Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
256 AM EDT Thu May 14 2020
Valid May 14/0000 UTC thru May 17/1200 UTC
...See NOUS42 KWNO (ADMSDM) for the status of the upper air
ingest...
00Z Model Evaluation Including Preferences and Confidence
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...Closed low over Alberta tracking to the Upper Great Lakes
Thu...then across Northern New England Fri...
...Surface low moving from the north central US tonight into
Northern New England Fri...
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Preference: 00Z NAM, 00Z ECMWF, GEFS/ECENS blend
Confidence: Average
07Z update: No significant changes noted with the rest of the
guidance. The 00Z ECMWF trended favorably from its prior run and
is favored.
---previous discussion---
Shortwave energy will move from southern Alberta and northern
Plains toward the Great Lakes over the next 24 hours. Through
about 15.12Z, the guidance shows above average agreement aloft and
at the surface, but beyond that time frame, timing differences
begin to creep up. The GFS becomes a slower outlier along with the
CMC. The NAM/ECMWF offer a middle ground approach with the UKMET a
bit ahead of the rest of the deterministic guidance. Looking at
the ensembles, the GEFS/ECENS means would also be a good approach
after 15.12Z.
....Closed mid level low off the Pacific Northwest coast
Thu...moving to the Northern Plains Sat...
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Preference: General model blend
Confidence: Above average
07Z update: No changes from previous preference.
---previous discussion----
Model guidance confidence and agreement remains above average with
the expected evolution of a closed upper level low off the Pacific
Northwest coast later today that then tracks through the Northern
Rockies through the end of the forecast period. A general model
blend suffices.
...Mid level trough over northern Mexico Thu...moving into central
TX Sat...
...Surface low over eastern NM/west TX Fri...crossing into central
TX Sat...
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Preference: non-00Z CMC blend
Confidence: Average
07z update: No changes from previous discussion, the 00Z CMC
remains the southern outlier but the spread has lessened somewhat
from the 12Z cycle.
---previous discussion---
Longwave troughing over northern Mexico today is forecast to track
eastward over New Mexico into central Texas by Saturday. Overall,
model clustering has improved with the mid level feature but there
remains some latitudinal spread in the feature, especially after
60 hours. The ECMWF, while an earlier northern solution, has
remained consistent with some northward adjustment/trend seen in
the 00Z GFS and 00Z NAM. This now solidly puts the CMC as a
southern outlier and a bit outside the ensemble range. For this
reason, the preferred blend removes the CMC and goes with a near
equal weight of the rest available guidance.
...Low pressure developing near the Bahamas Fri night into Sat ...
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Preference: 00Z GFS/12Z ECMWF/18Z GEFS mean/12Z ECMWF mean blend
Confidence: Average
07Z update: No major changes to the model guidance track of the
low pressure over the forecast period. The CMC remains a western
outlier while the UKMET is to the east. The ECMWF/GFS and their
respective ensemble means remains the favored blend.
---previous discussion---
The 00Z GFS did not stray too far from its earlier runs and
remains a consensus approach along with the 12Z ECMWF, as the area
of low pressure near the FL coast gradually organizes as it moves
north/northeast. The 18Z GEFS and 12Z ECENS means also remain
useful with similar tracks as the deterministic runs. The 12Z CMC
and 12Z UKMET remain outliers and discounted, where the CMC is
considerably too far to the left/west, while the UKMET is to the
right/east of the consensus. Forecast confidence remains at
average to slightly above average.
Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml
500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml
Taylor