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 0714Z Apr 16, 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
314 AM EDT WED APR 16 2014

VALID APR 16/0000 UTC THRU APR 19/1200 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.
==============================================

...UPPER MIDWEST STORM LATER APPROACHING THE NORTHEAST IN A
WEAKENED STATE...

MIDWEST PREFERENCE: BLEND OF 00Z NAM/GFS/ECMWF
CONFIDENCE: SLIGHTLY ABOVE AVERAGE

NORTHEAST PREFERENCE: BLEND OF 00Z NAM/ECMWF/UKMET
CONFIDENCE: SLIGHTLY BELOW AVERAGE

THE NAM/GFS/ECMWF FORM A STRONG CLUSTER OF OPERATIONAL
MODELS...SUPPORTED BY THE ENSEMBLE MEANS...PARTICULARLY DURING THE
EARLY LIFE OF THIS SYSTEM WHEN IT WILL PRODUCE IMPACTFUL SNOWFALL
ACROSS THE UPPER MIDWEST. SEE THE HEAVY SNOW DISCUSSION...QPFHSD
FROM THE WPC WINTER WEATHER DESK FOR SNOWFALL DETAILS. 00Z RUNS
TRENDED DEEPER ALOFT ON DAY 1. THIS HELPED PULL THE NAM/GFS
SURFACE TROUGH BACK WEST AND INTO BETTER AGREEMENT WITH THE MORE
CONSISTENT ECMWF. IN PLAN VIEW 850-700 MB PLOTS THERE APPEARS TO
BE STRONG CONSENSUS REGARDING THERMAL PROFILES.

FOLLOWING THIS INITIAL LEAD SHORTWAVE EVENT...A LARGER SCALE
TROUGH WILL HAVE BECOME ESTABLISHED ALONG THE INTERNATIONAL
BORDER...AND WILL THEN SINK/SWING EAST TO SOUTHEASTWARD. AT THE
SURFACE THERE ARE RELATIVELY MINOR BUT NOTICEABLE DIFFERENCES
BETWEEN THE NAM/GFS/ECMWF. ALOFT...DIFFERENCES ARE MAGNIFIED. THE
GFS IS CERTAINLY ONE OF THE DEEPEST SOLUTIONS AT 500 MB. THE 00Z
ECMWF TRENDED MUCH MORE FLAT AND PROGRESSIVE...AND IS SUPPORTED BY
THE UKMET AT THE SURFACE AND ALOFT. THE NAM IS SLOW/DEEP AS THE
GFS...AND MAY STILL BE BLENDED REASONABLY WITH THE MORE
PROGRESSIVE SOLUTIONS.


...SOUTHERN STREAM WAVE AMPLIFYING ALONG THE GULF COAST...

PREFERENCE: BLEND OF 12Z ECMWF/UKMET
CONFIDENCE: SLIGHTLY BELOW AVERAGE

A SHORTWAVE DIPPING INTO THE SOUTHERN PLAINS ON DAY 1 WILL PHASE
WITH AN ACTIVE SUB-TROPICAL JET TO ALLOW THE FORMATION OF A BROAD
BUT ORGANIZED BAROCLINIC SYSTEM IN THE GULF OF MEXICO. THERE IS AN
INCREASING MODEL SIGNAL FOR HEAVY RAIN IN FLORIDA THURSDAY AND
FRIDAY. THE MODELS VARY IN THEIR DEGREE OF PHASING AND THE DEPTH
THAT THE GULF SYSTEM ATTAINS. GENERALLY THE ECMWF/UKMET/CANADIAN
FORECAST A SIMILAR SYSTEM CONCEPTUALLY...ALTHOUGH THE CANADIAN IS
ON THE WEAK SIDE. THE PAST FEW RUNS OF THE NAM HAVE HANDLED THIS
SYSTEM IN A REASONABLE FASHION...BUT ITS SOLUTION IS ONE OF THE
DEEPEST AMONG OPERATIONAL MODELS AND THE ENSEMBLES. THE
PERFORMANCE OF THE NAM REGARDING LARGE SCALE SYSTEMS AT THIS
LATITUDE IS NOT USUALLY THE BEST...SO WE WILL NOT YET INCLUDE IT
IN OUR PREFERENCE HERE...BUT WILL NOT RULE IT OUT
EITHER...ESPECIALLY WITH THE ECMWF TRENDING STRONGER. RECENT GFS
RUNS HAVE BEEN FAST AND UNDER-DEVELOPED.


...TROUGH CROSSING THE NORTHWEST AND REACHING THE NORTHERN PLAINS
THU/FRI...

PREFERENCE: BLEND OF 00Z ECMWF/UKMET/CANADIAN
CONFIDENCE: AVERAGE

THE MODELS PREDICT SIMILAR STRENGTH FOR THIS PROGRESSIVE SHORTER
WAVELENGTH SYSTEM. GIVEN TRENDS IN THE UKMET AND CANADIAN...THEY
NOW CLUSTER FAIRLY WELL WITH RESPECT TO THE LATITUDE AT WHICH THE
EMBEDDED VORTICITY MAXIMUM WILL FORM...ALTHOUGH THE NAM DOES NOT
FORM A CLOSED CIRCULATION. THE MAIN DIFFERENCE NOW IS
TIMING...WITH THE GFS/NAM BEING ON THE SLOW SIDE. THE SLOWER NCEP
SOLUTIONS ARE LIKELY RELATED IN PART TO THEIR DEEPER SOLUTION
DOWNSTREAM OVER THE GREAT LAKES WHICH PROPS UP SHORTWAVE RIDGING
FARTHER WEST ACROSS THE PLAINS ON THU/FRI.


...SYSTEM ENTERING THE SOUTHWEST U.S...

PREFERENCE: BLEND OF THE OPERATIONAL MODELS
CONFIDENCE: AVERAGE

THE MODELS WILL NOT APPEAR COMPLETELY IN PHASE WITH ONE ANOTHER AT
500 MB...GIVEN THE BROAD WAVELENGTH AND WEAK GRADIENTS.
DIFFERENCES AT THE SURFACE TO 700 MB ARE MUCH LESS PRONOUNCED. THE
UKMET AND CANADIAN TRENDED TOWARD OUR FAVORED SOLUTION BASED ON
THE ENSEMBLE SPREAD AND MORE CONSISTENT GFS/ECMWF. THERE IS NOW NO
STRONG PREFERENCE...ALTHOUGH SOME MEANINGFUL SMALL SCALE
DIFFERENCES MAY STILL ARISE IN FUTURE MODEL CYCLES.


...PACIFIC NORTHWEST LATE FRIDAY...

PREFERENCE: BLEND OF THE OPERATIONAL MODELS...EXCLUDING THE 00Z
ECMWF
CONFIDENCE: AVERAGE

THE IMPACTS FROM THIS SYSTEM WILL LIKELY HOLD OFF UNTIL DAY 4.
THROUGH DAY 3 THERE IS STRONG MODEL AGREEMENT ON THE LARGE SCALE.
WITH ITS 00Z RUN THE CANADIAN IMPROVED UPON ITS TRACK OF THE
SURFACE LOW/FRONT. THE ECMWF...ON THE OTHER HAND...TRENDED FASTER
ALOFT...WITH A MORE STRONGLY PRONOUNCED NEGATIVE TILT BY DAY 3.
THIS IS A SLIGHT DIFFERENCE...BUT FOR NOW WE WILL KEEP OUR
PREFERENCE TIED TO THE NAM AND GLOBAL MODEL CONSENSUS.

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

BURKE