20000217: Eta change to 60 hrs-ADMIN NOTICE NOUS40 KWBC (fwd)

• To: nws-changes@xxxxxxxxxxxxxxxx
• Subject: 20000217: Eta change to 60 hrs-ADMIN NOTICE NOUS40 KWBC (fwd)
• From: Linda Miller <lmiller@xxxxxxxxxxxxxxxx>
• Date: Thu, 17 Feb 2000 10:09:43 -0700

080 
NOUS40 KWBC 171648
FOS/NOAAPORT NOTICE NO. 1602     FEBRUARY 17... 2000
PART 3 OF A 3 PART MESSAGE

ATTENTION    FAMILY OF SERVICES SUBSCRIBERS
              NOAAPORT USERS

SUBJECT      NOTICE OF INTENT TO CHANGE EXTEND ETA TO 60
              HOURS + CHANGE PACKAGE


SPECIFIC EXAMPLES OF NOTE

OUR EXAMINATION OF THE RESULTS SUGGEST

1/ 60 HR EXTENSION S SKILL DOES NOT DROP SHARPLY FROM THE 48
HOUR LEVEL OF SKILL BUT THE TENDENCY OF THE ETA TO HAVE
WEAKER CYCLONE  DEVELOPMENT IS STILL PRESENT.  WE HOPE TO BE
ABLE TO TEST FIXES FOR THAT ASPECT IN NEAR FUTURE.

2/ SURFACE AND LOW LEVEL FIELDS LIKE TEMPERATURE... MOISTURE
AND WIND ALL BENEFIT FROM THE HIGHER RESOLUTION OUTPUT AS
DO FIELDS LIKE VORTICITY AND JET-STREAM MAXIMAS AT UPPER LEVELS.

3/ THE COASTAL BIAS IN THE SOUTHEAST US HAS BEEN REDUCED.
PRECIP MAY STILL APPEAR IN THE COASTAL AREA BUT THIS WILL
NOT BE THE EXCESSIVE AMOUNTS SEEN IN THE PAST.  SIMILARLY...
WE HAVE NOT SOLVED THE DIFFICULT PROBLEM OF CONVECTION OVER
COMPLEX ELEVATED TERRAIN... BUT THE CHANGES HAVE RESULTED IN
INCREASED FREQUENCY OF THE BMJ SCHEME TRIGGERING OVER THE
MOUNTAINS WHEREAS IT HARDLY EVER DID BEFORE.  THE IMPACT OF

4/ VAD

5/ BALLOON DRIFT WILL BE INCREMENTALLY POSITIVE.
END
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ANTICIPATED IMPACT ON FORECASTS

THE CONVECTIVE SCHEME CHANGES SHOULD IMPROVE THE
CREDIBILITY WITH WHICH THE MESO ETA PRECIP GUIDANCE IS
USED ALONG THE SE GULF   ATLANTIC COASTS AND THERE WILL
BE MORE CONVECTIVE EVENTS OCCURING IN THE MESO ETA OVER
THE HIGH TERRAIN.  OVERALL... WITH THE EXCEPTION OF THESE TWO
AREAS... THE CHANGES SHOULD NOT REQUIRE ANY CHANGE IN THE
WAY FORECASTERS TREAT OR INTERPRET THE MESO ETA GUIDANCE.

HUMAN POINTS OF CONTACT FOR FURTHER INFORMATION ON THE
CHANGES

GENERAL - GEOFF DIMEGO /301-763-8000 EXT 7221...
           GEOFF.DIMEGO/AT SYMBOL/NOAA.GOV/

CONVECTIVE - KEN MITCHELL /301-763-8000 EXT7225...

              KEN.MITCHELL/AT SYMBOL/NOAA.GOV/

PRODUCTS - GEOFF MANIKIN /301-763-8000 EXT7263...
            GEOFF.MANIKIN/AT SYMBOL/NOAA.GOV/

EXTENSION - ERIC ROGERS /301-763-8000 EXT7227...
             ERIC.ROGERS/AT SYMBOL/NOAA.GOV/

FIELD EVALUATION

EMC   OM ARE SOLICITING NWS REGIONAL FOCAL POINTS.


APPROVALS
NCEP DIRECTOR                        DATE

EMC DIRECTOR                         DATE

FUTURE CHANGES

REQUESTS FOR GUIDANCE TO COVER THE DAY 3 HAVE BEEN RECEIVED
AND WILL REQUIRE AN EXTENSION OF ANOTHER 24 HOURS FROM 60
TO 84.  DIRECT USE OF RADIANCES IN THE 3DVAR WILL BE TESTED
ALONGSIDE THE USE OF OBSERVED PRECIPITATION AND CLOUD IN
THE EDAS AND THE HIGHER RESOLUTION TESTS TARGETTED AT 22 KM
AND 50 LEVELS FOR AN AUGUST 2000 IMPLEMENTATION.
END
NNNN
  

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