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 ISIS


ZCZC MIATCDEP2 ALL
TTAA00 KNHC DDHHMM
TROPICAL STORM ISIS DISCUSSION NUMBER  20
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
8 PM PDT SUN SEP 12 2004

CONVECTION CONTINUES TO BURST ON THE PERIPHERY OF ISIS BUT AWAY FROM
THE LOW LEVEL CIRCULATION CENTER.  ISIS REMAINS SIGNIFICANTLY
SHEARED BUT IS STILL A 45 KT TROPICAL STORM...AS CLASSIFIED BY TAFB
AND AIR FORCE DVORAK ESTIMATES.  THE INITIAL MOTION HAS NOT CHANGED
AND REMAINS AT 270/8.

THE TRACK FORECAST IS ON TOP OF THE PREVIOUS TRACK FOR THE FIRST 24
HOURS.  THEREAFTER...MOST GUIDANCE ARE BUILDING IN A STRONG RIDGE
AHEAD OF THE FORECAST TRACK.  THIS WOULD WORK TO SLOW THE FORWARD
MOTION OF ISIS AND EVENTUALLY STEER THE STORM TO THE NORTHWEST OR
NORTH WHEN A TROUGH IS FORECAST TO BREAK DOWN THE RIDGE DURING DAYS
4 AND 5. ALL GUIDANCE EXCEPT UKMET SHOWS A NORTHWARD COMPONENT OF
MOTION AT THE 120 HOUR FORECAST PERIOD.  SLIGHT ADJUSTMENTS TO THE
FORECAST TRACK TOWARD THE NORTH ARE MADE TO ACCOUNT FOR THIS
SCENARIO...WHICH INCLUDES A CONTINUING TREND TOWARD A SLOWER
FORWARD SPEED.  THIS IS NOT A HIGH CONFIDENCE FORECAST BEYOND 72
HOURS.       

ALL INTENSITY GUIDANCE CONTINUES TO SUGGEST A GRADUAL STRENGTHENING
OF ISIS.  THIS IS CONTINGENT UPON A WEAKENING OF THE PERSISTENT
EASTERLY SHEAR THAT HAS BEEN AFFECTING ISIS SINCE ITS GENESIS.  THE
SHEAR PREDICTOR IN THE SHIPS MODEL SUGGESTS VERY LOW SHEAR
THROUGHOUT THE FORECAST PERIOD...BUT THE SHIPS FORECAST IS FOR ONLY
MODEST INTENSIFICATION.  IT SHOULD BE NOTED THAT THE GFS MODEL HAS
BEEN CONSISTENTLY UNDERESTIMATING THE SHEAR OVER ISIS FOR SEVERAL
DAYS NOW.  IF THE SHEAR DOES IN FACT SUBSIDE...GRADUAL
INTENSIFICATION SHOULD OCCUR AS THE THE SYSTEM BECOMES MORE COUPLED
IN THE VERTICAL.    
 
FORECASTER JARVINEN/HENNON
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      13/0300Z 17.4N 125.1W    45 KT
 12HR VT     13/1200Z 17.4N 126.5W    45 KT
 24HR VT     14/0000Z 17.4N 128.4W    50 KT
 36HR VT     14/1200Z 17.5N 129.9W    50 KT
 48HR VT     15/0000Z 17.6N 131.2W    55 KT
 72HR VT     16/0000Z 17.7N 132.7W    55 KT
 96HR VT     17/0000Z 17.9N 133.5W    55 KT
120HR VT     18/0000Z 18.1N 134.2W    55 KT
 
 
$$
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, 13-Sep-2004 02:44:51 UTC