Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
305 AM EST Sat Jan 05 2019

Valid Jan 05/0000 UTC thru Jan 08/1200 UTC

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

00Z Model Evaluation...with Preferences and Confidence
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

...Overall Pattern Across the CONUS...
Preference: 00z ECMWF/GFS/NAM blend
Confidence: Average

08z update: No significant differences noted for the forecast
period with the rest of the 00z guidance now in. A general blend
of the 00z ECMWF/GFS/NAM will suffice for this cycle.

---previous discussion---
Overall model agreement through 84 hours is fairly good with not
much spread in the in the mass fields across the CONUS. The closed
low over the mid-Atlantic will lift off the coast on Saturday with
its associated surface low deepening as it races northeast near
Nova Scotia. Across the western US, a longwave trough will push
onshore late Saturday into Sunday. Through 60 hours, model
agreement is good and a general blend of available guidance would
suffice.

Beyond 60 hours (07.12z), as the troughing across the western US
pushes into the central Plains, bigger model differences begin to
develop especially in the mid/upper levels. The CMC holds a
stronger ridge across the southeast US the longest and is also
more progressive/deep with the trough across the central US. The
GFS/NAM are flatter, not as deep with the bulk of the energy
holding back across the northern Rockies. The 12z ECMWF remains in
good agreement with the 00z GFS and NAM. For this cycle, the WPC
preference is for a general model blend through 07.12z then a
blend consisting of the 12z ECMWF with the 00z GFS/NAM.

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

Taylor