000 AXNT20 KNHC 311759 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT SAT MAY 31 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...SPECIAL FEATURE... NEWLY FORMED TROPICAL STORM ARTHUR IS CENTERED NEAR 18.1N 88.5W OR ABOUT 45 MILES NNW OF BELIZE CITY AT 31/1700 UTC MOVING WNW 7 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1005 MB. MAXIMUM SUSTAINED WIND SPEED IS 35 KT WITH HIGHER GUSTS. SEE LATEST NHC INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT1/WTNT31 KNHC AND THE FULL FORECAST/ADVISORY UNDER AWIPS/WMO HEADER MIATCMAT1/WTNT21 KNHC FOR MORE DETAILS. DESPITE MOVING INLAND OVER BELIZE AND THE YUCATAN PENINSULA EARLIER THIS MORNING THE AREA OF LOW PRESSURE LOCATED IN THE NORTHWESTERN CARIBBEAN BECAME A TROPICAL STORM AS IT WAS CROSSING THE COAST OF BELIZE EARLY THIS MORNING. THIS IS BASED ON SATELLITE IMAGERY...SHIP DATA AND A NOAA BUOY 42056 WHICH REPORTED SUSTAINED WINDS OF TROPICAL STORM FORCE. SCATTERED MODERATE ISOLATED STRONG CONVECTION ASSOCIATED WITH ARTHUR IS FROM 16N-21N BETWEEN 82W-89W. WEAKENING IS ANTICIPATED AS STORM MOVES OVER LAND WITH A POSSIBILITY THAT ARTHUR REGAINS TROPICAL STORM STATUS IF IT MOVES BACK OVER WATER IN THE BAY OF CAMPECHE. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 19W S OF 14N MOVING W NEAR 10 KT. MIMIC-TPW CLEARLY SHOWS THE WAVE AXIS AND A MID LEVEL ROTATION IS OBSERVED ON SATELLITE IMAGERY NEAR 7N. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 200 NM OF THE AXIS BETWEEN 3N-11N. TROPICAL WAVE IS ALONG 43W/44W S OF 15N MOVING W 15 KT. MIMIC-TPW SHOWS A WELL-DEFINED WAVE AXIS WITH A BROAD SIGNATURE ON SATELLITE IMAGERY. CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION ARE WITHIN 90 NM OF A LINE FROM 1N40W TO 8N41W. SIMILAR CONVECTION IS FROM 5N-7N BETWEEN 44W-47W. TROPICAL WAVE IS ALONG 57W S OF 11N MOVING W NEAR 15 KT. THIS WAVE WAS RE-POSITIONED AT 1200 UTC BASED PRIMARILY ON MIMIC-TPW AND WELL-DEFINED INVERTED-V SATELLITE SIGNATURE. SCATTERED MODERATE CONVECTION IS WITHIN 200 NM OF THE WAVE AXIS FROM 6N-9N. TROPICAL WAVE IN THE W CARIBBEAN IS ALONG 81W/82W S OF 21N MOVING W 10-15 KT BASED ON EXTRAPOLATION. WAVE REMAINS EMBEDDED BENEATH A BROAD UPPER RIDGE AND AN ABUNDANCE OF UPPER LEVEL MOISTURE THAT COVERS THE CARIBBEAN MASKING ANY SIGNATURE. NO ASSOCIATED CONVECTION. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 12N15W 8N18W 6N21W 2N31W 2N42W 1N46W AND INTO NE BRAZIL NEAR 1N50W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM THE EQUATOR TO 3N BETWEEN 24W-27W. SIMILAR CONVECTION IS WITHIN 60 NM OF A LINE FROM 3N39W TO 2S40W. ALSO SCATTERED MODERATE CONVECTION IS WITHIN 120 NM N OF THE AXIS BETWEEN 48W-52W. ...DISCUSSION... GULF OF MEXICO... BROAD UPPER RIDGE CENTERED OVER NORTHERN MEXICO EXTENDS ALONG THE N GULF COAST TO THE FLORIDA PANHANDLE COVERING THE GULF N OF 23N. WEAK UPPER RIDGE COVERS THE NE GULF N OF 25N E OF 85W ACROSS FLORIDA INTO THE FAR W ATLC. BROAD UPPER RIDGE COVERS THE S GULF ANCHORED OVER NEWLY FORMED TROPICAL STORM ARTHUR IN THE GULF OF HONDURAS CREATING A SHEAR AXIS ALONG 23N ACROSS THE GULF OF MEXICO. STRONG SUBSIDENCE COVERS THE N GULF WHILE DEEP MOISTURE REMAINS OVER THE S GULF TO OVER THE CARIBBEAN SEA. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE EMBEDDED IN THE DEEP LAYER MOISTURE S OF A LINE FROM THE BAY OF CAMPECHE AND S MEXICO NEAR 21N96W ALONG 22N88W INCLUDING THE YUCATAN PENINSULA TO S OF CUBA. THE N GULF CONTINUES TO EXPERIENCE FAIR WEATHER WITH LITTLE OR NO CLOUDS. A SURFACE RIDGE EXTENDS FROM THE W ATLC OVER THE GULF/SE US AND COMBINED WITH THE LOWER PRESSURE OVER THE S GULF AND CARIBBEAN WILL MAINTAIN 10-15 KT SURFACE WINDS ACROSS THE GULF FOR THE NEXT DAY OR TWO. CARIBBEAN... TROPICAL STORM ARTHUR FORMED NEAR THE BELIZE COAST THIS MORNING AND IS INLAND OVER BELIZE AND THE YUCATAN PENINSULA. ARTHUR WILL CONTINUE TO MOVE ACROSS THE YUCATAN WITH SCATTERED SHOWERS AND THUNDERSTORMS WHICH CONTAIN VERY HEAVY RAINS AND FLOODS POSSIBLE THE NEXT COUPLE OF DAYS OVER PORTIONS OF HONDURAS...EL SALVADOR ...GUATEMALA...BELIZE...AND SE MEXICO. BROAD UPPER RIDGE REMAINS OVER THE CARIBBEAN ANCHORED OVER THE GULF OF HONDURAS COVERING THE ENTIRE AREA AND MAINTAINING DEEP TROPICAL MOISTURE MAINLY W OF 80W. CLUSTERS OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE OVER THE W CARIBBEAN INTO THE GULF OF MEXICO W OF 83W TO OVER CENTRAL AMERICA N OF 14N. UPPER LEVEL MOISTURE WITH EMBEDDED ISOLATED SHOWERS COVERS THE AREA N OF 16N FROM 66W-80W. MOSTLY CLEAR SKIES COVER THE REMAINDER OF THE CARIBBEAN WITH MODERATE TO STRONG EASTERLY TRADE WINDS ACROSS THE ENTIRE BASIN. ATLANTIC... UPPER LEVEL RIDGE COVERS THE FAR W ATLC ACROSS FLORIDA INTO THE NE GULF OF MEXICO. DEEP LAYERED TROUGH COVERS THE REMAINDER OF THE W ATLC N OF 20N FROM 57W-68W WITH THE ASSOCIATED COLD FRONT N OF THE REGION AND A SURFACE TROUGH EXTENDING INTO THE REGION NEAR 32N59W TO 26N68W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 200 NM E OF THE TROUGH. A SURFACE RIDGE CONTINUES TO SETTLE IN BEHIND THE FRONT/TROUGH OVER THE SE US INTO THE GULF OF MEXICO ANCHORED BY A 1024 MB HIGH N OF THE REGION AND A 1021 MB HIGH ACROSS S GEORGIA. AN UPPER TROUGH EXTENDS E/W ACROSS THE ATLC FROM THE COAST OF MOROCCO NEAR 32N8W ALONG 27N27W TO 24N35W WITH A SURFACE TROUGH EXTENDING FROM 29N21W 26N25W TO 27N31W. THIS AREA IS UNDER FAIRLY DRY CONDITIONS ALOFT SO NO ASSOCIATED SHOWERS OR CONVECTION. AN UPPER HIGH IS IN THE TROPICAL ATLC NEAR 11N40W EXTENDING N OVER THE CENTRAL ATLC AND DOMINATING THE TROPICS W OF 30W N OF 15N. BROAD SURFACE RIDGE COVERS THE E AND CENTRAL ATLC ANCHORED BY A 1028 MB HIGH NEAR 33N39W GIVING THE REGION E OF 55W FAIR WEATHER. $$ HUFFMAN