Extended Forecast Discussion NWS Weather Prediction Center College Park MD 253 AM EDT Tue Mar 15 2022 Valid 12Z Fri Mar 18 2022 - 12Z Tue Mar 22 2022 ...Overview... A relatively progressive flow pattern with increasing amplitude is expected to be in place across the continental U.S. through the upcoming weekend. The initial system over the Central Plains Friday will be tracking northeastward to the Great Lakes and then the Northeast through Sunday. By late in the weekend to next Monday, a much stronger and amplified trough will progress across the western U.S., and then reaching the Plains by late Monday and into Tuesday, with the overall pattern becoming a bit less progressive by then. This will likely bring widespread, beneficial rains to the western U.S., and evolve into a potentially strong storm system by the end of the forecast period. No significant arctic air intrusions are currently expected, and temperatures will generally oscillate between near normal and well above normal ahead of the various waves of low pressure. ...Guidance Evaluation/Predictability Assessment... Overall, the 12Z model guidance suite indicates good synoptic scale agreement on the main features of interest, including the large upper level trough developing over the Intermountain West and then the Plains early next week. However, it is worth noting that the past few runs of the GFS have been to the northwest of the model consensus with the surface low tracking across the Ohio Valley and Great Lakes region during the Friday to Saturday time period, with the latest run edging closer to the preferred ECMWF/CMC/UKMET cluster of solutions. The GFS is also slightly stronger with the amplifying western trough, but similar in regard to timing. The associated surface low that evolves over the Central Plains will likely be on the stronger side of the model guidance, and the GFS probably captures the intensity best compared to the slightly weaker CMC/ECMWF solutions. ...Weather Highlights/Threats... The next system moving across the Plains could bring some moderate to locally heavy rainfall as well as potential winter weather on the northwest/cold side of the low, though the aforementioned model differences and marginally supportive thermal profiles for winter weather will keep the latest Winter Weather Outlook for Day 4 generally low. Finally, the active/unsettled weather for the western U.S. toward the end of the weekend and early next week will be mostly beneficial and welcomed precipitation across drought stricken areas. There will be the potential for heavy rain to develop across portions of the Southern Plains early next week as this storm system taps into increasing Gulf moisture. Temperatures look to be mostly near to above normal, ahead of the various waves of low pressure. Some dips to below normal readings are possible across the West and interior West as the next large scale weather system moves through owing to clouds and precipitation. Hamrick 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 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