296
FXUS02 KWNH 060614
PREEPD

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
213 AM EDT Fri Jun 6 2025

Valid 12Z Mon Jun 09 2025 - 12Z Fri Jun 13 2025


...Heavy rain threat for the South into next week...

...Interior West to South Texas heatwave into early next week...


...Overview...

An initial upper low over the Upper Great Lakes on Monday will
open up as it slides into and out of the Northeast on Wednesday.
This will push a cold front through the Eastern U.S. as the western
portion of this front settles across the South for several days.
Moisture and instability along this front will support rounds of
moderate to heavy rainfall particularly from the Southern Plains
into the Gulf Coast states. Upper ridging over the West and
southern Texas will result excessive heat threats before short
range energy moves into both regions. Deeper troughing will move
into the West later next week.


...Guidance/Predictability Assessment...

Model and ensemble guidance shows above average agreement on
overall large scale pattern and evolution next week, but with
plenty of uncertainty in the details. Good agreement on timing of
the trough through the East early week, but the GFS is a bit
stronger with the energy as it moves through the Northeast.
Otherwise, more noticeable differences begin to arise next Thursday
with the next trough into the West. The ECMWF is faster with an
initial but weak shortwave through the Northwest and the GFS is
stronger with energy dropping out of the base of an upper low over
far Western Canada that moves into the Northwest next Friday. The
ensemble means seem to be a more reasonable starting point for the
latter half of the forecast.

The WPC forecast for tonight used a blend of the deterministic
models through Day 5, with very good agreement. After this,
increased weighting of the ensemble means to help mitigate the
bigger differences that arise with Western U.S. troughing.


...Weather/Hazards Highlights...

A trailing frontal boundary draped across the South will provide
focus for numerous showers and thunderstorms through much of next
week. Moderate to locally heavy rainfall is possible and the Days 4
and 5 Excessive Rainfall Outlooks (valid Monday and Tuesday)
highlight this threat with broad marginal risks stretching from the
southern High Plains, across Texas and the lower Mississippi
Valley, and into parts of the Southeast. There remains enough
disagreement in exact placement of heavy rainfall to preclude a
slight risk, but it is possible one will be needed somewhere as
models come more in line, especially for areas that have seen
recent heavy rainfall. The northern portion of this boundary will
be quicker to move through the East, but there could be a heavy
rainfall threat over parts of interior New England and so a
marginal risk area was added to the Day 5/Tuesday ERO tonight.
Elsewhere, precipitation will increase across the Northern Rockies
and into the Northern Plains ahead of a frontal system the second
half of the week.

Much above normal temperatures will continue from the weekend into
early next week for the Northwest, with anomalies of +20-25F
likely. This should equate to a moderate to major heat risk for
parts of this region along with widespread record highs through at
least Monday. Temperatures and heat risk should moderate Tuesday
and Wednesday, but remain slightly above normal. Major to locally
extreme heat risk will continue across South Texas as well into
Monday, becoming much less extreme by Tuesday as an upper level
shortwave moves into the region. By next Thursday and Friday, most
of the country will be near or within a few degrees of normal.


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









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