Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/26/22
AREA FORECAST DISCUSSION
National Weather Service Bismarck ND
950 PM CDT Tue Oct 25 2022
.UPDATE...
Issued at 950 PM CDT Tue Oct 25 2022
Updates were made to the cloud cover again to match with current
satellite trends. The possibility of fog still exists in the
northwest, both the RAP and HRRR have high RH after 06z.
UPDATE Issued at 640 PM CDT Tue Oct 25 2022
Just some minor updates to the cloud cover based on the current
satellite trends. The RAP is still showing the possibility of fog
in the northwest with RH near 100 percent around midnight.
&&
.SHORT TERM...(This Evening through Wednesday)
Issued at 138 PM CDT Tue Oct 25 2022
The main forecast issue in the short term period will be sky cover
and temperatures tonight.
Currently, weak high pressure is situated over the forecast area.
An exiting shortwave that brought some light snow to the northern
tier counties this morning is exiting the area. Additional light
reflectivities capable of producing a sprinkle or flurry were
located over southeast Saskatchewan into southern Manitoba. This
could rotate into northern ND late this afternoon or this evening
and produce a brief sprinkle/flurry but only trace amounts are
expected with no impacts.
Warm advection will overspread the CWA from west to east tonight
with a few bands of clouds expected to linger across mainly
northern ND, but at times may extend into central or even southern
ND. The warm advection and clouds would indicate mild overnight
lows (relatively speaking) but with our recent snow there remains
a pretty sizable area of snowcover over western ND, with the
deepest snowpack from around the Interstate and northward. With
high pressure over the area, expect winds to diminish this evening
and think we could see temperatures drop pretty quick over the
snowpack. However, to complicate things, some lower stratus and
fog remains over portions of the snowpack. Thus at this time it
seems fruitless to try and guess temperatures here. We did go
ahead and blend the cooler previous guidance with our given NBM
guidance to lean a bit toward cooler temperatures over the
snowpack. Expect the evening and overnight shifts will need to
revisit at least a few times. We also kept a mention of patchy fog
over and around the snowpack. The RAP is indicating fog
developing in the northwest later this evening, but on occasion is
a little overdone. The HRRR is depicting very little fog here at
this time. Wednesday looks to bring a mix of sun and clouds with
slightly warmer temperatures most areas.
.LONG TERM...(Wednesday Night through Tuesday)
Issued at 138 PM CDT Tue Oct 25 2022
Generally a quiet extended period looks to be in store, with a quasi-
zonal flow over the northern tier states through the weekend. Early
in the period the upper flow splits over the northern and central
Rockies, with most energy sliding well to our south. However, a bit
of energy remains in the northern stream and we may see a bit of
light precipitation brush our southeast CWA Wednesday night into
Thursday morning. Thereafter, impulses will be coming off the
Pacific and across the Northern Rockies with little moisture
reaching the Northern Plains. We could see some increasing high
clouds later in the extended period but after the Wednesday
night/Thursday system, our NBM PoP forecast is dry through the
weekend and into early next week. NBM Ensemble spreads later this
week and through the weekend remain fairly narrow indicating good
confidence in the given ranges. Normals for late October are in
the lower 50s for highs and mid to upper 20s for lows. For the
most part, it looks like we should be around normal to a little
above normal through the extended period for both highs and lows.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday Evening)
Issued at 950 PM CDT Tue Oct 25 2022
MVFR clouds remain across the east, affecting KJMS, these will
move out by 09z. Lower clouds between 3-10 kft will remain
through Wednesday morning for the rest of the area. The clouds
will mostly clear out by early morning with VFR conditions through
the period. Patchy fog is possible in the northwest, affect KXWA,
was not confident enough to put lower visibilities in the TAFs
yet. Timing could be around 06z. Winds will be light overnight
then gusting up to 15kts from the south Wednesday afternoon.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...Smith
SHORT TERM...TWH
LONG TERM...TWH
AVIATION...Smith
Area Forecast Discussion
National Weather Service Birmingham AL
748 PM CDT Tue Oct 25 2022
...New SHORT TERM, AVIATION...
.SHORT TERM...
(Tonight through Wednesday)
Issued at 720 PM CDT TUE OCT 25 2022
A cold front was located just southeast of the I-59 corridor this
evening. The front will continue eastward and clear the area after
midnight. Showers and a few thunderstorms were ongoing ahead of
the front from near Anniston to Montgomery. Shear remains high
over the area but instabilities were limited and lapse rates were
poor. Do not expect any uptick in this activity as it exits the
area after midnight. Gusty Winds will slowly subside through the
evening. The chances of any gusts near 35 mph is rather low and
will cancel whats left of the Wind Advisory.
75
Previous short-term discussion:
(This evening through Wednesday)
Issued at 141 PM CDT TUE OCT 25 2022
A potent upper low was located over the Ozarks in Northern
Arkansas within a negative tilted trough over the Mid South
Region. Surface low pressure has become more organized over
Southeast Missouri with a cold front extending from Southwest of
St. Louis south through Central Mississippi. Regional radar
composites with satellite animations indicate the convection has
been strengthening gradually with time over the past few hours as
the activity is moving east through an area with temperatures in
the lower 70s with dew points in the upper 60s. Surface-based
instability persists in a fairly narrow swath along and just
ahead of the convective line from eastern Mississippi to near the
AL/MS state line per 17z RAP mesoanalysis data. The highest shear
and best forcing is positioned across Northeast Mississippi and
Northwest Alabama at this writing. Through mid afternoon, expect
the line of storms to continue moving east into West-Central and
Northwest Alabama from 1 to 3 pm.
A tornado watch is currently being issued for the western portion
of the area, generally near Interstate 65 and west through 7 pm
tonight.
Tonight.
Showers with some thunderstorms will continue to move east,
affecting much of the eastern portion of the area tonight. The
overall intensity of the line is expected to gradually weaken with
time with damaging winds being the primary concern with bows
within the line of storms. There will remain a tornado risk with
embedded circulations, QLCS, within the line of storms. Winds will
gradually weaken overnight from the southwest to west at 6-12 mph.
Lows will range from the mid 40s northwest to the low 50s
southeast.
Wednesday.
Dry conditions will return areawide on Wednesday but cloud cover
will likely linger through the morning hours then clearing
entirely from southwest to northeast through the daytime hours.
Winds will be from the west to northwest at 6-12 mph. Highs will
range from the mid 60s north to around 70 far southeast.
05
&&
.LONG TERM...
((Wednesday night through next Monday)
Issued at 318 PM CDT TUE OCT 25 2022
Models have trended slightly wetter for the system next weekend,
and trended rain changes and qpf upward. Otherwise, no changes
needed.
14
Previous long-term discussion:
(Wednesday night through Monday)
Issued at 308 AM CDT TUE OCT 25 2022
Flow aloft becomes southwesterly through the rest of the week
ahead of the next trough digging into the Southern High Plains in
this progressive split flow pattern. At the surface, winds will
be out of the east courtesy of a strong high pressure center
centered over Quebec, though the associated CAD wedge should stay
northeast of the area. The easterly winds will keep dew points and
RH values from crashing as much as in recent days as well as low
temperatures to a certain extent. Expect pleasant conditions with
a good bit of sunshine.
The southern stream trough will eventually close off into a slow-
moving upper low that will impact the forecast area over the
weekend. Deep layer SSW flow ahead of the upper low will
eventually result in moist isentropic lift and widespread rainfall
at some point during the weekend, while a weak surface low lifts
northward over the Lower Mississippi Valley. The deterministic GFS
trended slower towards the deterministic ECMWF with the area
remaining mostly dry Saturday afternoon. However, am leery of
buying this trend as these are just 2 of 80 ensemble members, and
the ensemble means and many ensemble members of the EPS and GEFS
are quicker than the deterministic runs. Therefore, leaned heavily
on the ensemble members for timing of the higher PoPs but have
capped values at 50% for now. A warm front may lift northward into
our southern counties with enough instability for a few
thunderstorms. 0-6 km bulk shear values are only around 30-35 kts,
so severe storms are not expected at this time.
32/Davis
&&
.AVIATION...
(00Z TAFS)
Issued at 720 PM CDT TUE OCT 25 2022
A cold front was moving through Central Alabama as of this
writing. It was approaching BHM/EET as winds have turned to the
west at TCL. Showers and a few thunderstorms were ahead of the
front from near ANB to MGM. The convection will affect
ANB/ASN/MGM/TOI for another hour or so before exiting the area.
There may be a brief period of MVFR ceilings near this convection.
A wrap around moisture area will follow behind the front and also
may produce some MVFR ceilings for the northern sites. Gusty
southerly winds will veer to west and then north as high pressure
moves in behind the front.
75
&&
.FIRE WEATHER...
Drier conditions return for Wednesday and Thursday, but with
minimum RH values above critical thresholds. Low level winds swing
around to the north Wednesday and northeast Thursday.
&&
.PRELIMINARY POINT TEMPS/POPS...
Gadsden 45 64 42 72 / 90 0 0 0
Anniston 47 64 44 73 / 90 0 0 0
Birmingham 47 64 46 72 / 50 0 0 0
Tuscaloosa 46 68 46 72 / 10 0 0 0
Calera 46 65 47 73 / 50 0 0 0
Auburn 49 67 47 73 / 90 0 0 0
Montgomery 48 69 45 75 / 80 0 0 0
Troy 50 69 45 76 / 90 0 0 0
&&
.BMX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...75
LONG TERM....14
AVIATION...75
Area Forecast Discussion
National Weather Service Denver/Boulder CO
901 PM MDT Tue Oct 25 2022
.UPDATE...
Issued at 900 PM MDT Tue Oct 25 2022
There is a little disturbance approaching in the mostly westerly
flow aloft and the next shortwave isn`t far behind that, coming on
shore over the Pacific Northwest. Skies are mostly cloudy to
overcast across most of northeast Colorado. There are some light
snow showers around the peaks of the Front Range which will
persist through the night. Radar suggests there may be a few very
light rain showers on the eastern plains as well, but it`s harder
to say. The forecast is performing well with only minor updates
this evening.
&&
.SHORT TERM...(This evening through Wednesday)
Issued at 254 PM MDT Tue Oct 25 2022
Satellite and RAP mesoanalysis show that... not a whole lot has
changed since the morning AFD. Colorado remains underneath
westerly flow aloft, with moisture increasing slightly over the
past several hours. As a result, there`s been a slight uptick in
snow showers across the northern mountains, particularly the Park
and Medicine Bow Ranges, where webcams and SNOTEL data have
suggested at least some light accumulations have already occurred.
Snow is expected to continue across the higher terrain overnight,
gradually shifting south this evening. There should be a slight
increase in coverage and intensity towards daybreak Wednesday as
QG ascent increases, with a couple inches of snow expected. A cold
front will also push across the plains overnight, with mid-level
frontogenesis (and its accompanying lift) along with some weak
upslope flow might be enough for a few rain and snow showers over
the plains, though temperatures will likely be too warm to support
any accumulation below 7000 feet.
Wednesday will see snow showers continuing across the mountains.
The flow aloft will shift more to the west-southwest ahead of an
approaching trough, so most of the snow should be focused on the
Park and Gore ranges early in the day. Across the plains, a few
light showers may continue along the Wyoming border, but otherwise
it should be mostly quiet.
Precipitation should increase across the mountains yet again by
late Wednesday afternoon as PVA associated with the approaching
shortwave should lead to a brief period of enhanced rates. For
more details on the snow Wednesday night into Thursday keep
reading the section below...
.LONG TERM...(Wednesday night through Tuesday)
Issued at 254 PM MDT Tue Oct 25 2022
There`s reasonable agreement on the trough moving across Colorado
Wednesday night into Thursday. Minor differences on QPF and
temperature do affect snow prospects for Denver, as most of the
models are struggling to get cold enough while most ECMWF ensemble
members do produce an inch of snow. It`s only a degree or two so
it`s hard to pick a winner at this point. With the QG lift sliding
southeast from the northern mountains and the surge of upslope,
this could be a scenario where there`s a definite focus of
precipitation sliding south along the foothills from Boulder to
Douglas county with much less elsewhere. We`ve generally accepted
the NBM QPF but raised PoPs and bumped up the snow ratio a bit for
a bit more snow in the mountains and a little accumulation where
it does snow along the foothills.
The lift moves out and drier air, subsidence, and warming aloft
come in quick behind it later Thursday. This should set up a
cooler night for Denver and Boulder with a more definite freeze
for most spots Friday morning. Temperatures should pop back up to
near 60 in Denver for Friday through Sunday, with valley areas
lagging a little in cold pools for at least the first day. A
shortwave passing north of us Sunday could bring some clouds, then
we go to a bit more flow from the west or southwest for early next
week that should provide some wind in the wind prone areas. Faster
solutions would bring some moisture in the southwest flow by
Tuesday, but probably not enough for mountain snow yet. There
could be a couple of marginal fire weather days in the early to
middle part of next week ahead of the next trough when it looks
dry, warm, and breezy.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 533 PM MDT Tue Oct 25 2022
Expect VFR conditions to persist through the rest of today, then
ceilings to lower this evening and overnight with potential for
ILS ceilings at about 4 to 6 kft into the morning. There is a
slight chance of very light rain or snow showers tonight but
confidence is low and impact would be minimal. Ceilings should
rise in the morning. Winds have come around north-northeasterly at
KDEN and KAPA this afternoon, while breezy westerly winds persist
at KBJC and and look to continue into the evening. Winds should
come around southeasterly tonight and in the morning, then turn
back northeasterly for the afternoon.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...EJD
SHORT TERM...Hiris
LONG TERM...Gimmestad
AVIATION...EJD
Area Forecast Discussion
National Weather Service Columbia SC
724 PM EDT Tue Oct 25 2022
.SYNOPSIS...
A front will cross into the region late tonight, with scattered
showers possible towards morning. Dry weather is expected
behind the front through Friday. Chances of rain increase late
in the weekend when another upper disturbance approaches from
the west.
&&
.NEAR TERM /THROUGH TONIGHT/...
The upper level cutoff low centered over southeastern Missouri
will continue lifting off to the northeast overnight. The trough
axis south of the cutoff will help to push a prefrontal trough
into our region late tonight. Moisture increases ahead of this
surface trough after midnight, helping to push some showers towards
the cwa. Best dynamics remain well north, and mainly expecting
a line of scattered showers with an isolated thunderstorm possible.
QPF amounts still look to remain light. The best timing for the
line entering the western cwa still appears to be centered around
09z, with the bulk of the weakening activity then exiting off
to the east by 12z. With an increase in clouds cover and winds
later tonight, temperatures will drop into the lower to mid 50s.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
Closed upper low will track NE along the Ohio Valley and open
and shift into New England/E CAN Wednesday, with most upper
dynamics staying to our north. Latest CAMs in good agreement
that weak surface front and associated scattered light shower
activity will move into the CSRA by daybreak, through the
central forecast area (FA) during the morning to midday hours,
and push east of our FA during the afternoon, while the shower
activity is expected to gradually diminish.
Weak upper ridging to shift back into the region Thursday. The
air mass behind the weak front is not cool with a surface high
center emerging from N Mex/TX and shifting NE and merging with a
Canadian high center to the north. The main upper flow will
keep the coolest air well to our north. Drier air will be
shifting into the region behind the boundary with PW generally
averaging around 0.75 inch Thu. Expect winds to veer behind the
surface boundary passage late Wed/Wed nt, and become NE by Thu.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
Upper low to cut off over the S Rockies/West TX and shift east
to the Lower Miss Valley Fri/Sat with resultant surface low
developing near the TX/LA coast. Main zonal upper flow across
the northern tier of states/S CAN. Confluent flow aloft to
intensify the surface high center to our NE as it shifts east
across E CAN and settles over New England. The closed low is
progged to open and shift NE into the Midwest Sun/Mon along with
the surface low, followed by upper energy expected to track
from the SW US east across TX Monday and towards our region
Tuesday. Meanwhile, the surface high will ridge down the eastern
seaboard. Latest information indicates best isentropic
lift/moisture transport for our region will be Sat nt/Sun/Sun
nt, with hybrid cold air damming regime setting up at the
surface. Due to the wedge, max temps are expected to trend down
considerably for Sun/Mon. The wedge and associated low clouds
and cool max temps are expected to be slow to erode with only
weak surface high pressure, and SW flow aloft, over the region
Mon/Tue. It appears good downslope flow to scour out the low
cloudiness does not occur until late Tue/Tue nt into Wed behind
the passage of an upper disturbance.
&&
.AVIATION /23Z TUESDAY THROUGH SUNDAY/...
High confidence in VFR conditions through 06z or so then
possible MVFR ceiling restrictions Wednesday morning.
Upper system and associated cold front to our west will push
eastward tonight and cross the region on Wednesday morning.
Winds have been calm to light and variable and will remain so
through the evening. After midnight the pressure gradient will
increase a bit and southerly winds should develop less than 5
knots ahead of the prefrontal trough. Clouds will also be
increasing and lowering through the predawn hours. The latest
HRRR and NBM suggesting fog development in the coastal plain
after 06z. The probability of visibility restrictions at the
area terminals should remain quite low as mid level clouds
increase along with increased winds in the boundary layer.
A broken line of showers is expected to push across the region
during the 11z-16z time frame. Some MVFR cigs may accompany this
feature along with some isolated showers. Behind the trough,
winds will pick up from the west-southwest and become gusty into
the afternoon. Showers not expected to lead to visibility
restrictions.
EXTENDED AVIATION OUTLOOK...No significant impacts to aviation
expected through Thursday but chances for restrictions with low
clouds could increase starting Thursday night into Friday and
impact the weekend.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
&&
$$
Area Forecast Discussion
National Weather Service Lincoln IL
844 PM CDT Tue Oct 25 2022
.SYNOPSIS...
Issued at 308 PM CDT Tue Oct 25 2022
Additional rounds of scattered showers and isolated thunderstorms
are expected to continue through Tuesday night as a low pressure
system moves through the region. Breezy northwesterly winds are
expected tonight. The breezy winds continue on Wednesday, with
clearing skies and temperatures in the upper 50s. Thursday and
Friday look seasonable, with lighter winds and high temperatures
in the mid 50s to near 60. After tonight, the next chance of
rainfall is late Saturday night into Sunday.
&&
.UPDATE...
Issued at 838 PM CDT Tue Oct 25 2022
As of around 8pm this evening, surface low pressure was analyzed
to be centered near Mattoon. Scattered showers are ongoing across
much of the area, but most numerous near the Illinois River
Valley where a deformation axis is in place. An additional quarter
to three quarters of an inch of rain is likely overnight near the
Illinois River Valley with a quarter inch or less expected
elsewhere. Forcing within this feature will shift northeast
through the evening and tonight with precip ending from the
southwest overnight, but not completely exiting the forecast area
until around daybreak Wednesday morning.
&&
.SHORT TERM...(This evening through Wednesday)
ISSUED AT 308 PM CDT Tue Oct 25 2022
Satellite imagery shows a low pressures system continuing to lift
northeast through the Ozarks. The front across our area continues
to shift slightly east, located between I-55 and I-57 as of
2pm/19z. Widespread rain continues across the CWA, as the warm
conveyor belt of the approaching low pressure system pivots
through the area. RAP mesoanalysis shows low but non-zero MUCAPE
across eastern IL, where a few embedded t-storms are ongoing/will
be possible this afternoon with the warm conveyor belt precip.
A precip free corridor appears likely to pivot through the area
this afternoon/evening, then additional rain chances occur as the
low moves northeast through the area tonight. Ahead of the sfc
low, clearer skies have allowed a small zone of surface-based
instability to develop over southern MO, and t-storms have erupted
within that zone over the last hour (to the south of Farmington,
MO). This zone will pivot through the southeastern half of our CWA
this evening, but by the time it does so diurnal heating will be
diminishing, so while t-storms may persist the chances of stronger
storms is low. Another frontogenesis zone oriented north-south
immediately behind the low is producing another band of rainfall
that will move west to east through the area overnight, bringing
precip chances to an end as it departs before sunrise on
Wednesday. Additional rainfall amounts from the precip that occurs
as the low pressure moves through the area tonight will generally
be around 0.25-0.50", although locally higher amounts are
possible with any t-storms.
With the low lifting off to the northeast on Wednesday and sfc
high pressure centered over MO/IA, brisk northerly winds will
keep a chill in the air for much of the day as temps only reach
the upper 50s. As the sfc high shifts east towards the area, winds
gradually become lighter into the afternoon. Aside from some
lingering cloud cover in eastern IL Wed AM, mostly sunny skies
will prevail.
.LONG TERM...(Wednesday night through Tuesday)
ISSUED AT 308 PM CDT Tue Oct 25 2022
For the start of the long term period, a few benign, seasonable
days are expected. By Wed night, sfc high pressure should be
positioned just north of the area, and the combination of clear
skies/light winds will result in the coolest night of the week,
with lows dropping into the upper 30s. That high pressure quickly
shifts off towards the Great Lakes on Thurs and strengthens as it
does. Thurs and Fri both look seasonable, with highs in the mid
50s to near 60F, and lows near 40. Forecast soundings suggest
rather widespread high cloud cover on Thurs, becoming less
extensive on Fri.
The next chance of rain will be courtesy of a closed upper low
moving slowly through the southern Plains Fri into the weekend.
Model guidance remains inconsistent in the precip timing with this
wave. Precip could move in as early as late Sat eve, but the
chances increase into Sun and diminish into Monday. Based on the
track of the wave, precip chances decrease from southeast to
northwest across the CWA. QPF amounts aren`t expected to be as
heavy with this wave, with the latest probabilistic data from the
NBM showing a 35% chance of exceeding 0.25" and less than a 5%
chance of exceeding 1". Despite this wave passing through the
region, no major temperature changes are expected through the
extended forecast. Highs will generally be in the upper 50s to mid
60s with lows in the low 40s. An early look at Halloween night
suggests temperatures near 50F and minimal impacts from wind or
precip, although if the upper wave trends slower some light precip
could linger into Halloween night.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 620 PM CDT Tue Oct 25 2022
Low pressure is near Effingham this hour and will lift northeast
across east central Illinois this evening. Scattered showers and
an isolated storm or two will continue through the rest of the
evening across central Illinois, then will taper off from the
west overnight. Meanwhile, gusty north to northwest winds will set
up behind the low but gusts are expected to diminish overnight
into Wednesday morning. IFR/MVFR ceilings will also accompany the
low and will also improve back to VFR late tonight into Wednesday
morning.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Deubelbeiss
SYNOPSIS...Erwin
SHORT TERM...Erwin
LONG TERM...Erwin
AVIATION...Deubelbeiss
Area Forecast Discussion
National Weather Service Pocatello ID
857 PM MDT Tue Oct 25 2022
.UPDATE...
Updated forecast to lower overnight lows as temps have fallen
quickly this evening under clear skies. Expect clouds to arrive
overnight which should help insulate. Temps are a little closer to
the NBM forecast based on evening trends and timing the cloud
cover.
13
&&
.PREV DISCUSSION... /issued 238 PM MDT Tue Oct 25 2022/
SHORT TERM...Today through Wednesday. We`ll stay mostly dry
through the rest of today aside from some light precipitation
lingering in the eastern highlands with breezy conditions through
the Magic valley and Snake plain with gusts up to about 30mph
until 8-9PM. Our next system starts to move in around midnight as
snow begins in the Sawtooths and spreads south and eastward
through the central mountains and across the rest of the state
during the early morning hours. Models are hinting at the
potential for a band of a rain/snow mix during the morning moving
from west to east which could impact parts of I-86 and I-15 from
7- 10AM. Temperatures will be hanging right around freezing or
just above, which could limit snow and give more rain south of
Blackfoot. Temperatures will be a couple of degrees cooler north
of Blackfoot, which would lend themselves towards snow more than
rain. Winds are going to be breezy at the time, but are expected
to pick up post-front, which would help limit snow squall
potential, but it is still worth watching and keeping in mind for
the morning commute. While the ingredients are there, the
uncertainty lies with whether or not they all come together at the
right time. The NAM and HRRR bring in another band of snow after
4PM that will impact areas of the Snake Plain and eastern
highlands, staying mainly north and east of the Pocatello area,
though the HRRR wants to skirt the eastern edge of Pocatello. Most
of the snow, aside from some light showers in the higher
elevations of the eastern highlands comes to an end shortly after
midnight. The highest snow totals will generally be 4-6 inches in
the Sawtooths, Big Holes, and Bear River Range with the rest of
the mountains seeing 2-4 inches. Snow totals in the Snake Plain
and Magic Valley will be below an inch with the NBM 4.1 WSUP
viewer showing only a 15-25 percent chance of an inch of snow. The
wind is also going to be a player in the forecast. Went with
gusts from the 90th percentile of NBM 4.1 and still had to bump
them up slightly and am getting gusts between 30-35mph and
sustained winds between 25- 30mph which is just below wind
advisory criteria. That said, some localized areas within the
south hills and Magic Valley have a 30-40 percent chance of seeing
isolated gusts closer to 40-45mph. Winds will be strongest
between noon and 8PM on Wednesday before they begin to back off.
Our weather begins to quiet down as we head into Thursday morning.
AMM
LONG TERM...Thursday through Tuesday. Upper ridge builds into the
region behind departing shortwave Wednesday. Temperatures remain
cold, but slowly moderate Friday into Saturday. Next Pacific trough
slides south along Alaskan/BC coast by Saturday, with weak shortwave
flattening ridge ahead of it by late Saturday. From there, solutions
begin to deviate so there is still quite a bit of uncertainty
through remainder of the period. Most solutions favor precipitation
onset by Sunday afternoon across the central mountains, but slow to
spread east. Ensemble clusters still show quite a split between a
very shallow ridge and a flat trough across the region Sunday, but
nearly all give way to the Pacific trough moving into the PacNW or
across the Northern Rockies by Monday. NBM has trended slower as
well, holding off on bulk of precipitation until Monday/Tuesday.
From there, solutions remain consistent with valley rain/snow,
mountain snow, and breezy to windy conditions. DMH
AVIATION...Weak late fall afternoon shallow convection still
lingers across the eastern highlands impacting KDIJ this afternoon,
but remainder of terminals remain VFR. Next system drops into the
region late this evening, spreading light precipitation west to east
through Wednesday morning associated with frontal boundary. Ceilings
drop fairly rapidly with precipitation onset, and could temporarily
drop to IFR/LIFR with any convective enhancement of bands associated
with front. Precipitation should be all snow at KSUN/KDIJ, mixed at
KIDA, potential mix at KPIH, and all rain at KBYI. Gusty winds
associated with the front, and then in post-frontal environment
Wednesday afternoon, could gust well over 30kts. DMH
&&
.PIH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Area Forecast Discussion
National Weather Service Pueblo CO
251 PM MDT Tue Oct 25 2022
.SHORT TERM...(This evening through Wednesday)
Issued at 250 PM MDT Tue Oct 25 2022
Key Messages:
1) Slightly cooler for our Wednesday with snow beginning in the
mountains and breezy winds elsewhere.
Currently..
Satellite imagery depicts fairly zonal flow, with increasing cloud
cover coming in from our northwest, and widespread mountain wave
cloud formations over Colorado as well. Temperatures have warmed
into the low to mid 60s for most of the plains, and winds are
following normal diurnal patterns in most areas. A trough is
deepening over the Pacific Northwest.
Tonight and Tomorrow..
An upper trough pushing across the northern plains drops a weak cold
frontal boundary across eastern Colorado overnight. This feature
doesn`t look to bring too many changes, but we could see some
briefly breezy northerly winds as it passes, particularly north of
Highway 50. Daytime high temperatures will be a couple of degrees
cooler tomorrow as well, with most of the plains warming into the
60s, mountain valleys getting into the 50s, and higher terrain
locations staying in the 40s. Upslope flow sets up over our central
mountains, where snow showers are expected to begin as early as 9pm
this evening.
As the Pacific Northwest trough and associated low pressure system
push into the Northern Rockies tomorrow, our flow aloft will turn
from mostly zonal to southwesterly throughout the day. This will
bring continued orographic upslope flow and plenty of moisture to
our central mountains, where light to moderate snowfall is expected
throughout the day. Snow is forecast to spread southeastward, into
the La Garitas and San Juans by early morning and possibly even into
the western facing slopes of the Wet Mountains by early afternoon as
well. As the system plunges southward into the four corners region
by tomorrow afternoon, the pressure gradient will tighten overhead.
This will bring gusty southwesterly winds to the San Luis Valley and
breezy southerly winds to our eastern plains as well. Relative
humidity values behind tonight`s frontal boundary keep us too moist
to warrant fire weather headlines at this time, but winds could gust
up to 30 mph tomorrow afternoon.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 250 PM MDT Tue Oct 25 2022
Key messages:
1) A deepening major shortwave trough is going to impact the region
with snow (mainly over mountains), windy conditions, and colder
temperatures Wednesday night through Friday morning.
2) Ridge will build in with a warning trend and drier conditions
throughout the weekend and into early next week.
Detailed discussion:
Wednesday night through Friday...
Deterministic models are in relatively close agreement of a
deepening of a major shortwave trough with a positively tilted axis
propagating in over the region by late Wednesday night though
Thursday. The position of the associated closed low at the 500 mb
level is generally close, with the exception of the Canadian model,
with being over the southeastern portion of Idaho. The Canadian is
the outlier with having the position being over the western portion
of Wyoming. This keeps the progression slightly ahead of the other
models and allows for a better chance of precip over the plains if
this verifies. Otherwise, the progression has only slight deviation
between the models with the low moving nearly over the Four Corners
area as the shortwave continues to deepen. This will result in the
mountains getting most of the precip with this storm system, as the
U/L divergence is centered over the Continental Divide area.
The cold front associated with this system looks to move over the
CWA around between 3 and 6 AM during the morning on Thursday. The
high resolution models such as the HRRR has the front arriving as
early as 2 AM over the most northern portion of El Paso County.
There could be some snow showers with accumulating snow of possibly
an inch or more over the Palmer Divide and northern I-25 corridor in
El Paso County as it does, which may result in some tricky travel
conditions during the morning commute for this area as it does. Due
to upsloping as the winds become northeasterly, there could be some
locally heavy snowfall amounts for the eastern facing slopes of the
Wet Mountains and the Sangre de Cristo Mountains. With some upper
level diffluence over the central mountains, there could be enough
PVA to allow for sufficient instability and some thunder possible
with the snow showers, especially over the Sawatch Range during the
afternoon on Thursday.
Northerly winds will continue to increase and become rather blustery
throughout the day over the plains, especially over eastern El Paso
County, where the winds could gust close to High Wind Warning
criteria for a few hours. With snow showers likely over the Palmer
Divide, this may produce occasional blowing snow with near white out
conditions in this area. These winds will continue to come down by
later in the evening as the gradient relaxes. As the U/L low
continues to progress further to the southeast over central New
Mexico, the mid level flow at the 700 mb level is going to turn to
the northeast, with the strongest winds being reflected in the
ECMWF. Given this, there could be some locally heavier snowfall
amounts over the southern Sangre de Cristo Mountains by later in the
day on Thursday.
The colder air advection should keep temperatures mainly in the 40s
over most of the plains, and perhaps only making it into the 50s
over the far eastern plains. As a whole, temperatures will be
anywhere between 10 to 20 degrees below the seasonal average across
the CWA. Upsloping should keep most areas overcast along the I-25
corridor. The snow level will drop to as low as around 5300 feet
over northern El Paso County. Some of the rain/snow showers will
continue over the southeastern plains into the early morning hours
on Friday due to wrap around moisture, although most of the CWA
should clear out by then as the low pressure system continues to
move out of the area. Due to sufficient radiational cooling because
of this, there will be very cold temperatures on Thursday night
through Friday morning, with some locations in the higher mountain
valleys dropping into the single digits and perhaps even below zero.
There will also be a slight chance of some freezing fog in some of
the higher valleys and the San Luis Valley. Friday will be slightly
warmer as surface winds out of the north weaken and switch back to a
southeasterly direction by later in the day.
Saturday through Tuesday...
As a ridge continues to build back in over the region throughout the
weekend, temperatures will return back to the seasonal average with
drier conditions expected to last into early next week under high
pressure. Looking past the forecast period into the later part of
next week, there are some indications with ensemble data of the EPS
and GEFS alike of the ridge breaking down and a longwave trough
beginning to move in over the region and possibly influence the
region with colder and unsettled weather. -Stewey
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 250 PM MDT Tue Oct 25 2022
VFR conditions are expected at all three terminals, KCOS, KPUB, and
KALS for the next 24 hours. At KCOS and KPUB, a weak frontal
boundary will increase northerly winds overnight tonight and help to
increase mid-level cloud coverage as well, especially at KCOS. At
KALS, winds will become northerly and eventually variable overnight
tonight. A strong pressure gradient will increase southwesterly
winds tomorrow in the San Luis Valley, bringing gusts over 20kt to
the terminal tomorrow afternoon.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...EHR
LONG TERM...STEWARD
AVIATION...EHR