Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
255 AM EDT Sat Apr 16 2022
Valid 12Z Tue Apr 19 2022 - 12Z Sat Apr 23 2022
...Weather Pattern Overview...
There will be three well-defined storm systems that will affect
the continental U.S. next week. The first will be a coastal low
near the Northeast U.S. coast on Tuesday that will intensify as it
lifts northward towards eastern Quebec, bringing rain, wind, and
mountain snow to New England. A large surface high will then
encompass the eastern half of the nation through Wednesday ahead
of the next developing storm system over the Plains, which should
result in another cold front reaching the East Coast by Friday.
The third system develops over the West Coast and Intermountain
West region for the end of the week as an amplified upper level
trough builds in from the Pacific, along with a downstream upper
ridge axis over the Plains.
...Model Guidance Evaluation...
The 00Z model guidance suite is initially in very good overall
agreement through the early-middle part of next week with above
average confidence, and although mesoscale differences become more
apparent going forward, the overall synoptic scale depiction
remains good through the remainder of the week and into Saturday.
By Thursday, the GFS becomes more progressive with the
shortwave/surface low crossing the northern tier states, but is
very close to its ensemble mean. For the end of the week, the CMC
holds the axis of the upper trough farther back to the west
compared to the ECMWF and the ensemble means, whereas the GFS is
faster to lift the trough out of the Intermountain by Saturday.
The WPC forecast was primarily derived from a multi-deterministic
blend through Wednesday, and then gradually incorporated more of
the ECENS/GEFS means for the latter half of the forecast period.
...Sensible Weather/Threats...
In the precipitation department, the West Coast region is expected
to remain rather unsettled with two well defined events. The
first round of rain and mountain snow is expected late Monday into
Tuesday from northern California to Washington state, and the
second and more impactful system arriving Thursday and early
Friday, extending farther south into central California and also
affecting areas to the north. This late season event will deliver
highly beneficial precipitation to drought-stricken areas of
California, with the potential for up to three inches of rain in
some areas next week, and 1-3 feet of snow for the Sierra.
Elsewhere across the continental U.S., the surface low near New
England is expected to result in widespread rain, wind, and
potentially moderate to heavy snow for the higher terrain of the
Adirondacks and extending to northern Maine through Tuesday
afternoon. Another round of organized showers and storms is
likely to develop across the central U.S. and extending northward
to the Great Lakes by midweek as Gulf moisture is advected
northward ahead of the organizing storm system over the central
Plains. Additional moderate to heavy snow is also expected for
portions of the northern Rockies for the end of the week.
Temperatures are expected to remain rather chilly from the
northern Plains to the Great Lakes and Appalachians through about
Wednesday, and these below average readings may persist even
longer across North Dakota and northern Minnesota going through
the end of the week. On the contrary, warm conditions are
currently expected across much of the interior western U.S. for
the majority of the forecast period ahead of the upper trough,
with well above normal readings probable across the western High
Plains by the end of the week and into Texas. Temperatures should
also moderate for the Eastern U.S. by Thursday as the surface high
moves off the coast and warmer southerly flow commences. Windy
conditions are also likely from western Texas to the western
Dakotas on Tuesday with strong southerly flow expected.
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, 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