Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 09/02/22
Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
820 PM CDT Thu Sep 1 2022
.UPDATE...
Issued at 818 PM CDT Thu Sep 1 2022
A pre-frontal trof and extreme heat helped kick off a few
thunderstorms this evening. But, with the loss of diabatic
heating, the storms are quickly dying. As the main front moves in
late tnt, a few more showers and storms appear possible, and that
activity remains evident in the latest runs of the HRRR model.
Temperatures overall look fine.
&&
.SHORT TERM...(This Evening through Friday Night)
Issued at 322 PM CDT Thu Sep 1 2022
The main challenge in the short term is fire weather on Friday.
For tonight into Friday morning, a number of the latest CAMs develop
a few showers and perhaps a weak storm (HREF mean MUCAPE of ~500
J/kg) across northeastern SD and west central MN tonight into Friday
morning, in response to an incoming cold front. However, this
activity will be interacting with dry air, so maintained less than
20% PoPs through this time. The cold front will track across the CWA
from northwest to southeast through the morning. Due to a good surge
of CAA, northerly winds within the first couple post-frontal hours
may gust in excess of 35-40 mph. Thereafter, winds will lessen,
but should remain somewhat breezy through the afternoon (20-25
mph gusts) due to good mixing with very dry air in place during
peak heating. Blended in the HREF to get lower dewpoints Friday as
well, which led to minimum RH values in the upper teens to mid
20s across central SD. Opted against a fire weather headline at
this time, as the strongest winds are offset from the lowest RH in
terms of timing. Recent rains have made for non-critical fuels
across portions of central SD as well. High pressure builds in
Friday evening, leading to lessening winds, clear skies and
relatively cool overnight lows in the upper 40s to low 50s.
.LONG TERM...(Saturday through Thursday)
Issued at 322 PM CDT Thu Sep 1 2022
Upper ridging will dominate the pattern over the holiday weekend and
into the upcoming work week. Most days will see highs well above
normal for early September, in the upper 80s to mid 90s Monday
through Thursday. The main forecast challenges will be the
temperatures, which could exceed guidance during the day and then
fall below guidance in the dry air overnight, and fire weather west
river. The lack of precipitation over the next week plus the very
warm max Ts will lead to quick drying of fuels. Winds will be the
deciding factor a few days this week as to fire weather concerns.
Sunday and Monday appear to be the days to watch for the moment with
a passing dry front and breezy southerly winds.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday Evening)
Issued at 613 PM CDT Thu Sep 1 2022
Terminals KABR,KATY,KPIR,KMBG
VFR skies/vsbys are expected through tonight, along with isolated
showers/storms. Winds will turn gusty behind a front overnight.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&
$$
UPDATE...TDK
SHORT TERM...Lueck
LONG TERM...Wise
AVIATION...TDK
Area Forecast Discussion
National Weather Service Columbia SC
1035 PM EDT Thu Sep 1 2022
.SYNOPSIS...
Moisture and precip chances build back across the region Friday
as southeast flow increases. This moist and somewhat unstable
airmass will then stay in place through the weekend and last
into next week.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
Upper level low over southern Georgia this evening. Showers and
thunderstorms have diminished but at 02z radar showing a few
showers re-developing in the SC coastal plain moving northwest
toward the southeast Midlands and CSRA. These showers are
associated with east low-level moisture flux...resulting high
precipitable water 1.8 to near 2 inches and some lift
associated with short wave trough rotating northwest from the
upper low. Raised pops again to chance in that region. The
model consensus focus scattered light showers/maybe a
thunderstorm given some weak instability mainly in the
southeast Midlands and CSRA through the overnight. Cloud cover
should limit radiational cooling especially in the southeastern
counties with lows ranging from the upper 60s north to lower 70s
southeast.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
Similar setup to today will exist again on Friday, with maybe a bit
more moisture. Mid level trough will be pushing into southeastern
Canada, and with strong subsidence on the backside of that, will
help to strengthen a surface high to our north. As this pushes off
the New England coast, expect onshore flow to increase across the
region, helping to increase PWs, especially across the southwestern
FA. Additionally, the weak shortwave present across southern GA
today will be nearer to the CSRA tomorrow. With PWs rising to near
2", expecting scattered to numerous showers to develop again
tomorrow afternoon. Much like today, there should be a sharp cutoff
between who sees rain and who doesn`t, with that cutoff likely
splitting the Midlands. I am fairly confident that the western
Midlands and CSRA will see showers/storms, but am not as confident
from Columbia and points north and eastward. Highs will likely be
near normal, with upper 80s likely everywhere. It`ll probably be
warmer in the northeast where sunny skies are more likely to
dominate. Overnight lows will end up in the low 70s. I expect some
showers to hang on Friday night as well with the weak shortwave
finally traversing through the region and to the east.
Saturday looks more wet, with higher PWs overspreading the area. MOS
Guidance is indicating PoPs in the 45-60% range across the area.
We`ll be within good onshore flow across the region, with
southeasterly flow noted up to 850 hPa. As a result, ECM and GFS are
indicating PWs exceeding 2" across much of the area by Saturday
afternoon. Though the shortwave from Thursday and Friday will have
pushed east, expectation is that inverted surface troughs along the
southwestern side of the surface high will be plenty to force
afternoon showers/storms within a moisture rich environment. As a
result, going with high end Chance to low end Likely PoPs (50-60%)
across much of the area. This will likely keep afternoon temps a tad
below normal, with highs in the mid and upper 80s expected. Showers
should be slow to diminish on Saturday night, but I expect that they
will at some point during the overnight period. Lows will likely end
up in the low 70s.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
Sunday and Monday look like wet weather days again, with scattered
to numerous showers and storms possible both days. Setup will remain
fairly similar, with guidance maintaining high PWs across the area
near and above 2". With weak mid-level troughing approaching from
the west, showers and storms are likely to develop across the region
both afternoons. Models differ on what happens with this troughing
towards mid week, but trends are towards weak troughing remaining
across the OH Valley and southern US through the end of the period.
If this is correct, we`ll be stuck between the ridge to our south
and the trough to our west, with high PWs remaining over us. This
will lead to wet weather through at least the middle of next week,
with at least isolated to scattered showers/storms expected each
day. This seems to be the direction the models are going, and is
represented in the forecast. Daily highs should be near to slightly
below normal, with lows in the upper 60s and low 70s.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
Combination of nearly stationary upper energy and low level
moisture flux convergence providing SHRA activity moving NE that
appears will affect OGB/AGS/DNL in the near term. CIGs have
fallen to MVFR at AGS/DNL at 02z. Latest SREF and HRRR trending
more pessimistic with stratus coverage tonight. Will indicate
IFR restrictions at all sites.
Little overall change in the pattern Friday. Best moisture to favor
AGS/DNL area, so will restrict afternoon VCTS mention to those
sites.
EXTENDED AVIATION...Chance of mainly afternoon thunderstorms, and
late night/early morning fog/stratus.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
&&
$$
Area Forecast Discussion
National Weather Service Dodge City KS
614 PM CDT Thu Sep 1 2022
...Updated Aviation Discussion...
.SHORT TERM...(This evening through Friday)
Issued at 345 PM CDT Thu Sep 1 2022
The mid-afternoon water vapor loop and RAP analysis showed an
elongated shortwave trough extending from northern KS, through
southwest KS and south into the TX Panhandle. The best deep layer
forcing for ascent was moving into south central KS and adjacent
northwest/north central OK, which is where several clusters of
thunderstorm activity were found. This included the Red Hills region
of southern Comanche County where radar indicated a quick inch or
more of rain...generally south and east of Coldwater.
As the mentioned shortwave trough continues to move across the
Central Plains through the evening, deeper layer subsidence will
overspread southwest Kansas, and additional thunderstorm activity is
most likely not expected, as a result, across our forecast area.
On the heels of this afternoon`s wave will be another upstream wave
moving south-southeast through the larger scale pattern. A polar
front will be accompanying this next wave, which will become the
primary focus for loosely organized thunderstorm activity, first
developing across far northwest KS into southwest Nebraska. The 6-8
km AGL winds will be out of the north 30 to 45 knots, which will aid
in increasing deep layer shear to support organized multicell
structures if not marginal supercell structures at times. That being
said, low level moisture will be decreasing the farther west one
goes into western Kansas, thus the primary risk from the strongest
storms would most likely be in the form of damaging wind gusts. Most
of the convective-allowing models (CAMs) show somewhat organized
convection moving south across much of southwest Kansas through the
late evening hours, hence the increase in POPs to 30 to 40 percent
over a larger portion of our forecast area.
On Saturday, the front will clear the southwest Kansas region with
slightly cooler temperatures in the afternoon on northeast winds.
Renewed thunderstorm activity late Saturday and Saturday Night would
be confined to areas south of southwest Kansas into the West
Texas/Texas Panhandle/northwest Oklahoma region.
.LONG TERM...(Friday night through Thursday)
Issued at 345 PM CDT Thu Sep 1 2022
The theme of dry and warmer than normal will continue through next
week as the dominant upper level high will persist across the West,
and this will keep western Kansas in a northeasterly upper level
wind pattern. Additional shortwave troughs will round the upper
ridge and move south/southeast across mainly the eastern Great
Plains, and this is where the focus for rain and thunderstorm
activity will most likely be early next week. The southwest Kansas
forecast will be dry from Saturday Night through early next week.
A deeper polar jet stream trough will likely develop across the
Pacific Northwest region toward the end of the forecast period. There
is also some indication from global deterministic models, as well as
ensemble systems like GEFS and EPS, that a tropical system of some
fashion may move north through the Gulf of California/Baja
California which may also aid in breaking down the persistent upper
level high out West. This is 6+ days away, though, so there remains
tremendous uncertainty regarding how fast/significant the upper high
out west will really break down, leading to a change in our sensible
weather out here across southwest Kansas.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 602 PM CDT Thu Sep 1 2022
Scattered ceilings with cloud bases as low as 4000 to 6000ft AGL
will be possible from 00z and 03z Friday as few isolated
thunderstorms dissipate between Dodge City and Hays. The winds
overnight will be south southeast at 10 knots or less. Towards
daybreak these light winds along with some increasing near
surface moisture may result in patchy early morning fog and/or
low stratus at 1000ft or less based on the latest BUFR soundings
and HREF visibility forecast. The area with the highest
probability for this to occur will be near and east of the Dodge
City area. After 14z what fog that does develop will give way to
VFR conditions as south winds at 10 knots or less continues.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 66 96 62 91 / 10 10 30 10
GCK 64 96 60 89 / 0 10 30 10
EHA 63 96 61 90 / 0 10 20 10
LBL 64 96 62 91 / 10 10 20 10
HYS 66 96 61 88 / 10 20 30 0
P28 68 96 65 92 / 10 10 30 20
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Umscheid
LONG TERM...Umscheid
AVIATION...Burgert
Area Forecast Discussion
National Weather Service Goodland KS
547 PM MDT Thu Sep 1 2022
.SHORT TERM...(This evening through Sunday)
Issued at 215 PM MDT Thu Sep 1 2022
Upper ridge centered over the Great Basin will be controlling
feature for the short term period. Main concerns will be on
Friday, as a cold front trailing from a northern plains low will
initiate scattered thunderstorms as it moves through the area.
The hot and dry environment will once again favor wind and blowing
dust as the primary hazards, although there may be just enough
instability and shear to support a more organized updraft capable
of producing marginally severe hail. There are some timing
differences among the CAMs. The HRRR is the fastest of the models,
with most of the convection south of the area by 00z, while
NAMnest has storms lingering through about 03z. Hard to discount
either solution at this time, so will smooth out the POPs to try
to account for the differences. In addition to the thunderstorms,
fire weather will be a concern, mainly in western and northern
parts of the area. Northeast winds will increase behind the front
with occasional gusts to 25 kts possible. Relative humidity will
drop to the 15-20% range as well. Coordinating with surrounding
offices, will message near critical conditions and not issue any
highlights, though it will be close. High temperatures will be in
the upper 90s and lows Friday night in the 50s.
The weekend will be quiet with no precipitation expected.
Temperatures will be slightly cooler on Saturday behind the front
with highs in the upper 80s, rebounding to the lower 90s by Sunday
as the ridge nudges eastward. Low temperatures will be in the 50s.
Keeping an eye on fire weather, humidity will be too high on
Saturday for any concerns, but does drop to near 20 percent on
Sunday with light winds, suggesting the possibility of elevated
conditions if the dew points can mix out a bit more.
.LONG TERM...(Monday through Thursday)
Issued at 1254 PM MDT Thu Sep 1 2022
Next week continues to look warm and relatively dry across the area.
There could be a chance for storms around the mid part of the week
but there is uncertainty as to whether or not moisture will move
into the area and where the better forcing will be in the Plains.
The upper level pattern continues to be forecasted with a ridge
across the Western CONUS, tilting towards the Great Lakes Region.
Meanwhile, the cut-off low from the trough over the Eastern CONUS is
still forecasted to be confined to near Texas before moving off to
the northeast later in the week. This will keep the area dry and
warm to start the week with more northerly flow aloft over the area
and a lack of disturbances moving through. Monday and Tuesday are
forecasted to see highs in the upper 80`s and 90`s under mostly
clear skies. Lows should drop to near or just below 60.
Around Wed-Thur, there is a small chance for storms as the upper
pattern changes with the shift in the cut-off low. However, guidance
differs on how the pattern will evolve. Some suggest that the ridge
will amplify over the Central CONUS while others suggest a small
disturbance will move through from the northwest. Ensemble guidance
isn`t too optimistic about a disturbance moving in from the
northwest until outside the forecast period, but the feature could
be small enough to be muted in the ensembles. The other factor will
be the availability of moisture. Compared to yesterday, guidance has
backed off and shifted the moisture surge from the south further
east away from the area except for the GFS. If moisture doesn`t
advect in from the south, storm development would be unlikely short
of maybe an isolated storm or two in the afternoons. Given the
ensemble pattern and most guidance leaning dry, that is the current
forecast with sunny conditions and highs in the 90`s. However, if a
disturbance moves through and/or moisture advects in from the south,
conditions would instead be cloudier and cooler with increased
chances for storms. If a disturbance does move through with the
moisture fully advecting in from the south, there could even be
severe storms or heavy rain totals. Will have to watch as this
scenario is currently unlikely based on model trends and the
suggested upper pattern.
Another thing to watch is the potential for near-critical to
critical fire weather conditions if the drier and warm conditions
prevail. However, the surface pattern without a disturbance would
likely be benign with a broader pressure gradient across the area
leading to relatively light winds around 15 mph or less which would
inhibit critical fire weather conditions.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 540 PM MDT Thu Sep 1 2022
VFR conditions will prevail at MCK and GLD through the 00Z TAF
period. Mostly clear skies will become partly cloudy after 22Z
Friday afternoon with light south winds increasing and becoming
gusty as they turn to the northeast.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...024
LONG TERM...KAK
AVIATION...LOCKHART
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
902 PM CDT Thu Sep 1 2022
.UPDATE...
Issued at 902 PM CDT Thu Sep 1 2022
No major changes to the going forecast with only minor tweaks to
temp and sky trends. Am still thinking that sprinkle/isolated
shower chances are pretty low across northwest parts of the
forecast area overnight toward daybreak. The trajectory of the
shortwave trough moving NE across south-central IA keeps it to
the northwest. Satellite shows an expansion of mid level cloud
cover eastward from the wave in the presence of increasing mid
level warm advection. 00z DVN sounding shows steep mid level lapse
rates which will spread northeast along the IL/WI border
overnight with the warm advection. A fair amount of dry air
remains below the mid cloud base which, combined with the deeper
forcing associated with the wave remaining to the west, suggests
that it would be pretty tough to get any kind of showers to
develop this far east. Still cannot rule out some sprinkles from
the warm advection with the favored area being along and west of
I-39 and perhaps along and north of I-90 a bit to the east of
I-39.
MDB
&&
.SHORT TERM...
Issued at 218 PM CDT Thu Sep 1 2022
Through Friday...
Main items of note:
* Small chance for an isolated shower overnight far NW CWA
* Very warm and breezy on Friday
While September marks the start of meteorological fall,
Friday`s weather (like today`s/Thursday`s) is a reminder that
there`s still a few weeks left of astronomical summer. Forecast
highs on Friday are a degree or two warmer than this afternoon`s
temps. Increasing high clouds have been spilling eastward as a
slow moving and moisture starved short-wave treks slowly east-
northeast toward the MS River.
With modest but persistent south-southwest winds and increased
cloud cover tonight, expect milder overnight low temperatures
ranging from the mid and upper 60s outside Chicago to low 70s in
the city. Most forecast soundings appear too prohibitive for any
precip into far north central and northwest Illinois in the pre-
dawn hours of Friday. However, a few models are close with a
couple hour of near mid-level saturation (around 9-10kft AGL)
that could tap into a corridor of steep mid-level lapse rates for
spotty high based showers. Given the steep lapse rates, there`s a
non-zero chance for a rogue thunderstorm. With most guidance
leaning dry, kept PoPs non-mentionable in the northwest, but may
need to entertain at least sprinkles mention if observed sounding
data suggests sufficient moisture for spotty showers.
Friday should see a gradual scattering of the mid and high clouds
with south-southwesterly flow strong enough to keep lake breeze
development at bay, with possible minor exception of a slight
south-southeast bend to the wind along the far north shore. Expect
gusts up to 20 mph or so, with potential for a few hours toward
mid day of gusts up to 25-30 mph from a departing modest low-level
jet. With the warmer start to the day and progged 925 mb temps
again in the low-mid 20s Celsius, forecast highs are in the upper
80s for many locations and up to 90-91F in the heart of the
Chicago urban heat island away from the lake (explicit range of
85-91F). Dew points in the low-mid 60s will mean a slightly humid
feel to the already well above normal temps, appropriate heading
into the start of the unofficial last weekend of summer.
Castro
&&
.LONG TERM...
Issued at 314 PM CDT Thu Sep 1 2022
Friday Night through Thursday...
Our weekend kicks off with a quiet Friday night. Over the past
couple of days, guidance has been indecisive on whether or not a few
isolated showers would be reeled in from the northwest Friday
evening and night as they form along an approaching cold front.
While it looks likely that showers and perhaps a storm or two will
be forming not far to our northwest, our profile simply looks far
too dry above 850mb to maintain any showers activity in the CWA and
a serious lack of forcing certainly won`t help. The HRRR is perhaps
the most aggressive with the rain chances as it has a weak little
MCV develop over eastern Iowa Friday evening underneath a supposed
buckle in the low level flow. If this solution comes to fruition,
then I suppose it`s a possibility that a few light showers could
survive long enough to fall on the far northwest CWA, but this is a
big outlier. Therefore, slight chances were removed from the
forecast to show dry conditions area-wide.
Better rain chances arrive on Saturday as the front passes through
the area. This boundary is anything but impressive appearing very
shallow with gradual forcing. With an 850 mb trough moving over the
area, low level lapse rates could get pretty steep by midday.
There`s a lot of uncertainty among guidance on how much instability
will build up ahead of the front and how low the LFC will drop. The
NAM is the most aggressive with as many as 2,500 joules of MUCAPE
and an LFC near 900 mb. However, even with a favorable thermodynamic
environment, this solution still only supports shallow, short-lived
pop-up thunderstorms seeing as the mid-levels on either side of the
front remain notably dry and we have, quite literally, no forcing
aloft. With such weak flow above the surface, it won`t take long for
any showers or thunderstorms to drown themselves out. That is,
however, if we can get parcels lifted to their LFC. This also means
that any precipitation should hug the front pretty closely with no
pre- or post-frontal precip expected. Overall, I don`t expect
anything more than a brief period of afternoon showers and
thunderstorms, but also wouldn`t be surprised if the area remains
dry. Saturday will also be another hot day with continued southerly
flow ahead of the front and ample sunshine helping to pull
temperatures back into the middle and upper 80`s.
Following frontal passage, winds readily shift to NNE and pick up in
magnitude as an encroaching High centered up in Ontario tightens up
the surface pressure gradient. This will result some sizable waves
and hazardous swimming conditions in Lake Michigan beginning
Saturday evening and lasting through much of Sunday. These winds
will also result in some cooler conditions on Sunday with areas
roughly north of I-88 forecast to top out in the middle and upper
70`s. Sunday afternoon, a broad area of low pressure is expected to
throw up a swath of showers and light thunderstorms across central
and southern IL. Some guidance likes the idea that some of this rain
will make it as far north as the southern CWA and into parts of
northwest Indiana. Forecast soundings looked reasonably supportive
of this so some rain and thunder chances were kept in the forecast
for areas roughly along and east of I-57.
Conditions then look, for the most part, dry and warm through the
first half of the upcoming workweek. A quiet synoptic pattern sets
up following the weekend with fairly steady mid and upper level
heights and the jet seated well up to our north. However, guidance
is all over the place with mesoscale features next week throwing up
everything from low level shortwave perturbations to small vort
maxes to weak, albeit notable, low level jets. A lack of moisture in
the mid-levels should inhibit most shower development. However, a
couple of convective afternoon showers or light thunderstorms could
be possible when you consider we have no prominent high pressure
system or synoptic-scale subsidence and there`s potential for some
good diurnally-driven instability to build up. All in all though, it
looks like the vast majority of next week, at least through
Thursday, will be quiet and rain-free. Temperatures will be rather
consistent through the week with highs in the lower and middle 80`s,
perhaps a bit warmer come Thursday with some surface warm air
advection slated to take place along with steady height rises aloft.
Doom
&&
.AVIATION...
For the 00Z TAFs...
626 PM...No forecast concerns this period. Southwest winds will
diminish under 10kts with sunset this evening and turn more
southerly. South/southwest wind directions are expected Friday
with speeds increasing back into the 10-12kt range and gusts into
the 15-20kt range possible. Winds will diminish under 10kts with
sunset Friday evening. There is a small chance for a few sprinkles
or a few light showers across northwest IL tonight. cms
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...None.
&&
$$
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Area Forecast Discussion
National Weather Service Spokane WA
342 PM PDT Thu Sep 1 2022
.SYNOPSIS...
Temperatures have eased a little today before another warmup on
tomorrow with more triple-digit heat possible. Slightly cooler
temperatures will arrive by the weekend accompanied by breezy
winds, elevated fire concerns, and isolated dry thunderstorm
chances. Next weeks highs will trend down to closer to season
normals.
&&
.DISCUSSION...
Thursday afternoon thru Saturday:
Today features a 4-9 degree reduction in high temperatures
compared to yesterday, but temperatures remain 10-15 degrees above
average. This corresponds to high temperatures in the low to mid
90s. GOES-18 CIRA Geocolor imagery reveals a large area of smoke
east of the Cascades that will likely stick around as winds are
light. The smoke source is from multiple regional and local
wildfires. AirNow and PurpleAir sensors have indicated moderate to
unhealthy air quality regionwide through the early afternoon, with
the worst AQ in the Methow Valley, Wenatchee area, eastern WA, and
the northern ID Panhandle. Light winds likely will not disperse
the smoke greatly today. Fire activity is likely to pick up Friday
and Saturday as winds pick up ahead of the incoming shortwave.
HRRR near sfc/integrated smoke depicts increased smoke activity
from fires in the Cascades, ID Panhandle, and NE OR staying in our
region through the weekend. A heat advisory has been issued for
the Columbia Basin, Palouse, Spokane/CdA area, and the Camas
Prairie Friday as temperatures will be in the mid 90s to low 100s.
There are two weather situations to keep an eye on Friday/Saturday:
1.) Fire concerns:
PWATs are set to rapidly decrease through the day Thursday as the
ridge builds. NAEFS mean PWATs are indicating they could reach as
low as 0.25 inches lee of the Cascades Friday. Relative to `79 to
`09 CSFR climatology, those are in the 2.5 to 0.5 percentiles
range. These values make sense given the current water vapor
imagery looking extremely dry in N CA. Relative humidities are not
going to recover greatly tonight (30 to 45% in the higher terrain)
given the low PWATs and will certainly reach RFW criteria Friday
(widespread 7 to 15%). RFWs have been issued for the Columbia
Basin/Palouse/Spokane/ID Panhandle Friday/Saturday given how hot,
dry, and unstable it will be Friday and Saturday.
2.) Gusty dry thunderstorms:
As the shortwave approaches Saturday afternoon, guidance is
hinting at a scenario where moderate elevated instability builds
in north Central Oregon Saturday afternoon thanks to a surge in
monsoonal moisture. The shortwave forcing looks strong and could
initiate thunderstorms that move from NE OR into the Palouse/Camas
Prairie/Spokane area Saturday afternoon. Confidence is increasing
in this solution as 12Z GEFS ensemble probability of the trough
axis being in central OR by Saturday morning is around 90% (which
is higher than the 00Z GEFS around 70%). Cannot rule out dry
thunder and gusty winds given the dry subcloud layer. /Butler
Sunday thru Thursday:
Sunday starts with a longwave trof axis oriented north/south over
the Gulf of Alaska with a longwave ridge downstream with general
axis placement over the Dakotas up into Saskatchewan that
translates east some Sunday afternoon. The resulting southwest
flow remains void of significant forcing however ensembles suggest
a weak moisture feed may have enough southerly orientation to it
to allow some upper level moisture to stream up into Eastern
Washington and North Idaho Sunday night into part of Monday. It is
not accompanied by much forcing so it may just manifest itself as
a dry cold front of sorts and bring about a slight increase in
wind gusts Sunday afternoon but with lower intensity in comparison
to Saturday`s expected wind gusts. Monday afternoon into Tuesday
the southwest flow remains with ensembles suggesting no
significant disturbances or moisture moving through it so a
gradual warming trend remains with a benign forecast of generally
clear/sunny skies. Ensembles follow this up with a trof passage
Wednesday which is slow to clear and leaves a cool northwest flow
on the back edge lingering over the forecast area for Thursday.
This allows for a cooling trend starting after Tuesday that may
bring temperatures down to near normal or even slightly below
normal on Thursday. Smoke from local and regional fires may remain
a concern however the prolonged interval of southwest flow aloft
should push most of the lofted smoke from regional wildfires to
the northeast. /Pelatti
&&
.AVIATION...
00z TAFs: VFR conditions are expected for the next 24 hours.
Winds will generally be light and diurnally driven as ridging sets
in. Smoke from regional and local wildfires may cause haze at
terminals, but no significant visibility reductions are expected.
/Butler
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 58 98 60 86 56 87 / 0 0 0 0 0 0
Coeur d`Alene 56 98 58 86 54 86 / 0 0 0 0 10 0
Pullman 55 98 54 83 50 85 / 0 0 0 20 20 0
Lewiston 63 104 65 91 60 93 / 0 0 0 20 20 0
Colville 51 97 51 89 47 87 / 0 0 0 0 0 0
Sandpoint 52 94 54 84 51 83 / 0 0 0 0 20 0
Kellogg 63 96 62 84 58 84 / 0 0 0 0 20 0
Moses Lake 57 103 60 89 53 90 / 0 0 0 10 0 0
Wenatchee 66 100 67 87 60 90 / 0 0 0 0 0 0
Omak 61 101 64 94 58 90 / 0 0 0 0 0 0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Red Flag Warning from noon Friday to 9 PM PDT Saturday for
Northern and Central Idaho Panhandle (Zone 101).
Heat Advisory from noon to 8 PM PDT Friday for Coeur d`Alene
Area-Idaho Palouse-Lewis and Southern Nez Perce Counties-
Lewiston Area.
WA...Red Flag Warning from noon Friday to 9 PM PDT Saturday for
Eastern Columbia Basin -Palouse -Spokane Area (Zone 708)-
Foothills of Northeast Washington (Zone 701)-Selkirk
Mountains of Northeast Washington (Zone 700)-Waterville
Plateau (Zone 706)-Western Columbia Basin (Zone 707).
Heat Advisory from noon to 8 PM PDT Friday for Moses Lake Area-
Spokane Area-Upper Columbia Basin-Washington Palouse.
&&
$$
Area Forecast Discussion
National Weather Service Norman OK
1059 PM CDT Thu Sep 1 2022
...New AVIATION...
.SHORT TERM...
(This evening through Friday)
Issued at 233 PM CDT Thu Sep 1 2022
Much of the CWA has received at least a wetting rain today as an MCV
pivots slowly east-northeastward along the I-44 corridor. The MCV
has had a well-defined stratiform shield around its northern and
eastern flanks on radar today, with an area of moderate rain on the
western side. This precip shield will continue to move eastward this
afternoon, bringing with it steady to moderate rainfall. Amounts
should not exceed 1/2 inch within this regime.
The MCV has complicated our convective forecast today, as extensive
cloud cover has socked in most of the CWA. Northern and western
Oklahoma have received more sunshine, and convection has developed
in those regions where destabilization has occurred. Do not
anticipate convective redevelopment to be too robust across areas
that have received extensive cloud cover and rain this afternoon.
However, prior to nighttime storms could continue to impact northern
Oklahoma where instability is greatest, and with sunshine poking
through in western Oklahoma and north Texas, storm development this
afternoon is possible there as well. Afternoon storms will contain
the potential for flooding and gusty winds, given the persistent
tropical airmass.
Overnight, the MCV/trough axis will meander eastward until it`s
centered over Tulsa. Recent HRRR guidance suggests robust, back-
building convective development along I-44 between OKC and Tulsa.
The training nature of this convection would be aided by a
convectively-enhanced 25 kt southwesterly LLJ. Uncertain whether or
not this convection will occur, and if it will remain in our CWA.
However, if this scenario occurred the potential for flash flooding
would be strong. Bumped low temperatures up a couple of degrees area-
wide tonight, because current dewpoints on the Oklahoma Mesonet
network exceed NBM low temperature guidance by up to 5 degrees in
spots and no significant dry advection is expected. Will
The MCV will wander a little further northeast into tomorrow.
However, most HREF members still develop showers and storms along
and south of I-40 during the afternoon. Will maintain mentions of
rainfall in the grids, as the past several days have shown that it
doesn`t take much large-scale support to achieve convection
initiation in this airmass. Highs tomorrow will recover to near
normal.
MEISTER
&&
.LONG TERM...
(Friday night through next Wednesday)
Issued at 233 PM CDT Thu Sep 1 2022
Monitoring tomorrow evening for the potential for a cluster of
storms to move southward out of Kansas and into northwest Oklahoma.
Depending on how late in the evening these storms arrived, they
might be marginally severe. Most CAMs diminish this activity not
long after dark. A northerly speed max will pass just to the west of
our forecast area on Saturday. This may provide the impetus for
another round of storms across the central and southern parts of the
forecast area Saturday afternoon. Flooding and water-laden
downbursts will remain the likeliest threat with any diurnal
activity on Saturday.
Following that, global models suggest that a cutoff low will develop
and meander across the southern Plains late in the weekend and early
into next week. It`s quite possible that this will lead to a repeat
of this week`s pattern - enhanced storm chances for much of the area
as it passes by to the southwest, and then storm chances across the
southern part of the CWA as it settles into Southwest Texas, and
then enhanced rain chances whenever it meanders back in our
direction. For now, will maintain chances of thunderstorms across
southern and eastern counties where the best moisture is likeliest
to be.
MEISTER
&&
.AVIATION...
(06Z TAFS)
Issued at 1056 PM CDT Thu Sep 1 2022
A few lingering storms continue southward over southern Oklahoma.
Additional convection may develop over central Oklahoma overnight
(mainly east of KOKC / KOUN). Stratus is expected to develop over
central Oklahoma, resulting MVFR (possibly IFR) ceilings late
tonight toward morning. With the recent rains and light winds,
fog development on the western edge of the stratus deck will be
possible (as well as patchy fog elsewhere). Clouds should clear
out gradually west to east.
Day
&&
.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK 81 70 90 70 / 100 50 20 20
Hobart OK 83 71 94 70 / 80 40 20 20
Wichita Falls TX 87 72 92 72 / 50 10 30 20
Gage OK 89 67 95 66 / 20 20 0 20
Ponca City OK 92 69 92 68 / 40 10 10 20
Durant OK 86 72 87 71 / 90 30 50 30
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...None.
TX...None.
&&
$$
SHORT TERM...04
LONG TERM....04
AVIATION...14
Area Forecast Discussion
National Weather Service Pocatello ID
141 PM MDT Thu Sep 1 2022
.SHORT TERM...Tonight through Friday night.
Ridge of high pressure remains centered over the central Great Basin
this afternoon. A weak shortwave trough is moving eastward over the
top of the ridge. This trough may produce slightly cooler temps for
this afternoon and Friday. In fact, the odds of seeing temperatures
in the upper 90s are below 10%. Could nearly justify canceling the
heat advisory, but with the ridge is expected to amplify over the
weekend and the temps on Friday are still near records so will
continue the heat advisory. The trough is also producing some breezy
conditions this afternoon, winds appear to be holding below advisory
levels. Winds look less for Friday as the trough moves into the
central U.S. Dry weather will persist through the short term with
any convection associated with the trough this afternoon expected to
remain east of Idaho. Smoke and haze is the final concern in the
short term. Behind this trough, winds will switch to the west-
northwest and the HRRR smoke model is showing smoke and haze from
fires across the central Idaho mountains moving into east Idaho
tonight and persisting into Friday.
Valle
.LONG TERM...Saturday through Thursday.
Models show ridge centered over the central Great Basin extending
with the axis extending northward through east Idaho on Saturday.
With the ridge strengthening, our highs will be climbing and the NBM
4.0 supporting a 75% chance of temps greater than 95 degrees across
the Snake Plain and eastern Magic Valley. Meanwhile, an area of low
pressure will be moving northward along the west side of the ridge
through Oregon and Washington. This low will move through the Idaho
Panhandle and through western Montana by Sunday morning. This will
bring another round of breezy conditions to the region for Saturday
and possibly Sunday as well. The track of the low is far enough
north and the air over our region is so dry that we are not
expecting showers or thunderstorms as this system passes by. The
threat for record breaking heat will continue into Sunday, Monday
and Tuesday with greater than a 60% chance of temps greater than 95
across the eastern Magic Valley and Snake Plain. Model ensembles
indicate at least a 60% chance that the ridge will break down
Wednesday into Thursday as an upper level trough digs into the
Pacific Northwest. Odds that our highs on Thursday will be lower
than 90 are around 75% and lower there`s a 25% chance that the highs
will be lower than 80. Just depends upon how deep the trough is as
it moves through the region. At this time, precipitation chances
look slim as much of the moisture will dissipate as the low pushes
into the ridge. Breezy conditions are likely for Wednesday and
Thursday with NBM 4.1 indicating at least a 50% chance of peak wind
gusts greater than 20 mph.
Valle
&&
.AVIATION...A bone dry air mass will keep clouds out for not only
the next 24/30 hours, but into Sat morning. Thus there is only the
slight impact of reduced visibility due to HZ/FU from nearby fires,
which should be at its worst when inversions set in and trap the
smoke. Wild fires should be active overnight with poor humidity
recovery in many locations. So the main driver for FM groups is wind
shifting and decreasing for the overnight. The gusty wind started
this morning and will continue into the early evening. However, wind
is very light starting by midnight tonight and all of Fri under
this very strong upper level ridge. Messick
&&
.FIRE WEATHER...Dry trough moving through western Montana brought
fairly gusty wind along with the extreme warmth and dryness. The
warmth and dryness are not going anywhere until mid-week of next
week, maybe. so the main forecast issue is wind. Tomorrow is a very
calm, stagnant day, which may cause smoke/air quality issues with
little drifting/scouring of the lower atmosphere. Another upper
level low makes its approach on Saturday, boosting wind in the
central Idaho mountains for Sat, then the Snake River plain/eastern
Magic Valley and southern highlands for Sun. For now, have issued a
Fire Weather Watch for the central Idaho mountains. Next chance for
some moisture appears to be Wed afternoon with the next upper level
low. Messick
&&
.PIH WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until midnight MDT Sunday night for IDZ051>059-075.
Fire Weather Watch from Saturday afternoon through Saturday
evening for IDZ422-475-476.
&&
$$
Area Forecast Discussion
National Weather Service Pueblo CO
257 PM MDT Thu Sep 1 2022
.SHORT TERM...(This evening through Friday)
Issued at 256 PM MDT Thu Sep 1 2022
Key Messages:
1) Continued warm through Friday.
Currently...satellite imagery shows widespread cumulus cloud
development over the Mountains this afternoon. A few weak echoes
are noted over the Central Mountains, mainly over Saguache County.
Areas over the Mountains will likely only see a few sprinkles as
these cells pass. Clear conditions exist on the Plains, where
temperatures are currently in the upper 80s to mid 90s.
Rest of today and tonight...upper level high pressure will continue
to spin over the Great Basin, with broad northerly flow across
Colorado. Weak energy moving south will keep the threat of isolated
light showers and thunderstorms over the Mountains into this
evening. Any convective activity should dissipate by sunset this
evening, with dry conditions prevailing overnight into Friday
morning. Overnight lows tonight will fall into the upper 50s to
lower 60s across the Plains, and 40s across the San Luis Valley.
Friday...the upper level high will slowly shift east into Utah
through the day. Another wave of embedded energy is forecast to
drop south across Colorado, leading to an uptick in Mountain
convection. Scattered showers and thunderstorms will initiate by
mid afternoon over the Mountains. Wind gusts to 40 mph and
lightning will be the main storm concerns. Hot conditions will
prevail across the Plains, where afternoon highs in the lower to
upper 90s are expected. As for precipitation, the latest high-res
model guidance holds off on thunderstorm activity on the Plains
until late afternoon to early evening. At this time, expected
precipitation chances to be nil on the Plains until after 00z/Sat.
Mozley
.LONG TERM...(Friday night through Thursday)
Issued at 256 PM MDT Thu Sep 1 2022
Key messages:
1) Isolated evening thunderstorms will be possible over the plains
and along on Friday. Main threat with these storms if they develop
would be strong and gusty outflow winds to 50 mph or greater.
2) Only a few PM thunderstorms will be possible over the mountains,
mainly the central mountains on Sunday and Monday.
3) Isolated to scattered PM thunderstorms over the mountains will be
possible on Tuesday through Thursday, mainly over the southern
mountains and Raton Mesa area. There is a slight chance that
tropical moisture could enhance thunderstorms over the region by
later in the week.
4) Temperatures will be right around the seasonal average or perhaps
just slightly above from the weekend and into the end of next week.
Detailed discussion:
Friday night through Saturday morning...
A weak mid level wave with enhanced moisture at the 500-700 mb level
will allow for the opportunity for a storm or two to make it back
into the central and eastern plains by later in the evening as there
continues to be destabilization by this time. With enough residual
moisture around in the mid levels, an isolated storm or two over the
eastern mountains I-25 corridor or cannot be ruled out. A jet finger
of stronger winds aloft at the 300 mb level will also be moving down
through central Colorado and the convergent quadrant will be located
over the eastern plains, which may also help to fuel thunderstorm
development over this area. MLCAPE does not look to be overly
impressive, but there will be better bulk shear of around 40 kts in
some locations, which might help to strengthen some of the storms.
Given some areas of higher DCAPE of around 2000 J/kg, the main
threat of a stronger storm will be strong outflow winds of 50 mph or
greater. It does appear with a general consensus between the models
that storms should be weakening and moving out of the CWA into the
very early morning hours on Saturday, which is reflected both in the
HRRR and NAMNest to be continuing until around 3 to 4 AM. The
NAM12 also keeps some showers around throughout the later hours of
the morning (around 11 AM) over the southern mountains but this
might be a little bit of a stretch since it appears in many of the
other models that are drier by that period in the forecast. The
CAPE values do appear to be more favorable at around 1000 J/kg
over this area for convective development, so it is possible that
if the NAM12 does verify that there may be storms developing
around this time.
Saturday afternoon through Monday...
There will still be enough mid level moisture around behind the
passage of the trough to allow for thunderstorms to form and become
scattered over the mountains and high valleys by the afternoon on
Saturday. There will also be some isolated storms moving out over
the San Luis Valley under the northeasterly flow. The ridge is going
to continue to build and take on a more positively tilted axis
throughout early next week, which will allow for drier air to be
advected in from the northeast in the mid levels and suppress the
recycled mid level moisture more to the west. Subsidence will also
help to hinder the development of any convection and only orographic
forcing will allow for a few thunderstorms to be possible over the
mountains, mainly over the southern mountains and Raton Mesa area on
central mountains on Sunday and Monday. The northeasterly flow
aloft, which will be mixed down to the surface in the east and
southeasterly flow, will allow for relatively cooler air to be
advected in. This will help to allow for temperatures to be closer
to the seasonal average, or just slightly above, through Monday.
Tuesday through Thursday...
Both the ensembles and deterministic models are in close agreement
with the ridge continuing to propagate eastward with a positively
tilted axis and force a cut off upper level low that moves just to
the south and east of Colorado. Depending on the position of this
U/L low will determine whether or not there could be some
thunderstorms possible over the plains on Tuesday afternoon although
it is appearing with the most recent EPS and GEFS ensemble members
that the majority of the members keep the low to the south over
northern Texas and New Mexico, which will advect in more drier air
from the northeast and help to limit the amount of thunderstorm
development over the plains. Only isolated thunderstorms will
continue to be more confined to the mountains. The troughing
upstream over the northwestern CONUS is looking to help prevent the
U/L wave from transitioning closer to Colorado. Looking a little
ahead in past the forecast period, there are signs of a tropical
system moving up from the Gulf of California which may help to
advect in more moisture over Colorado by the end of next week and
into next weekend and help in increase the chance of PM
thunderstorms. However, it is still too far out to be considered
reliable at this time and all ensembles, including the Canadian, are
showing the brunt of the moisture remaining to the south at this
time. Temperatures will remain just around, or slightly above, the
seasonal average for this time of year. -Stewey
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 256 PM MDT Thu Sep 1 2022
VFR conditions at all three terminals through the next 24 hours. A
few mid level clouds will prevail this afternoon. Wind gusts at
KCOS and KPUB of near 20 kts will continue this afternoon,
dissipating this evening. At this time, KCOS and KPUB should remain
dry through 00z/Sat. A few thunderstorms may be possible at KALS
Friday afternoon, but confidence in occurrence is low at this time.
Mozley
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...MOZLEY
LONG TERM...STEWARD
AVIATION...MOZLEY
Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
947 PM MDT Thu Sep 1 2022
.UPDATE...
Issued at 441 PM MDT Thu Sep 1 2022
Based on radar and CAMs, have added some slight chance PoPs to
portions of the CWA tonight into Friday morning. Satellite and a
peak out the window shows haze from western wildfire smoke, and
HRRR smoke forecast indicates this persisting into Friday morning
as well, so have added mention in the forecast.
&&
.DISCUSSION...(This Evening Through Thursday)
Issued at 243 PM MDT Thu Sep 1 2022
Upper ridging continues across the western CONUS, centered across
the Great Basin. Northwest flow also continues across the northern
Great Plains. A series of upper waves are crossing eastern MT/WY
into the CWA. Ahead of the wave, isolated showers and thunderstorms
have developed across northeast WY through the Black Hills area.
With inverted V signature in forecast soundings, cloud bases around
12k ft and surface RH in the 10-25% range, most of the precip is
falling as virga, evaporating before it hits the ground. Have
adjusted isolated pops for this afternoon and evening for coverage,
which will end by 03z tonight. A weak cold front will push through
tonight, bringing cooler temps the next two days, but still above
seasonal averages. Surface high pressure will then park over the
Upper Midwest Sunday through the first half of next week. This will
bring continued southerly flow and temperatures well into the 90s to
near 100 through the middle of the week.
&&
.AVIATION...(For the 06Z TAFS Through 06Z Friday Night)
Issued At 947 PM MDT Thu Sep 1 2022
Isolated showers will continue across portions of the CWA tonight,
but conditions are expected to remain VFR. Haze from western
wildfire smoke will persist into Friday morning as well.
&&
.FIRE WEATHER...
Issued at 243 PM MDT Thu Sep 1 2022
Elevated fire weather conditions are expected through early next
week due to temperatures well above average and very dry minimum
afternoon minimum relative humidities.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...None.
WY...None.
&&
$$
Update...Pojorlie
DISCUSSION...13
AVIATION...Pojorlie
FIRE WEATHER...13