Extended Forecast Discussion NWS Weather Prediction Center College Park MD 1032 AM EST Tue Nov 12 2019 Valid 12Z Fri Nov 15 2019 - 12Z Tue Nov 19 2019 ...Pattern Overview and Guidance/Predictability Assessment... Upper ridging on either side of North America will favor a series of troughs progressing across the CONUS. For days 3-4, an upper trough crossing the southeast causes low pressure to develop just off the Southeast coast and move northeastward to off the Mid Atlantic coast by day 5 and off the New England coast days 6-7. Models cluster in 2 camps, with the GFS/GEFS Members/Canadian slightly faster in moving the low northeast and the ECMWF/ECMWF mean/00z UKMET slower. A blended solution is proposed to mitigate the timing differences. A Western trough on Friday will progress across the northwest and northern Rockies and then the northern Plains Sat and into the upper Great Lakes/mid MS Valley Sun 17 Nov. The southern portion of the trough amplifies over western Gulf states Sun night-Mon with low pressure developing over the Gulf and continuing a slow east movement on Tue, with a wave of low pressure along the front traversing Florida. The next wave crossing the northern Pacific toward the Pacific northwest is poised to approach or move onshore Monday 18 Nov. The last couple of runs of the ECMWF showed a closed low developing within the wave (just off the northern Ca/Southern OR coast 12z Tue 19 Nov), but most ECMWF and GEFS ensemble members show an open wave persisting. The operational progs blended the operational run with the operational GFS and respective 00z ECMWF and 06z GEFS ensemble means and show an open wave until more solutions show the closed low developing. ...Weather Highlights/Threats... Below average temperatures in the East will slowly moderate back toward more typical mid-November values by early next week. Much of the West will have temperatures above normal by 5-15 degrees through this weekend, moderating early next week with the arrival of the next upper trough. The system in the southeast to mid Atlantic coastal waters should keep the heaviest rains offshore but is close enough to produce showers in coastal areas. The strong pressure gradient between the low and mid 1030s high over New England leads to windy conditions along the southeast to the mid Atlantic coasts. The precipitation shield will move northward into New England early next week. Several systems out of the Pacific will maintain a rather wet period for at least coastal Washington/Oregon and the Cascades, with less rain/snow along and just west of the Continental Divide. Petersen/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