Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/09/25
Area Forecast Discussion
National Weather Service Bismarck ND
844 PM CDT Tue Apr 8 2025
.KEY MESSAGES...
- Critical fire weather conditions are possible across the
southwest and parts of the south central on Wednesday.
- 20 to 30 percent chance of rain showers Wednesday.
- Breezy to windy conditions are expected through the end of
the work week.
- Temperatures will continue warming through the end of the
week, with a cooler and more active period starting Sunday.
&&
.UPDATE...
Issued at 844 PM CDT Tue Apr 8 2025
Another narrow line of showers has entered western North Dakota,
though like the previous, this one is also mostly virga with a
few exceptions. The primary exception is in the southwest where
a few showers have been a little more organized, and a
lightning strike was even observed as well. CAMs disagree in
whether or not this line will completely fall apart, or hold
together as it moves eastward. Regardless, far more areas are
expected to remain dry than receive any measurable
precipitation.
UPDATE
Issued at 633 PM CDT Tue Apr 8 2025
A line of showers, essentially along and near Highway 83,
continues passing through the area west to east. Despite a few
observations reporting brief light rain/sprinkles, these
showers are mostly in the form of virga. All in all, the
forecast remains on track.
&&
.DISCUSSION...
Issued at 246 PM CDT Tue Apr 8 2025
This afternoon, an upper ridge axis was crossing over North Dakota,
while a surface trough and attendant cold front were moving through
western North Dakota. Ahead of the front, breezy southerly winds
persisted across our eastern counties, while along and behind the
front were scattered radar returns and somewhat gusty northwesterly
winds. The radar echoes already in North Dakota have not been
producing much, with cloud heights still around 10k feet. Ceilings
are a bit lower in eastern Montana, around 6 to 7k feet, where there
have been a few rain observations from automated sites.
This activity is expected to slowly push east through the afternoon
and evening as the front drifts through, although any rain amounts
will be very light. Can`t rule out a rumble or two of thunder in the
southwest, although SPC mesoanalysis page only shows instability
maxing out around 100 J/kg.
After the upper ridge moves out, a shortwave will quickly drop
through the area, potentially closing off as it does. As the low
closes off and pushes a cold front through the state, widely
scattered showers are forecast through Wednesday and Wednesday
night. Blended POPs are a broad 20 to 30 percent across the
majority of the forecast area, with the exception of the far
south. A few rumbles of thunder are possible with a couple
hundred J/kg of MLCAPE available per deterministic output. Any
precipitation from these showers is expected to be light, with
the probability of exceeding even 0.05 inches of QPF low, and
are favored across the north. Highs on Wednesday are forecast to
be in the lower 50s to the lower 60s, with gusty northwest winds
across the area. Forecast soundings are advertising around 40 knots
available at the top of the mixed layer, focused in southwest North
Dakota. Sustained winds top out right around 30 mph, while that
45 mph gust threshold for an advisory looks a bit more likely.
Not quite high enough confidence for a Wind Advisory at this
juncture, with no real strong signal in pressure rises or cold
air advection, but a modest surface pressure gradient from the
low closing off plus mix out could be enough. These winds,
combined with low relative humidity, led us to issue a Fire
Weather Watch for southwest and parts of south central North
Dakota for Wednesday afternoon and early evening. See fire
weather discussion below for details.
After precipitation chances taper off Wednesday night, a more
potent upper ridge builds in for the end of the work week. Highs
will be similar on Thursday, in the lower 50s to lower 60s, with
still breezy northwest winds but plenty of sunshine.
Temperatures quickly ramp up on Thursday, with very high
confidence in highs reaching the 70 F threshold across much of
western North Dakota, and 60s elsewhere. As the ridge begins to
collapse Friday evening, some low POPs emerge across the north,
although right now we carry a dry forecast through the daytime
hours on Saturday across most of the forecast area. Highs on
Saturday will still be pleasant, in the lower 60s to lower 70s.
Ensemble cluster analysis is in fairly good agreement on a trough
developing across the Northern Rockies sometime this weekend,
although there are a few different solutions regarding timing and
placement. However, the general implication is for widespread,
increasing chances for precipitation starting Saturday night and
continuing through Monday, and cooler temperatures to start
next work week. NBM temperature percentiles have a large spread
on Sunday, indicating uncertainty in the timing of a cold front,
before higher confidence in highs dropping to the 40s and 50s
on Monday. The 48-hour probability for at least 0.25 inches of
QPF is around 40 to 50 percent, with a low probability of
exceeding half an inch, although there is about a 10 percent
chance of exceeding an inch of QPF across northern North Dakota.
For right now, expecting more rain than snow for the bulk of
precipitation/QPF, with temperatures favored to stay warm enough
for predominantly rain until Sunday night into Monday.
&&
.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 844 PM CDT Tue Apr 8 2025
*update 0144Z*
A second line of showers has entered western ND this evening.
While they too are mostly virga, there are some more organized
showers in the southwest. As a result, used a TEMPO at KDIK for
an hour to illustrate these passing showers.
Original discussion:
A north to south line of showers is presently draped essentially
along Highway 83. A few observations are showing brief light
rain/sprinkles hitting the ground, however, these showers are
mostly in the form of virga at this point. Otherwise, expect
mostly quiet conditions and light winds to start the night.
Winds will begin to pick up later tonight resulting in windy
conditions during the day Wednesday. Initially, these winds will
be out of a more westerly direction before becoming more
northwesterly. There is a 20 to 30 percent chance of light rain
Wednesday afternoon, with the best chances further north.
&&
.FIRE WEATHER...
Issued at 246 PM CDT Tue Apr 8 2025
A Fire Weather Watch has been issued for Wednesday afternoon
into the early evening for southwest and parts of south central
North Dakota. Strong northwest winds sustained around 30 mph and
gusting up to 45 mph are expected, with the strongest winds over
our far southwest counties. Minimum relative humidity is
forecast to drop to around 23 percent, and the combination of
these two factors could lead to critical fire weather
conditions. Near critical fire weather conditions are possible
in the counties just north of those in the Watch area.
Although there are low chances for rain through the day, this is
expected to stay north of the Watch area, and even if there is a
brief shower earlier / further south than currently forecast,
the chance of rain amounts exceeding more than a few hundreths
is low, with the lowest probabilities across the southwest.
Winds could become gusty and erratic around any showers,
especially if they end up as virga, with RAP humidity forecasts
showing a dry layer just above the surface.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
Fire Weather Watch from Wednesday afternoon through Wednesday
evening for NDZ031>034-040>046-050.
&&
$$
UPDATE...Telken
DISCUSSION...Jones
AVIATION...Telken
FIRE WEATHER...Jones
Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
547 PM MDT Tue Apr 8 2025
.KEY MESSAGES...
- Showers and a few thunderstorms possible this afternoon into
tonight. More showers possible Wednesday. Chance for severe is
low, but small hail and strong winds still possible with storms.
- Elevated fire weather conditions expected Wednesday through the
end of the week.
- Pattern shift towards the end of the weekend will lead to cool
more active weather early next week.
&&
.DISCUSSION...(This Evening Through Tuesday)
Issued at 105 PM MDT Tue Apr 8 2025
Current upper air models show upper ridge over the Dakotas
breaking down as a shortwave just to our west moves into the
northern plains. Surface chart currently depicts low centered over
the MT/ND border with warm frontal boundary running south into
western SD this afternoon. Trailing cold front stretches from
southeastern MT down into central WY. Most recent radar scans
have light returns developing over northwestern SD near the
boundary. Winds are beginning to pick up out of the northwest for
areas behind the boundary, while areas ahead of the boundary have
light winds generally with an easterly component. Temperatures
currently sit in the 60s to low 70s across the FA.
Areas of showers expected to increase over the afternoon and
evening as cold front crosses the region. HRRR MU CAPE values in
the 100-300 j/Kg range, along with steepening mid-level lapse
rates and modest shear may spark an organized storm or two with
potential for small hail or gusty winds, though chances for severe
are low. Forecast QPF amounts have dropped somewhat, given limited
moisture with dewpoints in the low 30s. Convective showers could
bring still bring brief heavy rains with some localized potential
for a tenth of an inch or two. As instability decreases early this
evening, so will chances for thunderstorms, however showers may
persist and dissipate in the overnight hours.
Cooler temperatures are in store for Wednesday, with highs in the
50s to mid 60s. Another disturbance moving through the northern
plains will increase precipitation chances Wednesday afternoon
and early evening, mainly for the Black Hills into southwestern
and south central SD. A thunderstorm or two will be possible
again, with MU CAPE values in the 200-400 j/Kg range and 0-6km
shear of 40-50 kts. Tightening pressure gradient will bring gusty
winds Wednesday afternoon, with gusts 40 to 50 mph possible. Wind
headlines may be necessary, especially over northwestern SD.
Upper ridge builds over the western CONUS on Thursday, sliding
into the northern and central plains as we move into the weekend,
promoting a dry and warming trend. Highs on Friday and Saturday
reach into the 70s and possibly low 80s for some areas, bringing
elevated fire conditions in the afternoons the latter half of the
week. Saturday into Sunday, upper ridge exits the area as upper
trough moves into the northern Rockies and plains. Another
disturbance with this trough will lead to increased precipitation
chances and cooler temperatures moving in for early next week.
&&
.AVIATION...(For the 00Z TAFS Through 00Z Wednesday Evening)
Issued At 543 PM MDT Tue Apr 8 2025
Mainly VFR conditions are expected through the TAF period. Showers
and thunderstorms will cross the area early this evening. Brief
MVFR conditions and gusty, erratic winds possible near any
stronger showers/storms.
Breezy northwest winds will develop Wednesday morning across the
western SD plains. Gusts to 45 mph are possible across northwest
South Dakota. Showers and thunderstorms may redevelop across the
Black Hills area and southwest South Dakota Wednesday afternoon,
resulting in localized MVFR conditions. Otherwise VFR conditions
are expected through the forecast period.
&&
.FIRE WEATHER...
Issued At 105 PM MDT Tue Apr 8 2025
Gusty winds on Wednesday will lead to high to very high grassland
fire danger across the western and south central SD plains.
Elevated fire danger is possible late week (Thursday to Saturday),
as low humidities develop each afternoon, down to around 20
percent in many areas. Breezy conditions could develop each day
during the late morning and afternoon, especially across the SD
plains.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...Wind Advisory from 11 AM to 7 PM MDT Wednesday for SDZ001-002-
012>014-073-078.
WY...None.
&&
$$
DISCUSSION/KEY MESSAGES...Dye
AVIATION...13
FIRE WEATHER...Dye
Area Forecast Discussion
National Weather Service Las Vegas NV
707 PM PDT Tue Apr 8 2025
.SYNOPSIS...The ongoing warming trend will continue this week,
providing an early taste of summer as temperatures climb to around
10 to 15 degrees above normal each day. Relief will arrive in
time for the weekend as a passing system impacts the region, with
increasing winds Friday and Saturday, as well as gradually cooling
temperatures this weekend into early next week. No precipitation
is forecast the next seven days.
&&
.UPDATE...Current temperatures are around 5 degrees warmer than they
were at this time yesterday. Afternoon highs were around 10 degrees
above average for this time of year. Overnight lows will fall into
the 60s in the Las Vegas Valley and Colorado River Valley and into
the 50s in higher elevations of the Mojave Desert. Winds stay light
and skies remain mostly clear. No forecast updates are necessary at
this time.
&&
.SHORT TERM...through Wednesday night
The warming trend continues today, with temperatures this
afternoon on track to top out around 10 degrees above normal for
most, with locations across the mountains inching into the 70s,
while locations across the Colorado River Valley and Death Valley
climb well into the 90s. Winds remain relatively light, with
intermittent breezes expected through the afternoon. Latest water
vapor imagery and RUC 500 hPa analyses clearly indicate the low-
amplitude ridge encompassing the western CONUS, with moisture
aloft lending to waves of high clouds over the region. These
clouds will gradually dissipate and move northward overnight
tonight and Wednesday, with ensembles still in great agreement
regarding the evolution of the ridge, progged to continue building
over the region through Wednesday night. The net result will be a
continued increase in thicknesses and clearing skies as the
building ridge shunts Pacific moisture northward, along with a
corresponding uptick in temperatures. Highs Wednesday are expected
to top out a few degrees warmer than today across the board,
including the return of triple digits in Death Valley. Overnight
temperatures will also trend upward accordingly, though with lows
in the 40s and 50s across higher terrain and 60s and 70s across
the valleys, there will still be some semblance of relief from the
heat. As to be expected, no precipitation is forecast, with winds
remaining light for the duration.
.LONG TERM...Thursday through Monday
Temperatures continue to climb on Thursday and Friday as the ridge
builds. Highs will be 10 to 15 degrees above normal on Thursday
and 15 to 20 degrees above normal on Friday. Record daily high
temperatures and record warm low temperatures are threatened at
some area climate sites - see the Climate section below for
details. These temperatures will yield widespread Minor (Level 1
of 4) HeatRisk with pockets of Moderate (Level 2 of 4) HeatRisk
along the Colorado River, Death Valley, and other areas of lower
elevation in the Mojave Desert. This level of heat primarily
affects those that are sensitive to heat, have not had time to
acclimate to increased temperatures, or do not have access to
sufficient cooling or hydration. Remember to stay hydrated and
know where to find the nearest air conditioned space, especially
if spending time outdoors.
A significant change in the weather pattern arrives this weekend
as an upper level trough moves into the western United States
and the ridge exits to the east. Model ensembles are starting to
agree on the timing and placement of the trough and spread in NBM
output for winds and temperatures is decreasing. Overall, expect
increased southwesterly winds on Saturday and Sunday as well as
cooler temperatures going into early next week. How strong the
winds become and how much temperatures drop will depend on the
speed and depth of the trough, which should become more apparent
in the coming days.
&&
.AVIATION...For Harry Reid...For the 00Z Forecast Package...
Winds will largely remain rather light this evening and overnight. A
bit of a south/southwest wind push may result in a few gusts to 15
knots through around 03z, but otherwise expect winds 10 knots or less.
Wind direction will mainly be from the south/southwest, becoming
variable by 12z then shifting to the north/northeast by 17z-18z
Wednesday.
For the rest of southern Nevada, northwest Arizona and southeast
California...For the 00Z Forecast Package...Winds to remain
diurnally driven and 10 knots or less. The exceptions will be KDAG
and KEED/KIFP, where a few gusts of 15-20 knots may occur before 05z
Wednesday.
&&
.CLIMATE...Numerous climate locations have a forecast high
temperature and/or forecast warm low temperature within 3 degrees of
the daily record.
The table below shows the daily record maximum temperature and the
year the record was last set. An asterisk (*) denotes which records
are in jeopardy (within 3 degrees of the forecast).
MAX THU, APR 10 FRI, APR 11
Record (Yr) Record (Yr)
Las Vegas 91 (2014)* 93 (2023)*
Bishop 91 (1989) 86 (2018)*
Needles 103 (1989) 102 (1936)*
Daggett 99 (1989) 93 (2014)*
Kingman 91 (1907)* 96 (1936)
Desert Rock 91 (1989)* 87 (2014)*
Death Valley 110 (1989) 108 (1989)
The table below shows the daily record warm minimum temperature and
the year the record was last set. An asterisk (*) denotes which
records are in jeopardy (within 3 degrees of the forecast).
WARM MIN THU, APR 10 FRI, APR 11
Record (Yr) Record (Yr)
Las Vegas 70 (2002)* 72 (2018)
Bishop 48 (1951) 55 (1989)
Needles 70 (1989) 72 (2014)
Daggett 63 (1989)* 68 (1989)
Kingman 59 (1989) 66 (1989)
Desert Rock 63 (1989) 66 (2018)
Death Valley 80 (1972) 80 (2018)
&&
.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report
any significant weather or impacts according to standard operating
procedures.
&&
$$
UPDATE...Meltzer
SHORT TERM...Phillipson
LONG TERM...Meltzer
AVIATION...Austin
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