Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
152 PM EST Thu Jan 24 2019

Valid Jan 24/1200 UTC thru Jan 28/0000 UTC

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

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

...Overall Pattern across the CONUS...

Preference: General model blend
Confidence: Slightly above average

---18Z UPDATE---
No change to the preliminary preference or reasoning.

---PREVIOUS DISCUSSION---
The highly amplified nature of the pattern is leading to fairly
good model agreement overall in the next few days. There are some
small differences, but these are not having a significant impact
on the precipitation forecast -- partially due to the fact of very
limited moisture availability over most of the CONUS.

Model spread is greatest with a shortwave that will be rounding
the base of the large Central-Eastern CONUS trough on Sunday. The
wave is currently over the central Pacific and approaching Alaska,
and model differences may continue for another several model
cycles. The 00Z ECMWF and UKMET had a stronger wave that digs a
bit further south and is slower along the Gulf Coast, which does
yield more widespread heavy rain as compared to the other models.
The ECMWF and UKMET are on the edge of ensemble distribution at
this point, with most other deterministic models and ensemble
members flatter, faster and further north with the wave in
comparison. The UKMET and ECMWF cannot be ruled out, but slightly
less emphasis on those models is recommended at this time in
Florida with respect to QPF.

Otherwise, a general model blend over the next few days seems (1)
fairly close to the deterministic model forecasts and (2)
reasonably representative of a solid consensus forecast. For these
reasons, a general model blend is the preference.


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

Lamers