Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
247 PM EDT Tue Oct 01 2019
Valid 12Z Fri Oct 04 2019 - 12Z Tue Oct 08 2019
...Guidance/Uncertainty Assessment...
The WPC medium range product suite was primarily derived from a
composite blend of well clustered solutions from the 06 UTC
GFS/GEFS and 00 UTC ECMWF/ECMWF ensembles. This solution maintains
good WPC continuity for much of the forecast period in a pattern
with seemingly above normal forevcast predictability.
...Weather Pattern Highlights/Threats...
An amplified upper trough works over the West Friday as a northern
stream upper trough clears the Northeast well downstream. A
surface low pressure system moving pass New England then will
bring focused rainfall to areas near/north of the low track.
Rainfall along the trailing front will diminish except for some
activity persisting over the southern Rockies/High Plains where
the front stalls. The western U.S. upper trough and developing
surface system progresses across the Rockies and into the Plains
to bring scattered rain/high elevation snow to northern parts of
the West late week and areas of locally moderate to heavy rain
over the central U.S. this weekend. Enhanced rains will reform
eastward with frontal progression/moisture pooling and dynamic
support aloft through the Appalachians/Northeast and vicinity
later weekend into early next week. The forecast becomes more
uncertain early next week given pre-frontal flow differences that
will determine frontal timing/waviness and how much moisture may
flow northward from the Gulf of Mexico. WPC progs now show a more
progressive front than continuity, but there remains potential for
some significant Southeast rains even with discount of the wetter
Canadian model guidance after collaboration with NHC.
Record warmth over the eastern and southeastern U.S. should
largely come to an end on Friday behind a cold front. Meanwhile,
expect unseasonably cool readings over the Northwest (10-20F below
normal) to persist late this week and then trend closer to normal
over the Pacific Northwest followed by the northern Rockies.
Schichtel
Additional 3-7 Day Hazards information can be found on the WPC
medium range hazards chart at:
https://www.wpc.ncep.noaa.gov/threats/threats.php
Hazards:
- Heavy rain across portions of the Central Plains, the Middle
Mississippi Valley, and the Upper
Mississippi Valley, Sat, Oct 5.
- Flooding possible across portions of the Central Plains, the
Northern Plains, the Middle
Mississippi Valley, the Upper Mississippi Valley, the Great Lakes,
and the Ohio Valley.
- Flooding occurring or imminent across portions of the Central
Plains, the Middle Mississippi
Valley, the Great Lakes, and the Northern Plains.
- Flooding likely across portions of the Central Plains, the
Middle Mississippi Valley, and the
Upper Mississippi Valley.
- Much above normal temperatures across portions of the Southeast,
Fri, Oct 4.
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