Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
244 AM EDT Fri May 11 2018

Valid May 11/0000 UTC thru May 14/1200 UTC

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

00Z model preferences with confidence intervals
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
NAM/GFS initialization errors do not seem to degrade their short
range forecasts.


Broad upper trough over the Gulf of Mexico/FL
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Preference: NAM/Canadian/UKMET blend; confidence slightly above
average

A broad upper trough moving east across the Gulf of Mexico closes
off a mid-level center off of western FL in 2-3 days.  The 00z GFS
appears to be suffering from gridscale feedback in a couple days
which then wraps/couples with the mid- to upper-level center,
producing a low offshore western FL with a closed isobar.  The 00z
ECMWF has joined the feedback club, with random precipitable water
maxima in the 2.8-3.5" range between May 12 2100 UTC and May 14
0400 UTC, with the last in the series making landfall west of
Charlotte Harbor early morning on May 14, dragging its surface
center along for the ride.  A compromise of the weaker 00z NAM,
00z UKMET, and 00z Canadian which show a surface/inverted trough,
is preferred with slightly above average confidence.


Broad mid-level cyclone parked across the West
Broad upper trough across eastern Canada & the Northeast
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The guidance is in good agreement with these systems/in these
areas.  A compromise of the 00z GFS, 00z NAM, 00z ECMWF, 00z
Canadian, and 00z UKMET is preferred with above average
confidence.  This should effectively deal with the 00z NAM's
strong bias with the western system effectively.


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

Roth