772
FXUS02 KWBC 071858
PMDEPD

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
258 PM EDT Sat Jun 7 2025

Valid 12Z Tue Jun 10 2025 - 12Z Sat Jun 14 2025


...Heavy rain threat for the south-central U.S. next week...

...Hot temperatures in the Interior West Tuesday gradually moderate
mid to late week...


...Overview...

A cold front will swing through the Northeast early next week,
providing support for locally heavy rain and thunderstorms on
Tuesday. The western portion of this front will settle across the
South before eventually lifting northward as a warm front. Moisture
and instability along this front will support rounds of moderate
to heavy rainfall that could cause flash flooding across the south-
central U.S. through much of next week. To the north, a shortwave
moving through the Northwest through the northern Plains will
bring showers and thunderstorms mid to late next week. Upper
ridging ahead of this shortwave should produce one more day of
potentially hazardous heat in the West Tuesday, and then
temperatures should gradually moderate due to the shortwave and
then deeper troughing reaching the West Coast later week.


...Guidance/Predictability Assessment...

Dynamical, AI, and ensemble model guidance all continue to show
above average agreement on the overall large scale pattern and
evolution during the medium range period, but still with plenty of
uncertainty in the details which would impact sensible weather. For
example, models are quite agreeable with a northern stream upper
trough lifting from the Great Lakes Tuesday to Northeast Wednesday
and a northern stream upper trough behind, but more variable with
the smaller scale southern stream troughing/energy moving through
Texas and vicinity, which causes some rainfall placement and amount
differences. Farther west, shortwaves tracking across the
Northwest to northern Plains show similar minor spread. By late
week, troughing will get well established over the eastern Pacific
and sneaking into the West Coast. An embedded upper low has some
spread in its position, with the EC and CMC farther northeast in
western Canada and GFS runs farther southwest, with the ensemble
means generally in between. The newer 12Z models have converged
somewhat with this. Meanwhile a subtropical ridge will build across
the U.S. southern tier into next weekend, with good model
consensus.

Given the good model agreement early in the period, maintained a
multi-model deterministic blend of the 00/06Z models for the
updated forecast. Added in some ensemble mean component to the
blend by Day 5 and increased the proportion of ensemble means to
half by Day 7, given the increasing spread particularly with the
western trough details.


...Weather/Hazards Highlights...

A trailing frontal boundary draped generally west to east across
the South will provide focus for numerous showers and thunderstorms
through much of next week. The Days 4 and 5 Excessive Rainfall
Outlooks (valid Tuesday and Wednesday) reflect this. For Day 4, a
Marginal Risk stretches from the southern Rockies and Plains into
the central Gulf Coast states along and ahead of the front. Model
guidance has converged better on an excessive rainfall threat
centered over west-central Texas on Tuesday, with potential for
convection to remain Tuesday morning before a nocturnal round of
storms with heavy rain rates Tuesday night. Thus will upgrade to a
Slight Risk in this area where ample moisture and instability
interacts with the front and a shortwave aloft. By Day 5/Wednesday,
continue to carry a Slight Risk in parts of Texas, expanded
somewhat from the previous issuance to cover possible multiple
convective complexes and also the increasing spread in position of
heaviest rain. By Thursday-Friday, the frontal boundary should
gradually lift northward, with heavy rainfall moving into Oklahoma
and the Lower/Middle Mississippi Valley. Much of this area has been
wet as of late and will need to be monitored for flooding concerns
later this week.

The northern portion of this front should be quicker to move
through the East, but heavy rainfall is possible along the boundary
amidst ample moisture and instability and favorable upper level
dynamics. A Marginal Risk for the interior Northeast remains on the
Day 4 ERO. Elsewhere, additional shortwave energy interacting with
a frontal boundary across the northern tier will bring showers and
storms across parts of the northern Rockies into the Upper
Midwest. Moisture anomalies should be above the 90th percentile in
Montana, prompting a Marginal Risk there for the Day 5/Wednesday
ERO. Additionally, convection is likely to move through the north-
central U.S. along the cusp of the instability gradient. Will
maintain a Marginal Risk there as well for Wednesday, with some
broadening but a general southward adjustment from the previous
shift per model trends. Additional rounds of rain and storms are
possible in the northern tier through late next week.

Much above normal temperatures will continue into Tuesday for the
Northwest, with anomalies of +20-25F likely for one more day. A few
record highs are possible there along with moderate HeatRisk, and
moderate to major HeatRisk is forecast to expand south through the
Great Basin and Desert Southwest. Western heat should gradually
moderate as the week progresses, but could remain above normal
especially over the Great Basin. Most other areas look to be within
a few degrees of average by later next week, though the Mid-
Atlantic could see temperatures of 5-10F above average Thursday-
Friday with highs reaching the 90s. Average temperatures are
reaching the 90s in the southern tier this time of year though,
and the subtropical ridge will produce hot and humid conditions and
warm overnight lows.


Tate/Santorelli


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


$$