Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
1228 PM EDT Fri Aug 30 2019

Valid Aug 30/1200 UTC thru Sep 03/0000 UTC

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

12Z Model Evaluation, Confidence, and Preferences
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...Overall Pattern Across the CONUS...
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Preference: 00Z GFS/CMC/ECMWF with some UKMET
Confidence: Above Average through 48 hours, Slightly Below Average
day 3

The synoptic pattern over the CONUS through the next 3 days is
expected to favor general troughing over the Great Lakes region
with some ridging through the inter-mountain West and northern
Rockies. Toward the end of Day 3, another shortwave trough
approaches the Pacific Northwest while ridging builds more over
the southwest U.S. A compact shortwave will drop through the
longwave troughing over the central/eastern U.S., helping to
reinforce the trough over the Northeast.

Overall, model agreement is above average during the forecast
period with relatively minor spread seen in the deterministic
guidance and within the ensemble spread. The NAM, as typical, is
too amplified with the Pacific Northwest shortwave by Day 3, and
the latest GFS is a bit faster with its progression across the
northern Plains.

The preference this cycle is for a general model blend, accounting
for the typical biases.


...Hurricane Dorian...
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Please refer to the official National Hurricane Center forecast
track

The latest forecast information for Hurricane Dorian is most
aligned with the 00Z ECMWF/CMC through 84 hours. Model spread
increases beyond that period, but the ECMWF/CMC falls in the
middle of the model envelope at this time.

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

Taylor