Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/11/22
Area Forecast Discussion
National Weather Service La Crosse WI
558 PM CST Thu Feb 10 2022
.SHORT TERM...(This evening through Friday)
Issued at 127 PM CST Thu Feb 10 2022
Storm system tonight promising accumulating snow this evening, then
potential for snow/drizzle (freezing?) chances but minimal
accumulations overnight into Friday. Windy pre and post the system.
FORCERS: upper level shortwave trough still on track to drop from
northwest Canada and across the Upper Mississippi River Valley
overnight/Fri morning. Associated sfc low moves over the MN
arrowhead by this evening, pulling a warm front across the region
as it moves across the U.P. of Michigan during the overnight.
Strong, but somewhat narrow north-south running band of low level
warming ahead of the front, evident in 850 mb warm air advection
and upglide on the 280:295 K sfcs. This is maxed across the local
area between 00-06z. Narrow fgen band in the same region, focused
from 00-03z. Farther aloft, still some aid expected with the left
exit region of a 300 mb jet streak. The system`s cold front hangs
due west of the low and on track to drop south/southeast across
the local area Fri morning and should clear by 18z. Some fgen with
the boundary while low level lapse rates (1000:850 mb) remain
perky through the afternoon hours - suggesting some convective
snow showers will be possible. All in all, the system continues to
look essentially the same as it did a few days ago, with similar
timing.
SATURATION: no tap to southerly moisture, although some eastward
push of 850 mb moisture transport into the north-south running warm
front. Bufkit soundings and time/height x-sections show ample
saturation as the system moves in, but starts to shallow out
overnight as mid level drying knifes in - likely removing ice from
the cloud. Saturation deepens with the approach of the cold front,
with enough cold air also moving in to bring ice back into the cloud
layer.
TEMP: non-diurnal curve to the temp profile tonight as temps climb
post warm front this evening. Cold front then drops southward across
the forecast area mid morning Fri, with push of cold air in its
wake. Temps look to fall through the day. So, highs today will be at
midnight, with highs Friday likely just a few minutes after that.
Fri lows will be closer to midnight.
PCPN TYPES/AMOUNTS: snow will be the pcpn type with the
thermodynamics this evening, with highest accums still holding north
of I-94 (2-4"). Amounts generally an inch or less south of there.
The snow will likely last about 3 to 4 hours at most locations, with
rates nearing 1" per hour in the heaviest snow. Post the band, the
shallowing of the cloud depth removes ice, thus a change over to
liquid. However, sfc temps are also on the climb post the eastward
advancing warm front...so more likely drizzle rather than freezing.
Still, see a short window for freezing potential and that will have
to monitored. Snow showers could return early Friday morning as
cloud layer deepens/cooling a loft and cold front drops through.
Additional accums look minimal at this time.
Not seeing a need to expand current winter weather advisory at this
time.
WIND: breezy to blustery, depending on perspective. Southerly fetch
increasing through the afternoon/early evening as pressure gradient
tightens ahead of approaching warm front. Winds swing to the west
with warm front passage, then northwest later Fri morning as storm
system`s cold front drops through. Still looking sub advisory with
gusts generally under 40 mph expected. With relatively wet nature of
the expected snowfall, and existing snow pack having picked up water
over the last few days, blowing/drifting snow not expected to be an
issue.
.LONG TERM...(Saturday through Thursday)
Issued at 127 PM CST Thu Feb 10 2022
The surface low pressure shifts off to the Great Lakes on Saturday
following suit of the driving upper level trough. Lobes of mid level
vorticity advect on the nose of a subsequent upper level jet
streak, providing adequate forcing for possible light snow
Saturday afternoon. Otherwise, sensible weather concerns will be
colder temperatures as 925 mb temperatures reach -25C for much of
the forecast area according to the RAP (10.15Z). A surface high
pressure will result in light winds, keeping already low surface
temperatures, 5 to -5F, from reaching wind chill criteria at this
time. Have also increased precipitation chances for Sunday night
as as a slight kink advects along the northwest jet streak, and
isentropic upglide at the 270K surface hovers near 5 ubar/s
across central Wisconsin.
Temperatures return to seasonable Monday, max temperatures in the
20s, with a mid level ridge across the Mountain West and a slight
perturbation upstream over the Pacific Northwest as evident in
cluster analysis. Further cluster analyses breakdown in agreement
regarding the treatment of this perturbation on Tuesday. While mean
analysis places a positively tilted trough over the Southwest U.S.,
European-leaning clusters close this low while further disagreeing
on placement of the downstream ridge.
Longer term deterministic models (GFS/ECMWF) demonstrate this
disagreement in the upper level pattern and applicable sensible
weather differences. Irregardless of specific trough location, the
southerly placement of the shortwave energy results in tapping and
convergence of Gulf moisture into the Midwest U.S. through midweek.
Cluster QPF analysis places impacts from Texas to Maine, dependent
on cluster (i.e. trough locale). GEFS/GFS Integrated Vapor Transport
(IVT) exhibits an atmospheric river with 500/1200 kg /ms, 97th
percentile according to NAEFS/ENS... quite substantial moisture
transport.
The current forecast package places primary impacts to our forecast
area Thursday into Friday from the deformation band of a deepening
surface low traversing the Mid-Mississippi River Valley. Nailing out
any specific details at this time is futile, however, should be kept
an eye on as placement and direction of this substantial moisture
transport can result in a firehose of equally substantial impacts.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 553 PM CST Thu Feb 10 2022
A potent storm system will bring a wintry mix of precipitation and
strong winds to the TAF sites this evening with MVFR/patchy IFR
conditions. Bands of snow and a snow/sleet mix with some rain
mixed in or changing to drizzle. Additional precipitation possible
overnight, however looks to be transient. South winds 20 to 25kts
with gusts 30 to 40kts becoming southwest this evening. Did
include a period of low level wind shear due to the directional
sheer and wind of 50 to 55kts aloft. The winds shift to the west
and northwest 15 to 20kts with gusts 20 to 30kts after midnight.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...Winter Weather Advisory until 4 AM CST Friday for WIZ017.
MN...None.
IA...None.
&&
$$
SHORT TERM...Rieck
LONG TERM...JAR
AVIATION...Zapotocny
Area Forecast Discussion
National Weather Service Boise ID
842 PM MST Thu Feb 10 2022
.DISCUSSION...Many areas broke the inversion today and temps
warmed into the 50s and 60s. Models show higher surface pressure
Friday indicating cooling but the breakthrough today was not
forecast by yesterday`s models. HRRR came closest yesterday and
is showing about 5 degrees cooling Friday. Other models and our
forecast are cooling about 10 degrees. We hesitate to update as
the HRRR is an outlier. For now we will stay with our current
forecast but confidence is low.
&&
.AVIATION...Mostly VFR. Patchy MVFR/IFR in fog/low stratus is
expected late tonight and Friday morning in the KBKE and KMYL areas
and the Lower Treasure Valley (KEUL, KONO). Surface winds: variable
10 kt or less. Winds aloft at 10k feet MSL: northwest 20-40 kt.
Weekend Outlook...Mostly VFR with light winds. Patchy late night and
morning valley fog and stratus.
&&
.PREV DISCUSSION...
SHORT TERM...Tonight through Friday night...A continued ridge of
high pressure building in from the west will allow for dry and
mostly clear conditions through the weekend. Patchy fog and low
clouds are still expected in the lower Treasure Valley tonight and
Friday night as the temperature inversion continues in the
valleys. Normal or slightly above normal temperatures will
continue through the weekend as an extensive upper level trough
passes to our east and a slight shortwave trough passes to our
southwest, bringing slightly colder air into southwest Idaho and
southeast Oregon.
LONG TERM...Saturday through Thursday...An upper level trough
forming south of the Aleutians will deepen as it moves over the Gulf
of Alaska on Sunday. Models continue to show the system moving
inland over the Pacific Northwest on Monday, then diving south over
Nevada and California Monday night and Tuesday. Current timing has
precipitation spreading across southeast Oregon and southwest Idaho
from the north on Monday and ending in most areas by Tuesday
morning. Snow showers could continue over the mountains through
Tuesday evening. Precipitation totals are still uncertain, but
relatively light amounts are expected in the valleys, falling as a
mix of rain and snow. Wednesday and Thursday will be dry under
northwest flow aloft. Temperatures will be above normal in the
mountains and southeast Oregon and near normal in the valleys
through Monday. Temperatures will be near normal across the area
Tuesday through Thursday.
.AIR STAGNATION...A prolonged ridge of high pressure in our region
is leading to lower mixing heights and light surface winds. This
will continue hazy conditions with patchy fog and low clouds in
the lower Treasure Valley. This will last through the weekend,
until a cold front moves through Monday with stronger surface
winds and cooling aloft for better ventilation.
&&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...None.
OR...None.
&&
$$
www.weather.gov/Boise
www.facebook.com/NWSBoise
www.twitter.com/NWSBoise
DISCUSSION...LC
AVIATION.....BW
PREV SHORT TERM...SA
PREV LONG TERM....JT
AIR STAGNATION....LC
Area Forecast Discussion
National Weather Service Denver/Boulder CO
515 PM MST Thu Feb 10 2022
.SHORT TERM...(This evening through Friday)
Issued at 325 PM MST Thu Feb 10 2022
As expected, it`s mild across the plains this afternoon.
Temperatures today have generally hit the mid 50s to low 60s, with
the warmest temperatures observed from Boulder down into the
Denver metro. Even Greeley managed to make it into the upper 40s
to low 50s. Temperatures should remain mild this evening with
downslope winds continuing.
The first forecast challenge comes late this evening and
overnight as a mountain wave amplifies. Cross-barrier flow
increases to about 40kt after about 9pm tonight, with a robust
stable layer near mountain top. The HRRR has been advertising
gusts into the 70-85mph range above timberline in the Front Range,
while other CAMs are a little more muted with the high wind
signal. While the confidence in near-criteria wind gusts is high
(HREF mean winds near 70mph), I still don`t think we`ll see
widespread gusts above 75mph and have held off on any highlights.
Still, gusts into the 65-70mph range will cause a good amount of
blowing snow across the higher elevations tonight. A few gusts
will also likely make it into the wind prone areas of Boulder and
Jefferson counties, where a couple of gusts above 60 mph will be
possible.
Downslope flow will quickly be replaced by north-northeast winds
early tomorrow morning as a cold front arrives. Gradual moistening
of the low and mid-levels will take place through the morning and
much of the early afternoon, with cloud cover increasing through
the day. High-resolution guidance has reluctantly shifted towards
a wetter solution, with HREF Probability Matched Mean QPF now
showing a swath of 0.1-0.25 inches of liquid from BDU to DEN and
south into the Foothills/Palmer. Model soundings show shallow
upslope flow... extending up to about 750-700mb or so... and
coupled with synoptic scale ascent from a nearby jet, should be
enough for snow to develop in the mid-afternoon hours.
Temperatures are fairly marginal and the best lift is below the
DGZ, but we still could see a slick afternoon commute, especially
for those heading up into the Foothills/Mountains in the evening
hours. The current forecast made a minor bump up to snowfall
totals in the area but no highlights are planned at this point.
.LONG TERM...(Friday night through Thursday)
Issued at 325 PM MST Thu Feb 10 2022
We`ll see drying from the north early Friday evening, with snow
quickly becoming limited to areas from Denver west and south, and
then fading out in those areas by midnight. There`s sharp warm
advection and subsidence in mid levels after midnight which should
result in quick clearing, but then some clouds will develop as the
zone of warm advection lowers into the 600-500 mb layer where
there is some moisture by Saturday morning. The combination of
these clouds and the lack of wind on the plains may restrain the
warming a bit on Saturday, though areas in and near the mountains
where there will be some wind may fare better.
Sunday through Tuesday will be dry and warm as a flat ridge moves
over. Our forecast will remain nearer the warm side of the
guidance envelope with highs near 60 in Denver. We should see some
shallow valley inversions redeveloping, but starting from a fairly
warm place and with lots of sun, those areas will just not be as
warm as everywhere else. On Tuesday there may be some weak
cyclogenesis beginning somewhere in eastern Colorado, but with the
next system continuing to look a little slower, it doesn`t look
like there will be a real cold front until at least Tuesday night.
The model spread on the midweek system is not bad for this time
range. There`s pretty good agreement on a substantial trough
passing south of us on Wednesday or Thursday. Most of the
solutions currently show the strongest lift/best precipitation
south of us, but this could come back either through less digging
or a sharper trough that kicks the low out on a more south-to-
north path. We should get a deep frontal zone with moist upslope
flow which should be cold enough for snow at some point.
Uncertainty about when will limit our PoPs for now, but there will
likely be at least a little snow in the Wednesday-Thursday time
frame. This is a good candidate for a period of moderate snow, and
heavy snow is not out of the question though it`s appearing that
areas further south have better chances.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 515 PM MST Thu Feb 10 2022
VFR conditions through early Friday afternoon. Moderate westerly
winds have developed this afternoon with some gustiness from time
to time. Winds are expected to weaken at DEN and APA later this
evening and turn more towards drainage. A mountain wave will reach
BJC this evening with gusty westerly winds occurring sporadically
throughout the night. A cold front will arrive tomorrow morning
with a shift to gusty N/NE winds. A band of mid level
frontogenesis will move over the terminals around 18-19Z tomorrow
which will create light snow showers. Ceilings and visibility will
drop into MVFR at least and will likely drop into IFR at some
point during a heavier snow band.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...Hiris
LONG TERM...Gimmestad
AVIATION...Danielson
Area Forecast Discussion
National Weather Service Goodland KS
401 PM MST Thu Feb 10 2022
.SHORT TERM...(This evening through Saturday)
Issued at 305 PM MST Thu Feb 10 2022
At the start of the short term period, current RAP analysis shows
the CWA having a north-northwesterly flow aloft as the back part of
a trough is over the CWA. Satellite imagery shows some high clouds
traveling southward over a good portion of the CWA. Late Friday,
models show the upper air flow turning more northwesterly as the
trough starts to reorient itself. At the surface, dry conditions
expect to continue through the overnight hours with surface winds
turning northwesterly during the night around 10 to 15 kts.
Overnight lows on Thursday range between the upper 20s and middle
30s.
For Friday, forecast guidance shows the base of a reoriented upper
air trough over the CWA yielding a west-northwesterly flow aloft.
Closer to the surface, a cold front associated with a low pressure
system over the Great Lakes moves begins to move through the CWA
during the morning hours. Behind this front, the CWA looks to see
north-northwesterly winds that may gust up to between a possible 35-
40 kts with sustained winds possibly between 25 to 30 kts according
to forecast model soundings during the afternoon hours. While the
minimum RH values seen stay above 20 percent, there is a potential
for elevated fire weather with these winds as the GDFI looks to be
in the mid 30s for a good portion of the area. There looks to be a
chance for light snow associated with a shortwave disturbance
traveling through the flow aloft for the southwestern half of the
CWA though minimal accumulation is expected. Daytime highs for
Friday look to range between the lower 40s and lower 50s with
overnight lows in the middle teens to lower 20s. The western portion
of the CWA may see wind chill values in the single digits overnight
as well.
On Saturday, models show the back part of the upper air trough
moving over the CWA causing a northerly flow aloft through the
entire day. At the surface, there looks to be a surface low moving
southeast through central NE during the day which may cause some
breezy west-northwesterly winds during the afternoon around 15 kts.
Dry conditions are expected throughout the day. Saturday`s daytime
highs look to be in the middle 40s while overnight lows look to be
around the 20 degree mark.
.LONG TERM...(Friday night through Thursday)
Issued at 309 PM MST Thu Feb 10 2022
The first half of this time period will have rather benign
weather as a short wave ridge builds over the Plains ahead of the
next storm system. Highs will gradually warm each day through
Tuesday when the ridge is overhead. Relative humidity values will
approach threshold for fire weather concerns on Monday and Tuesday
for East Central CO.
During the latter half of the week the weather pattern will change
as a closed upper level low moves over the Southern Plains. The
last six model runs have been fairly consistent with placing a
trough over the Central Plains Thursday. However the disagreement
comes to what kind of trough will take shape. The data ranges from
an open wave to a closed low. Looking at the GFS and ECMWF model
ensemble data, there is a 30-40% chance for .1" or more of
precipitation occurring, with higher chances to the east of the
forecast area. This closed low is not too far south of the route
that would be best for producing heaving snow for the forecast area.
(Current forecast has rain changing to snow. Am doubtful there will
be much rain given the CAA occurring.) Accompanying the closed low
will be a strong cold front. Behind the front northerly winds will
be windy. This will be a dramatic change in the weather from earlier
in the week. Wind chills Thursday at sunrise will be in the single
digits, which is likely not cold enough. Am expecting lows
Wednesday night and highs Thursday to end up being cooler than the
current forecast.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 355 PM MST Thu Feb 10 2022
KGLD expects to see VFR conditions throughout the 00Z TAF period
beginning with west-southwesterly winds around 11 kts before
northwesterly LLWS of 45 kts at 2 kft begins at 04Z. At 05Z, KGLD
winds turn northwesterly around 13 kts with the LLWS increasing
to 50 kts. By 11Z, LLWS near KGLD ends as winds turn north-
northwesterly at 15 kts with a cold front passing through the
area. Winds for KGLD look to increase to 17G28 kts at 15Z and
speed up even more to 23G33 kts at 19Z.
KMCK looks to see VFR conditions as well during the 00Z TAF
period starting with west-southwesterly winds around 11 kts
before the winds turn westerly with westerly LLWS of 40 kts at 2
kft at 05Z. At 07Z, KMCK winds turn west-northwesterly around 13
kts followed by them slowing to 7 kts by 09Z. Winds at KMCK turn
north-northwesterly at 14Z with the cold front moving towards the
area then speed up to around 23G35 kts at 16Z.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...076
LONG TERM...JTL
AVIATION...076|
Area Forecast Discussion
National Weather Service Gray ME
1017 PM EST Thu Feb 10 2022
.SYNOPSIS...
Snow showers are gradually coming to an end over the mountains
tonight. Deep southwest flow develops Friday and continues into
Saturday, continuing warm temperatures across the region. A
strong cold front will cross the area late Saturday into Sunday
and return high temperatures in the region to the 20s. Low
pressure likely passes to our east and out to sea Sunday night
and early Monday. High pressure brings cool and dry weather to
the region early next week.
&&
.NEAR TERM /TONIGHT/...
1020 PM Update... Temperatures remain slow to cool tonight, so
have made another round of tweaks to bring lows up. Otherwise,
conditions are clearing south of the mountains while upsloping
showers and clouds cling to the mountains. Cleaned up PoP/sky
trends again to account for observations.
645 PM Update... The cold front has shipped east out of the
area this evening with showers coming to an end. Cyclonic flow
and upsloping will continue to support scattered showers near
the international border, but things are quieting down with a
westerly breeze developing. For the forecast... brought temps up
by a couple degrees overnight with mixing expected to continue
overnight in CAA. Also made a few tweaks to PoP and skies to
better align with observed trends.
Previously...
A surface cold front and a short wave aloft cross the region
this evening. Scattered light snow showers will continue across
the far north with possibly a heavier snow shower across the far
northern, higher terrain. This is supported by the latest 3 km
Nam, HRRR and radar trends in a steep lapse rate environment.
Snow squall parameters continue to run on the high side for
early this evening across the far north.
Latest observations, model soundings and GYX probability plots
continue to support the precipitation in the form of rain over
much of the rest of the forecast area. Surface temperatures
will continue to be very mild through the evening hours before
readings fall in a cold air advection environment. By late
tonight, temperatures will fall into the 20s allowing for
locally icy conditions on some untreated surfaces.
&&
.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
Clouds will gradually increase, thicken and lower on Friday as
a broad area of warm air advection enters the Northeast.
However, model soundings suggest the atmosphere will be
initially dry across the region so the precipitation will likely
hold off until Friday evening.
Low pressure passes by to our north Friday night. It will
continue to be on the mild side with above normal temperatures
and mainly scattered rain showers across the region. Some snow
shower activity can be expected over the northern, higher
terrain.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
Overview... Temperatures peak at the beginning of the extended
period before a cold front pushes through the area Saturday
afternoon. Another low pressure system approaches from the south on
Sunday bringing a dusting of snow to the coast and Southern NH. High
pressure takes over for early next week ahead of an approaching low
pressure system at the end of the week bringing the best chance of
widespread precip for the extended period.
Details... Southwesterly flow peaks temperatures Saturday ahead of a
cold front passing in the early afternoon. Highs are expected to
peak in the mid 40`s with southern and coastal areas approaching 50.
With dewpoints climbing into the 30`s in the warm sector,
conditions will be favorable for snow melt, especially in areas
south of the mountains. With the cold front passing, bringing in
cold air for Saturday night, the melt-water will refreeze and
could cause icy conditions in poor drainage areas.
Snow and rain showers will likely be making their way into the
mountains from the northwest over Saturday morning into the
afternoon ahead of the cold front. These showers will be light and
starting as snow. As temperatures climb through the morning, snow
will transition to rain and a rain/snow mix before the cold front
clears showers up, possibly changing some rain showers back to snow
before they stop.
Clouds will start to build back in Sunday as a low pressure system
approaches from the south offshore. Effects from this offshore
system will be mostly felt along the coast and Southern NH in the
form of heavy flurries to possibly and inch or two of snow Sunday
evening through Monday. Ensemble consensus over the last 24 hours
has been pointing to a low impact offshore event with low snowfall
totals.
High pressure takes over for early next week before a shortwave
trough moves northeast from the lower midwest at the end of the
week. For a day 8 storm, there is fairly good consensus between
deterministic and ensemble models of an elongated warm front
extending across the Great Lakes and St. Lawrence with a widespread
stratiform precip shield. The development and strength of this
system will be something to monitor as it comes closer, however
at the moment widespread precip seems likely.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
Short Term...Scattered rain and snow showers will continue
across the region through early this evening with the snow
limited to northern areas. Areas of MVFR conditions expected
with possibly a brief period of LIFR conditions in any heavier
snow showers across the high terrain in the north. Conditions
improve this evening from south to north to VFR. VFR conditions
expected on Friday, before more light precipitation enters the
region Friday night with MVFR conditions mainly confined to
northern areas.
Long Term...A cold front passing Sat could bring scattered SHRA/SHSN
to the north and mountains bringing possible MVFR conditions before
returning to VFR. The HIE area could experience periods of IFR or
lower conditions. Another chance of restrictions is possible in
coastal locations Sunday evening into Monday as a coastal low passes
offshore with snow showers along the coasts.
&&
.MARINE...
Short Term...SCA winds and seas persist overnight tonight behind
the front as winds veer to the west from the southwest. SCAs
conditions develop again Friday and Friday night over the outer
waters as a southwesterly gradient redevelops over the region.
Long Term...Marginal SCA conditions are possible Saturday with wind
gusts approaching 25-30 kts offshore. SCA conditions diminish Sunday
morning before returning late Sunday into Monday as a stronger low
pressure system passes offshore.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...Small Craft Advisory until 6 AM EST Saturday for ANZ150-
152>154.
Small Craft Advisory until 6 AM EST Friday for ANZ151.
&&
$$
UPDATE...Casey
NEAR/SHORT TERM...Cannon
LONG TERM...Thunberg
Area Forecast Discussion...UPDATED
National Weather Service Jackson MS
933 PM CST Thu Feb 10 2022
.UPDATE...
Updated for evening discussion.
&&
.DISCUSSION...
Given the dry air mass still in place, the MinT`s were nudged
slightly cooler tonight. Temperatures should generally remain
above freezing tonight, although a few patches of frost could
develop in a few spots where winds are lightest. Looking at
observational trends over the last few days, prime heating and
mixing conditions have seen deep mixing conditions dry out dew
points to the low end of guidance each day, as well as boost winds
and temps a little over guidance during the peak mixing period.
Even with the lower level flow taking on a little more southerly
direction, mid-level trajectories will be from a more westerly
direction and help to advect in warm, dry air from the Southern
High Plains. MaxT`s Friday should be a few degrees warmer than
today, with dew points only seeing a slight uptick. Blended a mix
of latest RAP and HRRR dew points through the afternoon tomorrow,
which yields minimum relative humidity values once again around
25% (give or take). With an approaching cold front, a stronger
pressure gradient will help keep winds breezier tomorrow. The
combined humidity and wind values through the ArkLaMiss Delta will
approach critical fire weather thresholds for our area, and
additional messaging may be needed in the Hazardous Weather
Outlook and fire wx products for tomorrow. We`ll evaluate the
latest suite of 00Z guidance, but suffice to say conditions will
be dry and windy tomorrow. Several parish and county burn bans
were added in the region today, and any activities that produce
flames or sparks near vegetation are discouraged. /NF/
Prior discussion below:
Tonight through Friday:
Temperatures tonight will be notably warmer with winds increasing
and becoming southwesterly. Lows tonight fall into the lower 40s
F, about 10 degrees warmer than this morning. Behind a departing
shortwave trough, winds aloft will remain northwesterly and
overall the sensible weather will remain similar on Friday as
compared to today. Dry air and high pressure will be in control
and temperatures will warm quickly into the lower 70s F for most.
While southerly winds may help keep our dewpoints into the 30s F
as opposed to the 20s F seen in previous days, the additional wind
and warmer temperatures will serve to continue hazardous fire
weather conditions. The Hazardous Weather Outlook (HWO) product
will continue to advertise this risk with an Elevated (2/4) risk
for increased wildfire danger. Winds will likely be gusty Friday,
and some areas of the Mississippi River Delta could see wind gusts
between 20-25 mph with 15-20 mph gusts possible elsewhere. /86/
Friday night through Wednesday:
Come Friday evening a dry cold front will be approaching our CWA
from the northwest. This cold front will be driven by a deepening
upper level trough diving through the Plains. The cold front is
expected to move into our northwest most zones prior to sunrise
Saturday morning and be nearly along the Natchez Trace by noon.
Although the cold front will be dry, a potent northern stream
shortwave helping to deepen the upper level trough will try to
squeeze out some anafrontal precipitation across our western zones
by late morning. There remains differences in the models with the
amount of precipitation if any that will fall in our CWA. Very
cold air aloft will be moving over our CWA while surface
temperatures drop and drier air moves into our CWA in the wake of
the cold front. The cold front is expected to push southeast of
our CWA by evening and the precipitation is expected to remain
generally along and north of the Natchez Trace. There will be a
brief period early Saturday evening in our northeast where the
light rain may mix with light snow before tapering off but no
accumulations are expected. Temperatures will fall in the wake of
the front during the day Saturday and continue Saturday night with
morning lows back below freezing areawide Sunday morning. Dry
weather is expected to continue through Tuesday night. Cooler than
normal temperatures are expected Saturday night through Monday
night but temperatures will warm back above normal Tuesday and
continue above normal through Wednesday ahead of the next low
pressure system that will bring a chance of rain by Wednesday
afternoon. /22/
&&
.AVIATION...
00Z TAF discussion:
VFR conditions should prevail through the period at all TAF sites,
however some brief reductions in visibility from smoke or haze
cannot be ruled out due to some fires burning in the region.
Light southwesterly winds before 12Z Friday will increase to
around 10-15 kts with gusts of 20-25 kts by 15Z Friday. /NF/
&&
.PRELIMINARY POINT TEMPS/POPS...
Jackson 39 73 42 59 / 0 0 0 11
Meridian 38 73 43 62 / 0 0 0 6
Vicksburg 39 74 43 57 / 0 0 0 17
Hattiesburg 37 72 41 68 / 0 0 0 5
Natchez 39 73 42 60 / 0 0 0 11
Greenville 40 73 42 50 / 0 0 0 19
Greenwood 40 73 43 52 / 0 0 0 17
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...None.
LA...None.
AR...None.
&&
$$
NF/22/LP
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
942 PM CST Thu Feb 10 2022
.UPDATE...
Issued at 940 PM CST Thu Feb 10 2022
Overall, the forecast remains on track this evening with the axis
of warm advective precipitation approaching the area from the
northwest. Did nudge down the total QPF thanks to lingering dry
air in the lower levels out ahead of it which has kept the area of
precipitation a bit more splotchy. Evening 00Z model guidance
has also depicted a shorter window for the burst of snow before
things transition fully to rain, which could act to limit our
accumulations. Am hesitant to make big changes to the timing of
the full change over to rain since wet bulbing could help keep
temps down a bit longer. Thus, the forecast snowfall amounts were
nudged down mainly due to the lowering of QPF. We are still
expecting a quick burst of snow during the 12am-3am timeframe
with associated visibility reductions and slushy accumulations up
to 0.5" and locally to 1". Temperatures will also be on the
increase through the remainder of the overnight hours as strong
warm advection continues with southwest winds gusting to 30-35mph.
This will in turn begin melting any snow that does accumulate and
help limit impacts during the Friday morning commute. There may
still be patchy slick spots out there though, especially on
untreated roadways.
No changes were made for the daylight hours Friday with a period
of drizzle/light rain possible in the morning with snow showers
developing behind the cold front late afternoon into the evening.
Petr
&&
.SHORT TERM...
Issued at 255 PM CST Thu Feb 10 2022
Through Friday night...
The primary concerns for the short term forecast are:
* High confidence in a 2-3 hour period of wet snow between 10 PM
and 3 AM tonight, with an inch plus of quick accumulation in
parts of northern Illinois; impacts expected to diminish quickly
into daybreak with rising temperatures
* Mild to start Friday with areas of drizzle and spotty rain
showers through early afternoon Friday, then scattered snow
showers developing mid to late afternoon into evening, which
could briefly but sharply reduce visibility and lead to spotty
light accumulation
The digging, closed upper low of interest for tonight is moving
into northern Minnesota as of this afternoon. It`s warm advection
wing extends to its south and has consistently been producing a
fairly narrow corridor of snow throughout today as it shifts east-
southeast. Little will change with the character of this wave as
it progresses into the central Great Lakes, so expecting this snow
to translate over the area. The strongest forcing for ascent
under the left exit region of the digging upper jet, as well as
the most robust saturated isentropic ascent, are focused north of
I-80. While it will snow south, the best chance for 1+ inch
accumulations is north, including Chicago. Snowfall rates look to
be stout within this, aided by instability aloft as shown by
850-600 mb lapse rates of 7.5 C/km on forecast soundings. Observed
radar reflectivity and visibility upstream confirm this, with
several Upper Midwest sites having dropped below 1 SM in the snow,
and even a few 1/4SM observations. Finally, this snow will occur
concurrently with gusty southwest winds, induced by 9 mb/6 hr
pressure falls over the area by midnight. This will further assist
in briefly but sharply reducing visibility.
The duration and the timing of occurrence of this both help to
limit the degree of impacts. With the snow likely having ended or
transitioned to drizzle/light rain by 3 AM or shortly after, along
with temperatures and dew points rising above freezing, roads are
much more favored to be lightly slush covered than icy. That also
may be more secondary roads than primary ones given a few hours
between end of snow and the commute time, allowing snow removal
operations to get ahead of things. If this was four hours earlier
or later, an impact-based Winter Weather Advisory would be
strongly considered. But with the timing, will message it into
this evening, and have issued an SPS.
The forecast area will remain under cyclonic flow into Friday,
with another short wave digging and phasing into the main wave,
causing a further deepening of the system as it moves into the
eastern Great Lakes. The warm sector will prevail over the area
during the morning into early afternoon, with temperatures likely
to peak at 40 in many places. Morning pockets of drizzle,
especially early, and spotty light rain showers are expected.
These showers may be persist for a few hours along/east of I-57,
where the upper jet forcing looks to linger longer.
During the afternoon as the next wave digs in, the cold front will
sweep into the forecast area. Low-level lapse rates will steepen
markedly within the cold air advection regime, and some shallow
CAPE (mainly less than 30 J/kg) is forecast to develop on the RAP
and HRRR. Convection allowing models (CAMs) do indicate scattered
convective echoes gradually developing during the latter half of
the afternoon along/near the cold front. Conceptually this makes
sense with the mid-level vorticity maximum also overhead. With
thermal profiles quickly cooling, there would be an increasing
propensity for some of these showers to be snow showers. While
temperatures will be above freezing at the surface, the convective
nature of such showers could result in brief quick accumulation of
a few tenths under these showers, as well as sharply reduced
visibility. Confidence is not that high yet on what coverage of
these will be, and if it will align just right thermally for snow
showers given how mild it will start on Friday. Confidence is high
though in northwest winds gusting to 25 to 35 mph behind the front.
The incoming cold air will send wind chills down to the single
digits above zero by late Friday evening, and to below zero by
daybreak Saturday. In addition, lake effect snow showers should
develop into northwest Indiana, especially Porter County, by
overnight Friday night. These are likely to be of a mainly
disorganized nature, but still be able to produce accumulation of
up an inch or so by daybreak Saturday.
MTF
&&
.LONG TERM...
Issued at 152 PM CST Thu Feb 10 2022
Saturday through Thursday...
Lake effect snow may linger across Porter County in northwest IN
on Saturday morning. A quick moving area of high pressure will
move south of the area Saturday afternoon into Saturday evening,
allowing winds to turn more westerly during the day, which should
push any remaining lake effect snow east of the area by Saturday
afternoon. Saturday looking rather chilly with highs likely
struggling to reach the lower 20s.
A fast moving clipper system will move across the area Sunday
morning and the current track of this system may bring most of the
snow southwest of the area, where a narrow band of perhaps up to
an inch of snow is possible. Given the current track, opted to
only include low chance pops for Sunday morning, but this time
period will need to be monitored with higher pops possible,
especially across the southern cwa. As this system departs Sunday
afternoon, there is another potential for lake effect snow showers
Sunday afternoon, possibly lingering into Sunday evening across
northwest IN.
Dry weather is expected Monday and Tuesday with moderating temps
and then a storm system looks to affect the region during the
middle of next week. Still several days away and too early for
specifics. But the current consensus track would bring
accumulating snow near the northern cwa with a possible mix in
part of the area, on the back side. Prior to any winter precip,
there will be the potential for rain and perhaps a period of
moderate to heavy rain as precipitable water values are into the
one inch range by Wednesday night. Made no changes to the blended
forecast and the only change from those was to lower pops on
Wednesday, which seems in line with the 12z guidance showing any
precipitation on Wednesday looking rather light. Strong winds are
likely during this period as well and if they are southerly, this
may allow dewpoints to reach well into the 40s, which would
quickly melt the existing snowpack across the southern two thirds
of the area. That combined with any heavy rain would increase the
risk of flooding, especially localized ice jam flooding on rivers
if there were quick rises. cms
&&
.AVIATION...
For the 00Z TAFs...
Aviation Forecast Concerns:
* Strong southwest winds developing with gusts around 30 kt
overnight. LLWS conditions as well, with WSW winds to 55 kts at
2000` AGL overnight.
* Short period of snow between 05-09Z with IFR visibilities
likely before changing to drizzle which lingers with MVFR
ceilings into Friday morning.
* Cold front pushes across the area Friday afternoon, winds
shifting west with gusting AOA 30 kts again along with a period
of convective snow showers into Friday evening.
Sub-1000 mb low pressure along the MN/MT border will move
southeast across the northern Great Lakes through the forecast
period. Strong southwesterly low level flow will develop across
the terminals this evening in response to strong pressure falls
associated with the low. Surface winds may gust near 30 kts during
the late evening/early overnight hours, with LLWS conditions as
well with winds at around 2000` AGL increasing to around 55 kts.
Within the strong flow and associated warm advection, a band of
snow will spread across the area during the late evening,
persisting a few hours with IFR visibilities and some quick
accumulations possible. Strong warm advection will eventually
change precipitation over to rain, and will quickly diminish to
drizzle which will linger into Friday morning along with MVFR
ceilings. MVFR ceilings may scatter for a time during the day
Friday, though confidence in this is low at this time.
As the low tracks east on Friday, its trailing cold front will
push east across the terminals during the afternoon. This will
produce a wind shift to the west, along with a renewed increase in
wind speeds/gusts to around 30 kt again later in the day.
Scattered convective snow showers and MVFR ceilings also appear
likely, especially toward 00Z as the column cools and low level
lapse rates steepen.
Ratzer
&&
.MARINE...
Issued at 255 PM CST Thu Feb 10 2022
With the approach of a strong disturbance, southwest winds will
sharply increase this evening peaking during the overnight. Gales
remain likely on the Illinois nearshore and cannot rule out a few
even near 40 kt. This will be concurrent to a 2-3 period of
heavier snow, so visibility will drop sharply in the nearshore.
For the Indiana nearshore, some overnight gale force gusts may
occur a few miles offshore.
On Friday late afternoon, a strong cold front will move across
southern Lake Michigan. The northwest winds behind this will gust
to 30 kt and a few gale force gusts are possible late the day
into Friday evening for both the Illinois and Indiana nearshores.
Waves along the Indiana nearshore (which is now more largely ice
free) will build up to 10 ft and occasionally higher.
MTF
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...Gale Warning...IL nearshore waters until 6 AM Friday.
Small Craft Advisory...IN nearshore waters until 3 PM Saturday.
&&
$$
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Area Forecast Discussion
National Weather Service Marquette MI
746 PM EST Thu Feb 10 2022
.SHORT TERM...(This evening through Friday)
Issued at 344 PM EST THU FEB 10 2022
Lake effect snow showers have tapered off across the northwest wind
snow belts over the last few hours. And, there has been some
clearing across the southern portions of Upper Michigan. But, that
will quickly fill in as focus turns to the next Clipper system this
evening. HRRR/RAP analysis this afternoon is trending toward light
snow entering the far western counties over the next few hours,
which correlates well with the current radar mosaic. By 00Z, snow
chances will spread into central portions of the UP with categorical
Pops over the western counties. In addition, southerly winds will
ramp up this evening with sustained speeds in the 10 to 15 mph
range, gusting to 30 mph. Currently, temperatures across the
forecast area are generally in the low to mid 20s.
.LONG TERM...(Tonight through Wednesday night)
Issued at 324 PM EST THU FEB 10 2022
Tonight, a clipper system with a strong mid-level fgen band out
ahead of it will dive southeastward through the Boundary Waters and
across Lake Superior. Models show a few hours of strong isentropic
lift on the 285 K surface (around 700-800 mb) this evening. Most
areas should see around 0.15-0.25" of QPF with SLRs around 15:1
leading to 2-4" of snow. One exception will be right along the Lake
Superior shoreline where strong southerly downslope winds will eat
away at some of precip, keeping them right around 2" or just under.
The other exception will be in Schoolcraft County, particularly in
and around Manistique, where southerly flow enhanced by Lake
Michigan moisture/instability will boost QPF to nearly 0.5" per the
LPMM of the SPC HREF QPF. Therefore, could see snow totals flirt
with warning criteria down there, especially if the 12z HRRR (which
was a significant wet outlier) verified. However, the plan right now
is to maintain the ongoing Winter Weather Advisory, with a possible
upgrade to warning not off the table.
Tomorrow, as colder air rushes in behind the system, northerly flow
lake effect snow will expand across the north wind snow belts
through the morning and afternoon. There could be a short window for
upslope-driven freezing drizzle before colder air returns, but
because any possible FZDZ would be falling on top of a few inches of
fresh snow, it is not expected to be impactful. Once the cold air
arrives, strong northerly/upslope flow along with hefty lake-based
instability (sfc-850 mb delta T`s around 20 C) and several hours of
deep moisture should lead to a period of moderate to heavy
upslope/lake effect snow in the afternoon and evening, mostly
clinging to the higher terrain. Also of note is that based on the
model sfc T fields, it appears most if not all CAMs are overdoing
the coverage of ice on Lake Superior east of the Keweenaw Peninsula,
which likely translates to an underestimate in moisture and sensible
heat flux and thus could argue for going even higher on QPF. WPC QPF
was already near or above the 75th percentile of guidance in the
north wind lake effect belts, so did not add much or anything at all
to it, but will note that a further upward adjustment is possible.
Additional snow amounts from lake effect/upslope snow (from 12z Fri
to 12z Sat) should end up in the 4-8" range in the north wind snow
belts, with a few localized amounts up to 10" possible. Blowing snow
will also be a concern with the strong north wind, as will reduced
visibility as the column cools so much that dendritic growth ends
and flake sizes become much smaller. Therefore, have expanded the
Winter Weather Advisory to cover the entire CWA. Amounts will be
marginal for reaching advisory criteria in Iron, Dickinson, and
Menominee Counties where there will be little if any lake effect
snow, but the intensity of the snow tonight along the blowing snow
tomorrow justifies it.
Lake effect showers will last into Saturday morning, although lesser
coverage than Friday night and evening. These northerly wind
snowbelt showers warranted changes from the National Blend through
the weekend with a more scattered nature likely. A clipper passing
mainly west of the U.P. Saturday night will shift winds back to
northerly. Those northerly winds, cold and semi-moist low levels
could create another round of northerly wind snowbelt LES showers
into Sunday. While some scattered LES showers are possible Saturday
night, much of the region remains on track to experience some well
sub zero low temperatures. Interior west parts of the U.P. and
other higher terrain basins remain on track for lows down to
fifteen below, and more towards zero closer to the shorelines.
Temperatures slowly warm into the start of next week as two more
progressive shortwaves could pass over the area from current progs.
Ensemble guidance supports the west-northwesterly wind snowbelt lake
effect showers in the wake of the Monday shortwave with some manual
PoP adjustments made away from the NBM guidance. These would keep
the northwesterly mid-level flow across the region for the most
part. There are early indications of stronger southerly flow by mid-
next week leading to a potential warm-up again.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 701 PM EST THU FEB 10 2022
Snow has already moved into the western U.P. early this evening in
advance of the approaching Clipper system over northern MN.
Conditions have already lowered to IFR at IWD in snow and expect
the same to occur at CMX between 01-02Zz and at SAW btwn 02-03Z.
Look for improvement to MVFR conditions at IWD and SAW mainly
after 09Z tonight as snow tapers off from west to east as the
surface low moves over the area. Cold air pushing in Friday in the
wake of the system will generate north winds lake effect snow
bands. The snow bands and blowing snow caused by gusty north winds
to 30 knots or higher will lower categories down to IFR or LIFR
beginning late Friday morning at IWD and CMX and by early Fri
afternoon at SAW. The best chance for sustained LIFR conditions
will be at IWD and CMX.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 324 PM EST THU FEB 10 2022
Southerly gales tonight to 35 knots across the central part of Lake
Superior. Winds shift northerly Friday morning. The strongest winds
from Friday afternoon through night will see some storm force
gusts to 50 knots across the central part of the lake and strong
gales to 45 knots elsewhere. Freezing spray will continue to come
into play tonight, and again Friday afternoon through Saturday
morning. Northerly winds decrease Saturday then shift to
southwesterly Sunday. Northwesterly winds around 20 knots are
possible again by Monday.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
Winter Weather Advisory until 7 AM EST /6 AM CST/ Saturday for
MIZ001>007-009-084-085.
Winter Weather Advisory until 7 AM EST /6 AM CST/ Friday for
MIZ010>014.
Lake Superior...
Gale Warning until 7 AM EST Saturday for LSZ243>251-264>267.
Gale Warning from 7 AM EST /6 AM CST/ Friday to 1 AM EST
/midnight CST/ Saturday for LSZ162-240>242-263.
Lake Michigan...
Gale Warning from 4 PM Friday to 1 AM EST Saturday for LMZ221-
248-250.
&&
$$
SHORT TERM...TDUD
LONG TERM...RC/NLY
AVIATION...Voss
MARINE...NLY
Area Forecast Discussion
National Weather Service Pocatello ID
832 PM MST Thu Feb 10 2022
.UPDATE...
Updated forecast to issue a dens fog advisory for most of the
Snake Plain into the Teton Valley through 10 am Friday. Most
models show visibilities tanking throughout the night in these
areas as winds weaken and gradually turn downvalley. Expect to see
a rapid expansion and lowering of the low stratus area that is
present this evening across the upper Snake Plain. Visibilities
less than 1 mile and lower than 1/4 mile are likely at times
tonight. Models are a little uncertain if the stratus/fog will
make it to I-84 or not, but thinking is that with the downvalley
winds that they will make it although it could be late in the
night.
13
&&
.PREV DISCUSSION... /issued 156 PM MST Thu Feb 10 2022/
SHORT TERM...Tonight through Friday night. Satellite imagery
shows weak upper shortwave passing through East Idaho, leaving
behind low stratus/fog across many low elevation areas. Surface
based inversions look to remain well entrenched across the region,
with some 20-30 degree difference between valley locations and
some higher elevation observations in the central mountains.
Expect these conditions to continue under influence of high
pressure through the short term and into the weekend. DMH
LONG TERM...Saturday through next Thursday. It appears the
deterministic models are backing off on timing of the onset of
precipitation Monday until later in the day. We continue to see a
split flow developing with a cutoff low headed into southern
California. This is a bit further west than previous runs have been
showing, and explains the slower timing of onset of precip. Ensemble
clusters show varying trough split scenarios, with about a quarter
of the ensemble members clustering around the cutoff in southern CA.
The majority of the members favor a cutoff over NV/UT Tuesday. The
result on the forecast is that we`re looking a little drier for the
Mon-Wed period. With a split flow, models maintain most of the
moisture in the vicinity of the cutoff low. Otherwise, temperatures
should be approaching climate normals in the long term periods. A
northwest flow pattern resumes as the upper trough exits to the east
Wednesday or Wednesday night. Hinsberger
AVIATION...A dry northwesterly flow prevails over the region. This
bodes well for KSUN, which is expected to remain VFR through the
period. There is a lot of uncertainty for the other terminals
though. Current satellite imagery shows some upper level clouds
obscuring the fog/stratus layer, so it`s hard to determine the
extent of it. HRRR and HREF are suggesting widespread fog/stratus
with HREF spreading LIFR conditions all through the Snake Plain.
Guidance has generally been overdoing the fog this week, but if mid
and upper level clouds clear, it may indeed drop to LIFR. Again,
uncertainty is high with respect to the flight categories, and I
anticipate we`ll cig/vis fluctuating through the period.
Hinsberger
&&
.PIH WATCHES/WARNINGS/ADVISORIES...
Dense Fog Advisory until 10 AM MST Friday for IDZ051>055-065-068.
&&
$$
Area Forecast Discussion
National Weather Service Pueblo CO
645 PM MST Thu Feb 10 2022
.UPDATE...
Issued at 637 PM MST Thu Feb 10 2022
Have updated the forecast to bump up snow totals across the Pikes
Peak region and eastern mtns/I-25 corridor from late tomorrow and
tomorrow night. For some reason, the HRRR looks UNDERdone wrt
snowfall amounts and have leaned more to a blend of NBM with a
heavier weight to the NAMnest and 90% NBM qpf (with a bit of human
massaging). Overall accums went up an inch or two especially in
the normally snowier areas. Also, I believe our temps up in the
Pikes Peak region were to warm tomorrow afternoon and have bumped
these down. /Hodanish
&&
.SHORT TERM...(This evening through Friday)
Issued at 325 PM MST Thu Feb 10 2022
High level cloudiness was spreading over the area this afternoon
ahead of nrn Rockies short wave, while temperatures have responded
to increased mixing and warmer mid-levels, with readings as warm as
60f in a few spots across the plains. Tonight, should see slightly
milder min temps at many locations as breezy downslope winds persist
and occasional bouts of mid/high level cloudiness move through. Some
mixed messages on fog potential in the San Luis Valley overnight
among various short range models, though suspect enough cloud cover
will be overhead to keep any fog rather patchy and short-lived. On
Friday, cold front comes through the plains in the morning, bringing
gusty north winds and cooler temperatures to most locations along
and east of the mountains. Clouds will thicken and lower during the
afternoon as low level flow takes on an easterly component, though
models aren`t particularly enthused about precip chances prior to
00z, as upward motion associated with the upper trough will be slow
to arrive. As a result, trimmed back srn extent of snowfall Fri
afternoon, and delayed the onset or precipitation by just a couple
hrs. Best bet for snow during the daytime hrs will be over the
central mountains and the Pikes Peak/Palmer Divide, where at least
some light snow will develop after 3 pm.
.LONG TERM...(Friday night through Thursday)
Issued at 325 PM MST Thu Feb 10 2022
Key Messages:
1) Light snow likely along the eastern mountains Friday night.
2) Another storm system will possibly impact the southern Colorado
region mid week next week, bringing increased precipitation chances
and cooler temperatures.
Friday Night... During the overnight hours, a short wave trough will
be pushing southward across the eastern part of Colorado. As this
feature quickly pushes southward, synoptic support will increase
across the region, which will aid in the development of light
stratiform precipitation. Winds aloft will also increase, and
orographics will become stronger, especially over the eastern
mountains. Surface winds behind a cold front will be mostly
northerly, though immediately along west of the I25 corridor winds
will have an easterly component, and weak surface upsloping will
materialize. With this, light snow is expected to develop/continue
along the eastern mountains overnight. Pockets of light snow are
possible across the eastern plains as well given the synoptic
support moving across the area. The eastern mountains will see the
most snow, with snow totals 1-1.5 inches. As for the eastern
plains, snow totals will likely be less than 1 inch. As this
feature exits the region by Saturday morning though, precipitation
will decrease from north to south. Elsewhere across the forecast
area though, precipitation chances will remain low.
Saturday - Tuesday... The majority of the long term period will stay
quiet weather wise. The GEFS and EPS ensemble models are in strong
agreement that a ridge of high pressure will develop over the
western US and expand over Colorado. The strong agreement between
the models leads to greater confidence in the overall forecast.
Given the ridge, synoptic descent will overspread southern Colorado,
and will allow for a stretch of quiet days. Precipitation chances
will remain low for the forecast area, with precipitation chances
less than 10%. Temperatures will also begin a warming trend, with
Saturday near to slightly above average, and then Sunday through
Tuesday above average for all of southern Colorado. Temperatures
will likely warm to 10-15F above average for this time of year.
Wednesday - Thursday... Near the end of the long term period, a
pattern shift appears likely, bringing more active weather to
southern Colorado. The ensemble models remain in agreement that a
large troughing pattern will materialize mid week next week. The
models are slightly slower and further south than yesterday, but
still in agreement with a system digging southward over the region.
Trends with this system will need to be monitored closely, as the
ultimate evolution of the system will mean different outcomes for
the area. Trends with a more northerly track, slower system, and/or
more closed system would favor greater precipitation chances. Trends
that would be less favorable for precipitation chances would be a
more southerly track, faster system, and more open system. With all
that said though, the main point at this time is that this type of
pattern will bring increased precipitation chances to the forecast
area, especially for the mountains. Temperatures will also be
expected to drop across the region, to near and possibly below
average values.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 325 PM MST Thu Feb 10 2022
VFR at all taf sites the next 24 hrs. Low risk of some stratus/fog
early Fri morning at KALS, though will only include a sct001 group
for now, as increasing high cloudiness, t/td spreads around 3-5f
and weak west wind toward 12z argue against widespread low
cloudiness/reduced visibility. Cold front moves through KCOS and
KPUB Friday morning, with north wind gusting 20-25 kts at both sites
after 12z-14z. VFR cigs will lower at KCOS after 18z Fri, with a low
risk of a vcsh after 22z. Better chance for snow and a brief period
of IFR cigs/vis at KCOS will likely come after 00z.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HODANISH
SHORT TERM...PETERSEN
LONG TERM...SIMCOE
AVIATION...PETERSEN