Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/14/24
Area Forecast Discussion
National Weather Service Amarillo TX
555 PM CST Tue Feb 13 2024
...New AVIATION...
.SHORT TERM ...
(This evening through Wednesday night)
Issued at 245 PM CST Tue Feb 13 2024
Zonal flow will continue aloft in the short term forecast period.
Previous messaging remains on track as high temperatures at the
surface continue to rise, and winds will be increasing on
Wednesday in part due to a shortwave trough that transitions over
the area from the west. Highs will be in the upper 50`s and 60`s
today, with further 60`s in the forecast for Wednesday. Winds
should be from the west-southwest and increase to the 15-20 mph
range across central and southern portions of the Texas Panhandle
by tomorrow afternoon, and these breezy winds will continue until
the evening hours.
One notable addition to the forecast today is chance for freezing
fog in the eastern Texas Panhandle tonight. A few of the
convective allowing models like the HRRR and RAP suggest some fog
could develop in those areas late tonight through early tomorrow
morning, perhaps in the 12-8 AM Wednesday timeframe. Low level
moisture from our melting snow pack and calm surface winds could
support this proposition. Temperatures should also drop below
freezing early this morning, causing some surfaces to become slick
if fog settles in. However, coverage looks to be patchy, so some
localized area may be the only ones affected.
Rangel
&&
.LONG TERM ...
(Thursday through next Monday)
Issued at 245 PM CST Tue Feb 13 2024
Some minor changes in the upper level pattern may manifest as we
approach the weekend. Zonal flow will subside and allow for a
frontal passage across the CWA by Friday. As that upper level
trough fully develops, it will advance eastward across the CONUS.
From there an upper level ridge settles in and looks to remain in
place through next week.
Friday`s cold front will result in 40 degree highs in our northern
zones, while 50`s remain for the rest of the CWA. 40`s and lower
50`s should stay in place for Saturday`s highs as well. This
system should be dry as it moves through. Forecasted 700mb Theta-E
values suggest that the best chance for moisture advection will
be generated off of the lee side of the New Mexico mountain
ranges, but it won`t be carried very far. Therefore, non-
mentionable PoPs have been left in from the NBM, but if the
potential rises later this week as the forecast evolves the
northwestern combined Panhandles would have the best odds of
seeing some precipitation. Also on Friday, surface winds should
increase behind the cold front. Ranges between 15-25 mph from due
north can be expected, perhaps gusting to 40 mph at times.
As next week`s ridge settles in, surface winds will revert back
from the southwest and temperatures will rise back into the 60`s
and maybe even the 70`s if this dry, mundane pattern continues.
Rangel
&&
.AVIATION...
(00Z TAFS)
Issued at 542 PM CST Tue Feb 13 2024
For the 00Z TAFs, surface winds will increase and become gusty at
KDHT and KAMA late Wednesday morning into the afternoon hours as
the pressure gradient remains tight. Winds will be a bit lighter
at KGUY since that area will be in closer proximity to a weak
boundary expected to move through that location very late in this
forecast cycle with winds transitioning from the southwest to
the northwest. Overall, VFR conditions are expected to prevail at
KGUY, KDHT, and KAMA through late Wednesday afternoon.
02
&&
.PRELIMINARY POINT TEMPS/POPS...
Amarillo TX 29 64 30 61 / 0 0 0 0
Beaver OK 27 65 27 59 / 0 0 0 0
Boise City OK 24 61 25 58 / 0 0 0 0
Borger TX 31 67 30 63 / 0 0 0 0
Boys Ranch TX 26 65 27 65 / 0 0 0 0
Canyon TX 28 64 30 63 / 0 0 0 0
Clarendon TX 32 65 35 60 / 0 0 0 0
Dalhart TX 24 61 24 59 / 0 0 0 0
Guymon OK 25 64 26 59 / 0 0 0 0
Hereford TX 27 64 29 64 / 0 0 0 0
Lipscomb TX 29 67 30 60 / 0 0 0 0
Pampa TX 32 65 32 61 / 0 0 0 0
Shamrock TX 31 64 35 60 / 0 0 0 0
Wellington TX 31 65 36 60 / 0 0 0 0
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...None.
OK...None.
&&
$$
SHORT TERM...55
LONG TERM....55
AVIATION...02
Area Forecast Discussion
National Weather Service Grand Forks ND
650 PM CST Tue Feb 13 2024
.KEY MESSAGES...
- Brief period of light snow moves across the region from west
to east through the evening hours bringing a dusting of snow
accumulation and slick travel at times. &&
.UPDATE...
Issued at 650 PM CST Tue Feb 13 2024
Drizzle/freezing drizzle is being reported, but so far observed
impacts have been minimal in eastern ND and northwest MN as
temperatures have hovering near 32. This matches a small window
as indicated by the RAP/RAP soundings where ice aloft is
exiting the region, but low level saturation is just deep enough
before BL flow shifts west and RAP shows the transition to just
stratus/no precip. Where that is occurring drizzle already
seems to be ending, so based on the current timing this gives
about a 3-4 hour window for pockets of drizzle/freezing drizzle
and localized/slick impacts during the evening period (untreated
surfaces that cool enough this evening).
&&
.DISCUSSION...
Issued at 144 PM CST Tue Feb 13 2024
Current satellite indicates northwesterly flow aloft, with a upper
level wave moving across Saskatchewan and Manitoba. Front is
currently situated over the Devils Lake Basin, with an area of light
snow ahead of it. Signs of convective processes in the cloud
development in the James River Valley. Slight instability in the
warm air advection is helping to produce higher snowfall rates at
times. Clearing has been denoted ahead of the area of snow, and sky
coverage/temperatures where adjusted to take that into account.
Temperatures are getting into the mid 30s within the valley towards
northwestern Minnesota, with southerly flow at the surface. As the
front passes, cloud coverage is expected to increase, with winds
turning towards the west gusting up to 25kts at times.
Ensemble guidance is in good agreement that synoptic set up through
the next 7 days will be out of the northwest. The uncertainty lies
with the amplification of the ridge out in the western United States
and when its breaks down. 60% of guidance is indicating a flattening
of the ridge aloft as it shifts eastward. 40% of the other clusters
show the ridge sustaining northwesterly flow aloft over time, with
only a slight trend toward zonal flow by early next week.
Northwesterly flow aloft helps introduce upper level waves that
translates along the ridge.
The area of light snow is expected to translates eastward across the
forecast area throughout the afternoon and into the evening hours.
Observations have shown weaker intensity, with slight instability in
the southern extent (James River Valley). This may increase rates
briefly at times. Snow accumulations are expected to remain light,
with a dusting expected. There is an slight chance (10%) that an
isolated area were instability occurs that could bring up to an
inch. Slick travel may occur when snow is ongoing and accumulating
on surfaces. The area of snow should exit the Red River Valley this
evening, with confidence in its coverage and intensity trending
downward. CAMS have indicated this downward trend as instability and
synoptic lift weakens. The front thats co-located with the area of
light snow moves through shifting winds from the south to the west
this evening and overnight, with brief gusts up to 25kts in the
Devils Lake Basin.
Modeled soundings show a reemergence of low level saturation
lingering in the Red River Valley towards northwester Minnesota
during the 3am to 10am timeframe on Wednesday. Saturation is through
3km, with lingering synoptic lift from the main upper level wave.
This brings the slight chance (10%) for patchy fog within the Red
River Valley into northwestern Minnesota during the morning hours.
The one thing holding back the confidence is the winds being
sustained around 10kts, with gusts up to 20kts. This would hinder
the development of the fog during the morning hours. There is also
the slight chance (<10%) for patchy freezing drizzle to develop
during the same time frame. Confidence remains uncertain with patchy
freezing drizzle as main synoptic lift is still weak and may already
have shifted out of the area.
We will see a brief cool down as cold air advection wraps into the
region Thursday and Friday, with temperatures in the teens. As the
ridge flattens aloft this weekend and into next week, temperatures
will turn back toward the upper 20s to 30s for daytime highs.
Northwesterly flow aloft will still be present, and thus chances for
other systems to move through area are there but remain low in
confidence for timing, development, and track. One such system moves
north of the area Saturday and Sunday bringing chances (40%) for
wind gusts to reach up to 30kts.
&&
.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 650 PM CST Tue Feb 13 2024
Aviation impacts continue as light snow/flurries has already
pushed east of most terminals, however drizzle/freezing drizzle
has developed on the back side and may impact the TAF sites in
eastern ND and northwest MN through midnight. MVFR stratus is
likely to persist through much of the night (improvement at KDVL
first later tonight), and guidance is now showing this possibly
lingering into the daytime period Wednesday.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
&&
$$
UPDATE...DJR
DISCUSSION...Spender
AVIATION...DJR
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
655 PM CST Tue Feb 13 2024
.KEY MESSAGES...
- Burst of snow possible south of I-80/Kankakee River tonight
which could result in slick travel (~30% chance).
- Rain moves in Wednesday night with an expected transition
over to snow Thursday morning for areas north of I-88. Slushy
accumulations possible near the WI/IL state line.
- A period of snow possible late Thursday night into Friday,
with a chance (30-50%) of minor accumulations.
&&
.UPDATE...
Issued at 655 PM CST Tue Feb 13 2024
An early update to the forecast was made to shift the narrow
axis of snow tonight further to the south.
A weak surface low pressure system is located near Quincy,
Illinois, and is moving eastward toward central Illinois. A
narrow band of mid-level clouds (based near 6000 feet) is
evident on nighttime RGB microphysics imagery, with the
northward edge stretching from Pontiac, Illinois to Fowler,
Indiana and the southern edge stretching from Quincy, Illinois
to Indianapolis, Indiana. A similarly-narrow band of radar
echoes extends from Fort Madison, Iowa to Lincoln, Illinois,
near a region of weak frontogenesis and steep mid-level lapse
rates. With no surface observation platforms reporting
precipitation and the 00Z ILX RAOB still depicting a dry layer
from the surface to around 700mb, the radar echoes are
representative of virga thus far. However, top-down saturation
of the column appears quite attainable with time, which should
allow for snow to reach the ground at some point overnight.
With all of that said, the axis where saturation is favored is
where ongoing radar echoes (and virga) will "work" on the dry
air mass going forward. For this reason, the favored narrow axis
for snow overnight appears to be lining up somewhere between
Lincoln and Bloomington, Illinois and points east and west, just
to the south of our forecast area. As a result, felt it was
prudent to trim PoPs and snow accums in our local area to favor
areas just to our south.
Updated products have been sent.
Borchardt
&&
.DISCUSSION...
Issued at 300 PM CST Tue Feb 13 2024
Through Wednesday:
All is quiet weather-wise this afternoon with two regions of
cloudiness across far northeast Illinois as well as central
Illinois, with clear skies in between. Temperatures have warmed into
the upper 30s to lower 40s making for yet another above normal
February day.
Focus in the near term remains the potential for a narrow swath of
snowfall overnight south of I-80 and the Kankakee River Valley.
Increased cloudiness ahead of an approaching low-mid level
shortwave has expanded into central Illinois already this
afternoon. As the wave gets closer a shallow frontogenetical
circulation sets up overnight per RAP cross sections. Model
guidance has trended drier and slightly further south with the
axis of snowfall today. However, remain hesitant to make drastic
changes to the previous forecast due to it being not all that
uncommon for hi- res guidance to trend drier with these subtle
frontogenetically forced snowfall bands as we get closer to
onset time. Thus felt comfortable maintaining a narrow axis of
20-40% chances roughly between 11pm and 6am. Did nudge the
center of this axis south just a bit. If the dry air can be
overcome a quick coating of up to 1" could occur along a narrow
swath. It remains more likely that dry air in the lower levels
wins out but want to continue to message the potential. Those
south of an Ottawa to Kankakee to Rensselaer line will want to
check road conditions if traveling late tonight into early
Wednesday morning.
Winds return to a southerly director on Wednesday ahead of our
next weather system which should help temperatures warm into the
mid- upper 40s across the area.
Petr
Wednesday Night through Tuesday:
A mid-level wave over the northern Rockies tonight will amplify into
a compact shortwave trough and strengthening surface low across the
mid-Mississippi River Valley Wednesday night into Thursday morning.
Outside of some minor wobbles in the forecast surface low track,
guidance has been rather consistent in bringing the low across far
northern Illinois between I-88 and the WI state line. Deep-layer
forcing will be rather strong with the combination of a loosely
coupled upper jet streak pattern, potent mid-level trough, and
strong low-level isentropic ascent. Meanwhile, PWATs up to 0.7"
(>200% of normal) will feed into the system on 50-60 knot low-level
flow. With deep-layer 700-400 hPa lapse rates nearing 8C/km, precip
rates up to 0.25" per hour are possible for several hours around and
just north of the surface low. While not included with this forecast
update, some thunder cannot be ruled out in the elevated warm sector
across most of northern Illinois late Wednesday night.
Given the strong WAA ahead of the system, a vast majority of
guidance brings the wet-bulb freezing line north of the WI line by
late Wednesday evening, with precip expected to be all rain during
the nighttime hours. However, there remains a notable cluster of
guidance that struggles to bring the associated rain/snow line as
far north at the state line during the night. In the low chance (10-
20%) that precip remains primarily snow across extreme northern
Illinois, several inches of very wet snow would be possible late
night into mid-morning Thursday. However, overall expectations are
for precip to fall as primarily rain area-wide well into the night
before mixing with or briefly changing to wet snow for a few hours
toward daybreak and into mid-morning. In this scenario, slushy
accumulations of under an inch are possible for the northern tier of
IL counties. Impacts in this scenario should be minor as temps will
remain near or above freezing.
A deeper trough and colder airmass will dig SE toward the Great
Lakes region late week through the upcoming weekend. The amount of
phasing of a trough embedded across the northern High Plains and a
secondary Pacific-based trough remains unclear, with much of the
guidance suite favoring the Pacific trough outrunning the northern
trough on Friday. While a couple recent runs of the deterministic
GFS and a handful or so GEFS/EPS ensemble members do bring a more
phased and stronger system with the potential for impactful
accumulating snow in our area on Friday, overall guidance remains
less amplified across the mid-Mississippi River Valley and brushes
mainly the south half of the CWA with a period of light snow late
Thursday night into Friday morning.
Our three-week stretch of above normal temps will likely be broken
Friday and Saturday, but temps will still be in the seasonable range
for mid-February. With the core of arctic air progged to remain well
northeast of the area next week, we will remain on the slightly
above normal side of a persistent strong baroclinic zone across the
Great Lakes.
Kluber
&&
.AVIATION /00Z TAFS THROUGH 06Z THURSDAY/...
Issued at 551 PM CST Tue Feb 13 2024
There are no major aviation weather concerns through the 00Z TAF
period.
NW winds under 10 kt will go light later this evening. Direction
could be variable at times, but looks like predominantly easterly
going southerly overnight. Southerly winds under 10 kt can be
expected during the day on Wednesday shifting to SE in the evening.
Additionally, we should see VFR cigs move in later this evening.
They`ll scatter out overnight before more VFR cigs move over late
Wednesday afternoon.
Doom
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...None.
&&
$$
Visit us at weather.gov/chicago
Area Forecast Discussion
National Weather Service Salt Lake City UT
345 PM MST Tue Feb 13 2024
.SYNOPSIS...Several disturbances, generally weak, will cross through
the region through Friday, bringing periods of valley rain and
mountain snow, primarily for the northern Utah mountains. After a
brief break Saturday, an active and moist pattern redevelops
Sunday on into next week.
&&
.SHORT TERM (Through 12Z/5AM Thursday)...Forecast region remains
within zonal flow regime this afternoon, with mid/upper level
moisture advecting through and yielding some cloud cover
accordingly. Despite this mostly opaque cloud cover, temperatures
across the forecast region largely remain near to slightly above
normal.
Moving overnight into early Wednesday, a quick and fairly weak
shortwave brushes through the northern periphery of the forecast
region. Along with marginal slug of moisture, this feature will
help push a meager baroclinic zone through northern Utah (H7 temps
around -4C to -6C falling into roughly the -7C to -9C range).
Precipitation chances increase across the northern mountains as
early as late this evening, with lower elevation precipitation
seemingly largely confined near the aforementioned baroclinic
zone. CAM guidance continues to show a fairly large spread for
mountain water amounts, with the some sources such as the HRRR
showing as little as around 0.05" to 0.10" of liquid, and some
such as the NAMNest exceeding 1.00" in spots. Think the reality
will end up being on the more meager side given that the system as
a whole is pretty unimpressive, so current forecast reflects a
general 0.10" to 0.30" for the northern mountains. Some locally
higher amounts will be possible, with most CAM members
highlighting the Provo area mountains as the most likely place to
see some of those high numbers. With the current snow levels,
generally expecting a rain/snow mix for the Wasatch Front valleys,
with a bit more snow mixing in at higher benches. Snow levels
nearer the Idaho border will be low enough to keep mostly snow,
but even then anticipate any accumulations to be light. Overall,
main impact looks to be some light snow accumulation on any of the
more elevated routes through the northern mountains.
On Wednesday, the trough begins to exit the region. Flow shifts
to more of a warm air advection regime in advance of the next
system (see long term discussion), with precipitation largely
expected to more or less end with the exception of the far
northern Utah mountains and other areas nearer the Idaho border.
Despite lingering cloud cover, temperatures once again look to be
somewhat on the mild side Wednesday, coming in near to slightly
above climatological normal. Despite the quick break,
precipitation chances begin to climb once again overnight into
Thursday as the next system begins to push in.
.LONG TERM (After 12Z/5AM Thursday)...A storm system ejecting across
the PacNW region will move across the forecast area through the day
on Thursday, bringing a round of mixed valley precipitation and
mountain snowfall across the northern two-thirds of the forecast
area. An active weather pattern will persist through at least Friday
evening as a trailing wave moves across the norther portions of Utah
and southwest Wyoming which will help to maintain mountain snowfall
and colder valley temperatures. Numerical weather models have made a
notable upward trend in precipitation forecasts for the higher
terrain of northern Utah through this active period, with guidance
being well in support of snow water amounts ranging from 0.75 to
1.25 inches and snowfall amounts around 6 to 12 inches through
Friday evening. For valley areas expected precipitation amounts
range from ~0.05-0.1" in the Sanpete Valley, 0.1-0.25" along the
Wasatch Front, and 0.25-0.4" for the Wasatch Back and Cache Valley.
A large majority of this precipitation will occur through the first,
more significant, wave on Thursday into Friday, with generally
little additional accumulations through Friday. That said, portions
of the central and northern Wasatch will still see 1 to 3 inches of
snowfall contributed from the Friday wave. Bottom line, mountain
impacts will be greater the farther north you go in the forecast
area, with the highest amounts of snow forecast for the Bear River
range and the upper Cottonwood Canyons.
Valley precipitation type, particularly in the Cache Valley are a
bit more uncertain. By the time of precipitation onset in northern
Utah, which will occur during the mid-morning hours, overhead
temperatures will be too warm for valley snowfall. By the time
temperatures become cold enough for valley snow, a bulk of the
support for heavier precipitation will come to an end, allowing
things to transition to mountain focused precipitation. That said,
higher precipitation rates with overhead temperatures that are
borderline for valley snowfall may allow for precipitation to
rapidly transition to snowfall. As it stands, NBM shows a low (10%
or less) probability of seeing more than 1 inch of snowfall in the
Cache Valley and northern Wasatch Front, but these smaller scale
occurrences can often become over smoothed by guidance.
After these two consecutive waves later in the week, ridging will
reestablish temporarily on Saturday which will help to bring mostly
dry conditions. Shortly thereafter, an active pattern will resume
its barrage on the eastern Great Basin region. Model guidance is
showing generally high confidence in active weather remaining in
place through early next week, with a series of Pacific storm
systems anticipated to move through Utah and southwest Wyoming. As
of the 12Z model runs on February 13, guidance shows trends that
would favor valley rain and mountain snowfall. There is uncertainty
in how quickly this series of systems evolves, which will also
influence timing of precipitation, intensity, and the areal
extent... so continue to monitor upcoming forecasts.
&&
.AVIATION...KSLC...VFR conditions will be maintained over the KSLC
terminal through the remainder of the evening hours. Northwest winds
will prevail through around 03-04Z, becoming a light southerly flow
thereafter. Increasing cloud cover will spread over the terminal
through the overnight hours, with vicinity shower activity
increasing around 05Z. CIGs will remain above 6kft AGL through at
least 06Z, but will likely begin to obscure local terrain through
the remainder of the night.
.REST OF UTAH AND SOUTHWEST WYOMING...VFR conditions are expected
across the forecast area with increasing cloud cover through the
evening and overnight hours. An area of precipitation is expected to
spread across the northern two-thirds of the forecast area through
the overnight hours, with the biggest impacts expected to be tied to
the mountainous terrain. Obscuration of local topography is expected
across the northern half of Utah from about 06Z through 22Z.
&&
.SLC WATCHES/WARNINGS/ADVISORIES...
UT...None.
WY...None.
&&
$$
SHORT TERM...Warthen
LONG TERM...Webber
AVIATION...Webber
For more information from NOAA`s National Weather Service visit...
http://weather.gov/saltlakecity