383
FXUS02 KWNH 050700
PREEPD

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
259 AM EDT Thu Jun 5 2025

Valid 12Z Sun Jun 08 2025 - 12Z Thu Jun 12 2025


...Severe weather possible in the southern through the weekend,
with heavy rain possible there through much of next week...

...Heat wave for the Interior West with some heat in South
Texas...


...Overview...

Multiple rounds of thunderstorms that may be severe and/or cause
flash flooding in the southern tier in particular as expected to
accompany fronts pushing through the Plains eastward. Meanwhile,
rounds of ridging over the West (though interrupted by shortwaves)
will lead to much above normal temperatures.


...Guidance/Predictability Assessment...

The latest suite of guidance continued to show agreement of the
large scale features yet wavered on details. Consolidated energy
diving across south-central Canada will form an upper low by Sunday
that reaches the Upper Midwest/Great Lakes on Monday and deepens
the trough slightly across the east- central U.S. The timing and
strength of shortwave energy and associated surface fronts remain
uncertain.

Within general spread, the GFS continues to depict a relatively
deep surface low atop Ohio/Pennsylvania by early Sunday and higher
QPF than the rest of the cluster. Consensus persists for this
trough axis to start moving more quickly east by midweek.
The northern stream upper ridging to be atop the Northwest over
the weekend, expanding and moving east across the Intermountain
West gradually next week as a trough may reach the West Coast by
Tuesday or Wednesday. A southern stream low offshore California to
start the period on Saturday looks to shrink/weaken but perhaps
drift inland early next week, with more uncertainty.

The preferred WPC blend utilized 18Z GFS and 12Z ECMWF/CMC/UKMET
as a starting point and then included modest weighting of the EC
ensemble and GEFS mean beyond the weekend


...Weather/Hazards Highlights...

Showers and thunderstorms may continue to linger across the
Northeast while the front pulls further offshore Sunday. However
convection will continue along front that stretches through the
Lower Ohio/Tennessee Valleys, Lower Mississippi Valley, and into
the Southern Plains. Greater rainfall rates and accumulations are
likely to focus over portions of Oklahoma and Texas where there
will be pooled Gulf moisture and high instability to tap into and
recent heavy rains. The Storm Prediction Center continues to show
the potential for severe weather across the South/Central Plains
east into the Southeast. WPC maintained the broad Marginal Risk
from the Texas Panhandle to the Southeast Coast with an embedded
Slight along the Red River into the Ark-La-Tex. The front will
advance southward by Monday and the precipitation will be
widespread across the Gulf states, Lower Mississippi Valley, and
eastern parts of the Southern Plains. WPC raised a broad Marginal
Risk that stretches from eastern New Mexico to western Georgia.
Given the variances on the location of the highest QPF opted to
keep the threat potential as a level 1 although there are signal
for local 2 to 4 inches which may require a future upgrade to a
Slight should agreement improve.

Meanwhile, another frontal system will track across the
Midwest/Great Lakes for some modest rain there over the weekend,
reaching the Northeast by Monday and Tuesday. The current forecast
continues to show the leading front dissipating while this
secondary front becomes dominant. The second front settling south
will once again promote rain and thunderstorms across the southern
Plains and Southeast through the first half of next week as the
moisture and instability lingers.

Temperatures are expected to be near to slightly below seasonal
average for central and eastern portions of the country with the
troughing. For southern Texas daily readings will climb well into
the 100s with heat indices possibly above 110F. But the largest
temperature anomalies will be across the Northwest U.S. through the
weekend into early next week underneath mean upper ridging. This
region will observe readings 15 to 25 degrees warmer than average
for early June, with some interior locations hitting the 90s. Even
cities like Seattle look to reach the mid to upper 80s. Above
normal temperatures will stretch into the central Great Basin, and
the Desert Southwest can expect temperatures well into the 100s to
110 degrees. For safety information, see weather.gov/heat.


Campbell/Tate


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





$$