Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
149 AM EST Tue Feb 8 2022
Valid 12Z Fri Feb 11 2022 - 12Z Tue Feb 15 2022
...Weather Pattern Overview...
A rather significant pattern change is likely in the works for
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 will probably
lead to some form of surface cyclogenesis by the end of the
forecast period across the southwestern U.S. 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.
...Guidance Evaluation/Predictability Assessment...
The deterministic model guidance has a good overall depiction of
the synoptic scale pattern across the U.S. through the weekend.
The 00Z CMC is a bit slower with the shortwave crossing Texas on
Sunday, whereas the GFS/UKMET/EC all suggest a more progressive
solution. At this time, this southern stream shortwave is not
expected to phase with the next Great Lakes disturbance before 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.
Things become more uncertain with the digging trough from the Gulf
of Alaska that will herald a pattern change to much of the western
U.S. next week. The ECMWF and its ensemble mean are faster with
the upper trough/closed low through Tuesday, compared to the
slower GFS and the well offshore 00Z CMC (the 12Z CMC was closer
to the 00Z ECMWF and is more favored than its newest 00Z run).
Teleconnections with the positive 500mb height anomaly (50N 140W)
on February 16th suggests the upper level trough axis would be
over the Desert Southwest and central Rockies, which is closer to
the 12Z CMC/00Z ECMWF compared to recent runs of the GFS that are
slower and farther northwest over Oregon.
The WPC fronts/pressures forecast was primarily derived from a
deterministic blend through Saturday, 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. for the end of the week
and into Saturday.
...Weather Highlights/Threats...
A strong but progressive clipper type low pressure system will
cross the northern Great Lakes on Friday and then northern New
England by Saturday, with the potential for several inches of snow
from northern Minnesota/Michigan to portions of upstate New York.
There will also be breezy to windy conditions across the Upper
Midwest and Great Lakes region 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. Depending on the eventual
evolution of the western trough and accompanying surface low,
precipitation may increase in coverage across portions of the
Rockies and Pacific Northwest by next Tuesday along with
increasing winds.
In terms of temperatures, the majority of the nation should be
near to slightly above average for highs to close out the week,
with the greatest warm departures on the order of 15-20 degrees
for portions of the Central Plains on Friday, and a brief warm-up
for the East Coast on Saturday. With the trough building in
across the east-central U.S. in time for the weekend, expect a
return to reality with highs running up to 15 degrees below
average from the Great Lakes to the Ohio Valley and Northeast by
Sunday. 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.
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