NSSL and SPC answered with a bit more detail...
Cut and paste
Mr. Dodson,
Thank you for your recent inquiry concerning the experimental forecast graphics for the 2007 Spring Experiment. The forecasts your refer to are part of a multi-agency collaborative severe weather experiment being conducted in the NOAA Hazardous Weather Testbed that explores the operational utility of multiple convection-allowing WRF models including a 10 member ensemble. (See the HWT home page at http://hwt.nssl.noaa.gov/Spring_2007/ and click on the Operations Plan for more information about the experiment.) The experimental severe weather forecasts are a hybrid "outlook-watch" type product that cover a subset of the full US domain for a selected 6 hour period, and include probability contours similar to those used in SPC outlooks. The experimental forecasts are created utilizing operational and special experimental datasets as a way to explore the utility of experimental WRF modeling systems in a controlled (non-operational) severe weather forecast decision-making process. Note that these experimental forecasts are not available on the web until the next day so they cannot be perceived as being real-time, official SPC forecast products.
Let us know if you have any other questions.
Sincerely,
Steve Weiss
and
Hi Beau,
These are experimental short-term (6h) severe weather forecasts issued
on weekdays during this year's NOAA Hazardous Weather Testbed
Spring Experiment. The preliminary forecast is based on review of real-time
observational data and an assessment of high-resolution deterministic models
including the 4km WRF-NMM from NCEP, the 4km WRF-ARW from NSSL,
the 3km WRF-ARW from NCAR, and the 2km WRF from CAPS. This forecast
is then adjusted (to a final forecast) based on information contained in the
10 member 4km Storm Scale Ensemble Forecast (SSEF) system being produced
by CAPS. Note: these forecasts are entirely separate from SPC operational
forecasts and should not be considered official forecasts. In fact, these
forecasts are not even available on the web in real-time!
This is the first year of a 3-year program designed to evaluate the usefulness
in utilizing storm scale models in ensemble forecasting. The numerical "scores"
given to the preliminary and final forecasts are subjective and are arrived at
through consensus of the Spring Experiment participants. The higher the score,
the "better" the forecast. Monday through Thursday forecasts are evaluated the
following day, the Friday forecast is evaluated on Monday morning.
If you'd like more information, I encourage you to read the operations plan
that is posted on the Hazardous Weather Testbed Spring Experiment Website
here:
http://hwt.nssl.noaa.gov/Spring_2007/
Thank you for your interest!
Greg Carbin
National Weather Service
National Centers for Environmental Prediction
Storm Prediction Center
Norman, OK
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