554 FXUS02 KWBC 160654 PMDEPD Extended Forecast Discussion NWS Weather Prediction Center College Park MD 254 AM EDT Thu Apr 16 2026 Valid 12Z Sun Apr 19 2026 - 12Z Thu Apr 23 2026 ...General Overview... A pattern change is expected across the eastern half of the country as a strong cold front heralds the end of the early season heat wave. Hot temperatures across the East Coast on Saturday will be replaced by a refreshing airmass by Sunday, and continuing into the start of next week as a Canadian surface high builds into the region. Out West, a new storm system arrives by Sunday and brings additional rain and mountain snow to the West Coast states. A broad upper ridge builds between the eastern U.S. trough and the West Coast system, but not to the same magnitude as what is currently in place across the country. ...Guidance/Predictability Assessment... There is generally good overall agreement in the 00Z guidance for the beginning of the forecast period Sunday across the Continental U.S., with a general model blend used for fronts and pressures. There are some placement differences with the upper low off the West Coast going into early next week, and recent runs of the GFS have been farther offshore, while the CMC/ECMWF guidance is indicating a solution closer to the coast. The 00Z GFS has trended closer to the model consensus with the eastern Canada/Great Lakes trough towards the middle of the next, whereas the previous run was likely too amplified with it. There has been a general higher trend with QPF across the Western U.S. as more moisture is advected inland from the Pacific compared to earlier forecasts. Overall, the NBM was a good starting point for temperatures, although winds were slightly lowered across the eastern Florida Peninsula on Monday into Tuesday, and PoPs were raised some across portions of southern California. The ensemble means were increased to about 40% by next Thursday. ...Weather/Hazards Highlights... A strong cold front reaching the East Coast Sunday/Day 4 is expected to be accompanied by a corridor of showers and some thunderstorms. Moderate to locally heavy rainfall is expected for the Northeast U.S. but appears to be progressive enough to limit the flood potential. However, a potential atmospheric river with the next Pacific storm system may produce enough rainfall across northern California to lead to some 1-2 inch rainfall on Sunday, and therefore a Marginal Risk area remains in place here. The same holds true for Monday/Day 5 with a Marginal Risk across portions of central/northern California. Mountain snow will also be commonplace for the higher terrain of the Sierra and the Cascades, and extending eastward to include for the northern Rockies. Portions of southern Texas may also see an increase in showers and storms early next week with a frontal boundary in the vicinity, but currently does not appear heavy nor widespread enough to merit any risk areas in the excessive rainfall outlook. The record breaking early season heat wave for many areas of the eastern U.S. will come to an end by Sunday as a strong cold front brings a return to much cooler conditions. The anomalous warmth is expected to be confined mainly to the coastal Carolinas and southward into Florida on Sunday before the entire East Coast gets relief on Monday. Conditions will turn rather chilly from Michigan to New England with highs mainly in the 40s to lower 50s, and frost/freeze conditions Sunday and Monday nights. The central and southern Plains heat back up as highs reach well into the 80s from western Texas to Nebraska by Tuesday, and this warmth then spreads eastward again to the Mid-Atlantic and Southeast U.S. with highs from the middle 70s to the middle 80s by Wednesday, but less extreme compared to the hot temperatures in the short range period. Hamrick Additional 3-7 Day Hazard information can be found on the WPC medium range hazards outlook chart at: https://www.wpc.ncep.noaa.gov/threats/threats.php WPC medium range 500mb heights, surface systems, weather grids, quantitative precipitation forecast (QPF), excessive rainfall outlook (ERO), winter weather outlook (WWO) probabilities, heat indices, and Key Messages can be accessed from: 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/#page=ero https://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4 https://www.wpc.ncep.noaa.gov/heat_index.shtml https://www.wpc.ncep.noaa.gov/#page=ovw $$