Skip Navigation Links weather.gov 
NOAA logo - Click to go to the NOAA homepage National Weather Service   NWS logo - Click to go to the NWS homepage
The Weather Prediction Center

 
 

 

Follow the Weather Prediction Center on Facebook Follow the Weather Prediction Center on Twitter
NCEP Quarterly Newsletter
WPC Home
Analyses and Forecasts
   National High & Low
   WPC Discussions
   Surface Analysis
   Days ½-2½ CONUS
   Days 3-7 CONUS
   Days 4-8 Alaska
   QPF
   PQPF
   Flood Outlook
   Winter Weather
   Storm Summaries
   Heat Index
   Air Quality
   Tropical Products
   Daily Weather Map
   GIS Products
Current Watches/
Warnings

Satellite and Radar Imagery
   Satellite Images
   National Radar
Product Archive
WPC Verification
   QPF
   Medium Range
   Model Diagnostics
   Event Reviews
International Desks
Development and Training
   Development
WPC Overview
   About the WPC
   Staff
   WPC History
   Accomplishments
   Other Sites
   FAQs
Meteorological Calculators
Contact Us
   About Our Site
 
USA.gov is the U.S. Government's official web portal to all federal, state, and local government web resources and services.
 
Model Diagnostics Discussion
 
(Caution: Version displayed is not the latest version. - Issued 0441Z Oct 29, 2014)
 
Version Selection
Versions back from latest:  0   1   2   3   4   5   6   7   8   9   10   
 
Abbreviations and acronyms used in this product
 
Geographic Boundaries -  Map 1: Color  Black/White       Map 2: Color  Black/White


MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1241 AM EDT WED OCT 29 2014

VALID OCT 29/0000 UTC THRU NOV 01/1200 UTC

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


00Z NAM/GFS EVALUATION WITH PRELIMINARY MODEL PREFERENCES
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
NAM/GFS INITIALIZATION ERRORS DO NOT SEEM TO DEGRADE THEIR SHORT
RANGE FORECASTS.


AMPLIFIED TROUGH APPROACHING WESTERN NORTH AMERICA
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: CLOSE TO THE 00Z GFS
CONFIDENCE: ABOVE AVERAGE

THE 00Z NAM IS SLOW WITH THIS SYSTEM -- ITS USUAL BIAS -- WHILE
THE 12Z UKMET IS QUICK WITH THIS SYSTEM -- ITS USUAL BIAS.  THE
00Z GFS LIES IN THE MIDDLE OF THE GUIDANCE SPREAD AND IS CLOSE TO
THE 12Z ECMWF/18Z GEFS ENSEMBLE MEANS.


TROUGH AMPLIFYING ACROSS EASTERN NORTH AMERICA
CLOSED LOW POTENTIALLY DROPPING INTO THE CAROLINAS
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: SREF MEAN/ECMWF/GFS/GEFS MEAN COMPROMISE
CONFIDENCE: BELOW AVERAGE

TRENDS WITH THIS SYSTEM ARE MORE AMPLIFIED DUE TO THE AMPLIFYING
RIDGE ACROSS THE PLAINS AND AMPLIFYING TROUGH NEAR THE WEST COAST.
 THE 00Z NAM IS THE FARTHEST SOUTHWEST BY SATURDAY MORNING -- ITS
USUAL BIAS -- WHILE THE 12Z UKMET IS THE FARTHEST NORTHEAST, NEAR
THE 12Z ECMWF ENSEMBLE MEAN SOLUTION.  THE 18Z GEFS MEAN/00Z
GFS/12Z ECMWF/21Z SREF MEAN ARE IN RELATIVELY GOOD AGREEMENT WITH
THEIR FORECASTS.  THE MAIN PROBLEM IS HOW ANOMALOUS THIS PATTERN
BECOMES BY SATURDAY MORNING.  THE 12Z ECMWF SHOWS 500 HPA HEIGHT
ANOMALIES OF 5.5 SIGMAS BELOW AVERAGE, WHICH IS ROUGHLY A ONCE IN
A 50 YEAR EVENT.  THE ST. LOUIS UNIVERSITY CIPS ANALOGS INDICATE
THAT THE OCT 26 1990 (BONNER BRIDGE STORM), DEC 6 2003, DEC 6
1985, DEC 4 1987, NOV 6 2010, AND NOV 18 2008 PATTERNS ARE THE
CLOSEST MATCHES ALOFT TO WHAT IS FORECAST.  WITH A FORECAST THIS
EXTREME, CONFIDENCE IN ANY OF THE GUIDANCE/MODEL CHOICE IS BELOW
AVERAGE.


www.wpc.ncep.noaa.gov/html/model2.shtml...
www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml...

ROTH