Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/24/24
Area Forecast Discussion
National Weather Service Boise ID
845 PM MDT Fri Aug 23 2024
.DISCUSSION...Short wave trough extending from a deep upper
low on the Oregon coast pivoted northward through our CWA this
afternoon and evening with showers, thunderstorms, and gusty
outflow winds in eastern Oregon and western-most Idaho. The
trough was moving into Washington this evening and weather was
calming down in our CWA. Cool air has already reached our CWA
but even cooler air will come in Saturday as the main upper low
moves inland. Showers will increase Saturday and Saturday
evening but with only a slight chance of thunderstorms as cooler
air will already be in place near the surface. The weakening
upper low will shift slowly eastward and exit our area Sunday
night. Cool air will continue through Sunday along with a
decreasing chance of showers. Winds will be light through the
weekend. Latest HRRR model keeps near-surface smoke close to the
active fires in the Boise and Payette National Forests through
Saturday night, but expands it southward into the Snake Basin
east of Boise on Sunday. No updates to current forecast needed
at this time.
&&
.AVIATION...Generally VFR except local MVFR/IFR and mountain
obscuration due to smoke in ID north of the Snake Basin.
Scattered showers ending south to north by 04Z, but redeveloping
in Oregon after 10Z Saturday and in Idaho after 15Z Saturday.
Higher mountains becoming locally obscured. Surface winds: W-SW
10-20kt through 06Z then decreasing. Winds aloft at 10kft MSL:
SW 20-30 kt.
KBOI...VFR. Surface winds, generally west around 10kt with
LLWS until 06Z. Scattered showers after 15Z Saturday.
Sunday Outlook...Local MVFR/IFR and mountain obscuration due
to smoke. Showers may produce MVFR to IFR conditions in Idaho
mountains Sunday. Winds generally W to NW 5-15 kt. Winds aloft
at 10kft: SW to W 10-20 kt.
&&
.PREV DISCUSSION...
SHORT TERM...Tonight through Sunday night...Showers and
thunderstorms this afternoon will transition out of the area as
an upper shortwave trough swings into n-central Idaho. Through
early evening storms will be capable of producing gusts of 50
to 60 mph and hail. The main focus for development will be
e-central Oregon, the lower Snake Plain, and the w-central
Idaho mountains through this evening. In the Snake Plain, Boise
will be on the eastern edge of storm activity and outflow winds.
The main low, positioned along the Oregon coast this afternoon,
will push inland overnight, tracking into NW Nevada by Saturday
afternoon. The focus of precipitation development tonight will
be across SE Oregon spreading into SW Idaho on Saturday.
Daytime,heating and cold air aloft will support showers and
thunderstorms across the region Saturday afternoon/evening.
Weaker flow aloft and a cooler, more moist surface layer will
reduce outflow wind potential on Saturday. Precipitation shifts
into the w-central Idaho mountains on Sunday as the low lifts
into eastern ID. High temperatures Saturday and Sunday will be
15 to 20 degrees below normal.
LONG TERM...Monday through Friday...Monday and Tuesday will see
a return to dry and warmer weather under a strengthening west-
southwest flow. Cooler conditions return with the passage of an
upper trough and accompanying dry cold front Wednesday. A
trailing weak wave in northwest flow will keep temperatures
below normal on Thursday. From there an upper ridge will begin
to build over the western U.S. bringing a return to hot and dry
weather into next weekend.
&&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...Red Flag Warning until 9 PM MDT this evening
IDZ420-423-424-426.
OR...Red Flag Warning until 9 PM MDT /8 PM PDT/ this evening
ORZ636-637.
&&
$$
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DISCUSSION...LC
AVIATION.....LC
SHORT TERM...DG
LONG TERM....DG
Area Forecast Discussion
National Weather Service Cheyenne WY
752 PM MDT Fri Aug 23 2024
.KEY MESSAGES...
- Scattered to numerous showers and thunderstorms are expected
on a daily basis through Sunday, some with locally heavy
rainfall. Isolated strong to severe thunderstorms will be
possible as well.
- Elevated to near critical fire weather conditions over Carbon,
Converse, and Niobrara counties with gusty southwest winds
this weekend.
- A chance of late day showers and thunderstorms will occur on
Monday, then dry weather will develop for Tuesday through
Friday. The warmest days will be Tuesday and Wednesday.
&&
.UPDATE...
Issued at 751 PM MDT Fri Aug 23 2024
Strong southwest winds still look good for Saturday across much
of southeast Wyoming. Confidence high enough to upgrade Fire
Weather Watches to Red Flag Warnings...so dec ided to do so.
Updates have been sent.
&&
.SHORT TERM /THROUGH SUNDAY NIGHT/...
Issued at 400 PM MDT Fri Aug 23 2024
The active monsoon weather pattern continues across the area today.
Current satellite imagery shows moisture streaming over the area out
of the core monsoon region of the Four Corners states. Meanwhile,
there is a narrow dry patch across Utah and western Wyoming visible
in the water vapor channel, while another area of moisture is seen
circulating around the strong closed low currently located just off
of the Oregon coastline. At the surface, a low pressure system is
developing near Billings, MT, while high pressure builds into the
Colorado Rockies. A surface pressure trough extends south from the
low center towards Lusk and then towards Pine Bluffs. Rapid pressure
rises behind this are shifting eastward, and providing the focus for
storm development this afternoon. So far, storms are moving through
the more marginal environment present in Wyoming. While moisture is
abundant with near saturated soundings, instability, lapse rates,
and shear are all fairly marginal. Expect storms to shift eastward
as the pressure trough moves east through the afternoon. Once storms
approach the state line, they will start to encounter a more
favorable environment for strong to severe storms. In far eastern WY
and the NE panhandle, MLCAPE exceeds 1000 J/kg and approaches 2000
J/kg in Cheyenne county. Shear and lapse rates are still marginal,
but it should be enough to get a few storms to strong to severe
thresholds. The abundant moisture will also lead to a torrential
rainfall and localized flash flooding chance. Expecting these storms
to develop into a linear feature in the next hour or so, then then
move east through the panhandle through about 8-9PM, though a few
showers may linger later in the evening.
We`ll start to see some changes in the stagnant weather pattern this
weekend as the strong upper level low translates eastward tonight
into Saturday. Strong southwest flow throughout the atmosphere will
move over central Wyoming. This is also collocated with the dry air
patch currently visible on GOES water vapor channels. The dry
and windy air will push over our western zones, particularly
Carbon and Converse counties, while the monsoon plume tilts
eastward ahead of it, keeping decent moisture aloft over the
remainder of the area. Saturday looks like a pretty windy day
further west, with south to southwest 700-mb winds around 30 to
40 kts producing widespread strong winds at the surface. Some
mountain wave activity and downslope enhancement should lead to
wind gusts to 50+MPH in Carbon county. Can`t rule out areas from
Rawlins to Elk Mountain along I-80 exceeding high wind
criteria, but do not have the confidence to issue any high wind
headlines. However, the gusty winds and drier air mixing into
the boundary layer will increase fire weather concerns for these
western zones. Thus, a Fire Weather Watch has been issued for
Converse and Niobrara counties where RH is a bit lower. Further
east, the main thing for Saturday will be afternoon
thunderstorms once again. The RAP model and a few other HiRes
models show the surface trough setting up from roughly Cheyenne
to Rapid City, SD during peak afternoon heating. This looks like
it will provide the focus for storm development, though we will
need to watch for some high based activity further west for a
strong wind threat also.
Sunday looks similar as the close low inches closer. By this time,
the moisture ahead of the upper level low will merge with the
monsoon moisture, mostly wiping out the dry air pocket in between.
Column moisture will remain above average for most of the area, and
a few vort-maxes moving through the flow aloft will help to trigger
another round of afternoon showers and thunderstorms that may
continue into the evening or overnight hours.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
Issued at 400 PM MDT Fri Aug 23 2024
Monday...A shortwave trough aloft moves into the Dakotas with some
drier air filtering into our forecast area as evidenced by the
precipitable water values lowering to 0.2 to 1 inch. It looks like
enough low and mid level moisture for isolated to widely scattered
late day showers and thunderstorms, most numerous from the Snowy
Range to Laramie County. Somewhat cooler with 700 mb temperatures
near 12 Celsius.
Tuesday...The GFS may be erroneously increasing moisture and thus
increasing thunderstorm coverage, but for now, will match with our
neighbors and keep it dry. With an increase in 700 mb temperatures,
maximum temperatures will be warmer.
Wednesday...Continued dry with west southwest flow aloft and a
relatively dry airmass overhead. The warming trend continues with
700 mb temperatures near 14 Celsius.
Thursday/Friday...The lower and mid levels look to remain relatively
dry looking at precipitable water values, thus we will continue a
dry forecast. Somewhat cooler on Thursday in the wake of a passing
cold front and 700 mb temperatures near 7 Celsius, with a warming
trend for Friday.
&&
.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1116 AM MDT Fri Aug 23 2024
VFR conditions currently across area terminals with BKN cloud
cover across much of Carbon Co. Gusty southwest winds around 25
kt today for southeast Wyoming terminals with afternoon
thunderstorms developing along the higher terrain. Latest CAMs
have been suggesting a line of storms developing along the
Laramie Range moving east in the Nebraska panhandle this
evening. KCYS and KSNY appear to be the terminals most likely to
see -TSRA with reduced flight conditions for a 1-2 hour period
later today. Most remaining area terminals have VCTS/VCSH
through 06z tonight with SCT-BKN upper level clouds remaining in
place overnight.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...Red Flag Warning from noon to 9 PM MDT Saturday for WYZ417-418.
NE...None.
&&
$$
UPDATE...GCC
SHORT TERM...MN
LONG TERM...RUBIN
AVIATION...MB
Area Forecast Discussion
National Weather Service Pueblo CO
603 PM MDT Fri Aug 23 2024
.KEY MESSAGES...
- Isolated to scattered showers and thunderstorms will be possible
the rest of today into this evening.
- More showers and storms for Saturday along with warm
temperatures. Stronger to severe storms possible over the
higher terrain.
- Daily afternoon showers and storms expected during the long
term period, with greatest coverage along the mountains.
&&
.UPDATE...
Issued at 551 PM MDT Fri Aug 23 2024
Updated precipitation chances across the lower elevations
through the overnight hours. Most high-res model guidance
remains dry, with a few showers or thunderstorms across the far
eastern plains through 8 PM. Not much in the way of impacts from
this activity other than brief rainfall. Did keep showers and
isolated thunderstorms out along the Continental Divide. A
couple rounds of precipitation will be possible out west as an
upper wave moves across the region. Mozley
&&
.SHORT TERM /THROUGH SATURDAY/...
Issued at 212 PM MDT Fri Aug 23 2024
Southwest flow aloft will increase across our area today as a broad
upper high pressure moves off to our southeast. Meanwhile, an upper
low spins along over the Pacific Northwest, slowly but surely making
its way south. As a result, plenty of monsoon moisture will continue
to move into our area today and allow for more showers and storms.
Models are a bit lacking in coverage this afternoon and evening,
mainly due to a cap in place over much of the eastern plains.
However, looking at convective parameters in the high-res guidance,
some conditions may be more supportive of convective activity,
especially out east. The HRRR and NAM Nest both show little in the
way of instability over and west of I-25, just a few hundred J/kg of
CAPE. However, instability maximizes along and just west of the
Colorado-Kansas border, with 1500 to as much as 2500 J/kg of CAPE of
more in places where surface flow is more southeasterly. A good 20-
25 knots of bulk shear will be present across the area throughout
the day, thanks to the breezy southwest winds aloft, but some areas
will see slightly higher values, particularly around Kiowa and
Prowers Counties. This coincides pretty well with the areas under a
marginal risk of severe weather today.
Showers and storms will initially form over the higher terrain this
afternoon. We may see some gusty outflow and pockets of locally
heavy rainfall across some parts of the Continental Divide. As
steering flow pushes storms east onto the plains, these conditions
will continue, mainly over the Palmer Divide and parts of our
southern counties. However, if storms manage to persist out to our
eastern borders, conditions will be very favorable for rapid
intensification. Localized stronger to severe storms could produce
outflow winds to 70 mph, large hail, and heavy rainfall.
Flash flooding may still be a concern as well over burn scars and
other vulnerable areas due to ample monsoon moisture in the area.
High temperatures today will be warm again, in the mid-high 90s out
east while the higher terrain sticks to the mid-70s to mid-80s.
The pattern stays largely consistent on Saturday, though flow aloft
turns a bit more southerly as the upper low digs to the south. As a
result, the eastern plains will be a bit drier, though some activity
is still possible. Showers and storms will form in the mid-late
afternoon over the higher terrain before moving northeast. With
plenty of moisture still in place, heavy rainfall and flash flooding
may still be a concern. Otherwise, stronger to severe storms will be
possible over the higher terrain thanks to orographically-enhanced
lift and the additional energy supplied by the incoming trough. Out
east, some thunderstorms will still move across the plains, though
with a much lower chance for any severe weather. High temperatures
will be similar to today`s, though a few degrees warmer, with some
places over the far eastern plains approaching or exceeding 100
degrees.
&&
.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
Issued at 212 PM MDT Fri Aug 23 2024
Saturday Night - Thursday: Active weather is anticipated through
much of the long term period for south central and southeastern
Colorado. Overall, moist southwest flow will be in place as a ridge
of high pressure sits to the southeast of the region. While
there will be waves within the flow that may influence the area,
the stream of moisture and southwest flow will mostly persist.
With that all said, given the moisture stream, and forcing from
orographics and the waves, along with diurnal upsloping, daily
afternoon and evening showers and thunderstorms are anticipated.
The greatest coverage of showers and storms will be along the
mountains, where any forcing will be strongest. Strong winds,
small hail, and heavy rain are expected with any stronger
thunderstorms, especially Sunday, when a subtle wave will bring
an uptick in shear and allow for some better storm organization.
With that all said, showers and storms will dissipate during
the mid to late evening hours as any instability and forcing
wane. Looking at temperatures, more seasonal values are
anticipated. With the wave passages, a couple of cold front will
drop southward, one during the Sunday - Monday timeframe, and
another around the Thursday timeframe. These features will help
keep cooler air in place, and allow for temperatures to hover
around seasonal values.
&&
.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 514 PM MDT Fri Aug 23 2024
KALS...a few showers will be possible across the San Luis Valley
including the terminal through this evening, especially after
02z. Briefly reduced CIGS and VIS will be possible with any
showers that move across the terminal. Gusty southwest winds are
expected on Saturday afternoon along with isolated thunderstorm
activity.
KCOS and KPUB...breezy conditions early this evening will
dissipate for the overnight and early morning hours. Increasing
mid and high clouds are expected overnight, however, dry
conditions are forecast to prevail. Gusty southwest winds will
will develop by early to mid afternoon at both terminals, with
low chances for showers or thunderstorms by late afternoon.
Mozley
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...MOZLEY
SHORT TERM...GARBEROGLIO
LONG TERM...SIMCOE
AVIATION...MOZLEY
Area Forecast Discussion
National Weather Service Salt Lake City UT
313 PM MDT Fri Aug 23 2024
.SYNOPSIS...The last day of a monsoon surge will bring the threat
of strong thunderstorms to southern and eastern Utah through this
evening. Meanwhile, high end critical fire weather conditions
continue across western Utah...along with strong, gusty winds.
Another round of strong, gusty winds can be expected across much
of the region Saturday.
&&
.SHORT TERM (Through 12Z Sunday)...The last day of the latest
monsoon surge is on tap today...with a quick decrease in PW values
through the afternoon and evening from west to east. Afternoon
upper air and satellite analysis indicates broad upper level
diffluence across the region. A deep, anomalously strong upper
level trough is nearing the Oregon Coast.
With SBCAPE values nearing 2000 J/kg (or up to 3000 J/kg if you
believe the latest RAP analysis) and deep layer shear on the order
of 45-50kts, the set up is more than sufficient for strong,
organized thunderstorms capable of strong winds and large hail. In
addition, given the anomalously high PW values (on order of
150-200% of normal), stronger storms and/or training cells will be
capable of producing flash flooding.
Not to be out done, the western side of the state is experiencing
very strong winds with wind gusts in excess of 60 mph across the
Tooele Valley and the Great Salt Lake Desert. Strong gusty winds
will continue into Saturday, though valley floors and other lower
elevation areas may see winds decrease substantially for the
overnight period. A high wind warning was issued for the Great
Salt Lake Desert and Tooele and Rush Valleys. Wind advisories
continue for many valleys of the state Saturday.
Given single digit humidities and very strong winds, high end
critical fire weather conditions continue for the western portion
of the state into the evening. Overnight recoveries will be
poor...with another round of high end critical fire weather
conditions Saturday. Red Flag Warnings continue to be in effect.
.LONG TERM (After 12Z Sunday), Issued 331 AM MDT... The period
begins with an anomalously deep trough over the Northern Rockies
and Great Basin. With the trough axis along the Nevada/Utah state
line, enough residual moisture will be present to support a chance
for afternoon showers and thunderstorms over southeast Utah, with
some potential over the Uinta Mountains as well, where snow level
could dip to around 11 thousand feet. With dry air in place over
extreme southwest Utah, some potential will still exist for
critical fire weather conditions, but even 75th percentile winds
remain just below criteria.
Generally dry weather is expected on Monday and Tuesday, as roughly
90 percent of ensemble solutions favor a generally flat ridge over
the Great Basin, with an associated dry westerly flow. The remaining
10 percent suggest a more amplified ridge with some returning mid
level moisture.
Greater uncertainty emerges for Wednesday, and especially Thursday.
Roughly 75 percent of ensemble solutions favor yet another trough
sweeping across the Northern Rockies into the Northern Plains, with
the remaining 25 percent offering a somewhat deeper and slower
solution, with moisture advecting into southern Utah. Given
uncertainty, low chances (20-30 percent)for precipitation over
southern Utah on Wednesday and Thursday seem appropriate.
&&
.AVIATION...KSLC...Drier air moving into the region yields a more
limited convective chance through Friday evening. Further drying
will result in very minimal convective chances Saturday. Biggest
impact at terminal likely with gusty southerly winds. During the
daytime both Friday and Saturday, generally expect sustained
southerly values around 20-30 kts with gusts 30-40 kts or so.
Overnight, gusts may become more periodic, but times where surface
flow relaxes may then yield low level wind shear concern given the
strong winds remaining 1-2+ kft AGL.
.REST OF UTAH AND SOUTHWEST WYOMING...Any lingering convection
gradually expected to wane this evening, with clearer conditions
overnight as drier air continues to move in. Southerly wind gusts at
many locations will persist, though potentially become more periodic
in nature overnight (especially at more sheltered terminals). If so,
will see some possibility for low level wind shear concern given
that low level flow 1-2+ kft AGL will remain quite strong (roughly
30-40 kts or so). Further drying will result in convection becoming
even more isolated Saturday, but strong wind gusts (many terminals
in the 30-40 kt range) will continue during much of the day.
&&
.FIRE WEATHER...A relatively high end period of critical fire
weather conditions will continue through this evening with strong
winds and single digit humidities across western Utah. Poor
overnight recoveries are expected tonight, with an average of
20-30% humidities. Another day of high end critical fire weather
conditions is expected Saturday afternoon and evening, with
widespread gusts in excess of 50-55 mph and humidities in the
single digits to low teens. A cold front will cross the area
Sunday, bringing cooler, almost fall-like temperatures.
&&
.SLC WATCHES/WARNINGS/ADVISORIES...
UT...Red Flag Warning until midnight MDT Saturday night for UTZ478-
492-495.
High Wind Warning until 10 PM MDT Saturday for UTZ101-102.
Wind Advisory until 10 PM MDT Saturday for UTZ103-115-122.
Wind Advisory from 11 AM to 10 PM MDT Saturday for UTZ104-105-
119>121-126-129-130.
WY...Red Flag Warning from noon to 9 PM MDT Saturday for WYZ277.
&&
$$
Kruse/Warthen/Barjenbruch
For more information from NOAA`s National Weather Service
visit... http://weather.gov/saltlakecity
Area Forecast Discussion
National Weather Service Topeka KS
608 PM CDT Fri Aug 23 2024
.KEY MESSAGES...
- Heat Advisory has been issued for Saturday and Sunday with
heat indices forecast to reach 105-110 degrees.
- Still hot on Monday, followed by gradual improvement
throughout the work week.
- Small rain chances exist in far northern and eastern KS
overnight into Saturday morning; otherwise chances remain low
until Thursday.
&&
.DISCUSSION...
Issued at 255 PM CDT Fri Aug 23 2024
This morning`s showers and isolated storms have finally pushed east
of the area early this afternoon leaving a mix of clouds and sun,
though northeastern portions of the area have been slower to clear
out. Those locations won`t have as much time to reach the 80s and
may struggle to do so, whereas southern and western locations could
still reach around 90 degrees.
Heading into Saturday, the upper ridge dominating the Southern
Plains will start to have more of an influence on our local weather.
Overnight into the morning, embedded vorticity maxima are progged to
eject out of the trough off the west coast and into the southwest
flow over the Rockies, helping to deepen sfc low pressure in
southwest KS. A 40 kt LLJ is also progged to develop and usher in
warmth and moisture. The nose of the jet looks to set up the better
speed convergence towards the KS/NE border overnight before
weakening around sunrise. The HRRR appears to be the only one of the
CAMs depicting spotty showers across the area overnight, whereas
most other guidance favors north of the border. Have focused PoPs in
our northern tier of counties before sunrise as this lines up with
where the better ascent should be. After sunrise through late
morning, the rain chances shift mainly east of the area along an
axis near or east of the KC metro. This is where the best isentropic
lift resides by that time, as well as the moisture axis. Have kept
small PoPs in far eastern portions of the area, though HREF members
have generally favored this activity to stay east with the exception
of the HRRR.
The aforementioned rain chances and lingering cloud debris led to a
bit of uncertainty on heat potential in far eastern portions of the
area, but with the rain more likely east, current thinking is that
its impacts on temperatures here should remain minimal. Dew points
look to be higher in eastern locations as well, so combining the hot
and humid conditions leads to heat indices forecast in the 105-110
degree range area-wide. Sunday may see slightly lower dew points but
hotter temperatures with a thermal ridge overhead, so heat indices
look similar. As such, a Heat Advisory has been issued for the
entire area Saturday afternoon through early Sunday evening.
A weak frontal boundary looks to develop in the Plains Monday, but
it may struggle to actually reach our area, especially early enough
to have a meaningful impact. Highs are still forecast in the upper
90s with slightly lower dew points again, so will need to keep an
eye to see if heat headlines would be needed for part of the area
that day as well. Subtle perturbations ejecting out of the main
trough axis out west could bring on and off rain chances early in
the work week, which could impact temperatures as well. However,
there is still enough variation in the guidance to keep PoPs low
through Wednesday. The upper ridge at least looks to flatten during
that time frame and lose its grip on us, helping to bring a gradual
cooling trend through the week. By Thursday and especially Friday,
we should see more meaningful relief as the main trough pushes a
stronger cold front through the area with better (30-40%) rain
chances.
&&
.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 608 PM CDT Fri Aug 23 2024
VFR conditions are expected through the period. Winds southeast
under 10kts becoming south around 14kts with gusts up to 23kts
after 15Z.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
Heat Advisory from 1 PM Saturday to 8 PM CDT Sunday for KSZ008-
KSZ009-KSZ010-KSZ011-KSZ012-KSZ020-KSZ021-KSZ022-KSZ023-KSZ024-
KSZ026-KSZ034-KSZ035-KSZ036-KSZ037-KSZ038-KSZ039-KSZ040-KSZ054-
KSZ055-KSZ056-KSZ058-KSZ059.
&&
$$
DISCUSSION...Picha
AVIATION...53