Grants Pass, Oregon 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

812
FXUS66 KMFR 140020
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
Issued by National Weather Service Portland OR
520 PM PDT Tue May 13 2025

.UPDATE...Updated Aviation Discussion.


.AVIATION...14/00Z TAFS....Areas of MVFR ceilings and isolated
showers will persist along the Oregon this evening, becoming
widespread tonight through Wednesday morning along the coast along
with local IFR. Inland, conditions are mainly VFR with local MVFR
and mountain obscurations. Areas of MVFR conditions will develop
west of the Cascades tonight and Wednesday morning, lifting to VFR
Wednesday afternoon.




&&

.PREV DISCUSSION... /Issued Issued by National Weather Service Portland OR/

DISCUSSION...Satellite image shows plenty of cumulus clouds over
the area along with isolated showers. This will continue into
early this evening. Once we lose daytime heating, isolated showers
will diminish early this evening with dry conditions most hours
and locations tonight. The exception will be along the Cascades
and eastern Lake County where a few showers are possible.

A weak disturbance will move into the area Wednesday morning and
could bring a few showers north of the Umpqua Divide and Coos
County. The afternoon should be dry once the disturbance moves
east.

Wednesday night will be dry, with weak upper ridging building into
the area. Cloud cover should be sufficient enough to keep
temperatures from dropping too much at night. Less cloud cover
east of the Cascades will result in colder overnight lows.

The upper ridge will flatten out some Thursday afternoon and
evening as another weak shortwave moves into the area. This will
result in a few showers mainly north of the Umpqus Divide and
Cascades, but also could not rule out a few showers in northern
Klamath and Lake County.

Weak ridging will build in later Thursday night into Friday with
dry and milder weather for the interior.

Another, but stronger upper trough will move in from the northwest
late Friday night into Saturday, with showers from late Saturday
morning through Saturday afternoon. Showers Saturday will tend to
be isolated in the morning, then increasing in coverage as the
upper trough moves overhead in combination with daytime heating.
Instability is marginal, and will be greatest east of the
Cascades, therefore could not rule out isolated afternoon and
early evening thunderstorms. Showers will continue Saturday night
as the upper trough remains overhead. Precipitation amounts will
generally be light Saturday through Saturday night. Snow levels
Saturday night are expected to be around 5000 feet and could
result in a brief accumulation of snow around Crater and Diamond
Lake, but with road temperatures warm due to stronger mid May
sun, snow for the most part should just melt.

Sunday will be a transition day as the upper trough departs with
upper ridging nosing into the area. Therefore any showers will be
isolated and confined to the morning hours along the northern
Cascades and north of the Umpqua Divide.

All signs are pointing towards dry weather for most of next week.
The operational ECMWF shows a stronger upper trough moving into
the area Thursday with cooler and unsettled weather. However, the
majority of the individual ECMWF ensembles members show a dry
solution and the operational GFS and their individual ensemble
members show a dry solution. Additionally, the majority of the
cluster solutions favor stronger upper ridging. -Petrucelli


MARINE...Updated 200 PM Wednesday, May 7, 2025...Steep seas along
with periods of rain will persist through Wednesday morning. A
pattern change will come on Wednesday with the return of a thermal
trough and associated gusty north winds and wind-driven seas
through Friday morning. -Spilde/Hermansen

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...CA...None.

PACIFIC COASTAL WATERS...Small Craft Advisory until 5 AM PDT
     Wednesday for PZZ350-356-370-376.

&&

$$

CC/CC/CC