ZCZC MIATCDEP4 ALL TTAA00 KNHC DDHHMM TROPICAL DEPRESSION FOUR-E DISCUSSION NUMBER 3 NWS NATIONAL HURRICANE CENTER MIAMI FL EP042012 200 PM PDT WED JUL 04 2012 THE DEPRESSION HAS CHANGED LITTLE DURING THE PAST SIX HOURS. HOWEVER...THERE ARE SIGNS NOW THAT THE NORTHERLY VERTICAL SHEAR IS BEGINNING TO ABATE AS MODEST CONVECTION HAS RECENTLY BEGUN TO DEVELOP IN THE NORTHERN SEMICIRCLE WITH A SMALL BURST OF CONVECTION ALSO HAVING DEVELOPED NEAR THE CENTER. THE LOW-LEVEL CENTER IS STILL DIFFICULT TO DETERMINE...BUT A FORTUITOUS 1628Z ASCAT OVERPASS INDICATED THE CENTER OF THE ELONGATED CIRCULATION WAS LOCATED VERY NEAR THE PREVIOUS FORECAST TRACK. ALTHOUGH SATELLITE INTENSITY ESTIMATES ARE A CONSENSUS T2.5/35 KT FROM TAFB AND SAB...AND T2.4/34 KT FROM UW-CIMSS ADT...THE INITIAL INTENSITY IS BEING MAINTAINED AT 30 KT BASED ON THE RECENT ASCAT DATA THAT ONLY SHOWED 25-KT WINDS IN THE NORTHEAST QUADRANT. EVEN ALLOWING FOR THE LOW BIAS OF ASCAT...THE SURFACE WINDS SHOULD BE NO MORE THAN 30 KT. THE INITIAL MOTION ESTIMATE IS 295/11 KT. THE CYCLONE IS EXPECTED TO GRADUALLY TURN MORE WESTWARD OVER THE NEXT 2 DAYS AS THE SYSTEM MOVES ALONG THE SOUTHERN PERIPHERY OF A DEEP-LAYER SUBTROPICAL RIDGE TO ITS NORTH. NHC MODEL GUIDANCE REMAINS IN EXCELLENT AGREEMENT ON THIS DEVELOPING TRACK SCENARIO. THE OFFICIAL FORECAST TRACK IS SITUATED IN THE MIDDLE OF THE TIGHTLY PACKED GUIDANCE ENVELOPE AND LIES CLOSE TO THE CONSENSUS MODELS TVCN AND TV15. MODERATE NORTHERLY TO NORTHEASTERLY VERTICAL WIND SHEAR THAT HAS BEEN HINDERING DEVELOPMENT OVER THE PAST COUPLE OF DAYS IS FORECAST BY ALL OF THE GLOBAL AND REGIONAL MODELS TO GRADUALLY SUBSIDE...AND AFTER 24 HOURS THE SHEAR IS EXPECTED TO BE LESS THAN 10 KT. THIS SHOULD ALLOW FOR AT LEAST MODEST STRENGTHENING THROUGH 72 HOURS WHILE THE CYCLONE REMAINS OVER WARM SSTS AND IN MOIST MID-LEVEL CONDITIONS. HOWEVER...BY 96 HOURS AND BEYOND...THE SYSTEM IS FORECAST TO MOVE OVER SUB-25C SSTS AND INTO A MORE STABLE THERMODYNAMIC ENVIRONMENT...WHICH SHOULD INDUCE STEADY WEAKENING. THE OFFICIAL INTENSITY FORECAST IS SIMILAR TO THE PREVIOUS ADVISORY AND REMAINS ABOVE THE STATISTICAL GUIDANCE AND CLOSE TO A BLEND OF THE HWRF AND GFS MODELS...WHICH INDICATE A HURRICANE BY 72 HOURS. FORECAST POSITIONS AND MAX WINDS INIT 04/2100Z 13.5N 107.8W 30 KT 35 MPH 12H 05/0600Z 14.0N 109.3W 35 KT 40 MPH 24H 05/1800Z 14.5N 111.3W 40 KT 45 MPH 36H 06/0600Z 14.8N 113.3W 45 KT 50 MPH 48H 06/1800Z 14.9N 115.4W 55 KT 65 MPH 72H 07/1800Z 15.0N 119.4W 65 KT 75 MPH 96H 08/1800Z 15.3N 123.7W 55 KT 65 MPH 120H 09/1800Z 16.1N 128.4W 45 KT 50 MPH $$ FORECASTER STEWART NNNN
Alternate Formats
About Alternates -
E-Mail Advisories -
RSS Feeds
Cyclone Forecasts
Latest Advisory -
Past Advisories -
About Advisories
Marine Forecasts
Latest Products -
About Marine Products
Tools & Data
Satellite Imagery -
US Weather Radar -
Aircraft Recon -
Local Data Archive -
Forecast Verification -
Deadliest/Costliest/Most Intense
Learn About Hurricanes
Storm Names
Wind Scale -
Prepare -
Climatology -
NHC Glossary -
NHC Acronyms -
Frequently Asked Questions -
AOML Hurricane-Research Division
About Us
About NHC -
Mission/Vision -
Other NCEP Centers -
NHC Staff -
Visitor Information -
NHC Library
NOAA/
National Weather Service
National Centers for Environmental Prediction
National Hurricane Center
11691 SW 17th Street
Miami, Florida, 33165-2149 USA
nhcwebmaster@noaa.gov
Disclaimer
Privacy Policy
Credits
About Us
Glossary
Career Opportunities
Page last modified: Monday, 31-Dec-2012 12:10:14 UTC