Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
318 PM EST Wed Nov 06 2019
Valid 12Z Sat Nov 09 2019 - 12Z Wed Nov 13 2019
...Strong Cold Front Includes Northern Tier to Northeast Snows
Early Next Week...
...Pattern Overview and Guidance/Predictability Assessment...
The larger scale flow pattern is expected to remain amplified into
next week with a U.S. West Coast to Alaska ridge and downstream
trough over the central/eastern CONUS. Overall, forecast
confidence in the large scale pattern is decent, but breaks down
toward the midweek as troughs of uncertain timing push into the
West Coast. The 00Z UKMET had strength/timing issues with the lead
cold front and is excluded from the blend. The 00Z/06Z GFS are
much slower than the 00Z ECMWF/CMC with the first trough pushing
through the western ridge by Day 5. The preferences was toward the
00Z ECMWF/CMC into Day 5, then a strong switch to the 00Z
ECENS/NAEFS means for Days 6/7 for pressures and fronts.
...Weather Highlights/Threats...
An Arctic-sourced cold front pushes south from Canada, reinforcing
the mean eastern trough, this weekend, bringing colder than normal
temperatures for the eastern 3/4 of the CONUS. The center of the
surface high pressure centers tracks south/southeast from the
Canadian Prairies and across the center of the CONUS into the
middle of next week. A lead airmass will cross the central/eastern
states by Sat with a fairly broad coverage of temperatures 10-20F
below normal that could produce a few record cold values. Then by
Sun-Wed an even colder surge with highs 15-25F below normal is
expected to spread across the central and eastern U.S. that may
produce more widespread record cold temperatures.
A lead weekend clipper system and trailing cold cyclonic flow will
bring mostly snow to the Great Lakes/Northeast with snows
prolonged into next week by lake effect. Meanwhile, locations
along the eastern slopes of the northern-central Rockies will see
periods of enhanced snows as the trailing Arctic front digs
southward resulting in upslope flow. The longwave upper flow
pattern continues to suggest potential for low development off the
East Coast early-mid next week, although there remains uncertainty
in its coastal proximity and extent of potential wintry impacts.
Guidance continues to show support for another threat of some
heavy snow for the Northeast and vicinity.
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
- Heavy precipitation across portions of the Northeast, Tue, Nov
12.
- Heavy rain across portions of the Western Gulf Coast, Mon, Nov
11.
- Heavy snow across portions of the Upper Great Lakes, Mon, Nov 11.
- Flooding possible across portions of the Lower Mississippi
Valley and the Southern Plains.
- Flooding occurring or imminent across portions of the Middle
Mississippi Valley, the Lower Mississippi Valley, and the Northern
Plains.
- Flooding likely across portions of the Northern Plains.
- Much below normal temperatures across much of the Central and
Eastern U.S., Mon-Wed, Nov 11-Nov 13.
- Much below normal temperatures across portions of the
Mid-Atlantic, Sat, Nov 9.
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