Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
243 PM EDT Sat Apr 16 2022
Valid 12Z Tue Apr 19 2022 - 12Z Sat Apr 23 2022
...Weather Pattern Overview...
An active northern stream pattern over the CONUS likely culminates
in a large, closed low over the West Coast Thursday, perhaps into
Friday. Two lows/troughs track ahead of this low, one that lifts
north of New England on Wednesday and one that tracks from the
Northern Plains to New England by way of the northern Great Lakes
Tuesday night through Thursday night. Amplified ridging and above
normal temperatures occur between these three lows/troughs.
...Model Guidance Evaluation...
The overall synoptic depiction of the pattern is very strong in
deterministic guidance until Thursday when the 06Z GFS opens the
low off the Pacific Northwest, making it more progressive that
other guidance with a shortwave trough that reaches the northern
Plains by 12Z Saturday while the 00Z ECMWF/CMC keep a closed low
over the Desert SW through that time. The 12Z GFS is a bit slower,
but the trough still crosses the CO Rockies by 12Z Saturday.
Otherwise, the global deterministic guidance is in good agreement.
The WPC forecast was derived from a multi-deterministic blend
through Day 5/Wednesday night before favoring the ECMWF/CMC and
ensemble means from the GEFS/ECENS/CMCE.
...Sensible Weather/Threats...
Far northern CA into OR have precipitation in the forecast for
each of the four medium range days from back-to-back systems, the
second one stalling and potentially working south through much of
the rest of CA Friday into the weekend. This late season event
will deliver highly beneficial rainfall/mountain snow to
drought-stricken areas of California, with the potential for three
inches of liquid for most northern CA terrain with a few feet of
snow for the Sierra. Elsewhere across the continental U.S., the
deep low lifting from New England Tuesday night will allow
continued wrap around snow over Interior New England terrain into
Wednesday. The next wave to cross the northern Plains looks to
push most of its snow into the Canadian Prairies through midweek
while another round of organized showers and storms are likely to
develop across the central U.S. and extending northward to the
Great Lakes as Gulf moisture is advected northward ahead of the
organizing storm system. Heavy rain is possible, particularly over
the Ozarks to Mid-MS Valley Wednesday/Wednesday night.
Temperatures are expected to remain be below normal over the
northern Plains through next week, slowing the recovery/melt from
the recent blizzard as well as the expected snow tomorrow/Easter
Sunday. On the contrary, above normal temperatures are expected
across much of the interior western U.S. under ridging/south of
the midweek low passages over the northern Plains before shifting
east over the central/east-central portions of the CONUS into next
weekend.
Jackson
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, experimental excessive rainfall
outlook, 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/#page=ero
https://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4
https://www.wpc.ncep.noaa.gov/heat_index.shtml