Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
316 AM EDT Fri Mar 22 2019
Valid 12Z Mon Mar 25 2019 - 12Z Fri Mar 29 2019
...Guidance Assessment/Preferences...
Latest models and ensembles seem compatable Mon/Tue and prefer a
composite solution to smooth the less predictable smaller scale
features. While guidance overall offers a fairly similar larger
scale pattern evolution for the next week, run-run variance with a
multitude of smaller embedded systems and stream interactions
grows quickly. Accordingly, it seemed more prudent to favor an
ensemble mean forecast approach days 5-7 and the WPC medium range
product suite was primarily derived from a blend of latest
GEFS/ECMWF ensembles.
...Weather Highlights and Hazards...
This medium range period starts Monday/Tuesday as a southern
stream front with several moisture/enhanced precipitation focusing
waves ejects across the South/Southeast/and Mid-Atlantic. These
waves cut underneath/interact with a cooling northern stream
frontal drape whose post-frontal high pressure builds down through
the central and eastern U.S.
Meanwhile, a protracted series of Pacific systems with associated
height falls and enhanced precipitation swaths will track onshore
and across much of the West early through mid next week in advance
of an mean closed low/trough reinforced just off West Coast.
Expect heaviest precipitation/heavy mountain snows threats from
northern California/Oregon to the northern Rockies. Indication
that the bulk of Pacific trough energy will eject through the West
Wed/Thu to emerge over the Plains later next week to induce
cyclo/frontogenesis. This may occur just as a renewed northern
stream may force cool air down into the unsettled n-central
states. This airmass would prove to be in stark contrast to a
rapidly warming airmass spreading over the e-central U.S. where
moist Gulf return flow may fuel an expanding risk of enhancing
rains/convection channeling between the surging fronts and
retreating eastern U.S. high pressure.
Schichtel
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