Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
259 AM EDT Sat Mar 27 2021
Valid 12Z Tue Mar 30 2021 - 12Z Sat Apr 03 2021
...Overall Weather Pattern...
The overall mid-upper level pattern across the continental U.S. is
expected to be rather amplified next week. An upper ridge will
briefly build across the eastern U.S. with an embedded southern
stream disturbance tracking across the southeastern U.S. through
Wednesday. Meanwhile, the next major storm system will be in
place over the Rockies and Intermountain West to begin the week,
and this storm system will steadily cross the central and eastern
U.S., reaching the East Coast around Thursday morning. A large
surface high should settle in across the Midwest and the
east-central U.S. for the end of the week.
...Model Guidance and Predictability...
The deterministic model guidance indicates above average agreement
on the main synoptic scale features through about Thursday
evening. The 00Z CMC becomes less amplified with the next storm
system approaching the Pacific Northwest for the end of the week,
and it's farther west with the downstream upper ridge axis across
the north-central Plains, so more focus was applied to the
GFS/ECMWF/UKMET solutions through Friday, and some more of the
ensemble means for next Saturday.
...Sensible weather and potential hazards...
The next system crosses the Plains with a strong surface low
trekking across southern Canada for the beginning to middle of the
week. This should advect enough Gulf moisture northward to
produce showers and storms from the central Gulf Coast to the
Northeast, and locally heavy rainfall is possible across the
Appalachians by midweek, although models differ on the axis of
heaviest rainfall. Strong winds are also expected across the
northern Plains and Upper Midwest on Tuesday owing to the strong
pressure gradient that will be in place.
Temperatures are expected to be above average ahead of the cold
front advancing across the Midwest, with readings of 5-15 degrees
above average across the Great Lakes and Ohio Valley on Tuesday.
An abrupt return to reality ensues by the middle of the week for
the northern Plains and Upper Midwest as a much colder airmass
advects into the region behind the front, with readings about
5-15+ degrees below average. This will also hold true for the
East Coast by Thursday and Friday. Spring-like warm returns to
much of the Plains for next weekend.
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, 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