Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
129 AM EST Sun Feb 23 2020
Valid 12Z Wed Feb 26 2020 - 12Z Sun Mar 01 2020
...Overview and Guidance/Predictability Assessment...
Western ridging will eventually be eroded by later in the week as
eastern troughing slowly moves its axis offshore by the end of
next weekend. The 18Z GFS/12Z ECMWF and their ensembles offered a
reasonable starting point to the forecast through the period. The
lead pair of systems will coalesce into a rather robust storm over
the Northeast/southern Canada late Wed into Thu before lifting
into eastern Quebec. A Pacific system is expected to drop into
WA/OR by next weekend and then perhaps push eastward in two pieces
next Sunday as high pressure moves through the Midwest/Southeast.
The models continued to struggle with the eastern Pacific
evolution next weekend in timing/orientation/amplitude so a trend
toward increased ensemble weighting was prudent.
...Weather/Hazard Highlights...
Some frontal-forced modest to perhaps locally heavy rain is
possible on Wed over Florida with more garden-variety rain up the
East Coast. Precipitation on the northwest side of the system will
support a swath of snow from the Great Lakes/Midwest to northern
New England. Temperatures will trend cooler with time behind the
system, generally for a couple days, before rebounding back toward
average. Lake-effect snow will linger for a day or two, especially
downwind of Lake Ontario. Some record lows (or low maxes) may be
approached Fri/Sat as the core of the cold slides into the East
Coast.
By contrast, the West will see generally dry conditions for most
of the week before the Pacific system comes ashore. Temperatures
about 10-20 deg above average (and even some record highs) can be
expected Wed-Sat. Light rain/snow will first push into coastal
WA/OR late Fri with an expansions southward into NorCal/Sierra and
eastward toward the Divide on Sat.
Fracasso
Additional 3-7 Day Hazards information can be found on the WPC
medium range hazards 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