Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
1124 AM EST Sun Mar 03 2019
Valid Mar 03/1200 UTC thru Mar 07/0000 UTC
...See NOUS42 KWNO (ADMNFD) for the status of the upper air
ingest...
12Z Model Evaluation Including Preference and Confidence
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...Overall Pattern Across the CONUS...
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Preference: General model blend
Confidence: Slightly above average
There is very good model agreement on the overall synoptic pattern
with limited model spread. Relative to the past 30 days, ECMWF
ensemble spread of 500mb heights is considerably lower across the
western half of the country, and is only higher in the east due to
the concentration of numerous height contours with an amplified
trough (small positional differences lead to larger height
changes). However, the pattern across the East should be
relatively dry after the beginning of the Day 1 period, and thus
there is little practical impact on the QPF.
Most of the QPF should be concentrated in the West, especially by
Days 2-3. The 12Z GFS and NAM are slightly faster than the 00Z
ECMWF and UKMET with the trough. However, the differences were
relatively minor and a compromise approach was used. The NCEP
models also tend to split the QPF maxima in California, with a
minimum in the Central Sierra Nevada. This seems less likely than
a more continuous max along the length of the Sierra given broad
southwest flow, so if anything there was a slight preference given
to the ECMWF and UKMET.
Otherwise, the overall model preference is for a general model
blend with no systemic issues in any particular model forecast
that would argue for its exclusion.
Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml
500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml
Lamers