Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
331 PM EDT Fri Jul 12 2019

Valid Jul 12/1200 UTC thru Jul 16/0000 UTC

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

12Z Final Model Evaluation Including Preference and Forecast
Confidence
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...Overall Pattern Across the CONUS...
...Tropical Storm Barry...
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Preference: 12Z GFS/12Z ECMWF
Confidence: Slightly above average

19Z Update: The guidance is slowly converging on the track of
Tropical Storm Barry, towards the very consistent ECMWF track
which remained almost on top of itself through 48 hours with its
12Z run. The UKMET which had been well west of the consensus and
NHC track, has finally started to edge eastward, while the CMC
remains on the eastern edge of the envelope. A blend closest to
the NHC track remains as the ECMWF/GFS, with most weight on the
ECMWF due to its consistency and close match to NHC. By the end of
the period /Monday/ guidance diverges considerably with how T.S.
Barry will evolve with weak steering flow embedded within the
ridge. For now will stay close to the previous blend of which the
NHC track splits the difference.

Previous Discussion:
The dominant feature across much of the country will be Tropical
Storm Barry moving onshore the Gulf Coast Saturday before
meandering towards the lower Tennessee Valley early next week. The
ECMWF remains very close to the official NHC track, and while
there exists some spread beyond the first 48 hours, the 12Z GFS
has backed westward just a bit to become even more aligned with
the ECMWF/NHC for T.S. Barry. The new NAM backed west a bit too,
and is now inching closer to the TX coast at landfall. While this
is in line with the UKMET, due to a stronger ridge amplifying from
the SW, it is not preferred and does not match NHC. The 12Z
NAM-nest however is very close to the official track, but gets a
bit fast and NW late in its run.

Otherwise, the CONUS is relatively quiet minus a few impulses
rotating around the periphery/top of the ridge bringing the
potential for QPF and MCSs to the northern tier. Minor temporal
and spatial differences exist, but for now will focus the blend on
T.S. Barry and its motion into the large ridge across the CONUS
due it to being the most significant sensible weather impacts
during this time.


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

Weiss