Extended Forecast Discussion NWS Weather Prediction Center College Park MD 307 PM EDT Sat Oct 11 2025 Valid 12Z Tue Oct 14 2025 - 12Z Sat Oct 18 2025 ...Locally heavy rain and flash flooding remain a threat for parts of the Southwest next week... ...Heavier rain and mountain snow for California... ...Overview... An amplified pattern will favor a stormy period for much of the West with well below temperatures. This will bring modest rain to California and significant snow for the Sierra on Tuesday (especially above 6500ft). This will spread across the Intermountain West midweek and perhaps linger through much of the week as the system slowly moves eastward/northeastward. Over the central and eastern states, the coastal storm in the short term will pull away from the Northeast and milder air will be prevalent as upper ridging builds ahead of the western troughing. ...Guidance/Predictability Assessment... For the first half of the period, the models remained in good agreement and multi-model blend sufficed as a starting point. By around Thursday, there was a notable divergence of opinion in how quickly to lift the western trough: most dynamical models were quicker while the AI models/ensembles were slower. The previous/overnight shift was nicely in between the two camps, and have favored continuity for next Fri/Sat for now. The flow is somewhat complicated by incoming northern stream shortwaves later in the week next week which could modulate the shape/axis of the trough or split it into multiple shortwaves. The 13Z NBM was the basis for the sensible weather grids but with modification by next Fri/Sat to account for the slower preference. In the central/eastern states, a slower western trough would delay the ridge axis from moving eastward but again this could be complicated by northern stream shortwaves through eastern Canada. Confidence in the forecast started above average with a trend to near/below average by the end of the period. ...Weather/Hazards Highlights... Over the Northeast, the coastal storm and its effects (blustery winds, high surf, and above normal tides) will pull away from the coast at the start of the period. Focus will be on the West as the incoming upper low that will bring in the rain/snow to California will be underway on Tuesday. A Marginal Risk in the Excessive Rainfall Outlook is noted for areas between San Francisco and Los Angeles. Heavy snow is likely in the Sierra above 6500-7000ft. In addition, another Marginal Risk area exists over New Mexico where moisture levels remain high. Into Wednesday, the system will continue southeastward and push the rain/snow into the Intermountain West, with a continued threat over New Mexico where another Marginal Risk area is in place. Much of the West will see at least some rain or snow, with snow levels lowering as colder air moves in. Temperatures will be well below normal Tue-Wed (by 10-20 deg) with some slight moderation for the rest of the week, but still staying cooler than normal. For the central states, southwesterly flow will increase the chances of light to modest rain late Tuesday into Wednesday over the Northern Plains into the Upper Midwest closer to the jet stream. However, mild and moisture-laden air to the south (central to southern Plains) will support at least isolated showers and perhaps some storms ahead of the western/Rockies system. Much of the Southeast will remain dry and warm through the period with temperatures well into the 80s and low 90s (South TX). Fracasso 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