Skip Navigation Links   
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
   About Advisories
Marine Forecasts
   Atlantic & E Pacific
   Gridded Marine
   About Marine
Tools & Data
   Satellite | Radar
   Analysis Tools
   Aircraft Recon
   GIS Datasets
   Data Archive
   Forecast Accuracy
Outreach & Education
   Storm Surge
   About Cyclones
   Cyclone Names
   Wind Scale
   Most Extreme
   Forecast Models
   Glossary | Acronyms
   Frequent Questions
Our Organization
   About NHC
   Mission & Vision
   Staff | Q&A
   Visitors | Virtual Tour
   Library Branch
   NCEP | Newsletter
Contact Us
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 is the U.S. Government's official Web portal to all Federal, state and local government Web resources and services.

Tropical Storm HERNAN


200 AM PDT SUN JUL 27 2014

Conventional satellite imagery and scatterometer wind data indicate
that Hernan has continued to strengthen. A small central dense
overcast has persisted over the center during the past 6 hours, and
0418 UTC and 0510 UTC ASCAT-A and ASCAT-B overpasses indicated
surface winds of 48 kt and 51 kt, respectively, were present just
east of center. Assuming that the coarse resolution ASCAT data has
under-sampled the rather small and tight inner core wind field, the
initial intensity has been increased to 55 kt. This intensity is
supported by satellite intensity estimates of 55 kt from TAFB and 56
kt from UW-CIMSS ADT.

The initial motion estimate is northwestward or 310/12 kt. Hernan is
being steered along the southwestern periphery of a strong
subtropical ridge located across the southwestern and southern
United States. This persistent steering pattern is expected to
keep Hernan moving in a general northwestward direction for the
next 2-3 days, followed by a turn toward the west when the cyclone
weakens and is steered primarily the by low-level easterly trade
wind flow.  Although the models have again shifted slightly
northward, the new NHC track forecast is just an update of the
previous advisory track and lies along the southern edge of the
guidance envelope due to the expected quicker weakening than what
the more northerly track GFS and GFDL models are forecasting.

Hernan has strengthened 20 kt in the past 12 hours, which is a
faster-than-normal rate of intensification. The cyclone has about
another 12 hours or so of favorable conditions that could allow
Hernan to achieve hurricane strength. After that, however,
increasing westerly vertical wind shear should induce at least
some weakening until around 48 hours, at which time more rapid
weakening is expected as the the system moves over sub-25C SSTs.
By Days 4 and 5, decreasing sea surface temperatures and even
stronger shear should cause Hernan to degenerate into a remnant low
pressure system.


INIT  27/0900Z 16.9N 110.0W   55 KT  65 MPH
 12H  27/1800Z 18.1N 111.7W   65 KT  75 MPH
 24H  28/0600Z 19.6N 114.1W   60 KT  70 MPH
 36H  28/1800Z 21.0N 116.5W   55 KT  65 MPH
 48H  29/0600Z 22.1N 118.6W   45 KT  50 MPH
 72H  30/0600Z 23.3N 122.3W   30 KT  35 MPH
 96H  31/0600Z 23.6N 125.8W   25 KT  30 MPH...POST-TROP/REMNT LOW
120H  01/0600Z 23.6N 128.7W   20 KT  25 MPH...POST-TROP/REMNT LOW

Forecaster Stewart


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
Information Quality
Privacy Policy
Freedom of Information Act (FOIA)
About Us
Career Opportunities
Page last modified: Wednesday, 31-Dec-2014 12:09:34 UTC