Extended Forecast Discussion NWS Weather Prediction Center College Park MD 109 AM EST Thu Jan 23 2020 Valid 12Z Sun Jan 26 2020 - 12Z Thu Jan 30 2020 ...Overview... Upper ridging over Hudson Bay and between Hawai'i and California will favor troughing settling into the central CONUS. This will further be reinforced by upper troughing over Alaska. This configuration will lead to near to above normal temperatures nearly CONUS-wide, especially east of the northern Rockies across the High Plains and into the Upper Midwest, and wetter than average for the Pacific Northwest as a series of storms push through. Lighter precipitation is expected east of the Rockies during the middle of next week. ...Guidance/Predictability Assessment... Exiting Northeast system continues to show good clustering, but that cluster continues to drift with each model cycle (generally quicker and bit farther west). Ensemble mean consensus was surrounded by the deterministic runs, so the blended solution was still preferred. To the south, old frontal boundary will carry a surface wave through the Gulf Monday with some enhanced rainfall for Florida, but perhaps just confined to the southern portions/Keys. 18Z GFS and 12Z ECMWF clustered fairly well. In the West, confidence remains below average due to the progressive flow due to the fast jet (150-170kts) shifting past the Dateline. Multiple shortwaves aloft will carry surface fronts into WA/OR/BC, some of which will retain their identity through and past the Rockies. The first, on Monday, should focus its development over the southern Plains on Tuesday. 18Z GFS and 12Z ECMWF were closer to each other than the 12Z GFS or Canadian, and this was used with a blend of the ensemble means since the previous runs have not been consistent. This low is forecast to lift northeastward next Thursday. Other systems out of the Pacific may get wrapped up toward the Gulf of Alaska and/or weaken once onshore. Trend toward half ensemble weighting also helped here to maintain relatively good continuity in an otherwise low-predictability pattern. ...Weather/Hazard Highlights... A wave crossing the Gulf of Mexico may bring a brief period of enhanced rainfall to the extreme northern Gulf Coast Sunday but then perhaps more likely across South Florida and the Keys Monday. Amounts will be contingent on exact evolution, which could keep appreciable rain just off the coast. Teleconnections relative to the Alaska/Northeast Pacific pattern provide good support for the significant totals of rain/mountain snow expected over the Pacific Northwest and northern California during the period. Some locations along favored Cascades and coastal terrain may see at least 5-10 inches liquid for the five-day period. Day-to-day specifics have much lower confidence due to low predictability of supporting shortwaves embedded within progressive mean flow. Lighter precipitation is forecast across portions of the Interior West and northern-central Rockies. The system expected to affect the Plains into east-central U.S. early-mid week should bring an area of rain south/snow north. Gulf inflow may be low after the lead-in system Monday but some modest amounts are possible. The Northeast will see a dry week after the surface low pulls away on Sunday. The forecast pattern will promote near to above average temperatures over most of the lower 48 during the period. Highest anomalies will likely be across the northern tier states which should average 10-20F above normal for highs and 15-25F above normal for morning lows. The best possibility of near to modestly below normal readings will be over the Southeast/Florida as well as the central-southern Rockies. 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