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 DARBY


ZCZC MIATCDEP5 ALL
TTAA00 KNHC DDHHMM
TROPICAL STORM DARBY DISCUSSION NUMBER   3
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2 AM PDT TUE JUL 27 2004
 
TROPICAL STORM DARBY HAS BECOME MUCH BETTER ORGANIZED DURING THE
PAST 6 HOURS AND HAS DEVELOPED A CENTRAL DENSE OVERCAST...OR CDO...
FEATURE. THE LOW-LEVEL CENTER APPEARS TO BE EMBEDDED IN THE MIDDLE
OF THE CDO AND UPPER-LEVEL OUTFLOW HAS ALSO IMPROVED AND BECOME
MORE CIRCULAR. THE INITIAL INTENSITY OF 45 KT IS BASED ON A BLEND
OF DVORAK SATELLITE INTENSITY ESTIMATES OF 55 KT...45 KT...AND 30
KT FROM SAB...TAFB...AND AFWA...RESPECTIVELY.
 
THE INITIAL MOTION ESTIMATE REMAINS 280/12. THE OVERALL CONVECTIVE
CLOUD PATTERN HAS BEEN TRANSLATING A LITTLE NORTH OF DUE WEST THE
PAST 24 HOURS. IRONICALLY...THE DYNAMICAL MODELS HAVE ALL TAKEN
DARBY OFF TO THE NORTHWEST FROM ITS INITIAL POSITIONS DURING THE
SAME TIME FRAME. THE GFS...NOGAPS...AND THE GFDL MODELS HAVE BEEN
THE WORSE AND HAVE HAD A 30 DEGREE RIGHT-OF-TRACK BIAS OVER THE
LAST FEW MODEL RUNS. THE UKMET HAS HAD ONLY A SLIGHTLY LESS RIGHT
BIAS. THIS APPEARS TO BE DUE TO THE GLOBAL MODELS HAVING POORLY
INITIALIZED AN ALLEGED WEAKNESS IN THE SUBTROPICAL RIDGE TO THE
NORTH OF DARBY. WATER VAPOR IMAGERY AND THE LATEST UW-CIMSS WATER
VAPOR WIND ANALYSES INDICATE THE MID- TO UPPER-LEVEL FLOW NORTHWEST
THROUGH NORTHEAST OF DARBY IS WESTERLY AT 10-15 KT. IN ADDITION...
WATER VAPOR IMAGERY INDICATES THE UPPER-LEVEL LOW THAT HAD BEEN
LOCATED ABOUT 500 NMI NORTH-NORTHWEST OF THE DARBY HAS BEEN MOVING
RAPIDLY NORTHWESTWARD AWAY FROM THE CYCLONE...WHICH HAS LIKELY
RESULTED IN THE ELIMINATION OF THE WEAKNESS IN THE SUBTROPICAL
RIDGE. AS A RESULT...THE OFFICIAL FORECAST TRACK IS A LITTLE SOUTH
OF THE PREVIOUS FORECAST TRACK AND IS CLOSE TO A BLEND OF THE
STATISTICAL-DYNAMICAL MODEL...P91E...AND THE MEDIUM AND DEEP BAM.

SATELLITE IMAGERY INDICATES THAT DARBY IS REALLY STARTING TO WIND UP
A TIGHT CONVECTIVE BAND...SO A PERIOD OF RAPID INTENSIFICATION IS
FORECAST FOR THE NEXT 24 HOURS OR SO. THIS IS SUPPORTED BY DARBY 
FORECAST TO REMAIN IN A VERY FAVORABLE UPPER-LEVEL FLOW REGIME WITH
VERTICAL SHEAR GRADUALLY DECREASING TO LESS THAN 5 KT BY 36 HOURS.
THE ONLY HINDERING INFLUENCE APPEARS TO BE THE COOLER WATER THAT
DARBY WILL BE PASSING OVER AFTER 72 HOURS...AND THIS IS REFLECTED
BY A WEAKENING FORECAST AT 96 AND 120 HOURS. HOWEVER...IF AN EYE
DEVELOPS DURING THE NEXT 6-12 HOURS...THEN RAPID STRENGTHENING
COULD LAST LONGER THAN CURRENTLY FORECAST AND DARBY COULD BECOME A
MAJOR HURRICANE BY 36-48 HOURS WHILE STILL OVER 27-28C SSTS.
 
FORECASTER STEWART
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      27/0900Z 12.8N 117.3W    45 KT
 12HR VT     27/1800Z 13.2N 118.9W    60 KT
 24HR VT     28/0600Z 13.8N 120.9W    70 KT
 36HR VT     28/1800Z 14.3N 122.8W    80 KT
 48HR VT     29/0600Z 14.8N 124.9W    85 KT
 72HR VT     30/0600Z 15.5N 128.7W    85 KT
 96HR VT     31/0600Z 16.0N 132.5W    80 KT
120HR VT     01/0600Z 16.5N 137.0W    75 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 USA
nhcwebmaster@noaa.gov
Disclaimer
Credits
Information Quality
Glossary
Privacy Policy
Freedom of Information Act (FOIA)
About Us
Career Opportunities
Page last modified: Tuesday, 27-Jul-2004 08:42:26 UTC