Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 12/01/22

Area Forecast Discussion...UPDATED

National Weather Service Aberdeen SD

 518 PM CST Wed Nov 30 2022

.UPDATE...
Issued at 517 PM CST Wed Nov 30 2022

The forecast remains on track this evening. No major changes are
planned.

&&

.SHORT TERM...(This Evening through Thursday Night)
Issued at 223 PM CST Wed Nov 30 2022

As of 21Z, the CWA is seeing a mostly sunny sky with temperatures
in the teens and 20s. Breezy northwesterly winds continue
impacting the eastern half of the CWA with a steady decrease
across the western half. The winds should become light and
variable later this evening before shifting to the southeast
overnight. Models continue showing a strong LLJ developing
especially over the eastern half of the CWA after 6Z. Wind gusts
may exceed 45 mph at times over the higher terrain areas of the
Sisseton Hills. The increasing winds should cause temperatures to
become steady or slowly rise after midnight.

High temperatures on Thursday are somewhat challenging. Depending of
deterministic model used, 925 mb temps may warm into the single
digits above zero C, or as the NAM indicates, around 0C. The NAM, as
well as the 12 and 18Z HRRR show a fairly good inversion over the
eastern half of the CWA, keeping temperatures on the cooler side of
NBM guidance. With some snow cover south of the CWA, along the
potential for snow melt and southerly winds, the added moisture in
the boundary layer may limit heating on Thursday. Also, the lack of
southwesterly or westerly winds at the surface is a limiting factor
as well. With warm temps at 850 mb, along with a southwesterly wind
component at 850 mb and the lack of snow cover over the CWA, will
continue with warmer temperatures over much of the CWA. Did go with
NBM 50th over the eastern half of the CWA due to poor mixing winds.
An approaching area of low pressure and associated frontal
boundaries will keep the environment well mixed Thursday night,
keeping temperatures in the teens and 20s.

.LONG TERM...(Friday through Wednesday)
Issued at 223 PM CST Wed Nov 30 2022

The biggest weather concerns between Friday and next Wednesday is
over what portion of the CWA will a light accumulation of snow occur
on Friday while strong northwest winds increase, along with how cold
it could be Monday through Wednesday of next week.

When the period opens, deterministic and ensemble camps of models
all showcase a low pressure system churning across the northern
plains states. Rather strong low level (700hpa and below) fronto-
forcing potential seen in the models, associated with the cold fropa
progged to occur on Friday, but synoptic scale lift still only seems
to be topping out around 10 microbars. The latest trend seems to be
pushing the potential for measurable snow further north into North
Dakota (NBM/EC Ensemble Mean probability of an inch or more of
snow). That said, there is still the potential for some of the
northern tier counties of the CWA to pick up a light accumulation
(generally an inch or less) of snow between 9AM CST and 9PM CST on
Friday. Regarding the cold fropa, once the wind shifts to the
northwest on/along the Prairie Coteau and starts increasing in
speed/gustiness, there could be the potential for a little bit of
additional terrain-forced light snow enhancement (perhaps upwards of
2 inches?) there on the Coteau Friday afternoon/evening. Wind
speeds/gusts could be tickling advisory strength by late Friday
afternoon and on into the overnight hours. Running things through
the blowing snow model for Friday/Friday night only yields "patchy
blowing snow" mention for now.

Generally speaking, once this Friday system clears the region Friday
night, the CWA will be influenced for much of the forecast period by
northwest flow. The northern branch of a developing split flow
regime will dictate if and when smaller transient areas of low
pressure will dive south-southeastward over the Dakotas, influencing
the region`s sensible weather conditions. Right now, PoPs in the
extended (beyond Friday) are non-measurable (less than 15%), but
would not be shocked if between Saturday and Wednesday, the CWA sees
a couple quick shots of heavy flurries or light (accumulating?)
snow. More than that, deterministic and ensemble output today
supports the idea that after a potential brief temperature recovery
back to near normal by the end of the weekend, another strong arctic
cold frontal passage will sweep through the CWA early next week,
setting the stage for more much below normal temperature
conditions.

&&

.AVIATION...(For the 00Z TAFS through 00Z Thursday Evening)
Issued at 517 PM CST Wed Nov 30 2022

Terminals KABR,KATY,KPIR,KMBG

VFR conditions are expected through the next 24 hours. South to
southeast winds will increase tonight.

&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&

$$

UPDATE...Wise
SHORT TERM...SD
LONG TERM...Dorn
AVIATION...Wise



Area Forecast Discussion

National Weather Service Charleston SC

 857 PM EST Wed Nov 30 2022

.SYNOPSIS...
High pressure will build in across the region through Friday. A
front will then shift into the area Saturday and Saturday
night, and could linger in the vicinity into early next week.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
No major changes were made for the late evening update.

Satellite, surface observations and RAP instability analysis at
showed the cold front was located roughly along a Moncks
Corner-Walterboro-Denmark-Claxton-Baxley line at 01/0145z. A
little fog has developed just ahead of the front, but it will
not last too long as surface winds will pick up quickly with
FROPA.

The boundary is showing a classic bending pattern in the lee of
the Southern Appalachians, typical when fronts interacts with
the higher terrain of the Black Mountains of southwestern North
Carolina, including Mount Mitchell. The deepest moisture has
pushed offshore and with it any risk for measurable rainfall.
The front will clear the coast roughly in the 10-11 PM timeframe
with drier and cooler conditions advecting in behind it. Once
the front pushes through, expect rapid clearing to occur with
clear skies prevailing overnight. Lows will range from the mid-
upper 30s well inland to the upper 40s/near 50 at the beaches.

Lake Winds: Winds on Lake Moultrie are expected to surge a bit
overnight as low-level cold air advection interacts with water
temperatures near 60. Winds in the mixed layer look to fall just
short of Lake Wind Advisory criteria, but a solid 15-20 kt along
with waves 1-2 ft are expected.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
Thursday and Thursday night: High pressure will continue
building into the region Thursday, becoming centered near the
Virginia Tidewater region Thursday night. The airmass will be
very dry, with precipitable water values of a quarter of an inch
or less through the day. The main story will be the
significantly cooler temperatures. Highs are forecast to only
reach the mid to upper 50s, with some low 60s possible along and
south of I-16. Such temperatures would be on the order of 10
degrees below normal for early December. Also, northeast winds
will be elevated due to the tight pressure gradient, making it
feel even cooler. Overnight, lows will be chilly with low to mid
30s across the far inland counties, ranging to the low to mid
40s along the coast.

Friday through Saturday: The center of the high will shift out
over the northwest Atlantic as a subtle coastal trough sits just
offshore. As the high moves away, the low-level flow pattern
will be easterly and southeasterly through Friday night, then
southerly ahead of an approaching front on Saturday. Friday is
currently expected to be dry, though with the coastal trough
nearby we can`t completely rule out some weak shower activity
along the coast. For Saturday, it appears that nearly all of the
precipitation will remain upstream along the front and any that
approaches from the northwest late in the day will be on a
distinct diminishing trend. Temperatures will moderate
significantly through the period with highs increasing well into
the 60s Friday and then back into the 70s Saturday.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
The front will drift into the area Saturday night and become
oriented west to east. How far south across the area the front
pushes is in question and then it appears as though it will
linger int he vicinity into early next week before lifting back
northward as a front. This injects some uncertainty into the
forecast regarding rain chances because depending on the
position of the front, the axis of rainfall could shift
significantly north or south. For now it looks like the best
chance of rain will come Sunday night into Monday before the
front starts lifting northward taking with it the best forcing
for precip. For now this is where we have the best rain chances,
though they are held in the 20-30 percent range. As the
positioning of the front and its movement come more into focus,
rain chances could end up being higher with better confidence in
the timing. Otherwise, temperatures will generally be above
normal, especially once the front lifts north of the area.

&&

.AVIATION /02Z THURSDAY THROUGH MONDAY/...
KCHS/KJZI/KSAV: VFR. The cold front will push through the
terminals roughly 02-03z with a wind shift to the northwest and
eventually north.

Extended Aviation Outlook: Mostly VFR.

&&

.MARINE...
Tonight: Northwest then north winds will pick up quickly behind
the cold front has it pushes across the waters over the next few
hours. Winds will peak 20-25 kt with gusts to 30 kt all coastal
legs with 15-20 kt in the Charleston Harbor. Frequent gusts will
will be very close to advisory levels for a few hours overnight,
so a Small Craft Advisory has been posed for the Charleston Harbor
until 4 AM. Seas will build 4-6 ft nearshore waters and 5-7 ft
over the Georgia offshore water where Small Craft Advisories
remain posted.

Thursday through Monday: Thursday will begin with a solid
northeast surge underway as high pressure build into the region.
Small Craft Advisories are already in effect for all waters
outside of Charleston Harbor, and we should see a solid 20-25
knots of wind with gusts to 30 kt. Seas will increase to 4-6
feet across the nearshore waters and 6-7 feet for the outer
waters. One thing to watch will be winds in Charleston Harbor,
especially Thursday morning. Wind gusts will be near 25 knots
for several hours and a Small Craft Advisory could be needed.
Conditions will gradually improve through Thursday night as
winds and seas diminish. Winds will then turn more southerly and
then southwesterly into the weekend before a front drifts in
from the north late in the weekend. Overall, once the advisory
conditions come to an end Thursday and Thursday night, winds and
seas should remain well below advisory thresholds into early
next week.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
MARINE...Small Craft Advisory until 4 AM EST Thursday for AMZ330.
     Small Craft Advisory from midnight tonight to 4 PM EST
     Thursday for AMZ350-352.
     Small Craft Advisory from midnight tonight to 7 PM EST
     Thursday for AMZ354.
     Small Craft Advisory from midnight tonight to 1 PM EST Friday
     for AMZ374.

&&

$$



Area Forecast Discussion

National Weather Service Goodland KS

 411 PM MST Wed Nov 30 2022

.SHORT TERM...(This evening through Thursday)
Issued at 143 PM MST Wed Nov 30 2022

This evening through the overnight hours a weak disturbance aloft is
expected to travel across the Rockies and over the area,
strengthening the lee trough along the Front Range. This and a
tightening pressure gradient will bring an increase in sky cover and
winds during the overnight hours. The winds are expected to be out
of the southeast to south at 10-25 mph and gusts up to 40 mph
through sunrise tomorrow. The strongest winds are anticipated to be
along and south of I-70. Temperatures tonight will be in the upper
teens to mid 20s with wind chills in the upper single digits to
upper teens.

On Thursday another upper disturbance will sit over the area while
the lee trough broadens across the Plains ahead of Friday`s strong
cold front. Temperatures warm up nicely tomorrow with highs in the
mid 50s to lower 60s. Thursday, southerly to southwesterly winds are
expected to be around 10-20 mph with gusts up of 25-30 mph possible.
Overnight lows will be in the mid 20s to upper 30s tomorrow night.

.LONG TERM...(Friday through Wednesday)
Issued at 250 PM MST Wed Nov 30 2022

Strong gusty winds on Friday will cause concern for increased fire
weather and blowing dust threats.

Model guidance for Friday is beginning to align, although there is
still a decent amount of variance. The GFS and NAM are both
suggesting that the surface low pressure system and associated cold
front will move across the Goodland CWA earlier than previously
expected. The cold front will cross the Tri-State area from the
northwest to the southeast, and is expected to enter Yuma county in
Colorado during the late morning hours. The FROPA will quickly cross
the CWA and is expected to be clear of the area by the evening.

With the earlier passage of the cold front, temperatures will top
out in the 50s and 60s, and minimum RH values will be at least in
the upper teens. This will help decrease the fire weather risk.
However, continuing dry conditions have provided ample fuels to burn
and winds will work to increase the fire weather threat. Sustained
winds of 20 to 30 kts and gusts up to 44 kts are expected throughout
the CWA. Strong winds are expected before and after the cold front,
and the wind shift it will cause. If any fires were to start, the
wind could quickly spread them and the change in wind directions
(from the southwest becoming northwestern) with the FROPA could make
firefighting operations challenging.

Blowing dust is also a concern on Friday. The GFS and RAP are
showing 0-2 km lapse rates over 9 C/km, 2-2.5 km lapse rates of 3-6
C/km, and 0.5-1 km winds over 40 kts around 18-21Z on Friday. These
conditions paired with strong winds at the surface could produce
blowing dust. There is a concern that the FROPA could create a wall
of dust, but at this time confidence is not high that this will
occur.

If the cold front were to move through the area later in the day,
temperatures could climb into the 60s and 70s which would lower RH
values into the mid teens. If this were to happen, the risk for fire
weather danger would increase substantially. Another implication of
the later timing of the FROPA would be a lower chance of a wall of
dust, but areas of patchy blowing dust would be more likely.

After the cold front has passed, Friday night will cool into the low
to mid teens and wind chills will drop into the lower and middle
single digits by Saturday morning. Saturday through Monday, a
warming trend will be the big news due to a high pressure system
moving over the southern portion of the CWA. Monday`s temperatures
will max out in the upper 40s and mid 50s, a 5 to 10 degree
difference from Saturday`s high temperatures. Overnight low
temperatures will be in the lower to mid 20s for these nights.

Monday afternoon will see a weak cold front pass through the area
and cause the winds to come from the north again, cooling the Tri-
State area into the mid and upper teens for Tuesday and Wednesday
morning. This will also cap Tuesday`s high temperatures in the lower
to mid 40s. Thankfully, this shift should be short lived and
Wednesday will warm back up into the mid 40s, about normal for this
time of year.

&&

.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 410 PM MST Wed Nov 30 2022

Only aviation concern will be LLWS tonight at both KGLD and KMCK
as a southwesterly nocturnal low level jet develops. Otherwise,
VFR expected to prevail at both terminals.

&&

.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&

$$

SHORT TERM...KMK
LONG TERM...CA
AVIATION...024



Area Forecast Discussion

National Weather Service Pocatello ID

 239 PM MST Wed Nov 30 2022

.SHORT TERM (Tonight - Friday AM)...
A period of active winter weather is underway across eastern Idaho
this afternoon and this will continue for the next 48 hours or so.
A strong area of low pressure off of British Columbia and its
associated moisture will overspread the region over the next few
days bringing widespread snow and gusty winds. Starting with the
snow, the next few days will bring FEET of snow to the Wood River
Valley north to Stanley and north of Ashton through Island Park
with up to around 2 feet of snow in the valleys and amounts up to
4 feet of snow in the mountains. Highest totals will be across
southern upslope favored areas of the Sawtooths, Western Smokys,
and Centennials. Totals across the eastern and southeastern
Highlands won`t be nearly as high but still likely to reach around
a foot, or a bit more. Winter storm warnings continue for these
areas and we`re expecting SIGNIFICANT impacts in these areas not
only from snow, but gusty winds creating widespread
blowing/drifting snow making travel extremely difficult in these
areas.

Elsewhere, Winter Weather Advisories are now in effect for the
rest of the area, including into the Snake Plain and eastern
Magic Valley. In those areas, accumulations are a bit more
difficult to forecast as southerly winds will likely allow for
temps to warm above freezing for a brief period, perhaps allowing
for a rain/snow mix during the afternoon hours. That being said,
hi-res model soundings show this layer as being very shallow or
non-existent (depending on your model of choice) so that
complicates matters a bit. Nevertheless, by late evening as the
front moves through, confidence is high that precip will be all
snow at this point and it will likely come down quite quickly with
the front. In addition to this, winds will be a concern as the
snow is falling creating some very difficult driving conditions
around much of the area and this will likely be during the evening
commute. For these reasons feel an advisory is the best course of
action for this event although totals will be on the low side
especially as you head into the eastern Magic Valley. Totals will
be higher however as you head towards AF and Pocatello and
especially from Blackfoot north on I-15. Totals across the Upper
Snake Plain, mainly from Rexburg into St. Anthony could flirt with
Winter Storm Warning criteria so an upgrade in this zone could be
needed on subsequent forecasts although Idaho Falls likely falls
in the 4-6" range for this event. In short, things are still a bit
in flux in spots but outside of the Snake Plain and Magic Valley,
there`s good confidence in meeting advisory criteria.

Briefly discussed the wind concern already but late Thursday and
into Friday appears to be the time of biggest concern with winds.
Current wind forecast relies heavily on the NBM 90th percentile
and NBM 4.1 which has winds gusting in the 25-35 mph range for
much of the region with higher gusts expected in the higher
terrain and in the more wind-prone locations like near Yale and
Idahome.

Bottom line is this, expect a prolonged period of high-impact
winter weather across the region but the most significant impacts
will be focused across the Central Mountains and eastern
Highlands. Even if the current snow forecasts in the Snake Plain
don`t quite materialize as they`re currently forecast, winds will
still create winter weather impacts with the snow that does fall
and the snow that is currently on the ground across the region.
McKaughan

.LONG TERM (Friday through next Wednesday)...
This week`s weather system will come to an end on Friday, but
we`ll be dealing with some lingering snow east of Interstate 15
through Friday afternoon. We`ll also be dealing with some gusty
winds throughout the day Friday in a post-cold frontal regime.
Weather will settle down Friday night with models depicting a
transient ridge shift through the area on Saturday. Deterministic
models indicate an upper low developing off the OR/CA coast
Saturday, pushing onshore on Sunday. As the low moves inland,
moisture will advect into Idaho from the south. Ensemble clusters
are still showing some uncertainty on when the upper low will fill
and eject eastward, a factor that will ultimately drive QPF for
the region. The 00Z EFI continues to maintain a relatively low-
impact weather system with no extreme snowfall, but anomalously
cooler temperatures. Quieter weather is indicated by most models
by Tuesday afternoon, but the region will remain at the backside
of a broad upper trough through Wednesday. Hinsberger

&&

.AVIATION...
Moisture continues to stream across southeast Idaho with snow
ongoing as SUN and DIJ. SUN remains below airfield minimums to
start off the TAF period, but NBM and HRRR guidance shows
improvements there by mid afternoon. DIJ has seen some bouts of
IFR visibility this morning, and NBM shows this to continue for a
couple more hours, but the terminal was VFR at TAF issuance. IDA
may see some periods of IFR visibility this afternoon with a band
of snow moving through, but PIH, IDA, and BYI should have a dry,
downslope wind through tonight. Conditions will again deteriorate
tonight as another batch of moisture is transported into the
region mostly impacting SUN and DIJ. Hinsberger


&&

.PIH WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from 5 AM Thursday to 11 AM MST Friday
for IDZ051-052-068-070.

Winter Weather Advisory from 5 AM Thursday to 5 PM MST Friday
for IDZ053>059-061-062.

Winter Storm Warning from 5 AM Thursday to 5 PM MST Friday for
IDZ060-063>065.

Winter Storm Warning until 5 PM MST Friday for IDZ066.

Winter Storm Warning until 11 AM MST Friday for IDZ067-069.

Winter Storm Warning until 5 AM MST Friday for IDZ071>075.

&&

$$