NWS Medford, OR wrote its last area forecast discussion before the first event at Jun 28, 1:52 PM PST, 1 hour 8 minutes earlier.
Area forecast discussion, Jun 28, 1:52 PM PST, 1 hour 8 minutes before
Area Forecast Discussion
National Weather Service Medford OR
252 PM PDT Mon Jun 28 2021
.DISCUSSION...The historic heatwave continues over southern
Oregon and northern California. We set several daily and monthly
records yesterday, as well as a couple of all time records, and we
will likely see more of the same today. If there is some good
news, high temperatures will be about the same or relatively
cooler than yesterday west of the Cascades, and some gradual
lowering of temperatures is expected through the rest of the
week. East of the Cascades, its more of the same or perhaps
slightly warmer today as the thermal trough and high pressure
shift farther east. They should also see the same gradual lowering
of highs through the week. We hesitate to use the word "cooling,"
as it will still be quite hot, just not as much so. Remember, the
heat itself is exceptional, but the duration of this event is
also notable. Model guidance suggests that we will stay at or
above 100 degrees in Medford through the weekend, and maybe even
into early next week. If we maintain through Sunday, we will tie
the record for consecutive 100 degree days in Medford at 10, and
if we keep 100 degree highs into Monday, we set a new record.
The Excessive Heat Warning remains in effect through Thursday,
and will likely be extended out into next weekend, although some
areas may be trimmed off the warning area as conditions improve.
See the Warning Message at PDXNPWMFR for details.
For those looking to escape the heat, the coast is still a great
destination as temperatures should stay in the lower 70's to upper
60's throughout the heatwave. Area lakes and streams may also
provide some relief. For those seeking to escape the heat in area
waters, make sure to take all the proper precautions and wear
life jackets, as cold water, swift currents, and surf can injure
or kill any time of year.
There are a few other talking points other than the heatwave and
high temperatures for the next few days. First, the Lava Fire is
burning with great intensity today, as can be seen on satellite
channels and fire weather cameras. Smoke then becomes a forecast
challenge, especially since it can influence surface temperatures.
With the atmosphere very well mixed in the afternoon, we're not
expecting smoke concentrations to become significant near the
surface, especially farther away from the fire. However, one may
see smoke elevated aloft or hazy skies through the rest of the
week.
The last topic we wanted to discuss is the potential for
thunderstorms east of the Cascades from Tuesday afternoon through
the rest of the week. Monsoonal moisture is moving north into our
area, and this will allow for the possible development of
thunderstorms as early as tomorrow afternoon in Modoc County, with
chances spreading into other portions of the East Side and
northern California each afternoon through the rest of the week.
Confidence in the exact timing and location of any convection is
low, but improving, as the models better hone in on the forecast.
Any smoke in the area, or any clouds from increased clouds and
thunderstorm activity due to the monsoonal flow, could provide
just enough cover to limit daytime heating late in the week, and
thus keeping temperatures a bit lower than we currently expect.
Confidence is low for either of these effects, but it is worth
keeping an eye on. Effectively, the price for slightly cooler
temperatures late next week could come at the cost of deteriorated
air quality, or the increased chances for lightning and all the
fire concerns that come along with it. -BPN
&&
.AVIATION...For the 28/18Z TAF Cycle...Inland, away from the coast,
VFR conditions will prevail through the next 24 hours. The exception
will be in mainly eastern and northern portions of the Shasta Valley
and surrounding mountains, which will see VIS obstruction from smoke
due to the Lava Fire east of Weed along the NW side of Mount Shasta.
This smoke could settle into a wider area of the Shasta Valley
overnight into Tuesday morning. Along the coast and over the coastal
waters, IFR/LIFR conditions will erode along portions of the coast
late this morning into the afternoon, but some IFR areas will likely
linger into the afternoon along the Curry County coast near
Brookings as well as north of Gold Beach. IFR to MVFR stratus is
expected to return to the coastal valleys again this evening into
early Tuesday morning. ~BTL
&&
.MARINE...Updated 800 AM PDT Monday 28 June 2021...Offshore low
pressure is bringing south winds and steep seas north of Gold Beach.
The winds will peak this evening between Cape Arago and Gold Beach,
but seas will remain steep through Tuesday as the low tracks
northward. A thermal trough will then strengthen along the coast,
and north winds will develop by Wednesday. Winds will be strongest
south of Cape Blanco with steep to very steep seas likely later
Wednesday into Thursday evening. This pattern will persist but will
weaken slightly late this week.
&&
.FIRE WEATHER...Updated 230 PM PDT Monday 28 Jun 2021...Hot
temperatures, low humidities and gusty winds are creating red flag
conditions over the Shasta and Scott valleys in northern California,
along with a Haines Index of six over the Lava and Cutoff fires. Hot
weather will persist through the coming week. Another Red Flag
Warning has been issued for the Cutoff fire Tuesday due to a
forecast Haines Index of six. Monsoonal moisture will filter into
the area, bringing isolated afternoon and evening thunderstorms east
of the Cascades beginning Wednesday and spreading into the Siskiyous
Friday.
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Excessive Heat Warning until 11 PM PDT Thursday for ORZ023>031.
Red Flag Warning until 9 PM PDT this evening for ORZ624.
Red Flag Warning from 8 AM to 9 PM PDT Tuesday for ORZ624.
CA...Excessive Heat Warning until 11 PM PDT Thursday for CAZ080>085.
Red Flag Warning until 9 PM PDT this evening for CAZ280-281.
Pacific Coastal Waters...Small Craft Advisory until 5 AM PDT Tuesday for PZZ356-376.
Small Craft Advisory until 8 PM PDT Tuesday for PZZ350-370.