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Office: MFR
FXUS66 KMFR 012325
AFDMFR
Area Forecast Discussion
National Weather Service Medford OR
425 PM PDT Tue Jul 1 2025
.UPDATE...Updated Aviation Discussion.
&&
.AVIATION...02/00Z TAFs...Along the coast, from Cape Blanco north,
IFR/LIFR ceilings and IFR/MVFR visibilities are expected through
Tuesday morning. Then, expect clearing to mainly VFR with local
IFR/MVFR Tuesday afternoon. Strong, gusty north winds are expected
(up to ~30kt) through this evening, strongest south of Cape Blanco.
Inland, VFR will prevail. However, coverage of showers and
thunderstorms will increase into this evening, especially from the
Cascades and Siskiyou Mtns south and east. Strong gusty erratic
outflows of 30-50 kts possible with these storms along with hail.
There is a low chance (20%) for thunderstorm to move near or into
Medford this evening. So have kept mention of VCTS in the TAF.
Lightning probabilities are lower in Roseburg (5%), but higher in
Klamath Falls (~55%).
&&
.PREV DISCUSSION... /Issued 156 PM PDT Tue Jul 1 2025/
DISCUSSION...Low pressure near the SF Bay area continues to send
moist, southerly flow northward into NorCal and SW Oregon.
Instability is increasing this afternoon due to daytime heating
and we're seeing thunderstorms initiate now. These will increase
in coverage through the afternoon and into this evening. As
mentioned earlier today, steering flow for storms is on the weak
side, so storm motion should be slow (5-15 mph), in a general SE
to NW fashion, but with more of a bending toward the SW in
southern portions of the forecast area (Siskiyou County). Storms
that initiate farther north along the Cascades or in the Highway
97 corridor in Klamath County should propagate more toward the
north. Focus for lightning will be in Siskiyou and western
Modoc/Lake Counties, but also northward into Klamath County and up
the Cascades through about 9 pm or so this evening. Lightning
risk isn't negligible west of the Cascades, but convective
inhibition of 100-300 J/KG should be a limiting factor as to just
how much can really get going and how far west. As it stands,
there is a low probability (~20% chance) of a thunderstorm nearby
the Rogue Valley late this afternoon/evening, but storms are more
likely to affect eastern portions of Jackson County and remain in
the Cascades/Foothills and closer to Butte Falls/Prospect. Main
storm risks through this evening will be strong, gusty outflow
winds due to dry sub-cloud layer and DCAPE in the 1000-1500 J/KG
range as well as small hail and numerous cloud to ground flashes.
With more lightning expected, expect new fire ignitions. Fire
weather discussion below will cover the specifics.
After sunset this evening, the atmosphere will begin to stabilize
and thunderstorms will transition to showers, gradually ending
overnight into Wednesday morning.
The low that is moving into California will continue to move
slowly inland Wednesday afternoon south of Lake Tahoe. This should
bring more of WSW flow aloft from the Cascades westward to end
the risk of lightning in those locations. It will also result in
some gusty afternoon upvalley NNW breezes (15-25 mph) and a drying
air mass. However, the trough axis to the north of the low will
still move through areas east of the Cascades. As such, we are
expecting another round of showers and scattered thunderstorms
over there, primarily from eastern Klamath/Siskiyou counties to
Lake and Modoc counties (just east of Klamath Falls and also
probably just east of Mt. Shasta, though instability could cause
one or two to pop up back to northern Trinity County). A Red Flag
Warning has been issued and should also be detailed in the Fire
Weather section.
Thursday through the 4th of July, another couple of short wave
troughs will swing through in westerly flow aloft. The first will
push onshore into NorCal late Thursday and Thursday night with the
second moving quickly into Oregon behind it on Friday.
Instability and moisture will remain highest in NE Cal and areas
east of the Cascades. So, we have maintained a chance of showers
and thunderstorms for portions of Klamath/Lake and Modoc counties.
It should remain dry though west of the Cascades. Could be some
marine cloudiness each morning/night near the coast. Overall,
with cooler air aloft, most areas should see high temperatures
those days within a few degrees of normal. This means highs in the
low to mid 80s for the valleys west of the Cascades and in the
upper 70s to low 80s over the East Side.
We should be between systems on Saturday. Temperatures edge back
to slightly above normal levels. However, yet another disturbance
will move toward the area. Moisture and instability are modest at
best with this system, so most guidance is not showing any
precipitation. But, we may need to adjust should future model
runs increase these parameters.
Next week, models show a trough (weak closed low?) hanging around
Monday/Tuesday near/just off the NW California coast, but then
the Four Corners high strengthens and retrogrades mid-late week.
This should bring a return of hotter weather with NBM guidance
showing mean high temps in the upper 90s and lower 100s for the
valleys west of the Cascade. -Spilde
AVIATION...01/18Z TAFs...Along the coast, from Cape Blanco north,
ceilings and visibility will waver from IFR to MVFR this
afternoon. Strong, gusty north winds are expected (up to ~30kt)
through this evening. Expect IFR/LIFR to impact North Bend
overnight into Wednesday morning.
Inland, VFR will prevail. However, coverage of showers and
thunderstorms will increase, especially from the Cascades and
Siskiyou Mtns south and east. Strong gusty erratic outflows of
30-50 kts possible with these storms along with hail. We've
indicated VCTS at Medford this evening. Think most activity is
east of the airfield, but there is a low probability (around a 20%
chance) of a thunderstorm. Lightning probabilities are lower in
Roseburg (5%), but higher in Klamath Falls (~50%). -Spilde
MARINE...Updated 200 PM PDT Tuesday, July 1, 2025...Gales and very
steep seas will continue through this evening south of Cape Blanco,
with small craft advisory winds and seas to the north. Conditions
will very gradually improve over the next 24 to 48 ours, with gales
ending tonight, but gusty north winds and steep seas continuing
through Wednesday. After a brief period of calmer conditions
Thursday into Friday, the thermal trough returns this weekend, along
with strong north winds and steep to very steep seas. -BPN
FIRE WEATHER...Updated 230 PM PDT Tuesday, July 1, 2025...
Thunderstorms continue to be the main concern. After nearly 1000
cloud to ground strikes yesterday, we expect to see another round of
thunderstorms this afternoon and evening, mainly along and east of
the Cascades, followed by more thunderstorms Wednesday afternoon and
evening, again mainly east of the Cascades. A Red Flag Warning
remains in effect for FWZs 280, 281, and 284 today, but areas east
still remain in moderate fire danger, so no warnings have been
issued there for today. However, these areas will be going to high
fire danger at midnight tonight, so a Red Flag Warning has been
issued for FWZs 284, 285, 624, and 625 due to the next round of
lightning Wednesday afternoon and evening.
We picked up a few more lighting strikes in Klamath and Lake
counties this morning, but conditions have calmed over the last few
hours, with Radar showing only showers as of this writing. We still
expect thunderstorms to develop in just a few more hours, aligning
with max heating this afternoon and evening. Storms today should
behave much like yesterday, with storms early this afternoon perhaps
not producing much of any precipitation to start, then the chance
for wetting rain could increase mid to late this afternoon and
evening. The main reason for the increase chance in wetting rain is
steering winds will be light and high moisture content throughout
the column of the atmosphere. Thus, storms will be slow movers
providing the bigger window of opportunity for storms to produce
locally moderate to heavy precipitation. However, that does not mean
that all storms will produce wetting rain. Some could also produce
little to no rain, because of the dry sub layer below.
Keep in mind, lightning strikes outside of the precipitation cores
are possible. Due to the prolonged period of dry and warm to hot
weather, lightning efficiency will be high to very high for fire
starts. We also have to be mindful of gusty and erratic outflow
winds near and away from the core of thunderstorms.
A few models suggest that some isolated thunderstorms could continue
into the late evening or overnight hours, but as is typical for
these types of situations, confidence on this is low and it will be
something that we'll need to monitor as it occurs.
It should be noted that any residual cloud cover from nightime or
morning convection, much like we have seen across some of the area
east of the Cascades today, could easily reduce thunderstorm chances
by blocking solar heat and therefore reducing instability. This is
not easily predictable until it occurs, and would be the primary
reason the forecast may not turn out as expected.
Although the trough responsible for these past several days of
convection will kick off to the east by Wednesday night, the concern
for thunderstorms could carry over into Thursday as an upper trough
approaches the area from the west. The best chance for storms
Thursday would be along and around the Warners in Lake and Modoc
counties. -BPN
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Red Flag Warning from 2 PM to 8 PM PDT Wednesday for ORZ624-625.
CA...Red Flag Warning until 8 PM PDT this evening for CAZ280-281-284.
Red Flag Warning from 2 PM to 8 PM PDT Wednesday for CAZ284-285.
PACIFIC COASTAL WATERS...Small Craft Advisory until 5 AM PDT Thursday
for PZZ356-376.
Small Craft Advisory until 11 AM PDT Wednesday for PZZ350-370.
Gale Warning until 11 PM PDT this evening for PZZ356-376.
&&
$$
CC/CC/CC
Office: PQR
FXUS66 KPQR 012217
AFDPQR
Area Forecast Discussion
National Weather Service Portland OR
317 PM PDT Tue Jul 1 2025
.SYNOPSIS...Hot and dry weather continues today, though cooler
than Monday. Highs will still reach into the upper 80s to around
90 degrees across the interior. Isolated thunderstorms remain
possible across the Lane and Linn County Cascades this afternoon
through tonight. A cooling trend begins tomorrow, bringing more
seasonable conditions through the weekend. There are signs that
warmer temperatures may return early next week as upper level
ridging begins to rebuild.
&&
.DISCUSSION...Tuesday Afternoon through Monday...Radar imagery at
2 PM PDT on Tuesday afternoon shows scattered thunderstorms have
formed just to the south and to the east of Lane County. SPC
mesoanalysis depicts a shortwave along the low pressure system
lingering over California has brought moisture into central Oregon,
with elevated RHs at 925 mb and 850 mb. Guidance continues to
indicate that a 15-25% chance that thunderstorms could form along
the Lane and Linn County Cascade crest this afternoon and evening
due to this increased monsoonal moisture plus lift from the
shortwave. Additionally, latest runs of some CAMs indicate
isolated thunderstorms could continue through the overnight
hours for the same region, so have bumped up the thunderstorm
chances in the forecast to 15% to account for this. Main
concerns with thunderstorms are lightning, gusty winds, and
small hail.
High pressure remains over the region, though is beginning to shift
east. High temperatures will be warm though not quite as warm as
yesterday. Observations at 2 PM PDT are in the mid to upper 80s
across the Willamette Valley, which is on track to peak in the upper
80s to low 90s. Additionally, tightened pressure gradients are
producing another round of breezy north to northwest winds across
the coast, lower Columbia River, and Willamette Valley this
afternoon and evening. Expect gusts up to 25-30 mph along the coast
and 20-25 mph elsewhere into this evening.
By tonight and into Wednesday, the upper ridge continues to weaken
and shift east as troughing takes hold across the Pacific Northwest.
This will bring cooler, more stable conditions with a return to weak
onshore flow. Expect inland highs in the low 80s and coastal areas
holding in the 60s to low 70s.
This cooler pattern appears likely to persist into the holiday
weekend, with ensemble guidance in strong agreement on broad
troughing through at least Saturday. Highs in the Willamette Valley
are expected to range from the upper 70s to low 80s, which is near
to slightly above early July climatological norms. Persistent
onshore flow may also promote morning marine stratus, especially in
low lying interior areas.
By Monday of next week, ensemble guidance begins to suggest a
transition toward zonal flow, with indications of upper level
ridging re-establishing over the western US. However, ensemble
clusters begin to diverge significantly beyond Sunday, introducing
forecast uncertainty for the early part of next week. Inland
temperatures may begin to rebound, potentially returning to the
upper 80s, though confidence in the magnitude and timing of this
warming is still limited. Surface winds are expected to remain north
to northwesterly both along the coast and inland, which may help
maintain marine influence in some areas. -HEC/Hall
&&
.AVIATION...Latest satellite imagery shows a continued narrow
strip of marine stratus resulting in IFR/LIFR cigs at KONP. KAST
has cleared out as of 22z Tuesday, however the marine stratus deck
is only a few miles to the west of the terminal and will most
likely fill back in towards 00z Wednesday. Inland, VFR conditions
will continue under mostly clear skies. Isolated thunderstorms
along and east of the Cascade crest this afternoon and evening may
result in high clouds associated with convective debris, however
cigs would remain VFR for inland terminals. Diurnal winds out of
the N to NW will increase to 15-20 kt gusting to 25 kt along the
coast, and to 10-15 kt with gusts reaching 20 kt along the Lower
Columbia including KPDX this afternoon. Winds will ease tonight.
PDX AND APPROACHES...VFR conditions will continue through 18z
Wednesday under mostly clear skies. NW winds around 10-15 kt with
gusts up to 20-25 kt will continue through 04z Wednesday before
subsiding to 8-10 kt after 06z Wed. -TK/Picard
&&
.MARINE...Persistent surface high pressure offshore will result in
continued north to northwesterly winds across the waters through
the week. Breeziest conditions are expected today, with gusts up
to 25 kt through this evening most likely south of Cape
Foulweather, easing to 15-18 kt or less by tomorrow. Small Craft
Advisories remain in effect through 5 PM this afternoon north of
Cape Falcon, and through 11 PM this evening from Cape Falcon south
to Florence. Choppy seas of 7-9 ft at 7-8 seconds will continue
through today, before subsiding to 3-6 ft tomorrow through the
weekend as winds weaken. -TK/Picard
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
PZ...Small Craft Advisory until 5 PM PDT this afternoon for PZZ251-
271.
Small Craft Advisory until 11 PM PDT this evening for PZZ252-
253-272-273.
&&
$$
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Office: PDT
FXUS66 KPDT 012351
AFDPDT
Area Forecast Discussion
National Weather Service Pendleton OR
451 PM PDT Tue Jul 1 2025
Updated Aviation Discussion...
.SHORT TERM...Today through Thursday...The PacNW will be in
between the ridging to the north and the cutoff low moving across
California. The Heat Advisory continues through this evening for
the Basin, Gorge, Yakima/Kittitas Valleys, Simcoe Highlands and
north central Oregon, given the upper ridge keeping our today's
temperatures in the low 100s for these areas. The remaining
forecast area will be in the 90s, though RHs will mainly be in the
teens across the forecast area. And with the Columbia Basin and
Kittitas Valley being drier and warmer than other locations, this
will elevate critical fire conditions for those specific areas as
well heading into Wednesday. With elevated CAPE values (>500
J/Kg), PWATs of 0.80-1 inches and low lapse rates of 6.5-7.0 C/km,
we are also looking at thunderstorms this afternoon into this
evening with abundant lightning over central OR, John Day
Highlands, and John Day Basin, thanks to the upstream
intensification influenced from the cutoff low. This allows the
Red Flag Warning for Zone OR700 through the evening as well due to
abundant lightning from these storms. In addition to that, breezy
outflow winds (15-25 mph) will be induced across the Cascade Gaps
from the strong surface pressure gradients. However, there is a
30-60% probability of wind gusts exceeding to 30- 35 mph around
the Gorge and Kittitas Valley. With persistent warm temps (<90
degrees) and low RHs (<20%), Red Flag Warning has been issued for
Wednesday from 2pm to 9pm PDT for the Columbia Basin.
Thunderstorms will develop over the eastern mountains Wednesday
late morning into evening with the CAMs showing CAPE values
becoming slightly modest (500-800 J/Kg) along with decreased PWATs
(<0.75 inches). Even though the moisture level remains low, dry
lightning can be still be threatening to potential new or ongoing
fires. However, these storms should move further eastward out of
our area by tomorrow night. Breezy to windy conditions will
continue throughout the day tomorrow across the Cascade gaps from
the strengthening surface pressure gradients. The raw ensembles
suggest a 30-50% prob for gusts exceeding to 40 mph over the Gorge
and Kittitas Valley. Winds will begin decreasing later in the
evening.
Thursday morning should be relatively quiet until evening showers
arrive. Temperatures will decrease to the 70s and 80s across the
forecast area with RHs gradually recover a bit to the 20s.
However, portions of the Yakima Valley, north central OR, and
upper part of the Lower Basin may have pockets of low RHs in the
teens. But, no critical fire conditions will be anticipated at
this time. The Cascade gaps will have breezy winds at 15-25 mph
with a 30-40% prob for gusts to reach 30 mph at Kittitas Valley.
Feaster/97
&&
.LONG TERM...Friday through Tuesday...Light showers will arrive
Friday late morning into evening at the eastern mountains with
slight chances (<30%) of afternoon thunderstorms. Weak instability
(300-800 J/Kg) and low moisture level (<0.10 inches) may inhibit
the storms from becoming severe, but CG lightning could be the
main threat. Late Friday evening into night, precip activity
should be out of the area. Although the Gorge will be gusting at
25-35 mph in the afternoon, the remaining locations will have
light winds with occasional breezes. Saturday could have morning
showers over the Wallowas but, chances are low (<20%). Starting
Saturday afternoon onwards, the weather will be warm and dry with
slight breezy winds. Feaster/97
&&
.AVIATION...00Z TAFs...VFR conditions are expected to be present
for all sites through the majority of the valid period. The
notable exception will be at KRDM/KBDN through roughly 04Z due to
ongoing VCTS. Sub-VFR conditions may develop should a heavier
shower or TS track overhead; nearby observations at KS21 suggest
localized IFR conditions are occurring within the more intense
thunderstorms. Moreover, gusty and erratic winds may occur with
these cells; so far, surface observations indicate sustained
outflow of 15-30 mph with gusts of 30-45 mph.
Looking ahead to tonight, confidence is low (<30%) in elevated
showers developing over PSC/ALW/PDT/DLS, so have excluded mention
in the TAF. Otherwise, westerly winds will ramp up later
Wednesday morning and afternoon. Plunkett/86
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 66 93 58 87 / 10 20 10 0
ALW 70 93 62 86 / 10 20 10 0
PSC 67 96 59 89 / 0 10 0 0
YKM 66 94 57 87 / 0 0 0 0
HRI 69 96 60 89 / 10 10 0 0
ELN 65 88 57 82 / 0 0 0 0
RDM 56 88 46 82 / 30 10 0 0
LGD 63 90 54 84 / 10 20 20 10
GCD 60 91 52 86 / 20 20 20 10
DLS 66 86 60 83 / 0 0 0 0
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Heat Advisory until 9 PM PDT this evening for ORZ041-044-507-508-
510.
Red Flag Warning from 2 PM to 9 PM PDT Wednesday for ORZ691.
Red Flag Warning until 9 PM PDT this evening for ORZ700.
WA...Heat Advisory until 9 PM PDT this evening for WAZ024-026>029-521.
Red Flag Warning from 2 PM to 9 PM PDT Wednesday for WAZ690-691.
&&
$$
SHORT TERM...97
LONG TERM....97
AVIATION...86
