Skip Navigation Links 
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
   Flood Outlook
   Winter Weather
   Storm Summaries
   Heat Index
   Tropical Products
   Daily Weather Map
   GIS Products
Current Watches/

Satellite and Radar Imagery
  GOES-East Satellite
  GOES-West Satellite
  National Radar
Product Archive
WPC Verification
   Medium Range
   Model Diagnostics
   Event Reviews
   Winter Weather
International Desks
Development and Training
WPC Overview
   About the WPC
   WPC History
   Other Sites
Meteorological Calculators
Contact Us
   About Our Site 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 1835Z Jul 14, 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
235 PM EDT Sat Jul 14 2018

Valid Jul 14/1200 UTC thru Jul 18/0000 UTC

...See NOUS42 KWNO (ADMNFD) for the status of the upper air

12Z Model Evaluation...with Preferences and Confidence

...Overall Model Analysis for the CONUS...

Overall Preference: 12Z ECMWF...Northwest U.S.
                    Blend of the 12Z GFS/ECMWF...remaining CONUS
General Confidence: Slightly above average

The pattern over the CONUS this weekend will be generally
dominated by high pressure aloft and weak flow, with one center
over the Four Corners region and another one extending from the
OH/TN Valleys south down across the Gulf Coast states. A broad
weakness between the two upper level high centers is expected to
remain over the central Plains and adjacent areas of the Midwest
through Sunday. However, the large scale pattern will change going
into early next week as a trough will be digging across the Upper
Midwest, Great Lakes and Northeast which will drive a cold front
across the Midwest and toward the Eastern Seaboard by Tuesday. The
guidance is in good agreement with this scenario, but the 12Z NAM
was seen as being a little sharper than the global models with the
height falls across the Great Lakes and OH Valley.

By Monday and Tuesday, there will be two troughs also impacting
the Northwest with one system crossing the Pacific Northwest and
the northern Rockies by Tuesday. The 12Z NAM is the strongest with
the first system, with the 12Z UKMET the weakest. The 12Z GFS is
overall the most progressive. The 12Z CMC/ECMWF solutions more
closely match the model consensus. Meanwhile, a second trough will
begin to impact the Pacific Northwest by Tuesday evening. The 12Z
NAM is the fastest solution with this second system, and the 12Z
CMC the slowest. There is very good model timing and depth
agreement in general with the 12Z GFS and 12Z ECMWF with this next

Based on the latest model clustering and trends, the ECMWF will be
the dominant preference across the Northwest U.S. through the
period, with a GFS/ECMWF blend elsewhere across the CONUS.

Model trends at
500 mb forecasts at