Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
1215 PM EST Mon Feb 28 2022
Valid 12Z Thu Mar 03 2022 - 12Z Mon Mar 07 2022
...Heavy Rainfall Signal Emerging for the Mid-South and Ohio
Valley Sunday/Next Monday...
...Overview...
It remains the case that latest guidance continues to suggest that
a steadily building eastern Pacific upper ridge from late this
week into early next week will help to establish mean troughing
from central Canada through the western U.S. This general pattern
appears likely to persist beyond the medium range period. Ahead
of the developing mean trough, eastward progression of an initial
Rockies/High Plains upper ridge will eventually displace an
eastern North American mean trough. By early next week a broad
zone of southwesterly flow should exist downstream from the mean
trough axis. Leading energy moving into and through the West will
spread precipitation across the region and then bring a broad area
of various precip types to the central U.S. as its northeastward
ejection supports a Plains through Upper Great Lakes surface
system late Friday through the weekend. The trailing front may
become a focus for enhanced rainfall over parts of the
east-central U.S. late weekend into early next week. Below normal
temperatures will spread over an increasing portion of the
western/central U.S. with time while above normal temperatures
become more focused over the East.
...Guidance Evaluation/Predictability Assessment...
Guidance overall shows good agreement and continuity for the
expected large scale pattern evolution. Embedded smaller scale
system variances remains run to run inconsistent though, mainly
into days 5-7. The WPC medium range product suite was accordingly
derived from a composite blend of compatible guidance from the 06
UTC GFS and 00 UTC ECMWF/UKMET/Canadian days 3-5
(Thursday-Saturday) along with the 13 UTC National Blend of Models
(NBM). Blended the best compatible 06 UTC GFS/GEFS and 00 UTC
ECMWF/ECMWF ensemble means along with the 13 UTC NBM for days 6/7
(Sunday-next Monday) amid growing forecast spread, albeit in a
pattern with overall better than normal predictability. WPC
product continuity is well maintained in this manner.
...Weather Highlights/Threats...
The system moving into the West late this week will spread a broad
area of mostly light to moderate (though perhaps locally heavier)
rain and high elevation snow across the region. Some scattered
precipitation may persist over the West through the rest of the
period depending on shortwave details. Toward the end of the week
through the weekend precipitation should become more widespread
across the central U.S. as low pressure tracks from the central
Plains through the Upper Great Lakes. The best potential for
wintry precipitation types continues to extend from the northern
half of the High Plains into the Upper Great Lakes and eventually
New England. Highest probability of significant snowfall
currently exists over the Upper Midwest, just to the northwest of
the surface low track. There is still considerable uncertainty
over the strength of the system so confidence in the
precipitation/wind specifics is fairly low. Rainfall of varying
intensity will be possible over the rest of the
central/east-central U.S. ahead of the trailing cold front.
Guidance is signaling the potential for heavier rainfall within an
area from the southern Plains into the Ohio/Tennessee Valleys by
Saturday night/Sunday into Monday, as the front decelerates while
it becomes more aligned with flow aloft and interacts with low
level Gulf moisture. The northern fringe of this late-period
moisture shield could contain some wintry weather.
Late this week expect above normal temperatures from the
central/southern Plains through the Southeast, and including back
to the Great Basin/Southwest on Thursday. Highest anomalies
should be in the plus 15-25F range over the central Plains. On
the other hand the northern tier may see readings up to 10-20F
below normal. Colder air overspreading the West starting late
this week will continue to expand into the Plains during the
weekend into early next week, yielding a broad area of
temperatures 5-15F below normal by next Monday. Meanwhile the
eastern U.S. will see increasing coverage of warmer temperatures
Saturday-Monday, generally plus 10-20F anomalies for highs and up
to plus 20-25F anomalies for morning lows. Temperatures may
challenge record highs over the Southeast.
Rausch/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, 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