Preliminary Forecasts
Issued by NWS
Issued by NWS
264 FXUS02 KWNH 130756 PREEPD Preliminary Extended Forecast Discussion NWS Weather Prediction Center College Park MD 355 AM EDT Mon Oct 13 2025 Valid 12Z Thu Oct 16 2025 - 12Z Mon Oct 20 2025 ...Guidance/Predictability Assessment... Medium-range guidance still shows reasonably good mid-larger scale agreement on an amplified pattern evolution initially highlighted by a western U.S. deep trough and a downstream building/warming ridge set to slowly shift from the central to eastern U.S.. This translation occurs with advent of another amplified upper trough/low slated to breach the West Coast in about a week. Forecast spread seems manageable for Thursday/Friday and a 18 UTC GFS and 12 UTC ECMWF/UKMET/Canadian model blend seems fine. Opted to then switch to an ensemble mean blend by the weekend amid pesky enbedded system and stream separation variances. Leaned more heavily on the ECMWF ensemble mean whose somehwat more amplified solution seems to best fit the ongoing amplified pattern. This solution also maintains good continuity with the previous WPC forecast and the latest 00 UTC model trends are quite favorable. ...Weather/Hazards Highlights... A current coastal storm is expected to be working well out to sea across the western Atlantic by Thursday, but should still support continued unsettled/windy conditions over New England through late week as enhanced as impulses dig on the backside of the storm. An upper low/amplified trough impacting the West over the next few days will work over the Rockies to increasingly effect the north- central U.S. mid-late week to include increasing chances of rain with wavy surface system translation. More moisture-laden air to the south over the central Plains and Mid-Mississippi Valley will support a growing pattern with showers and heavier thunderstorms. Activity may flourish as focus shifts slowly into the east-central U.S. states into next weekend in an emerging return flow pattern to monitor for enhanced rainfall and runoff issue potential. Later period, the upstream signal continues to grow in support of approach of an amplified Northeast Pacific storm system to the Pacific Northwest/West Coast next weekend to offer unsettled flow and enhanced precipitation threat to monitor. Schichtel 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 $$