THE WEATHER PREDICTION CENTER

COLLEGE PARK, MD


MODEL DIAGNOSTIC DISCUSSION


[Abbreviations and acronyms used in this product]
Geographic boundaries:    Map 1- [Color] [B/W Print Version]      Map 2 - [Color] [B/W Print Version]



MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
256 AM EDT SAT SEP 20 2014

VALID SEP 20/0000 UTC THRU SEP 23/1200 UTC

...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...

==============================================
00Z MODEL EVALUATION AND PREFERENCES
==============================================
NAM/GFS INITIALIZATION ERRORS DO NOT APPEAR TO
SIGNIFICANTLY AFFECT THEIR LARGE SCALE OUTPUT.
==============================================

...REMNANTS OF ODILE... 
 
PREFERENCE: BLEND OF 00Z NAM/GFS/ECMWF/UKMET
CONFIDENCE: AVERAGE

THE LOWER TO MIDDLE LEVEL REMNANTS OF PACIFIC TROPICAL CYCLONE
ODILE...DEFINED AS EITHER A SMALL CIRCULATION OR SHEAR AXIS...ARE
FORECAST TO STALL OVER EASTERN NM AND WEST TX...TRAPPED WITHIN A
BUILDING UPPER LEVEL RIDGE.


...CLOSED LOW INITIALLY OVER CALIFORNIA...
 
PREFERENCE: ANY OF THE 19/12Z OPERATIONAL MODELS...20/00Z
OPERATIONAL MODELS OR 19/12Z GEFS MEAN
CONFIDENCE: ABOVE AVERAGE
 
FEW MODEL DIFFERENCES EXIST INTO DAY 2...WITH THE 00Z NAM LAGGING
A BIT BEHIND THE GFS/EC/GEFS ON DAY 3 WHILE THE CANADIAN WAS
FASTEST.  EVEN SO...DIFFERENCES IN THE MODELS ARE FAIRLY MINOR
FROM DAY 2 THROUGH DAY 3.

...UPPER TROUGH DIGGING INTO THE EASTERN U.S THIS WEEKEND... 
...SURFACE LOW DEVELOPING OFF THE SOUTHEAST U.S. COAST SATURDAY...

PREFERENCE: BLEND OF 20/00Z ECMWF/GFS
CONFIDENCE: AVERAGE

THE UKMET JOINED THE CANADIAN IN BEING A STRONG OUTLIER IN TERMS
OF BRINGING A COASTAL LOW PRESSURE ALONG OR INLAND DURING PARTS OF
ITS JOURNEY FROM THE CAROLINAS TOWARD NEW ENGLAND. THE CONSENSUS
OVER MULTIPLE MODEL CYCLES IS FOR A POSITION FARTHER OFFSHORE AND
REMAINING OFFSHORE WHILE BEING ABSORBED BY SYNOPTIC LOW PRESSURE
OVER NEW ENGLAND. EVEN SO...THE PICTURE HERE BY LATE DAY 2 INTO
DAY 3 HAS BEEN CLOUDIED BY THE WAY THE MODELS ALLOW THE NORTHERN
AND SOUTHERN FEATURES TO INTERACT.  RATHER THAN HAVING ONE SYSTEM
PULL AWAY FROM THE NORTHEAST THERE HAS BEEN A GENERAL AGREEMENT IN
THE IDEA OF MULTIPLE SFC LOWS WHICH IMPACTS THE PROGRESSION OF A
SURFACE FRONT ACROSS THE EASTERN STATES.  DIMISSING THE HIGHLY
AMPLIFIED SOLNS OF THE UKMET AND CANADIAN...FEEL A GFS/ECMWF
OPERATIONAL BLEND WAS THE BEST COMPROMISE.  

...DEEP TROUGH LEANING INTO THE PACIFIC NORTHWEST...

PREFERENCE: ANY OF 20/00Z NAM/GFS/ECMWF/UKMET
CONFIDENCE: ABOVE AVERAGE

A DEEP LONGWAVE TROUGH OFFSHORE SHOULD HAVE LITTLE IMPACT THROUGH
SUNDAY NIGHT/MONDAY MORNING...BUT MODELS DO BRUSH THE PACIFIC NW
COAST WITH LOW PRESSURE ASSOCIATED WITH A LEAD SHORTWAVE THIS
WEEKEND. THE 20/00Z GFS GOT TO BE A BIT FASTER THAN THE OTHER
GLOBAL MODELS BY DAY 3 BUT EVEN THE GFS WAS NOT DRASTICALLY
OUTSIDE THE ENVELOPE OF SOLNS FROM THE OPERATIONAL MODELS OR THE
ENSEMBLES.

...MODEL TREND GRAPHICS AT
www.wpc.ncep.noaa.gov/html/model2.shtml...
...500 MB FORECASTS AT
www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml...

BANN





Last Updated: 256 AM EDT SAT SEP 20 2014