710
FXUS66 KMFR 231539
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
839 AM PDT Sat Aug 23 2025

.DISCUSSION...Satellite image shows varying amounts of mid level
clouds as monsoonal moisture continues to move north into the
area. The formation ofthe clouds indicates instability is already
present and as we get further in the day with daytime heating.
Instability will only increase more. A weak trigger is expected to
move into southeast Lake and Modoc County and CAPE values in
these areas are also high. This type of pattern is little
concerning and one where we should have at least a isolated
thunderstorms later this afternoon and evening in these areas.
Thus, they have been added to the forecast. Isolated storms will
end this evening, but still could not rule out isolated
convective showers in southeast Modoc County as we`ll remain
marginally unstable as with most southeast flow and a continued
influx of monsoonal moisture.

Some data suggest the potential for isolated storms as early as
Sunday morning, and it`s becoming more likely we`ll have increased
thunderstorms late Sunday morning through Sunday afternoon.
There`s some evidence suggesting storms that do fire up over the
Siskiyous will move north, and/or even develop in portions of the
westside, including the Rogue Valley and possibly towards Grants
Pass. We`ll look at this in more detail.


&&

.AVIATION...23/12Z TAFs...IFR/LIFR conditions have spread northward
through Coos County and could grow inland into coastal valleys.
Elsewhere, VFR will continue through the TAF period.

The only concern today will be isolated thunderstorms in southeast
Lake and Modoc County after 21-22z until around 3z. -Petrucelli


&&

.MARINE...Updated 800 AM PDT Saturday, August 23, 2025...Conditions
will continue to gradually improve today. North winds will persist,
but the strongest winds are expected over the outer waters where
near advisory winds could result in periods of steep seas, generally
beyond 30 nm from shore, through the weekend. Periods of gusty north
winds could return early to mid next week, along with steep seas,
then winds weaken for the latter half of next week. -BPN/BR-y


&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Extreme Heat Warning until 8 PM PDT Monday for ORZ024-026.

     Heat Advisory until 8 PM PDT this evening for ORZ023-025-
     027>031.

CA...Extreme Heat Warning until 8 PM PDT Monday for CAZ080-081.

     Heat Advisory until 8 PM PDT this evening for CAZ082>085.

PACIFIC COASTAL WATERS...None.

&&

$$