412
FXUS66 KMFR 181130
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
414 AM PDT Sat May 18 2024

.UPDATE...Updated aviation discussion for 12z TAFs.

&&

.DISCUSSION...Model agreement is very good into Friday, with the
main points of uncertainty being the strength of a
seasonable/relatively weak trough Tuesday afternoon into Wednesday
night, and (with a larger extent of uncertainty) another at the
end of the forecast, around Friday night into next Saturday.

Today looks to be the warmest out of the next 7 days, with
readings near to several degrees above normal, which will be near
the levels reached yesterday. After a solid week of much warmer
and drier than normal weather, the shift to seasonable conditions
for the next week will be noticeable. The other main
characteristic, at least through Wednesday, will be continued
stronger than normal afternoon into evening breezes, with winds
mainly out of the west to northwest. Winds this afternoon will be
stronger than yesterday (with gusts at 15 to 30 mph), almost as
strong late in the day Sunday through Tuesday, then possibly at a
slightly stronger peak for Wednesday.

Regarding precipitation, the chances will be late tonight into
Sunday morning for Coos and northern Douglas counties with a few
hundredths of an inch possible, then first and most significantly
in that same area with the aforementioned cold front Tuesday
afternoon into Tuesday evening, extending across at least southern
Oregon Tuesday night into Wednesday with amounts mainly up to a
tenth of an inch. Some break between systems is likely Thursday,
then the next trough will move southeast into the Pacific
Northwest. There is a wide variety of solutions regarding the
southern extent and strength of this trough, with the possibility
of either a quick glancing blow of minimal impact or the necessity
of raising the current slight chances of precipitation. At the
least, temperatures Friday into the start of the Memorial Day
weekend are likely to be slightly below normal to near normal with
coastal highs near 60, lower 70s on the west side, lower to mid
60s on the east side, and mainly 50s in the mountains.

&&

.AVIATION...18/12Z TAFs...Clear skies and VFR conditions will
continue to dominate in the majority of the region this morning
through this evening. Per current satellite imagery, low stratus
associated with the marine layer has remained both further offshore
and more broken up than models suggested earlier today. Its not out
of the question that the marine layer could move closer to the coast
later this morning, but expecting the easterly component to winds
along the coast to keep conditions VFR.

Today, expecting another mostly clear day, though some higher clouds
will likely start to filter into the region from the north/northwest
ahead of a weak frontal system. Breezy winds will pick up ahead of
this boundary this afternoon into early this evening, with north to
northwest winds gusting to 20-30 kts through most of the region. The
weak front will then push the marine layer inland this evening into
the overnight period, with MVFR ceilings looking likely along the
Coos coast and possibly into the Umpqua Valley. Some of the higher
resolution models are suggesting this stratus could spillover some
into the Rogue Valley, but expect that these models are overdoing it
and have left it out of the Medford TAF. -CSP

&&

.MARINE...Updated 200 AM Saturday, May 18, 2024...A thermal
trough pattern will maintain gusty north winds and steep to very
steep seas through the weekend into early next week. Seas will be
highest south of Cape Blanco around Brookings with waves up to 10-12
feet today. Meanwhile, areas near Florence and Coos Bay will see
waves around 5 to 7 feet. Seas will be a combination of fresh swell
out of the northwest and wind waves.

Seas will remain hazardous to small craft through the weekend and
into early next week. The thermal trough will weaken slightly early
Sunday morning through the afternoon, but seas will remain steep
through the majority of the waters. It will then strengthen again
late Sunday into Monday, with yet more steep to very steep waves.
Waves will then subside to around 4 to 6 feet across all the waters
around Tuesday and Wednesday of next week. -CSP

&&

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

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

Hazardous Seas Warning until 2 AM PDT Sunday for PZZ356-376.

&&

$$