Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
751 PM EDT Wed May 29 2019
Valid 12Z Sat Jun 01 2019 - 12Z Wed Jun 05 2019
...Overview/Weather Highlights and Guidance
Evaluation/Preferences...
Active flow with a North Pacific upper-level jet splits as it
approaches the West Coast of North America. An upper-level low
will persist this period near California in the southern stream,
with a hot downstream upper ridge repositioning over the
south-central U.S. as heights falls support more refreshing flow
over the Southeast/East.
Meanwhile, a western Canadian upper ridge shifts to central Canada
and north-central U.S. by early next week. Farther east, northern
stream energy will periodically encounter a persistent upper low
over eastern Canada. These shortwaves will amplify as they dig
into the Great Lakes and Northeast, traversing the broad cyclonic
flow.
Underneath, slower progressing southern stream energies will
periodically eject from the California upper low, reaching the
central U.S. and potentially interacting with amplifying northern
stream energy. This combined with return flow into a slow moving
barocliinc zone may prove significant next week in support of
periods with strong to severe mcs/convection and locally heavy
rainfall with a flood/flash flooding threat. A main threat area
may focus from the south-central Plains to the mid-MS Valley.
The WPC medium range product suite was mainly derived from
seemingly reasonable and compatable 06 UTC GEFS and 00 UTC ECMWF
ensemble guidance composite. Limited input from deterministic
models was used given smaller scale convection/surface reflection
detail variance. This maintains good WPC continuity as consistent
with uncertainty.
Schichtel
Hazards:
- Heavy rain across portions of the Central and Southern Plains,
the Middle and Lower Mississippi Valley, the Great Lakes and the
Ohio Valley, Mon-Wed, Jun 3-Jun 5.
- Flooding possible across portions of the Northern, Central and
Southern Plains, the Northern Rockies, the entire Mississippi
Valley and the Great Lakes.
- Flooding occurring or imminent across portions of the Northern,
Central and Southern Plains, the entire Mississippi Valley, the
Great Lakes and the Ohio Valley.
- Flooding likely across portions of the Northern and Central
Plains, the Upper and Middle Mississippi Valley and the Northern
Great Basin.
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