Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
256 AM EDT Fri Apr 15 2022
Valid 12Z Mon Apr 18 2022 - 12Z Fri Apr 22 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 surface low
over the Great Lakes with a trailing cold front that will reach
the East Coast around Monday night, with a triple point low likely
developing near the Northeast U.S. on Tuesday. 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 next 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, and although
mesoscale differences become more apparent going forward, the
overall synoptic scale depiction remains good through the
remainder of the week. One of the more noticeable changes in the
guidance is with the 00Z ECMWF being much more progressive with
the building trough over the western U.S. by next Friday compared
to its prior 12Z run, and also ahead of the 00Z model consensus.
Therefore the 12Z ECMWF would be preferable for the
central/western part of the U.S. instead of the latest 00Z run.
The 00Z GFS/CMC/GEFS appear to handle that trough well, along with
the 12Z ECENS/ECMWF. The WPC forecast was primarily derived from
a multi-deterministic blend through Tuesday, and then gradually
incorporated more of the ECENS/GEFS means for the latter half of
next week.
...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 arriving Thursday and early Friday, extending farther south
into central California and also affecting areas to the north.
This will be 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 1-2 feet of snow for the Sierra.
Elsewhere across the continental U.S., showers and thunderstorms
will be exiting the East Coast region early in the week, followed
by dry weather as high pressure settles into the region. Another
round of organized showers and storms is likely across the central
U.S. by midweek as Gulf moisture is advected northward ahead of
the organizing storm system over the central Plains.
Temperatures are expected to remain rather chilly from the
northern Plains to the Great Lakes and Appalachians through much
of the upcoming week, and these below average readings should also
include much of the East Coast region through about Wednesday as
the cold Canadian surface high governs the weather pattern. On
the contrary, warm conditions are currently expected across much
of the interior western U.S. for the majority of the forecast
period, with above normal readings probable across the central and
southern Plains on Wednesday ahead of the cold front.
Temperatures should also moderate for the Eastern U.S. by Thursday
as the surface high moves off the coast and warmer southerly flow
commences.
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