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000
FXUS66 KMFR 221027
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
327 AM PDT Mon Apr 22 2024

.DISCUSSION...Very warm temperatures and dry conditions are
expected today. Highs will be 10 to 20 degrees above normal today.
Downslope easterly winds will also bring a mild Chetco effect with
warmer temperatures along the southern/central Curry coast today,
followed by cooler and cloudy conditions along these coastal areas
tonight and Tuesday as southerly flow develops. For inland areas,
the warm temperatures continue on Tuesday and into Wednesday.
Additionally, a shortwave trough approaching the Pacific Northwest
and an upper low to the southwest off the southern California
coast will result in moist mid level flow into the area with
chances for showers and thunderstorms.

Models and ensembles indicate unstable conditions on Tuesday
afternoon and evening, favorable for isolated to scattered
thunderstorms (15-25% chance) along with rain showers (20-40%
chance). National Blend of Models and high resolution ensembles
(HREF) indicate the favored area for thunderstorm development on
Tuesday will be across much of Siskiyou and Modoc Counties as well
as southern Klamath and southern/central Lake counties. A slight
chance for thunderstorms (15%) extends into southeast Jackson
County as well.

As the trough moves inland Wednesday, expect slightly cooler
daytime temperatures with additional chances for showers (20-40%)
and a slight chance for thunderstorms (15-20%) across northern
California zones and into portions of Klamath and Lake counties.

Then, the pattern chances with cooler, breezy, and wetter weather
developing Thursday and Friday as a frontal system and deepening
upper trough move into the region. Models and guidance are in good
agreement that daytime temperatures will trend much cooler with
highs 5 to 10 degrees below normal. Ensemble models indicates
precipitation is likely from the Cascades west on Thursday, then
spreading inland across the area Thursday evening through Friday.
Precipitation amounts are forecast to be light, except for a
potential of moderate precipitation along the coast, coastal
mountains, and into the Southern Oregon Cascades. Snow levels are
forecast to be around 5500 to 6500 feet during this period and
locally down to around 5000 feet on Friday. Additionally, as the
upper trough deepens over the area on Friday, cold air aloft will
result in unstable conditions with a slight chance for
thunderstorms (15-20%) across eastern Siskiyou, southeast Klamath,
Lake and Modoc counties.

As the upper level trough shifts east of the area, may see a
relative break in the wet weather with decreased shower chances
Friday night. Ensembles then favor cooler, breezy/windy, and wet
weather on the weekend with a frontal system approaching the
Pacific Northwest Saturday then moving inland Sunday. This will
likely result in cooler conditions along with chances for
precipitation. Snow levels may lower to 4500 to 5500 feet at times
Saturday and Sunday, mainly during the overnight and morning
hours. However, models show variability in the timing and strength
of this frontal system. So confidence is low in the exact timing
and precipitation amounts.

&&

.AVIATION...22/06Z TAFs...VFR will prevail for the next 24 hours,
albeit with some high cirrus. Gusty north winds will redevelop
Monday afternoon along the coast (up to 30 kt) and in the Umpqua
Basin (up to 20 kt), then gradually subside Monday evening.
-Spilde

&&

.MARINE...Updated 1245 AM Monday, April 22, 2024...A thermal
trough will maintain moderate to strong north winds and steep to
very steep wind driven seas late this evening. The strongest winds
and steepest seas are expected south of Cape Blanco. The thermal
trough will weaken tonight into Tuesday. Weaker north winds will
persist in most areas on Tuesday, but a southerly surge of stratus
could reach up to around Gold Beach, limiting visibility. Conditions
will improve with lighter winds and lower seas on Wednesday. The
next period of unsettled weather is expected Wednesday night through
Friday as a front moves through the region bringing rain showers, a
low chance for isolated thunderstorms; and behind the front, swell
dominated seas.
-Spilde/Miles


&&

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

PACIFIC COASTAL WATERS...Gale Warning until 11 PM PDT this evening
     for PZZ350-356-370-376.

Small Craft Advisory until 11 PM PDT this evening for PZZ350-
     370.

&&

$$

CC