Extended Forecast Discussion NWS Weather Prediction Center College Park MD 219 AM EDT Thu Apr 02 2020 Valid 12Z Sun Apr 05 2020 - 12Z Thu Apr 09 2020 ...Overview and Guidance/Predictability Assessment... An upper low is forecast to dig southward along the California coast next week and slowly move into the Four Corners region. Wave northern stream flow east of the Rockies will transition toward increased troughing via the northern stream toward the Great Lakes. The models/ensembles show good agreement for the Sun-Tue period overall and a deterministic blend sufficed as a starting point. For next Wed-Thu, the 12Z and especially the 18Z GFS were quicker to move the upper low out of Southern California compared to the 18Z GEFS mean and 12Z ECMWF/ECMWF ensemble mean (12Z Canadian was even slower). Given the slowing trend over the past couple of days, favored the slower ECMWF-led consensus but did not discount the GFS completely as the ECMWF/Canadian can be too slow with closed systems. To the north, ensembles showed more agreement on a respectable upper low moving through Ontario but with continued spread in the members. ...Weather/Hazard Highlights... Focus for precipitation will be in the West, particularly California/Nevada, with locally heavy rain in the coastal ranges with southwestern exposure and over the Sierra Nevada (heavy snow). To the east, a frontal boundary over Texas will help instigate showers and some storms as it lifts back to the north as a warm front late Sun into Mon then into the Great Lakes by Tue. Modest rainfall amounts are possible in the southern MS Valley/Southeast. Temperatures will be cooler than normal in the West (especially California) with max temp anomalies of -5 to -15 deg F (highs in the 50s/60s generally with some 70s inland). By contrast, much of the East will see well above normal temperatures, especially south of the warm front, into the 80s within a few hundred miles of the Gulf Coast. Some record highs are possible from Louisiana eastward to Florida (Tue-Thu). Northern cold front next Wed/Thu is forecast to bring in cooler air from Canada but only back to typical April levels. 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