Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
200 AM EST Sat Feb 16 2019
Valid 12Z Tue Feb 19 2019 - 12Z Sat Feb 23 2019
...Multi-day Threats of Heavy Rain for the Lower
Mississippi/Tennessee Valleys to South-Central Appalachians and
Ohio Valley/Northern Mid-Atlantic Heavy Snow/Ice...
...Western to Central U.S. Cold/Unsettled Weather to focus into
the Southwest...
...Guidance/Predictability Assessment and Weather Hazards...
Models and ensembles maintain a pattern with a series of potent
upper troughs/height falls progressing overtop a northeast Pacific
ridge that then dig sharply southward to reinforce a western US
mean trough. The supports Western to Central U.S. cold/unsettled
weather with a focus over the Southwest. Lead deep layered and
anomalously moist southwest flow channeled from the southern
Plains to the East meanwhile acts to sustain a Southeast ridge and
fuel multi-day threats of heavy rain/training from the Lower
Mississippi/Tennessee Valleys to South-Central Appalachians and
Ohio Valley/Northern Mid-Atlantic Heavy Snow/Ice. This occurs as
multiple waves traverse a lingering southern to eastern U.S. front.
In this pattern main mid-upper level troughs eject from the
Southwest to Northeast Tue-Thu as a main upstream trough digs from
the Pacific Northwest to the Southwest Wed-Sat. This amplified
pattern overall offers above normal forecast predictability next
week, albeit with timing/strength variance with embedded small-mid
scale systems growing gradually over time. The WPC medium range
product suite was primarily derived from a composite blend of well
clustered guidance from the recent GFS/ECMWF and GEFS/ECMWF
ensemble means along with the National Blend of Models and WPC
continuity.
Schichtel
WPC medium range 500mb heights, surface systems, weather grids,
quantitative precipitation and winter weather outlook
probabilities are found 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