108 FXUS02 KWBC 131748 PMDEPD Extended Forecast Discussion NWS Weather Prediction Center College Park MD 148 PM EDT Mon Apr 13 2026 Valid 12Z Thu Apr 16 2026 - 12Z Mon Apr 20 2026 ...Hot across the East Coast and more heavy rain and thunderstorms for the Plains and Midwest to close out the work week... ...General Overview... An anomalous upper level ridge will be in place across the Eastern U.S. for the end of the week, accompanied by record breaking temperatures in many places from the Carolinas to the Mid-Atlantic. A lead shortwave crossing the Ohio Valley and the Northeast will put a dent in this ridge, followed by a much stronger trough/cold front by Sunday that will bring the early season heatwave to an end. This same storm system will likely generate multiple rounds of heavy rain and strong to severe thunderstorms across the Plains and Midwest, followed by a return to much cooler weather. A new storm system from the Pacific is likely to affect the West Coast region by Sunday into Monday with renewed prospects for rain and mountain snow across much of the region. ...Guidance/Predictability Assessment... Overall decent model agreement of the amplified upper-level trough over Western U.S. gradually moving eastward through the earlier portion of the period. As we head into the weekend, deterministic models start to diverge and show an increase in run-to-run variability on the shortwave energy ejecting from the West. The most noticeable outlier will be the GFS, as it shows a faster progression of the large-scale features, especially for the Low pressure system evolving off the Pacific Northwest on Sunday. Later in the period, models spread increases even further, which made fine-tuning difficult. Therefore, the latter portion of the forecast incorporated much more of the model means. In addition, the NBM seemed to under-perform on temperatures over the Southeast/Mid- Atlantic through Sunday. ...Weather/Hazards Highlights... The lead shortwave trough crossing the Ohio Valley on Thursday is expected to be accompanied by a weakening band of showers and thunderstorms from the Mid-South to the Ohio Valley. Most of the guidance does not currently show anything all that concerning from a flood potential perspective, and therefore the Day 4/Thursday excessive rainfall outlook remains void of any risk areas, although this could change in the days ahead as the smaller scale details of any concentrated thunderstorm activity becomes more in focus. The larger scale trough and front approaching the Midwest on Day 5/Friday will have enough dynamics and instability to support more widespread convective coverage and heavy rainfall from eastern Kansas to the greater Chicago metro area, and therefore a Marginal Risk area will be valid here for Friday. Winter weather will continue to make weather headlines across the higher terrain of the western U.S. in two distinct rounds. The amplifying trough over the northern Rockies will support moderate to heavy snow from northern Utah/Colorado northward to the Idaho and Montana Rockies Thursday, with up to a foot of snow likely for the higher ranges. There will be a break in the action until late Saturday when the next storm system arrives in the Pacific Northwest. This is forecast to produce heavy snow for the Cascades and extending to the northern Sierra by Monday morning, and showers for the lower elevations and near the coast. The anomalous and record breaking April heatwave will still be ongoing going into the start of this forecast period Thursday from the Plains to the East Coast, with the greatest anomalies expected from Virginia to Georgia. Widespread lower to even middle 90s are expected Thursday, which would set numerous daily records and perhaps come close to some monthly records. This also holds true going into Friday and Saturday as well, although northern portions of the Mid-Atlantic may get a modest cooling trend with a weak frontal boundary dropping south. Relief comes by Sunday as a strong cold front steadily makes its way to the East Coast, with the hottest conditions mainly confined to the Piedmont and coastal plain of Virginia and the Carolinas, and then pleasantly cooler by Monday with the front exiting the coast. Oudit/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 $$