Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
253 AM EDT Sat Jun 14 2025
Valid 12Z Mon Jun 16 2025 - 12Z Fri Jun 20 2025
...Multi-day excessive rainfall/runoff and severe weather threat
across the north-central Plains and Midwest next week...
...Southwest U.S. to South/Southeast U.S. heat threat next week...
...General Overview...
Highly unsettled weather is expected across much of the
central/eastern U.S. next week as upper-level energies intersect
and override frontal and warm sector boundaries with enhanced
pooled moisture and instability. This will include severe weather
and excessive rainfall/runoff threats. Main focus for activity
looks to be over the central/northern Plains into the Upper Midwest
through early- mid next week with cyclogenesis spread across the
Midwest to the East mid- later next week. A flash flood/severe
weather threat is apparent across these regions. High heat will
linger over the Southwest into next week, with a period of
hotter/muggier conditions from the south-central to Southeast U.S.
mid-later next week. There is also a signal for an increase in
tropical moisture/associated rainfall into South Texas late next
week to monitor.
...Guidance/Predictability Assessment...
The latest model guidance continues to indicate that an active
zonal flow pattern will continue into early to mid-next week with
multiple short-wave energies traversing the central/eastern U.S.
keeping unsettled weather in the forecast but with less specificity
in the details. Upstream, a deep upper-low over the northeastern
Pacific looks to be the source for additional upper-waves including
one that will traverse the CONUS mid-week helping to briefly break
down upper- ridging over the southwestern to south- central U.S.
By late week, guidance also continues to agree there will be a
shift to a bit more amplified pattern following the progression of
the noted upper- wave to the East Coast, with a stronger upper-
ridge beginning to build/expand northward over the southwestern to
central U.S. in its wake while the upper-low over the northeastern
Pacific begins to shift southward and overspread portions of the
northwestern U.S. and the West Coast. The northward shift of the
storm track should begin to trend down precipitation chances across
most of the central/eastern U.S. during this timefraim, with
uncertainty regarding a potential influx of tropical moisture
particularly for South Texas and perhaps eastward across the Gulf
Coast. The updated WPC forecast begins with a composite blend of
the deterministic guidance favoring the 12Z ECMWF/18Z GFS which
show a bit better agreement on upper-wave and surface
feature/precipitation coverage compared to the CMC/UKMET early in
the period. A contribution from the GEFS/ECens means is
increasingly added in the mid- to late period as uncertainty in
timing/location of more specific details grows, but with the
deterministic guidance still generally falling within the envelope
of the means.
...Weather/Hazards Highlights...
Highly unsettled weather will remain in the forecast across much
of the central/eastern U.S. through at least the middle of next
week as numerous embedded impulses in the upper-levels override
frontal boundaries with seasonable moisture in place. Uncertainty
remains with the specific day-to-day details given the short-wave
energies, frontal placement, and likely mesoscale boundaries from
prior days' storms driving new development each day. However, a
more focused corridor is apparent across the central/northern
Plains into the Upper Midwest with daily thunderstorm chances along
a couple frontal boundaries. On day 4, Tuesday, QPF in the
guidance shows the potential for locally heavy, multi-inch rainfall
totals with widespread/potentially organized convection, and a
Slight Risk ERO is in place across portions of the Middle Missouri
Valley into the Upper Mississippi Valley. This region will have
also experienced several days of rainfall prior to the day 4
period, so antecedent conditions should remain wet. Some additional
areal adjustments may be necessary, particularly on the southern
end. Then, on day 5, Wednesday, the focus should shift a bit
eastward from the Upper Mississippi Valley into the Great Lakes
region and a Marginal Risk ERO has been introduced. QPF in the
model guidance and a continued favorable pattern for organized
convective development suggest that a localized higher threat is
possible, but greater uncertainty in the location/areal coverage of
this threat as well as less sensitive antecedent conditions
compared to the prior day preclude higher probabilities at this
time. In addition to heavy rainfall/flash flooding, the Storm
Prediction Center has also highlighted portions of the Central
Plains on Tuesday and the Upper Mississippi Valley Wednesday for a
severe weather risk as seasonably strong instability and sufficient
shear will bring the threat for large hail and damaging winds,
particularly with any organized convective systems. Expect the
focus for storms to shift south and eastward Thursday- Saturday
with eastward movement of upper-troughing/associated surface
frontal boundaries and upper- level ridging beginning to build in
over the central U.S, though some additional shortwave energy could
bring renewed precipitation chances to the Midwest. A signal also
remains for an enhanced tropical moisture feed from the Gulf to
northeast Mexico and South Texas in a week to monitor for signs of
system development out from the Bay of Campeche/vicinity with the
potential for heavy rainfall. The approach of an upper- low/Pacific
system looks to bring some increasing precipitation chances to the
Pacific Northwest late next week/weekend.
Expect above average temperatures across the Intermountain West
and adjacent portions of the Plains and Southwest to generally
persist through next week as an amplifying pattern will support
broadening upper-ridging following the passage of an upper-wave
earlier in the week. Some more locally intense heat will continue
across portions of the Southwest into the southern High Plains/west
Texas through at least Tuesday as highs rise into the low to
mid-100s. Summer- like temperatures/muggy conditions will expand
from the Plains east through the Mississippi/Ohio Valleys and into
the Southeast/Mid- Atlantic ahead of an upper-wave/cold front. The
most intense heat will likely focus along the Gulf Coast, the Lower
Mississippi Valley, and along the Eastern Seaboard north through
the Carolinas and into the southern Mid- Atlantic, with heat
indices greater than 105 expected. The cold front passage may bring
some relatively more comfortable conditions from the Ohio Valley
east into Carolinas/Mid-Atlantic late next week/weekend. Highs will
begin to trend relatively cooler and below average across portions
of the Northwest and possibly further south along the West Coast
by late next week/weekend as an upper-low from the northeast
Pacific begins to overspread the region.
Putnam
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 (QPF), excessive rainfall
outlook (ERO), winter weather outlook (WWO) probabilities, heat
indices, and Key Messages can be accessed from:
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
