Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
1200 PM EDT Fri Oct 04 2019
Valid 12Z Mon Oct 07 2019 - 12Z Fri Oct 11 2019
...Another round of cold/snow for the Northern Rockies next week...
...Guidance/Uncertainty Assessment...
The WPC medium range product suite was mainly derived from a
composite blend of quite well clustered guidance from the 06 UTC
GFS along with 00 UTC ECMWF/UKMET/Canadian and National Blend of
Models Mon into Wed when forecast confidence remains above normal.
Blended the 06 UTC GFS/00 UTC ECMWF and their respective ensemble
means by Thu-Fri at these longer timeframes that offer less
stellar run-run continuity with small-mid scale timings/amplitudes
of systems embedded within the larger scale flow pattern.
...Weather Highlights/Threats...
A lead and cooling cold front and supporting upper trough to
approach the East Coast Mon will provide a focus for some locally
modest-heavier rainfall from the central Appalachians into the
Northeast. Rainfall should be mainly beneficial over areas
currently experiencing drought of varying intensity. By Tue-Fri
the front settles over the Florida Peninsula and possibly lead to
some rainfall enhancement in its vicinity.
Upstream, an amplifying upper trough set to dig southeastward from
the Gulf of Alaska will bring a period of rain and initially
higher elevation snow to the Northwest U.S. during the first half
of next week with highest totals over favored westward-facing
terrain. WPC Winter Weather Outlook snowfall probabilities are
near 70% (> 2-3" snow) over higher elevations on Tuesday in
western Montana around Glacier Park. The cold air behind the
leading surface front will progress southward and eastward which
will lower snow levels toward or into the valley locations of the
rest of Montana. High temperatures are likely to be at least
10-20F below average over the northern Rockies/Plains on Wed and
over much of the northern-central Plains by Thu. This will spread
southward to Texas and eastward to the Mississippi Valley by
Friday but perhaps with less intensity. Rainfall will expand and
offers a risk to become locally heavy from the south-central
Plains to the mid-MS Valley/Midwest later in the period with
moisture inflow return from the Gulf.
Fracasso/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
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