Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
429 PM EDT Mon Mar 11 2019
Valid 12Z Thu Mar 14 2019 - 12Z Mon Mar 18 2019
...Heavy snow/wind threat to exit the North-Central U.S.
Thursday...
...Heavy rain threat in the Southeast Thursday...
...Overview and Guidance Assessment/Preferences...
The ridging over the western U.S. and Canada will support the
trough persisting over the eastern half of the CONUS over the
course of this coming week. A robust winter storm system will lift
northeast from the Central Plains through the Great
Lakes/Northeast by late Friday. The trailing flank of this frontal
boundary will stall and linger over South Florida and the Gulf of
Mexico. A series of systems will track through the Gulf of
Alaska/North Pacific and weaken as they approach the Pacific
Northwest Coast.
The models/ensembles continue to show reasonable clustering
through the period and a blend of the GFS/ECMWF with their
ensemble means offered a good starting point that kept in line
with continuity. The CMC and its ensemble means were largely
discounted for much of the extend periods as it initialized well
to the north/northwest of the rest of the cluster.
...Weather Highlights and Hazards...
Low pressure over Iowa Thursday morning will bring strong, gusty
winds that will cause blowing and drifting snow across the Upper
Midwest and then Great Lakes as it exits through Ontario and
Quebec on Friday. To the south, influx of Gulf moisture will
support a continued threat for heavy rainfall and embedded
convection from Alabama/Mississippi eastward as the cold front
continues to move eastward and southward. Mild air drawn northward
ahead of the front will be replaced by much cooler temperatures
(5-10 degrees below average) that will finally exit out of the
west and focus on the central states. By Sat-Mon, high pressure
will be in control of much of the lower 48 with a dry northwest
flow out of Canada, supporting some lake-enhanced snows.
...Bullet points from Medium Range Hazardes Chart...
- Heavy rain across portions of the Southeast, the Mid-Atlantic,
the Southern Appalachians, and the Tennessee Valley, Thu-Fri, Mar
14-Mar 15.
- Heavy snow across portions of the Central Plains, the Upper
Mississippi Valley, and the Northern Plains, Thu-Fri, Mar 14-Mar
15.
- Flooding possible from portions of the Plains to the Great
Lakes, and the Middle/Upper Mississippi Valley.
- Flooding occurring or imminent across portions of the Central
Plains, the Lower Mississippi Valley, the Tennessee Valley, the
Middle Mississippi Valley, the Southeast, and the Ohio Valley.
- Flooding likely across portions of the Central Plains, the
Middle Mississippi Valley, and the Upper Mississippi Valley.
- High winds across portions of the Central/Northern Plains, and
the Upper/Middle Mississippi Valleys, Thu, Mar 14.
- Much below normal temperatures across portions of the High
Plains, the Central/Southern Rockies, Thu-Sun, Mar 14-Mar 17.
Campbell
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