Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
155 AM EST Wed Feb 9 2022
Valid 12Z Sat Feb 12 2022 - 12Z Wed Feb 16 2022
...Weather Pattern Overview...
A rather significant pattern change is coming early next week as a
strong trough, originating over the Gulf of Alaska, drops
southeastward across the West Coast region. This will abruptly
replace the long-standing upper ridge (positive PNA pattern) that
will be over the western third of the nation through the end of
this week and into this weekend, which is expected to lead to
surface cyclogenesis by the middle of next across the western High
Plains. This will tend to displace the ridge axis farther east
across the Plains, although less amplified than before, and
resulting in more of a quasi-zonal flow pattern across much of the
central and eastern U.S. as the deep upper trough over the East
Coast region lifts out by early-mid next week. Additionally,
there will likely be an offshore low that develops off the East
Coast for late Sunday and then lifts northeastward to Nova Scotia
and Newfoundland.
...Guidance Evaluation/Predictability Assessment...
The 00Z deterministic model guidance has come into much better
agreement on the expected synoptic scale evolution of the western
U.S. trough that builds in for early next week. However, there
are still some model differences with shortwave energy crossing
the eastern U.S. through early Monday and its role in offshore
surface cyclogenesis. At this time, this southern stream
shortwave is not expected to phase with the next Great Lakes
disturbance until after the cold front exits the East Coast, and
this will limit the chances of an offshore low forming close
enough to the coast to cause issues, but future model trends will
continue to be monitored, especially if the stronger GFS solution
comes to pass.
The WPC fronts/pressures forecast was primarily derived from a
deterministic blend through the weekend, and then gradually
increasing percentages of the means through early next week. For
QPF, more of the ensemble biased corrected model, along with some
of the CMC/GFS/ECMWF, was used since the NBM appears too light
with its QPF across the north-central U.S. and lake effect snow
for the weekend.
...Weather Highlights/Threats...
A strong but progressive clipper type low pressure system will
cross southern Quebec and far northern New England by Saturday,
with the potential for light to moderate lake effect snow across
portions of Michigan and upstate New York in its wake. There will
also be breezy to windy conditions across the Great Lakes region
and the Northeast as this low moves through the region. Another
Canadian surface high drops southward across the central U.S. and
delivers dry conditions to much of the nation for the upcoming
weekend. It appears likely that a oceanic low will develop off
the East Coast by Sunday evening, but is currently expected to be
far enough offshore to keep most of the precipitation and wind
away from land, although some light snow is possible for the
Delmarva and coastal portions of New England. Depending on the
eventual evolution of the western trough and accompanying surface
low, precipitation is forecast to increase in coverage across
portions of the Rockies and Pacific Northwest by next Tuesday, and
an increase in showers and some storms across the central/southern
Plains by Wednesday and beyond along with gusty winds.
In terms of temperatures, there will a brief warm-up for the East
Coast on Saturday, followed by a return to below average readings
by Sunday and into early next week as the strong cold front ushers
in a renewed round of cold weather. Highs up to 20 degrees below
normal are possible for portions of the Great Lakes region this
weekend. It should be mild once again across most of the Plains
for Sunday and into Monday with the West Coast region beginning to
cool down with the trough building in, after anomalous warmth
across portions of California this weekend.
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