Extended Forecast Discussion NWS Weather Prediction Center College Park MD 1159 AM EDT Tue Oct 22 2019 Valid 12Z Fri Oct 25 2019 - 12Z Tue Oct 29 2019 ...Overview and Guidance/Uncertainty Assessment... Amplified pattern to continue into next week but with muted confidence later this week. Majority of the ensemble/deterministic guidance continue to forecast a splitting of the flow just east of the Rockies which will likely result in a slowly moving closed low over New Mexico/Texas late this week that would get picked back up into the flow ahead of another incoming trough through the Northwest. The GFS has remained the quickest model for several cycles but even the GEFS ensembles have trended slower in the past 24 hrs. The ECMWF ensembles remain slower than the GEFS and the Canadian ensembles were quite varied (some as slow as the slowest ECMWF members but others as quick as just behind the GFS). With an increased number of ECMWF members and the continued agreement of the ECMWF/Canadian and UKMET (though the UKMET was in between the ECMWF/GFS), opted to continue to favor the slower camp but not as slow as the ECMWF/Canadian. By next Sun-Tue, amplification downstream of a strong Alaskan storm should favor another trough digging just east of southward through the Pac NW and Great Basin. Ensembles were in much better agreement here with more typical differences between the GEFS (a bit weaker/farther east) and the ECMWF ensemble mean (a bit deeper and farther west). Again favored the ECMWF ensembles given the lead-in pattern and its typically better handling of amplified flow over the GEFS. ...Weather Highlights/Threats... With a favored slower evolution over the Southern Plains/Lower MS Valley, this allows for a longer and continued fetch of moisture influx out of the Gulf and over the front. Several inches of rain are possible from the NW Gulf northward through Louisiana/Arkansas as a weak wave of low pressure slows the front through the mid-South. The boundary should slowly push northeastward through the Ohio Valley this weekend and weaken as it encounters ridging to its east and as a stronger front to its west largely absorbs/overtakes it. In the West, incoming cold front late this week into the weekend will be mostly cut off from the moisture supply but will still manage to spread light to perhaps moderate precipitation out of Montana through Wyoming. Temperatures will trend much colder than average in the West behind the lead cold front this weekend, with max temperatures 10-25 deg F below average Sunday into next Tuesday along/east of the Divide from western Montana to eastern Colorado as the front whooshes southward. Above average temperatures will be confined to the Southeast to the south and east of the front. Florida will continue to see high temperatures well into the 80s with some record highs possible this weekend. 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