000 WTPZ41 KNHC 291246 TCDEP1 TROPICAL DEPRESSION ONE-E SPECIAL DISCUSSION NUMBER 1 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP012010 500 AM PDT SAT MAY 29 2010 SATELLITE IMAGES AND MICROWAVE DATA THIS MORNING INDICATE THAT THE BROAD LOW PRESSURE SYSTEM SOUTHWEST OF GUATEMALA HAS DEVELOPED ENOUGH CONVECTIVE ORGANIZATION AND A WELL-DEFINED LOW-LEVEL CIRCULATION CENTER TO BE CLASSIFIED AS A TROPICAL DEPRESSION...THE FIRST OF THE 2010 EAST PACIFIC HURRICANE SEASON. THE INITIAL INTENSITY IS SET AT 30 KT...IN AGREEMENT WITH A 29/0323Z ASCAT OVERPASS...BUT THIS COULD BE A LITTLE CONSERVATIVE. THE INITIAL MOTION ESTIMATE IS 065/05 KT. THE CENTER HAS BECOME BETTER DEFINED IN BOTH ACTIVE AND PASSIVE MICROWAVE IMAGERY DURING THE PAST 6 HOURS...AND INFRARED IMAGERY INDICATES SMALL BANDING FEATURES BEGINNING TO DEVELOP AROUND THE CENTER DURING THE PAST COUPLE OF HOURS. THE CYCLONE IS EMBEDDED IN WEAK SOUTHWESTERLY FLOW ON THE WEST SIDE OF A LOW-LATITUDE RIDGE THAT EXTENDS WESTWARD ACROSS NORTHERN SOUTH AMERICA AND INTO SOUTHERN CENTRAL AMERICA. THIS STEERING PATTERN IS NOT EXPECTED TO CHANGE SIGNIFICANTLY AND AS A RESULT...THE OFFICIAL TRACK FORECAST CALLS FOR THE CYCLONE TO MOVE ON A SLOW NORTHEASTWARD OR EAST-NORTHEASTWARD COURSE... BRINGING THE CENTER NEAR THE COAST OF THE MEXICO/GUATEMALA BORDER IN 36 HOURS OR SO. HOWEVER...IT APPEARS THAT MOST OF THE ASSOCIATED WEATHER IS WELL AHEAD OF THE CENTER AND IS IN FACT ALREADY AFFECTING THE COAST. THIS TRACK IS SIMILAR TO BUT A LITTLE TO THE LEFT THE MODEL CONSENSUS...TVCN...DUE TO THE UNLIKELY SHARP EASTWARD TRACK INTO THE RIDGE AXIS FORECAST BY THE HWRF MODEL. THE AFOREMENTIONED ASCAT OVERPASS INDICATED A FEW 35-KT WIND VECTORS IN THE NORTHWESTERN QUADRANT...SUGGESTING THAT THIS CYCLONE MAY ALREADY BE NEAR TROPICAL STORM STRENGTH. THE SLOW-MOVING DEPRESSION IS EMBEDDED IN A WEAK VERTICAL WIND SHEAR ENVIRONMENT AND OVER 30C SSTS...WHICH WOULD SUGGEST THAT AT LEAST SOME MODEST STRENGTHENING SHOULD OCCUR. THE PROXIMITY TO MOUNTAINOUS TERRAIN MAY INHIBIT SIGNIFICANT INTENSIFICATION...BUT THIS TREND WILL BE MORE CLOSELY ASSESSED LATER TODAY AS ADDITIONAL SATELLITE INFORMATION BECOMES AVAILABLE. DUE TO THE SLOW FORWARD SPEED AND INTERACTION WITH HIGH TERRAIN... THE MAIN IMPACT FROM THIS SYSTEM SHOULD BE EXTREMELY HEAVY RAINFALL. THESE RAINS COULD PRODUCE LIFE-THREATENING FLASH FLOODS AND MUD SLIDES OVER SOUTHEASTERN MEXICO...GUATEMALA...EL SALVADOR...AND AS FAR INLAND AS HONDURAS. FORECAST POSITIONS AND MAX WINDS INITIAL 29/1200Z 12.9N 93.5W 30 KT 12HR VT 29/1800Z 13.0N 93.0W 40 KT 24HR VT 30/0600Z 13.3N 92.2W 50 KT 36HR VT 30/1800Z 13.7N 91.6W 50 KT 48HR VT 31/0600Z 14.4N 91.0W 35 KT...INLAND 72HR VT 01/0600Z 14.9N 91.2W 20 KT...DISSIPATING INLAND 96HR VT 02/0600Z...DISSIPATED $$ FORECASTER STEWART