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fxus66 kmfr 231615 

Area forecast discussion
National Weather Service Medford or
915 am PDT Fri Jun 23 2017

Discussion...the coast is beginning to see cooler temperatures
this morning, starting south near Brookings, and this coastal
surge of cooler air will slowly move northward over the next 2
days. We have lowered Brookings forecast high today as they are
now seeing some onshore flow and temperatures have dropped 21
degrees over the past hour, from 85 to 64.

Sunny and hot will be the rule for inland locations
today through Sunday. Daily record high temperatures are possible
Saturday when temperatures will peak. Please see our web Page at
weather.Gov/Medford for a rundown of forecast high temperatures
and daily record values for Saturday and Sunday. The three days of
heat will present a significant risk for a large part of the
area's population. This is partly due to the fact that we're still
in early Summer and folks haven't acclimated to such high
temperatures yet. Additionally, overnight low temperatures will
not offer much relief from the heat (or at least not as much as
normal). Therefore, we have issued an excessive heat warning and
heat advisory for most inland areas west of the Cascades. Some
things to remember during the heat.

* Beat the heat, check the backseat. Never leave people or pets
in vehicles.

* Rivers are dangerously cold and have strong currents. Wear a
life jacket if swimming.

* Monitor older adults, Young children and those who are sick.

* Take plenty of rest breaks in shade or air conditioning.

* Drink water before, during and after activities.

Attention then turns to more fire weather impacts Sunday and
Monday as thunderstorm chances are introduced to the forecast.
After such hot and dry weather, lightning poses a significant
threat for new fires. We'll be spending time on thunderstorm
chances today and communicating these threats to land management

Please see the previous discussion below for more details on the
heat and thunderstorm potential.


Aviation...23/12z taf cycle...VFR conditions will continue at all
inland terminals through the taf period. There appears to be a good
chance for MVFR visibility in light fog to redevelop at oth after
04z this evening and worsen some toward 12z. Mts


Marine...updated 300 am Friday, 23 June 2017...little change to the
forecast today other than to end the Gale Warning a bit earlier
south of Cape Blanco. The strong thermal trough will be moving
inland this afternoon with a weakening pressure gradient over the
waters. Hazardous seas and Small Craft Advisory winds will continue
into tonight however. Saturday the north winds will weaken
considerably with seas remaining somewhat elevated beyond 5 nm from
shore. South flow prevails Sunday into Monday as low pressure moves
in from the southwest. Mts


Previous discussion... /issued 500 am PDT Fri Jun 23 2017/

Discussion...the forecast focus was on coastal temperatures for
the next two days. Have only made minor changes to inland
temperatures for the next few days. The big question is how warm
will the coastal cities get today and Saturday. The guidance was
showing the Brookings Airport reaching the mid to upper 80s today
and the temperature at 2 am was a balmy 83 degrees with a
northeast wind gusting to 33 mph. The hrrr high resolution model
shows winds turning onshore at Brookings today around 1 PM.
Therefore, have raised the high at Brookings to 89 degrees but the
exact climb upward has a lot of uncertainty.

Farther north, the Coos Bay area is also a challenging
temperature forecast. Northerly flow should allow some cooling
compared with inland areas and it was 54 degrees at 230 am. Have
raised the high temperature at the North Bend Airport to 75
degrees today and kept the 80 degrees for Saturday. The cooler
south-to-north surge of marine air may not make it that far north
until late on Saturday so there is the chance that temperatures
could climb through the 80s on Saturday.

The ocean temperatures are only in the upper 40s and lower 50s due
to strong upwelling (colder ocean water coming up from below) which
has occurred due to the recent gusty and persistent north winds.
These cold ocean temperatures will really be felt when the winds
turn onshore, especially when accompanied by low clouds and fog.

Elsewhere inland, it will be very hot with near record high
temperatures this weekend. Various excessive heat warnings and
heat advisories are in effect this weekend.

There will be a transition to cooler air early next week with
thunderstorms possible during this change of airmass. The upper
flow will become southerly on Sunday and the models have been
consistently showing convection and precipitation developing from
mainly the Cascades westward. The models have also shown the
convection continuing throughout the night so we could see an
unusual bout of isolated to scattered thunderstorms persisting
through the night.

On Monday the convection should focus farther east from around
the Oregon Cascades eastward as an upper trough comes through our
area by evening. Much of next week will feature temperatures
closer to normal with dry conditions as the upper westerlies
influence the Pacific northwest.


Mfr watches/warnings/advisories... flag warning until 10 am PDT this morning for orz618.
Heat advisory from 11 am Saturday to 8 PM PDT Sunday for
Excessive heat warning from 11 am Saturday to 8 PM PDT Sunday
for orz023>028.

California...heat advisory from 11 am Saturday to 8 PM PDT Sunday for
Excessive heat warning from 11 am Saturday to 8 PM PDT Sunday
for caz080-081.

Pacific coastal waters...Small Craft Advisory until 11 PM PDT this evening for
Small Craft Advisory for hazardous seas from 11 PM this evening
to 5 PM PDT Saturday for pzz350-356-370-376.
Hazardous seas warning until 2 PM PDT this afternoon for

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