Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/17/23
Area Forecast Discussion
National Weather Service Cheyenne WY
752 PM MST Mon Jan 16 2023
.UPDATE...
Issued at 750 PM MST Mon Jan 16 2023
The forecast largely looks on track this evening, but made a few
minor changes with this update. Satellite observations show an
area of fog/low clouds extending across Niobrara county and into
northern Sioux/Dawes counties. Hires models are trending a little
more aggressive with fog coverage in the Nebraska panhandle and
east central Wyoming tonight into Tuesday morning, so expanded and
smoothed the region where the forecast will mention patchy fog. RH
is mostly 85%+ along and east of a Sidney to Lusk line at this
hour, and should continue to increase as temperatures cool. Lack
of clear upslope winds and only one observation showing visibility
under 1/4 mile at this time precludes a Dense Fog Advisory, but
will need to monitor through the night if fog becomes more
widespread. Still though more areas warranted a mention of fog in
the forecast.
Looking ahead to the main snow event tomorrow night into
Wednesday, earlier model outliers are starting to come into
slightly better agreement, boosting forecast confidence. The HRRR
(which at 18z was a major outlier with a northerly storm track),
and the GEFS/GFS (slightly south of model consensus at 12z) have
shifted closer to the NBM/ECMWF consensus scenario with their 00z
and 18z runs respectively.
&&
.SHORT TERM...(Late this afternoon through Wednesday night)
Issued at 225 PM MST Mon Jan 16 2023
The upper level system that produced the precipitation yesterday
was located over IA. An extensive blanket of low/mid clouds lingered
further west over the Dakotas and much of NE. The next Pacific upper
level storm was progressing eastward across northern CA and western
NV, with leading edge of mid/high clouds spreading into WY/CO. A
weak surface trough was situated along the WY Laramie Range, with
a decent pressure gradient just to the west. A band of subsidence
and weak mountain wave activity kicked up west- southwest winds
earlier this morning with brief gusts of 55-60 MPH near Arlington
and Buford. The winds have since decreased with the relaxing
gradient. Early afternoon temperatures were closer to seasonal
normals for mid-January with lower 30s to lower 40s.
The forecast challenges during the next 24 to 48 hours will focus
on the placement and timing of moderate to heavy snow impacting
the I-80 Corridor and points to the north and east with the passage
of the next Pacific storm system.
During the past 24 hours, models have come into slightly better
agreement of a more northerly track of the upper level/surface
low, which has resulted in higher QPF/storm total snow projections
across southern and eastern portions of the CWA. The 18Z WPCGuide
increased QPF about 0.10-0.20 inch and snow accumulations of 1-2
inches. Snow ratios have likewise increased to 12-14:1. The 15Z
NCEP ensemble means rose 1-2 inches from the previous 6 hours. At
this time, forecast snow totals are heaviest along the I-80 Corridor
from eastern Laramie County to Cheyenne County with 6 to 9 inches.
With increasing confidence and WFO coordination with LBF and BOU,
upgraded the Winter Storm Watch to a Warning. Outside the
Warning, amounts of 4 to 6 inches are possible for central Laramie
County, with 4 to 8 inches over portions of northern and central
NE Panhandle. These areas are included in a Winter Storm Watch.
Additional watches and advisories may be issued west including the
South Laramie Range/Foothills and north along/east of I-25
including Platte and Goshen Counties as there are indications the
storm system may be slower to exit. The caveat in the Winter Storm
products is the uncertainty in the track of this storm which
could impact where the heaviest snowfall occurs.
One saving grace with this storm system will be the lack of strong
winds. Right now, north to northwest winds on the backside of the
low could gust as high as 30 MPH, which would produce patchy blowing
snow. The snow tapers off from west to east late Wednesday afternoon
and evening.
Temperatures will continue to trend cooler Tuesday through Wednesday
night. Expect highs in the 30s, except 20s mountains on Tuesday.
Highs Wednesday will range from the mid 20s to lower 30s, except
teens to lower 20s mountains on Wednesday. Lows tonight and Tuesday
night will range from the upper teens to mid 20s, with upper single
digits and teens Wednesday night.
.LONG TERM...(Thursday through Monday)
Issued at 225 PM MST Mon Jan 16 2023
KEY MESSAGES:
1) Snow chances have decreased further Thursday night into Friday
morning, staying mainly west of the Laramie Range Thursday evening.
Then, along and south of the Interstate-80 corridor early Friday
morning and afternoon. Snow accumulations near an inch possible.
2) Snow chances in the Snowy and Sierra Madre Ranges mainly Friday
and late Saturday night through Monday. Additional accumulations 4
to 8 inches possible with the greatest accumulation expected Sunday
and Monday.
3) Marginal High Wind chances Thursday and Sunday. Wind gusts 50 to
60+ mph possible.
DISCUSSION: The long term period is still looking colder with
marginal snowfall and high wind concerns. The High Wind chances have
increased slightly Thursday as global models are showing the Tuesday-
Wednesday winter storm pushing out a bit slower than guidance was
previously showing. This slower push maintains the pressure gradient
across portions of southeast Wyoming. High Wind chances remain
confined to the wind-prone areas of southeast Wyoming. The snow
chances have dropped a little bit more for Thursday into Friday.
PoPs are sitting between 10 and 20 percent. Long Range Global models
are showing the low dropping south west of the Rockies before
developing more near the Four Corners and ejecting eastward. The
current trajectory brings it too far south to cause too many impacts
to southeast Wyoming and the Nebraska panhandle. The primary snow
chances are Thursday evening through Friday afternoon. Temperatures
in southeast Wyoming are quite chilly with high temperatures mainly
in low 20s to low 30s. The Nebraska panhandle is a few degrees
warmer with highs in the upper 20s to 30s. Valley temperatures may
plummet even lower than what is currently forecast if skies clear
overnight, especially in areas with a fresh snowpack.
Saturday, the weather briefly lulls as a weak ridge positions itself
on top of southeast Wyoming and the Nebraska panhandle before the
next trough is forecast to move in Sunday. Kept PoPs near the same
as the previous shift, 30 to 40 percent due to the GFS and ECMWF
continuing to show very different solutions. There is still not any
real confidence in what the impacts with this winter storm will or
will not turn out to be, but the active pattern continues!
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 429 PM MST Mon Jan 16 2023
An active weather pattern is beginning to take shape with respect
to the aviation forecast. Expect VFR for KLAR and KCYS through
midday Tuesday. KRWL will see MVFR to IFR conditions beginning at
8Z overnight, and extending through a majority of Tuesday.
The difficult forecast overnight into Tuesday will reside with the
timing for the NE Panhandle terminals. The HREF and HRRR are
aggressive with low CIGs and VIS remaining overnight for all
terminals in the Panhandle. Expect the terminals at KAIA and KCDR
quickly transition to IFR/LIFR near 4Z/5Z this evening, with KBFF
and KSNY likely approaching IFR/LIFR near 10Z early Tuesday.
Before then, expect MVFR to become prevalent.
&&
.FIRE WEATHER...
Issued at 225 PM MST Mon Jan 16 2023
No fire weather concerns are anticipated this week due to recent
and expected snowfall, below normal temperatures, and elevated
daytime humidities. Outside of stronger winds this afternoon and
Thursday, winds will be non-critical.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...Winter Storm Watch from Tuesday afternoon through Wednesday
afternoon for WYZ118.
Winter Storm Warning from 5 PM Tuesday to 5 PM MST Wednesday for
WYZ119.
NE...Winter Storm Watch from Tuesday afternoon through Wednesday
afternoon for NEZ003-019>021.
Winter Storm Warning from 5 PM Tuesday to 5 PM MST Wednesday for
NEZ054-055.
&&
$$
UPDATE...MN
SHORT TERM...MAJ
LONG TERM...LK
AVIATION...BW
FIRE WEATHER...MAJ
Area Forecast Discussion
National Weather Service Dodge City KS
513 PM CST Mon Jan 16 2023
...UPDATE TO AVIATION...
.SHORT TERM...(This evening through Tuesday night)
Issued at 344 PM CST Mon Jan 16 2023
Western Kansas was in between two storm systems today, yielding
quiet weather in the form of a clear sky, westerly surface wind
around 10 mph (15 to 20mph up toward Hays), and pleasant mid-Winter
afternoon temperatures in the mid to upper 50s. Tonight, winds will
be light and variable in between storms, but we will be watching a
weak cold front push south by early Tuesday morning, which will
bring an increase in northeast wind along with higher relative
humidity supporting low stratus and areas of fog. We have introduced
some areas of fog in to the forecast for areas generally along and
north of Highway 96, but there is some fairly strong signal of dense
fog development with rather high HREF probabilities of 40 to 60
percent for one-quarter mile visibility... particularly in the 13-
17Z time frame. The next shift will need to continue monitoring this
possibility for possible dense fog inclusion and perhaps a headline.
As the next mid-latitude cyclone develops and approaches the
southern Colorado Rockies Tuesday, surface cyclogenesis will
increase across southeastern Colorado, and surface winds across our
southwest Kansas region will become increasingly easterly component
as a result. Warm conveyor belt (WCB) precipitation will begin to
develop first across the western Texas and Oklahoma Panhandles as
early as 00Z Wednesday with the north-south orientation of the rain
axis expanding in length as it moves out across southwest Kansas.
The latest 18Z HRRR model run appears to have a pretty good
representation of the hourly composite reflectivity and 1-hr QPF
field for this type of a system in the WCB airstream, and the POP
grids reflect this to a certain degree. The dominant north-south
axis of WCB rain will advance eastward fairly quickly late evening
into the overnight Tuesday with surface temperatures generally from
the mid 30s north to the mid 40s south. We will have to watch the
extreme northwestern portions of our forecast area as temperatures
will be closer to 32F and probability of a rain-snow mix greater up
in that area. There does not appear to be much of a risk for any
freezing rain given absence of a pre-existing shallow cold airmass
ahead of this storm, thankfully.
By daybreak Wednesday, the WCB rain shield will likely be out of our
forecast area with the exception of maybe Stafford down to Barber
County, but even down there, the dry intrusion air stream will be
punching in quickly from the southwest, effectively clearing things
out. Cold advection behind the low later in the day Wednesday will
certainly be noticeable with strong winds 25 to 35 mph for several
hours during the day Wednesday, but no arctic air will be involved
behind this storm, so afternoon temperatures Wednesday should still
reach upper 30s to mid 40s most areas.
.LONG TERM...(Wednesday through Monday)
Issued at 344 PM CST Mon Jan 16 2023
A fairly active pattern will continue into the Long Term period. Two
more storms appear to be poised for the Central and/or Southern
Plains Saturday through Monday. Latest global model consensus is the
Saturday storm will track from New Mexico into West Texas/Texas
Panhandle with the greatest precipitation signal to the south of
Southwest Kansas. The second of the two storm will dig south down
the Rockies, which will have a much larger area of colder, Canadian
airmass involved, along with stronger north wind. Of all three of
these storms, it would appear the last one (Sunday Night-Monday)
could pose the greatest risk for hazardous weather in the form of
wind-blown snow, colder temperatures, and stronger wind. There is
plenty of time to keep watching the evolution in the global spectral
models and their trends for both these storms Saturday-Monday, so
keep checking back for updates.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 455 PM CST Mon Jan 16 2023
VFR conditions will prevail in vicinity of all TAF sites through late
tonight. Low level stratus developing behind a cold front shifting slowly
south across Nebraska, is expected to spread southward into northern
Kansas late overnight, potentially reaching as far south as KHYS generally
after 09-11Z, and possibly KGCK and KDDC toward daybreak Tuesday morning.
MVFR/IFR cigs can be expected at the terminals affected. Light and
variable winds are likely to continue through early Tuesday morning
despite a weak cold front dipping slowly southward through western/central
Kansas before stalling out somewhere in vicinity of the Oklahoma border
Tuesday morning.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 28 48 32 43 / 0 0 60 30
GCK 25 46 27 38 / 0 0 70 40
EHA 30 55 28 42 / 0 10 40 20
LBL 26 52 28 43 / 0 10 50 10
HYS 27 44 29 37 / 0 0 80 70
P28 33 55 38 52 / 0 0 50 20
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Umscheid
LONG TERM...Umscheid
AVIATION...JJohnson
Area Forecast Discussion
National Weather Service El Paso Tx/Santa Teresa NM
503 PM MST Mon Jan 16 2023
...New AVIATION...
.SYNOPSIS...
Issued at 126 PM MST Mon Jan 16 2023
Below normal temperatures will continue across the Borderland
through the upcoming weekend. Breezy to windy conditions will also
prevail most days. Mountain snow showers will continue through
Tuesday with a break expected Wednesday and Thursday. The next
system will bring a chance for some precip to northern areas
Friday night into Saturday. A quick break Sunday with another
storm system possible for Monday.
&&
.SHORT TERM...
(This evening through Tuesday)
Issued at 126 PM MST Mon Jan 16 2023
Our active pattern continues as we remain beneath the jet of a broad
long-wave trough covering much of the Lower 48. Within this trough
are a couple of disturbances that will affect our weather in the
short-term. The first is affecting us now. It will exit late this
afternoon or evening with a lull (but not a total break) expected
tonight before the second system starts to affect us in the morning.
The second system will exit Wednesday morning. Let`s talk about
impacts:
Precipitation: lowland rain and mountain snows will continue through
the whole period. Best chances for precip will remain west of the
Continental Divide although models are underdoing how much precip is
making it east of the Divide. For example, neither the HRRR nor NAM
Nest are showing the current (12pm) band of rain running from the
Bootheel all the way into the Sacs. There will probably be a lull
this evening and overnight for most locations as this first system
departs and then showers should increase areawide tomorrow morning
though isolated to scattered showers cannot be ruled out overnight
for all areas. As far as snow is concerned, it feels a bit like
chasing a moving target. What seems the most certain is snow level
with levels keeping above 7500 feet and with accumulation really
occurring above 8000 feet. These levels will begin to drop later
Tuesday afternoon. For amounts, guidance has a poor handle on totals
as liquid QPF fields vary from hardly anything to over 3.5" in the
NAM Nest. I will go out on a limb and say the NAM Nest is wrong.
Thus, largely based precip amounts and subsequent snow totals on the
NBM 4.1 QPF (liquid) mean, ignoring the operational NBM, which shows
excessive, warning-criteria snowfall totals in our mountains. This
technique yields an additional 2 to 6" of snow in the Gila and Sacs,
which seems reasonable although a few spots could easily see an inch
or two more than that. Snow will not be continuous, but to avoid
confusing messaging, I decided to keep the winter weather advisory
for the Gila and Sacs ongoing with its expiration at midnight
Tuesday night.
Wind: With the persistent jet overhead, there will be persistent lee
troughing though the surface low will have a tendency to deepen,
shift east and weaken, with a new low forming behind it. This will
keep a tight gradient over Southern NM and W. Texas. The surface low
today will be relatively weak, but gradients look to be tight enough
to bring breezy conditions to part of the area. With that said,
winds are not as strong as expected for where the current wind
advisory exists likely because the rain is keeping the airmass more
stable than forecast. I will therefore cancel it. Winds will subside
overnight as the first surface low shifts east, weakening gradients
some in addition to the decoupling of the atmosphere. As mentioned,
a new surface low will form in its wake, and this one looks to be
deeper with a tighter gradient. H700 flow will range 35 to 45 knots
with H850 flow ranging 20 to 30 knots. With the rain and clouds and
what looks to be a reinforcement of the cool airmass already in
place, surface winds will be slow to respond to the pressure falls
and increase in winds aloft. We will be breezy, but we look to
remain below advisory criteria. The exception could be the Sacs
where the CAMs show stronger winds. With all of the current
headlines and changes in headlines in place plus the marginal
forecast, I will let later shifts take another look and respond
accordingly.
&&
.LONG TERM...
(Tuesday night through next Sunday)
Issued at 126 PM MST Mon Jan 16 2023
The Borderland will continue to be under an active weather pattern
through the long term which will lead to below normal temperatures
and occasional precip chances. Starting Tuesday night, the current
system moving out of the Great Basin will be moving out of the
area to the northeast, but a last piece of energy on the back side
could keep a few snow showers going over the mountains. Elsewhere
clouds will be on the decrease with breezy to windy conditions
continuing through Wednesday. There will be a deep surface low
around the OK Panhandle with a tighter, better oriented gradient
across the region than the last couple days. Winds aloft will be
less than yesterday, so think speeds will be windy and possibly
some areas reaching low end advisory over southern zones. High
pressure quickly builds in Wed night and with drier air moving in
as well, should see a fairly cold morning Thu with the lowlands
into the 20s. Thu should have the lightest daytime winds of the
week with sunshine, however, temperatures will still struggle to
get above the mid 50s anywhere.
Another upper low will be moving out of the southern Great Basin
Fri and start to affect the western zones late in the day Friday.
West winds will increase to 10-25 mph. Models differ on the
strength and placement of this feature as it moves through. The
GFS is quicker and further north than the slower, further south
EC. Ensemble means of the GFS and EC are similar and a nice
compromise which brings the system through west-central NM and
would likely lead to precip over the Gila down to maybe the
Lordsburg area and then north through Sierra and northern Otero
counties. Most of the precip could fall as snow except in the
lowest elevations where it could start as rain and possibly mix
with or change over to snow if the moisture lingers long enough.
This system will drop temperatures about 5 to 10 degrees for Sat.
Northwest flow behind this system will bring in some colder, dry
air for Sunday. Sunday morning could be the coldest morning of the
week with some teens possible in the lowlands if winds drop off
overnight.
Another system starts to dive out of the Pacific Northwest for
early next week. Some big differences in the handling of this
energy among the models with the GFS taking energy SW and cutting
off a low over southern NV while the EC is now diving the energy
straight down the west side of the Rockies and bringing some cold
air into the region with the main cutoff over the Dakotas. Again
the ensemble means of the two models are in good agreement and
looks to support some kind of cutoff developing around AZ. Went
with temps a little colder than the NBM which was closer to the
MEX temps than the EC with possibly some light precip moving into
the area. This system will need to be watched as it has the
potential to have some cold air associated with it and is a
pattern supporting snow across the CWA.
&&
.AVIATION...
(00Z TAFS)
Issued at 457 PM MST Mon Jan 16 2023
CIGS BKN-OVC040-060 through the night, potentially dropping to
030 on occasion. Very light SHRA early then becoming VCSH, if not
already. A return to showery activity by about 12Z Tuesday
morning, continuing through the day. -RA to RA possible at times
with MVFR CIGS and VIS. Winds 10-15G20-25KT from the southwest on
Tuesday.
&&
.FIRE WEATHER...
Issued at 126 PM MST Mon Jan 16 2023
No significant fire concerns for the period although winds will be
breezy to windy. Our cool moist airmass will remain in place through
Wednesday morning with precipitation chances continuing. Snow levels
will range 7500 to 8000 feet with a few inches possible above that
altitude. Winds will top out 15 to 25 MPH in the afternoon with a
few gusts to 35 MPH. This will help foster very good to excellent
vent rates. Precip chances end for Wednesday but conditions remain
breezy. Quieter weather is expected for Thursday before our next
system begins to affect the area late Friday.
&&
.PRELIMINARY POINT TEMPS/POPS...
El Paso 48 55 36 52 / 60 70 10 0
Sierra Blanca 43 52 32 49 / 20 40 20 0
Las Cruces 42 51 30 50 / 70 70 10 0
Alamogordo 45 50 25 49 / 70 70 10 0
Cloudcroft 27 29 13 25 / 70 80 20 0
Truth or Consequences 38 49 29 49 / 50 50 0 0
Silver City 33 39 30 38 / 70 80 20 10
Deming 42 50 27 49 / 70 70 10 0
Lordsburg 40 47 28 48 / 70 70 10 0
West El Paso Metro 45 53 33 51 / 70 70 10 0
Dell City 43 56 29 51 / 40 50 10 0
Fort Hancock 42 57 34 53 / 20 40 20 0
Loma Linda 41 48 29 45 / 50 70 10 0
Fabens 47 57 30 53 / 40 60 10 0
Santa Teresa 44 52 29 50 / 60 70 10 0
White Sands HQ 44 52 33 51 / 70 70 10 0
Jornada Range 44 49 25 49 / 70 70 10 0
Hatch 46 50 27 50 / 60 70 0 0
Columbus 42 52 31 49 / 70 70 10 0
Orogrande 43 52 29 50 / 70 70 10 0
Mayhill 36 42 21 38 / 60 70 20 0
Mescalero 33 39 16 38 / 70 80 20 0
Timberon 31 37 17 37 / 70 80 20 0
Winston 32 42 23 41 / 50 50 20 0
Hillsboro 42 46 23 46 / 60 60 10 0
Spaceport 41 50 24 49 / 50 60 0 0
Lake Roberts 31 37 15 37 / 80 80 20 20
Hurley 35 45 26 44 / 70 70 10 0
Cliff 35 46 19 46 / 80 80 20 10
Mule Creek 35 39 17 40 / 80 80 20 10
Faywood 37 44 27 43 / 70 70 10 0
Animas 42 50 26 49 / 70 70 10 0
Hachita 43 50 27 48 / 60 70 10 0
Antelope Wells 42 50 27 48 / 70 70 20 0
Cloverdale 38 42 27 43 / 80 70 20 0
&&
.EPZ WATCHES/WARNINGS/ADVISORIES...
TX...None.
NM...Winter Weather Advisory until midnight MST Tuesday night for
NMZ402-415.
&&
$$
SHORT TERM...34-Brown
LONG TERM....26-Grzywacz
AVIATION...35-Delizio
AREA FORECAST DISCUSSION
National Weather Service Hastings NE
934 PM CST Mon Jan 16 2023
...Short Term and Climate Update...
.UPDATE...
Issued at 933 PM CST Mon Jan 16 2023
-- Comments regarding at least patchy fog potential Tues AM
mainly in our southwestern zones:
- Obviously preceding day shifter had their hands FULL with the
impending winter storm (totally understandable!), but one
shorter-term weather element that has gotten a bit closer look
this evening is the possibility for some Tues AM fog
particularly within the southwest 1/4 of our CWA.
- Have introduced at least "patchy fog" to our official forecast
for areas mainly southwest of a Lexington-Franklin-Osborne KS
line, with slightly higher confidence "areas of fog" for our
extreme southwest counties (mainly Furnas/Phillips/Rooks). Main
time frame of concern is 4-10 AM.
- These southwestern areas are in theory most favored for at least
light/patchy fog development (and MAYBE localized dense fog per
models such as HRRR), as these areas will: 1) reside nearest
the southern/western fringes of the lower stratus deck currently
blanketing the majority of our CWA (the edges of stratus decks
are often fog prone)...2) these areas will experience the
overall lightest early-AM breezes (solidly under 5 MPH for the
most part).
- THE BOTTOM LINE/SUMMARY: although overall "small potatoes"
compared to the impending winter storm, at least patchy fog has
been added to our forecast for mainly our southwestern CWA for
Tues AM, as at least localized visibility issues for the AM
commute cannot be ruled. Considered introducing a formal fog
mention to our Hazardous Weather Outlook (HWOGID), but with
latest HRRR suggesting the PRIMARY swath of potential dense fog
could set up just west-southwest of our CWA altogether, will
defer to incoming night shifter to monitor the situation.
&&
.DISCUSSION...(This evening through Monday)
Issued at 445 PM CST Mon Jan 16 2023
Key Messages:
* Significant winter storm with heavy snow and wintry mix on track
to impact the region late Tuesday night into Wednesday night.
Impacts to travel are likely on Wednesday, with lingering
impacts through at least Thursday morning in area of heavy snow.
* Portions of the Winter Storm Watch have been upgraded to a
Winter Storm Warning where confidence is currently highest in
heavy snow.
* Potentially sharp transition zone from heavy snow to wintry mix
will likely set up over our forecast area, potentially right
across the Tri-Cities. However, travel impacts are still a strong
possibility due to cold surface temperatures in the 20s.
* The remainder of the forecast looks to be cool, but quiet.
Forecast Details:
Busy shift today with most time spent on upcoming winter storm. In
short, "calm before the storm" tonight and tomorrow with incr clds
and seasonably mild temps - lows in the 20s, Tue highs 36F-47F.
Attention quickly turns to the winter storm Tue night as the
primary upper trough ejects from the Four Concerns region and
onto the High Plains by 12Z Wed. System has sped up slightly (~
3hrs or so), but otherwise can`t say there have been any
significant curveballs presented by today`s guidance compared to
last night. If anything, some of the probabilistic guidance has
trended towards tighter clustering, which suggests they`re getting
a better handle on the system, and significant changes going
forward are less likely. Worth noting that a significant portion
of the upper jet streak will be over land by 00Z tonight, and
certainly by 12Z tmrw AM. Thus, have incr confidence that locally
we`re looking at three distinct "zones" of weather and impacts,
which will be discussed in greater detail below.
As for a broader assessment of the upcoming system, a few things
strike me as vitally important to determining actual outcomes.
1) Appears there is going to be an initial wave of mod to hvy
pcpn late Tue night into Wed AM, associated with direct thermal
circulation between low to mid level frontogenesis and upper level
divergence. Strong forcing for ascent amidst rapidly incr
moisture on 35-45kt H85 LLJ should result in rapidly expanding and
intensifying shield of pcpn - perhaps as early as 06Z in the
W/SW, and certainly by 12Z for vast majority of CWA. What`s
critical with this initial wave is ptype, as this wave will go a
long way in determining overall accumulations. Appears 12Z
guidance is actually in pretty good agreement showing a transition
from hvy snow in the W/NW, to a wintry mix in central areas, to
mostly rain in the far SE. Thus, it`s vital to properly assess
each ptype and duration in order to formulate an accurate forecast
of snow/ice accumulations. 2) Several models (but not all)
indicate a real possibility for dry air to wrap into the system
from the S/SW, for at least portions of the area, such that cloud
ice is eliminated from the column for a significant amnt of time
during the day Wed - perhaps 6+ hrs. Model ptypes are notorious
for accumulating this as snow, as opposed to much more likely
freezing drizzle (fzdz). The 12Z EC, for example, generates up to
1" of snow (assuming 10:1 ratio) where forecast soundings suggest
fzdz is more likely given lack of saturation at temps colder than
-10C. So outside of far N zones (where actual lgt to mod snow is
more likely to persist) and far S zones (where temps will probably
be at or above 32F), most areas may actually transition to fzdz
from late Wed AM through late aftn/early eve. This poses a
significant risk to the downside for snowfall accumulation
forecasts for areas S of Hwy 92. 3) Finally...there remains some
uncertainty as to the organization of deformation and wrap-around
pcpn/snow on the NW side of this system Wed eve into the
overnight. While there will likely be SOME snow accums, areas that
transition to fzdz during the day Wed, may only have a transition
back to lgt snw for 3-6 hrs before accum precip ends. Thus,
amounts after 00Z Thu will likely be on the light side at only
dusting to 2" for most, perhaps 2-3" over the far N. So again,
this stresses the importance of that initial wave of pcpn Wed AM
as to overall chcs of meeting, or exceeding, warning criteria snow
of 6", or more.
As mentioned above, feel there are three distinct zones of impacts
with this system: a northern zone from roughly Elwood to St. Paul,
to Fullerton, a central zone that encompasses the rest of south
central Neb and the N tier of counties in KS, and a third zone
over the far south from Rooks to Mitchell Counties.
Northern Zone: This is where 12Z deterministic and ensemble
guidance was in best agreement for overlapping output of 6"+ of
snow. In fact, aforementioned forcing and low level temps argue
for SLRs at least a little above climo (or above 10:1), so with
storm total QPF averaging 0.75" to 1" in this area, confidence is
now HIGH that these locations will receive heavy snowfall.
Official storm total snowfall is now 10-11" for ODX, and this may
even be a bit low if 15:1 SLRs can truly be realized as Kuchera
method and forecast sounding suggest. Regardless, folks in these
areas should be prepared for extremely poor travel conditions all
day Wed, and it will likely take quite some time even on Thu to
dig out. N-NE winds gusting around 30 MPH, will cause SOME
blowing/drifting, but nothing significant or "near-blizzard"
worthy. Not going to be an overly dry snow, either. 12Z EC
suggests about a 6hr period from Wed AM into early aftn for 1"+
hrly snow rates, and this seems quite plausible given strong lift
through deep layer of profile, significant isothermal layer of -3
to -5C (for dendrite aggregation), and chance of CSI and maybe
even outright CI (thundersnow). This would certainly bring
visibilities down to 1/4 to 1/2 mi and make for very difficult
driving conditions. Have upgraded portion of this "zone" to a
Winter Storm Warning already, and seems probable that absent of
major change with 00Z data that this will be expanded another row
of counties to the S.
Central Zone: By far where the greatest uncertainty exists due to
potential for initial round of pcpn to be a wintry mix, along with
the fact that dry slot could lead to transition to fzdz for
remainder of Wed daytime hrs. With that said, arrival timing and
fact that initial sfc temps will be fairly cold (mid 20s to near
30F) still suggests travel impacts could be significant for Wed AM
commute. Brief sleet, tenth or two of ice accretion, and up to a
few inches of snow will all be possible in this zone, just in the
period between midnight Tue night and noon on Wed. So don`t let
the lower snow amnts fool one into thinking this will be less
IMPACTFUL for travel on Wed. Again, though, use model derived
snow accums in this area with great caution. A transition from
snow/wintry mix to fzdz later in the day on Wed could certainly
keep the slick conditions going thru the Wed PM commute as well.
Wrap around lgt snow could add another 0.5-2" Wed night. Accum
pcpn will likely wrap up by dawn Thu AM, but impacts from prev
snow/ice will probably linger thru Thu AM commute. Summary: High
confidence in at least minor to moderate travel impacts, esp. for
Wed AM commute, but low confidence in exact snow/ice amnts.
Southern zone: Finally, far S counties will likely largely miss
out on this one. Could have some brief wintry mix with onset of
pcpn late Tue night-early Wed AM, but temps 32-35F should minimize
impacts. Highs in these areas should climb to 34-37F, so even if
there`s transition to drzl (which seems probable given dry slot
placement on models), won`t be fzdz with associated impacts. Could
have some impacts crop up Wed eve as temps fall below freezing,
either from lgt fzdz or lgt snw, but probably nothing too
significant. Summary: Medium to high confidence this area will
have least amnt of pcpn, and any travel impacts will probably be
limited to Wed eve.
Fortunately, the rest of the forecast looks to be fairly quiet
through the weekend. Snow amounts will play a large role in temps
going forward...so it`ll probably be on the cool side, esp. for
central and northern areas for late week and into the weekend.
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Wednesday)
Issued at 630 PM CST Mon Jan 16 2023
-- General overview (including winds):
High confidence in precipitation-free conditions and fairly high
confidence in VFR visibility throughout the period (especially at
KGRI). As for ceilings, they are clearly the number one
challenge, as although MVFR is expected to prevail the majority of
the period, some models/guidance hint at at least a temporary
return to VFR and perhaps even a brief period of IFR. Winds not
much of an issue, with sustained speeds at-or-below 10KT
throughout, with direction gradually transitioning from
northwesterly, to northerly, to eventually northeasterly by mid-
late afternoon Tuesday.
- Ceiling details:
We start out under a fairly expansive blanket of MVFR, with the
million dollar question being just how persistent MVFR will remain
going forward? Although some models/guidance hint that a least a
temporary return to VFR (albeit with scattered lower clouds) could
return at some point tonight and perhaps again later in the period
Tuesday afternoon, other model sets (especially RH time height
progs) more strongly suggest that sub-VFR ceiling will be tough to
shake. In the end, opted to lean on the pessimistic side of things
and officially maintain MVFR throughout. Cannot even rule out a
few hours of IFR (especially around sunrise), but was not
confident enough to include any prevailing groups below MVFR.
- Visibility details:
Although am relatively confident that KGRI/KEAR will not
experience any long-lasting and/or dense fog development, there
are at least some indications that especially KEAR could reside
within 50 or so miles east-northeast of an area of more
problematic fog that could develop late tonight/Tues AM,
especially between 10-15Z. Based on current trends, have
reasonably-high confidence that KGRI will remain VFR, but have
introduced a low-end VFR (6SM BR) at KEAR to at least "hint" at
slightly greater light fog potential there.
&&
.CLIMATE...
Issued at 933 PM CST Mon Jan 16 2023
-- BOTH total precipitation AND snowfall daily records for Jan.
18th could be broken on Wednesday at Grand Island/Hastings (our
two primary long-term climate sites for which we issue formal
Record Reports). Details follow:
Grand Island:
- current Jan. 18 precip record: 0.41" in 1931
- current Jan.18 snowfall record: 4.1" in 1931
Hastings:
- current Jan. 18 precip record: 0.50" in 1912
- current Jan.18 snowfall record: 2.5" in 1960
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...Winter Storm Watch from late Tuesday night through Wednesday
evening for NEZ041-047-048-061>063-072>076-082>086.
Winter Storm Warning from midnight Tuesday night to midnight CST
Wednesday night for NEZ039-040-046-060.
Winter Storm Watch from Wednesday morning through Wednesday
evening for NEZ049-064-077.
KS...Winter Storm Watch from late Tuesday night through Wednesday
evening for KSZ005-006-017.
&&
$$
UPDATE...Pfannkuch
DISCUSSION...Thies
AVIATION...Pfannkuch
CLIMATE...Pfannkuch
Area Forecast Discussion
National Weather Service Goodland KS
422 PM MST Mon Jan 16 2023
.SHORT TERM...(This evening through Tuesday Afternoon)
Issued at 233 PM MST Mon Jan 16 2023
At the beginning of the short term period, the latest RAP analysis
shows the CWA having a westerly flow aloft being underneath the base
of a large, broad upper air trough. Current observations and
satellite imagery show dry conditions with some scattered high
clouds moving eastward across the northwestern quadrant of the CWA
and a few high clouds moving eastward out of Gove and Graham
counties. Forecast models show this flow continuing through the
remainder of the day with an upper air low over northern CA starting
to form another trough in the west overnight tonight. Forecast
guidance shows this trough deepening and moving eastward with the
low being over UT by the late afternoon hours on Tuesday. The CWA
upper air flow looks to continue to be westerly during the day
before beginning to turn southwesterly as the front part of the
trough reaches over the CWA by late Tuesday afternoon.
At the surface, the Tri-State area looks to stay dry throughout the
short term period. Surface winds look to be out of the northwest
around 10-20 kts during this afternoon/evening before becoming
slowing and becoming variable overnight and then becoming easterly
to southeasterly at 10-15 kts during Tuesday afternoon. The main
concern in the short term looks to deal with possible fog on
Tuesday morning. While most models agree with the potential for
fog for a good portion of CWA for a few hours with low dew point
depressions and light winds, they don`t quite agree with how low
the visibility will get. Not enough confidence for a Dense Fog
Advisory yet, but put in patchy fog in portions of the CWA from
around 8Z-16Z. Will continue to monitor this in case visibilities
drop and adjust as necessary.
Daytime highs for today look to be in the 40s and 50s while
overnight lows for tonight look to range between the upper teens and
middle 20s. Tuesday`s daytime highs should range between the
middle 30s and the middle 40s.
.LONG TERM...(Tuesday night through Monday)
Issued at 335 PM MST Mon Jan 16 2023
A rather impactful winter storm system will move through the Tri-
State area Tuesday night through Wednesday night.
A trough that has recently made landfall on the west coast will move
over the Four Corners region and on eastwards as it begins impacting
the Great Plains Tuesday night. A surface lee low will form as an
extension of this trough. The potential paths of the lee low are
narrowing, but still are subject to change. The lee low will begin
influencing the Tri-State area Tuesday night and we expect
precipitation to begin around 0Z Wednesday. The system is expected
to travel to the east-northeast across the southern portion of the
CWA and produce heavy snowfall to the northwest of it`s cyclone
center.
Although the exact areas of highest snowfalls could change, areas
along and north of I-70 could see more than 6 inches of snow with
locations along and north of highway 36 seeing up to 11 inches of
snowfall. Winds will become northerly during the event and could
gust up to 27 kts near the Tri-State border with 35 kts gusts
possible south of I-70. This could lead to blowing and drifting snow
that can reduce visibility.
There is also a chance of freezing rain/drizzle occurring in the
southeastern quarter of the CWA. Confidence is low that accumulating
ice will occur, primarily due to the warm nose around 750 mb being
very small and close to freezing. If freezing rain does fall, it
will likely start around 03Z Wednesday and end before 18Z. The
freezing rain would occur as the precipitation transitions from rain
to snow. Snow is expected to be the dominate P-type throughout the
event due to a strong dendritic growth zone and temperatures that
will likely continually cool after midnight, giving us a midnight
high temperature. As temperatures cool throughout the event, the
snow-liquid ratios will increase. The ratios will start out around 8-
10:1 and increase to 13-14:1 by the end of the event.
The snow will exit the CWA to the northeast before 6Z Thursday due
to a weak ridge moving into the area. Impacts throughout the event
will include hazardous travel conditions, possible road closures,
reduced visibility, and moderate to heavy snowfall on top of pre-
existing snowfall.
On the morning of Thursday, models depict the upper air low being
over IA with a weak ridge west of the CWA and another trough west of
that over the western CONUS. This setup giving the CWA a
northwesterly flow during the day that turns westerly by Thursday
evening as the ridge moves over the CWA. Going into Friday, forecast
guidance shows the far western trough moved further eastward with a
low having developed in the base over the UT/AZ border in the
morning. A trailing strong ridge helps turn this trough in a more
positive orientation during the day allowing for southwesterly flow
throughout the majority of the day. By Saturday morning, models show
the axis of the trough passing over the CWA with the GFS having an
open wave while the ECMWF still shows an upper air low possibly
starting to close off over NM. The front part of the trailing ridge
makes it over the CWA by the Friday afternoon hours allowing for a
north-northeasterly flow during the remainder of Saturday. From
Sunday onward, the GFS and ECMWF depart from their model solutions
as the GFS has the ridge passing over the CWA on Sunday afternoon as
another upper air low moves over the MT/ID/WY border. By Monday
morning, the GFS shows the CWA having a southwesterly flow aloft as
the front part of a positively tilted upper air trough moves over
the CWA and remains there for the rest of the day. Alternatively,
the ECMWF shows an upper air low developing over Saskatchewan on
Sunday morning that moves downward into ND by the evening as it
starts to close off giving the CWA a southwesterly flow aloft. For
Monday, the low moves over SD by the afternoon and then into central
KS by the night hours resulting in a northerly flow aloft. Due to
the uncertainty seen in the latter days of the long term period,
future model runs will be monitored for better agreement.
At the surface, the CWA looks to see two additional chances for
wintry precipitation are seen on Friday and on Sunday evening into
Monday morning. For the system on Friday, forecast QPF looks to be
minimal at this time with not much snowfall as a result. With
Sunday/Monday`s upper air pattern being quite uncertain, so does the
chances for precipitation on both days. Will monitor as these models
become more certain and the systems become less theoretical in the
future. Fire weather does not look to be a concern at all with
minimum RH values being well above criteria.
The Tri-State Area expects to see daytime highs in the upper 20s to
lower 40s on Friday followed by Saturday having high temperatures in
the lower to upper 30s range. Sunday`s daytime highs look to be in
the lower 30s to middle 40s range while Monday sees coolest daytime
highs in the middle 20s to lower 30s range. Overnight lows on Friday
look to be in the upper single digits to upper teens range followed
Saturday and Sunday overnight lows in the lower to upper teens.
Monday night sees low temperatures in the lower single digits to the
lower teens. Wind chills look to be in the negative and positive
single digits and stay above advisory criteria at this time though
it will be monitored should these change.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 422 PM MST Mon Jan 16 2023
For KGLD, VFR conditions through 13z Tuesday, then IFR conditions
with 1sm or less in fog and ceilings down to BKN015 at times. By
17z, MVFR skies. Winds, northwest 5-10kts becoming light/variable
by 13z Tuesday. By 15z, southeast around 10kts.
For KMCK, VFR conditions through 06z Tuesday, then MVFR w/
ceilings around BKN020. By 12z, LIFR/IFR conditions with
visibility 1sm or less in fog and ceilings below OVC010. VFR from
18z onward. Winds, northwest 5-10kts through 15z Tuesday, then
light/variable.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...Winter Storm Watch from Tuesday afternoon through Wednesday
evening for KSZ001>004-013>016.
CO...Winter Storm Warning from 5 PM Tuesday to 5 PM MST Wednesday for
COZ090.
Winter Storm Watch from Tuesday afternoon through Wednesday
evening for COZ091.
NE...Winter Storm Warning from 5 PM MST /6 PM CST/ Tuesday to 5 PM
MST /6 PM CST/ Wednesday for NEZ079>081.
&&
$$
SHORT TERM...076
LONG TERM...CA/076
AVIATION...JN
Area Forecast Discussion
National Weather Service Grand Rapids MI
1034 PM EST Mon Jan 16 2023
LATEST UPDATE...
Update
.UPDATE...
Issued at 1033 PM EST Mon Jan 16 2023
Surface low pressure is centered in Southwest Wisconsin at 03Z.
Southwest Lower Michigan is a southeast to south mild/moist flow
of air off to the east of the low which is resulting in
widespread low clouds and fog. The system is nearly vertically
stacked when looking at water vapor imagery. The system is only
forecast to slowly move to the northeast tonight across Wisconsin
resulting in very little change in our conditions here in
Michigan. Low clouds and fog will continue as well as occasional
drizzle tonight. The drizzle setup is clearly seen in BUFKIT
overviews with deep low level moisture coincident with vertical
motion and an unsaturated DGZ. Based on regional radar trends and
the latest runs of the HRRR we will see isolated to scattered
rain showers as well.
&&
.DISCUSSION...(This evening through next Monday)
Issued at 302 PM EST Mon Jan 16 2023
...Rain...
Radar shows rain spreading northeast across the cwa, which is really
good news considering much of the cwa east of US-131 is in some form
of drought. For the most part, observation stations over the north
central cwa show temperatures abv freezing lessening the concern for
freezing rain. Low pressure over Iowa will be slow to move northeast
and really won`t clear the cwa until Tuesday afternoon. Thus we`ll
see light rain continue through the evening before becoming showery
overnight as the effects of the sfc low diminish in favor of the
trailing upper low. Additional rainfall of 0.1-0.2 inches expected
through tomorrow afternoon.
A little colder air will work in on the back side as the low moves
away Tuesday night and there could be some mixed rain and snow
showers over Osceola/Clare counties after 06z Wednesday.
...Next Precip Maker Wednesday Night/Thursday...
ECMWF/GFS have been consistent in tracking a Southern Plains low
northeastward from Oklahoma to Michigan Wednesday night. The ECMWF
takes the low across central Lower which places any snow that falls
over the northern cwa. The GFS has been consistent in taking a
slightly more southerly track which brings a bit colder air farther
south into the cwa. Ensembles bear that out with the ECMWF mean at
Grand Rapids less than an inch and GFS ensembles averaging around 3
inches. A sizable portion of the GFS ensemble member low tracks
take the system north of I-96, giving some credence to the ECMWF and
that`s the way we`ll lean. Thus, we`re looking at generally rain
south of M-57 and snow or mixed rain/snow north of there. Total
snowfall accumulation north of M-57 from Wednesday night through
Thursday will be in the 1-3 inch range. Forecast soundings suggest
some freezing rain may also mix in along the US-10 corridor east of
US-131 as well.
...Dry Weekend...
Once the Thursday system moves east, Friday and Saturday look dry. A
southern stream system moves toward the Ohio Valley. The dryer ECMWF
would keep us dry through the weekend, but the GFS phases the
trailing short wave with a deeper low behind it and draws moisture
northward. That would produce some light snow over the southern cwa
if it happens.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 718 PM EST Mon Jan 16 2023
Poor aviation conditions are expected to remain in place the next
24 hours. Ceilings will be IFR and LIFR the entire time with bases
below 1,000 feet. The best chance at LIFR will occur overnight
between 06Z and 12Z. As for visibilities, MVFR is the most likely
category (3-5SM) as winds in the lowest 2K feet will 20-40 knots.
Winds of that speed will preclude visibilities from dropping too
much. Winds will gradually veer from the southeast this evening to
southwest and west on Tuesday as low pressure passes by to our
northwest.
&&
.MARINE...
Issued at 302 PM EST Mon Jan 16 2023
We`ve extended the Small Craft Advisory through Wednesday morning.
Despite there likely being a lull in wind tonight, winds will pick
up Tuesday ahead of the next low and continue into Wednesday,
resulting in hazardous conditions to small craft.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...Small Craft Advisory until 11 AM EST Wednesday for LMZ844>849.
&&
$$
UPDATE...Duke
DISCUSSION...04
AVIATION...Duke
MARINE...04
Area Forecast Discussion
National Weather Service North Platte NE
558 PM CST Mon Jan 16 2023
...00Z AVIATION UPDATE...
.SYNOPSIS...
Issued at 403 PM CST Mon Jan 16 2023
Key messages:
- Patchy fog to areas of fog tonight into Tuesday morning across
the west.
- A winter storm is forecast to bring heavy snow to a large
portion of western and north central Nebraska from late Tuesday
night into Wednesday evening. Winter Storm Warnings and Winter
Storm Watches are in effect.
&&
.SHORT TERM...(This evening through Tuesday night)
Issued at 403 PM CST Mon Jan 16 2023
The latest hi-resolution models including the HRRR and RAP are
forecasting fog for areas near and west of Highway 83 tonight into
Tuesday morning. Some of the fog could be locally dense. A
saturated shallow layer will have drier air aloft and clear to
partly cloudy skies to promote fog formation.
A deep upper trough will move into the Intermountain West tonight.
GFS 500mb height anomalies are near 225 meters below normal
across srn California into western Arizona by 12Z as upper ridging
begins to develop upstream across the Central Plains.
On Tuesday, The upper trough with a closed low will reach the
Four Corners by late afternoon. An easterly upslope flow will
develop across Kansas and Nebraska into eastern Colorado and
southeast Wyoming. Skies will become cloudy all areas with stratus
expected. this will hold highs down during the day to the low to
mid 30s.
A winter storm is forecast to move into the area Tuesday night as
the closed upper low moves into southeast Colorado by 12Z
Wednesday. A well-defined deformation zone is expected to develop
north of the closed low from northeast Colorado into the southern
panhandle, southwest Nebraska and far northwest Kansas. After
midnight, six hourly QPFs forecast to range from 3 to 4 tenths of
an inch near and south of highway 2. Heavy snow is likely to
occur with snowfall amounts from 2 to 4 inches and upward of 5
inches.
.LONG TERM...(Wednesday through Monday)
Issued at 403 PM CST Mon Jan 16 2023
Model consensus from the is for the H5 low to track from far
southeast Colorado 12Z Wednesday, across north central Kansas by
00Z Thursday, then into central Iowa by 12Z Thursday. This is a
favorable storm track for our forecast area to receive heavier
QPFs. Ensemble mean QPFs from the ECMWF, Canadian and GFS places
the axis of heaviest precipitation across northeast Colorado,
through southwest and central into eastern Nebraska. The latest
NBM has increased POPS to near 90 percent across southwest into
central Nebraska. Confidence is now medium to high on the track of
this system based on ensemble mean QPFs. Trends in placement of
ensemble means are fairly consistent, with the ECMWF to most
consistent the past few runs. Based on the latest WSSI index and
the track of this system, A Winter Storm Warning has been issued
for all counties near and south of Highways 2 and 91. Storm total
snowfall amounts from 7 to 11 inches and locally higher are
forecast. Meanwhile a Winter Storm Watch was issued for all
remaining counties in north central Nebraska. Storm total snowfall
amounts in the watch area of 3 to 9 inches are possible. The
potential for a wet heavy snow exists. Snowfall rates of an inch
per hour are supported, and could near two inches per hour for a
few hours. Moderate to heavy snow is expected. Northeast winds on
Wednesday will become northerly with gust to 25 mph possible. This
could create some blowing and drifting. This winter storm is
shaping up to be a major winter storm. In fact, at North Platte
Airport, the daily record snowfall is 9 inches set in 1988. The
latest forecast is near 10 inches. Also the daily record water
equivalent is 0.76 inches. set in 1883. The forecast amount is
0.90 inch.
Another upper trough is forecast to drop southeast from the
Rockies into the Central and Northern Plains Thursday night into
Friday night. Low level moisture look quite limited. Current NBM
forecast is just a 20 percent chance of light snow across far
southwest Nebraska.
Regarding high temperatures this week, mid to upper 20s Wednesday,
upper 20s to lower 30s Thursday and Friday, and low to mid 30s
Saturday and Sunday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 549 PM CST Mon Jan 16 2023
Low stratus will continue to filter in from the northwest this
evening leading to deteriorating flight conditions at area
terminals. Expect a quick onset to MVFR at LBF with overnight CIGs
falling to IFR conditions. IFR with periodic LIFR criteria
conditions are likely to persist at VTN through the period. Though
CIGs improve gradually late in the period at LBF, onset of
precipitation and a return to IFR will occur just beyond the valid
period.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
Winter Storm Watch from Tuesday evening through Wednesday
evening for NEZ004>010-094.
Winter Storm Warning from 6 PM CST /5 PM MST/ Tuesday to
midnight CST /11 PM MST/ Wednesday night for NEZ022>025-035>037-
056>059-069>071.
Winter Storm Warning from midnight Tuesday night to midnight CST
Wednesday night for NEZ026>029-038.
&&
$$
SYNOPSIS...Roberg
SHORT TERM...Roberg
LONG TERM...Roberg
AVIATION...NMJ
Area Forecast Discussion
National Weather Service Pendleton OR
610 PM PST Mon Jan 16 2023
.UPDATE...A dense fog advisory was issued for the Kittitas
valley. Area web cams along I-90 Thorp-Kittitas show reductions in
visibility along with KELN reporting dense fog for the last two
hours. High clouds are currently masking low clouds on satellite
but a persistent deck and fog was present across the Kittitas
valley prior to the loss of sunlight. Looking at obs in/around
the valley, a slight inversion to isothermal conditions inferred
at surface and near surface with the surface saturated. "Virtual
soundings" dew point profile show little-to-no change in the
vertical that is composed of nearby obs. This is in tandem with
surface high pressure near/overhead where there is more
subsidence. As such, current thinking is this setup will maintain
the fog present over the Kittitas valley. Looking at guidance, a
limited signal is present in the latest HREF but there are modest
probs of 1/2 mile or less (appears up to 50%). Likewise, guidance
isn`t capturing the current situation. Dense fog advisory goes
through 10 AM. Meantime, with temperatures cooling just slightly
may see some slippery conditions with dense freezing fog as well.
Elsewhere, confidence in hazardous conditions from fog across the
Lower Basin, Blues, and the eastern Gorge is low (less than 30-50%
confidence but will monitor). Albeit, slightly higher confidence
in the Northern Blues/Meacham. Current moisture setup and surface
dewpoint depression lowers confidence across the Gorge and Lower
Basin at this time.
&&
.PREV DISCUSSION... /issued 218 PM PST Mon Jan 16 2023/
SHORT TERM...Tonight through Wednesday night...A broad upper
level trough is present over the western U.S. with a split flow
aloft. The strongest energy is over the Great Basin in the
southern branch of the flow. Marginal instability associated with
the weak cyclonic flow has resulted in a isolated mountain snow
showers, and there is a weak embedded wave that will bring
scattered snow showers to the WA and northern OR Cascades
overnight. Otherwise, the only noteworthy weather tonight will be
the return of fog and some freezing fog. Dense fog developed early
this morning in the Kittitas Valley, the eastern Columbia River
Gorge, and locally in the Yakima Valley. There will be more
subsidence and stable conditions as a shortwave ridge builds over
the region. The latest NBM seems to be catching up with the
increasing potential for fog and low clouds based on its latest
runs with CIGS less than 1000 feet in the same areas that had
dense fog this morning as well as across Benton and Franklin
Counties. The HREF visibility from the mean ensemble solutions
also shows this area with 4000-6000 meters (2-3 miles) in
visibility tonight. Additional Dense Fog or Freezing Fog
Advisories may be needed tonight.
Tuesday will be another dry day with the exception of 20-40 pct
chance of snow along the WA/OR Cascade crest. This is associated
with a weak west-northwest flow aloft and a shallow front
bringing precipitation west of the Cascades. The shortwave ridge
will travel east Tuesday night, and the upper flow will increase
from the southwest.
A well-defined cold front off the coast will move inland Wednesday
morning, but the front will stretch apart in a split flow aloft.
Run by run, models are trending with less QPF and less wind. The
front will lower snow levels down to around 1500 feet, and there
will be snow accumulations in the mountains and valleys.
Therefore, the winter weather needs to be addressed in terms of
road conditions. However, snow accumulations will be light and are
not expected to meet advisory criteria. The GEFS and ECMWF
ensembles all show MEH receiving 2-4 inches of snow, and SMP
around 3-7 inches. Although snow levels lower considerably behind
the front, there will be drier air with little to no accumulation
in the Lower Columbia Basin and surrounding valleys. Just ahead of
the front, slight warm air advection aloft will bring a slight
chance (15 pct) of light freezing rain or sleet along the east
slopes of the Cascades Wed morning. This was a tough decision on
whether or not to add a chance of freezing rain to the forecast.
The HREF shows precipitation type as snow through 12Z Wednesday,
but the HRRR has an area of mixed precipitation early Wednesday
morning, mainly near the Mt. Adams area. Will have the slight
chance in the forecast for a few areas along the Cascade east
slopes. Wister/85
LONG TERM...Thursday through Tuesday...The main concerns in the
extended forecast period are a departing upper trough on Thursday,
and then another upper trough for Saturday and Sunday. An upper
low pressure system will be sagging southward with the flow aloft
becoming northerly in the wake of a departing upper low on
Thursday. This will likely result in cooler temperatures from what
we have recently been having. Temperatures will be near steady
from Thursday - Friday, and then a couple of degrees warmer on
Saturday ahead of another upper trough passage. Then they will be
cooling again on Sunday through Tuesday behind that next trough.
There are some significant differences between the deterministic
models, mostly with the depth and amplitude of the upper trough by
Saturday. Cluster analysis for Saturday shows the GFS having an
80 percent variance in one of the clusters, with a variance of
45 percent by the Canadian, and only 12 percent by the ECMWF. As
such, have little confidence in the sharper depth and amplitude of
the GFS and Canadian solutions, and am leaning more to the ECMWF
solution. However, with that said, the flow will still become
northerly again by Sunday, with better agreement between the
deterministic models and ensembles by Thursday evening. However,
deterministic models will diverge again on Saturday. Then they
become more in line with each other again by late Tuesday. These
fluctuations on consistency leave the extended period more
uncertain with lower confidence in the forecast.
There will be enough moisture with the upper trough on Saturday
and Sunday for some light snow in the mountains, and mostly rain
in some of the lower elevations, mainly along the Cascades and the
eastern and northeast mountains. However, snow amounts will only
be a dusting to an inch in the lower mountains and mountain
valleys, and up to only 3-5 inches over the crests of the Cascades
and the higher peaks and ridges of the eastern and northeast
mountains. Elsewhere in the forecast area, precipitation will be
either very light, or none at all, with any snow accumulations
less than a half inch, and QPF amounts less than a hundreth or two
of an inch. Therefore, and not anticipating any winter weather
highlight amounts of snow at this time. All of the NBM
probabilities are very low (10 to 20 percent), for even the
highest peaks and ridges for advisory or warning amounts of snow.
The rest of the long term will be mostly dry outside of Saturday
and Sunday.
High temperatures will start out in the lower to mid 40s lower
elevations on Thursday through Saturday, and then cooling to the
mid 30s to lower 40s on Sunday through Tuesday. Low temperatures
will start out in the upper 20s to mid 30s lower elevations, and
teens and 20s in the mountains on Thursday. Then they will cool
to the lower to mid 20s by Saturday, but warming a bit again on
Sunday before cooling again to the upper teens to mid 20s Monday
through Tuesday in the lower elevations. In the mountains low
temperatures will be in the upper single digits to upper teens
Friday and Saturday, cooling to the mid single digits to mid teens
by Monday and Tuesday.
Winds are expected to be light in most areas through most of the
extended period. However, it will be locally breezy on Thursday
with the departing upper trough, and then again on Saturday
afternoon and evening with the next upper trough passage. Then
they will become light again for Sunday night through Tuesday. 88
AVIATION...00Z TAFs...The LIFR to MVFR conditions at KDLS, KYKM,
have become mostly VFR this afternoon, and will remain so through
the evening. After that, night time radiational cooling will
allow the lower elevation inversions to become stronger again,
which will result in all terminals having LIFR to MVFR conditions
again by tomorrow (Tuesday) morning. These conditions will likely
persist through most of the day Tuesday. Winds will be light at
all terminals through the next 24 hours and less than 10 Kts. 88
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 32 44 32 47 / 0 0 0 40
ALW 33 44 32 46 / 0 0 0 30
PSC 32 42 32 47 / 0 0 0 30
YKM 28 41 29 42 / 0 0 10 60
HRI 32 45 32 48 / 0 0 0 30
ELN 29 38 28 39 / 0 0 10 70
RDM 26 42 29 44 / 0 0 0 70
LGD 30 39 27 38 / 10 0 0 30
GCD 28 39 26 41 / 10 0 0 50
DLS 35 45 35 46 / 10 10 20 90
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...Dense Fog Advisory until 10 AM PST Tuesday for WAZ026.
&&
$$
SHORT TERM...85
LONG TERM....88
AVIATION...88
UPDATE...80
Area Forecast Discussion
National Weather Service Pueblo CO
333 PM MST Mon Jan 16 2023
.SHORT TERM...(This evening through Tuesday)
Issued at 147 PM MST Mon Jan 16 2023
Key Messages:
1) Moderate to heavy snow continues tonight into Tuesday over the
higher terrain, with the highest snowfall amounts expected over the
eastern San Juan mountains.
2) Snow moves into the Pikes Peak region and Palmer Divide very late
in the day on Tuesday.
Relatively quiet day today, as the upcoming mid week system takes
shape over the western CONUS. Some development has occurred across
the Continental Divide today, though amounts and impacts have been
limited given the lacking large scale support. With the approaching
system and more energetic flow, will likely see development ramp up
across the Continental Divide this evening, especially across the
southwest mountains. This will support returning moderate to heavy
snowfall to these locations tonight into Tuesday. With snow
development also increasing over remaining areas of the higher
terrain tonight, no changes were to the current Winter Weather
Advisories and Winter Storm Warning in place. As snow increases
across the mountains this evening, some scattered snow shower
development across the high mountain valleys will be possible
tonight. This potential looks to increase more so Tuesday,
especially across the San Luis Valley, with the approach of the
upper level system. Amounts do look to be on the light side for the
San Luis Valley, though isolated stronger snow showers can`t be
ruled out.
As the upper level system rapidly approaches later in the day
Tuesday, will really see development increase in coverage and
intensity across most of the higher terrain and mountain valleys.
This development will begin to spill into the Pikes Peak region and
Palmer Divide very late in the day. Given the warmer initial
conditions in place, think impacts will be limited during this time.
That being said, guidance is showing a quick ramp up in large scale
ascent. So, even if the snow may not accumulate on area roadways
late Tuesday afternoon, there could be some stronger snow showers
with potential significantly reduced visibility. Elsewhere across
the southeast plains, rain showers and even some rumbles of thunder
will be possible late in the day Tuesday.
.LONG TERM...(Tuesday night through Monday)
Issued at 147 PM MST Mon Jan 16 2023
Key messages:
1) Snow will be likely for the higher terrain, and possible over
portions the plains from Tuesday evening through early Thursday
morning.
2) Strong winds with blowing snow will be possible throughout the
afternoon and evening on Wednesday over the eastern plains and
Palmer Divide with reduced visibilities at times.
3) A colder storm will impact the region later this week and through
the early part of the weekend with more chances of snow, especially
for the plains on Friday through Saturday morning.
4) A third system will impact portions of southeast Colorado
beginning late Sunday into next Monday.
4) Temperatures throughout the week will continue to get
progressively colder and well below the seasonal average for most
locations by Friday, with only a slight rebound through the weekend
and then cooler again next Monday.
Detailed discussion:
Tuesday night through Tuesday...
The longwave trough over the western CONUS will continue to deepen
and advance towards the region, along with a major shortwave trough
associated it, which will allow for the southwesterly flow to
provide snow over the higher elevations. There will be considerably
higher amounts likely over the Eastern San Juan Mountains, with some
areas receiving as much as 2 feet of additional snowfall during this
period in the forecast. Along with this will be stronger winds
across the peaks and this will likely result in tricky travel
conditions for the Wolf Creek pass with blowing snow and occasional
white out conditions. Lesser amounts will occur over the Central and
Sangre de Cristo Mountains, given the orientation of the winds and
moisture feed in the mid levels. Although, there will still be new
snowfall accumulations between 3 to 5 inches, and with the stronger
winds, will make for tricky travel for places such as Monarch Pass.
Ahead of this system, there will be some areas of areas of unstable
CAPE with values of up to 300 J/kg moving over the plains during the
later hours of the evening tomorrow, which could produce some a few
isolated convective showers and possibly an isolated thunderstorm.
There also will be some weak instability over the San Juan Mountains
which could result in thundersnow. Initially, all of the
precipitation will begin as rain for most of the plains, then
transition to snow during the early morning hours on Wednesday as
colder air is advected in from the north and snow levels drop.
Model guidance at this time is still having a difficult time with
the placement of the associated surface low pressure center with
this major shortwave trough, and has been fluctuating between it
being further to the north over the lower Arkansas River Valley and
southward closer to the CO/NM border. The latest GFS runs have been
trending to the location being further to the south, which could
help to increase snowfall totals over the plains if it verifies. The
HRRR has been keeping things much drier that other models, but it
could be over-mixing with a dry bias that has this model
under-performing with QPF. Due to this, there is not high confidence
at this time where exactly the position will be, and the difference
of the low being slightly altered to the north or south could make a
drastic change on how much snow the plains receive on the backside
of the low. A slight change in the upcoming models could produce a
much different outcome in terms of snowfall totals across the
plains, and therefore this will continue to be closely monitored as
this storm evolves.
The general track with a consensus of the models continues to be
more to the northeast, yet the GFS model does appear to be taken the
track more to the ENE. A more NE`ly track would not favor much of
the southern I-25 corridor getting as much wrap around moisture, but
a more ENE`ly track may help to bring in a little more moisture over
this area and there could be better snowfall amounts if this does
occur. The northern I-25 corridor, especially the Palmer Divide,
still looks to do very well with snowfall amounts with a majority of
the higher resolution models. In addition, there will be a period
during the early morning hours where the southern I-25 corridor
could do better with snowfall, depending on how far south the TROWAL
(trough of warm air aloft) extends. Given the position of the low,
there could also be higher amounts over the eastern plains, along
the CO/KS border, mainly north of highway 50. Again, this will all
depend on where the low pressure center establishes itself. With
colder air advected in from the north, temperatures will be around
10 degrees colder for highs on Wednesday from where they are
expected to be on Tuesday.
Along with snowfall will be stronger winds on the backside of the
low as well as it undergoes cyclogenesis and tightens the pressure
gradient at the surface. There could be some locations over the
eastern plains with gust exceeding 30 mph by the afternoon on
Wednesday. These winds, in combination with heavier snow bands
(depending on where they set up) could cause significantly reduced
visibilities for areas of the lower Arkansas River Valley and
northward due to blowing snow. There could also be areas of El Paso
County, mainly the Palmer Divide and Monument Hill that also will
experience blowing snow through the early mornings on Thursday. Some
areas that receive several inches of snowfall, with the most likely
locations being over the Palmer Divide and eastern Kiowa County.
Most models have been consistent with a majority of the snow ending
by around noon on Thursday, this clearing taking place throughout
the afternoon as the low progresses further east and allows for high
pressure to begin building back in. Highs will be slightly
warmer and winds will also diminish into the evening hours.
Friday through Saturday...
Determinist and ensemble models alike are in somewhat agreement with
the progression of another shortwave trough that will be propagating
over the region on Friday. Although, the position of the low
pressure center has continued to be inconsistent. The GFS now has a
secondary low over northeastern Colorado late Friday evening and the
main low is much closer to our CWA, over northern New Mexico. The
ECMWF is much further to the southwest, over southeastern Arizona,
and the Canadian has the low almost directly over the center of
Arizona. The leads to more uncertainty as to how much this storm
will impact southeastern Colorado in terms of snowfall. If the GFS
verifies, there will be better snowfall amounts for the plains with
a more favorable setup for isentropic upgliding. A cold front will
move through during the morning, and it will be a colder airmass as
well and NBM has continued to trend down slightly with the high
temperatures for Friday in recent model runs. Snow will continue
over the mountains and southern plains into the early morning hours
and then taper off later in the day on Saturday. It will also begin
to warm up slightly on Saturday as high pressure builds back in over
the region.
Sunday through Monday...
With the ensembles, the slightly warming trend looks to continue
throughout the weekend as a weak ridge temporarily builds in ahead
of the next shortwave. This shortwave will have a very similar
propagation to the one that moves over on Friday. Snow will begin
over the mountains late Sunday evening, and this wave could also
provide another shot at snow for the plains. It will also send
another cold front through with a cooldown in temperatures again for
highs on Monday. -Stewey
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 147 PM MST Mon Jan 16 2023
VFR conditions and dry weather are expected across PUB and COS
through much of this period, with mid/high clouds continuing to
periodically move overhead. With some potential for isolated
rain/snow showers at both locations, did add a VCSH late Tuesday
afternoon. Generally lighter winds in place, with steadier east
southeast winds returning during the day Tuesday. Expect similar dry
weather with VFR conditions at ALS for much of tonight. As snow
increases over the mountains this evening, there is some potential
for some isolated snow showers to move across the terminals during
that time. While this is a possibility, think drier weather will
prevail and so have continued a dry TAF tonight. Guidance continues
to suggest a trend towards MVFR ceilings at ALS early Tuesday
morning, so did lower ceilings during this period. Snow development
does look to increase Tuesday morning, and don`t see why lowering
ceilings won`t be a likely scenario. Then, expect periodic snow
showers for ALS for much of Tuesday with southerly winds/gusts
increasing in the afternoon.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from 2 PM Tuesday to 5 PM MST Wednesday
for COZ058-059-081-082.
Winter Weather Advisory from 5 PM this afternoon to 5 PM MST
Wednesday for COZ060.
Winter Weather Advisory from 5 PM this afternoon to 2 AM MST
Wednesday for COZ065>067-073-075.
Winter Storm Warning from 5 PM this afternoon to 2 AM MST
Wednesday for COZ068.
Winter Storm Warning from 5 PM Tuesday to 5 PM MST Wednesday for
COZ084.
&&
$$
SHORT TERM...RODRIGUEZ
LONG TERM...STEWARD
AVIATION...RODRIGUEZ
Area Forecast Discussion
National Weather Service Riverton WY
643 PM MST Mon Jan 16 2023
.UPDATE...
Issued at 640 PM MST Mon Jan 16 2023
Dense freezing fog continues and has expanded across the Wind
River Basin this evening. A Dense Fog Advisory has been issued
through 5 AM Tuesday due to area observations and webcams
reporting very low visibilities across much of the Basin. Light
winds should prevent much movement of the fog through the
overnight hours. Fog will become light snow around sunrise or
during the early morning hours Tuesday.
&&
.SHORT TERM...(This evening through Tuesday night)
Issued at 1230 PM MST Mon Jan 16 2023
The deformation area and weak shortwave trough that produced the
snow from yesterday into last night has moved northeast to the
northern Plains today. Some lingering light snow showers are
possible for a couple of hours yet over the Bighorn Mountains and
northern Johnson County, but should finish up this evening. Patchy
dense fog is the story for today as several basins have been
dealing with it for hours, including the Upper Green River Basin,
the Wind River Basin, and the Bighorn Basin along the Bighorn
River. Sunlight and warming should help to dissipate the fog
during the late morning and afternoon hours, but it`s also
entirely possible for the fog to hold on through the afternoon,
especially from Big Piney to Pinedale and along the Wind River
where very light wind and poor insolation will keep the cold pools
intact. Have adjusted the forecast to include the possibility of
patchy fog remaining through the day, then strengthening again
this evening and overnight. Winds will be on the light side today
with some areas seeing gusts 20-25 mph this afternoon.
An upper-level low over central California will move eastward late today
into Tuesday, increasing moisture and clouds from the southwest.
High clouds are already pushing into southwest WY. Latest model
runs indicate snow showers developing across SW WY and Sweetwater
County between 3-6 AM Tuesday morning and moving northward through
the day. As the low moves over central UT, a decent surface low
also develops over the same area, reversing the pressure gradient
such that N-NE winds develop over central and southern WY Tuesday
afternoon, leading to upslope conditions from some areas Tuesday
afternoon and evening. According to the latest NAM and HRRR runs,
a first shot of precipitation will develop across Sweetwater and
Sublette Counties, then move NE into central WY and the southern
Bighorn Basin during the day. As the low moves into central CO
Tuesday evening into Wednesday morning, the surface flow becomes
more northerly, and snow will increase from southern Johnson into
Natrona County and westward into eastern Fremont County. Winds
could gust as high as 30 mph and cause blowing and drifting snow
issues along some travel corridors. The current forecast is
calling for 1-3 inches across portions over SW into southern and
central WY, with some locally higher 3-5 inch amounts. Areas in
the northern Bighorn Basin as well as YNP have the lowest expected
amounts under half an inch. While mid-level temperatures drop a
few degrees to increase the instability with the storm, surface
temperatures will be persistent until later Wednesday into
Thursday when skies clear some and the storm moves to the east.
.LONG TERM...(Wednesday through Monday)
Issued at 100 PM MST Mon Jan 16 2023
The mid-week upper-level low will be moving eastward from Colorado
into Kansas Wednesday morning. Our forecast area will see
lingering snow showers with mean northerly flow, mainly over
central into southern WY. The snow showers should diminish by
noon, with skies clearing from the northwest. Behind the trough
axis, colder mid-level air will move over WY with northwest flow,
making for a chilly day and night. Thursday morning is likely to
see temps drop to singles digits above and below zero for most of
the area. Another upper-level low from the PacNW will slide SE
into the Great Basin on Thursday, increasing clouds early across
western WY with some light snow showers possible in the northwest
WY mountains. The track of this low is more southerly than
previously expected, toward the Las Vegas area, which changes the
previously expected precipitation forecast over western and
central WY. Light snow is now expected across much of western WY
Thursday, moving into southwest and southern WY Thursday night
into Friday morning, with a slight chance across central WY. This
latest track is expected to keep the heavier precipitation to the
SW over Utah, and only bring a couple of inches so areas of SW WY.
As this low drop to northern AZ and NM Friday into Saturday, cold
NW flow will remain into Saturday as high pressure builds to the
west. The result for our area however is continued below normal
temps, with morning low between -10 and + 15 F. Global medium-
range models are all indicting another upper-level low dropping
out of British Columbia into the northern and central Rockies,
bringing yet another good chance of widespread snow and continued
cold temperatures. They are however disagreeing on the path of the
upper-level low center (to the east or west of WY), so details
are obviously quite muddled. Gusty southwest wind is also expected
to return to the typical locations starting on Thursday when the
mid-week low pressure system moves into the central Plains.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 330 PM MST Mon Jan 16 2023
West of the Divide...KBPI/KJAC/KPNA/KRKS Terminals.
A weak system begins to approach southwestern Wyoming this evening.
This will return lower ceilings and snow chances to terminals
overnight. Accordingly, have at least VCSH at all terminals by 06Z.
While this is a relatively low confidence event for terminal
impacts, KBPI, KPNA, and KRKS have the best chance at prevailing
light snow Tuesday morning, with KJAC seeing a better chance in the
afternoon.
East of the Divide...KCOD/KCPR/KLND/KRIW/KWRL Terminals.
Fog has more or less persisted through the day across central
Wyoming, and is expected to continue overnight. Accordingly,
IFR/LIFR conditions are likely to prevail at KLND and KRIW. KWRL
also has a chance at seeing some fog late tonight given there was
some noted there this morning. Additionally, a weak system will push
into southwestern Wyoming tonight, bringing a chance for light snow
impacts to terminals east of the Divide starting around 12Z Tuesday.
Most terminals will prevail light snow by late Tuesday morning.
Please see the Aviation Weather Center and/or CWSU ZDV and ZLC for
the latest information on icing and turbulence forecasts.
&&
.FIRE WEATHER...
Issued AT 1230 PM MST Mon Jan 16 2023
Latest snow producing system has moved to the northeast today,
leaving partly cloudy skies and areas of fog in the basins. The
western mountains picked up 4-8 inches of new snow with a dusting to
one inch elsewhere. Fairly seasonable mild day today with clouds
increasing from the southwest this afternoon. Snow showers will move
into SW WY around 3AM and spread northeast through the morning.
Light snow will spread into central WY during the middle of the day,
with some areas of moderate snow during the afternoon and evening.
Most locations will see some snow, with 1-3 inches in the central
and southern higher terrain and around 2 inches in the lower
elevations of central WY. Breezy SW wind today from southern into
central WY will weaken Tuesday morning, and switch to NNE late
Tuesday afternoon from central into southern WY, with gusts up to 30
mph. Snow continues Tuesday night into Wednesday morning to mainly
impact portions of central WY with snow showers ending Wednesday
afternoon. Slightly colder temps develop Wednesday night into
Thursday.
&&
.RIW WATCHES/WARNINGS/ADVISORIES...
Dense Fog Advisory until 5 AM MST Tuesday for WYZ016>018.
&&
$$
UPDATE...Hensley
SHORT TERM...McDonald
LONG TERM...McDonald
AVIATION...Myers
FIRE WEATHER...McDonald
Area Forecast Discussion
National Weather Service Shreveport LA
1001 PM CST Mon Jan 16 2023
...New UPDATE, SHORT TERM...
.UPDATE...
Issued at 950 PM CST Mon Jan 16 2023
Added patchy fog for a large portion of our area after midnight.
&&
.SHORT TERM...
(Tonight through Tuesday Night)
Issued at 950 PM CST Mon Jan 16 2023
Most of the showers have already worked out of the eastern half of
our cwa, but HRRR is showing a little more possible so we have
extend the early evening 3hr grid for 6hrs total until midnight.
After midnight, we may see a bit more fog cropping up with near
saturation already and light wind. Satellite shows most of the
denser mid and high clouds running along and south of I-20. A
better chance at seeing stars comes after midnight and with that
likely a little more fog too. 10 pm temps are mostly in the low to
mid 60s except for DeQueen just a few degrees away from the low
with some cold air drainage, but thinking they will hold close.
No changes needed to temps, but we did update obs and diurnal
trend. /24/
&&
.LONG TERM...
(Wednesday through next Sunday)
Issued at 154 PM CST Mon Jan 16 2023
Bottom Line up Front: Active long-term with severe weather possible
Wednesday afternoon. All modes of severe weather will be possible,
with damaging winds being the primary threat. Rain returns to the
region this weekend, which depending on trough ejection, could
result in another heavy rain scenario.
By Wednesday, a trough will begin to eject through the Plains, with
a surface low developing along the OK/CO border and moving east. The
catalyst for the severe weather will be a cold front that develops
ahead of this longwave trough, tied to the surface low. The
environment overhead of the current Slight Risk will be rich with
both shear and moisture, with surface dewpoints climbing into the
upper-60s by early afternoon. The biggest limiting factor on
Wednesday will be instability, as clouds and timing will keep
instability values below 1000 J/Kg. Regarding the tornado potential,
there is ample shear for these storms to work with, and forecast
wind profiles show some veering with height. However, that limited
instability won`t help tornado potential, and veer-back-veer wind
profiles may not help either. All that to say, tornadoes don`t look
like a slam dunk, but I`m certainly not going to say they won`t
happen. This is why right now, damaging winds look to be the main
threat with this severe weather.
Jumping straight into the weekend after a short break Thursday and
Friday, rain chances will increase once again associated with a
possible closed low moving east into the Midwest. This one is far
less certain, but current ejection and location of the closed low
could be favorable for a heavy rain scenario to develop across the
region. This one is only worth the mention, because recent trends
have the low speeding up, as opposed to slowing down, which would be
needed for the rain. Regardless, look for shower and thunderstorm
chances to return and remain through the weekend. /44/
&&
.AVIATION...
(00Z TAFS)
Issued at 542 PM CST Mon Jan 16 2023
For the ArkLaTex terminals, VFR becoming MVFR with some showers
ahead of a weak front in SE OK on approach, but this boundary only
touch and go overnight along our I-30 corridor. We will keep SW
sfc wind area wide through Tuesday 5-15KT. Additional showers and
thunderstorms are expected during Wednesday with the next stronger
cold with NW sfc winds arriving on Thursday and then NE winds for
Friday before our next system arrives w/ convection next Sat. /24/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 59 78 61 73 / 0 0 20 90
MLU 60 76 60 75 / 40 0 10 90
DEQ 47 72 53 69 / 0 0 40 70
TXK 56 75 59 70 / 10 0 30 80
ELD 57 73 56 69 / 10 0 20 100
TYR 55 78 61 72 / 0 0 30 70
GGG 56 78 60 71 / 0 0 20 80
LFK 58 79 62 73 / 10 0 20 90
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...None.
LA...None.
OK...None.
TX...None.
&&
$$
SHORT TERM...24
LONG TERM....44
AVIATION...24