Prognostic Meteorological Discussion
Issued by NWS

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5
000
FXUS10 KWNH 201721
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
121 PM EDT SUN APR 20 2014

VALID APR 20/1200 UTC THRU APR 24/0000 UTC

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


12Z MODEL EVALUATION WITH MODEL PREFERENCES
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
NAM/GFS INITIALIZATION ERRORS DO NOT SEEM TO DEGRADE THEIR SHORT
RANGE FORECASTS.


PAIR OF CYCLONES APPROACHING THE PAC NW TUE & WED
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE:  NON-UKMET COMPROMISE
CONFIDENCE:  ABOVE AVERAGE

THE GUIDANCE IS IN EXCELLENT AGREEMENT WITH THE TUESDAY SYSTEM.
FOR LATE WEDNESDAY, THE 12Z UKMET IS WEAKER AND NORTH OF THE OTHER
GUIDANCE, LYING ON THE NORTHERN FRINGE OF THE 00Z GLOBAL ENSEMBLE
SPREAD.  A NON-UKMET COMPROMISE IS SUPPORTED BY THE BEST 00Z
GLOBAL ENSEMBLE CLUSTERING, AND IS PREFERRED WITH ABOVE AVERAGE
CONFIDENCE.


DEEP UPPER TROUGH MOVING THROUGH THE WEST TUE/WED
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE:  UKMET/GFS/ECMWF COMPROMISE
CONFIDENCE:  ABOVE AVERAGE

THE 12Z NAM IS MORE NORTHEASTERLY WITH THE MAIN CYCLONE/MAIN 500
HPA SHORTWAVE NEAR THE WESTERN US/CANADIAN BORDER THAN THE OTHER
DETERMINISTIC GUIDANCE -- ITS SOLUTION IS ON THE NORTHEAST FRINGE
OF THE 00Z GLOBAL ENSEMBLE GUIDANCE.  WITH NORTHERN STREAM RIDGING
STEADFAST ACROSS NORTHERN ALBERTA, BELIEVE THE CONSENSUS SHOWING A
MORE EASTERLY TRACK IS CORRECT HERE.  THE 12Z CANADIAN IS THE MOST
AMPLIFIED ALOFT, WHICH IS NOT SUPPORTED BY THE
FLATTENING/INCREASINGLY ZONAL FLOW UPSTREAM.  THE PREFERENCE IS
FOR A UKMET/GFS/ECMWF COMPROMISE WITH ABOVE AVERAGE CONFIDENCE
CONSIDERING THE SYNOPTIC PATTERN IN WHICH THE SYSTEM IS EMBEDDED.


SYSTEM MOVING ACROSS THE GREAT LAKES/NEW ENGLAND TUE & WED
DEEP UPPER TROUGH DEPARTING THE SOUTHEAST TODAY
WEAK MID-LEVEL SHORTWAVE PASSING JUST NORTH OF MAINE ON MON
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE:  GENERAL MODEL COMPROMISE
CONFIDENCE:  ABOVE AVERAGE

THE MODELS SHOW EXCELLENT AGREEMENT WITH THESE SYSTEMS.  A GENERAL
MODEL COMPROMISE IS PREFERRED TO IRON OUT ANY SMALLER SCALE DETAIL
DIFFERENCES WITH ABOVE AVERAGE CONFIDENCE.


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

ROTH
$$





USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.