Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
300 PM EDT Sun Jun 29 2025

Valid 12Z Wed Jul 02 2025 - 12Z Sun Jul 06 2025


...A wet period is expected for parts of north-central Florida...

...Southwest to southern Rockies/High Plains monsoonal flow as the
tropics activate over the eastern Pacific and Bay of Campeche...


...Guidance/Predictability Assessment...

Model guidance, at least through the first half of the medium
range period,
remains in relatively good agreement which features an upper low
exiting the Great Lakes and troughing being reinforced over the
West Coast. 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. The affects how much a Central U.S. ridge gets eroded to
the north, and 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 with some connection to Tropical Storm Flossie in the
East Pacific. Some of the guidance is also hinting at leftover low
pressure from a weakening frontal boundary over the Southeast,
which may move across the Florida Peninsula or linger in the
eastern Gulf. This system is being monitored for low probabilities
of developing tropical characteristics, as shown by the latest
Tropical Weather Outlook from the National Hurricane Center.

The WPC forecast for today used a general model blend the first
half of the period, increasing contributions from the ensemble
means the latter half for increasing spread. This does maintain
good continuity with the previous WPC forecast as well.


...Weather/Hazards Highlights...

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

Monsoonal moisture with some connection to eastern Pacific (TS
Flossie) and Bay of Campeche (TS Barry) tropical features is
likely to increase coverage and potential of rain amounts into mid-
later this week into the Southwest and southern Rockies/High
Plains on the western periphery of a warming central U.S. upper
ridge. ERO Marginal Risk areas are in place there for Day
4/Wednesday and Day 5/Thursday. 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
offer a varied guidance signal to monitor for heavy rain/runoff
potential to emerge more clearly out from the northern Rockies to
focus locally over the northern Plains and Upper Midwest midweek
into next weekend as upper trough/impulse energies work on
moisture/instability pooling near wavy passing and draping fronts.
Weekend activity with upper system/frontal progressions is slated
to work into the central Plains and across the Midwest/Great Lakes.


Santorelli/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