTRAL AMERICA. MOSTLY CLEAR SKIES COVER THE E CARIBBEAN WITH SOME HIGH CIRRUS CLOUDS OVER PUERTO RICO THROUGH THE LEEWARD ISLANDS. ATLANTIC... DEEP LAYERED TROUGH IS DIPPING S OVER THE W ATLC N OF 27N W OF 67W INTO THE E COAST OF FLORIDA WITH THE ASSOCIATED STATIONARY FRONT DISSIPATING ALONG THE N PERIPHERY OF THE REGION. A SURFACE TROUGH IS S OF THE UPPER TROUGH EXTENDING FROM 27N75W ACROSS THE N BAHAMA ISLANDS TO THE N COAST OF CUBA NEAR 23N80W GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 90 NM OF THE TROUGH AXIS MOVING ONSHORE OVER S FLORIDA. AN UPPER RIDGE EXTENDS FROM NEAR 25N65W NE TO BEYOND 32N55W. A SECOND SURFACE TROUGH EXTENDS FROM 25N68W TO N OF HISPANIOLA NEAR 20N72W GENERATING SCATTERED SHOWERS/THUNDERSTORMS WITHIN 150 NM SE OF THE TROUGH AXIS N OF 22N. A BROAD UPPER TROUGH EXTENDS FROM THE NE ATLC THROUGH 32N20W ALONG 26N35W TO 20N54W. AN UPPER HIGH IS IN THE E TROPICAL ATLC BETWEEN THE COAST OF W AFRICA AND THE CAPE VERDE ISLANDS WITH THE UPPER RIDGE AXIS EXTENDING W ACROSS THE TROPICAL ATLC. BROAD SUBTROPICAL RIDGE COVERS THE ENTIRE ATLC AND INTO THE E US/N GULF OF MEXICO WITH A WEAKNESS IN THE AREA AROUND BERMUDA WHERE THE DISSIPATING FRONT EXTENDS ALONG THE N PERIPHERY OF THE REGION WITH A 1026 MB HIGH CENTERED NEAR 32N39W. $$ WALLACE