Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
147 AM EST Thu Jan 6 2022
Valid 12Z Sun Jan 9 2022 - 12Z Thu Jan 13 2022
...General Pattern Overview...
A deep upper level trough coupled with an arctic surface high will
be present across the north-central U.S. and then the East Coast
through Tuesday with an amplified upper level flow pattern in
place, and an upper ridge over the West Coast on Sunday. A split
flow pattern develops over the eastern Pacific and this leads to a
potential closed low near the Desert Southwest, and progressive
shortwave impulses tracking from western Canada to the Great Lakes
through the middle of the week.
...Guidance/Predictability Assessment...
The 00Z model guidance suite and ensembles continue to agree quite
well on the overall synoptic scale pattern, particularly through
Monday. Going in early next week, the models still have a good
handle on the deep trough over the East Coast region and the
timing of the cold front passage. Then models and ensemble
members continue to vary for specifics of how eastern Pacific
shortwave energy may split as it nears the West Coast. These
differences ultimately affect flow over/near the Southwest as well
as locations east of the Rockies, with northern stream flow
determined in part by how Pacific energy goes around the western
U.S. ridge and southern tier flow influenced by the pattern to the
west.
The WPC forecast was based primarily on a multi-deterministic
model blend through Tuesday, and then gradually increasing use of
the ECENS and GEFS means through early next week while still
keeping about 50 percent of a CMC/ECMWF/GFS blend..
...Hazards/Sensible Weather Highlights...
Gulf moisture advecting northward ahead of a developing
Plains/Midwest cold front will support increasing coverage of
showers and thunderstorms from eastern Texas and the central Gulf
Coast to the central Appalachians and Mid-Atlantic region this
weekend, with lighter precipitation expected farther north. There
will likely be some embedded heavier rainfall across portions of
the Deep South where convection is persistent, and some localized
flooding is within the realm of possibility. Areas from the upper
Great Lakes to the Northeast could see wintry weather, with the
best snowfall prospects over Michigan and northern New York as a
result of lake effect snow. Freezing rain and/or sleet may be
among the hazards over and near parts of the northern half of the
Appalachians for a time as moisture overruns cold air at the
surface. Dry conditions will likely prevail over a majority of
the country for Monday and Tuesday. Exceptions include some
showers and mountain snow over western Washington and Oregon as
one or more systems cross the region and some precipitation over
the Southwest and southern Plains by Wednesday.
The next blast of arctic air makes its presence known across the
Northern Plains and Upper Midwest by Sunday in the wake of the
strong cold front, and this cold weather will eventually reach the
East Coast in modified form as well, bringing highs down to 10-25F
below normal from the Mid-Atlantic through New England on Tuesday
for one of the coldest days of the year thus far. It should still
be rather mild across the Southeast U.S. ahead of the front on
Sunday before a return to reality by Monday. The northern-central
Plains will trend warmer next week, reaching 10-15F or so above
normal over some locations by Tuesday-Wednesday. Seasonably cold
conditions are likely west of the Continental Divide with readings
generally within 10 degrees of climatological averages.
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
WPC medium range 500mb heights, surface systems, weather grids,
quantitative precipitation, winter weather outlook probabilities
and heat indices are at:
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