Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
141 AM EST Wed Jan 5 2022
Valid 12Z Sat Jan 8 2022 - 12Z Wed Jan 12 2022
...General Pattern Overview...
An amplified but progressive upper level pattern is expected to be
in place through early next week with a deep trough tracking from
the Rockies to the East Coast, and a ridge axis moving into the
western U.S. from the eastern Pacific. By next Wednesday a second
trough moves across the Plains and a storm system begins
approaching the Pacific Northwest, with more of a quasi-zonal flow
pattern over the eastern U.S. as the earlier trough departs.
...Guidance/Predictability Assessment...
The 00Z model guidance suite and ensembles continue to agree quite
well on the overall synoptic scale pattern, particularly through
the upcoming weekend. 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. However, model
differences are more apparent for the western U.S. as a split flow
aloft likely develops. Timing differences exist among the
CMC/ECMWF/GFS with northern stream energy approaching the Pacific
Northwest, and latitudinal differences with a potential closed low
near southern California. By Wednesday, the GFS is faster with
this shortwave energy in the northern stream across the Great
Lakes and Ohio Valley, compared to the slower CMC/ECMWF guidance.
The WPC forecast was based primarily on a multi-deterministic
model blend through Sunday, 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 is expected to result in increasing
coverage of showers and thunderstorms from eastern Texas and the
central Gulf Coast, to the Ohio Valley and Mid-Atlantic region
this weekend, with lighter rainfall expected farther north. There
will likely be some embedded heavier rainfall across portions of
the Deep South where convection is persistent. Areas from the
upper Great Lakes to the Northeast could see wintry weather, with
the best snowfall prospects over northern New England and northern
New York. Parts of the Great Lakes may see lake effect snow
behind the passing front. Going into next week, dry conditions
are expected across most of the nation except for some showers and
mountain snow over western Washington and Oregon associated with
the next storm system.
Some moderation of the severe cold over the Plains/Midwest is
expected on Saturday ahead of the next arctic surge that reaches
into the northern tier states by Sunday and into Monday. The
second surge may not be quite as intense as what is expected for
the end of this week, but temperatures could still be 10-25F below
normal from eastern Montana to Wisconsin. From Saturday into
Sunday, above normal temperatures will progress from the southern
Plains to the Deep South and Southeast U.S., with overnight lows
on the order of 15-25 degrees above normal across the central Gulf
Coast region Sunday morning. Seasonably cold conditions are
likely west of the Continental Divide with readings generally
within 10 degrees of climatological averages, and 10-20 degrees
below normal for the East Coast by next Tuesday.
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