Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
219 AM 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...
Upper pattern will be driven by ridging over southwestern Canada
which supports broad troughing in the eastern half of the lower
48. A robust central-eastern system will exit off the east coast
late Friday into Saturday (but linger in south Florida) as the
pattern will turn much quieter by next Sunday/Monday. The
models/ensembles 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.
...Weather Highlights and Hazards...
Low pressure over Iowa Thursday morning will bring wind-driven
snow to 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.
Fracasso
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