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000
FXUS66 KMFR 212338
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
437 PM PDT Sun Apr 21 2024

Updated AVIATION Section

.DISCUSSION...Aside from some high level cirrus clouds streaming
over the region, skies are clear across the area this afternoon
and temperatures are running about 5 to 10 degrees cooler than
this time yesterday. Overall, it`ll be pleasant spring afternoon
for the area, with high temperatures peaking near seasonal normals
today -- upper 60s/low 70s West Side and low to mid 60s East
Side. Gusty north winds have kicked in along the coast due to a
strengthening thermal trough. This thermal trough will induce east
to northeasterly flow today and Monday, resulting in the Chetco
Effect and warmer temperatures (compared to the rest of the
coastal locations) in the Banana Belt region. Dry conditions are
expected to continue across the region today and through Monday
before a subtle shift in the weather occurs Tuesday and Wednesday,
and a more notable change in the pattern occurs for the latter
half of the week and into next weekend.

Zonal flow is in place today, but a shortwave ridge will pass
through the region Monday. This, along with the thermal trough
pushing inland, will bring a sharp jump in high temperatures on
Monday. Expect afternoon temperatures to be about 5 to 10 degrees
warmer than what is expected today, along with unseasonably low day
time humidities. The Chetco Effect will peak Monday, and locations
along the southern coast (Brookings, Gold Beach) are expected to
reach into the upper 70s before the flow reverses and the cooler air
from the Pacific returns.

Tuesday into Wednesday, the upper level pattern will transition with
low pressure developing out near 130 W west of the California coast
and low pressure pushing toward the British Columbia Coast. This
will put our region in southwest flow and some mid level moisture
will move into the area. This combined with some model indicated
instability (-2 to -4 LIs, 300-500 J/kg CAPE) is boosting confidence
in thunderstorm potential for Tuesday and Wednesday. The focus for
thunderstorm potential will be over northern California and in the
southern half of Klamath and Lake Counties on Tuesday, then a bit
farther east on Wednesday over eastern Siskiyou, Modoc and southern
Lake Counties. For the remainder of the area, conditions will remain
dry though expect an uptick in afternoon winds and cloud cover with
temperatures trending cooler.

Thursday into next weekend, the pattern turns cooler and wetter with
a front expected to push onshore late Thursday morning and move
through the region through the day. The upper level trough will be
reinforced by another trough, deepening and digging in along the
West Coast into the weekend. This will maintain a cool and showery
pattern, with most, if not all, of the area seeing a good chance of
rain at some point before the end of the forecast term. /BR-y

&&

.AVIATION...22/00Z TAFs...VFR will prevail for the next 24 hours,
albeit with some high cirrus. Gusty north winds along the coast (up
to 30 kt) and in the Umpqua Basin (around 20 kt) will subside this
evening, but expect similar winds to redevelop in the same areas
Monday afternoon/evening. -Spilde

&&

.MARINE...Updated 215 PM Sunday, April 21, 2024...High pressure
is building in and will remain just offshore with a thermal trough
developing along the south coast. North winds are increasing across
the waters with moderate to strong winds, reaching gale force south
of Bandon through Monday evening. This is also the same time period
when these winds will expand north of Cape Blanco, widening the
footprint of steep to very steep wind-driven seas to all the waters.

Conditions are likely to improve Tuesday into Wednesday ahead of the
next cold front expected on Wednesday night into Thursday.
/BR-y/Hermansen

&&

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

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

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

&&

$$

MNF/ANH/MAS