Afternoon disco from LWX has important note about EURO AI
SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
An Arctic Front will reside in the vicinity of the Mid-Atlantic
Saturday night into Sunday as kind of the middle piece of this
leader-follower system. The leader system that impacted the area
Saturday will leave the trailing cold front behind, but also bring
the cold for the Sunday event. For the follower - the potential snow
event across the area Sunday - models historically have issues
with these set-ups. This case is no different with considerable
differences in model guidance just ~40 hours out from the onset
of precipitation.
Synoptically, an UL trough will move eastward into the Ohio
Valley Saturday night. A piece of energy will move ahead of this
feature being one of the parts of this storm. The region will
reside in the left exit region of a ~100 kt H5 jet. This is
favorable for upward motion, as indicated by several methods
including the long Q-vectors. Good agreement in FGEN bands
across the area as well. It should be noted the differences
between global models/ensembles. The CMCE/GEFS are notably more
bullish than the EPS. Regional models split differences among
themselves. Of note, the AI EURO has been consistent with
0.2-0.4" of QPF across the area for several days. This model
tends to overdo the broader field of QPF at further lead times,
but this signal is noteworthy based on latest verification
research.
Given the potential for 5" of snow (6" in the mountains), have
coordinated with neighboring offices and WPC in a Winter Storm Watch
for climo favored areas. Have concerns about mixing further
southeast towards the metros coupled with lower ratios. The current
snow forecast will likely change, so please monitor the latest
forecast for updates.
