000 WTNT43 KNHC 151440 TCDAT3 TROPICAL STORM KARL DISCUSSION NUMBER 4 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL132010 1000 AM CDT WED SEP 15 2010 THE CENTER OF KARL MADE LANDFALL ALONG THE SOUTHEASTERN COAST OF THE YUCATAN PENINSULA OF MEXICO AT ABOUT 1245 UTC. BEFORE LANDFALL... AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT REPORTED A CENTRAL PRESSURE NEAR 991 MB WITH 850 MB FLIGHT-LEVEL WINDS OF 61 KT JUST NORTH OF THE CENTER. THE MAXIMUM RELIABLE SFMR WINDS WERE 50-55 KT. BASED ON THIS...THE LANDFALL INTENSITY IS ESTIMATED AT 55 KT. DATA FROM THE RADAR IN BELIZE CITY SHOWED THAT KARL WAS DEVELOPING AN EYE AT LANDFALL...BUT AT THIS TIME THERE IS NO OTHER EVIDENCE TO SUGGEST IT REACHED HURRICANE STRENGTH AFTER THE HURRICANE HUNTER DEPARTED. KARL HAS BEEN MOVING A BIT TO THE LEFT OF THE PREVIOUS FORECASTS... WITH THE INITIAL MOTION NOW 280/12. KARL REMAINS ON THE SOUTH SIDE OF A LOW-/MID-LEVEL RIDGE CENTERED OVER THE NORTHERN GULF COAST...AND THIS FEATURE SHOULD STEER THE CYCLONE GENERALLY WEST-NORTHWESTWARD OR WESTWARD ACROSS THE SOUTHWESTERN GULF OF MEXICO INTO MAINLAND MEXICO. THERE IS SOME SPREAD IN THE GUIDANCE...WITH THE GFS...GFDL...AND HWRF MODELS SHOWING A MORE NORTHWARD MOTION THAN THE ECMWF...UKMET...CANADIAN...AND NOGAPS MODELS. THE NEW TRACK FORECAST WILL SPLIT THE DIFFERENCE BETWEEN THE TWO MODEL CAMPS AND LIE JUST TO THE SOUTH OF THE CONSENSUS MODELS. THE NEW TRACK IS SHIFTED A LITTLE TO THE SOUTH OF THE PREVIOUS TRACK FOR THE FIRST 48 HR. KARL SHOULD WEAKEN TO A TROPICAL DEPRESSION BY THE TIME IT REACHES THE WEST COAST OF THE YUCATAN PENINSULA. ONCE THE CENTER REACHES WATER...THE COMBINATION OF WARM SEA SURFACE TEMPERATURES AND LIGHT VERTICAL WIND SHEAR SHOULD ALLOW RE-INTENSIFICATION AS FORECAST BY ALL GUIDANCE. THE NEW INTENSITY FORECAST IS SIMILAR TO THE PREVIOUS FORECAST...CALLING FOR KARL TO BECOME A HURRICANE BEFORE MAKING LANDFALL IN MAINLAND MEXICO. KARL SHOULD WEAKEN AFTER ITS SECOND LANDFALL AND DISSIPATED OVER THE MOUNTAINS OF CENTRAL MEXICO BY 120 HR. FORECAST POSITIONS AND MAX WINDS INITIAL 15/1500Z 18.6N 88.2W 50 KT...INLAND 12HR VT 16/0000Z 19.1N 89.7W 35 KT...INLAND 24HR VT 16/1200Z 20.1N 91.7W 30 KT...OVER WATER 36HR VT 17/0000Z 20.9N 93.7W 45 KT 48HR VT 17/1200Z 21.3N 95.2W 60 KT 72HR VT 18/1200Z 21.5N 98.0W 75 KT...INLAND 96HR VT 19/1200Z 21.0N 101.0W 25 KT...INLAND 120HR VT 20/1200Z...DISSIPATED $$ FORECASTER BEVEN