Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
1203 PM EDT Wed Oct 02 2019
Valid 12Z Sat Oct 05 2019 - 12Z Wed Oct 09 2019
...Overview and model uncertainty assessment...
Global deterministic guidance has variability in the pattern
beginning this weekend with the strength of the ridge up the BC to
AK coast and the downstream north-central CONUS trough ejecting
northeast across the western Great Lakes. The ECMWF remains more
amplified than other guidance both this weekend and into the
middle of next week for all troughs and ridges over North America.
The strong ridging over the Aleutians has a teleconnection
favoring a multi-day mean of ridging over the eastern CONUS, so
the operational 00Z ECMWF was limited starting on Day 5 in favor
of ensemble means.
Another area of uncertainty is an upper trough approaching the
Pacific Northwest Tuesday into Wednesday. The ECMWF continues to
favor an upper low to form near the shore while the GFS is much
more progressive with an open trough pushing inland. As the 06Z
GFS/GEFS was even more progressive with this feature than the 00Z,
the 00Z NAEFS was used. The WPC forecast package was primarily
derived from a composite blend of the 06Z GFS and the 00Z ECMWF
through Day 4 with increasing weight on the 00Z ECENS and NAEFS
means for Days 5 to 7.
...Weather Pattern Highlights/Threats...
A cold front progresses from the Plains to across the Midwest
Saturday into Sunday before slowing down and not reaching the East
Coast until Monday night. This slowing causes an increased chance
for heavier rain to linger across the Tennessee Valley into the
Northeast. A decrease in forcing looks to bring more general rain
through the East Coast Monday.
Record high temperatures will be limited to the Deep South by
Saturday as a cold front progresses east while well below normal
temperatures spread in behind the front. The western U.S. upper
trough will bring scattered rain/high elevation snow to the
Pacific Northwest and northern Rockies Monday into the middle of
next week. Meanwhile, tropical moisture will bring a good chance
of thunderstorms across Florida starting Monday. The heaviest
rains are expected to stay in the Gulf of Mexico through the
middle of next week.
Jackson
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
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