Extended Forecast Discussion NWS Weather Prediction Center College Park MD 233 AM EDT Mon Mar 30 2020 Valid 12Z Thu Apr 02 2020 - 12Z Mon Apr 06 2020 ...Overview... An upper low initially over western Canada will slowly translate eastward toward central Canada as another upper low east of New England on Thursday moves into the Atlantic. This will allow ridging to build into the Great Lakes and to the East Coast by the weekend. An extremely strong upper high over far northern Canada (500mb heights about +3.5 sigma) in addition to one over the Aleutians support the maintenance of this pattern into next week. ...Guidance/Predictability Assessment... Multi-day trends in the guidance appear to be settling down from a rather chaotic few runs. Still, agreement seemed transient as the deterministic models have, in some form or another, acquiesced toward the ensembles or cluster of ensembles (when a bifurcation in the members occurred) leaving forecaster confidence no better than average. A blend of the 12Z/18Z guidance to start offered reasonable clustering with the Plains system slowly but steadily advancing eastward (trend has been notably slower). Incoming Pacific system Friday will push inland though the 12Z ECMWF had a potentially spurious backside low dropping southward just off the CA coast next Sunday which was not preferred. By that point, preferred a supermajority ensemble weighting as the eastern system may dissipate and another drapes itself over the High Plains/Northwest. ...Weather/Hazard Highlights... Precipitation will focus in two areas along/ahead of the frontal system moving through the Plains Thu-Fri: 1) S Texas eastward along the I-10 corridor and 2) along the track of low pressure from Kansas to Minnesota. Marginally cold air on the northwest side of the low, especially over eastern Montana into the Dakotas, would support a swath of several inches of snow Thu-Fri. Precipitation will become lighter farther east by the weekend as upper ridging only slowly relents. Pac NW will see some light rain/snow as a couple systems move through the region. Area of cold temperatures (10-25 deg below normal) will move out of Montana and moderate behind the cold front. Slightly cooler temperatures (5-10 deg below normal) will spread through the Plains Fri-Sat. Milder temperatures initially over NM/TX (ahed of the front) will proceed eastward to the East Coast next week. 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