Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/26/24
Area Forecast Discussion
National Weather Service Binghamton NY
1026 PM EST Sun Feb 25 2024
.SYNOPSIS...
A weak disturbance will move through the region tonight with a
few rain and snow showers. After short lived high pressure
Monday a warm front will push through the region Tuesday
afternoon and Wednesday with the next chance of rain showers.
This is followed by a strong cold frontal passage Wednesday
night with another round of rain, changing to snow showers.
It will be cold and blustery with lake effect snow showers on
Thursday, then warming up under high pressure into next weekend.
&&
.NEAR TERM /UNTIL 6 PM MONDAY EVENING/...
1025 PM Update
Very dry low level air remains in place. Radar returns are all
aloft (virga) at this time. Dew point depression are still large
back into Western NY currently; only Erie, PA is reporting light
rain as of 10 PM. The latest HRRR, RAP and 00z 3km NAM continue
to show lower QPF amounts, with it not looking like just
isolated rain/snow showers and sprinkles overnight. QPF, Snow
and the localized ice amounts were lowered (from the already
minimal amounts) with this update. Also, temperatures were
running several degrees warmer than expected, so some
adjustments to the hourly temperature trends were made...but
overnight lows were not changed.
625 PM Update
Very dry low level air is present, with current surface dew
points still in the upper single digits to teens out there. With
temperatures still in the mid-30s to lower 40s, there remains a
large dew point depression. Model guidance still insist that the
front and associated moisture will eventually over come this dry
air in the low level; with some scattered snow and rain showers
breaking out toward or after midnight across CNY. QPF amounts
are very light, only a few hundreths of an inch as most and
perhaps a localized coating to snow over the hilltops. Further
south in NE PA, there will be some sprinkles, isolated freezing
drizzle and snow flurries over the higher elevations late
tonight and early Monday morning. Confidence and amounts were
not high enough (for freezing rain) to be inclined to issue any
advisories or special weather statements at this time. Will have
to wait and see if this light mixed precipitation can actually
overcome the dry layer and have any impacts early Monday
morning. Overnight lows still on track to reach the mid-20s to
low 30s over NE PA, with 25 to 35 degrees expected over CNY.
Previous Discussion Below
While a disturbance will move through the region tonight, dewpoint
depressions are currently fairly large. As a result, it will take
some increase in moisture to generate any precipitation with
radar likely depicting virga at times. The best lift still looks
to be along the Ny Thruway into far eastern portions toward the
Western Catskills where a few hundreths of QPF could get
squeezed out tonight. Temperatures also look marginal, around
freezing on average across the region. A warm nose around 900 mb
is forecasted to surge northeast overnight as well into NE PA
and the Southern Tier of NY. So, if precipitation occurs in
these regions drizzle or freezing drizzle would be the types.
Areas where precipitation has the highest chance to occur look
to have deeper mid-level cold air making that more of rain and
snow shower mix. Any snowfall should be an inch or less.
This disturbance quickly moves east of the region Monday. Some
clearing should occur as a result with temperatures continuing
the warming trend toward 50 for highs. A warm front then looks
to push toward our region with ample southwest flow. With some
clouds around as well lows should only fall into the upper 30`s
on average.
&&
.SHORT TERM /6 PM MONDAY EVENING THROUGH WEDNESDAY NIGHT/...
250 PM Update...
A ridge builds just east of the region leading to strong
southwesterly flow advecting in warmer air. Temperatures will max
out in the upper 50s and low 60s. A couple of weak shortwaves will
ride the ridge and pass through the region bringing a slight chance
for a passing shower or two Tuesday afternoon and evening. Chances
for showers increase late Tuesday night as showers ahead of a strong
cold frontal boundary move in from the west. Models have some MUCAPE
over the region late Tuesday and overnight, though any instability
would be elevated as the surface will be quite stable. Shear will be
around 50 kts. Based on this, isolated non-severe thunderstorms
cannot be ruled out but confidence was too low to include in the
forecast due to the limited coverage. SPC has included us in the day
3 outlook with just general thunder. Winds also increase ahead of
this system with gusts of 25+ mph. Lows on Tuesday will be mild as
temps only drop into the 40s and low 50s.
Scattered showers ahead of the front continue Wednesday as chances
for heavier showers increase. PWATs will increase to near an inch
which is at least 3 standard deviations above normal. The main band
of showers enters the region late Wednesday and passes through
Wednesday night. Despite the potential for heavier showers, hydro
issues are not a concern as this system will be relatively quick
moving and there is little to no snowpack across the region. There
will be strong forcing with this front but showers earlier in the
day will prevent the environment to become unstable enough for
thunderstorms. Winds become stronger with this system as well. With
the potential of gusts of 40 to 50 mph, advisories may be needed.
This update did go slightly lower than guidance with the winds,
especially Wednesday night as the front moves out.
Temperatures will warm up into the 50s and 60s once again on
Wednesday. Cold air will be quick to fill in behind the front, so
temperatures will drop into the 20s and low 30s. Timing of the front
will be a factor into how cold temps get Wednesday night/early
Thursday morning. There continues to be large spread in ensemble
guidance. With temperatures dropping overnight, rain behind the
front mixes with snow and then becomes just snow. Light
accumulations will be possibly by Thursday morning.
&&
.LONG TERM /THURSDAY THROUGH SATURDAY/...
250 PM Update...
Following the front, post-frontal lake effect snow showers develop
across portions of Central NY, leading to additional snow
accumulations. Temperatures will remain below freezing for most of
the region, though some valley locations will just climb into the
30s. High pressure builds into the region and will bring an end to
the lake effect snow Thursday night. Temperatures will fall into the
teens overnight. Beyond Thursday, quiet and warming conditions
are expected through the weekend with highs back in the 50s for
Saturday and Sunday. A system off the coast of the Carolinas
will try to send some showers up our way this weekend but dry
air may be enough to keep them out. This forecast favored drier
solutions.
&&
.AVIATION /04Z MONDAY THROUGH FRIDAY/...
VFR conditions are in place this evening with some high clouds
beginning to stream in from the west ahead of an approaching
disturbance clipping the area. This system can produce spotty
rain and snow showers that may result in brief MVFR ceilings and
visibility for SYR and RME, but confidence is low in this
occurring as looking back to the west, dew point depressions
remain high with little to no precipitation being reported and
ceilings VFR back through the Great Lakes. If precipitation does
develop and impact the northern terminals, the best window
looks to be between 04-07Z and TEMPOs have been added to cover
that.
Ahead of this disturbance, soundings and near term guidance do
support there being low-end LLWS out of the southwest at all
terminals, with confidence being highest for ELM, ITH and SYR
with 35-40 knots of shear possible. The window for LLWS runs
from 00-08Z.
Tomorrow is expected to be VFR with winds in the morning
becoming westerly. Toward the end of the TAF winds are expected
to start to shift more to the north-northeast, but speeds look
pretty light.
Outlook...
Monday night... VFR.
Tuesday through Thursday...Restrictions likely due to rain
ending as snow showers. Breezy, southwest winds shifting to west
or northwest by Thursday. LLWS possible at some point
Tuesday/Wednesday.
Friday... VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...None.
NY...None.
&&
$$
SYNOPSIS...MJM/MWG
NEAR TERM...MJM/MWG
SHORT TERM...BTL
LONG TERM...BTL
AVIATION...DK/MWG
Area Forecast Discussion...Updated
National Weather Service Billings MT
823 PM MST Sun Feb 25 2024
.UPDATE...
Windy evening for places along the foothills and near the
mountains. Winds have been gusting into the 60s mph at Livingston,
with reports of 50 plus mph at times from Roscoe to Dayton to
areas southwest of Big Horn in Sheridan County. Expect winds to
increase further later this evening and overnight as stronger
700mb winds move overhead. Latest hi-res models continue to show
the mountain wave potential for adjacent foothills. Have adjusted
winds through the evening to account for latest trends. The wind
highlites look to be in good shape and will make no changes. Snow
has been working into the southwest mountains as well, with the
Fisher Creek SNOTEL north of Cooke City reporting 0.50 inches of
snow water equivalent today. Light snow will continue overnight
in the mountains as moisture advects in from the west. An updated
aviation discussion is below. STP
&&
.DISCUSSION...
Today through Tuesday...
Damaging winds possible tonight over the mountains and area
foothills, transitioning quickly tomorrow afternoon to a brief but
intense period of Winter weather.
Overall the wind event for tonight into tomorrow morning is on
track. Latest HRRR is showing better potential for mountain wave
winds working down into the Red Lodge and Sheridan WY areas so
added these foothills areas of the Beartooth and Bighorn mountains
as well as the Bighorn mountains themselves to the going High Wind
Warning. Overall the strongest winds tonight should occur between
9pm and 4am, though gusts near 60 mph could continue into the late
morning/early afternoon. In general strong winds are possible
until the cold front arrives tomorrow afternoon. One caveat for
mountain wave wind events is the erratic nature of the strong
gusts. Winds could be calm at times then a 60+ mph gust can
arrive, its not a more continuous strong wind event like we
usually experience. Those sudden strong gusts (going from light
winds to 50+ mph) is what causes tree and property damage, and
this event will be strongest during the night time hours. The
sudden gusts are also cause for concern for travelers tonight,
particularly on portions of I-90 in Sheridan/Big Horn counties
where the road is perpendicular to the wind direction.
Cold front arrives late morning into early Monday afternoon. This
frontal passage will usher in much colder air and get
precipitation going pretty quickly after its passage. The front
will also diminish wind speeds and turn the direction sharply to
the north. Lates Metro model indicates road temperatures across
the area will drop below freezing in the 4-6 pm range, maybe a bit
later in Sheridan county. With initial precipitation expected to
be rain, then some melting snow, expect any wet road surfaces to
flash freeze during this 4-6pm period. This will make the
afternoon/evening drive home increasingly difficult in many areas.
Went with a broad winter weather advisory to cover places expected
to pick up a tenth of an inch of precipitation or more in the
afternoon even if snow totals are expected to be fairly light due
to this potential flash freeze tomorrow evening.
Snowfall is expected to be heaviest in the areas along and south
of I-90 where gusty north to northeast winds will upslope into
area mountains. Probabilities for more than 3 inches is above 60
percent in these areas. Probabilities for more than 6 inches is
about 80 percent in Sheridan, 90 percent in Red Lodge, 70 percent
in Absarokee, and 100 percent over area mountains. Snowfall is
expected to fall heaviest during the night and into early Tuesday
morning, lingering over the southern tier foothills and mountains
into the afternoon. Snow should be done everywhere by 5pm Tuesday
afternoon.
Issued Winter Storm Warnings for the foothills and mountains.
Winds will be gusty to strong to begin the event which could
produce significant blowing/drifting snow. This threat should
diminish late Monday night as wind speeds subside. Overall Monday
night looks like a difficult travel period, consider delaying
travel until Tuesday afternoon or Wednesday if you can.
Temperatures will drop from the 50s and 60s around noon tomorrow
to the teens by late Monday evening. Highs on Tuesday will stay in
the teens and lower 20s. Chambers
Tuesday night through Sunday...
Tuesday night will be on the chilly side with temperatures in the
single digits for most areas. This will be a big change in
conditions from what we have been experiencing recently. This
could potentially cause issues with young livestock. Wednesday
will be windy across the region, especially the foothills. As high
pressure builds over Northwestern Wyoming and lee side troughing
forms over the plains of Montana, NAEFS is showing a strong Idaho
Falls to Lewistown pressure gradient of near 15mb forming. This
combined with 700mb winds approaching 50kts during this time
period and GFS soundings showing an inversion for Livingston
Wednesday morning, and you have a good setup for strong winds. The
gradient will orient itself in a way that will also bring strong
winds to Big Timber, Harlowton, and other locations along the
foothills. Thursday will see these winds continue, though likely
not as strong. The plains will also see breezy conditions during
this time period. By Friday, high pressure over Yellowstone Park
will weaken and higher pressure will move over the plains
allowing winds to weaken.
Wednesday will warm up fast into the 40s for most with a
westerly/northwesterly downsloping wind. This trend will continue
through the rest of the week with 50s and even some 60s possible
by Thursday and Friday. Ensemble clusters agree there will be a
pattern shift for the weekend. By Saturday we move into a more
southwesterly flow as a trough from the west begins to make its
way into the region. Most models show a low pressure system ahead
of the main Colorado Low but the track of any precipitation is
highly uncertain. The ECMWF is presenting the most impactful
scenario with a large low pressure system taking a very southerly
to northerly track dumping heavy snow in the Western Dakotas. A
slight shift to the west could bring this into Southeastern
Montana. This is just one scenario however and much is likely to
change. This pattern will bring about a cooldown in temperatures
but remaining seasonal. Torgerson
&&
.AVIATION...
Strong winds (50-60 kts) along the foothills are expected
tonight, especially at KLVM, through the morning. Confidence is
slightly lower for areas like KRED and KSHR where mountain wave
activity is possible during the overnight hours. Low level wind
shear can also be expected across the region into the morning. A
cold front will pass through the area mid day Monday bringing
widespread wind gusts of 30-40 kts while winds transition from
west to northeast. Rain will transition to snow and likely create
reduced visibilities. Mountain obscurations are possible. TS
&&
.PRELIMINARY POINT TEMP/POPS...
Mon Tue Wed Thu Fri Sat Sun
-----------------------------------------------------------
BIL 041/059 009/021 010/042 031/055 034/051 028/048 025/039
09/O 94/S 00/N 00/N 24/O 44/O 65/S
LVM 044/049 011/027 014/041 029/050 036/046 029/044 021/035
29/O 93/S 00/Q 01/N 46/O 66/S 65/S
HDN 038/061 008/023 007/044 026/058 031/056 026/052 021/040
19/R 94/S 00/U 00/B 12/R 34/O 55/S
MLS 040/053 006/018 008/042 027/057 031/051 026/047 022/037
16/O 52/S 00/N 00/B 00/B 22/S 33/S
4BQ 039/063 009/019 007/043 025/058 035/059 030/058 025/042
13/R 84/S 00/U 00/U 00/B 11/B 33/S
BHK 037/056 003/016 003/041 023/056 030/052 023/047 020/037
02/R 62/S 00/U 00/U 00/B 11/B 23/S
SHR 037/059 007/020 003/041 020/054 029/056 027/053 021/040
05/R +8/S 00/U 00/B 01/B 22/O 45/S
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...Winter Weather Advisory in effect from 5 PM Monday to noon
MST Tuesday FOR ZONES
29-30-34-36-40-42-57-58-63>65-139-141-170-172-173-228-235.
High Wind Warning in effect until 9 AM MST Monday FOR ZONES
56-138-169-171.
Winter Storm Warning in effect from 3 PM Monday to 5 PM MST
Tuesday FOR ZONES 56-66.
High Wind Warning in effect until 5 PM MST Monday FOR ZONES
63-67-68-141-172-228.
Wind Advisory in effect until 5 PM MST Monday FOR ZONES
65-66.
Winter Storm Warning in effect from noon Monday to 5 PM MST
Tuesday FOR ZONES 67-68.
Winter Storm Warning in effect from 5 PM Monday to 5 PM MST
Tuesday FOR ZONES 138-169.
Winter Weather Advisory in effect from 3 PM Monday to 5 PM
MST Tuesday FOR ZONE 171.
WY...High Wind Warning in effect until 9 AM MST Monday FOR ZONES
198-199.
Winter Storm Warning in effect from 5 PM Monday to 5 PM MST
Tuesday FOR ZONE 199.
Winter Weather Advisory in effect from 3 PM Monday to 5 PM
MST Tuesday FOR ZONE 198.
&&
$$
weather.gov/billings
Area Forecast Discussion
National Weather Service Des Moines IA
528 PM CST Sun Feb 25 2024
...Updated for the 00z Aviation Discussion...
.KEY MESSAGES...
- Exceptional warmth on Monday to break daily temperatures
records and make a run at all-time month of February records.
- Red Flag Warning in effect Monday for extreme fire danger due
to warm, windy, and very dry conditions.
- Sharp cold front on Tuesday will bring temperatures down 70+ degrees
overnight. Strong winds will accompany the cold front along
with rain and snow.
- Temperatures rebound back to near record territory again by
the end of the week.
&&
.DISCUSSION...
Issued at 239 PM CST Sun Feb 25 2024
Another dry and warm day across the area with temperatures
soaring into the low 60s already by 2 pm. A few high clouds have
moved across northern Iowa this afternoon as a weak wave passes
north of the area. Despite the light winds today a number of
fires have been detected across Iowa on radar and in satellite
imagery. This is certainly a concern as conditions on Monday
will be significantly worse.
So now lets discuss those Monday conditions. First, temperatures
tomorrow will smash daily records for February 26th by several
degrees (not to mention exceeding "normal" for this time of
year by 40+ degrees) as we warm into the 70s statewide. A few
locations in southern Iowa may even come close to 80 degrees! We
will also make a run a breaking all-time month of February
records at several sites. Temperatures, however, are the least
of our concerns. Model soundings and CAMs have becoming
increasing bullish with deep mixing on Monday. The HREF
indicates a wedge of relative humidity under 25% into the area
for several hours on Monday afternoon and soundings mix out and
become quite dry with dew points under 30F. Winds also become
strong with the HREF painting a widespread area with gusts of
30+ mph. RAP soundings show exceptional mixing and are likley
*quite* overdone. But, they do highlight an extreme example of
the mixing and associated wind/dewpoint potential for Monday.
As such, there is a chance the relative humidity drops lower
than currently forecast and that a few gusts higher than
currently forecast may occur. Altogether, a dangerous setup for
fire weather conditions and the reason for a Red Flag Warning
on Monday. Burning is strong discouraged and extra care should
be used for any activity that may result in a spark.
On Tuesday comes the much discussed trough originating out of the
Pacific northwest. Models today have continued with the slightly
slower trend noted on the previous shift, allowing temperatures
across central and southern Iowa to warm nicely ahead of the
front. With the incoming sharp cold front temperatures will vary
widely across the state on Tuesday, especially as the front
reaches northwest Iowa in the afternoon. In some instances parts
of northwest Iowa may only reach the upper 30s while southeast
Iowa warms into the low 70s. The front will swing across the
area from northwest to southeast late afternoon through the
evening with most precipitation trailing the front. Snow remains
likely, especially in northern Iowa where minor accumulations
are possible. Ensemble guidance continues to indicate a 30-40%
chance for 1" of snow in far northern Iowa while the area has a
high chance (80+%) for at least a dusting, mainly on grassy
surfaces. On the back side of the system soundings continue to
indicate some lose of ice introduction and a deep warm nose over
the much colder surface layer, so a wintry mix is possible as
precipitation is coming to an end. And lastly, winds become
rather breezy with gusts of 35-45 mph possible. The NBM came in
quite high across part of northern Iowa, however model sounding
are not quite that zealous so those gusts were tamped down.
Still, will need to monitor this period Tuesday evening into
Wednesday morning as it is near wind advisory criteria.
Behind the front Wednesday will be much colder, or near normal, with
highs in the upper 20s to low 30s. The day will start off even
colder with morning lows in the single digits and teens. With the
wind chill, it will feel more like the single digits (southeast
Iowa) to teens BELOW ZERO in northwest Iowa. This is remarkably
short lived as the ridge quickly rebuilds. 50s and 60s return
to finish the week with a run at more record breaking
temperatures by next weekend.
&&
.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 527 PM CST Sun Feb 25 2024
VFR conditions prevail through the TAF period. A brief window of
enhanced low level wind shear is expected Monday morning as a
corridor of stronger winds push through just off the surface.
Sustained southerly to southwesterly winds increase to 15 to 25
kts with gusts of 25 to 35 kts by mid to late Monday morning and
through the afternoon.
&&
.CLIMATE...
Issued at 235 PM CST Sun Feb 25 2024
.Forecast and Record Max Temps for Select Central Iowa Cities...
=============================================
| Monday MaxT (2/26) | Period
| Forecast Record/ | of
City | Year | Record
=============================================
Des Moines 77 70/1896 1878-
Lamoni 77 67/1988 1897-*
Mason City 68 57/1976 1903-
Ottumwa 75 64/1932 1923-
Waterloo 73 64/1896 1895-
=============================================
.Forecast and Record Max Temps for Select Central Iowa Cities...
=============================================
| Tuesday MaxT (2/27) | Period
| Forecast Record/ | of
City | Year | Record
=============================================
Des Moines 68 71/2016 1878-
Lamoni 72 72/1976 1897-*
Mason City 54 58/2016 1903-
Ottumwa 72 72/1976 1923-
Waterloo 66 64/2016 1895-
=============================================
.All-Time Record High February Temperatures for Select Central Iowa Cities...
=============================================
| February | Period
| All-Time High | of
City | Record/Year | Record
=============================================
Des Moines 78/1930 1878-
Lamoni 79/1930 1897-*
Mason City 66/1981 1903-
Ottumwa 79/2017 1923-
Waterloo 71/1921 1895-
=============================================
*Incomplete dataset
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning from 9 AM to 6 PM CST Monday for IAZ004>007-
015>017-023>028-033>039-044>050-057>062-070>075-081>086-
092>097.
&&
$$
DISCUSSION...Hagenhoff
AVIATION...Martin
CLIMATE...KCM
Area Forecast Discussion
National Weather Service Northern Indiana
535 PM EST Sun Feb 25 2024
.KEY MESSAGES...
- Severe weather threat Tuesday evening and overnight, dwindling
in intensity as we go later into the night. This is slightly
delayed from the previous forecast. Confidence is still
fairly low, and the primary threats would be hail/wind, heavy
rain. Isolated tornadoes are still possible, but appear less
likely than previous forecasts suggested.
-Blustery southwest winds Tuesday night will shift northwest
through Wednesday. Gusts up to 35 to 40 mph are possible at
times. Colder with chances for rain and snow Wednesday. Less
than 1 inch of snow accumulation is expected.
-Normal to above normal temperatures continue through the week,
particularly for Monday and Tuesday when highs reach into the
mid to upper 60s.
&&
.DISCUSSION...
Issued at 400 PM EST Sun Feb 25 2024
No major changes to the forecast, outside of updating the details on
the potential for severe weather Tuesday into Wednesday.
Have increasing pops Monday night into Tuesday morning with the
initial warm air advection/frontal boundary lifting northward.
Otherwise, dry conditions prevail. There is considerable uncertainty
regarding the precipitation late Tuesday morning into the afternoon.
Confidence remains fairly low as models are all over the place with
respect to the timing of the system. The latest runs have delayed
the timing slightly, which is the main change for this forecast. I
suspect models are overdoing the moisture quite a bit-so not quite
sure the widespread showers/storms that some models suggest for the
middle part of the day Tuesday will actually be there. The latest
high res guidance finally reaches into the 18-00z time for Tuesday-
and both the HRRR (through 18z Tue) and the HiResW-FV3 (through 00z
Wed) keep conditions dry over our CWA.
The severe weather threat will be greatest Tuesday evening, right as
the main surface low is approaching (over IL) and providing
sufficient lift to overcome the cap at surface-allowing us to access
the instability needed for a broader range of threats. The FV3 has
discrete cells develop across the western CWA (more southwest) at
the 00z time-which would prove to be a hail/wind threat, and perhaps
even isolated tornado. However, it`s possible the storms can`t
really access the surface instability and remain more elevated-which
would still be a hail threat given the steep mid level lapse rates
(7-8.5 C/km), strengthening wind shear (40-60 knots), and increasing
moisture transport (per an 850mb 55 knot jet). If the storms are
more elevated and the available moisture more limited than forecast,
the tornado threat lowers. The threat diminishes as we move eastward
overnight into Wednesday morning, and is more focused on damaging
winds. Winds around 925mb look to be around 40 knots, so wouldn`t be
surprised to see gradient winds (especially ahead of/behind the
cold front) gust to around that Tuesday night into Wednesday
afternoon-- particularly once we start cold air advecting. All
in all, I feel the `ingredients` for severe weather are a little
disjointed, so not totally on board with a specific solution as
of this writing.
Rain changes to snow as winds shift northwest behind the front
Wednesday, with temperatures falling from the 40s and 50s into the
30s and low 40s by the afternoon. Accumulations of less than 1 inch
are expected. We`ll see a little bit of a lake response before high
pressure inches in from the west late in the afternoon/evening-
bringing an end to our precipitation chances. Blustery NW winds
diminish overnight.
High pressure returns Thursday into Sunday, with highs gradually
warming into the 50s and low to mid 60s again by the weekend.
&&
.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 531 PM EST Sun Feb 25 2024
No significant changes to the TAFs for this issuance. Radar
returns are noted over southern Michigan, but 20-degree dew
point depressions are too dry for precipitation to reach the
surface. SCT to BKN mid-level clouds will pass through these
next several hours, but confidence is high for VFR conditions to
prevail. Light wind tonight followed by a diurnal uptick in
wind Monday late-morning.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...None.
OH...None.
MI...None.
MARINE...None.
&&
$$
DISCUSSION...MCD
AVIATION...Brown
Area Forecast Discussion
National Weather Service Louisville KY
935 PM EST Sun Feb 25 2024
.KEY MESSAGES...
* Turning very mild and breezy with highs in the low to mid 70s on
Monday and Tuesday. Some warm minimum record temps likely.
* Scattered showers and thunderstorms will be possible Tuesday
morning ahead of an approaching storm system. Brief heavy rain and
small hail the main threats.
* A cold front will bring a chance of thunderstorms and gusty winds
Tuesday night into Wednesday morning. Although confidence remains
low, strong to potentially severe storms cannot be ruled out.
&&
.UPDATE...
Issued at 935 PM EST Sun Feb 25 2024
Last several runs of the HRRR and RAP continue to show showers
moving west to east across a more northerly track than the current
southern KY activity. Activity is forecast to start over southern IL
in the next hour. GOES Sounder data is showing an increase in PW in
that region and over the past 30 minutes have started to see a few
clouds pop up over far SW IL and SE MO, roughly along the western
edge of the PW gradient. The most unstable air remains across
southern KY, so will keep thunder out from the pops I`ve increased
in the north, but have gone up to 30-40 PoP in a Shepherdsville to
Nicholasville line over central KY, with peak values in the 6-9Z
time frame. Updated products will be out shortly.
Interesting to note, that despite the continued large dewpoint
depressions over the region, the Russell County and both Warren
County Kentucky Mesonet stations did report measurable rainfall!
Issued at 722 PM EST Sun Feb 25 2024
Have had a couple of ticks of lightning from GLM data as well as
NLDN across southern KY. A few echoes got thick enough to generate
some brief ice, with a couple of reports of pea-sized hail in JKL`s
area in the last hour. Continued trending toward the HRRR/RAP time
lapse models to update PoPs, which increases chances for later
across more of the region. Still a lot of low-level dry air to
overcome. GOES derived sounder data shows the current east-west
batch of cells is forming along a PW-gradient that looks to be
steadily moving north and in an area with Total Totals in the 45-50
range. Will send out updated products shortly.
Issued at 615 PM EST Sun Feb 25 2024
Satellite and radar indicate some very elevated convection
developing in the past hour or two over southern KY. Near surface
dry layer should limit chances for measurable precipitation. It`s
coming about an hour or two earlier than HRRR/RAP guidance
suggested, and radar returns show some higher returns as well.
Wouldn`t be surprised to sprinkles make it to the surface under
those higher returns. Given the earlier start, did bump up pops a
little for later this evening, capping generally at 20 percent or
less though. The best chance to measure anywhere will be across our
Lake Cumberland counties late this evening.
&&
.SHORT TERM /THROUGH MONDAY/...
Issued at 308 PM EST Sun Feb 25 2024
Through the short-term, the basic set-up changes very little. Upper
west-northwest, almost zonal, winds remain overhead as a surface low
sits over the Plains, and high pressure lies along the Atlantic
Coast. The pressure gradient in between will keep warm air advection
over the Lower Ohio Valley through the period. This along with a
passing shortwave tonight will cause some additional mid-layer cloud
cover. Model soundings keep the low levels dry, so like today, this
will probably result in some sprinkles, but not much more. The best
chances for a sprinkle or two will be across southern Kentucky. Some
lighter cloud cover will make it farther north. This along with WAA
will help limit falling temperatures to the low 40s in our northern
areas to the low 50s across our south.
Tomorrow, skies are expect to clear early in the morning, making for
a mostly sunny day. With WAA continuing and with a warm starting
point from tonight`s warm lows, we should overachieve on high
temperatures. Expecting low to mid 70s across the CWA.
&&
.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
Issued at 300 PM EST Sun Feb 25 2024
Monday night - Wednesday...
Monday night starts off dry, however we will begin to see an
increase in precipitation activity the closer to sunrise we get. The
exit region of an intense upper jet overspreads our area toward
dawn, with an associated low level jet response around 30-40 knots
as a trigger. Do expect a strong inversion around 850 mb, however
steep lapse rates above this feature will yield good probabilities
for around 500 J/kG of MUCAPE above the LFC. Some data does suggest
higher values, which would most likely be across our NW. Given the
amount of expected forcing and what appears to be enough elevated
instability, do expect we could see a few more organized storms in
the presence of favorable deep layer shear vectors above the
inversion. The main threat from any stronger storm would be brief
heavy rain and some small hail likely. Marginally severe hail can`t
be ruled out if we do get some organized stronger updrafts. Will
continue scattered coverage mention along with t-storm mention in
the going forecast. Given the steady southerly flow and a good
amount of sky cover, expect the overnight to be pretty mild in the
mid 50s to around 60, which will likely put some warm min records in
jeopardy for early Feb 27. See Climate section of discussion.
Scattered showers and storms lift off to the NE through the day on
Tuesday, with a drier trend setting up from SW to NE as the warm
sector gets more established over the area. Will also see gusty SW
winds and rapidly warming temperatures as a result of this warm
sector/deeper mixing. Looking for low to mid 70s for highs, which
could also flirt with some Feb 27 records. See Climate section
again. For context, Tuesday probabilities of temps reaching 75
degree range from 30-50% east of I-65, and 50 to 70% west of I-65.
Speaking of the gradient winds, fairly high probabilities are
currently showing up in the data of seeing some gusts in the 35 to
45 mph range, however this is some uncertainty with cloud cover into
Tuesday afternoon that hurts confidence just a bit on whether we
will need a Wind Advisory. At this point, leaning toward the need
for one (at least along and south of the Ohio River) as the deeper
parts of the warm sector usually get clearer than expected. If that
occurs Tuesday PM, we should be in line for some fairly widespread
35 to 45 mph gradient wind gusts.
By Tuesday night, another surge in the exit region of the intense
upper jet overspreads our area, with stronger response in the low to
mid levels (a stronger 50 knot low level jet). This occurs ahead of
a surface cold front that extends from a surface low moving into the
Great Lakes region. Timing of the strong cold front is still in
question, and this will play a role in how much instability we might
have to work with as early Wednesday morning convection organizes
upstream and moves into the area. Faster arrival with the cold front
pushing through Wed. morning doesn`t allow for much, if any, near-
surface based instability. On the other hand, slightly slower
arrival likely brings a somewhat organized linear feature into our
NW before sunrise, and then allows for some
destabilization/reintensification across our SE CWA later Wednesday
morning into the afternoon. This secondary solution is suggested by
the GFDL C-Shield 25/00z run, and seems plausible given the setup.
Either way, this is another low CAPE, high shear setup that will be
dependent on destabilization to get any notable severe threats.
Given the lower confidence in timing and ultimate destabilization,
this has a Marginal type of feel at the moment with isolated
damaging wind gusts the main threat in addition to brief heavy
rainfall. A brief, spin up tornado threat could also develop with
QLCS activity taking advantage of the meager instability as low
level hodographs appear impressive in the strongly sheared
environment. The low level thermal profile is the big question mark,
no doubt. Record warm minimums will likely be broken again on
Tuesday night for some sites. See Climate section a third time.
Some brief heavy rain will be possible with the strong moisture
transport late Tuesday night into Wednesday, but overall QPF totals
don`t seem to be screaming given the overall progressive nature of
this system. Therefore, think the overall flood threat remains low
outside of a few nuisance issues.
We will also have to watch p-type toward the end of the event as
cold air really comes crashing in. Not paying much attention to this
at the moment though as very mild antecedent conditions should
outweigh any concerns with a brief p-type changeover at the end.
Will keep an eye on it.
Wednesday Night - Thursday...
Should be dry in the post-frontal/post-trough axis regime by
Wednesday night with gusty NW winds slackening as surface high
pressure builds in. Temperatures back in the mid 20s may be a shock
to the system by Thursday morning, after near-record/record highs on
Tuesday. Outside of the cold start, Thursday is dry with temps
recovering to the mid 40s for most.
Thursday Night - Sunday...
Low confidence in this time frame as a southern stream disturbance
could bring some rain chances as early as Thursday night and as late
as Friday night, mainly across the southern CWA. Milder temps back
in the 60s and mostly dry conditions look like a good bet for the
bulk of the weekend. Although will continue to carry some small pops
at times.
&&
.AVIATION /00Z TAFS THROUGH 06Z TUESDAY/...
Issued at 610 PM EST Sun Feb 25 2024
Have a band of elevated convection appearing on radar and satellite
near the KBWG terminal this hour. Very dry low levels should keep
this to perhaps sprinkles over southern KY in the next few hours.
Another band could develop closer to KLEX overnight, but with
similar results. Otherwise, looking at some low-level wind shear
overnight, with southwest winds aloft at 40-45 kts in the BWG/LEX
area. SDF/HNB still look to stay just north of this, but CONSShort
guidance does bring 30-35 kt southwesterly winds to SDF...just under
criteria for LLWS. These higher winds should diminish around or just
before daybreak Monday.
&&
.CLIMATE...
Issued at 352 PM EST Sun Feb 25 2024
================== Near-Record High Temperatures ==================
Monday 2/26/2023
Max T Fcst/Record (Year)
Louisville: 75/76 (2000)
Bowling Green: 75/78 (1917)
Lexington: 71/76 (1944)
Tuesday 2/27/2023
Warm Min T Fcst/Record (Year)
Louisville: 58/55 (1876)
Bowling Green: 59/54 (1995)
Lexington: 55/54 (1996)
Tuesday 2/27/2023
Max T Fcst/Record (Year)
Louisville: 71/75 (2023)
Bowling Green: 72/78 (2023)
Lexington: 70/74 (2023)
Tuesday 2/28/2023
Warm Min T/Record (Year)
Louisville: 60/57 (1904)
Bowling Green: 61/64 (1895)
Lexington: 59/54 (1955)
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...None.
IN...None.
&&
$$
UPDATES...RJS
SHORT TERM...KDW
LONG TERM...BJS
AVIATION...RJS
CLIMATE...BJS