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000
FXUS66 KMFR 032159
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
259 PM PDT Wed Jun 3 2020

.SYNOPSIS...Warm, dry weather will continue through Thursday.
There is a chance of showers just about everywhere by late Friday
afternoon/evening with a slight chance of thunderstorms east of
the Cascades. Then, low pressure will move in this weekend
resulting in another period of cooler, wetter weather and a
chance of thunderstorms.

&&

.DISCUSSION...Warm, dry conditions will continue this afternoon
and evening with some high clouds at times, especially from the
Cascades eastward. Fairly typical north to northwest breezes
(gustiest along the coast) will also continue into the early
evening hours before easing later on. Aloft, the flow is zonal
across the PacNW with a closed low meandering off the southern
California coast. Other than patchy low clouds/fog along the coast
and into the Umpqua tonight (and those pesky high clouds), most
areas will be clear. We`ll remain dry and warm across the area on
Thursday with temperatures very similar to today -- highs largely
ranging from the upper 70s to the 80s, but with some readings in
the 90s in the lower Klamath River Valley near Happy Camp and a
few 60s along the coast and in the mountains.

Another closed low will then dig southward from the Gulf of Alaska
Thursday night into Friday. The flow aloft will become more
southwesterly and with increasing moisture advection and
instability, we expect at least a chance of showers in the late
afternoon and evening with a slight chance of thunderstorms near
and east of the Cascades extending back to around the Mount Shasta
region. Models are showing CAPE of 250-500 J/KG over there, so
not a big deal, but enough to support a slight chance. Increased
cloud cover and a slight cooling of the air mass aloft should
result in temperatures at least a few degrees lower than on
Thursday.

It seems we`re on the weekend plan around here at least with
respect to incoming wet systems. The closed low digging
southeastward from the Gulf of Alaska will then move to a position
just off the WA/OR coast on Saturday, then move onshore Saturday
night and inland east of the Cascades on Sunday. While this
system will once again bring cooler weather with widespread
showers and a chance of thunderstorms, this one is more typical
for late spring and shouldn`t be anything like the impressively
wet system we had west of the Cascades last Saturday. Even so, it
will be cooler and wetter, so those that have outdoor plans like
graduation ceremonies, camping or otherwise, should keep checking
the forecasts for updates and adjust accordingly. The big
temperature drop will occur Saturday with temperatures about 15-25
degrees lower (inland) than on Friday. Temperatures both Saturday
and Sunday will be in the 50s and 60s in most places, but the
mountains will have highs only in the 30s and 40s! Snow levels
will lower down to around 4500 feet Saturday night. We`re not
expecting accumulating snow that low, but there could be some
flakes in the air.

Once this system moves away Sunday night and skies clear, expect
it to get quite cold by Monday morning, especially in the
typically colder valleys in northern California and east of the
Cascades. Right now, we`re expecting lows in the upper 30s to mid
40s here in the Rogue/Illinois Valleys, but the Shasta Valley,
Klamath Basin and other areas of the east side will have
temperatures down near or even below freezing. The storm track
favors areas to the north and west of us toward mid next week, but
we`ve maintained a chance of showers from the Cascades westward,
but especially north and west of the Umpqua Divide. Temperatures
should rebound back to levels more typical of early June. -Spilde

&&

.AVIATION...For the 03/18Z TAF Cycle...Over the coastal waters and
along the coast...VFR conditions will prevail through at least this
evening with gusty northwest to north winds developing this
afternoon and evening.. Expect the return of MVFR/IFR cigs offshore
tonight that will persist into Thursday morning. Some IFR to LIFR
cigs may move onshore late tonight, mostly north of Cape Blanco.
However, confidence in exact location and timing is low. Elsewhere,
VFR conditions will prevail into Thursday morning. /BR-y


&&

.MARINE...Updated 130 PM PDT Wednesday 3 June 2020...Gusty north
winds will persist through Thursday, resulting in steep to very
steep and hazardous wind driven seas. The strongest winds and
steepest seas are expected south of Cape Blanco through Thursday,
then conditions will improve Friday. Low pressure moves into the
area Friday and will persist through the weekend. Winds and seas
will remain below advisory levels, but expect gusty west to
southwesterly winds during this time. Showers and isolated
thunderstorms are expected over the weekend.

Beyond the weekend, conditions continue to look relatively calm with
generally southerly winds prevailing. A weak front may brush by to
the north Monday into Tuesday and this may result in some advisory
level winds. /BR-y

&&

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

CA...None.

Pacific Coastal Waters...Small Craft Advisory until 5 AM PDT Friday
     for PZZ356-376.
     Hazardous Seas Warning until 5 AM PDT Friday for PZZ356-376.
     Small Craft Advisory until 5 AM PDT Friday for PZZ350-370.

$$

MAS/MAP/MNF