Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/24/23
Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
901 PM CDT Thu Mar 23 2023
.UPDATE...
Issued at 853 PM CDT Thu Mar 23 2023
Starting to see our first signs of fog developing across McPherson
county. Latest look at available visibility guidance still
suggests an increase in areal coverage of fog throughout the
night, so not much change to the forecast there. Still dealing
with some stratus over central SD, and expect an increase in that
through the night as well. No changes to low temp forecast as it
remains a tricky and low confidence forecast once again, as it
will largely depend on cloud cover.
&&
.SHORT TERM...(This Evening through Friday Night)
Issued at 206 PM CDT Thu Mar 23 2023
Sfc high pressure will dominate through Friday night. This will set
the region up for dry conditions. However, with afternoon sunshine,
llm will be abundant overnight especially after highs jump into the
30s on Friday. Places with melting snow will see fog develop both
tonight and Friday night. Fog may be dense at times. Temperatures
will be the main forecast challenge given the relatively fresh snow,
fog/stratus potential and weak waa tonight then weak caa Friday
night. Cloud cover is the biggest question mark. Any breaks in the
clouds or drops in the wind will lead to very quick drops in
temperatures both night. Went with a blend of the HRRR and NBM 25th
to try to capture the potential for overnight lows in the single
digits. All temperatures - lows and highs - will remain below normal
by 10 to 25 degrees except from Pierre south where highs will be
close to normal for late March.
.LONG TERM...(Saturday through Thursday)
Issued at 206 PM CDT Thu Mar 23 2023
Not much overall going on in the extended. For the most part, a
strong southern stream split flow should keep us dry with only weak,
subtle features passing through with little continuity between
different deterministic families. The one caveat is at the tail end
of next week when deterministic models begin to develop a deep
trough over the Rockies and eject a Colorado or Texas low type
system. Again, zero confidence at these timescales. The only real
concerns will be the possibility for some light blowing/drifting
snow Saturday. North winds topping out around 20kts at 1/2km and in
BUFKIT mixed down tool...so nothing earth shattering, however we
have a lot of snow sitting around and it remains cold. Speaking of
which, highs/lows through the 7 day period range from 10 to 25
degrees below climo...so don`t anticipate the snow to go away
anytime fast.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday Evening)
Issued at 629 PM CDT Thu Mar 23 2023
Terminals KABR,KATY,KPIR,KMBG
MVFR/IFR CIGs/VSBY are once again in the forecast for the TAF
period. Only KPIR seeing CIGs around 3000 ft at the start of the
period, but models continue to suggest an expansion/development of
the lower CIGs as the night progresses, as well as an onset of
BR/FG.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&
$$
UPDATE...TMT
SHORT TERM...Wise
LONG TERM...Connelly
AVIATION...TMT
Area Forecast Discussion
National Weather Service Burlington VT
1011 PM EDT Thu Mar 23 2023
.SYNOPSIS...
Cool and dry weather is expected on Friday as high pressure briefly
crosses the region. Then as a strong low pressure system passes to
our northwest, an elevationally dependent mixed precipitation and
snowfall event will unfold over the region Saturday into Saturday
night. Some light snow and ice accumulations are possible. After
lingering showers on Sunday, we turn towards drier weather early
next week.
&&
.NEAR TERM /THROUGH FRIDAY NIGHT/...
As of 1008 PM EDT Thursday...Precipitation has all but come to
an end as of 10 PM with just a few spits of rain across central
Vermont. Any lingering shower activity will dwindle quickly over
the next few hours with dry conditions expected by midnight. The
cold front continues to take it`s sweet time as it`s still
hugging the International Border near the St. Lawrence River.
The latest NAM3 and RAP model suites show the front becomes more
progressive over the next few hours which should bring a steady
drop in temperatures and dewpoints as winds shift to the
northwest. Ahead of this front, however, patchy dense fog
continues to plague portions of Vermont given the latest
rainfall, warm temperatures, and extensive snow pack. All signs
show this fog lifted behind the frontal passage.
Previous Discussion...Low pressure currently positioned just to
our north will continue to pull away to the east overnight and
Friday, with ridging following along behind. Widespread rain
this afternoon will taper to showers this evening and come to
an end early Friday as drier air spills in behind the low.
Temperatures will cool overnight as well, so rain may mix with
and/or change over to snow before finally ending, especially in
the higher terrain. Clouds will be slower to depart, and expect
we`ll have a fairly dreary start to the day Friday. Moisture
will continue to thin through the day though, so we`ll see
improving conditions with everyone getting at least some
sunshine before sunset. The ridge crests directly overhead
Friday night, resulting in light winds and at least some
clearing, though high clouds will begin to increase in western
areas toward daybreak Saturday ahead of our next system.
Temperatures tonight will bottom out in the mid 20s to lower
30s, and then we should warm up into the mid 30s to mid 40s on
Friday, perhaps even a bit warmer for those areas that get
sunshine. Friday night will be chilly under the ridge; lows in
the 15F to 25F are expected.
&&
.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
As of 331 PM EDT Thursday...Still expecting a messy mix of wintry
precipitation, though as has been warned over the past couple of
days, the details continue to evolve. Main change has been for the
warm nose aloft to push further north, meaning more mix, and
potentially freezing rain, especially for southern sections/higher
elevations.
Overall the expected set up remains the same, with an anomalously
strong low to lift up to our west. Precipitation will spread
northward into the area Saturday, but with dry air in place, it will
take a while before the column is able to saturate and precipitation
reaches the ground. Models continue to indicate a band of strong
frontogenetical forcing to lift northward late Saturday afternoon
into the evening hours, and this heavier precipitation will aid to
cool the column. Therefore, expect even in areas that warm above
freezing, any light rain will mix with/transition to snow,
particularly at higher elevations. With an 55+ kt 850mb southeast
jet, this first batch of precipitation will focus on the east-facing
upslope sides of the southern Greens and Adirondacks. These winds
will gradually turn to the southwest during the evening/overnight,
ushering in a warmer layer of air aloft. Valley locations may be
able to remain mostly rain as temperatures recover after initial
burst of heavier precipitation. But higher elevations should turn
over to more of a snow/sleet/freezing rain mix, especially
along/south of a Massena, NY to Montpelier, VT line. As a secondary
low starts to develop off the New England coast Saturday night,
temperatures will cool aloft, once again transitioning over to
mainly elevation-dependent rain/snow from west to east. At this
time, latest forecast calls for elevations below 1500 ft see less
than an inch of snow accumulation, with 1 to 4 inches possible above
1500 ft. Ice accumulations would be a glaze to around a tenth, with
the best chances for appreciable accretion in the central/southern
Greens and Adirondacks. However, we continue to stress that given
the complex scenario of elevation vs thermal profiles, these numbers
will likely change as the forecast evolves.
Also of concern for Saturday afternoon/evening will be the potential
for these higher winds to mix down; note the NAM in particular is
quite gusty, with 40-45kt mean-mixed layer winds. The western
downslope sides of the Greens/Adirondacks would be most susceptible
to gustier conditions Saturday afternoon/evening. However, as winds
turn to the west/southwest Saturday night, the St Lawrence Valley
and eastern sides of the higher terrain would see the higher gust
potential.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
As of 331 PM EDT Thursday...Some showers linger around on Sunday as
the double-barrel low system continues trek eastward. There is
potential for strong surface winds given strong low level
westerly/southwesterly flow. Precipitation will taper off by Sunday
evening as ridging starts to build in, giving us some quiet weather
for the start of the work week.
There is a lot of model disagreement regarding midweek and how it
plays out, but there is weakening support for a midweek system like
previous guidance was showing. At this point, continuing the trend
of SChc/Chc PoPs seems to make the most sense given the wide range
of possibilities and large amount of uncertainty. Still plenty of
time for model consensus to increase, but stay tuned to see how
everything will play out.
Temperatures look to remain fairly seasonable through the extended
forecast, with daytime highs in the mid 30s to mid 40s and overnight
lows mainly in the 20s.
&&
.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
Through 00z Saturday...Extremely up and down TAFs this evening.
With rain becoming more showery or scattered, the main vis
concern will be fog for the next few hours. Fog has already
developed in various spots across the forecast area, but the
question remains whether they will impact the airports and for
how long. It will likely be a very unpredictable few hours as
fog moves in and out of sites. Vis expected to drop to 1/4SM at
lowest in KMPV. Cigs will gradually lift throughout the period,
but this will be another timing issue with plenty of tempo
groups, as cigs will go up and down before going solidly VFR.
Lowest cigs will be around 300 ft AGL in KMSS, but like the
other sites, cigs will likely come up to VFR within the next 24
hours. By around 10z Friday, fog will probably not be a concern
anymore, either. Winds calm or southwesterly are expected to
turn westerly (KMSS) or northwesterly over the next 24 hours at
all sites.
Outlook...
Friday Night: VFR. NO SIG WX.
Saturday: Mainly VFR, with areas MVFR and IFR possible. Definite
RA, Definite SN.
Saturday Night: Mainly MVFR and IFR, with local VFR possible.
Windy with gusts to 30 kt. Definite RA, Definite SN, Definite PL,
Chance SHRA.
Sunday: Mainly VFR, with areas MVFR possible. Chance SHRA, Chance
SHSN.
Sunday Night: Mainly VFR, with areas MVFR possible. Slight chance
SHSN.
Monday: NO SIG WX.
Monday Night: Slight chance SHSN.
Tuesday: Chance SHSN, Chance SHRA.
&&
.HYDROLOGY...
As of 330 PM EDT Thursday...A low chance of river flooding will
be monitored for the late tonight into Friday morning period in
response to light to moderate rainfall with basin averages of
0.2" to 0.5" and snow melt up to 1". High dew points have helped
to ripen the snow pack with continued melting at lower elevations.
Therefore, modest to sharp river rises may occur by this evening
into Friday in the watersheds with runoff primarily due to snow
melt.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.
&&
$$
SYNOPSIS...Hastings
NEAR TERM...Clay/Hastings
SHORT TERM...Hastings
LONG TERM...Kremer
AVIATION...Storm
HYDROLOGY...WFO BTV
Area Forecast Discussion
National Weather Service Huntsville AL
1052 PM CDT Thu Mar 23 2023
...New AVIATION...
.NEAR TERM...
(Rest of tonight)
Issued at 918 PM CDT Thu Mar 23 2023
After a very nice day despite some cloud cover with highs
reaching the 80 to 83 degree range in many areas in northern
Alabama, temperatures have dropped into the upper 60s to lower 70s
in most locations at this time. The cloud cover has not dissipated
much north of the Tennessee River yet. Most guidance isn`t picking
up on this, but the HRRR does seem to be. In fact, it hints at
additional cloud cover developing between 10 PM and midnight
tonight further southwest over northeastern Mississippi and NW
Alabama.
Looking at satellite imagery, there appear to be hints that this
will occur over the next few hours. Then HRRR forecasts a lower
cloud deck moving northeast into NW Alabama after midnight. This
looks to be the more widespread and persistent level of cloud
cover overnight. Around daybreak HRRR shows this cloud deck moving
east into NE Alabama and southern middle Tennessee. It looks like
we could see some clearing east of the I-65 corridor possibly
hanging on until just before daybreak, especially south of the
Tennessee River. Thus, expect lows to drop lower in those areas.
Expect a few isolated valley locations such as Fort Payne will be
sheltered from winds as they pick up after midnight for a longer
period, so some lows around 57 degrees could occur in extreme
northeastern portions of Alabama. Further west, based on expected
cloud cover trends and expected winds have raised low
temperatures into the 60 to 65 degree range.
&&
.SHORT TERM...
(Friday through Saturday night)
Issued at 253 PM CDT Thu Mar 23 2023
A low pressure system in western Texas is expected to continue
eastward overnight. In response to this, a cold front will form
and move into the MS Valley Friday night. Ahead and along the cold
front, strong to severe storms are possible. Threats include
tornadoes, damaging winds (both non-thunderstorm/gradient and
thunderstorm), hail, and flooding. As of now, we have medium
confidence in tornadoes and damaging winds-- particularly in NW
AL where our shear and instability align. We also have medium
confidence in the potential for flooding in NW AL, which is
highlighted by a slight ERO from WPC. Model sounding PWAT values
are ranging from 1.4-1.7" in this area, which is approaching or
breaking SPC sounding climatology values per OHX and BMX for March
25. In addition to this, mid and low level RH values are high
(over 75%). The main limitation to flooding will be how fast the
storms move through the area and if any training occurs. For now,
rainfall totals are expected to remain between 0.5" to 1.5" (with
higher amounts in NW AL/southern middle TN and lower amounts in NE
AL).
As the storms move eastward, through the I-65 corridor, we have
low confidence in severe potential due to limited instability.
Despite the lack of confidence in a severe threat, we are
confident there will be a wind threat in some capacity throughout
our entire forecast area both ahead of and behind the cold front.
Due to saturated soils and weakened trees, downed trees and
subsequent power outages are possible. A Wind Advisory will likely
need to be evaluated on the forecast package update overnight
tonight to account for gusts up to 45 mph.
By Saturday morning, thunderstorm chances end gradually from west
to east. However, even after the rain ends, gusty winds will
continue to be a threat as a secondary, dry frontal passage is
possible. Expect dry weather Saturday afternoon into Saturday
night with temperatures reaching the mid to upper 70s before
dropping into the upper 40s to lower 50s.
&&
.LONG TERM...
(Sunday through Thursday)
Issued at 253 PM CDT Thu Mar 23 2023
The main focus in the long term period will be a weak upper
disturbance that slides east through the upper Midwest, pushing a
second cold front through the area on Monday. The stalled sfc front
will begin to lift back north on Sunday, but models continue to keep
the best moisture just south of the forecast area. Slight chances for
showers (15-25%) will return Sunday morning and increase to 50-60%
Sunday evening, primarily south of the TN River. Widespread flooding
does not appear likely at the moment, with models trending farther
south with the higher rainfall axis, but will continue to monitor
trends especially after heavy rain on Friday. Highs will range from
the low to mid 70s both Sunday and Monday, before another shortwave
reinforces a dry and slightly cooler airmass on Tuesday. Temps will
be much closer to seasonal norms through the mid-week period, with
highs in the mid 60s and overnight lows in the low to mid 40s.
&&
.AVIATION...
(06Z TAFS)
Issued at 1052 PM CDT Thu Mar 23 2023
VFR conditions are expected for a few more hours after midnight.
Then around 9Z, expected MVFR CIGS to develop and move northeast
affecting the terminals. Expect these MVFR CIGS to remain in place
through 18Z or 19Z at the terminals before lifting to around 5000
feet. Introduced -TSRA after 4Z at KMSL for a line of convection
expected to be moving through the terminal then. KHSV arrival
looks a few hours later, so left it out of this issuance for now.
&&
.HUN WATCHES/WARNINGS/ADVISORIES...
AL...None.
TN...None.
&&
$$
NEAR TERM...KTW
SHORT TERM....HC
LONG TERM....25
AVIATION...KTW
Area Forecast Discussion
National Weather Service Shreveport LA
1103 PM CDT Thu Mar 23 2023
...New UPDATE...
.UPDATE...
Issued at 956 PM CDT Thu Mar 23 2023
Evening satellite highlights a deep layer of low level cloud
coverage working north associated with stronger moisture advection
underway. Sfc obs showcasing dew points in the 70s being present
across southern zones near Lufkin, TX. Aloft, SW flow will help to
overspread upper level cirrus linked with convection located in
N/TX and S/OK. These storms will continue to move east this
evening, ultimately ending up in our NW zones, specifically
McCurtain County just after sunrise. Looking into the guidance
tonight, some concern does exist regarding the potential for
rotating sfc based thunderstorms in the aforementioned region just
before 7AM. Hi-res guidance suggests sfc based CAPE
1400-1500J/kg, with shear between 30-35kts. Even if rotation does
not materialize, hail and damaging winds will be a threat with
these storms.
Troughing across the SW CONUS will continue to work east
overnight, helping to develop the sfc low that will drift a cold
front across the Four State Region tomorrow afternoon, igniting a
severe weather threat locally where all hazards are in play. This
includes but not limited to damaging winds, hail, and tornadoes.
Some of those tornadoes may be on the stronger side. Decided to
go ahead and add in the severe verbiage to the grids, to then
reflect in the zones forecast for all. Overnight crew will digest
the latest hi-res, present obs and will have an updated forecast
later on in the AM. Temperatures continue to remain on the warmer
side overnight. Noticed the advertised forecast was trending
cooler than what obs presented. This has been adjusted within this
update package.
/53/
&&
.SHORT TERM...
(This evening through Friday Night)
Issued at 253 PM CDT Thu Mar 23 2023
Very nice spring day in progress with low to mid 80s and
southerly winds gusting into the teens and twenties. There are a
few peaks better than 25KT, but not too many. We will be partly
cloudy into the evening with the HRRR edging some thunderstorms
into our NW corner in SE OK after midnight. Not much change
overnight as this activity initially parallels the flow aloft with
very slow movement southeastward until daybreak. This is in good
agreement with the transistion from the SPC day one into day two
with our "severe" wording. Also, to be concurrent with WPC day
two ERO, for our I-30 corridor with "some maybe heavy" with an
inch or two likely in our far north. The model consensus continues
to ever so slowly back off on the pace of a solid push with some
agreement in what looks like a very stormy spring afternoon right
in the heart of our four state area. It looks like some of this
severe potential will linger into the early evening for S AR and
our eastern LA Parishes with warmer lower to mid 80s found here.
Most of us will range in the 70s for highs on Friday. Overall,
most of our area will range from a half to inch for this event.
And unlike previous systems, not much high pressure arriving, but
enough to improve conditions greatly for our early on Saturday.
Our lows by daybreak will range from mid to upper 40s in our NW to
a wide range of 50s everywhere else. /24/
&&
.LONG TERM...
(Saturday through next Wednesday)
Issued at 253 PM CDT Thu Mar 23 2023
In wake of the severe convection Friday afternoon and evening, the
dryline is expected to mix ESE out of Cntrl/NE LA into Wrn MS, with
deep dry air in its wake yielding continued above normal temps but
much lower RH`s areawide with strong insolation. A cool, seasonal
night will return Saturday night, before the remnants of the dryline
begins to lift back N as a warm front after daybreak Sunday, likely
settling into Upper SE TX into Cntrl LA by afternoon. Overrunning is
expected to increase along and N of the front Sunday morning, which
should result in isolated convection developing over Cntrl LA and
spreading NNE and expanding in coverage through the day, aided by
weak perturbations in the SW flow aloft. Have undercut the NBM pops
during the morning as it is a bit more aggressive, but did maintain
likely pops for portions of Deep E TX into Cntrl LA with the
expected increase in convection.
Weak sfc ridging is progged to shift S into the area Sunday night,
reinforcing a drier near sfc air mass back S with the departure of
any large scale ascent associated with the weak perturbations
departing the area. This bndry should not be deep enough to yield
much of a cooldown Monday, as above normal temps return for the
afternoon. While the ensembles remain mostly dry Monday night, the
deterministic models have trended wetter across much of the region,
as the aforementioned sfc bndry retreats back N and becomes
stationary somewhere over E TX/N LA. Aside from slight chance pops
over portions of Deep E TX into NCntrl LA Monday night, have
maintained a mostly dry forecast for now given the uncertainties in
the ECMWF/GFS/Canadian on the sfc bndry location as well as ascent
needed for convection development. However, stronger sfc ridging is
progged to build S into the region Tuesday yielding cooler, more
seasonal temps, and drier conditions for midweek. This should change
though by Wednesday night and especially Thursday, as a SW flow
aloft becomes more established over the region ahead of the next
deepening trough moving through the Desert SW. Thus, a return to
warmer, more humid conditions is expected by late week, aided by
large scale subsidence beneath a building ridge from the TX Gulf
coast into the Lower MS Valley. /15/
&&
.AVIATION...
(00Z TAFS)
Issued at 720 PM CDT Thu Mar 23 2023
Airspace wide VFR to start the 24/00z TAF period under a mostly
clear sky. Light CU field continues to mix in across various
terminals with upper level cirrus following the elevated flow
working in the extreme NW corner of the airspace. Sat this evening
showcases low level coverage working north across the southern
airspace, mainly impacting KLFK. Transition overnight to MVFR to
low VFR is expected to prevail through the day as CIGs remain
lower. The advertised strong to severe storms with all hazards
possible (wind, hail, tornadoes) looks to threaten area terminals
after 24/20z. During this period, given the enhanced prefrontal
sfc southerlies, have elected to keep winds high across area
terminals in advance of the passing line of convection. Southerly
sfc terminal flow between 15-20kts expected with gust near 30kts,
potentially higher with associated storms.
/53/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 85 69 79 55 / 0 10 90 30
MLU 85 68 84 58 / 0 10 80 70
DEQ 81 66 74 47 / 20 60 100 20
TXK 84 70 77 50 / 10 20 90 20
ELD 83 68 79 52 / 0 10 90 50
TYR 85 69 76 51 / 0 10 90 0
GGG 85 69 77 51 / 0 10 90 10
LFK 86 69 80 54 / 0 0 80 10
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...None.
LA...None.
OK...None.
TX...None.
&&
$$
SHORT TERM...24
LONG TERM....15
AVIATION...53
Area Forecast Discussion
National Weather Service Salt Lake City UT
451 PM MDT Thu Mar 23 2023
.SYNOPSIS...The active weather pattern will continue. Another
round of showers will continue through this evening. A cold front
with January-like temperatures and snow levels to valley floors
will cross the area Friday morning through Friday afternoon. Below
normal temperatures will continue into the weekend.
&&
.SHORT TERM (Through 12Z Saturday)...The short term continues to
remain active, with multiple new warnings and advisories issued
with this package. Current radar imagery indicates widespread
showers continue, with some locations seeing brief slushy
accumulations even with the "warm" March sun.
Afternoon satellite and upper air analysis indicates a longwave
trough across the West. A decidedly cold shortwave trough with an
associated jet with an arctic-esque orientation is approaching
the Pacific Northwest Coast. This will be the main player through
the short term forecast and into the long term forecast period and
bring a January-like pattern to Utah.
Expect showers to continue through the early evening, decreasing
in coverage near sunset. As upper level diffluence associated with
the incoming shortwave trough/jet spreads across northern Utah,
expect another round of light snow to develop (though some valleys
below 4500 feet may mix with rain through around 06Z). A portion
of the guidance (~20%) suggests this precipitation may be heavy
times, particularly for Salt Lake County between 2-5 AM. The
remainder of the guidance suggests relatively light, periodic snow
through the early morning period.
A stout cold front will cross northern Utah Friday morning
(roughly 6-10 AM), bringing a period of moderate to heavy snow,
much colder temperatures and gusty winds. Expect northwest winds
to gust to 40 mph for many valley locations for 1-3 hours near and
behind the cold front. This may also cause some blowing and
drifting snow issues for the I-84 corridor from Tremonton to
Snowville.
Snow will continue, heavy at times, through the early afternoon
before again transitioning to snow showers. But this isn`t the end
of the precipitation for the CWA as a series of shortwave troughs
are lined up behind the first to continue to bring the potential
for snow to at least northern Utah through the weekend. It`s
actually a very meteorologically interesting pattern...more fully
fleshed out in the long term discussion.
Given 700mb temperatures near -16C or so and a Great Salt Lake
temperatures around 4C or so (which is well below normal
climatologically), the threat of lake effect snow will increase
Friday night into Saturday morning. Looking at a wide variety of
guidance, much of the guidance envelope indicates more than
sufficient lake-oriented instability, low level moisture and
surface convergence for a well formed area of lake effect snow.
Current expectation is a lake effect snow band is likely (>75%
chance) impacting an area from near Bountiful to the east side of
SLCo. Expect this area may originally develop across the northern
extent of this area and then transition south with time. This band
is universally supported by CAMS, thought location is less
confident.
The going winter weather advisory for the valleys is focused on
the snow totals for the synoptic portion of this system, but
something to keep in mind is that a nearly stationary, long-lived
lake effect band will have areas with significantly more snow.
This is something that is difficult to latch on to location-wise
this far out, so will continue to monitor and adjust the forecast
as needed.
With the Friday morning commute expecting accumulating snow,
especially north of Salt Lake City to the Utah/Idaho border,
issued winter weather advisories for the northern and central
valleys and western Uintas, Book Cliffs, Wasatch Plateau and
central mountains. Given higher expect snow totals in west to
northwest flow, issued a winter storm warning for the Wasatch
Mountain. As typical in this traditional cold front + northwest
flow type event, Utah County from roughly Lehi to near Provo may
see the lower end of the snow totals.
Additionally, with this strong of a cold front, strong
northwesterly flow with sufficient depth for a potential downslope
event exists for Castle Country. Currently, there is moderate
threat (50-60% chance) for wind gusts to 50 mph in/west of the
SR-10 corridor Friday afternoon and evening. Will let the mid
shift evaluate with one more set of model runs regarding a
potential wind advisory, but the threat of high wind warning
threshold being met is low (<10% chance).
The final point is temperatures will struggle to reach even
January levels by Friday. Anyone with outdoor plans through the
weekend should be prepared for a return to winter.
.LONG TERM (After 12Z Saturday)...A broad longwave trough will be
established throughout the western CONUS Saturday. Utah and
southwest Wyoming will have west to northwest synoptic flow with
low levels still saturated after a cold front that is expected to
push through the day before. With Great Salt Lake temperatures
near 3C and 700 mb temperatures near -15C, strong low level lapse
rates and instability will also be in place. HRRR and NAM NEST
model soundings suggest strongly negative omega, or strong lift
through through DGZ. The best lake effect chances are forecast
downwind from a roughly 300 degree synoptic wind, which would
bring the best chances for snow from northern Salt Lake County
into Davis County. Probabilities for high snow accumulations in
the urban corridor are low, but snow rates could be sufficient to
bring accumulating snow on roads.
Temperatures will be some 20-30F cooler than normal throughout
southwest Wyoming and Utah to start the weekend. Lake effect snow
is likely to taper off during the day, as precipitation
transitions more convective throughout southwest Wyoming and
northern Utah. With similar conditions through Sunday morning,
another push of lake effect snow could occur. The main difference
is with wind direction, which will have transitioned more
westerly, so snow chances would be best for Davis County.
Deterministic models and their ensembles are in good agreement on
a ridge building in from the west Monday and Tuesday. That will
bring dry conditions each day with temperatures warming,
especially Tuesday. The stronger warm air advection by Tuesday
will be once the ridge axis tracks through and a digging trough to
the west will bring enhanced southwest flow. Ensemble guidance
has almost 50% of variance on how fast the trough will push
inland. There is high confidence, with all ensemble members
bringing enhanced winds Tuesday or Wednesday and precipitation
Wednesday and Thursday. The most likely scenario is with enhanced
southwest winds Tuesday and precipitation Wednesday through
Thursday.
&&
.AVIATION...KSLC...Scattered rain showers will be possible
through the evening. There is also a 15% chance of seeing
lightning with these showers. Snow is expected to begin around 11Z
Friday and last through the morning. MVFR conditions and mountain
obscuration are likely throughout most of the TAF period. There
is also a 30% chance of seeing IFR conditions due to heavier snow
rates. Southerly winds will transition to gusty northwest winds
around 16Z when the cold front arrives. Winds could become
variable when showers are in the vicinity. CIGS will stay around
6kft after the snow is done.
.REST OF UTAH AND SOUTHWEST WYOMING...Light southerly winds will
transition to gusty northwest winds Friday morning when a cold
front arrives. Scattered rain and snow showers will be possible
through the evening before becoming more isolated overnight. There
is also a 15% chance of lightning with these showers during the
day today. The main band of snow will form Friday morning along
and ahead of the cold front. This band will propagate eastward
through the morning and early afternoon hours in northern and
central Utah. MVFR conditions are likely to occur while it is
snowing and there is a 30% chance that IFR conditions will be
possible when heavier snow rates occur. Even after the snow is
done, CIGS will primarily stay around 6kft for most locations.
&&
.SLC WATCHES/WARNINGS/ADVISORIES...
UT...Winter Weather Advisory from midnight tonight to noon MDT
Saturday for UTZ102>107.
Winter Storm Warning from midnight tonight to noon MDT Saturday
for UTZ108-110-111.
Winter Weather Advisory from midnight tonight to 6 AM MDT
Saturday for UTZ112.
Winter Weather Advisory from midnight tonight to 9 PM MDT Friday
for UTZ113-117.
Winter Weather Advisory from 6 AM to 6 PM MDT Friday for UTZ116-
118.
WY...None.
&&
$$
Kruse/Wilson/Cecava
For more information from NOAA`s National Weather Service visit...
http://weather.gov/saltlakecity
Area Forecast Discussion
National Weather Service Tallahassee FL
947 PM EDT Thu Mar 23 2023
...New UPDATE...
.UPDATE...
Issued at 944 PM EDT Thu Mar 23 2023
Overall, forecast is on track with the likelihood of fog very
high overnight across the region. There`s been some difference in
the guidance tonight favoring dense fog more along the coastal
areas from Panama City eastward into Apalachee Bay and then
extending northward into Southwestern Georgia. At this time,
confidence is sufficient to issue a dense fog advisory for the
central portion of the forecast area based on the last several
HRRR runs plus the local ECAM guidance. It`s entirely possible
spatial expansion of the DF.Y will be necessary overnight.
No other changes were made the current forecast.
&&
.NEAR TERM...
(Through Friday)
Issued at 232 PM EDT Thu Mar 23 2023
The main issue will be development of dense fog overnight tonight,
lingering in places until a couple hours after sunrise on Friday
morning. Dewpoints have risen into the 60s areawide today, except
east of I-75. Underneath dry air aloft, the boundary layer will
readily cool off this evening and become saturated. Timing, coverage
and density of fog will be similar to last night, making a
persistence forecast a good way to go. Will let the evening shift
make a final determination on issuing a Dense Fog Advisory, but an
advisory seems likely. Lowest confidence for fog will be east of I-
75 and along the Suwannee Valley, while highest confidence will be
along and west of a line from Albany to Monticello.
Southerly winds will trend stronger on Friday once the nighttime
inversion breaks. A warm and somewhat muggy air mass will
continue.
&&
.SHORT TERM...
(Friday night through Saturday night)
Issued at 232 PM EDT Thu Mar 23 2023
An upper level trough is expected to swing through the Tennessee
river valley and into the Mid-Atlantic region through Saturday
morning. The upper level ridge overhead will predominantly remain
in place across much of Florida, which will prevent much of the
forcing for ascent to penetrate deep into our region. With the
surface front entering our region on Saturday, there will be some
instability present with SBCAPE values in the 1500-2000 J/Kg range
during the afternoon hours. 0-6km Bulk shear values of 40-50
knots coupled with the aforementioned instability will provide
enough of a favorable environment ahead of the front to produce a
severe threat. Given these parameters, SPC has maintained a
marginal risk of severe weather in our area for Saturday. Overall,
temperatures look to remain warm, with highs in the low 80s, and
lows in the low to mid 60s.
&&
.LONG TERM...
(Sunday through Wednesday)
Issued at 232 PM EDT Thu Mar 23 2023
Beyond Saturday`s front, the upper level ridge pushes back into
the region. This essentially prevents Saturday`s front from
pushing through the region, creating a weak quasi-stationary
boundary that is expected to remain across the region through the
early portion of the work week. Several mid level disturbances are
expected to ride along the northern periphery of the
aforementioned upper level ridge. These disturbances coupled with
the quasi-stationary surface boundary could provide enough forcing
for convection to redevelop along the boundary. The best chances
currently look to remain across the northern portion of the
forecast area in SE Alabama and SW Georgia. At this time,
convection that does develop along this boundary could potentially
be strong to severe; however, there are currently no SPC severe
risks at this time.
&&
.AVIATION...
(00Z TAFS)
Issued at 732 PM EDT Thu Mar 23 2023
Mostly clear skies to start the period but low stratus and fog
will be moving in around 04Z tonight for TLH and ECP terminals,
then quickly spreading further inland, affecting DHN and ABY, then
VLD. LIFR vsbys are likely with 1/2SM and 1/4SM affecting all
terminals. The fog should begin to start lifting around 14z-16z
Friday morning. All sites are expected to be VFR by 17 or 18z
tomorrow.
&&
.MARINE...
Issued at 232 PM EDT Thu Mar 23 2023
Surface high pressure centered over Bermuda will lead to
predominantly southerly flow across all marine zones through
Monday ahead of an eventual frontal passage on Tuesday. This front
will actually reach the region Saturday; however, it is not
expected to clear the region until Tuesday night. This will lead
to several days of shower and thunderstorm activity across the
marine zones starting Saturday afternoon. Ahead of this front on
Saturday, southerly winds will gradually increase to cautionary
levels of around 10-15 knots leading to swells of 2-4 feet across
the marine zones primarily west of the mouth of the Apalachicola
river. Marine zones east of the Apalachicola river are forecast to
maintain swells of 2-3 feet through early next week.
&&
.FIRE WEATHER...
Issued at 232 PM EDT Thu Mar 23 2023
Southerly winds will increase on Friday. Winds will remain gusty
while clocking around southwesterly on Saturday, as a cold front
hangs up across central Alabama and Georgia. Increased winds will
contribute to high dispersion values, particularly over inland
areas. Meanwhile, proximity of the front to our north from Saturday
through Monday will bring scattered showers and thunderstorms, some
of which could be strong. Otherwise, above normal temperatures will
prevail, but the air mass will be somewhat muggy.
&&
.HYDROLOGY...
Issued at 232 PM EDT Thu Mar 23 2023
With widespread rainfall totals of less than 0.25 inches expected
on Saturday followed by scattered to isolated chances of rainfall
forecast through the first half of the work week, there are
currently no concerns for flooding at this time. Saturday`s cold
front could bring some localized pockets of heavy rain from
thunderstorms, but a lack of upper level forcing combined with
dry air aloft will lead to reduced amounts of precipitation.
&&
.SPOTTER INFORMATION STATEMENT...
Spotter activation is not requested. However, spotters are always
encouraged to safely report significant weather conditions when they
occur (while following all local, state, and CDC guidelines) by
calling the office or tweeting us @NWSTallahassee.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 58 84 65 81 / 0 0 0 60
Panama City 63 76 67 77 / 10 10 10 60
Dothan 60 82 65 83 / 0 0 20 60
Albany 57 86 64 83 / 0 0 10 60
Valdosta 58 86 62 82 / 0 0 0 50
Cross City 57 83 61 81 / 0 0 0 30
Apalachicola 63 74 66 76 / 0 10 0 50
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...Dense Fog Advisory from 1 AM EDT /midnight CDT/ to 11 AM EDT /10
AM CDT/ Friday for FLZ010>018-026-027-112-114-115-118-127.
High Rip Current Risk from Friday afternoon through late Sunday
night for FLZ108-112-114-115.
GA...Dense Fog Advisory from 1 AM to 11 AM EDT Friday for GAZ142>146-
155>158.
AL...Dense Fog Advisory from midnight tonight to 10 AM CDT Friday for
ALZ069.
GM...Dense Fog Advisory until 11 AM EDT /10 AM CDT/ Friday for GMZ730-
750-752-755.
&&
$$
NEAR TERM...Godsey
SHORT TERM...Bunker
LONG TERM....Bunker
AVIATION...Montgomery
MARINE...Bunker
FIRE WEATHER...Haner
HYDROLOGY...Bunker