The Eta lives on!

rdale

EF5
The WRF will still replace the Eta in the NAM slot, but Eta MOS will do the NGM thing and survive...

ATTENTION USERS OF THE MOS GUIDANCE:

EFFECTIVE JUNE 13 2006...BEGINNING WITH THE 1200 COORDINATED
UNIVERSAL TIME /UTC/ RUN...THE NWS WILL REPLACE THE FORECAST
MODEL CURRENTLY RUN IN THE NORTH AMERICAN MESOSCALE /NAM/ SYSTEM.
THE 12 KM HORIZONTAL RESOLUTION ETA MODEL IS CURRENTLY USED IN
THIS SYSTEM. THE MODEL WILL BE REPLACED WITH A 12 KM HORIZONTAL
RESOLUTION WEATHER RESEARCH AND FORECASTING /WRF/ VERSION OF THE
NON-HYDROSTATIC MESOSCALE MODEL /NMM/.

RECENT VERIFICATIONS INDICATE THAT THE CURRENT SYSTEM OF ETA-
BASED MODEL OUTPUT STATISTICS /MOS/ EQUATIONS...WHEN APPLIED TO
OUTPUT FROM THE WRF VERSION OF THE NMM...PRODUCES GUIDANCE THAT
IS CONSIDERABLY LESS ACCURATE THAN THE CURRENTLY OPERATIONAL ETA
MOS GUIDANCE.

TO ALLOW USERS TO TRANSITION TO MOS GUIDANCE BASED ON THE GLOBAL
FORECAST SYSTEM /GFS/... THE NWS WILL RUN AN INTERIM 32 KM ETA
MODEL OVER THE NAM DOMAIN DURING THE 0000 AND 1200 UTC FORECAST
CYCLES. FORECASTS FROM THIS ETA RUN WILL BE USED AS INPUT TO THE
ETA MOS. NO DIRECT MODEL OUTPUT FROM THIS INTERIM VERSION OF THE
ETA MODEL WILL BE TRANSMITTED OR MADE AVAILABLE ON NWS SERVERS.

THIS IMPLEMENTATION OF THE INTERIM ETA MODEL AND SUBSEQUENT
MODIFICATION TO THE ETA MOS GUIDANCE WILL OCCUR ON JUNE 13 2006
WHEN THE WRF IS IMPLEMENTED. NO DELAY IN THE TIME OF TRANSMISSION
OF THE ETA-BASED MOS PRODUCTS IS EXPECTED. THE QUALITY OF THE ETA
MOS GUIDANCE IN THIS RECONFIGURATION IS EXPECTED TO BE ABOUT THE
SAME AS THAT PRODUCED BY THE CURRENT ETA MOS SYSTEM.

THE EFFECTIVE DATE OF THIS CHANGE IS SOONER THAN SPECIFIED BY NWS
POLICY. REDUCING THE NORMAL ADVANCE LEAD TIME WAS APPROVED DUE TO
THE RECENT UNDERSTANDING OF THE NEGATIVE IMPACT THAT THE NCEP
MODEL CHANGE ON JUNE 13 2006 WOULD HAVE ON THE WRF MOS.

SAMPLE VERIFICATIONS CAN BE FOUND AT THE URL LISTED BELOW /USE
LOWER CASE LETTERS/:

HTTP://WWW.WEATHER.GOV/MDL/SYNOP/WRFMOSEVAL.HTM
 
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