Severe Thunderstorm Warning 26, NWS Medford, OR

806 
WWUS56 KMFR 250101
SVSMFR

Severe Weather Statement
National Weather Service Medford OR
601 PM PDT MON JUL 24 2017

CAC049-250109-
/O.CAN.KMFR.SV.W.0026.000000T0000Z-170725T0115Z/
Modoc CA-
601 PM PDT MON JUL 24 2017

...THE SEVERE THUNDERSTORM WARNING FOR CENTRAL MODOC COUNTY IS
CANCELLED...
                
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore the warning has been cancelled. However gusty winds are 
still possible as this storm decays.

LAT...LON 4136 12069 4139 12085 4167 12082 4163 12057
TIME...MOT...LOC 0058Z 190DEG 21KT 4148 12076 

$$

BPN

Area Forecast Discussion
National Weather Service Medford OR
238 PM PDT Mon Jul 24 2017

.DISCUSSION...An upper low will continue to spin off the California
Coast for the next couple of days bringing increasing moisture,
instability, and multiple shortwaves resulting in isolated to
scattered thunderstorms. The upper low will slowly move inland on
Wednesday with a continued chance of thunderstorms. The most active
days will be this afternoon, Tuesday and Wednesday before dry
weather returns Thursday.

The latest water vapor image shows the upper low spinning off the
California Coast near Point Arera. Ahead of the low there is plenty
of instability and multiple shortwaves which are allowing storms to
light up. Right now, storms are mostly confined to Modoc County, but
storms are already starting to develop in portions of Lake and
eastern Kalamth Counties. The latest short range high res HRRR run
has been consistent showing storm development in these areas during
the afternoon and evening. Storms will to continue develop and
migrate north to northeast later this afternoon into this evening
with south winds between 10-15 kts mainly affecting Lake and Klamath
County. However, could not rule out storms developing along the
Cascades and portions of the Siskiyous late this afternoon with the
latest mesoscale analysis showing surface based capes between 1500
and 2000 J/kg. Additionally, some of the models show lots of
instability even here in the Rogue Valley (>1000 J/KG). While we
can't completely rule out an isolated storm on the west side, model
soundings also show significant CIN (convective inhibition) and this
will be the main limiting factor to any convection west of the
Cascades. Storms today should be a bit wetter with PW values
everywhere in the 0.75-1.00" range late this afternoon, increasing
to 1.00-1.25" by this evening. Showers and isolated thunderstorms
could linger through the nighttime hours, but most should dwindle
again with the loss of instability.

Another active day is in the cards on Tuesday and could be the most
active days in terms of thunderstorm coverage and chances. The upper
low will remain just off the California coast, but it will tap into
more moisture. Instability is still greatest along and east of the
Cascades, but there is some evidence portions of the westside,
including the Rogue and Illinois Valleys could see more frequent
storms. Once again CIN is expected to be high, so we could miss out
again. Also there is a better chance for wetting rains as PWATS are
expected to increase with a swath of 1+ inches along and east of the
Cascades and portions of Northern California Tuesday afternoon. Also
winds at 700mb will be lighter, therefore storms could be slow
movers which means there is the potential for some of these storms
to produce moderate to heavy rain.

Nocturnal storms again are possible along with lingering overnight
showers and some remaining cloud cover Tuesday night as the upper
low slowly moves onshore and multiple shortwaves rotate ahead of it.
Right now it's unclear how the area of storms shapes up, but we
could see a fair amount of activity.

Wednesday will be another active days as the upper low slowly moves
inland and opens up. All of the ingredients for thunderstorms will
be present again. However as the low/upper trough shifts east
Wednesday afternoon, we expect most of the action to also shift east
of the Cascades. However, keep in mind the models have been trending
slower with the inland progression of the upper low/trough,
therefore the details on this could change.

Dry weather will return Thursday and could last through next
weekend. A southwest flow will remain over our area with the ridge
centered near the four corners, but 500mb heights will gradually
increase and we could see temperatures get close to triple digits
for inland west side locations and low to mid 90s east of th e
Cascades. The models show the ridge retrograding west towards our
area next Sunday weekend into early next week with continued hot
temperatures for inland locations. -Petrucelli

&&

.AVIATION...24/18Z TAF CYCLE...Along the coast and over the coastal
waters.  Areas of MVFR/IFR cigs over the waters will spread back
onshore this evening and into the lower Umpqua Basin tonight...then
burn back to the coast by late Tuesday morning. KOTH will be
affected by the lower conditions but at this time it looks like KRBG
will not be.  Over the remainder of the area...VFR conditions will
prevail through Tuesday...but so will isolated to scattered
thunderstorm activity...especially east of the Cascades. Gusty winds
and local obscuration of higher terrain will be likely near
thunderstorms. -JRS

&&

.MARINE...Updated 200 PM PDT Monday 24 July 2017...A thermal trough
will continue to produce gusty north winds and steep to very steep
seas through Tuesday, with gales south of Cape Blanco persisting
into Tuesday morning. The thermal trough will weaken mid week, and
winds will diminish slightly, but seas will remain elevated as
residual wind seas and fresh swell remain. At least small craft
conditions will remain in the area through Thursday. With weaker
thermal troughing then continuing through the weekend, somewhat
marginal winds and seas are expected into early next week, but small
craft conditions will be possible at any time. -BPN

&&

.FIRE WEATHER...Updated 230 PM Monday 23 July 2017...Currently
thunderstorms are limited to Modoc and Lake counties. There is more
moisture to work with today so lightning frequency should increase
as well. In addition, models are pointing to an area from eastern
Modoc north into Strawberry/Coffeepot RAWS then east into Harney
County where storms could produce wetting rain. This area is covered
by an LAL of 4. Southeast flow aloft continues and storms that form
in Siskiyou County could drift into southern Jackson County tonight.
Ashland may be affected but Medford is much less likely to see any
activity. Models also bring these storms into the Cascades around
this evening. SE flow could bring these storms into the west slope
of the Cascades this evening and tonight. Confidence is higher today
that the eastern Umpqua NF and High Cascade Fire Zone could see
thunderstorms tonight.  Thunderstorm activity will continue through
Tuesday and spread farther west...affecting just about everywhere
except the coast.

Thunderstorm potential covers a much larger area than described in
the Fire Weather Warning/Watch. The area reflects forecasted LALs of
3 or more. The thunderstorm threat will diminish Wednesday afternoon
and evening as the upper low moves out to the east of the area and
westerly flow develops over the area. This however will likely lead
to breezy west winds during the second half the week.

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Red Flag Warning until 11 PM PDT Tuesday for ORZ617-622>625.
     Fire Weather Watch from Wednesday morning through Wednesday
     evening for ORZ617-623>625.
     Red Flag Warning from 11 AM to 11 PM PDT Tuesday for ORZ620-621.

CA...Red Flag Warning until 11 PM PDT Tuesday for CAZ284-285.
     Fire Weather Watch from Wednesday morning through Wednesday
     evening for CAZ280-281-284-285.
     Red Flag Warning from 11 AM to 11 PM PDT Tuesday for CAZ280.

Pacific Coastal Waters...Small Craft Advisory until 5 AM PDT Wednesday for
     PZZ350-356-370-376.
     Gale Warning until 8 AM PDT Tuesday for PZZ356-376.
     Hazardous Seas Warning until 5 AM PDT Wednesday for PZZ356-376.
     Small Craft Advisory for hazardous seas from 8 AM Tuesday to 5
     AM PDT Wednesday for PZZ350-370.
     Hazardous Seas Warning until 8 AM PDT Tuesday for PZZ370.

Special Weather Statement
National Weather Service Medford OR
325 PM PDT MON JUL 24 2017

ORZ030-031-242315-
Central and Eastern Lake County OR-
Northern and Eastern Klamath County and Western Lake County OR-
325 PM PDT MON JUL 24 2017

...SPECIAL WEATHER STATEMENT...

At 324 PM PDT, Doppler radar was tracking a cluster of strong
thunderstorms near Paisley, or 37 miles northwest of Lakeview,
moving northeast at 5 mph.

Half inch hail and winds in excess of 30 mph will be possible with
this storm, as well as frequent lightning and periods of heavy
rainfall.

Locations impacted include...
Paisley, Hadley Snow Park, Chewaucan Crossing Trailhead, Currier
Spring Trailhead and Marster Spring Campground.

* This includes...
   Highway 31 in Oregon between mile markers 85 and 108.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

&&

LAT...LON 4256 12071 4274 12083 4288 12055 4255 12040
      4250 12051
TIME...MOT...LOC 2224Z 213DEG 7KT 4267 12068

BPN

Special Weather Statement
National Weather Service Medford OR
514 PM PDT MON JUL 24 2017

ORZ030-250100-
Northern and Eastern Klamath County and Western Lake County OR-
514 PM PDT MON JUL 24 2017

...SPECIAL WEATHER STATEMENT...

At 513 PM PDT, Doppler radar was tracking a strong thunderstorm 8
miles northwest of Head Of The River Campground, or 32 miles east of
Crater Lake, moving northeast at 5 mph.

Half inch hail and winds in excess of 30 mph will be possible with
this storm, as well as frequent lightning and periods of heavy rain.

Locations impacted include...
Antler Campground And Trailhead.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

&&

LAT...LON 4273 12148 4284 12160 4301 12138 4294 12119
TIME...MOT...LOC 0013Z 209DEG 8KT 4284 12149

BPN