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
   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
   Winter Weather
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 1900Z Jan 19, 2018)
 
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
200 PM EST FRI JAN 19 2018

VALID JAN 19/1200 UTC THRU JAN 23/0000 UTC

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

12Z MODEL EVALUATION INCLUDING PREFERENCES AND FORECAST CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
...SOUTHERN STREAM WAVE EJECTING NORTHEAST FROM THE GULF OF
MEXICO...

PREFERENCE: NON-CMC CONSENSUS
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
 
THE MODELS TAKE THE SOUTHERN STREAM CLOSED LOW/TROUGH OVER THE
WESTERN GULF COAST REGION GRADUALLY OFF TO THE EAST THROUGH THE
WEEKEND WHICH WILL ALLOW IT TO TRAVERSE THE REMAINDER OF THE GULF
COAST STATES. THE SYSTEM WILL WEAKEN AND BEGIN TO DAMPEN OUT BY
SUNDAY NIGHT AND MONDAY AS IT REACHES THE SOUTHEAST COAST AND
PUSHES OFFSHORE. THE 12Z GUIDANCE HAS COME INTO BETTER AGREEMENT
WITH THE ARRIVAL OF THE LATEST UKMET/CMC AND ECMWF SOLUTIONS. ALL
OF THE NON-NCEP MODELS TRENDED A LITTLE SLOWER AND IN LINE WITH
THE RELATIVELY SLOWER NAM AND GFS. HOWEVER...THE CMC SOLUTION DOES
STILL APPEAR TO BE PERHAPS A TAD TOO WEAK AND PROGRESSIVE AS THE
SYSTEM REACHES THE SOUTHEAST COAST AND THEN MOVES OFFSHORE AS
COMPARED TO THE OTHER MODELS. THEREFORE WILL PREFER A NON-CMC
CONSENSUS AT THIS TIME.
 
 
...DEEPENING TROUGH MOVING INLAND ACROSS THE SOUTHWEST...
...ENERGY EJECTING NORTHEAST ACROSS THE PLAINS/MIDWEST...
...ATTENDANT SURFACE LOW LIFTING TOWARD THE GREAT LAKES...

PREFERENCE: GENERAL MODEL BLEND...THROUGH 48 HOURS
            BLEND OF THE 12Z GFS/12Z UKMET...AFTER 48 HOURS
CONFIDENCE: AVERAGE

THE GUIDANCE AGREES IN TAKING A SOUTHERN STREAM TROUGH ACROSS CA
AND THROUGH THE SOUTHERN GREAT BASIN AND ADJACENT AREAS OF THE
SOUTHWEST U.S. THROUGH SATURDAY. THE SYSTEM IS THEN EXPECTED TO
AMPLIFY AND CLOSE OFF IN THE MID LEVELS OVER THE FOUR CORNERS
REGION SATURDAY NIGHT BEFORE EJECTING OUT ACROSS THE
CENTRAL/SOUTHERN HIGH PLAINS ON SUNDAY. THE STRONG HEIGHT FALLS
WILL DRIVE A WELL-ORGANIZED AREA OF LOW PRESSURE IN THE LEE OF THE
ROCKIES INVOLVING SOUTHEAST CO WHICH SHOULD THEN ADVANCE EAST
ACROSS SOUTHERN KS AND THEN LIFT NORTHEAST TOWARD THE GREAT LAKES
REGION SUNDAY NIGHT THROUGH MONDAY. THE MODEL MASS FIELD SPREAD IS
RATHER MINIMAL AS THE ENERGY TRAVERSES THE SOUTHWEST AND BROADER
FOUR CORNERS REGION...BUT AS THE SYSTEM REACHES THE
CENTRAL/SOUTHERN PLAINS...THE 12Z NAM BECOMES STRONGER THAN ANY
OTHER MODELS WITH ITS 500/700 MB REFLECTION AND TENDS TO LEAN A
BIT TOWARD THE FASTER SIDE OF THE GUIDANCE. THE 00Z ECMWF ALONG
WITH THE LATEST 12Z ECMWF SOLUTION ARE GENERALLY SLOWEST WITH THE
UPPER TROUGH/CLOSED LOW AND ALSO ARE A BIT SOUTH OF THE MODEL
CONSENSUS WITH THE CLOSED LOW TRACK INVOLVING THE MIDWEST. THE 12Z
GFS IS A BIT FASTER AND ONLY A LITTLE SLOWER THAN THE NAM. THE 12Z
UKMET AND 12Z CMC ARE IN BETWEEN THE SLOWER ECMWF AND FASTER
GFS...HOWEVER THE UKMET IS A LITTLE FARTHER SOUTH AND CLOSER TO
THE ECMWF...WITH THE CMC FARTHER NORTH AND CLOSER TO THE GFS. THE
00Z ECENS MEAN SUGGESTS THE ECMWF IS TOO SLOW BY THE END OF THE
PERIOD...AND THE 12Z GEFS MEAN IS A LITTLE FASTER THAN THE
OPERATIONAL GFS AND SUGGESTS THE RELATIVELY FASTER NAM IS WITHIN
THE REALM OF POSSIBILITIES. BASED ON ALL OF THIS...WILL SUGGEST A
GENERAL MODEL BLEND THROUGH 48 HOURS...FOLLOWED BY A SOLUTION THAT
APPROXIMATES THE MODEL CONSENSUS...WHICH AFTER 48 HOURS WOULD TEND
TO BE A BLEND OF THE GFS AND UKMET.


...NORTHERN STREAM TROUGH CLIPPING THE NORTHERN PLAINS...

PREFERENCE: BLEND OF THE 12Z GFS/12Z ECMWF
CONFIDENCE: SLIGHTLY ABOVE AVERAGE

A WEAKER NORTHERN STREAM TROUGH COMING IN OFF THE PACIFIC OCEAN
TODAY WILL CROSS THE PACIFIC NORTHWEST AND TRAVERSE THE NORTHERN
PLAINS THROUGH SUNDAY. THE 12Z GFS AND 12Z ECMWF ARE REASONABLY
WELL CLUSTERED AND HAVE DECENT SUPPORT FROM THE 12Z UKMET. THE 12Z
NAM AND 12Z CMC ARE JUST A LITTLE SLOWER THAN THE GFS/UKMET/ECMWF
CAMP. WILL CONTINUE TO FAVOR A BLEND OF THE GFS AND ECMWF AT THIS
TIME BASED ON CLUSTERING AND ENSEMBLE SUPPORT.


...UPPER TROUGH CROSSING INTO THE PACIFIC NORTHWEST BY SUNDAY...

PREFERENCE: BLEND OF THE 12Z GFS/12Z ECMWF
CONFIDENCE: SLIGHTLY ABOVE AVERAGE

THE NEXT UPPER TROUGH COMING ACROSS THE NORTHEAST PACIFIC WILL
ARRIVE OVER THE NORTHWEST U.S. ON SUNDAY AND THEN BEGIN TO FLATTEN
OUT BY MONDAY OVER THE GREAT BASIN AND NORTHERN ROCKIES. THE 12Z
NAM TENDS TO BE THE STRONGEST OVERALL SOLUTION WITH THE TROUGH AND
IS SOMEWHAT OF AN OUTLIER. MEANWHILE...THE 12Z UKMET HAS TRENDED
FASTER AND IS CLOSE TO THE WELL-CLUSTERED 12Z GFS AND 12Z ECMWF.
THIS COUPLED WITH FAVORABLE ENSEMBLE SUPPORT AGAIN SUGGESTS
LEANING TOWARD OF A BLEND OF THE GFS/ECMWF SOLUTIONS.

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