Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/18/24
Area Forecast Discussion
National Weather Service Cheyenne WY
427 PM MST Sat Feb 17 2024
.KEY MESSAGES...
1) Strong winds likely Sunday across the wind-prone areas,
potentially spreading east along the Interstate 25 corridor late
in the afternoon through the evening.
2) Winds will be breezy Monday before another potential round of
high winds across southeast Wyoming wind-prone locations
Tuesday.
3) Precipitation chances increase midweek.
&&
.SHORT TERM /THROUGH SUNDAY NIGHT/...
Issued at 245 PM MST Sat Feb 17 2024
Latest GOES Day Cloud Phase Distinction RGB shows clear skies
with snow cover across the majority of the CWA from yesterday`s
storm. Latest RAP analysis shows at 1032mb high over south-
central WY that has been leading to elevated gradients along the
Laramie Range. This, along with a mountain top inversion, has
led to elevated gap flow near Bordeaux on I-25. Gusts around 50
mph will continue to be observed through the afternoon with
drifting snow leading to slick roads. Temperatures remain in
the upper 20s and low 30s east of I-25 and near 20 farther west
as the high albedo snow cover has limited surface warming.
Temperatures will cool off quickly this evening, but may be
limited overnight as 700mb temps rise with the ridge axis aloft
shifting overhead and increasing cloud cover arrives from the
west. Regardless, low teens to single digits are likely, with
valley areas like Laramie dropping below zero once again.
Winds aloft will begin to increase early Sunday morning as
height and pressure gradients tighten ahead of a passing
shortwave. Looking at a bora-type event with mountain wave
activity evident along the Snowy and Laramie Range. Local random
forest guidance shows the potential for high winds across
southeast WY wind-prone locations beginning as early Sunday
morning (mostly gradient driven) with better parameters arriving
late in the afternoon. Could see winds spill out of wind-prone
zones as strong downward motion spreads eastward into the
foothills near the I-80/I-25 interchange Sunday evening.
One limiting factor involves the timing of this wind event. The
GFS and EC are slightly off on the timing of the shortwave
passage that could impact the timing of strongest winds.
Additionally, GFS 700mb winds appear on the high end of the GEFS
distribution so local guidance could be slightly inflated.
Regardless, hi-res guidance continues to show this high wind
potential at least for wind-prone locations, with the strongest
winds late Sunday afternoon into the evening.
For headlines, decided to upgrade to High Wind Warnings for
wind-prone areas including Bordeaux, Arlington, and the South
Laramie Range. Also included portions of Converse and Platte
County into the warning, especially for I-25 between Wheatland
and Casper as there could be a brief window of high winds as the
surface low passes just to the north Sunday afternoon.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
Issued at 245 PM MST Sat Feb 17 2024
Potential High Winds are forecast to decrease going into late
Monday morning, but will likely remain elevated in the primary
wind prone sites in southeast Wyoming and adjacent areas through
the day Monday. NBM decreases probabilities of greater than 50
mph wind gusts pretty quickly after 8 AM Monday. But, the
probability for greater than 40 mph wind gusts stay above 20-30
percent until near 2 PM Monday. Late Monday night to early
Tuesday, the GFS is showing a 140-150 kt jet pushing along the
CO/WY border with 40 to 55 kts mixing down to 750-800 mb. In
addition, with widespread adjacent north to south oriented areas
of positive and negative omegas across southeast Wyoming, the
development of mountain waves is possible. There are high
chances of High Winds in the primary wind prone sites in
southeast Wyoming and depending on how widespread the mountain
waves are, there could be mountain waves breaking as far east as
the WY/NE border. Confidence decreases outside of the three
main wind-prone areas of Arlington, Vedauwoo, and Bordeaux. NBM
is showing the chances for greater than 50 mph wind gusts
dropping off between 11 AM and 2 PM. Due to these strong west to
southwesterly downsloping winds, temperatures are forecast to
be well above normal with high temperatures in the 40s to 50s
across southeast Wyoming and 50s to low 60s in the Nebraska
panhandle.
Tuesday night, a quick-moving shortwave trough makes landfall on the
west coast and begins to funnel moisture into southeast Wyoming and
western Nebraska. As this trough is quick-moving and only briefly
turns winds northerly, kept PoPs mainly in the 30-40 percent range
outside of the Snowy, Sierra Madre, and Laramie mountains, where
PoPs are closer to 60-80 percent. The highest confidence right now
is in accumulating snowfall in the mountains with at least colder
temperatures in the plains and lower elevations. If the plains are
to receive any precipitation, it will likely be between Wednesday
afternoon and Thursday afternoon; falling as snow in south central
Wyoming and starting as rain east of the Laramie Range,
transitioning to snow overnight Wednesday.
&&
.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 424 PM MST Sat Feb 17 2024
Ridging aloft will move overhead tonight, then westerly flow
aloft will develop on Sunday ahead of an approaching shortwave
trough.
Skies will be clear overnight, with ceilings near 15000 feet
developing Sunday morning and afternoon. Winds will gust to
35 knots for the Wyoming terminals after 15Z Sunday.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...High Wind Warning from 5 AM to 9 PM MST Sunday for WYZ101-107.
High Wind Warning from 3 AM Sunday to 8 AM MST Monday for
WYZ106.
High Wind Warning from 5 AM Sunday to 8 AM MST Monday for
WYZ110.
High Wind Warning from 11 AM Sunday to 8 AM MST Monday for
WYZ116-117.
High Wind Watch from Sunday afternoon through late Sunday
night for WYZ118.
NE...None.
&&
$$
SHORT TERM...MB
LONG TERM...LEG
AVIATION...RUBIN
Area Forecast Discussion
National Weather Service Grand Rapids MI
629 PM EST Sat Feb 17 2024
.KEY MESSAGES...
- Strong wind gusts tonight close call for a Wind Advisory
- Above normal temperatures through Thursday
- Colder with light snow showers late Friday/Saturday
&&
.DISCUSSION...
Issued at 156 PM EST Sat Feb 17 2024
- Strong wind gusts tonight close call for a Wind Advisory
A 35 to 40 knot low level jet arrives tonight. As this feature
moves in overnight, the mixing height deepens. How strong the
winds get will largely be determined by how deep we mix. Looking
upstream in the Upper Plains gusts have been mostly in the 30
knot range this afternoon. As this low level jet moves into the
CWA tonight and the mixing height deepens, the surface winds
will increase. Based on ensemble mean wind gust guidance from
multiple models and the deterministic runs, we will fall short
of a Wind Advisory. The 18z HRRR suggests the 40 knot winds will
stay just offshore. However, it will not take much additional
mixing to reach impactful levels and we will need to monitor
trends closely through the evening. In addition, stronger
pressure falls are occurring in WI ahead of this system so an
isallobaric component to this system exists. These types of
systems sometimes lead to higher winds than expected. We will
highlight a very windy night for the region in the forecasts,
along with the potential for isolated power outages in any
messaging/posts. The Hazardous Weather Outlook was updated
earlier to reflect this potential. Lakeshore locations should
see peak gusts in the 40 to 45 mph range with inland locations
seeing gusts around 40 mph.
- Above normal temperatures through Thursday
Temps will average around ten to fifteen degrees above normal for
this time of year from Monday through Thursday. This is the result
of a split flow upper level pattern that will keep colder air
bottled up well to our north. Very tranquil weather is also forecast
through Thursday with little more than a few light rain showers
Wednesday.
- Colder with light snow showers late Friday/Saturday
A clipper system will move in from the northwest late Friday and
Saturday and bring potential for light snow showers. Some lake
effect snow showers are expected in the wake of that system as a
colder airmass briefly moves in as the polar jet briefly dips
further south. Temps will return to near normal for this time of
year Friday through next weekend.
&&
.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 628 PM EST Sat Feb 17 2024
Area of thin stratus with ceilings around 3000 feet AGL and tops
blo 4000 feet are across much of Lower Michigan this evening.
There is some local IFR in BLSN at MKG as winds gust over 25
knots. Otherwise, VFR conditions will prevail much of the
overnight and on Sunday.
Southwest winds will gust over 25 knots tonight then go west on
Sunday morning with some gusts to 30 knots possible. WInds will
go northwest Sunday afternoon and decrease to 10 to 20 knots by
late afternoon.
&&
.MARINE...
Issued at 156 PM EST Sat Feb 17 2024
The arrival of a 35 to 40 knot low level jet tonight will
strengthen the winds over the nearshore waters. Ensemble wind
guidance supports a period of gales. This will be a short
duration event with small craft conditions expected to quickly
take over later tonight/early Sunday as the low level jet shifts
south of the zones.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...Small Craft Advisory until 7 PM EST this evening for
LMZ844>849.
Gale Warning until 5 AM EST Sunday for LMZ844>849.
&&
$$
DISCUSSION...MJS/Laurens
AVIATION...Ostuno
MARINE...MJS
Area Forecast Discussion
National Weather Service Las Vegas NV
802 PM PST Sat Feb 17 2024
.SYNOPSIS...The first of two Pacific systems will brush the east
slopes of the southern Sierra with light snowfall tonight while
dry and mild weather continues across the rest of our area. A
second stronger and wetter system will bring unsettled weather
conditions to the area early next week with significant snow
accumulations likely in the Sierra. The storm will also bring
strong winds to the area on Monday along with widespread
rain and mountain snow Monday through Wednesday. The system
moves east of the area late next week.
&&
.UPDATE...Surface observations/radar showing light rain falling
along the western Sierra foothills with light snow in the higher
elevations. Most of the precipitation with the shortwave moving
through northern California tonight will fall in the southern Sierra
with very light rain, if any at all for the Owens Valley. Some light
precipitation may skip east across the central Nevada mountains
tonight as well. Latest HRRR indicates precipitation will probably
be done by daybreak Sunday.
A stronger system over the eastern Pacific this evening will usher
in a long duration precipitation event for primarily California
Sunday-Wednesday. Lighter QPF values will occur across the remainder
of southern Nevada, eastern California and northwest Arizona in the
middle of the week. Winter Storm headlines for the southern Sierra
and White/Inyo Mountains of Inyo County go into effect late Sunday
afternoon continuing through Wednesday. No additional headlines are
needed at this time so no update to the forecast is needed.
&&
.PREV DISCUSSION...147 PM PST Sat Feb 17 2024
.DISCUSSION...Sunday through Wednesday.
For the southern Sierra...light snow showers are possible on
Sunday before the next stronger and wetter system brings moderate
to heavy snow to the crest and eastern Sierra slopes Sunday night
through Wednesday morning. A Winter Storm Warning is in effect
for the Sierra from 4 pm Sunday through 10 am Wednesday. By early
Wednesday, 18-24 inches of new snow are forecast for Aspendell
with 2-4 feet above 9000 feet and locally up to 5 or 6 feet at
the peaks. Winds Sunday night and Monday could gust as high as 50
mph leading to low visibility in unprotected areas due to blowing
snow.
In the White Mountains of Inyo County...a Winter Storm Warning is
in effect for elevations above 8000 feet from 4 pm Sunday through
10 am Wednesday. Storm total snow accumulations of 8-16 inches are
possible, mostly at elevations where impacts will be limited. 1-2
inch snow accumulations are forecast on Highway 168 across
Westgard Pass which could create minor travel difficulties due to
slick roadways.
Regarding the Spring Mountains...the current forecast calls for
4-8 inches of new snow between 4 am Monday and 4 pm Wednesday with
half of that forecast to fall late Tuesday night into early
Wednesday. Although winter weather conditions are possible at
times above 6500-7000 feet on all 3 days, accumulated snow
amounts requiring a headline are not expected until perhaps
Tuesday night. Given the current forecast would only justify an
advisory and the fact there is high uncertainty in both timing and
potential snow amounts, opted not to issue any headlines this far
out from the event.
There are 2 other aspects to this storm...3-day accumulated rain
amounts below the snow level and strong winds on Monday. Forecast
rain amounts across the area 10 pm Wednesday include 0.50-1.00
inches in the Owens Valley, 0.25-0.50 inches in areas west and
north of Las Vegas, generally less than 0.25 inches in areas south
and east of Las Vegas with much of this area including much of
the Las Vegas Valley seeing less than a tenth of an inch. For
winds, we are expecting widespread gusts of 25-35 mph on Monday
with gusts 40-50 mph possible in the higher elevations. More
localized areas across parts of south central Nevada could see
gusts at or exceeding 40 mph which may warrant a wind hazard
product at some point but will not be issued yet.
Thursday and Friday...the weather pattern is forecast to deamplify
with a return to dry and mild weather conditions across the region.
&&
.AVIATION...For Harry Reid...Light winds following typical diurnal
trends will continue into Sunday morning. Winds will break from the
normal trends Sunday afternoon when southwest winds approaching
10kts develop ahead of the approaching Pacific storm system. There
is still some uncertainty on the timing of the wind changes, but
current guidance suggests it will be between 20Z and 23Z. Occasional
mid and high-level clouds with bases AOA 15kft AGL will move across
the area through the TAF period.
For the rest of southern Nevada, northwest Arizona and southeast
California...Light winds following typical diurnal trends are
expected across the Las Vegas Valley through Sunday morning. In the
Owens Valley, including KBIH, breezy south-southeast winds of 20-
25kts continue through the afternoon. Winds decrease overnight as
moisture from the approaching Pacific Storm spills over the
Sierra, resulting in a few showers and reduced CIGs around 7kft
AGL. The chance of showers ends by tomorrow morning, but
increasing southerly winds and the chance of additional showers
return Sunday afternoon. Winds remain light at KDAG through the
evening before west to southwest winds to 15kts develop by
tomorrow morning. Breezy northerly winds in the lower Colorado
River Valley today will become light overnight and then increase
to 10-20kts out of the south on Sunday. Outside the Owens Valley,
most areas will see occasional mid and high-level clouds with
bases AOA 15kft AGL through the TAF period.
&&
.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report
any significant weather or impacts according to standard operating
procedures.
&&
$$
UPDATE...Pierce
DISCUSSION...Salmen
AVIATION...Planz
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