595
FXUS02 KWBC 020808
PMDEPD

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
408 AM EDT Tue Jun 2 2026

Valid 12Z Fri Jun 05 2026 - 12Z Tue Jun 09 2026


...Overview...

Mid-level vortices emerging out of Mexico will promote scattered
shower and thunderstorm activity over the Great Plains and
Mississippi Valley. Transient shortwave energy propagating through
the Northern Plains/Upper Midwest and southern Canada will also
generate showers and storms from the Upper Midwest to the Northeast
this weekend. Downstream from the aforementioned troughs, a ridge
will promote warm temperatures for much of the Eastern U.S..
A deep upper-level trough will bring some rainfall to the Northwest
this weekend, before another trough arrives with another round of
precip on Monday.


...Guidance/Predictability Assessment...

A general model blend comprised of the available deterministic and
Ai guidance were used in the blend on days 3 and 4, due to their
agreement on the overall synoptic pattern evolution across the
lower 48. Models begin to stratify on day 5, when the trough timing
and intensity over the Northeast become uncertain. Ensemble means
are introduced to mitigate some of these deterministic differences,
especially by days 6 and 7 when the deterministic models are highly
variable regarding the amplitude and timing of an approaching
Pacific trough.


...Weather/Hazards Highlights...

A slow moving frontal boundary sliding southward through the
northern tier of the country will bring scattered to isolated
showers and thunderstorms to portions of the Upper Midwest, Great
Lakes, Northeast, and eventually Ohio Valley/Mid-Atlantic.
Convection on Friday could produce isolated instances of flash
flooding over portions of the Middle to Upper Mississippi Valley,
which is supported by the presence of a marginal risk (at least 5%
chance) of excessive rainfall. Showers and thunderstorms shift into
the Ohio Valley and Great Lakes on Saturday before finally
spreading into the interior Northeast and Mid-Atlantic by Sunday
and Monday, where there`s potential for heavy rainfall to occur.

Mid-level shortwaves gliding northward out of Mexico will be
responsible for multiple rounds of diurnal convection spreading
from the Southern Plains this Wednesday and into the Lower
Mississippi Valley by early next week. A more amplified trough will
generate rainfall across the Pacific Northwest on Friday/Saturday
then spreading into the Northern Plains and Upper Midwest on Sunday
and Monday. Another System arrives over the Pacific Northwest on
Monday, bringing renewed chances for rain.

Broad moist southerly flow into the Plains and Eastern U.S. will
promote above average temperatures for those areas this weekend.
Overnight low temperatures struggling to make it below 70 degrees
will raise heat risk concerns over portions of the Mid-Atlantic and
Northeast Coasts this weekend.


Kebede


Additional 3-7 Day Hazard information can be found on the WPC
medium range hazards outlook chart at:
https://www.wpc.ncep.noaa.gov/threats/threats.php

WPC medium range 500mb heights, surface systems, weather grids,
quantitative precipitation forecast, excessive rainfall outlook,
winter weather outlook probabilities, heat indices and Key Messages
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/#page=ero
https://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4
https://www.wpc.ncep.noaa.gov/heat_index.shtml
https://www.wpc.ncep.noaa.gov/#page=ovw


















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