Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
243 AM EDT Mon Aug 05 2019

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

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

00Z Model Evaluation with Preferences and Confidence
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...Overall Pattern Across the CONUS...
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Preference: General model blend
Confidence: Above average

---06Z UPDATE---
No significant change to the preliminary preference. The 00Z NAM
is more amplified with the trough in the East this week than other
models, and the remaining global models are now more closely
clustered around a less amplified scenario. Therefore, less weight
will be placed on the NAM by mid-week.

---PREVIOUS DISCUSSION---
The synoptic pattern continues to look relatively consistent, with
a persistent ridge in the Western U.S. and a trough over the East
that gets reinforced by some digging shortwaves embedded within
deeper layer northwest flow aloft. Deterministic models are in
fairly good agreement, and ECMWF ensemble spread is below the
previous 30-day average in many areas -- indicating generally
better than average model similarity for mid-summer.

Over the past couple model cycles, the NAM and UKMET have come
into better agreement with the other deterministic models and
ensemble means. These two models were excluded from the model
preference previously, but are now similar with the large scale
pattern. A broader model blend is preferred.

With respect to the forecast QPF, greatest weight was placed on
the GFS and ECMWF, which offered relatively consistent forecasts.
And slightly more weight was placed on the GFS as compared to the
ECMWF, as it showed more significant MCS activity on the periphery
of the ridge in the Plains, and showed more substantial QPF in the
West associated with a northward push of moisture and favorable
jet stream dynamics.


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

Lamers