Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
238 PM EDT Sat Mar 16 2019
Valid Mar 16/1200 UTC thru Mar 20/0000 UTC
...See NOUS42 KWNO (ADMNFD) for the status of the upper air
ingest...
12Z Model Evaluation Including Preferences and Confidence
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...Overall Pattern Across the CONUS...
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Preference: 12z ECMWF/CMC/GFS blend
Confidence: Slightly Above Average
19z update: Overall fairly good run to run agreement with the rest
of the 12z guidance now available. Very minor speed differences
remain for the Mid-Atlantic shortwave (slightly faster GFS) but
looking at the QPF fields, most of the models are similar. The
UKMET/CMC are slightly wetter but overall amounts are light.
Toward the end of the forecast period, a subtle/weak shortwave
trough will pass over central/south Florida. Working on the
lingering/stalled front in place and daytime heating/instability,
convection is expected. The GFS is bullish with QPF while the rest
of the models are more conservative and is also faster compared to
the rest of the guidance.
Will keep the model blend preference for ECMWF/CMC/GFS but with
less weight toward the GFS over Florida.
---previous discussion---
The synoptic pattern into early next week across the CONUS is
expected to remain fairly persistent with a highly amplified ridge
over the Intermountain West with downstream troughing over the
Upper Midwest and eastern US. With sprawling high pressure over
much of the central/eastern US, precipitation will be fairly
limited and confined to the Gulf Coast region and south Florida
with some lake effect snows over the Northeast US. Overall, light
QPF amounts are expected.
Through 60 hours (19.00z), model variations are minimal such that
a general model blend would suffice for mass fields across the
CONUS. This includes a quick moving shortwave trough embedded in
the cyclonic flow that moves across the Ohio Valley and
Mid-Atlantic region. The latest model guidance is in relatively
good agreement spatially and temporally, and with the rest of the
CONUS very quiet, the general model blend looks good.
A shortwave trough is then expected to dig down into the
northern/central Plains. Here, the ECMWF is a bit more amplified
and faster compared to the GFS/NAM solutions. The 00z CMC is also
similar to the ECMWF, but even faster. Will lean on previous
preferences and side with the faster/amplified solution, favoring
the ECMWF/CMC solution.
Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml
500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml
Taylor