598
FXUS02 KWBC 041825
PMDEPD

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
225 PM EDT Fri Jul 4 2025

Valid 12Z Mon Jul 07 2025 - 12Z Fri Jul 11 2025

...Hazardous heat and humidity over parts of the East; building
over the West...


...Pattern Overview...

Quasi-zonal flow over most of the CONUS to start the week will
transition toward an upper high starting to take residence near Las
Vegas and increased troughing into the Northeast. This will favor
a fairly typical summertime pattern but without much, if any,
monsoon signal into the Southwest.

...Guidance/Predictability Assessment

Overall, the latest 00Z/06Z/suite of guidance maintained good
agreement through the period, but the GFS/GEFS were notably on the
faster side from the Northeast Pacific into western North America
from around Tuesday onward. Preferred the larger consensus around
the 00Z ECMWF/Canadian/UKMET and ECMWF-AIFS. For the sensible
weather grids, the NBM was a reasonable starting point.

...Weather/Hazards Highlights...

At this point, there does not appear to be a focused heavy
rainfall threat for Mon/Tue and the Excessive Rainfall Outlook
areas remain at the Marginal (level 1 out of 4) category. Heavier
rainfall will be tied to the progressive cold fronts and the
stationary boundaries as well as around the upper high in the
southern Rockies. For the end of next week, the wavy front into the
east may be a focus for heavier rain and thunderstorms as it
typical for mid- summer. This includes areas from the Corn Belt
into the Midwest and OH Valley, Appalachians, Mid-Atlantic, and
Northeast.

Initially higher heights in the east will favor into the
Northeast/Mid-Atlantic but that will shift southward into the
Southeast after Monday then trend smaller by the end of the week
due to increased troughing. Consequently, the heat looks to build
into much of the West as the upper high strengthens over the
Southwest. This will push temperatures well over 100F in the lower
elevations and prohibit much rainfall except for perhaps far
southeastern AZ into NM early in the week. Experimental HeatRisk
values may rise to Major or Extreme levels (3 out of 4 or 4 out of
4) from the CA Deserts into southern NV, UT, and AZ.


Fracasso


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


$$