Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/11/24
Area Forecast Discussion
National Weather Service Birmingham AL
923 PM CST Sat Feb 10 2024
...New SHORT TERM...
.SHORT TERM...
(Tonight through Sunday)
Issued at 850 PM CST SAT FEB 10 2024
Showers this evening has been mainly limited to the far northwest
counties. A surface based rain cooled boundary across northwest
Alabama has been shifting slowly southeast, with most of the rain
on the north side of the frontal boundary. This boundary is
forecast to continue a slow southeast slide overnight and reach
the I-20 corridor by 6 AM. Scattered showers will continue
overnight in the warm sector south of I-20. Lightning has been
non-existent across Alabama or Mississippi this evening, but there
have been vertical growth in some cells for the possibility of a
few strikes, and will continue to mention a slight chance of
thunderstorms. The upper level forcing along the boundary will
weaken Sunday morning, and models show shower activity decreasing
significantly in areal coverage. There will likely be a break in
the rain late morning through the early afternoon.
Models show discrete convection developing in the afternoon within
the warm sector south of the frontal boundary. There will be
sufficient instability for deep convection, and forecast hodographs
show 50-60 knots of deep layer shear, which results in 0-3km EHI
values as high as 2. These parameters would certainly support a
low end threat for tornadoes. The severe weather timing threat has
been updated to include afternoon convection.
58/rose
Previous short-term discussion:
(This evening through Sunday)
Issued at 101 PM CST SAT FEB 10 2024
A highly amplified pattern resides over much of the nation with
deep broad troughing over the Intermountain West while very broad
mid-level ridging is centered over the Northwest Caribbean Sea.
Our forecast area is in between of these two dominant features
with a persistent southwest flow aloft. Toward the surface, a
sprawling cold front extends from Eastern Canada southwest through
the Ohio River Valley into the Mid South and westward across
North Texas. Elongated surface high pressure is centered off the
Southeast Atlantic coast but continues to influence the lower-
levels across much of Florida and areas just to the southeast of
our forecast area.
This afternoon.
A broad jet remains over the northern third of the state,
extending across much of the Tennessee Valley Region. RAP 13 km
analysis fields indicate the presence of some 100 to 120 kt jet
maxes from over Northern Louisiana to over Northwest Mississippi
and into Eastern Tennessee. These features are supporting
widespread rain from the Mid South into Northwest Alabama and
further northeast into East/Central Tennessee. Additionally, a few
shortwaves are depicted over Northwest Louisiana, Northwest
Alabama and East Tennessee and these features are providing
further support for this activity. The 10/12z BMX sounding
contains a fairly moist vertical profile up to 700 mb where a dry
slug remains up to about 600 mb. 700 mb mesoscale modeling
indicates a sufficiently moist profile across areas generally
along and northwest of the I-59 corridor while some residual dry
air remains present to the south with one exception being where an
axis of shower activity is advecting northward across portions of
our south-central Counties.
Expect cloudy skies over much of the area with thinner clouds
over the far southeast. The best chances for rain will be across
the far north and northwest counties today while more isolated to
scattered activity will be found near and north of the Interstate
20 corridor with few to isolated chances for showers further south
with exception to that band of shower activity that will continue
to affect portions of our far south-central and southeast
counties through late afternoon. Winds will be from the south at
6-12 mph. Highs will range from the mid 60s east to the low to mid
70s far south and southwest.
Tonight.
The longwave trough makes progress eastward, extending from over
the Northern Plains southwest to over the Four Corners States
overnight while the surface cold front advances southeast,
becoming positioned roughly along the Interstate 59 corridor by
early evening. Several mid-level shortwaves will move northeast
from over portions of Louisiana and Mississippi to over North
Alabama and East-Central Tennessee.
Low-level convergence in vicinity of the approaching surface
front will support further saturation aloft in the low to mid
levels and result in rain chances increasing into the numerous to
likely category generally along and northwest of the Interstate 59
corridor overnight. This area will also have some thunderstorm
potential this evening and overnight with best chances northwest
due to steepening lapse rates with time. Isolated showers are
expected between Interstate 85 and Interstate 59 while only few to
isolated showers are expected southeast of the Interstate 85
corridor. Winds will be from the south at 4-8 mph while lows will
range from the mid 50s far north to the low 60s far south.
Sunday.
A progressive shortwave in the mid levels will push east over
Minnesota and Wisconsin while an upper low becomes more defined
over West-Central Texas. While strong and expansive surface high
pressure builds over the Northwest into the Northern Plains and
southeast across the Midwest, strong residual high pressure
remains to our southeast, resulting in the surface front stalling
roughly along the Interstate 59 corridor through the day Sunday.
The persistent southwest flow aloft with a broad jet aloft and
more shortwave impulses moving northeast over the northern half of
the state will support broad uplift for more showers and some
thunderstorm activity. Lower-level surface convergence in
proximity to the surface front will further enhance vertical
motion and foster continued saturation of the vertical profile,
resulting in high chances for rain and some thunderstorm activity.
Expect widespread scattered to numerous showers and some
thunderstorms Sunday. The persistent southerly flow will help to
pull higher dew points northward with time along with supplying
warmer air from the south into our southwest counties by the
afternoon and evening hours. There will be a risk for some strong
to severe storms across this portion of our forecast area with the
risk existing near and south of the stalled front. Sufficient
low- level instability that materializes will support a risk for
damaging winds and perhaps a tornado, though confidence remains
low given a disparity among the currently available guidance at
this writing. Heavy rainfall across our northern and central
counties will remain the primary concern for this time period with
the risk of localized flooding in urbanized and poor drainage
areas. Winds will be from the south to southwest at 6-12 mph while
highs will range from the mid 60s north to the mid 70s southwest.
05
&&
.LONG TERM...
(Sunday night through next Friday)
Issued at 233 PM CST SAT FEB 10 2024
Looking at Sunday night through Monday, there is spread in model
guidance, now that the time period is within the higher res/CAMs
time frame. There should be a lull in activity at some point,
between one shortwave lifting to the northeast and the main trough
arriving from the west. Guidance is split on if that happens
Sunday afternoon/evening or overnight Sunday/early Monday. Will
carry higher rain chances for now through the night, and maintain
the slight risk for severe storms across the south through Monday
morning. There is still concern about quality of the airmass,
given what is expected to be widespread rainfall tomorrow, and
weak lapse rates. However, expected shear and instability
parameters remain supportive of a few strong to severe storms. The
cold front moves through during the day on Monday, with
rain/storm chances ending. As the upper low swings across the
area, low rain chances will be possible through the evening across
the north.
14
High pressure builds in Tuesday and persists through Thursday,
which will keep the area rain-free. Our next system starts to move
in on Friday with increased rain chances Friday night into
Saturday morning.
25/Owen
&&
.AVIATION...
(00Z TAFS)
Issued at 532 PM CST SAT FEB 10 2024
Widespread MVFR cigs across central Alabama to begin the period
will become IFR by 06Z. Patchy light rain can be expected thru
06Z, with vsbys above 6 miles. A more concentrated area of showers
over nw Alabama will sink slowly southward overnight and reach the
I-20 corridor around 10Z. Vsbys within this band of showers will
be in the 3-5 mile range, with lcl vsbys blo 3 miles. IFR cigs
will remain across north Alabama thru the end of the period, but
improve to 1500-2500 ft agl at KMGM/KTOI after 18Z.
58/rose
&&
.FIRE WEATHER...
Widespread soaking rains and a few thunderstorms possible
through Monday. Afternoon minimum RH values remain above 50
percent through Monday. Southerly 20ft winds will be at or less
than 10mph through Sunday, with winds becoming southwesterly
Monday and increasing to 10-15mph.
High pressure will bring dry weather back on Tuesday through the
end of the forecast period. No RH or wind fire weather concerns
are expected.
&&
.PRELIMINARY POINT TEMPS/POPS...
Gadsden 55 67 57 67 / 90 90 100 90
Anniston 57 69 60 68 / 70 90 100 90
Birmingham 58 69 60 67 / 90 90 100 80
Tuscaloosa 60 71 59 67 / 90 90 90 70
Calera 59 71 61 67 / 70 90 100 80
Auburn 58 70 63 68 / 40 70 100 90
Montgomery 61 74 64 70 / 50 70 100 90
Troy 61 73 64 71 / 40 70 90 90
&&
.BMX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...58/rose
LONG TERM....14
AVIATION...58
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
612 PM EST Sat Feb 10 2024
.KEY MESSAGES...
- Dry weather pattern to prevail into early next week.
- A storm system will likely bypass the region to the south
Monday into Monday night.
- Colder temperatures closer to average take hold next week.
&&
.AVIATION...
Recent AMDAR soundings across srn Mi indicate the MVFR stratus is
located under a deep inversion. The moisture depth is also a little
higher than suggested by most model solutions. The RAP seems the
more reasonable model solution in its current handling of the low
clouds. The solution is fairly bullish with these low clouds through
tonight and into the day Sunday. The low level flow does get fairly
divergent, especially across metro Detroit after 06Z. This may allow
some breaks in the clouds to develop. The RAP does indicate this to
a degree with some late night breaks with redevelopment of the low
clouds later in the morning. Given that little overall change in the
inversion depth is expected tonight, a more pessimistic cloud
forecast will be carried into Sun afternoon, essentially prevailing
MVFR. A weaken of the gradient as sfc high pressure nudges in from
the west tonight will allow a steady drop in sfc wind speeds this
evening.
.DTW THRESHOLD PROBABILITIES...
* High in ceilings aob 5000 feet through this evening.
&&
.PREV DISCUSSION...
Issued at 306 PM EST Sat Feb 10 2024
DISCUSSION...
Confluent upper level flow will continue (and intensify) into early
next week as southwesterly subtropical plume around strong southern
stream shortwave south of the four corners region impinges on a more
westerly (but wavy) upper flow becoming established around the base
of upper level troughing in the northern stream throughout eastern
Canada. Surface high pressure ridging will expand eastward into the
area in response to this upper pattern with dry weather persisting
over the next several days. Temperatures will remain notably cooler
than the 50s to lower 60s that graced lower Michigan late this past
week with highs generally ranging in the upper 30s to lower 40s. As
high pressure becomes more prominent, expect more in the way of sun
area-wide as well.
The biggest potential weather maker for this forecast period will be
that large southern stream shortwave now over the southwest CONUS.
At this time, a plethora of model solutions strongly suggest this
system will remain south of the region as is ejects on a shallow
trajectory from the southwest CONUS and southern plains into the
Tennessee and Ohio valley regions Monday into Monday night. Such a
track would keep even the northern periphery of precipitation (snow
in this case) safely south of the Michigan and Ohio state line.
A somewhat complicated configuration of shortwaves from the Gulf of
Alaska east into the Yukon and also south through the far eastern
Pacific ocean to the Pacific Northwest coast cloudy the forecast
track of this system ever so slightly as the eventual northern
stream wave that digs southeast through western Canada into the far
northern Mississippi Valley from this mess will impact the steering
of this southern system as it makes its closest approach to the
region. In fact, eventual phasing of these features is forecast
throughout the model space, just well east of the region from New
England into Newfoundland. At this time, it appears this northern
wave will be subdued enough to allow this storm system to remain on
this more southern track around the base of the eastern Canadian
upper trough as it exerts the main influence on steering currents.
In the extended period from mid-late next week, this cooler upper
level pattern persists as additional northern stream shortwave
energy sweeps into the area and maintains temperatures in the 30s to
around 40. Precipitation chances (mainly snow) increase from this
system by around Thursday, but with some flurry/sprinkle chances
scattered throughout the later half of next week. In the wake of
this larger system, notably colder air begins to seep southeast into
the Great Lakes from late week on into next weekend. With this in
mind, expect highs to settle closer to 30 with time by the end of
this 7 day forecast and just beyond.
MARINE...
High pressure expands into the Great Lakes through the weekend,
maintaining light westerly flow through Monday and dry weather for
the nearshore and adjacent Lake Huron open waters. The northern half
of Lake Huron maintains sporadic coverage of snow showers owing to
slow departure of the Hudson Bay low through the weekend. A strong
low pressure system tracks across the Ohio Valley Monday-Tuesday,
with the broader local impact being a uniform shift to northwest
flow and localized, low (<20%) precipitation chances for western
Lake Erie. A trailing northern stream clipper draws lake enhanced
snow potential into the southern open and nearshore waters Tuesday.
There will be a brief return of high pressure mid-week before low
pressure and its attendant cold front arrive late this week which
will be the best opportunity for headline-worthy marine conditions
during the forecast period.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...None.
Lake Huron...None.
Lake St Clair...None.
Michigan waters of Lake Erie...None.
&&
$$
AVIATION.....SC
DISCUSSION...DG
MARINE.......MV
You can obtain your latest National Weather Service forecasts online
at www.weather.gov/detroit.
Area Forecast Discussion
National Weather Service Green Bay WI
541 PM CST Sat Feb 10 2024
Updated aviation portion for 00Z TAF issuance
.KEY MESSAGES...
- Quiet and seasonably mild weather will continue into the middle
of the upcoming week.
- Chances for light lake effect snow in northern Wisconsin
throughout the week. No major impacts are expected.
&&
.DISCUSSION...
Issued at 241 PM CST Sat Feb 10 2024
Short Term...Tonight and Sunday
The latest RAP analysis and satellite/radar imagery show Wisconsin
positioned between high pressure over the northern Plains and low
pressure over far northern Quebec. Northwest winds continue to
advect in a cooler airmass as well as cloud cover. 12z and amdar
soundings depict a shallow moist layer and therefore expect the
trend of eroding cloud cover to erode from south to north through
the rest of the afternoon. However, there is widespread low clouds
upstream and within the surface high. As the high drifts southeast
towards the western Great Lakes, forecast challenges mainly
revolve around cloud cover and temperatures.
High pressure will slide southeast from the northern Plains to the
mid-Mississippi Valley over the next 24 hours. Thermal profiles
modify slightly, but winds will remain out of the northwest or
west-northwest, with some indications of stratus returning into
north-central Wisconsin around midnight and continuing to spread
southeast. Without low level cold advection, have doubts that this
cloud cover will reach into northeast WI due to downsloping. But
additional cloud cover will also arrive late tonight into Saturday
morning ahead of a digging shortwave trough. Given the track of
the surface high, it`s possible that winds bounce in and out of
being calm. Combined with cloud cover, trended slightly warmer
than the previous forecast for low temps.
Sharp shortwave energy will track across the region on Sunday.
Moisture is severely lacking below 12000 ft, so no chance of any
precip. But will see cloud cover for the morning which should give
way to increasing sunshine in the afternoon. High temperatures
will be similar to today`s readings in the low to mid 30s.
Long Term...Sunday Night Through Saturday
The El Nino pattern of the last couple of weeks is
forecast to break down by the end of this week, as an upper ridge
builds along the West Coast and a Polar low moves south towards
the eastern half of the Lower 48s states. The first round of much
colder air looks to arrive next Sunday night as a 1035mb surface
high moves into the Northern Plains and Front Range. The GFS and
ECMWF suggest that a synoptic scale storm could bring snow to our
region Monday or Tuesday followed by another round of colder air
during the middle part of next week.
Some lake effect snow showers are possible in far northern Wisconsin
this week, but significant snow is unlikely. A front moving through
Thursday could bring some snow or rain showers. Temperatures will
remain around ten degrees above normal through the end of the work
week, with closer to normal temperatures next weekend.
&&
.AVIATION...for 00Z TAF Issuance
Issued at 534 PM CST Sat Feb 10 2024
Started off with the idea that stratus would continue to erode
from south to north this evening, but satellite trends suggest the
opposite. Have now decided to keep low clouds in place (and fill
in over C WI and the southern Fox Valley) through the night and
Sunday morning, with ceilings varying from 2000-2500 ft agl
northwest to 3000-3500 ft agl southeast. Don`t expect any
appreciable clearing to occur until subsidence in the wake of
short-wave trough overspreads the region Sunday afternoon. Light
to moderate W-NW winds will prevail through the TAF period.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
DISCUSSION.....MPC/RDM
AVIATION.......Kieckbusch
Area Forecast Discussion
National Weather Service North Platte NE
544 PM CST Sat Feb 10 2024
.KEY MESSAGES...
- No changes to ongoing Winter Weather Advisory; light to
moderate snow will lead to snow covered roads before exiting
to the south late tonight.
- Added a mention of patchy fog late tonight across the eastern Panhandle,
western Sandhills, and far southwest Nebraska with dense fog
possible.
- Sunday through the middle of next week will favor mostly dry conditions
and moderating temperatures though weak disturbances in the
general northwesterly flow may yield light precipitation
chances favoring the north.
- Much cooler temperatures arrive late week behind a strong cold
front with additional snow potential though confidence in
timing and amounts remains very low at this time.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 328 PM CST Sat Feb 10 2024
A broad area of light to moderate snowfall continues to slowly shift
north and east across the central Sandhills. Radar imagery shows the
highest intensity snowfall across central Cherry County and the 20z
observation from Valentine (KVTN) show sub-1 mile visibility.
Further southwest though, in the wake of this heavier snow, area
road cameras show efficient melting off road surfaces with many
highways showing only partially covered or wet surfaces. This lends
confidence to only brief impacts to any one location. Various hi-res
guidance including the early afternoon runs of the HRRR and RAP
suggest this area of snow will gradually wane through late afternoon
with a secondary enhancement across the southern Panhandle into
southwest Nebraska this evening. This will largely be driven by low-
level convergence in the vicinity of the Cheyenne Ridge with mid-
level steering flow carrying new development further north and east.
With the lack of stronger DCVA, intensity of later snowfall is not
expected to be as high with snowfall rates likely remaining near
0.50" per hour. Winds remain weak, generally at or below 15 mph, so
visibility restrictions due to blowing snow are not anticipated.
Elongated trough axis will shift south and east tonight, clearing
the area prior to dawn Sunday. Behind this feature, a slug of dry
mid-level air will overspread the area and associated subsidence
should help erode the overcast skies in the early morning hours
Sunday. This drier air with clearing skies in a region of light
winds will favor radiational cooling and so have some of the coldest
lows in recent days forecast across our western zones. With the
ongoing snow, snow melt, and colder temperatures incoming, will need
to monitor the potential for fog and patchy dense fog at that.
HREF/HRRR/RAP guidance all highlight areas west of Highway 61 as
seeing the threat for fog with some solutions depicting half mile
visibility or less. Saturday morning HREF guidance shows a fairly
large area of 70%+ probabilities for seeing less than one mile
visibility. Knowing full-well that CAMs can be overly aggressive
with visibility reductions and lingering uncertainties about the
clearing line for clouds, will limit mention to patchy fog for now
and allow later shifts to decide if dense fog messaging should be
ramped up. Regardless of fog development, the falling temperatures
and wet surfaces may lead to refreeze conditions and so caution is
advised to folks traveling in the area. This was considered as well
with respect to maintaining at 12z (5am MST) end time to the Winter
Weather Advisory on Sunday. Overnight lows will range from the low
teens in the west to middle 20s east.
&&
.LONG TERM /SUNDAY THROUGH SATURDAY/...
Issued at 328 PM CST Sat Feb 10 2024
Quieter conditions arrive for the day Sunday and last through much
of the early week. Departing trough will give way to ridging
focusing across the southwest. Low amplitude northwesterly flow will
settle in across the western CONUS, with gradual west-northwesterly
flow and the associated downsloping component should drive
moderating temperatures across the region. Lingering snowpack may
inhibit the temperatures climb for areas west of Highway 83,
however, increasing h85 temperatures to seasonable to slightly above
normal values will allow daytime highs to reach the 40s and 50s
through Tuesday.
Towards the middle of the week, a southeastward diving disturbance
will drop across the Northern Rockies and Northern Plains. Inherited
NBM PoPs were limited to the Pine Ridge and points northwest but
latest EPS/GEFS suggest higher probabilities further east along the
Nebraska/South Dakota border. Because of this, opted to expand
Slight Chance (< 25%) PoPs further east towards the Missouri River
Valley. This lines up with the latest WPC QPF. Precipitation type
would favor snow but given light QPF amounts, only minor snow
appears likely. Following a cold frontal passage, temperatures drop
quickly for the latter half of the week with a return to below
normal values for a brief spell. Ensemble mean temperatures show
highs returning to the upper 20s to lower 30s and persisting through
the following weekend. The same ensemble solutions are focusing on
late Friday through Saturday for increased precipitation chances
across much of the local area. NBM inherited PoPs peak in the 25-35%
range (Chance category) and see no need to alter these. Again,
precipitation type would favor snow with little signal for any ice
though at range these probabilities can change quickly so folks
should monitor later forecasts for up-to-date information.
Confidence in forecast details decreasing thereafter as NBM 25th to
75th temperature spread increases significantly with guidance
varying 10 to 15 degF for Friday and beyond. Latest NAEFS guidance
for the 8 to 14 Day period suggests continued probabilities for
above normal precipitation but lower certainty on temperature
outlook.
&&
.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 536 PM CST Sat Feb 10 2024
Light snow showers will continue through early evening before
tapering, generally across the Sandhills into portions of
southwest and north central Nebraska. Snow showers combined with
lower cigs will drop conditions to MVFR or lower at times this
evening into tonight. Cigs across northern Nebraska will begin
to lift overnight, but linger into the morning hours across
southern portions of the forecast area, including KLBF terminal.
By Sunday afternoon all of western and north central Nebraska is
expected to have VFR conditions. Winds will shift to the west
Sunday afternoon around 5 to 10 kts.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 5 AM MST Sunday for NEZ004-
022>024-035-056-094.
&&
$$
SHORT TERM...NMJ
LONG TERM...NMJ
AVIATION...Gomez
Area Forecast Discussion
National Weather Service Marquette MI
604 PM EST Sat Feb 10 2024
.KEY MESSAGES...
- Temperatures trending back closer to normal through early next week,
but still above normal. With further cooling next week,
temperatures will settle to around normal.
- The trend to colder weather will be supportive of lake effect
snow next week, periodically enhanced by clipper type
shortwaves, but at this point, snowfall is expected to be on
the light side overall.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 255 PM EST Sat Feb 10 2024
Water vapor imagery and RAP analysis show troffing extending from
central Canada to the southern Rockies, though flow in the trof is
split with a strong southern stream shortwave over the southern
Rockies and a northern stream shortwave extending from Manitoba to
eastern MT. The northern wave will be of interest to the fcst here
on Sun. Downstream, westerly flow into the Great Lakes today
featured a shortwave that moved across Upper MI/Lake Superior. Radar
imagery showed a nice circulation to the -shsn that accompanied it
across the area. In the wake of that feature, drier air and
subsidence has resulted in -shsn diminishing under low-level nw
flow. Per latest RAP analysis, 850mb temps are only around -10C,
marginal for LES without synoptic support.
While we await the next shortwave, 850mb temps tonight remain fairly
steady state around -10/-11C, marginal for LES. Inversions are also
low at 3-4kft, and the DGZ is above the inversion. Given the
negatives, LES may end completely or diminish to nothing more than a
few flurries. For now, will retain isold-sct -shsn wording in the
fcst over the eastern counties where longer fetch under nw flow may
continue to support a few -shsn thru the night. To the w, don`t
expect anything more than a few flurries. Toward 12z, forcing from
approaching shortwave and resulting erosion of the low inversion
will lead to some expansion of light LES. Lows tonight will be in
the upper teens to mid 20s F. If some locations see clouds scatter
out for a while, temps will fall to the mid teens F.
&&
.LONG TERM /SUNDAY THROUGH SATURDAY/...
Issued at 435 PM EST Sat Feb 10 2024
Much of the extended period will be impacted by a series of
shortwaves/clippers moving through the region as the pattern trends
toward northwest flow, thus supporting multiple LES chances. The
first of these disturbances is progged to drop southeastward across
Upper Michigan on Sunday, weakening any ridging in the upper levels.
Best forcing with this wave will arrive during the afternoon hours
on Sunday. Next, another shortwave will quickly follow on Monday.
But, just like Sunday`s wave, ensembles trend toward low qpf and
weak forcing. As a result, it will be tough to accumulate any
significant snow amounts. As the pattern continues through Tuesday
though, snow accumulations across west to northwest wind snow belts
could climb into the 1 to 3 inch range with some locally higher
amounts up to 4 inches. Model consistency at this time though
remains poor, so timing and amounts could still fluctuate quickly.
Best chances for heaviest lake effect snow will come late in the
week/early next weekend as colder air overspreads the region. After
high temperatures struggling to hit the freezing mark from Sunday
through Thursday, high temperatures closer to normal will return
Friday and Saturday (generally 20s). And, a slight uptick into the
50 to 70pct range for Pops was one noticeable change from previous
model runs.
&&
.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 604 PM EST Sat Feb 10 2024
VFR conditions look to move over KIWD tonight as some higher cigs
are being realized upstream in northern WI right now. Meanwhile,
MVFR cigs look to continue across KCMX tonight into Sunday morning
as some lake-effect cloud cover continues across the Keweenaw; it`s
possible (30% chance) that we see some light lake-effect flurries
occur from time to time throughout the night. That being said, I
don`t believe the flurries will do much at all in effecting the
terminal conditions. While KSAW appears to stay in the upper-half of
MVFR cigs this evening, they could (50% chance) improve to VFR cigs
late tonight as the higher cigs currently over northern WI
eventually makes its way over the central U.P.; whether they stay in
the low-end VFR conditions is questionable, as most model guidance
keeps MVFR conditions over the terminal until Sunday afternoon. As a
disturbance makes its way into the U.P. Sunday, it`s possible (50%
chance) that we see at the very least some flurries over the NW wind
snow belts Sunday. Thinking the best chances for snowfall will be
over KCMX, where we could dip into IFR vis from time to time do to
the light snowfall.
&&
.MARINE...
Issued at 449 PM EST Sat Feb 10 2024
Northwest winds will fall below 20 knots tonight as the pressure
gradient weakens. And, this is where they are expected to stay
through Wednesday night with just a few wind shifts first to the
north/northeast and eventually all the way around to the southwest
by Wednesday. By Wednesday night, 20-25 knot winds will develop
across the eastern portions of the lake, becoming more widespread
over central portions as well on Thursday. Meanwhile, winds will
veer from the southwest to the northwest from Wednesday night
through Thursday morning.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
Small Craft Advisory until 1 AM EST /midnight CST/ Sunday for
LSZ241>244.
Small Craft Advisory until 10 PM EST this evening for LSZ247-
248.
Small Craft Advisory until 10 AM EST Sunday for LSZ249>251.
Lake Michigan...
None.
&&
$$
SHORT TERM...Rolfson
LONG TERM...TDUD
AVIATION...TAP
MARINE...TDUD
Area Forecast Discussion
National Weather Service Nashville TN
814 PM CST Sat Feb 10 2024
...New UPDATE...
.UPDATE...
Issued at 800 PM CST Sat Feb 10 2024
Surface cold front is still off to our west, moving through
southern MO and southern IL at this time. Ahead of it in our
area, this evening`s sounding shows a very saturated atmosphere
with a PWAT of 1.11 inches - not a record, but still over the 90th
percentile for the day. Rain continues to track across the area
until this cold front sweeps through Middle TN early Sunday
morning. Highest rain totals so far today have favored the south
where 1 to 2 inches has been measured. So far, everything is
behaving in terms of localized flooding with all rivers still well
below action stage. And while rain will continue still through
the next several hours, probability of rain totals exceeding 3
inches is still very low. But while widespread flooding is not
expected, won`t rule out some nuisance flooding in low water
crossings and other sensitive areas.
Once this cold front moves through early Sunday morning, a break
in the rain is then expected. It won`t last long though as the
next (and final) round of rain arrives by late afternoon.
&&
.SHORT TERM...
(This afternoon through Sunday Night)
Issued at 146 PM CST Sat Feb 10 2024
Rain, rain, and more rain is the story for the rest of today. The
thunderstorms that once were on the leading edge of the precip
shield have withered away as the marginally unstable airmass has
become much more saturated. RAP analysis shows there`s still some
instability at the surface and in the mid-levels, around 50-100
J/Kg, but these values will continue to fall. Even with the small
amounts of instability, there`s still a chance for a few rumbles of
thunder. 6-hour QPE values from the rain this morning range from a
few hundreths of an inch across our NW counties to 1 inch over
our southern-most counties. Current radar notes widespread showers
across almost all of Middle Tennessee with a few heavier pockets
across Wayne and Lawrence counties; no lightning as of lately.
In terms of flood potential, a few spots could see some isolated
flooding, mostly across our southern and southeastern counties
where the surface boundary is through tonight. With the threat
being so marginal, no flood headlines will be posted with this
package. Will we end up having to issue a flood advisory tonight?
Maybe. But the overall threat for any significant flash flooding
to occur is very low. 12Z HREF probabilities yield a 43% chance
of exceeding 3 inches of rain in the aforementioned areas by
Monday, which is when the last round of rain will move in.
Nonetheless, we`ll certainly be keeping an eye on our local
streams and typical flood-prone areas just to be safe. Currently,
no rivers in our area are forecast to hit action stage, but we`ll
still be keeping an eye on them, too.
CAMs continue to show a lull in the precip occuring Sunday as this
current batch of rain comes to an end overnight. Rain will re-enter
the area late Sunday night as a cutoff upper-level low approaches
the southeast. More details about this system in the long term
discussion.
Temperatures in the short term will be warm-ish. Today kinda doesn`t
count because it`s rained out, but current temps are hovering right
at 60 degrees. Sunday will be a bit cooler with highs in the low
50s as an approaching cold front stalls out over the area
tonight. Overnight lows will also be on the warmer side with
temps in the upper 40s to low 50s areawide.
&&
.LONG TERM...
(Monday through next Saturday)
Issued at 146 PM CST Sat Feb 10 2024
The approaching cut-off low moving into the southeast Monday will
bring with it an associated surface low. The high-res NAM shows
this surface low moving directly over Middle Tennessee on late
Monday morning. If this turns out the be the case, the chance for
any severe storms will be quite limited as there won`t be enough
instability for the storms to work with. Gusty winds, however, do
look likely Monday as that low spins across the area. The NBM
tosses out a 45% chance of surface-base CAPE exceeding 250 J/Kg
Monday morning across portions of our southern counties and a
small area over the Plateau. Again, whether these values will be
achieved or not will largely depend on the track of the surface
low. The most likely outcome is that there could be a few stronger
storms in those areas Monday morning/afternoon, but the majority
of the forecast area will likely only see showers with gusty
winds.
Temperatures will drop back into the 30s come Monday night and a
rain/snow mix is possible across the Plateau as the surface low
moves NE out of the area. The window of time for the rain/snow will
be small, thus accumulations are not expected. All precip finally
exits the area overnight Monday and we welcome back some sunshine
by Tuesday. A shift in the upper-air pattern to a more zonal-
type flow will help bring high pressure to the area for the
remainder of the work week. Temperatures in the extended period
will once again be warmer than normal for February - highs in the
upper 50s and overnight lows in the 30s. Models are hinting at
another disturbance aloft possibly bringing more rain chances to
the area by next weekend.
&&
.AVIATION...
(00Z TAFS)
Issued at 528 PM CST Sat Feb 10 2024
VERY low confidence TAF forecast with the current system moving
through Middle TN. Places where it`s VFR are IFR and vice versa.
Will run with a general thought of conditions worsening to MVFR
and IFR overnight as rains continue through 08-10Z.
Wind are light, but starting to shift to the north with fropa over
the next few hours.
&&
.PRELIMINARY POINT TEMPS/POPS...
Nashville 49 60 49 59 / 100 50 70 90
Clarksville 45 57 45 53 / 100 40 70 90
Crossville 47 59 47 59 / 100 60 70 90
Columbia 50 60 49 61 / 100 70 80 90
Cookeville 49 59 49 59 / 100 30 70 90
Jamestown 46 57 45 57 / 100 40 70 90
Lawrenceburg 50 60 50 62 / 100 70 80 80
Murfreesboro 50 61 49 62 / 100 60 70 90
Waverly 45 57 45 55 / 100 60 70 90
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE.......Clements
SHORT TERM...Baggett
LONG TERM....Baggett
AVIATION.....Unger