20000217: Eta changes-ADMIN NOTICE NOUS40 KWBC (fwd)

• To: nws-changes@xxxxxxxxxxxxxxxx
• Subject: 20000217: Eta changes-ADMIN NOTICE NOUS40 KWBC (fwd)
• From: Linda Miller <lmiller@xxxxxxxxxxxxxxxx>
• Date: Thu, 17 Feb 2000 09:52:12 -0700

663 
NOUS40 KWBC 171624
FOS/NOAAPORT NOTICE NO. 1602     FEBRUARY 17... 2000
PART 1 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

BRIEF DESCRIPTION OF CHANGE/S/

THIS IMPLEMENTATION WILL

1/ EXTEND 00Z AND 12Z RUNS OF THE MESO ETA OUT TO 60 HOURS
AND 06Z AND 18Z RUNS TO 48 HOURS...

2/ PROVIDE MORE AND HIGHER RESOLUTION OUTPUT VIA AWIPS
SBN...

3/ MAKE CHANGES TO THE CONVECTIVE SCHEME...

4/ RETURN TO USING THE WSR-88D VAD WINDS WITH A NEW QUALITY
CONTROL CODE FOR THEM AND 5/ ADD THE COMPUTATION OF THE
LOCATION OF RADIOSONDE DATA TAKING INTO ACCOUNT BALLOON
DRIFT.

REASON FOR CHANGE/S/

1/ NUMEROUS REQUESTS FROM THE FIELD AND NCEP CENTERS FOR
EXTENDED RANGE MESO ETA GUIDANCE.  THE 60 HOUR EXTENSION
PROVIDES COVERAGE OF THE SO-CALLED DAY 2 WITH THE 48 HOUR
PROVIDING AN OFF-TIME UPDATE.

2/ALL FOUR RUNS OF THE MESO ETA ARE UNIFORM IN THEIR RESOLUTION
/32 KM/ AND THIS CHANGE WILL UNIFY THE RESOLUTION OF GUIDANCE
PROVIDED FOR AWIPS OVER THE SBN.  A FULL COMPLEMENT OF GRIDS
212 /40 KM/ AND 215 /20 KM/ WILL BE PROVIDED WHICH IS IDENTICAL
TO THE FIELDS BEING TRANSMITTED TODAY FOR THE OFF-TIME RUNS.
ALL RUNS OF THE MESO ETA WILL BE IDENTIFIED IN WMO HEADERS
WITH THE MODEL GENERATION CODE OF 84. THE 00Z   12Z ONTIME
RUNS... KNOWN AS EARLY ETA... HAD BEEN IDENTIFIED AS 89 AND THE
06Z   18Z OFFTIME RUNS... KNOWN AS MESO ETA... HAD BEEN
IDENTIFIED AS 85.  ALSO... AN ALTERNATIVE SEA-LEVEL PRESSURE
FIELD WILL BE ADDED WHICH USES THE SHUELL TECHNIQUE AND THE
DYNAMIC TECHNIQUE /BONKERS ET AL. 1998/ WILL BE IMPLEMENTED
TO COMPUTE STORM MOTION WHICH IS USED IN THE CALCULATION OF
HELICITY.

3/ CHANGES ARE BEING MADE TO THE BETTS-MILLER-JANJIC CONVECTIVE
SCHEME TO ADDRESS TWO WELL KNOWN PRECIPITATION BIASES  HIGH
BIAS IN THE SOUTHEAST US ALONG THE COASTS OF THE GULF OF MEXICO
AND ATLANTIC OCEAN AND LOW BIAS /NON EXISTENCE/ OVER ELEVATED
TERRAIN OF THE WESTERN US.

4/ THE VAD WINDS REPRESENT A LARGE HOURLY DATA SET.  WITH THE
NEW QUALITY CONTROL CODE... WHICH INCLUDES A CHECK FOR THE
SIGNATURE FROM MIGRATORY BIRDS... THIS DATA CAN AGAIN BE
TURNED ON FOR USE BY THE 3D-VAR ANALYSIS.

5/ THE COMPUTATION OF THE DRIFT OF THE RADIOSONDE BALLOON
WITH TIME IS STRAIGHTFORWARD AND PRODUCES A UNIQUE
LATITUDE/LONGITUDE LOCATION AT EACH LEVEL OF THE ASCENT
WHICH WILL BE USED IN THE 3D-VAR. THIS IS AN IMPROVEMENT OVER
THE PREVIOUS TREATMENT OF RADIOSONDE DATA AS A VERTICAL
ASCENT DIRECTLY ABOVE THE RADIOSONDE RELEASE SITE.
END
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