Day 2
Valid 12Z Sun Sep 11 2022 - 12Z Mon Sep 12 2022
...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL IN PORTIONS OF THE
MID-ATLANTIC AND EASTERN WISCONSIN...
...Mid-Atlantic & Ohio Valley...
The disturbance that has been dawdling in the Lower Mississippi
Valley for several days will finally be picked up by the
amplifying trough heading for the Great Lakes and sent into the
Mid-Atlantic Sunday afternoon. The region will also become
positioned closer to the diffluent right-entrance region of a
250mb jet streak orienting itself along the spine of the
Appalachians. There will be no shortage of atmospheric moisture
from the Southeast to the Mid-Atlantic with a steady dose of 850mb
moisture flux and PWs ranging between 2.0-2.25". PWs in the
Mid-Atlantic are right around, if not slightly above, the 90th
climatological percentile for the date. The best instability will
be found from northern Florida to the Virginia Tidewater where
~1,000-2,000 J/kg of CAPE is expected Sunday afternoon. Storm
motions will be rather progressive, but deep warm cloud layers of
~12,000' AGL will allow for storms to be efficient rainfall
producers. It has also been a relatively wet 7-day period from
Pennsylvania on south through the central and southern
Appalachians with AHPS 7-day rainfall totals ranging between
300-600% of normal. With antecedent soil moisture conditions more
saturated than normal and heavy thunderstorms expected to contain
torrential downpours at times, a Slight Risk has been maintained
from northern North Carolina to the Lower Delaware and Susquehanna
Valleys. Poor drainage areas with sensitive soils and residing
within urbanized communities are most at-risk to flash flooding.