Freeze Warning 16, NWS Medford, OR

Area Forecast Discussion
National Weather Service Medford OR
857 AM PDT Tue Oct 16 2018

.DISCUSSION...The morning balloon sounding from Medford shows the
continued dry air mass, with humidity of 10 percent at 5000 ft
MSL. This is, amazingly, not as dry as yesterday morning which
featured 4 percent humidity at the same level. High terrain winds
are also trending lower compared to Monday morning but are still
gusty. Ridgetops in the Cascades are registering gusts in the 20s
(mph) this morning, and winds are gusting into the 30s in the
Siskiyous.

This dry air mass will continue through the week, and this will be
challenging for existing fires (Klondike, Stukel). Smoke will
result, and we've added some smoke in the forecast for the coast
south of Cape Blanco.

Please see the previous discussion below for more details on the
warm and dry weather this week and then the rain chances next
week. Keene

&&

.AVIATION...For the 16/12Z TAFs...VFR will persist through this
evening across most the area. Areas of LIFR/IFR cigs and visibility
are expected along the coast from Cape Blanco south this morning,
with clearing to VFR expected late this morning. Areas of LIFR/IFR
cigs may return again to the coast tonight. Inland, expect VFR
conditions through the TAF period except for local visibility
reductions from smoke in northern Curry County and southern Coos
County, for areas downwind of the Klondike wildfire. -CC

&&

.MARINE...Updated 300 AM PDT Tuesday 16 October 2018...Winds will
generally remain below 15 kts through at least Friday. Today,
persistent long period southerly swell of around 3 feet may produce
rough bar conditions at Brookings and elevated surf at Port Orford.
Aside from this persistent southerly swell, conditions will remain
relatively calm today.

Wednesday into Thursday, a longer period west to northwest swell at
16 to 18 seconds will build into the coastal waters. This will
combine with the aforementioned smaller long period southerly swell
and could make for hazardous bar conditions Wednesday into Thursday.
Overall, wave heights will remain below 10 feet as this is only a 7-
8 foot swell. But, given the longer period swell, surf conditions
could be a concern as well. Breaker heights of 10 to 12 feet are
possible Wednesday into Thursday and this could catch some beach-
goers off guard as this is a bit higher than what has been typical
for the past few weeks. As a result, a beach hazards statement
remains in effect. Swell will begin to diminish Thursday night as
the period shortens, then seas will subside through Saturday night.

Early next week, a front may move into the coast and west swell
dominated seas may increase. -CC

&&

.FIRE WEATHER...Updated 230 AM PDT Tuesday, 16 October 2018...
A very dry air mass remains in place today with breezy to gusty
easterly winds over the ridges. Today, easterly winds are still
expected to remain strong enough over ridges for red flag warning
conditions to continue for portions of western Siskiyou County and
the Siskiyous, but they will be lighter than they have been the last
two mornings. Winds over these areas will diminish below critical
levels by tonight, if not sooner. Tonight and Wednesday morning,
breezy east winds are expected to persist over the Cascades with
mainly light east winds over other ridges. Moderate to locally poor
recoveries are expected over the ridges tonight into Wednesday
morning.

As a light easterly flow persist into the weekend, daytime RHs are
likely to remain low across the area along with moderate to locally
poor recoveries on the ridges. Low daytime RHs today are expected to
nudge upward through Thursday, however. Light east winds could
increase some again Friday night into Saturday, though they are
likely to be much lighter than has been observed the last two days.
Forecasts from the GFS indicate a pressure gradient around 5 MB over
the area Saturday morning versus the previous couple days with 16MB
analyzed by the GFS for Sunday morning and 12MB for Monday and 8MB
today.

Then a pattern change is expected to bring higher RHs and, possibly,
some rain early next week. -CC

&&

.PREV DISCUSSION... /Issued 321 AM PDT Tue Oct 16 2018/

DISCUSSION...Cold temperatures remain the main feature for the
forecast period across southern Oregon and northern California.
We're currently watching temperatures fall below freezing in the
west side valleys, so the freeze warning and frost advisory will
likely verify this morning. Medford and Roseburg will likely see
some frost this morning given the current trend in temperatures
compared to yesterday.

As for Tuesday night, temperatures are expected to trend upwards
a few degrees, so more frost is probable for the west side
valleys, but we'll probably steer clear of freezing temperatures
in the usual cold spots in the Illinois and Applegate valleys.

Aside from the cold overnight temperatures, we're actually
expecting high temperatures to be around 10 degrees above average
for most of the week with this ridge of high pressure sticking
around. The pattern is rather stagnant, but that will probably
change around next Tuesday when both models are showing a low over
the Gulf of Alaska and precipitation arriving in the Pacific
Northwest.

The last thing we want to touch on is the Klondike fire becoming
active yet again. People will probably wonder where the smoke will
be heading for the next few days. This east off shore flow will
likely continue for today and into Wednesday, so the coast will
see the smoke the next two days. However, the winds will shift
Thursday allowing for the smoke to funnel into the west side
valleys and northern California.

The good news here is that hope is on the horizon. Both models
are showing a minor atmospheric river type event around next
Tuesday into next Thursday as mentioned above. This should result
in impactful measurable precipitation occuring along the coast up
to the Cascades between next Tuesday and next Thursday.

-Smith

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Beach Hazards Statement from late tonight through Wednesday
     evening for ORZ021-022.
     Frost Advisory until 9 AM PDT this morning for ORZ023-024-026.
     Red Flag Warning until 8 PM PDT this evening for ORZ621.
     Freeze Warning until 9 AM PDT this morning for ORZ024-026.

CA...Frost Advisory until 9 AM PDT this morning for CAZ080.
     Red Flag Warning until 8 PM PDT this evening for CAZ280.
     Freeze Warning until 9 AM PDT this morning for CAZ081-082.

Pacific Coastal Waters...Beach Hazards Statement from late tonight through Wednesday
     evening for PZZ350-356.