Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
308 AM EDT Mon Jun 30 2025

Valid 12Z Thu Jul 03 2025 - 12Z Mon Jul 07 2025


...Multi-day Heavy Rain/Flash flooding threat for Florida...

...Southwest U.S. to southern Rockies/High Plains monsoonal rains
as the tropics activate over the eastern Pacific and the Gulf...

...Northern Plains/Upper Midwest Heavy Convection/Rain threat...


...Guidance/Predictability Assessment...

Guidance through the first half of the medium range period for
Thursday into Saturday remains in relatively good agreement. For
the second half of the period, the most pronounced differences
remain with the handling of northern and southern stream energy
differences from the Pacific to the West Coast and inland. This
affects how much a warming Central U.S. ridge gets eroded to the
north and with smaller scale mesoscale systems riding the top of
the ridge. One thing that has been consistent is the guidance
continuing to show an increased signal for monsoonal flow into the
Southwest Thursday into Friday with some connection to Tropical
Storm Flossie in the East Pacific off Mexico and T.D. Barry out
from the Gulf. Some guidance is also hinting at leftover Gulf low
pressure from a weakening frontal boundary out from the Southeast
U.S. may impact the Florida Peninsula by later this week. This
system is being monitored with low probabilities of developing
tropical characteristics by the National Hurricane Center.

Accordingly, the WPC forecast used a model blend the first half of
the period Thursday/Friday before transitioning Saturday into a
GEFS/ECMWF ensemble solution later weekend into early next week
amid increasing forecast spread. This plan maintains good product
continuity with the previous WPC forecast and is overall in line
with a composite of machine learning and 00 UTC guidance.

...Weather/Hazards Highlights...

Thunderstorms with deep moisture/instability will bring heavy
convective downpours ahead of a upper trough and surface front into
late week for the far Southeast U.S./Florida where WPC Excessive
Rainfall Outlook (ERO) Marginal Risk areas exist Day 4/Thursday
and Day 5/Friday. A focus for multi-day heavy rains may work to
Gulf coastal central Florida where a Slight Risk area continues for
Day 4/Thursday and Day 5/Friday given precursor rains and heavy
rainfall potential given initial right entrance region upper jet
support and anomalous Gulf tropical moisture. Focus may shift
slowly southward over Florida over the weekend.

Monsoonal moisture with some connection to eastern Pacific (T.S.
Flossie) and Bay of Campeche (T.D. Barry) tropical features is
likely to increase coverage and potential of rain amounts into
later this week into the Southwest and southern Rockies/High
Plains on the western periphery of a warming central U.S. upper
ridge. A ERO Marginal Risk area is in place there for Day
4/Thursday, slowly shifting focus to the far southern High Plains
Day 5/Friday. Areas like the Sacramento Mountains, where the steep
terrain and burn scars cause the area to be particularly sensitive
to rain and most vulnerable to potential flash flooding, especially
with wet antecedent conditions there.

Elsewhere, periodic afternoon and nocturnal strong to severe
storms/MCS activity offer heavy rain/runoff potential to focus over
the north-central Plains and Upper Midwest late week into Saturday
as upper trough/impulse energies work over the northern periphery
of the main central U.S. upper ridge as moisture/instability pools
near wavy passing and draping fronts. WPC ERO Marginal Risk areas
have been introduced for Day 4/Thursday and Day 5/Friday. Weekend
to early next week activity with upper system/frontal progressions
then work over the central Midwest/Great Lakes and the Northeast.


Schichtel


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