Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
200 AM EST Sat Jan 15 2022
Valid 12Z Tue Jan 18 2022 - 12Z Sat Jan 22 2022
...Pattern Overview...
Guidance overall agrees that a mean upper ridge will amplify off
the West Coast mid-later next week. Downstream, this should force
an increasingly dominant series of northern stream impulses dig
down from Canada to carve out a large and central U.S. centered
mean upper trough.
...Guidance/Predictability Assessment...
The WPC forecast suite was mainly derived from a composite blend
of reasonably well clustered solutions from the 18 UTC GFS and 12
UTC ECMWF/UKMET/Canadian days 3-5 (Tue-Thu) along with the 01 UTC
NBM in a pattern with seemingly above normal predictability. WPC
product continuity is well maintained. Forecast spread and model
run to run consistency become a bit less manageable into days 6/7
(Fri-next Saturday). Prefer a composite of the larger scale
compatible 18 UTC GEFS mean and 12 UTC NAEFS/ECMWF ensemble means
to maintain max WPC product continuity beyond less predictable
smaller scale embedded system detail. Overall, the resultant
solution seems reasonable and a similar pattern
amplification/evolution is depicted with composite of newer 12 UTC
model and ensemble runs.
...Weather Highlights/Hazards...
A significant winter storm is slated to exit still windy New
England to the Canadian Maritimes by Tuesday as another organized
low pressure system digs into the north-central U.S. Low
development and subsequent track roughly eastward along the
U.S./Canadian border into Wed/Thu will bring some snow to the
Upper Midwest, Great Lakes then northern New England, with locally
higher totals expected near typical lake enhancement areas as cold
high pressure sweeps down across the central and eastern U.S. in
the wake of the low. Guidance varies with potential focus, but
suspect the wavy trailing cold front on the leading edge of this
Arctic blast will gain at least modest moisture from the Gulf of
Mexico to fuel an emerging area of precipitation over the
Southeast that offers some later next week potential for
overrunning snow/ice on the northern periphery of activity. The
Canadian and some ensemble members are more robust with
frontal/coastal wave amplitude and precipitation extent across the
region and over the East Coast at these longer time periods. The
main upper trough position is far enough West to not discount this
possibility.
Meanwhile, The West could see some light precipitation through the
period, particularly over the Pacific Northwest and into the
Northern Rockies as weakening systems cross the region, with
mainly dry conditions elsewhere.
Schichtel
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