Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
248 AM EDT Thu Aug 09 2018

Valid Aug 09/0000 UTC thru Aug 12/1200 UTC

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

00Z model evaluation and final preferences
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...Overall Synoptic Pattern across the CONUS...
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Preference: 00Z GFS/00Z ECMWF blend
Confidence: Average

The large scale pattern over the U.S. currently shows a longwave
trough over the eastern Pacific and a broader longwave trough over
the northeastern two thirds of the U.S. with a mid-level ridge
centered over the Great Basin between the two troughs. Over the
next 1-3 days, the ridge over the West will advance eastward into
the northern Plains as shortwave troughing advances across the
Pacific Northwest. Out East, the development of a closed low over
the Ohio Valley is expected by Sunday morning with a second closed
low over the southern High Plains.

Across the Northwest, compared to yesterday, the models have
slowed with their timing of a compact closed low, including the
00Z UKMET which now matches the consensus compared to the faster
12Z cycle.

Across the central and eastern U.S., the 00Z NAM is less favored
given it is a bit stronger with low pressure in the 850-700 mb
layer over West Texas compared to the remaining guidance and the
NAM is farthest north/east with a surface low in the northern
Mid-Atlantic region on Saturday and faster with the upper trough
progression across the Northeast. The ensemble means fit best
toward a blend of the 00Z GFS and 12Z ECMWF across the central and
eastern U.S. The 00Z UKMET/CMC have trended toward the 00Z
NAM/GFS/ECMWF regarding the strength of mid-level troughing over
New Mexico/Texas by Sunday morning but remain weaker than the
consensus.

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

Otto