je.st
news
Tropical Storm DALILA Forecast Discussion Number 5
2013-07-01 04:32:49| National Hurricane Center (East Pacific)
Issued at 800 PM PDT SUN JUN 30 2013 000 WTPZ44 KNHC 010232 TCDEP4 TROPICAL STORM DALILA DISCUSSION NUMBER 5 NWS NATIONAL HURRICANE CENTER MIAMI FL EP042013 800 PM PDT SUN JUN 30 2013 DURING THE PAST 6 HOURS...VISIBLE AND MICROWAVE SATELLITE IMAGERY INDICATES THAT THE INNER CORE STRUCTURE OF DALILA HAS IMPROVED. IN FACT...37 GHZ AND RADAR IMAGERY FROM A 30/1857Z TRMM OVERPASS REVEALED THAT A 70 PERCENT CLOSED LOW- TO MID-LEVEL EYEWALL HAD DEVELOPED. UPPER-LEVEL OUTFLOW HAS ALSO IMPROVED...ESPECIALLY IN THE NORTHWESTERN SEMICIRCLE. THE INITIAL INTENSITY OF 40 KT IS BASED ON A BLEND OF 45 KT...30 KT...AND 47 KT FROM TAFB...SAB... AND UW-CIMSS ADT...RESPECTIVELY. MICROWAVE AND VISIBLE SATELLITE FIXES SUGGEST THAT DALILA HAS BEEN WOBBLING ABOUT A MEAN MOTION OF 315/09 KT. THE MASSIVE HEAT WAVE RIDGE OVER THE SOUTHWESTERN U.S. EXTENDS SOUTHWARD INTO NORTHERN AND CENTRAL MEXICO...AND ALSO WESTWARD ACROSS BAJA CALIFORNIA. THIS STAGNANT STEERING PATTERN SHOULD KEEP DALILA MOVING NORTHWESTWARD TONIGHT...FOLLOWED BY A GRADUAL TURN TOWARD THE WEST-NORTHWEST LATE MONDAY AND TO THE WEST BY TUESDAY. THERE IS A LARGE SPREAD IN THE MODEL GUIDANCE...WITH THE ECMWF AND HWRF MODELS TAKING DALILA SOUTHWESTWARD BY 72 HOURS AS THE CYCLONE WEAKENS. HOWEVER...THE GFS AND GFS ENSEMBLE MEAN MODELS...WHICH HAVE BEEN FAIRLY STABLE THE PAST FEW CYCLES...KEEP DALILA MOVING IN A GENERAL WESTWARD DIRECTION LATE IN THE PERIOD AS A ROBUST TROPICAL STORM OR HURRICANE...AND THAT TRACK SCENARIO WAS CLOSELY FOLLOWED. ALTHOUGH THE VERTICAL SHEAR IS CURRENTLY LIGHT AT ONLY 3 KT...THE SHIPS INTENSITY MODEL INDICATES THAT THE SHEAR DIRECTION IS FROM A SOUTH-SOUTHEASTERLY DIRECTION. THE COMBINATION OF THE SHEAR AND SOME DRY AIR ENTRAINMENT INTO THE EASTERN SEMICIRCLE OF THE CYCLONE HAS KEPT MOST OF THE SIGNIFICANT DEEP CONVECTION DISPLACED TO THE NORTHWEST OF THE CENTER. HOWEVER...RECENT VISIBLE AND INFRARED IMAGERY INDICATE THAT MORE INNER CORE CONVECTION HAS BEGUN TO DEVELOP AROUND THE AFOREMENTIONED MICROWAVE EYE FEATURE...WHICH COULD BE A SIGNAL THAT AT LEAST SOME GRADUAL INTENSIFICATION SHOULD OCCUR DURING THE NEXT 48 HOURS BEFORE STRONGER SHEAR KICKS IN. DALILA IS A COMPACT TROPICAL CYCLONE...WHICH MEANS THAT IT IS SUSCEPTIBLE TO RAPID CHANGES CHANGES IN INTENSITY...BOTH UP AND DOWN. SO FOR NOW...A CONSERVATIVE FORECAST IS THE BEST COURSE OF ACTION UNTIL A SOLID INTENSIFICATION SIGNAL HAS BEEN ESTABLISHED. THE OFFICIAL INTENSITY FORECAST IS ONLY SLIGHTLY HIGHER THAN THE PREVIOUS ADVISORY...AND NOW SHOWS DALILA REACHING HURRICANE STRENGTH BY 48 HOURS...WHICH IS SLIGHTLY HIGHER THAN ALL OF THE NHC INTENSITY GUIDANCE. FORECAST POSITIONS AND MAX WINDS INIT 01/0300Z 16.8N 104.4W 40 KT 45 MPH 12H 01/1200Z 17.5N 105.3W 45 KT 50 MPH 24H 02/0000Z 18.3N 106.3W 55 KT 65 MPH 36H 02/1200Z 18.7N 107.1W 60 KT 70 MPH 48H 03/0000Z 18.9N 107.7W 65 KT 75 MPH 72H 04/0000Z 19.0N 109.0W 55 KT 65 MPH 96H 05/0000Z 19.0N 110.6W 50 KT 60 MPH 120H 06/0000Z 19.0N 113.0W 40 KT 45 MPH $$ FORECASTER STEWART
Tags: number
discussion
storm
tropical
Category:Transportation and Logistics
Latest from this category |
All news |
||||||||||||||||||
|
|||||||||||||||||||