Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
412 PM EDT Mon Jun 17 2019
Valid 12Z Thu Jun 20 2019 - 12Z Mon Jun 24 2019
...Weather Highlights/Threats...
A dynamic southeast Canada/Northeast U.S. upper trough will tap
moisture and instability to support a risk of locally heavy
convective rains across the Northeast through later this week as a
series of inland frontal waves try to consolidate and deepen
offshore. The trough is expected to slowly give way to a warming
upper ridge building from the east-central U.S./Southeast up into
the Great Lakes by early next week. This ridge builds ahead of a
series of upstream closed troughs that drift/reform from the
Northwest to the Rockies and northern Plains/south-central Canada.
These systems will present an emerging threat of locally heavy to
severe convection and heavy rainfall with surface frontogenesis
and cyclogenesis and moisture/instability return. Height falls
also dig through an unsettled and moderated West and lead to an
emerging convective rainfall potential pattern over the
south-central U.S.
...Guidance/Predictability Assessment...
The WPC medium range product suite was primarily derived from a
composite blend of compatable guidance from the 06 UTC GFS and 00
UTC ECMWF guidance Day 3/4 (Thu/Fri).
While the overall mass field pattern evolution is fairly well
defined by most guidance, opted to transition to a more compatable
06 UTC GEFS and 00 UTC ECMWF ensemble blend by days 6/7 in a
period of decreasing forcast predictability and model run to run
continuity, especially with the focus for more localized
summertime weather and hazards.
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
Hazards:
- Heavy rain across portions of the Central/Southern Plains, to
the Ohio Valley, Sat-Sun, Jun 22-Jun 23.
- Heavy rain across portions of the Northern/Central Plains, and
the Upper Mississippi Valley, Fri, Jun 21.
- Heavy rain across portions of the Northeast, Thu-Fri, Jun 20-Jun
21.
- Severe weather across portions of the Central Plains, the
Middle/Upper Mississippi Valley, Fri, Jun 21.
- Flooding possible across portions of the Central/Southern
Plains, and the Ohio Valley.
- Flooding occurring or imminent across portions of the
Missouri/Mississippi River Basins.
- Flooding likely across portions of the Southern Plains and the
Central Great Basin.
- Excessive heat across portions of the Southern Plains, Thu-Mon,
Jun 20-Jun 24.
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