Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
117 AM EST Tue Feb 19 2019

Valid 12Z Fri Feb 22 2019 - 12Z Tue Feb 26 2019

...Multi-day heavy rainfall/flooding threat from the Lower
Mississippi/Tennessee/Ohio Valleys to the Southern/Central
Appalachians through Saturday...

...Significant heavy snow/ice threat lifts from the Southwest and
south-central Rockies states Friday through the Plains/Upper
Midwest and Great Lakes/Northeast this weekend...


...Pattern Overview and Weather Highlights/Hazards...

A favorable corridor for a multi-day heavy rain/training episode
will persist from the lower MS/TN/OH Valleys to the Srn/Central
Appalachians and Mid-Atlantic through Sat. Flooding/runoff issues
will be fueled by highly anomalous moisture channeling into a wavy
frontal zone under favorable jet support then deeper weekend
cyclo/frontogensis.

An amplified upper trough will support terrain enhanced heavy
snows over the Southwest and s-central Rockies states Fri. The
trough lifts northeastward over the central and eastern U.S. this
weekend overtop an amplified and slow to erode Bahamas/Southeast
upper ridge. A threat for heavy snow/ice lifts with a deepening
surface low from the Plains to the Upper Midwest/Great
Lakes/Northeast. New trough energies dig into a still unsettled
West this weekend/early next week, albeit with less gusto than the
lead systems.


...Guidance/Predictability Assessment and Preferences...

Models and ensembles solutions cluster quite well at mid-larger
scales and a favored composite of the GFS/ECMWF, GEFS/ECMWF
ensemble means and the National Blend of Models maintain excellent
WPC continuity in a pattern with above normal predictability.

Schichtel


WPC medium range 500mb heights, surface systems, weather grids,
quantitative precipitation and winter weather outlook
probabilities are found at:

<a href="https://www.wpc.ncep.noaa.gov/medr/5dayfcst500_wbg.gif"><u>https://www.wpc.ncep.noaa.gov/medr/5dayfcst500_wbg.gif</u></a>
<a href="https://www.wpc.ncep.noaa.gov/medr/5dayfcst_wbg_conus.gif"><u>https://www.wpc.ncep.noaa.gov/medr/5dayfcst_wbg_conus.gif</u></a>
<a href="https://www.wpc.ncep.noaa.gov/5km_grids/5km_gridsbody.html"><u>https://www.wpc.ncep.noaa.gov/5km_grids/5km_gridsbody.html</u></a>
<a href="https://www.wpc.ncep.noaa.gov/qpf/day4-7.shtml"><u>https://www.wpc.ncep.noaa.gov/qpf/day4-7.shtml</u></a>
<a href="https://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4"><u>https://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4</u></a>