000 AXNT20 KNHC 010001 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...SPECIAL FEATURE... TROPICAL STORM ARTHUR IS CENTERED NEAR 18.4N 88.9W OR ABOUT 75 MILES NW OF BELIZE CITY AT 31/2100 UTC MOVING WNW 6 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. THE STORM CENTER IS INLAND HOWEVER BANDS OF CONVECTION ARE OVER THE NW CARIBBEAN SEA. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS FROM 16N-20N BETWEEN 85W-93W...AND FROM 18N-21N BETWEEN 81W-83W. ARTHUR MAY WEAKEN SLIGHTLY OVER LAND BUT IS FORECAST TO MOVE TO THE SRN BAY OF CAMPECHE WHERE IT MAY RETAIN TROPICAL STORM STATUS. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 20W 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. WIDELY SCATTERED MODERATE CONVECTION IS CONFINED TO THE ITCZ. TROPICAL WAVE IS ALONG 44W/45W S OF 15N MOVING W 10-15 KT. MIMIC-TPW SHOWS A WELL-DEFINED WAVE AXIS WITH A BROAD SIGNATURE ON SATELLITE IMAGERY. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE WITHIN FROM 7N-9N BETWEEN 44W-50W...AND FROM EQ-2N BETWEEN 39W-44W. TROPICAL WAVE IS ALONG 58W S OF 12N MOVING W NEAR 15 KT. THIS LOW AMPLITUDE WAVE HAS A WELL-DEFINED INVERTED-V SATELLITE SIGNATURE. SCATTERED MODERATE CONVECTION IS WITHIN 200 NM OF THE WAVE AXIS FROM 2N-7N. TROPICAL WAVE IN THE W CARIBBEAN IS ALONG 83W S OF 21N MOVING W 10-15 KT. 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 IS NOTED. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 10N15W 1N33W 2N45W AND INTO NE BRAZIL NEAR 1N50W. SCATTERED MODERATE CONVECTION IS FROM 2N-4N BETWEEN 15W-17W. SIMILAR CONVECTION IS FROM 2N-5N BETWEEN 22W-28W. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS FROM 2N-4N BETWEEN 37W-39W...AND FROM EQ-7N BETWEEN 54W-57W. ...DISCUSSION... GULF OF MEXICO... WEAK SURFACE RIDGING IS OVER THE NRN GULF OF MEXICO N OF 25N WITH MOSTLY FAIR WEATHER AND ELY TO SELY 10-15 KT WINDS. SCATTERED MODERATE CONVECTION IS INLAND HOWEVER OVER SW FLORIDA FROM 25N-27N. BROAD CYCLONIC TURNING COVERS THE SRN GULF DUE TO THE NRN PERIPHERY OF T.S. ARTHUR. AN AREA OF SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS OVER THE SW BAY OF CAMPECHE FROM 18N-20N BETWEEN 90W-93W. IN THE UPPER LEVELS...AN UPPER LEVEL HIGH IS OVER THE SW BAY OF CAMPECHE NEAR 19N96W. NWLY UPPER LEVEL FLOW COVERS MUCH OF THE REMAINDER OF THE GULF OF MEXICO. STRONG SUBSIDENCE LIES N OF 22N WHILE SIGNIFICANT UPPER MOISTURE IS S OF 22N DUE TO ARTHUR. ARTHUR WILL MOVE INTO THE SW BAY OF CAMPECHE WITHIN 24 HOURS WITH CONVECTION. CARIBBEAN... ARTHUR IS INLAND OVER THE YUCATAN PENINSULA. SEE ABOVE. A TROPICAL WAVE IS ALSO OVER THE WRN CARIBBEAN W OF THE CAYMAN ISLANDS. PATCHES OF SCATTERED MODERATE CONVECTION EXTEND FROM PUERTO RICO TO W CUBA N OF 18N. IN THE UPPER LEVELS...RIDGING IS PRODUCING MOSTLY NWLY UPPER LEVEL FLOW OVER THE CENTRAL AND E CARIBBEAN E OF 80W. SIGNIFICANT UPPER LEVEL MOISTURE IS N OF 13N. EXPECT CONTINUED CONVECTION W OF 80W DUE TO ARTHUR OVER THE NEXT 24 HOURS. ATLANTIC... A LARGE 1028 MB HIGH IS CENTERED OVER THE CENTRAL ATLANTIC NEAR 35N42W DOMINATING MOST OF THE ATLANTIC. AN EMBEDDED WEAK SURFACE TROUGH IS OVER THE W ATLANTIC ALONG 31N60W 26N65W. ISOLATED MODERATE CONVECTION IS FROM 25N-29N BETWEEN 59W-61W. IN THE UPPER LEVELS...A RIDGE IS N OF 20N AND W OF 70W. A TROUGH IS OVER THE W ATLANTIC N OF 20N BETWEEN 55W-70W. AN EMBEDDED UPPER LEVEL LOW IS CENTERED NEAR 24N63W. A RIDGE IS N OF 20N BETWEEN 25W-55W. AN UPPER LEVEL HIGH IS CENTERED OVER THE TROPICAL ATLANTIC NEAR 10N40W. ANOTHER UPPER LEVEL HIGH IS CENTERED ALONG THE COAST OF W AFRICA NEAR 11N16W. $$ FORMOSA