Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
1100 AM EST Thu Mar 07 2019
Valid 12Z Sun Mar 10 2019 - 12Z Thu Mar 14 2019
...Weather Pattern Overview...
The stormy weather pattern continues as two major systems thrive
during the medium range period. A lead Great Lakes storm Sund will
bring widespread rain/thunderstorms to the eastern U.S. and heavy
snow with a threat of blizzard conditions to the Upper Midwest and
Great Lakes before exiting into eastern Canada Mon. A second
potent system works from the Pacific inland to CA and the
Southwest Mon/Tue, with central U.S. storm genesis likely through
midweek.
...Guidance and Uncertainty Assessment...
The deterministic models are in good overall agreement regarding
the placement and overall strength of the surface low crossing the
Great Lakes region on Sunday and into eastern Canada by Monday.
Speed differences are much more apparent with the GFS/GEFS mean
and to a lesser extent the FV3 remaining more progressive with the
midweek storm system across the central U.S. than the
ECMWF/UKMET/CMC and ECMWF ensemble mean. The increasingly short
wavelength spacing with upstream kicker energy digging through the
West now seems sufficient to trend the latest WPC product suite to
a solution faster than WPC continuity. The bottom line is that
even though timing has been an issue with this storm threat, there
has been a consistent and strong signal for significant storm
development that should not be downplayed in a pattern ripe with
deep/dynamic low developments.
...Weather Highlights and Hazards...
Heavy snow is still expected across interior portions of New
England as the surface low lifts northeastward across eastern
Canada Sun into Mon, and heavy lake enhanced snow will persist on
the windy backside flow around the exiting deep low. Areas of rain
and thunderstorm activity will persist across the Gulf Coast
region and over the East Sunday underneath along/ahead of a
trailing cold front. Some severe thunderstorms will also be
possible across parts of the Southeast on Sunday ahead of the cold
front, and this is something that the Storm Prediction Center is
continuing to monitor.
Looking ahead for early-mid week, the pattern again favors an
amplified mid-upper level trough developing off the West Coast
this weekend. This will support another round of precipitation
over the southwestern U.S. as the trough moves inland on Monday.
Additional widespread rain is expected to develop across the
central and southern Plains to the Mississippi Valley/Midwest
during the Tuesday and Wednesday time period as the trough induces
another deepening surface low east of the Rockies. There is also
the potential for severe weather with this storm system, and
details on this will become more evident in the upcoming days.
Another round of heavy snow and potential blizzard conditions is
becoming more probable across parts of the central plains and the
Upper Midwest as the surface low intensifies and colder air in
drawn in behind the low.
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