Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
1253 PM EDT Tue Jun 18 2019

Valid Jun 18/1200 UTC thru Jun 22/0000 UTC

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

12Z Model Evaluation...with Confidence and Preferences
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

...Eastern and Central CONUS...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Preference: General model blend through Day 2; GFS/ECMWF blend Day
3
Confidence: Slightly Above Average

General cyclonic flow over the eastern 2/3 of the CONUS is
expected through tomorrow with an additional trough swinging
through the mid-Atlantic and Northeast Thursday into Friday.
Overall, the latest guidance has a reasonable handle on the large
scale mass fields with perhaps the GFS being a bit too fast while
the NAM is on the stronger side compared to the model consensus.
As the surface low tracks through PA and NY, there is some
latitudinal spread (UKMET/ECMWF northern side; NAM/GFS southern
side). Ultimately this affects the QPF distribution for Day 3.
Overall, with these relatively minor differences in mind, the
preferred blend at this time will be for a general model blend
through Day 2 followed by a GFS/ECMWF blend for Day 3.


...Western CONUS...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Preference: Non-UKMET
Confidence: Average

An anomalous closed low will drop into the Pacific Northwest
Wednesday and will carve out longwave troughing across the
interior West through the rest of the forecast period. The center
of the closed low is expected to settle over eastern MT or western
ND by Friday with its axis extending southwestward through
WY/UT/NV. Outside of minor perturbations that will work through
the base of the trough over the next several days, there is
relatively higher than normal confidence in the forecast mass
fields and above normal agreement seen in the latest model
guidance. As such, a general model blend is preferred at this
time.


Model trends at www.wpc.noaa.gov/html/model2.html
500 mb forecasts at www.wpc.noaa.gov/h5pref/h5pref.shtml

Taylor