Grants Pass, Oregon 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

438
FXUS66 KMFR 150426
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
826 PM PST Thu Nov 14 2024

.DISCUSSION...Here are a few 24-hour totals since 7:45 PM:
Medford: 0.54", Roseburg: 0.76", Coos County: Near 0.75"-1",
Western Siskiyou: 0.75"-1.25", and Lake County Airport: 0.32".

Radar currently shows a few more showers at the coast and in Jackson
County moving south. Lingering showers continue through tomorrow
afternoon, and less than an inch of new snow is expected in most
locations with around a tenth of an inch for new rainfall west of
the Cascades. Northerly winds will turn slightly breezy tomorrow
afternoon with gusts near 15-20 kt possible. The forecast is on
track, and the next area of concern is the Sunday system which is
discussed in the previous discussion. -Hermansen

&&

.MARINE...Updated 800 PM PST Thursday, November 14, 2024...

Showers and an isolated thunderstorm or two will continue through
tonight. Winds continue to shift, becoming northerly tonight into
Friday and swell dominated seas will remain elevated and hazardous
to small craft through Friday evening. Eventually, seas lower below
10 feet by Saturday morning. This improvement will be short lived,
however, with another front expected late Saturday through Sunday
with gusty south winds and steep to very steep seas. This will be
followed by another large swell late Sunday into Monday.

Lastly, while uncertainty is high due to a widespread variety of
model solutions, we are monitoring the potential for a strong storm
to develop over the eastern Pacific Ocean around mid-week. If far
enough east, this system has the potential (about a 15-30% chance at
this time) to bring high end gales to all the waters with storm
force gusts. Stay tuned as the time gets closer and details become
more clear. /BR-y

&&

.PREV DISCUSSION... /Issued 521 PM PST Thu Nov 14 2024/

Updated AVIATION Discussion...

AVIATION...15/00Z TAFS...Showers will continue through the evening
hours and into the overnight but gradually diminish after midnight.
Overall, expect a mix of VFR/MVFR ceilings/visibilities, lowest in
showers, but also areas of higher terrain obscured. Shower activity
won`t impact the terminals continuously, but mostly on and off
through about midnight. Though there should be a decrease in
coverage overnight into Friday morning as the trough moves inland,
some showers will continue focused near the Cascades, the Cascade
Foothills, the Siskiyous and over by the Warner Mtns.

If there`s enough breaks in the cloud cover later tonight, it could
result in IFR ceilings and visibilities for the interior westside
valleys late tonight into Friday morning. -Petrucelli/BR-y

PREV DISCUSSION... /Issued 233 PM PST Thu Nov 14 2024/

SHORT TERM...Thursday evening through Sunday morning...A lingering
upper trough will keep scattered showers in the forecast through
Friday evening across northern California and southern Oregon.
Southwest flow aloft will support shower chances west of and along
the Cascades today, while northerly flow on Friday could bring more
activity east of the Cascades. Slight chances for thunder (10-20%)
remain in the forecast for areas west of the Cascades through this
evening given upper level instability, but lightning flashes have
not been sensed so far today so thunderstorms seem unlikely. Snow
levels of are currently between 4000-5000 feet and will lower to
2500-3500 feet on Friday. Snow showers will be possible over the
Cascades, but with only 1 to 2 more inches expected in this area
through Friday afternoon. The upper flow on Friday could bring 2 to
6 inches of snow over the highest peaks in southern Lake County
while other areas will get an inch of snow or less. Overall, both
rain and snow showers look to be unimpactful through Friday night.

An upper ridge will start developing over the area early Saturday
morning, bringing a few dry hours on early Saturday morning. Later
in the morning to early Saturday afternoon, a warm front will bring
precipitation chances back to the area through early Sunday morning.
Warm air behind the front will lift snow levels to 6500 feet or
higher, so snowfall is not a concern for this part of the weekend.
Showers will start at the coast and move eastward through the day,
with the highest precipitation amounts over the Oregon coast and
eastern Douglas County up into the Cascades. These areas are
forecast to get between 0.75 and 1.0 inches of rain. The Umpqua and
Illinois valleys are expected to get about 0.4 to 0.5 inches, and
the Rogue Valley could get 0.2 inches or less. For areas east of the
Cascades, northern Klamath County could get between 0.25 and 0.33
inches, while other areas will get 0.1 inches or less.

This front will not be impactful as far as hazardous conditions.
Moderate to heavy showers will be possible, especially along the
coast and higher terrain. Strong winds and thunderstorms are not
expected. Taking a look at river forecasts shows a reasonable rise
given expected additional precipitation, but area rivers are not
near flood levels. A cold front follows the warm front on Sunday
afternoon, which will be discussed in the long-term forecast. -TAD

EXTENDED DISCUSSION...(Sunday through Thursday)...The cold front
will push into the area Sunday at which point we`ll have moderate to
occasional precipitation along and just ahead of the front, with
snow levels possibly lowering to the higher passes as colder air
aloft gets dragged down in areas of moderate to heavy precipitation.
The front will move from northwest to south late Sunday afternoon
and night, and we`ll see snow levels dropping down between 3000 and
3500 feet early Monday morning. However precipitation will become
more showery which should put a cap on the amount of snow for the
passes. Even so, snow covered roads for Diamond Lake, Lake of the
Woods, and Siskiyou Summit are likely.

Monday will be a transition day with the upper trough exiting out
with showers diminishing during the morning followed by increasing
dry time in the afternoon.

An upper ridge axis will build into the area Monday night and
continue into Tuesday. It will be dry, but with a subsidence
inversion, could lead to fog and low clouds for the interior
westside valleys.

There`s good agreement among the operational models and ensembles
the upper ridge axis will shift just east of the forecast area
Tuesday night as upper troughing over the eastern Pacific digs.
However the upper trough won`t make much progress east between
Tuesday night and Thursday. At the same time a front will slowly
nudge towards our forecast area during this time, but it will be
nearly parallel to the upper flow. Usually when this happens, front
will have a difficult time making much if any progress. looking f
further into the individual ensembles (ECMWF and GFS) and clusters
show the mean upper trough far enough offshore with a ridge presence
over our area. Given the above, the odds are in our favor of dry
conditions to continue during this time. -Petrucelli

&&

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

PACIFIC COASTAL WATERS...Small Craft Advisory until 10 PM PST Friday
     for PZZ350-356-370-376.

&&

$$