Skip Navigation Links weather.gov   
NOAA logo - Click to go to the NOAA homepage National Weather Service   NWS logo - Click to go to the NWS homepage
National Hurricane Center
Local forecast by
"City, St" or "ZIP"

 
Alternate Formats
   Text     |   Mobile
   Email   |   RSS XML/RSS logo
   About Alternates
Cyclone Forecasts
   Latest Advisory
   Past Advisories
   Audio/Podcasts
   About Advisories
Marine Forecasts
   Atlantic & E Pacific
   Gridded Marine
   About Marine
Tools & Data
   Satellite | Radar
   Analysis Tools
   Aircraft Recon
   GIS Datasets
   Data Archive
Development
   Experimental
   Research
   Forecast Accuracy
Outreach & Education
   Prepare
   Storm Surge
   About Cyclones
   Cyclone Names
   Wind Scale
   Most Extreme
   Forecast Models
   Breakpoints
   Resources
   Glossary | Acronyms
   Frequent Questions
Our Organization
   About NHC
   Mission & Vision
   Staff | Q&A
   Visitors | Virtual Tour
   Library Branch
   NCEP | Newsletter
Contact Us
   Comments
Follow the National Hurricane Center on Facebook Follow the National Hurricane Center on Twitter
Subscribe the National Hurricane Center on YouTube Read the National Hurricane Center Inside the Eye blog on WordPress
FirstGov.gov is the U.S. Government's official Web portal to all Federal, state and local government Web resources and services.
 
 

Tropical Storm ISAAC


ZCZC MIATCDAT4 ALL
TTAA00 KNHC DDHHMM
 
TROPICAL STORM ISAAC DISCUSSION NUMBER  13
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL092012
500 AM EDT FRI AUG 24 2012
 
DATA FROM THE HURRICANE HUNTER AIRCRAFT INDICATE THAT ISAAC REMAINS
POORLY ORGANIZED. WHILE THE 850-MB FLIGHT LEVEL CENTER WAS WELL
SOUTH OF THE PREVIOUSLY ESTIMATED SURFACE CENTER LOCATION...
DROPSONDE DATA SUGGEST THAT THE SURFACE CENTER REMAINS FARTHER
NORTH. FLIGHT LEVEL AND SFMR WINDS SUPPORT MAINTAINING THE
INTENSITY AT 40 KT FOR THIS ADVISORY...WHILE THE AIRCRAFT FOUND A
MINIMUM PRESSURE OF 1000 MB. GIVEN THE CURRENT LACK OF ORGANIZATION
OF THE INNER CORE...ONLY LIMITED STRENGTHENING IS FORECAST BEFORE
THE CYCLONE BEGINS TO INTERACT WITH HISPANIOLA IN THE NEXT 24
HOURS. AFTER THAT TIME LITTLE CHANGE IS FORECAST AS ISAAC INTERACTS
WITH PORTIONS OF CUBA. LATER IN THE PERIOD...ISAAC SHOULD HAVE AN
OPPORTUNITY TO STRENGTHEN OVER THE STRAITS OF FLORIDA AND THE GULF
OF MEXICO...AND THE NHC FORECAST IS CLOSE TO THE LGEM MODEL AT DAYS
4 AND 5. IT SHOULD BE NOTED THAT THERE IS SIGNIFICANT UNCERTAINTY
IN TROPICAL CYCLONE INTENSITY PREDICTIONS AT 3 TO 5 DAYS.
 
THE LONG TERM INITIAL MOTION ESTIMATE IS A HIGHLY UNCERTAIN
275/13...AS THE INITIAL POSITION ESTIMATE IS BASED ON A BLEND OF
RECENT FIXES AND CONTINUITY. THE TRACK MODEL GUIDANCE CONTINUES TO
BE IN GENERALLY GOOD AGREEMENT ON THE RESUMPTION OF A WEST-
NORTHWESTWARD AND THEN NORTHWESTWARD MOTION IN THE NEXT 24 HOURS AS
THE SUBTROPICAL RIDGE NORTH OF ISAAC WEAKENS. THIS GENERAL MOTION
SHOULD CONTINUE THROUGH DAY 4...WHEN A TURN MORE TOWARD THE NORTH
IS SHOWN AS A SHORTWAVE TROUGH AMPLIFIES OVER THE MISSISSIPPI
VALLEY. LATE IN THE PERIOD THE TRACK MODEL GUIDANCE IS IN BETTER
AGREEMENT ON THIS SCENARIO...AS THE ECMWF HAS TRENDED EASTWARD
TOWARD THE REST OF THE MODELS THIS CYCLE. THE NEW NHC FORECAST HAS
BEEN ADJUSTED ABOUT A DEGREE SOUTHWARD IN THE FIRST 12 HOURS DUE TO
THE INITIAL POSITION AND MOTION...AND IS THEN BLENDED BACK TOWARD
THE PREVIOUS TRACK BY 48 HOURS. AFTER THAT TIME...THE NHC FORECAST
IS ESSENTIALLY AN UPDATE OF THE PREVIOUS ONE...AND IS BETWEEN THE
ECMWF ON THE LEFT AND THE GFS AND TVCA CONSENSUS ON THE RIGHT. 
 
IT IS IMPORTANT NOT TO FOCUS ON THE EXACT TRACK DUE TO UNCERTAINTIES
IN THE INITIAL LOCATION AND THE TRACK FORECAST...AND THE FACT THAT
ISAAC HAS A LARGE AREA OF TROPICAL STORM FORCE WINDS ASSOCIATED
WITH IT. 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  24/0900Z 16.1N  70.0W   40 KT  45 MPH
 12H  24/1800Z 17.0N  71.9W   50 KT  60 MPH
 24H  25/0600Z 18.8N  74.1W   45 KT  50 MPH
 36H  25/1800Z 20.6N  76.7W   45 KT  50 MPH...INLAND
 48H  26/0600Z 22.4N  78.9W   45 KT  50 MPH...OVER WATER
 72H  27/0600Z 25.0N  82.5W   55 KT  65 MPH
 96H  28/0600Z 28.0N  86.0W   65 KT  75 MPH
120H  29/0600Z 30.5N  87.5W   75 KT  85 MPH...INLAND
 
$$
FORECASTER BRENNAN
 
NNNN


Quick Navigation Links:
Tropical Cyclone Forecasts  -  Tropical Marine Forecasts  -  Data Archive
Outreach  -  Prepare  -  About Cyclones  -  About NHC  -  Contact Us

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
Credits
Information Quality
Glossary
Privacy Policy
Freedom of Information Act (FOIA)
About Us
Career Opportunities
Page last modified: Monday, 31-Dec-2012 12:09:26 UTC