000 WTNT41 KNHC 010853 TCDAT1 TROPICAL STORM ARTHUR DISCUSSION NUMBER 4 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL012008 500 AM EDT SUN JUN 01 2008 THE CENTER OF ARTHUR IS DIFFICULT TO LOCATE IN NIGHT-VIS IMAGERY...BUT STILL APPEARS TO BE SLOWLY CROSSING THE SOUTHERN YUCATAN PENINSULA. LATEST INFRARED SATELLITE IMAGERY INDICATES STRONG CONVECTIVE ACTIVITY OVER THE GULF OF HONDURAS...NORTHERN GUATEMALA...AND SOUTHEASTERN MEXICO...BUT NONE NEAR THE CIRCULATION CENTER. SINCE TROPICAL STORM CONDITIONS COULD STILL BE OCCURRING OVER THE GULF OF HONDURAS....ARTHUR WILL REMAIN A 35 KT TROPICAL STORM FOR THIS ADVISORY. THE INITIAL MOTION IS WEST AT 6 KT...AND WITH LOW- TO MID-LEVEL RIDGING IN THE GULF OF MEXICO EXPECTED TO PERSIST FOR THE NEXT COUPLE OF DAYS...A GENERAL WESTWARD MOTION SHOULD CONTINUE. ALL OF THE CURRENT GUIDANCE KEEPS THE CENTER OF ARTHUR INLAND OVER MEXICO...AND IS IN BETTER AGREEMENT THAN PREVIOUS RUNS. THE OFFICIAL TRACK FORECAST IS SIMILAR TO THE PREVIOUS ONE WITH A SLIGHT ADJUSTMENT TO THE SOUTH. WITH THE CENTER OF ARTHUR FORECAST TO REMAIN OVER LAND...MOST LIKELY THE BEST THAT IT CAN DO IS TO MAINTAIN STORM STRENGTH FOR A FEW MORE HOURS. THE OFFICIAL INTENSITY FORECAST CALLS FOR WEAKENING TO A DEPRESSION LATER TODAY...WITH DEGENERATION TO A REMNANT LOW EXPECTED IN TWO OR THREE DAYS. A POSSIBILITY STILL EXISTS THAT THE CENTER COULD EMERGE OVER THE SOUTHERN BAY OF CAMPECHE....ALTHOUGH NORTHERLY WIND SHEAR AND DRY AIR PARKED OVER THE GULF OF MEXICO WOULD LIMIT REDEVELOPMENT SHOULD THIS OCCUR. THE PRIMARY THREAT FROM ARTHUR REMAINS THE HEAVY RAINFALL ALONG WITH THE POTENTIAL FOR LIFE-THREATENING FLASH FLOODS AND MUDSLIDES. FORECAST POSITIONS AND MAX WINDS INITIAL 01/0900Z 18.3N 90.1W 35 KT 12HR VT 01/1800Z 18.2N 90.8W 30 KT...INLAND 24HR VT 02/0600Z 18.1N 91.9W 30 KT...INLAND 36HR VT 02/1800Z 18.0N 93.0W 30 KT...INLAND 48HR VT 03/0600Z 18.0N 94.0W 30 KT...INLAND 72HR VT 04/0600Z 18.0N 95.5W 25 KT...REMNANT LOW 96HR VT 05/0600Z...DISSIPATED $$ FORECASTER MAINELLI/FRANKLIN