Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
258 AM EDT Wed Mar 16 2022
Valid 12Z Sat Mar 19 2022 - 12Z Wed Mar 23 2022
***Strong low pressure system will likely produce heavy rain and
severe storms across portions of the southern U.S. by early next
week***
...Overview...
A rather active weather pattern will be developing across much of
the nation beginning this weekend, and particularly into the
beginning of next week as a deep upper level trough develops over
the Intermountain West as Pacific shortwave energy moves inland.
This will likely evolve into a closed upper low by Monday along
with an intensifying surface low over the central/southern Plains
that will eventually result in heavy rain and severe storms from
Texas to the Deep South by the end of the forecast period. There
will also be a well organized storm system across the Northeast
U.S. this weekend ahead of the central U.S. event.
...Guidance Evaluation/Predictability Assessment...
The 00Z model guidance suite is generally in above average
agreement through Monday night with the overall synoptic scale
pattern and the evolution of the main upper level trough/closed
low over the Rockies and Southern Plains. The GFS is stronger
with the closed low but still within the realm of possibility. By
Tuesday, the GFS and its ensemble mean are farther north across
Kansas, whereas the CMC/ECMWF solutions are favoring a position
over the Texas panhandle with the closed low. By the end of the
forecast period Wednesday, the 00Z ECMWF is out of phase across
the Pacific Northwest with a much stronger trough passage, whereas
the ensemble means are favored more of a ridge axis.
Taking these factors into account, the WPC forecast was primarily
based on a multi-deterministic model blend as a starting point
through about Monday, and then incorporated more of the ensemble
means whilst still maintaining smaller contributions from the
ECMWF/GFS/CMC.
...Weather Highlights/Threats...
The surface low tracking from the Ohio Valley to the Northeast on
Saturday will likely be accompanied by a swath of moderate to
locally heavy snow across northern portions of New England,
particularly central and northern Maine. Elsewhere, moderate rain
is expected from the northern Mid-Atlantic to central/southern New
England for the first half of the weekend.
Attention then turns to the Plains and Gulf Coast region as a
surface low becomes better organized by early Monday and taps into
a surge of Gulf moisture across Texas and the central Gulf Coast
region. The prospects for heavy rainfall and severe weather have
increased since yesterday, mainly later in the day Monday and
especially into Tuesday. Flooding rain could also be an issue as
multiple rounds of convection develop over the same general areas.
The Storm Prediction Center has additional information pertaining
to the severe weather potential.
In terms of temperatures, the East Coast should continue to have
above normal readings this weekend and into the middle of next
week as upper level ridging develops ahead of the deep trough over
the Plains. Even greater positive anomalies are likely across the
central and northern Plains by Sunday ahead of the storm system,
with highs up to 25 degrees above average, whereas a return to
slightly below average temperatures is expected across the Rockies
and the western High Plains under the upper level trough for
Monday and Tuesday. No major surges of arctic air are expected.
Hamrick
Additional 3-7 Day Hazard information can be found on the WPC
medium range hazards outlook chart at:
https://www.wpc.ncep.noaa.gov/threats/threats.php
https://www.wpc.ncep.noaa.gov/medr/5dayfcst500_wbg.gif
https://www.wpc.ncep.noaa.gov/medr/5dayfcst_wbg_conus.gif
https://www.wpc.ncep.noaa.gov/5km_grids/5km_gridsbody.html
https://www.wpc.ncep.noaa.gov/qpf/day4-7.shtml
https://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4
https://www.wpc.ncep.noaa.gov/heat_index.shtml