Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 09/09/22
Area Forecast Discussion
National Weather Service Charleston SC
1016 PM EDT Thu Sep 8 2022
A cold front will remain south of the area into Friday, before
likely shifting back into the area over the weekend. Another
cold front could impact the region during the early to middle
of next week.
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
A low level easterly flow off the ocean and a mid and upper
south to southwest flow out of the Gulf of Mexico will support a
continued feed of abnormally moist air, where PWat will reach at
least 2.0 to 2.25 inches across the area. The 18Z run of the GFS
depict dilatation axes setting up across much of the forecast
counties. Combined with strong forcing from the front to the
south and blocking high pressure to the north, the end result
will be for increasing convective rains through the night. Radar
estimates showed as much of 4-6 inches on Thursday across parts
of coastal Liberty and coastal McIntosh. While it is possible
that similar localized amounts can occur further north through
the overnight, 1 to 2 inch amounts will be more common from
coastal Bryan and parts of Chatham County north to parts of
Charleston County. It is definitely concerning that recent runs
of the HRRR show some 1-2 inch amounts per hour. With the
antecedent wet grounds it won`t take much to produce at least
minor flooding. Expect at least the issuance of Flood
Advisories. While some heavy rains can move into the Charleston
metro overnight, the better chances still look to stay to the
south and over the ocean.
A mid and upper level trough will pull off the east coast, as a
deep low aloft spins near the mouth of the Mississippi River
through the night. At the surface a stationary front just to the
south of the region will fluctuate north or even transform into
a warm front as it tries to lift into the southern counties
overnight. The forcing from the front and embedded short waves
aloft will combine with deep tropical-like moisture, with PWats
some 120-140% or normal, plus strong low level convergence and
better isentropic ascent, will lead to increasing coverage of
showers and t-storms through the night.
Diurnal activity has diminished a bit from earlier, and is
already starting to show signs of increasing coverage again
near the coast due to low level moisture convergence. Leaning to
a consensus of the 18Z HREF, recent runs of the HRRR and the
NBM, we show coverage to peak in at least the 50-70% range,
greatest near the coast. The best forcing initially occurs over
southeast Georgia prior to midnight, then spreads into parts of
South Carolina after midnight.
We added mention of heavy rains over some east and southeast
counties due to the HREF probabilities of at least 20-40%
chances of more than 3 inches in each 3 hour window from the
late evening through the overnight. At this time the heaviest
rains do look to stay south of Charleston through 6 AM, but
Beaufort and Savannah seem to have a much greater chance of
receiving heavy rains. On average rainfall amounts will be 1-2
inches, but as usual, locally higher amounts up to 3 or 4 inches
can occur, especially over the coastal counties south of
Temps will get down close to evening dew points, which are
mainly in the 70-75F range.
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...
Aloft, a closed low centered across the northern Gulf of Mexico and
Deep South will slowly shift north this weekend, eventually phasing
with a longwave trough tracking across the Central United States to
the Northeast by early next week. At the sfc, high pressure centered
across the Mid-Atlantic and Northeast states will gradually give way
to the approaching low/longwave trough, helping sfc low pressure
associated with the cutoff low to advance north and a front to drift
back into southern areas and/or along the coast this weekend well
ahead of a cold front advancing closer to the region early next
week. The overall pattern favors deep moisture to be drawn from the
Gulf of Mexico and Atlantic, setting up an unsettled pattern across
the Southeast through the weekend.
Friday appears the be of most concern in regards to the potential of
heavy rains and a marginal risk of severe weather across the local
area, but much will depend on the position of a front across/near
southern areas and/or near the coast in regards to stronger storms.
The mid-upper-lvl low positioned to the west is expected to draw
moisture across the front in an environment already displaying PWATs
in excess of 2.0 inches. Although showers/thunderstorms should move
along, the combination of shortwave energy rippling across the
region, moisture convergence, and favorable isentropic lift across
the local area suggests widespread showers along with a few embedded
thunderstorms capable of producing heavy rains/flooding, especially
since the front remains somewhat anchored across the area for an
extended time. Rainfall amounts in the 2-4 inch range are expected,
locally higher amounts are possible, especially across southern
areas near the coast. Flood Advisories should eventually be needed.
Further south, the risk for stronger thunderstorms is a bit higher,
but will be highly dependent on the northward progression of the
front. Modest low-lvl winds and instability wrapping around the
eastern edge of the northern tracking sfc low combined with ample
forcing associated with the front and mid-lvl shortwave energy
rippling across the region, suggest a few strong and/or marginally
severe thunderstorms near the front across southeast Georgia capable
of damaging winds in the form of wet downbursts given deep moisture
and poor low-mid lvl lapse rates. There also appears to be a small
window of time for a weaker tornado across southeast Georgia given a
backing wind component along the sfc low and 25-30 kt 0-6km bulk
shear present during highest instability (mainly mid-late afternoon
hours), but widespread rain/showers and cloud cover should limit a
tornado threat considerably and likely keep the risk south of the
local area or perhaps offshore.
Saturday and Sunday: The main concern for the remainder of the
weekend will continue to be a locally heavy rainfall threat and
potential for flooding, given a continuation of h5 shortwave energy
rippling across the Southeast United States and the vicinity of a
front. The issue could be exacerbated along the coast if rainfall
coincides with high tide (see tide section below). WPC currently
highlights most of the area in a Marginal to Slight Risk Saturday,
which could eventually be extended into Sunday. The severe weather
threat will remain low. Rainfall totals Saturday through Sunday
should average in the 1-3 inch range, highest near the immediate
coast, but isolated higher amounts are possible.
High temperatures during the weekend will average below normal with
clouds and rain around. It will be coolest on Friday when highs top
out around the upper 70s to lower 80s, but should slowly warm to the
mid 80s Saturday and Sunday. Lows will mainly be in the low to mid
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
Ridging off the Southeast coast will weaken early next week as an
expansive mid level trough and phasing closed low shifts towards the
East Coast. Meanwhile, a cold front will slowly progress into the
region Monday night into Tuesday, possibly stalling in the vicinity
mid week. Showers and thunderstorms will be possible each day, but
it doesn`t look as active/wet as the upcoming weekend. It should
return to a more typical diurnal pattern. Temperatures will largely
be within a few degrees of normal.
.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
KCHS and KJZI: Both terminals look to stay VFR the first part of
tonight, with increasing chances for flight restrictions to
occur late tonight and especially on Friday. This will occur as
a stationary front to the south begins to lift back north as a
warm front and considerable moisture and lift develop over the
area. This will cause numerous to occasional widespread
SHRA/+SHRA with scattered TSRA. We show MVFR conditions starting
around 11Z and continuing through the rest of the 00Z TAF cycle.
But IFR is certainly possible at times.
KSAV: While we begin the night with VFR conditions, it looks to
deteriorate down to MVFR by around 04Z and will stay at least
down in the MVFR range the rest of the forecast period, if not
even lower. This occurs as stationary front nearby lifts north
as a warm front. That along with considerable moisture and
lift, it will generate numerous to widespread SHRA/+SHRA and
scattered TSRA, especially overnight and Friday.
Extended Aviation Outlook: Periodic flight restrictions in showers
and thunderstorms are likely through the weekend and into early next
Tonight: The pressure gradient between a stationary front to
the nearby south and high pressure in the Northeast will cause
the gradient to become somewhat pinched over the marine area.
We certainly can`t rule out some Small Craft Advisories. But
for now we increased NE and E winds to 15-20 kt with some higher
gusts, and will continue to monitor. Seas will be a mix of wind
driven shorter periods and swell driven longer periods,
averaging 3-5 feet, with some 6 footers perhaps sneaking into
the outermost Georgia waters near 50-60 nm offshore and maybe
near 20 nm off Charleston County. Mariners should remain alert
for increasing coverage of t-storms through the night. Some of
which will be strong and will likely require the issuance of
Marine Weather Statements and/or Special Marine Warnings.
Friday through Tuesday: Onshore flow will prevail through the
weekend, then gradually veer south early next week as high pressure
to the north shifts offshore in advance of a cold front arriving
late Monday into Tuesday. The pressure gradient between the high and
low pressure tracking inland will favor a slightly enhanced gradient
across local waters and wind speeds topping out near 15-20 kt,
staying just shy of Small Craft Advisory criteria early this
weekend. Winds will then weaken, averaging 15 kt or less late
weekend into early next week. Seas will be 3-5 ft initially, then
subside to 2-4 ft. There will be potential for stronger winds and
reduced visibilities within showers and thunderstorms which should
be plentiful through at least the weekend.
Rip Currents: Long period swell around 11-12 seconds being generated
from distant Hurricane Earl combined with onshore winds will lead to
an elevated risk of rip currents at all of our beaches through the
weekend. The current forecast features a High Risk for all
beaches Friday, and a continuation of at least a Moderate Risk
along all beaches Saturday.
The combination of the upcoming full moon and onshore winds
will lead to elevated tide cycles through the weekend. Coastal
Flood Advisories will likely be needed, especially with the
evening high tides into the weekend. The risk will be highest
along the Charleston and Colleton County coasts, where minor to
moderate coastal flooding will be possible. Further south, tide
levels could approach minor flood levels. In addition,
conditions will be exacerbated if rainfall coincides with the
time of high tide.
Area Forecast Discussion
National Weather Service North Platte NE
633 PM CDT Thu Sep 8 2022
.SHORT TERM...(This evening through Friday night)
Issued at 317 PM CDT Thu Sep 8 2022
Temperatures and precipitation will continue to be the
main concern along with the remaining potential for critical fire
weather concerns through the rest of today into the early evening.
See fire weather discussion below for more details.
Temperatures the remainder of the afternoon will continue to rise
for areas across the southern Sandhills, central and southwest
Nebraska as the Katabatic cold front pushes through there will be
compressional heating which will result in a brief sharp
temperature rise where highs could exceed over 100 degrees, which
has already been seen across the northern Sandhills this
afternoon. Valentine went from 100 to 106 degrees within a half
hour as the front passed through, then temperatures begin to fall
shortly after the passage.
As for precipitation chances this evening into the overnight, did
decrease chances, this evening, as there is a lot of dry air that
should inhibit much precip. However, if a thunderstorm does develop,
there is a potential for dry lightning as any thunderstorm that does
develop will likely be LP in nature. Most models have some chances
of precip overnight, although the HRRR has been trending much
drier, did keep slight chances in the forecast through the
overnight. Precip chances will mainly be across the Sandhills into
north central Nebraska, confidence is low in precipitation across
southwest Nebraska so kept PoPs out of the forecast during the
For Friday, precipitation chances increase in the evening hours as
an increase in low level moisture will move into the region ahead of
an upper level trof. Highs on Friday will be 30 to 40 degrees
cooler than today with temperatures only in the mid 60s to low
.LONG TERM...(Saturday through Thursday)
Issued at 317 PM CDT Thu Sep 8 2022
Precipitation chances continue on Saturday as the upper
level trof continues to push through the Nebraska. Main mode of
precipitation will generally be rain showers, as instability will
be lacking, so there is low confidence in any thunderstorm
activity. Highs on Saturday will only be in the 60s. Temperatures
Saturday night will be considerably cooler with lows dipping into
the upper 30s across the western Sandhills. The upper level ridge
begins to build in the beginning of next week, thus the cooler
temperatures will be short lived and warmer temperatures return.
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 633 PM CDT Thu Sep 8 2022
For the 00z TAF cycle. A cold front currently bisects western
Nebraska from southwest to northeast. The front has passed through
KVTN and more recently, KTIF. Timing on the front through KLBF is
around 00z this evening. An abrupt wind shift to the north will
occur with the frontal passage, additionally, CB and the
occasional cloud to cloud lightning strike will be possible, but
coverage does not warrant a mention in the official TAF for KLBF.
It should be noted that there is a substantial dry layer below
any CB, if a TS were to form, expect very gusty erratic wind, but
on limited visby disruptions. Otherwise MVFR ceiling invade
western Nebraska by 15z tomorrow with the threat of showers. Lower
ceilings at KLBF should occur just beyond the forecast cycle.
Issued at 317 PM CDT Thu Sep 8 2022
A strong cold front will push through the area later this
afternoon into the evening hours. Winds will shift abruptly to
the north with passage of the front and gusts up to 30 KTS will be
possible. The front is expected to pass through the KVTN terminal
this afternoon and early this evening at the KLBF terminal. Skies
will be scattered at 25000 FT AGL through daybreak Friday.
Ceilings will lower to 3000 to 6000 FT AGL Friday morning.
Red Flag Warning until 8 PM CDT this evening for NEZ204-206-
Area Forecast Discussion
National Weather Service New Orleans LA
643 PM CDT Thu Sep 8 2022
(This evening through Saturday)
Issued at 337 PM CDT Thu Sep 8 2022
Starting out in the upper levels, a broad ridge centered near the 4-
Corners region extends from California to beyond the Great Lakes. A
trough sagging southeast over the Appalachian Mountains stretches
southwest to the north-central Gulf of Mexico. The base of this
trough is virtually right over the CWA. As the next few days
progress, the base of the trough will be clipped off and become a
cutoff low. In fact, recent satellite shows the mid-level
circulation already starting up.
One of the main things that the presence of the upper low will do
maintain higher rain chances. Looking closely at the water vapor
imagery, there`s pockets of drier air mixed in and rotating the low.
Recent upper air soundings show modest moisture available in the
column and ample CAPE. It suggests a reflectivity output that the
latest HRRR shows for this afternoon is fairly likely. Afternoon
convective initiation has already begun with fairly decent coverage
already north of I-10/12 corridors. Intensities aren`t particularly
strong as of 20Z but still seeing an uptick periodically. Main
concern will be gusty winds and small hail. Per latest sounding,
instability is quite high with MUCAPE over 2500J/KG and LI`s up to -
7. Shear is virtually non-existent.
Friday and Saturday will be quite similar as the overall pattern
shows little change. The upper low will be completely closed off at
this point and meandering around south Louisiana. It should be
deeper at this point, which will both likely support higher rain
chances but also keep temps down below normal (the 2nd effect of its
local presence). There`s a low chance for some localized flash
flooding as training will be possible but the threat doesn`t appear
to be particularly high at this point.
(Sunday through Wednesday night)
Issued at 337 PM CDT Thu Sep 8 2022
Moving into the latter half of the weekend, an upper level trough
will be dropping out of the High Plains down into the mid
Mississippi Valley. At the same time, the upper low that`s been
sitting over the local area will be weakening while being absorbed by
this approaching upper trough. A cold front associated with the
trough will be moving south across TX, LA, and MS. Some showers and
storms are expected to develop ahead of this boundary and impact the
local area. Coverage looks to be less than previous days as PW`s
aren`t quite as high. Additionally, instability doesn`t look overly
impressive but sufficient for thunderstorms.
The first few days of next week will start off with scattered to
numerous showers and storms as the boundary reaches the CWA. Models
suggest the upper trough will close off a low near the Great Lakes
and it will slowly progress eastward. That puts the CWA right on the
southern extent of the trough`s influence...pretty close to zonal
flow. Thus, the boundary will probably stall somewhere within the
CWA. This will create a gradient of low POP`s to the north higher
POPs to the south as well as cooler temps to the north and warm to
the south. Expect to see larger swings in POPs and Temp forecast for
that timeframe as models attempt to resolve the movement of a weak
Issued at 643 PM CDT Thu Sep 8 2022
Expect all of the terminals to be VFR throughout the night. The
convection that occurred during the day today has mostly died out
with the exception of a cluster of storms in southern Terrebonne
Parish. MCB did not have any fog or low ceilings this morning, so
because of that along with low guidance confidence, VFR conditions
are forecasted to prevail there. Later in the period, high
resolution model guidance suggests more widespread convection than
today, so VCTS was introduced at all terminals around 18-19z. The
same guidance suggests that the convection will move from east to
west and be widespread over the whole area with the exception of the
far western portions. So, all terminals have TEMPO groups for
thunderstorms in the afternoon timeframe except BTR. (Zeringue)
Issued at 337 PM CDT Thu Sep 8 2022
Increasing daily thunderstorms will continue to be the main impact
for tidal lakes and nearshore waters over the next few days. Broad
scale winds and seas will remain in light with 5 to 10 knots and
seas of 2 feet or less due to such a weak surface pressure field in
place. The main concern from any thunderstorms will be brief periods
of gusty winds up to around gale, frequent lightning, and the
potential for a few waterspouts.
.PRELIMINARY POINT TEMPS/POPS...
MCB 66 84 67 84 / 20 80 30 70
BTR 69 88 70 88 / 40 70 20 70
ASD 70 88 70 89 / 60 80 40 60
MSY 74 86 74 87 / 60 80 40 60
GPT 71 86 71 88 / 50 80 50 50
PQL 70 85 71 88 / 50 80 60 50
Area Forecast Discussion
National Weather Service Miami FL
815 PM EDT Thu Sep 8 2022
Issued at 738 PM EDT Thu Sep 8 2022
Radar data shows a large cluster of showers with embedded
thunderstorms moving eastward across Collier and Hendry counties,
while lingering rain can be observed across much of the Atlantic
The cluster over west SoFlo is connected to a larger line that
stretches from the SE GOMEX through Central Florida, and seems to
have enough energy to at least bring showers across our central
areas and along interstate 75 for the next hour or so. And with
potential for more showers following up, POPs/Wx grids have been
updated to keep scattered to numerous coverage over much of west
SoFlo through 04Z. Convection should decrease after midnight, with
southerly synoptic flow becoming light.
Overnight lows will be similar to the past few days with values in
the low-mid 70s inland, and upper 70s to around 80 near the coast.
(Rest of today through Friday)
Issued at 310 PM EDT Thu Sep 8 2022
South Florida remains nestled between an upper level low centered
just offshore of the Florida panhandle, and upper level ridging
extending poleward from the Bahamas poleward the western Atlantic
waters. This upper low will slowly drift eastward and approach the
west coast of Florida. This will allow for a slight augmentation
of shear and moisture profiles across the region, which will favor
the development of discrete and semi-organized thunderstorms this
afternoon. VAD wind sampling and HRRR forecast soundings have
hinted at a mild low-level veering of winds, which should allow
for increased moisture transport. Overall, today`s environment
will be favorable for scattered to numerous showers and
thunderstorms across the region. PW may reach or exceed values of
2.2 inches this afternoon, which coincides with the overall storm
coverage and marginal excessive rainfall outlook via the Weather
Prediction Center. Cloud-layer mean winds out of the
west/southwest around 5-10 kt should allow for storms to gradually
drift towards the ENE with time; however localized flooding and
ponding of roadways will be the main threat to monitor for today.
Other associated impacts include strong (likely sub-sever) wind
gusts, and frequent lightning strikes.
By tomorrow, an H250 jet streak will progress through the mean
synoptic flow, and allow for the aforementioned upper trough/low to
become negatively tilted. This will present a setup that features a
modest shear enhancement in the 0-3km range, which may allow for a
few semi-discrete thunderstorms to end the week. Additionally, deep
southwesterly flow remains intact, which will continue to maintain
deep moisture across South Florida (PW around 2.0 to 2.2 inches).
Overall, this environment may allow for an isolated low-end severe
thunderstorm to materialize across portions of the southern
peninsula; however localized flooding and ponding of roadways
remains the main hazard to monitor for tomorrow.
Hot and humid conditions remain in place across South Florida.
Afternoon maxes will generally reach the lower 90s, while some
locations may approach record maximum temperatures in the mid 90s.
Interior locations may experience heat indices in excess of 105
degrees today and tomorrow afternoon.
(Friday night through next Wednesday)
Issued at 310 PM EDT Thu Sep 8 2022
This Weekend: Over the weekend, the cut off low will begin to
break down with pressure from the large trough in central
continental US. Unsettled weather will continue with south-
southwesterly flow on Saturday bringing plentiful moisture to
South Florida. On Sunday, as the cut off low begins to break down
with the amplification of the upper level trough, a shift to
southerly flow will ensure no end to showers and thunderstorms.
The primary concern with the weekend`s activity will be localized
flooding due to the slow-motion, high PWATs of these storms.
Caution needs to be used when on roads, especially if in urban
areas, during the activity.
Monday - Wednesday: Moving into next week and typical South Florida
wet season, there is no indication of any end to instability and
moisture allowing for continued unsettled weather. With the sea
breezes and afternoon convection, there will be daily potential for
lightning, brief gusty winds, heavy downpours, and localized
flooding. The mid-level flow and surface winds will begin to
shift bringing a change to the convection pattern, but no break
High temperatures will continue to remain near normal. However, with
the humidity, we will not be getting a break from the triple digit
heat indices anytime soon. Lows will be in the 70s with near 80
along the Atlantic Coast.
Issued at 743 PM EDT Thu Sep 8 2022
Brief bouts of sub-VFR conditions could still be possible at the
start of the TAF period as lingering convection gradually
diminishes. Overnight, a return to light/variable winds and
generally VFR conditions. Tomorrow, continued SW flow and moisture
transport could lead to scattered to numerous SHRA/TSRA for all
terminals, with MVFR/IFR conditions and short-fuse TEMPOs all
possible. Winds along East Coast terminals will see a shift to
more SSE flow as sea breeze develops in the late morning/early
Issued at 310 PM EDT Thu Sep 8 2022
A wet and unsettled pattern will develop to round off the week, as
an upper disturbance increases storm activity across the local
waters. This should allow for scattered to numerous shower and
thunderstorm activity, with the greatest overall coverage being
realized over the Gulf waters. Aside from convective related
impacts, seas should remain relatively flat (no greater than 2 ft);
however by this weekend, a northeasterly swell may be observed owing
to downstream effects of Hurricane Earl. This may result in higher
waves for portions of the Atlantic waters.
Issued at 310 PM EDT Thu Sep 8 2022
Increasing Atlantic swell will result in an elevated risk of rip
currents for the Palm Beaches for today, while a high risk for rip
current will likely develop for coastal Palm Beach tomorrow and
through the weekend.
.PRELIMINARY POINT TEMPS/POPS...
Miami 79 92 81 92 / 50 60 20 50
West Kendall 76 92 77 93 / 40 60 20 50
Opa-Locka 78 92 79 93 / 50 60 20 60
Homestead 77 91 78 91 / 40 50 30 50
Fort Lauderdale 80 92 81 92 / 50 60 20 60
N Ft Lauderdale 80 91 81 92 / 60 70 20 60
Pembroke Pines 78 92 79 92 / 50 60 20 60
West Palm Beach 77 93 78 92 / 50 70 20 60
Boca Raton 78 94 80 93 / 60 70 20 60
Naples 78 89 78 91 / 70 80 50 70
Area Forecast Discussion
National Weather Service Medford OR
855 PM PDT Thu Sep 8 2022
.DISCUSSION...No further updates are needed this evening. With
offshore flow picking up in earnest today in SW Oregon as the
thermal trough set up along the coast, NE winds channeling down
the Chetco River Valley led to a high of 96F at Brookings this
afternoon. It is still 88F there as of 8 pm! With NE winds
continuing there overnight into Friday, temperatures won`t cool as
much as they usually do at night and this will likely allow it to
get hot again on Friday. It could also get quite warm Friday north
of Cape Blanco and nearly all the way to the beaches -- that
will depend on how strong the east winds are. It could get to the
upper 80s around Coos Bay. Oh, and it is ridiculously dry out
there. Humidity along the south coast this afternoon was off the
charts dry, less than 10%. Of course, it`s already been dry over
inland areas, but this should give you a good idea of what`s
coming for inland areas tomorrow and Saturday -- more hot and dry!
There is enough of a temperature gradient between sea and land to
form a full-fledged thermal low pressure system, which will move
northward along the coast Friday and eventually out over the
ocean. This will send the thermal trough inland and lead to a wind
reversal along the coast. More marine influence will end the heat
wave at the coast Saturday. But it will get nasty hot again
inland with more records likely falling. This is a bit dependent
upon how much wildfire smoke is out there from existing fires.
But, we have a high of 103F forecast for here in Medford Friday
(record is 103F set in 1944) and 105F for Saturday (record is 104F
set in 1922). These are some very old records potentially falling
folks! For obvious reasons, everyone should remain vigilant about
the extreme fire danger over the region. The conditions the next
2 days are extremely conducive to rapid fire spread, so be extra
careful not to cause new ignitions. Prevent wildfires. One less
spark, one less wildfire!
We do expect a change toward cooler weather by next week, so
that`s good, but rain chances are still a bit up in the air.
Please see previous discussion below for more details on the Red
Flag Warnings, Heat Advisories and Air Quality Alerts that are in
.AVIATION...09/00Z TAFs...Conditions will remain VFR through Friday
afternoon, except for reduced visibility in the vicinity of
wildfires. The highest probability of reduced visibility will be in
northern Klamath County and far eastern Douglas County with smoke
arriving from the Cedar Creek Fire in eastern Lane County. New fires
southeast of Klamath Falls and in the Warners of Modoc County are
also producing smoke that is affecting visibility. -Sven/DW
.MARINE...Updated 800 PM PDT Thursday 08 September, 2022...A strong
thermal trough will persist along the coast into Friday. The strong
north winds and steep to very steep seas are beginning to weaken,
but will persist into Friday night. Winds shift to southerly Friday
night as the coastal low moves far offshore. This will result in a
southerly surge of low clouds and fog, initially near shore, that
will spread across the waters. Southerly winds near to above
advisory strength and a short period northwest swell will produce
steep seas Saturday. Conditions then improve early next week as the
low weakens. -DW
.PREV DISCUSSION... /Issued 429 PM PDT Thu Sep 8 2022/
UPDATE...Temperatures have risen to 96F at Brookings this
afternoon with strong northeast winds funneling down the Chetco
River Valley, a bona fide Brookings effect. With the expectation
that these winds will continue overnight through at least early
afternoon Friday, we have expanded the heat advisory to include
the Curry Coast. Temperatures probably won`t cool off that much
tonight, at least to what would typically occur, except at the
immediate beaches. We are expecting lows in the 60s to near 70F.
And, temperatures will once again have the opportunity to rise
into the mid to upper 90s on Friday before some marine air brings
temperatures back closer to normal Friday night into Saturday.
PREV DISCUSSION... /Issued 252 PM PDT Thu Sep 8 2022/
SYNOPSIS...A plethora of critical fire conditions are expected
Friday into Saturday with a thermal trough bringing another round
of hot, very dry, windy, and unstable conditions to the area. Hot
temperatures will generate moderate heat risk for locations west
of the Cascades Friday and Saturday. Early next week, a couple of
low pressure troughs will move through Pacific Northwest and could
produce periods of showers and storms depending on monsoonal
moisture transport and the transport of moisture from Hurricane
* FIRE WEATHER: Hot, dry, windy, and unstable conditions will
result in several periods of critical fire weather concerns this
afternoon through Saturday. This includes most of our area`s
new fires. Avoid using any equipment that can cause sparks and
be sure to follow all fire restrictions.
* HEAT: Increased risk of heat related illnesses for most of the
West Side this weekend. Stay hydrated with water, take frequent
breaks in air conditioning, and check in on neighbors and
friends without AC. Additionally, some medications may make you
more prone to heat illnesses, talk to your doctor/pharmacist for
* SMOKE/WILDFIRES: Smoke from area wildfires will continue to
impact air quality for many areas. Of note, smoke and air
quality levels will fluctuate and depend on just how much smoke
is output from these fires, the wind directions/speeds and also
A thermal trough has been keeping the temperatures in Brookings
on the warm side for the last 24 hours. They`ve seen temperatures
around the mid 80`s as of 5 am this morning and highs pushing
into the mid 90`s as of this afternoon. The Chetco effect is also
creating critical fire weather conditions along the southern
Oregon coast and that is discussed in the fire weather discussion
Otherwise, smoke from the Cedar Creek fire is heading south and
will continue to impact the Klamath Basin this evening with
moderate to unhealthy air quality. The HRRR smoke model does show
a southerly smoke trajectory in the latest model runs. With east
flow developing later tonight, many areas west of the Cascades
will begin to see smoke concentrations increase. An Air Quality
Advisory has been issued by the Oregon Department of Environmental
Quality due to higher smoke concentrations spreading out across
the region. The Cedar Creek Fire will likely remain the biggest
contributor given it`s current size on satellite. Other recent
fires may contribute more smoke to the region as fire weather
conditions deteriorate into Saturday.
Temperatures will challenge record highs in Medford, Mount Shasta
City and Klamath Falls Friday and Saturday. It`s not set if we
will indeed break temperature records, but we will at least come
close. Thermal troughs moving back inland have a habit of being a
bit warmer than the models anticipate.
By late Saturday, an upper level low and surface low out over the
Pacific will begin to change the overall wind flow over the area.
A more southerly component to the winds will emerge at most levels
of the atmosphere. By Sunday, temperatures will indeed trend lower
for almost all locations except for some areas within Lake County.
Coastal stratus will likely cover large sections of the coast as
the thermal trough retreats farther inland Sunday into Monday.
Thunderstorms are the main none smoke concern heading into next
week as tropical moisture and energy from hurricane Kay makes it`s
way all the way into northern California and Oregon. Right now,
the probability of thunder remains low as ensembles are not quite
convinced of rain showers or thunderstorms east of the Cascades
AVIATION...08/18Z TAFs...Conditions will remain VFR through
the next 24 hours, except for reduced visibility in the vicinity of
wildfires. The highest probability of reduced visibility will be in
Klamath County and into northeast Siskiyou and northwest Modoc
counties, with smoke arriving on a northerly flow from the Cedar
Creek Fire in eastern Lane County. New fires southeast of Klamath
Falls and in the Warners of Modoc county are also producing smoke
that is affecting visibility. -Sven
MARINE...Updated 200 PM PDT Thursday 08 September, 2022...A strong
thermal trough will persist along the coast into Friday. Strong
north winds and steep to very steep seas will reach peak strength
this afternoon and evening. Conditions begin to improve Friday as
the thermal trough briefly moves inland. The thermal trough will
weaken and a closed surface low will move offshore Friday night into
Saturday with a southerly surge of low clouds and fog initially near
shore that will spread across the waters. Meantime, areas of steep
seas will likely linger into Saturday. Conditions continue to
improve early next week as the offshore low weakens and moves
FIRE WEATHER...Updated 200 PM PDT Thursday 08 September 2022...
Gusty winds and low relative humidities, and gusty winds with
moderate to poor overnight recoveries, especially over the mid
slopes and ridges will be the main concern into Friday evening for
the coastal mountains, northwest fire zone 280, and all of fire
zone 618, and Saturday evening for the Cascades, Siskiyous and
An upper trough will swing northeast of our area into western
Montana tonight, this has resulted in gusty east to northeast winds
blowing near and at the ridges along with extreme dry conditions.
These winds are occurring on a lesser scale right now. For example
right at the coast, Brookings is now 93 degrees with a relative
humidity of 7 percent! Red Mound is 86 degrees, with relative
humidity of 8 percent and northwest wind at 14 mph with gust to 35
mph! The latest info on the fuel status for fire zone 618 is that
fuels are extremely dry and receptive.
Breezy north to northeast winds and dry humidities are likely for
portions of the West Side today, especially funneling into the
Illinois Valley and portions of Western Siskiyou County. This will
bring forth critical fire weather conditions for these areas into
this evening. Tonight, moderate to poor overnight recoveries are
expected with gusty east to north east winds and Friday will be
similar to this afternoon with gusty winds and low relative
humidity. In addition high Haines of 6 is expected for the Rum Creek
Fire Friday. Because of the above mentioned reasoning, the Red Flag
Warning was adjusted and will be in effect until Friday evening.
As this trough exits the area tonight, expect winds to become
easterly once again tonight into Saturday evening across the
Southern Oregon Cascades as well as the foothills, Umpqua Divide,
Siskiyous. Along the upper slopes and ridge tops in these locations
expect poor recoveries and breezy winds. Valleys and more sheltered
areas may see more moderate to locally poor recoveries. It is worth
noting that area wildfires west of the Cascades will not benefit
from the Marine Push the next couple of days.
The other problematic portion of the forecast comes in with the
hot, dry, windy, and unstable conditions in the forecast beginning
Friday and Saturday. These conditions will be present across all
of our existing and new fires giving rise to the potential for rapid
spread through plume domination. Conditions on Saturday could be
similar to Friday, and an additional red flag warning will likely be
needed for Saturday for the Rum Creek Fire. For other fires, like
the Twelve Mile Creek Fire in Douglas County, NAM and GFS soundings
are indicating a Haines of 5 for these days, but it would not take
much to jump it into a Haines 6. Will headline the haines 5-6
conditions in the Fire Weather Planning Forecast, noting that Haines
6 may be present in the forecast, without a Red Flag Warning.
Beginning on Sunday monsoonal moisture and moisture from a weakening
tropical system will start to feed into the area. Confidence is low
in the details of the forecast, as the ensembles have lessened the
moisture feed into our area from the tropical system, keeping
thunderstorm chances mainly for the East Side aligned with monsoonal
moisture. We will continue to update this as the forecast confidence
OR...Red Flag Warning until 9 PM PDT Friday for ORZ618>620.
Heat Advisory from 11 AM Friday to 11 PM PDT Saturday for ORZ024-
Heat Advisory until 8 PM PDT Friday for ORZ022.
Red Flag Warning from midnight tonight to 10 AM PDT Saturday for
Heat Advisory from 11 AM Friday to 11 PM PDT Saturday for ORZ023.
CA...Red Flag Warning until 9 PM PDT Friday for CAZ280.
Heat Advisory from 11 AM Friday to 11 PM PDT Saturday for
Pacific Coastal Waters... Small Craft Advisory from 2 AM Friday to 2 AM PDT Saturday for
Hazardous Seas Warning until 2 AM PDT Saturday for PZZ350-356-
Gale Warning until 2 AM PDT Friday for PZZ356-376.
Area Forecast Discussion
National Weather Service Pocatello ID
159 PM MDT Thu Sep 8 2022
.SHORT TERM...Tonight through Friday night.
Strong cold front has moved into Wyoming with gusty winds expected
to continue through about sunset before dissipating rapidly
overnight. Have widespread wind gusts over 30 mph through about 9
pm occasionally reaching 40 mph. Outside of the winds main short
term impact is the much cooler temperatures today behind the cold
front with about 10 to 15 degrees of cooling from yesterday and
another 5 to 10 degree cooler high temperatures day on Friday. Many
highs on Friday will stay in the 60s high elevations and 70s low
elevations. As flow turns more northwesterly expect areas of smoke
and haze overnight into Friday.
.LONG TERM...Saturday through Thursday. Upper ridge builds back
into the region behind departing trough. Temperatures start to
rebound above normal, but remaining well below recent hot stretch.
Focus turns to moisture from Hurricane Kay remnants sliding north
through the Great Basin. There is good ensemble and cluster
agreement in pushing the ridge axis east by Tuesday. Showers and
thunderstorms look to return to East Idaho as early as Monday
afternoon. Precipitation chances remain low until later Tuesday as
next Pacific trough shifts inland, and the NBM really starts
ramping up precipitation chances beginning Tuesday afternoon. It
is still to early to hang a hat on any potential precipitation
amounts, but precipitable water values from deterministic GFS look
to be 0.75->1.0" which certainly holds hope. Best chances for
beneficial rainfall appears to be Tuesday night through Thursday.
.AVIATION...Winds and pockets of thunderstorm activity remain the
concerns for today. Line of thunderstorms working east through the
northeast corner of the region this afternoon; will continue with
VCTS at DIJ, though line may skirt just to the north. Gusty winds
continue through the Snake Plain, with the highest values over
the Arco Desert. Terminals should max out with gusts around 30kts.
Blowing dust may be a localized concern. Dry cold front sags
south through East Idaho this evening, turning winds to the north
and decreasing speeds 00z-04z. Unfortunately, this has the added
complexity of smoke inundation to the surface overnight per HRRR
Near-Surface Smoke fields. Held off on significant visibility
restrictions for terminals, but MVFR reductions with localized or
brief IFR visibility are certainly possible. The smoke is likely
to continue into Friday. DMH
The cold front which moved through the district it into Wyoming and
strong winds have developed behind it. A Red Flag Warning remains
in effect until 9 pm for winds gusts exceeding 30 mph with the
northerly direction in zones 475 and 476 of concern for the Moose
fire. Humidity should also drop rapidly after 3 pm as it has
remained over 15 percent for most of day as of 1 pm. Winds will die
down rapidly overnight and expect minimal wind impact on Friday.
Generally a north to northwesterly directions most zones in the 5 to
15 mph range. May see some gusts approaching 20 to 25 mph in the
afternoon but will not be widespread. Upper ridge rebuilds over
Idaho over the weekend with well above normal temperatures
returning. There is the potential for much wetter conditions with
rain next week.
.AIR QUALITY...Wildfire smoke remains the underlying concern for
air quality across the region. Gusty winds continue today, but
winds diminish overnight with high pressure returning to the
region beginning Friday. Return to overnight inversions should
continue to trap existing and new smoke at the surface through at
least Saturday. DMH
Red Flag Warning until 9 PM MDT this evening for IDZ410-411-413-
Wind Advisory until 9 PM MDT this evening for IDZ052-053.
Lake Wind Advisory until 9 PM MDT this evening for IDZ054.
Area Forecast Discussion...UPDATED
National Weather Service Portland OR
903 PM PDT Thu Sep 8 2022
Updated aviation and marine discussion
.SYNOPSIS...A strong east wind event is on tap for the Friday into
early Saturday timeframe. This will bring critical fire weather
conditions, above normal temperatures, and smoke and haze in various
quantities for different parts of the area. A southerly flow reversal
late Sunday into Monday will lead to a strong onshore push which will
replenish moisture for lower elevations to start the work week.
.SHORT TERM...Through Saturday...
(1) Strong east winds are expected for the Cascades, Cascade
Foothills, and Coast Range - especially along exposed ridges and in
terrain gaps (most notably the Columbia River Gorge).
(2) Widespread haze is likely from fires east of the Cascades.
(3) Smoke is expected in the south Willamette Valley (mainly Lane
Co.) from the Cedar Creek Fire burning near Waldo Lake. Smoke is
possible elsewhere in the Willamette Valley.
(4) Much above normal temperatures will be present where there isn`t
smoke on Saturday.
It`s a challenging forecast on this Thursday afternoon, with low
confidence in the outcome of several related forecast variables.
First off, a highly anomalous wind event is expected beginning as
early as mid-morning Friday morning as cold air settles east of the
Cascades to drive a 16mb to 19mb North Bend to Spokane surface
pressure difference. The Extreme Forecast Index (EFI) continues to
highlight large areas of values greater than 0.95 along the Cascades,
with embedded values greater than 0.99 indicating the event is nearly
outside of the 20-year model climate for wind speed. Forecast
soundings from the NAM continue to suggest sustained wind speeds of
around 50 kt in the roughly 2-5kft layer, while the GFS and RAP
remain weaker. The gradient alone, however, would suggest the NAM is
closer to reality, and hence gust potential, should efficient mixing
of these winds to the surface manifest, will be at least within the
50-55mph range. Forecast soundings continue to suggest that it will
be difficult to mix these winds to the surface most everywhere, which
is good news. Unfortunately, however, exposed ridges in the Cascades
and Coast Range will be within the layer of strongest winds, and the
channeling effect of the Columbia River Gorge will force more intense
near-surface winds there than elsewhere. Thus, these locations will
be favored for intense winds which will likely peak only a little bit
shy of their max intensity during the Labor Day 2020 east wind event.
Friday afternoon through early Saturday morning is looking to be the
period of strongest winds for those areas of greatest concern.
Given the strong east winds, there are concerns for smoke advection
from both the Cedar Creek Fire (mainly for the south Willamette
Valley) and other fires in eastern Oregon and eastern Washington. The
HRRR smoke output continues to suggest that copious quantities of
smoke will impact Lane County through Saturday, while further north
across the remainder of the area skies will be hazy with perhaps some
settling of low level smoke that gets trapped beneath the inversion
overnight Friday night and Saturday night. The best pathway for low
level smoke to enter the northern Willamette Valley and adjacent
south Washington will be the Columbia River Gorge, through which
strong winds could advect quite a bit of smoke from eastern Oregon -
though it must be stressed that confidence in this scenario is low at
this time. One thing for which confidence is high: wherever thick
smoke accumulates in the lower atmosphere, temperatures will be
significantly less hot on Saturday than expected, as smoke
particulates inhibit incoming shortwave radiation`s ability to reach
Speaking of temperatures, uncertainty in the quantity and location of
smoke continues to lead to uncertainty in the temperature forecast
for particular locations. NBM continues to suggest a 50% probability
that temperatures will reach the triple digits in Eugene on Saturday,
but if dense smoke impacts the area then one of the lower probability
model outcomes will likely materialize and temperatures might not
escape the 80s. Farther north where smoke is less likely to have a
substantial impact on temperatures, NBM probabilistic information is
likely more useful. In Salem, the model blend gives a 25th percentile
temperature forecast of 97 - meaning that there is a 3 out of 4 (or
75%) chance that temperatures will be 97 or hotter. From a
thermodynamic perspective, it`s a complex conceptual forecast, as
cooler air east of the Cascades is what`s driving the downsloping,
but air that descends mountains is warmed dry adiabatically by
compression...so do temperatures wind up warmer or cooler than
expected? For now, we`ll continue to hedge with the NBM, all the
while warning folks for the possibility that smoke significantly
drives down high temperatures near and downwind (i.e., west and
southwest) of the Cedar Creek Fire. -Bumgardner
.LONG TERM...Saturday night through Wednesday...The thermal low
breaks off Saturday morning, and subsequently moves northward just
offshore through Sunday morning, driving a southerly flow reversal
which should bring an onshore push - first in the south Valley and
later for the rest of the interior - overnight Saturday night. This
should replenish moisture levels somewhat for low elevation locations
for the start of next work week. Sunday night into Monday, there will
even be a chance for drizzle along the coast as the marine layer
deepens with the approach of an upper trough which the bulk of the
ensemble thinks will pass just to our northwest.
Further out in the extended period, cluster analysis suggests little
uncertainty in the overall upper pattern with a slow approaching
trough from the west and the ridge gradually becoming less amplified
and shifting eastward through the work week. Both the EPS and GEFS
have many members that suggest precipitation at PDX by late week,
indicating needed precipitation - beyond just a few AM sprinkles -
could finally arrive for much of the area. In addition, the ensemble
is cooler next week overall; NBM suggests the 10th to 90th percentile
maximum temperature range at PDX spans 73 to 82 for both Tuesday and
Wednesday, which would put us close to our average high of 78
.FIRE...Expect a quick transition to offshore flow to commence this
evening as high pressure builds overhead and another disturbance
dives out of western Canada into the upper trough over ID/MT. East-
northeast winds will begin to increase by late evening over the OR
Casacdes, contributing to poor overnight recoveries as RH values
only climb into the 30s overnight. Still thinking inversions will
keep winds out of the inland valleys until Friday morning, but winds
will then quickly expand westward to the coast during the day on
Friday as the surface pressure gradient tightens in response to
strengthening low pressure along the coast and high pressure in the
Columbia River Basin. Red Flag warnings thus remain on track with
respect to timing and forecast details. Expect winds to peak Friday
night into early Saturday with some gusts to 50 mph over exposed
terrain in the Cascades, with 40-45 mph gusts in the Columbia River
Gorge favored terrain in the Coast Range. Expecting gusts around 35
mph in the Willamette Valley, but can`t rule out a few gusts
approaching 40 mph. This will coincide with minimum RH values in the
teens across most of the area, with poor overnight recoveries,
especially in the higher terrain.
Winds should diminish relatively quickly on Saturday night as
another trough approaches offshore and the gradient weakens. This
will yield improving although still relatively dry conditions for
Sunday, with onshore flow pointing to more seasonable temperatures
and less dry conditions going into next week. Finally, there is
still a hint that the remnants of a tropical storm will approach the
area early next week, with a resulting slight chance of
thunderstorms sometime early next week. Confidence in this scenario
remains low at this time. /CB
.AVIATION...06Z TAFs: The broad area of low pressure over Canada
coupled with building high pressure offshore will maintain dry
flow aloft across the Pacific NW through the TAF period. East
winds will ramp up Friday and peak during the overnight hours
Friday into Saturday. A backdoor front, or one that approaches
from the northeast, will swing towards the Pacific NW Friday
evening. Building high pressure behind the front will pack that
cooler air into the low levels and accelerate wind speeds across
most of the CWA. Wind gusts at many Willamette Valley terminals
will see wind gusts up to 35 kt. The Coast Range will block the
east winds slightly but coastal terminals may see elevated east
winds gusting to 20-25 kt. The greatest impacts will be across the
Cascade crest where wind gusts up to 50 kt are likely as well as
along the western slopes into the foothills where downsloping
winds could reach similar magnitude.
This forecast is making the assumption that no significant fires
are in the area to cause reduced visibility at terminals.
However, spreading of current fires east of the Cascades and fire
starts overnight will reduce visibility from increased smoke.
For detailed Pac NW aviation weather information, go online to:
KPDX AND APPROACHES...VFR conditions will persist throughout the
forecast period. Expect north winds to shift to easterly by 18Z
Friday. Gusts up to 40 kt possible. -BMuhlestein
.MARINE...High pressure remains over the waters through Friday
along with a thermally induced low pressure along the southern
Oregon coast. This will maintain northerly winds across the
coastal waters through Friday afternoon. Winds will begin to shift
offshore Friday evening and an exceptionally strong gradient for
this time of year will setup overnight Friday into Saturday.
The thermal low over the OR/CA border then drifts offshore early
Saturday. This will setup another round of offshore winds across
the waters as it`s pulled west, winds will shift southerly by
Sunday that will become more southerly on Sunday and are expected
to persist through the middle of the upcoming week.
A northwesterly swell coupled with a northwest windsea will
produce steep and choppy conditions across the waters through
Friday afternoon. Seas around 8 to 11 feet with a dominant period
of 7 to 9 seconds are expected through tonight. East winds
through the Coast Range gaps will make for chaotic seas. Seas then
gradually subside over the weekend to around 4 to 6 feet.
Stronger tidal currents are occurring ahead of the full moon on
Saturday. Strong ebb currents during the overnight hours will make
for hazardous conditions. Those moving in and out of harbors and
crossing coastal bars should use caution and be aware of any bar
restrictions in place. -BMuhlestein
For information about upcoming marine zone changes, go online to:
OR...Red Flag Warning from 11 AM Friday to 8 PM PDT Saturday for
Central Oregon Coast-North Oregon Coast.
Red Flag Warning from 11 AM Friday to 11 PM PDT Saturday for
East Slopes of the Central Oregon Coast Range-North Oregon
Coast Range-Willamette Valley.
Red Flag Warning until 11 PM PDT Saturday for Central Oregon
Cascade Foothills-Mt. Hood National Forest West of Cascade
Crest-North Oregon Cascade Foothills-Willamette National
WA...Red Flag Warning from 11 AM Friday to 8 PM PDT Saturday for
South Washington Coast and West Willapa Hills.
Red Flag Warning from 11 AM Friday to 11 PM PDT Saturday for
Clark County Lowlands-East Willapa Hills-Eastern Gifford
Pinchot National Forest Mt Adams Ranger District-Extreme
South Washington Cascades and Foothills.
PZ...Small Craft Advisory from 2 AM to 6 AM PDT Friday for Columbia
Small Craft Advisory until 11 PM PDT Friday for coastal waters
from Cape Shoalwater WA to Florence OR out 10 nm.
Small Craft Advisory until 2 PM PDT Saturday for Waters from
Cape Shoalwater WA to Cascade Head OR from 10 to 60 nm.
Small Craft Advisory until 9 AM PDT Saturday for Waters from
Cascade Head to Florence OR from 10 to 60 nm.
Interact with us via social media:
Area Forecast Discussion
National Weather Service Reno NV
156 PM PDT Thu Sep 8 2022
Temperatures will continue to gradually drop into the weekend, but
will still remain above average. Isolated to scattered showers and
thunderstorms will impact the eastern Sierra this evening and on
Friday. Much cooler temperatures along with precipitation will
then enter the area by Sunday through at least next Tuesday.
.SHORT TERM...This Afternoon through Friday...
It looks like we`re continuing our streak of very hot, near-record
temperatures for the western NV valleys and Lake Tahoe area. If we
havn`t set enough records already this September, we`ll come very
close to either tying or setting a new daily record high again today
in Reno. Temperatures throughout the region will cool a bit on
Friday, making records less attainable. However, high temperatures
will remain up to 10 degrees above average for mid-September.
For this evening and as well as on Friday, the CAMs show enough
surface instability to allow for some showers and thunderstorms to
form over Alpine, Mono, and Mineral counties. Much like the last
few days, DCAPES suggest the biggest threat from these storms
will be strong outflow winds gusts up to 50 mph. The risk of
flooding remains low due to limited/elevated moisture.
The one thing I didn`t miss at all that has unfortunately returned
is the wildfire smoke. Several area wildfires have already caused
unhealthy air quality in South Lake Tahoe and Carson Valley.
Latest HRRR smoke model output indicates smoke and poor air
quality will continue to impact much of the central Sierra and
western NV tonight through tomorrow. For the latest air quality in
your location, visit www.airnow.gov -McKellar
.LONG TERM...Saturday through next Thursday...
Plan on cooler and potentially wetter conditions for Sunday into
the beginning of the work week as extensive remnant tropical
moisture surges into the Sierra and western Nevada. While
hurricane Kay is projected to be well off the southern CA coast,
the deep southerly flow will kick up precipitable water values
across the region with many locations nearing the 1 inch mark.
Widespread cloud cover may limit the potential for thunderstorms
on Sunday, but any clearing may allow for some embedded convection
to fire off. The question marks in the forecast involve the
incoming trough off the West coast and how that will interact with
the remnant hurricane and tropical moisture. Depending on where
the shortwaves sweep through the region there could be a decent
line of convective potential, but those details may be difficult
to dial in until the higher resolution models are available. For
now it appears the better potential for meaningful wetting rains
will arrive with the trough on Monday or Tuesday, rather than with
the initial moisture push over the weekend.
While the precipitation forecast holds some uncertainty, we can say
with relatively high confidence that the temperatures will be on the
cool, more typical side of the spectrum.
*Haze & Smoke - Smoke and haze from several wildfires burning in
central and northern California will impact slantwise
visibilities throughout much of western NV and the Sierra. MVFR
visibilities in smoke and haze are possible at all terminals
except for KMMH through at least Friday.
*Storms - For this evening and on Friday, there is a 15-25% chance
of showers and thunderstorms over mainly Alpine, Mono, and
Mineral counties, primarily impacting KMMH. Storms will be
capable of producing outflow wind gusts in excess of 40 kts.