Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
300 AM EDT Mon Mar 28 2022
Valid 12Z Thu Mar 31 2022 - 12Z Mon Apr 04 2022
...A deep and windy storm to bring a late week threat of Upper
Great Lakes heavy snow and heavy rain/severe weather to the East...
...Guidance Evaluation/Predictability Assessment...
The WPC medium range product suite was primarily derived from a
composite of best clustered guidance from the 18 UTC GFS and 12
UTC ECMWF/Canadian along with the 01 UTC National Blend of Models
days 3/4 (Thursday-Friday) in a stormy pattern with above normal
predictability. This blend is also well supported by ensembles and
00 UTC model guidance.
Embedded smaller scale system differences in the main two flow
streams and run to run continuity variance becomes more
problematic from the weekend onward despite reasonably similar
larger scale pattern evolutions. A blend of more compatible
guidance from the 18 UTC GEFS mean and 12 UTC ECMWF ensemble mean
tends to mitigate the less predictable forecast components while
inclusion of the most compatible model, the 12 UTC ECMWF, provides
a bit more detail consistent with a pattern with near average
predictability. Overall, WPC product continuity is well maintained
with this strategy and the forecast seems in line with a composite
of 00 UTC guidance.
...Overview and Weather Highlights/Threats...
A deep and windy storm set to lift from the Great Lakes to eastern
Canada Thursday into Friday offers a threat for wrapping heavy
snows north of the low track. Heavy rainfall will sweep across the
Eastern Seaboard with frontal system progression Thursday along
with a severe weather threat focus over the Mid-Atlantic as per
SPC.
A protracted series of more modest upstream upper trough energies
and frontal systems forecast to dig with some uncertainty through
the West later week into next week could each provide an
opportunity for enhanced rounds of wintry weather, mainly for the
north-central Intermountain West/Rockies. Potential system
amplitude and progression into next weekend/early next week would
favor return moisture into a wavy frontal pattern. This may
support a heavy rainfall focus from the Gulf Coast states to the
Southeast/Mid-Atlantic. By early next week there is also a
guidance signal to bring more energetic Pacific flow toward the
West Coast in two streams to be monitored.
Schichtel
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