Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
320 PM EDT Wed Mar 23 2022
Valid 12Z Sat Mar 26 2022 - 12Z Wed Mar 30 2022
...Overview...
Deep troughing over the eastern U.S. this weekend will favor
seasonably cool temperatures from the Great Lakes to the
Northeast. A few embedded shortwaves will reinforce the cool
regime and bring blustery conditions and mostly light
precipitation. Meanwhile, a ridge anchored over the West will
break down as a large scale trough approaches and brings unsettled
and active weather to the Northwest and eventually much of the
West. As that aforementioned ridge moves into the Plains,
temperatures soar to much above normal values which could bring
record highs to the Intermountain West to the High Plains.
...Guidance Evaluation/Predictability Assessment...
The synoptic setup at the start of the period /Saturday/ shows
good model agreement and predictability with a western U.S. ridge
and eastern trough. A few embedded shortwaves will move through
the cyclonic flow this weekend over the Great Lakes with one
particular Clipper helping to induce cyclogenesis off the New
England coast Sunday into Monday. Here, model differences are
fairly minimal now and a near equal blend of the latest available
deterministic guidance was used.
The larger model differences are to the west tied to the
progression and amplitude of an eastern Pacific trough,
particularly the southern piece of that energy. As the positively
tilted trough axis reaches the western U.S., some guidance favors
closing off a upper low well offshore southern California (i.e.
00Z ECMWF) while others are closer to the coast/inland or more
progressive (GFS/CMC). The trend has been for a slower solution
that may close off, but perhaps not to the degree the 00Z ECMWF
(and its previous runs) suggest. It largely depends on how much
phasing or lack of with the northern stream - the ECMWF favors
more separation and allows the northern stream energy to race out
faster compared to the more phased GFS solution, especially by day
6/7. Either way, the models do show that the troughing reaches the
Rockies into the Plains by the end of the period where a strong
surface low may materialize. It's a lower confidence forecast,
especially from day 5 onward as the energy reaches the
Intermountain West. For now, the WPC blend for day 5-7 favored a
compromise of the ECMWF/GFS while including higher weights of the
ECENS/GEFS means to maintain continuity some while addressing the
uncertainty.
...Weather Highlights/Threats...
The shortwave energy progression and strong cyclonic flow over the
Great Lakes will produce mainly light precipitation across the
Great Lakes into portions of the central to northern Appalachians
and Northeast this weekend. The exception looks to be for the
favored high terrain and upslope flow areas of West Virginia where
late season snowfall accumulations could total several inches per
the latest Winter Weather Outlook probabilities. As the next
system moves into the western U.S. this weekend into early next
week, unsettled and active weather is expected on Day 4 /Sunday/
for the Northwest then Day 5-6 /Monday-Tuesday/ for much of
California, bringing beneficial and welcome rains to the valleys
with the higher elevation areas of the Sierra likely to see
several inches or more of snow. As that system moves into the
Plains and Midwest, enough cold air on the northern fringe of the
precipitation shield could allow for a wintry mix but details are
lacking that far out in time.
Unseasonably warm temperatures will build and expand underneath
upper ridging from the western U.S. into the Plains. Highs that
are 10-25F above normal will be common over the weekend from the
West Coast across the Great Basin and Southwest to the Plains, and
several daily record high temperatures could be set or tied. As
the ridge axis shifts eastward, warm anomalies of 15-25F are
likely for the High Plains Monday while the West Coast moderates
closer to normal. Warmer than normal temperatures remain forecast
in the south-central U.S. on Tuesday but may moderate Wednesday
while pushing into the Southeast. Meanwhile the East should see
near to below average temperatures given mean upper troughing,
with coolest temperatures of 10-20F below normal in the Great
Lakes and central Appalachians for the weekend and spreading into
the Northeast early next week.
Tate/Taylor
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
Hazards:
- Heavy precipitation across portions of the Central Great Basin,
California, and the Southwest, Sun-Mon, Mar 27-Mar 28.
- Heavy rain across portions of the Lower Mississippi Valley, the
Tennessee Valley, the Middle Mississippi Valley, the Mid-Atlantic,
the Southern Appalachians, the Southeast, the Southern Plains, and
the Ohio Valley, Wed, Mar 30.
- Heavy snow across portions of the Central Appalachians, Sat, Mar
26.
- Flooding possible across portions of the Lower Mississippi
Valley, the Northern Plains, the Tennessee Valley, the Great
Lakes, the Upper Mississippi Valley, the Southeast, the Southern
Plains, and the Ohio Valley.
- Flooding occurring or imminent across portions of the Upper
Mississippi Valley and the Northern Plains.
- Flooding likely across portions of the Upper Mississippi Valley
and the Northern Plains.
- High winds across portions of the Southeast, the Mid-Atlantic,
and the Southern Appalachians, Sat, Mar 26.
- Much above normal temperatures across portions of the Central
Rockies, the Central Great Basin, the Northern Rockies, the
Southern Rockies, California, the Northern Great Basin, and the
Southwest, Sat-Sun, Mar 26-Mar 27.
- Much above normal temperatures across portions of the Central
Plains, the Central Rockies, the Central Great Basin, the Northern
Plains, the Northern Rockies, the Southern Rockies, the Southern
Plains, and the Southwest, Sun-Mon, Mar 27-Mar 28.
- Much below normal temperatures across portions of the Northeast,
the Central Appalachians, the Mid-Atlantic, the Upper Mississippi
Valley, the Great Lakes, and the Ohio Valley, Sat-Mon, Mar 26-Mar
28.
- Much below normal temperatures across portions of the Great
Lakes, the Mid-Atlantic, the Northeast, and the Central
Appalachians, Sun-Mon, Mar 27-Mar 28.
- Heavy precipitation across portions of the Alaska Panhandle,
Mon-Wed, Mar 28-Mar 30.
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