Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/22/24
Area Forecast Discussion
National Weather Service Cheyenne WY
430 PM MST Wed Feb 21 2024
.KEY MESSAGES...
- Rain and snow showers will move across the area this afternoon
through early Thursday morning, with additional accumulations
expected along and west of the Laramie Range.
- A fairly widespread high wind event is looking increasingly likely
for the wind prone and nearby locations of southeast Wyoming
for the weekend and Monday.
- Much colder temperatures and increasing chances for widespread
snow will develop Monday night and Tuesday.
&&
.SHORT TERM /THROUGH FRIDAY/...
Issued at 300 PM MST Wed Feb 21 2024
A springlike atmosphere is present across the area this afternoon as
messy storm system moves across the area. A disorganized shortwave
is pushing across the area today and kicking off another round of
precipitation. Satellite imagery shows a plume of moisture pushing
over the area along this shortwave axis. Additionally, some weak
instability is present across the area this afternoon per the latest
mesoanalysis with SBCAPE exceeding 250 J/kg over much of far
southeast Wyoming and southwest Nebraska. Combined with the vort-max
passing over aloft and some modest frontogenesis associated with the
mid-level frontal boundary stalled over our area, fairly widespread
precipitation is filling in the radar this afternoon. Along and west
of the Laramie range, this is falling as snow. A convergence
boundary moving into Carbon county at this time is flaring up a line
of more intense snow shower activity that is displaying some decent
convective growth on satellite imagery. A few lightning strikes have
even been observed just SW of Rawlins with this line. While a Winter
Weather Advisory remains in effect to capture some of this activity,
there is a possibility snow squall products could be needed is this
progresses eastward. For now, expect this to traverse the interstate
at least into far western Albany county and bring a rapid drop in
visibility, briefly heavy snowfall, and gusty winds. Further east,
temperatures are warm enough to support rain showers, which have
finally saturated the lower atmosphere and are now reaching the
ground over the last few hours. Another few lightning pulses have
been observed over Laramie county over the last hour. Expect this
activity to expand in coverage and shift eastward through the early
evening. There is enough moisture in the middle atmosphere for
localized areas to manage a few tenths of rainfall out of these
showers, along with the possibility for ice pellets/graupel in the
more convective cells. Once the front pushes through this evening,
expect rain to transition to snow between 5PM and the end of
activity for areas east of the Laramie range. Higher areas such as
along the Cheyenne ridge could pull a dusting to an inch or so out
of this activity.
Heading into tonight, guidance shows a secondary shortwave just
trailing the first this afternoon. RAP forecasts show a convergence
boundary along this secondary trough axis dropping down from the
north overnight. This may kick up a second round of snow activity in
Carbon and Albany counties, which is consistently shown in the
latest round of HiRes guidance. However, models differ in exactly
where this area will set up. Earlier HRRR runs set up a persistent
band of precip right over Interstate 80 from Laramie to Rawlins into
Thursday morning, but the following few runs have shifted this
slightly south, more into the Snowy Range. With most showing some
additional snow along I-80 though, decided to extend the
Arlington/Elk Mountain Winter Weather Advisory until 9AM Thursday to
account for this possibility. Will need to monitor this into the
evening and overnight, as it could spread east to the Laramie Valley
and South Laramie range, but didn`t have the confidence add this
areas at this time.
The convergence boundary finally shifts south by the late morning on
Thursday, which should bring snowfall to an end. The middle
atmosphere may remain fairly moist even behind the trough axis
tomorrow though, and with steep lapse rates still present, HiRes
guidance shows another round of rain/snow shower activity developing
during the afternoon hours. Don`t expect this to amount to much, but
a quick visibility drop and dusting to an inch or so of accumulation
will be possible. Overall temperatures Thursday will be cooler than
today, but just down to near normal for this time of year. Expect
dry air to finally move in Thursday night, which should bring an end
to light snow showers and clouds in the mountains by Friday morning
or early afternoon. Otherwise, look for a sunny day Friday with
breezy westerlies beginning to increase once again. GFS-based in-
house guidance suggests probabilities of around 40% for the
wind prone areas, but it`s worth noting the GFS is running a
little hot compared to other guidance. For now, elevated winds
look likely, but will need to monitor for the high wind
potential.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Issued at 300 PM MST Wed Feb 21 2024
Friday night/Saturday...Northwest flow aloft strengthens
significantly, with an increasing area of 700 mb winds in excess of
50 knots developing, along with our local wind models showing
possible strong winds, and Craig to Casper 850/700 mb gradients
increasing over 60 meters, thus we will likely see the wind prone
locations and even more nearby locations in southeast Wyoming
approaching or exceeding high wind criteria, especially during the
daytime. The warming trend will continue with 700 mb temperatures
near 0 Celsius yielding high temperatures in the upper 30s to mid
40s west of I-25, with 50s elsewhere.
Sunday...Strong winds will likely become even more widespread across
southeast Wyoming with tight low and mid level gradients, as well as
700 mb wind progs showing 50-65 knots winds near the mountains, and
Craig to Casper 700 mb height gradients over 60 meters, along with
our other local high wind models suggesting near high wind criteria.
Continued relatively mild for late February with 700 mb temperatures
near 0 Celsius and downslope warming.
Monday...Looks like a carbon copy of Sunday based on low and mid
level gradients and progged 700 mb winds exceeding 50 knots along
the spine of the mountains. Thus, will likely continue the
possibility of high winds for the wind prone locations, as well as
other nearby locations in Rawlins, Douglas, Laramie and Cheyenne.
Mild temperatures continue in the warm sector ahead of the
approaching cold front.
Tuesday...Major changes to the weather pattern are on tap as the
next progressive shortwave trough aloft carves itself out over
Montana and Wyoming, with a potent Canadian origin cold front
progressing southward across our counties early in the day, bringing
colder temperatures, which may need to be adjusted colder in the
next few days. The combination of lift provided by system dynamics,
orographics and upslope, and a deep moist airmass should help
produce widespread snow, with possible warning criteria snowfall for
our mountains and perhaps advisory criteria snowfall for some of the
lower elevations.
Wednesday...The progressive shortwave trough aloft moves across and
to the south of our forecast area, with clearing skies developing.
Another cold day expected with 700 mb temperatures near -10 Celsius,
and brisk north to northwest winds developing with the progged low
and mid level gradients.
&&
.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 425 PM MST Wed Feb 21 2024
Area of snow showers first impacting the KRWL this afternoon
will expand to the east and bring deteriorating conditions to
the KLAR and KCYS terminals toward the late afternoon with MVFR
conditions expected. While the precipitation across the Wyoming
terminals will be in the form of snow showers, expect mostly
rain showers with the possibility of a rumble of thunder for the
Nebraska terminals toward the early evening hours. Brief periods
of MVFR VIS possible as rain showers pass over Nebraska terminals
with the highest confidence of this occurring at the KBFF,
KAIA, and KSNY terminals. All shower activity is forecast to
taper off after 07Z in most locations, potentially lasting until
15Z at KLAR and KRWL. Gusty west to northwest 20 to 30 knot winds
expected across southeast Wyoming and western Nebraska after
18Z.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...Winter Weather Advisory until 11 PM MST this evening for
WYZ105-109-113.
Winter Weather Advisory until 9 AM MST Thursday for WYZ110.
Winter Storm Warning until 5 AM MST Thursday for WYZ112.
Winter Weather Advisory until 5 AM MST Thursday for WYZ114.
NE...None.
&&
$$
SHORT TERM...MN
LONG TERM...RUBIN
AVIATION...LEG
Area Forecast Discussion
National Weather Service Fort Worth TX
623 PM CST Wed Feb 21 2024
...New Short Term, Aviation...
.SHORT TERM... /NEW/
/Through Thursday Afternoon/
Current RAP analysis and mid-level water vapor satellite imagery
shows the axis of the deamplifying mid-level ridge has shifted
over the Lower Mississippi Valley today. The feature responsible
for the breakdown of the ridge, a compact shortwave trough
translating across the Four Corners region, has encouraged a low-
level mass response in the form of weak surface cyclogenesis in
eastern CO this afternoon. Coupled with surface high pressure over
the eastern GOM, there has been a rapid increase in southerly
breezes with wind speeds still peaking around 15 to 20 MPH and
occasional gusts of 25+ MPH. A slight uptick in sustained wind
speeds with scattered gusts up to 35+ mph may occur this evening
and especially overnight, particularly in those areas nearest the
passing surface low (northeast of the Metroplex, near the Red
River). As discussed previously, though a few locations may meet
or exceed the threshold for a Wind Advisory the sparse coverage
and expected short duration of these occurrences precludes the
need for wind headlines at this time.
Warm advection will continue in earnest this evening as a strong
LLJ develops ahead of the eastward tracking low. Similar to what
was observed early this morning, low clouds are expected to expand
in coverage across primarily the southeastern half of the region
through the pre-dawn hours, aligning with the southwest to
northeast oriented LLJ. In contrast to earlier today, this time
the well-mixed boundary layer should inhibit fog potential.
Overnight temperatures will also be a degree or two warmer than
the last night with lows in the mid 50s to low 60s. The passing
surface low will push its attendant dryline/cold front into North
and Central Texas on Thursday bringing a WNW to NW wind shift and
cooler, drier air to the region. Tomorrow`s high temperatures will
ultimately be a timing game between when the front moves through
and how much prefrontal heating occurs with warm and dry West
Texas air preceding the FROPA. There will likely be as much as a
10-15 degree SE to NW temperature gradient Thursday afternoon with
forecast highs in the low/mid 70s primarily NW of the DFW
Metroplex to the low/mid 80s south and east of a Canton to
Goldthwaite line. Drier downsloping northwesterly flow is expected
in the wake of the front.
12
&&
.LONG TERM... /Issued 215 PM CST Wed Feb 21 2024/
Update:
The only changes to the long term forecast were slight
adjustments to temperatures on Monday and Tuesday where the
operational NBM is still ranging between the NBM10th and NBM25th
percentiles, continuing the trend upwards for highs where several
locations out west could reach into the 90s early next week.
Well above-normal temperatures will be the dominant story for the
long term forecast, save for Thursday and Friday as a weak, rain-
free cold front sweeps across North and Central Texas. Highs on
both of these days will still be above seasonal norms however,
ranging in the upper 60s to mid 70s. Strong southerly flow will
become established once again over the weekend, leading to warm,
dry, and breezy conditions through the start of next week. Rain
chances and cooler weather seem to loom over the horizon with the
passage of another cold front through mid-week next week, but
details are difficult to resolve 7+ days out. Continue to check
back for updates as the forecast becomes more refined.
Reeves
Previous Discussion:
/Thursday Night Onward/
A cooler and drier airmass will enter behind the cold front
Thursday night, though temperatures will still remain 5 to 10
degrees above normal Thursday night and Friday. The post-frontal
ridge axis will settle across Central Texas Friday night, making
for a good radiative cooling environment. Temperatures will fall
into the lower and mid 40s for most locations, though some of the
lower spots may drop into the 30s by daybreak Saturday. A warm-up
will begin during the day Saturday as the surface ridge shifts
east of the area, return flow begins, and a mid/upper ridge re-
strengthens overhead. High temperatures will reach the mid 70s on
Saturday and upper 70s to lower 80s on Sunday.
The next weather features to focus on will be a pair of upstream
shortwaves within a split flow regime, which will begin to make
their approach from the west and northwest late weekend/early next
week. The northern shortwave will drop southeast from the Pacific
Northwest to the Great Basin, while the southern shortwave moves
from the eastern Pacific into Baja California late Sunday through
late Monday. Their combined effects on the synoptic scale pressure
gradient will make for warm and windy weather starting Sunday.
Monday may end up being exceptionally warm, as it looks like
dryline intrusion may occur across the western half of the area.
The operational NBM actually falls between the NBM25th and NBM10th
percentiles, leading me to lean heavily on the warmer side of
guidance for that day. There may be several 90+ degree highs that
afternoon, with the best chance being along and west of Highway
281. Either way, warm, dry and breezy weather will create an
elevated grass fire threat for areas along and west of I-35
Monday afternoon.
The two shortwaves will merge over the southern Rockies Monday
night, creating a larger single shortwave trough, which will
approach from the west on Tuesday. A cold front accompanying the
upper trough will approach from the northwest as the upper trough
approaches from the west. Warm and windy weather will continue
into Tuesday as the pressure gradient remains quite narrow in
advance of the cold front. Veered surface winds ahead of the front
will limit moisture return, but there should still be enough
moisture and lift to generate scattered rain showers late Tuesday
into Wednesday as both the front and upper level system sweep
across the forecast area. Will remain conservative with POPs due
to limited moisture, with only slight chances advertised across
the eastern half of the region for now. Cooler and drier air will
again enter in the wake of departing system, but it looks once
more like temperatures will remain above-normal as we close out
February.
30
&&
.AVIATION... /NEW/
/00Z TAFs/
We have generally maintained ceiling and wind trends introduced
during the previous TAF cycle with VFR and gusty south flow
prevailing at the D10 terminals and ACT this evening. Peak gusts
of 30 KTS may be possible at the Metroplex TAF sites (especially
at DFW/DAL) through 08Z as a surface low pressure system passes
nearby. VFR conditions will eventually give way to another surge
of stratus spreading northward tonight with the western edge of
the MVFR ceilings likely settling over the D10 terminals. Have
shifted the MVFR at our western Metroplex sites (FTW/AFW) to a
TEMPO group with this update as guidance continues to favor a
southwest to northeast orientation to the cloud deck and these
airports will likely be on the fringes with only briefly lowering
ceilings.
Low level winds should start gaining an increasingly westerly
component (230-250) during the pre-dawn hours which will help
quickly erode the MVFR stratus after 12Z. However, there is some
guidance that is indicating the drier air could arrive sooner than
currently anticipated so trends/guidance will continue to be
monitored as ceiling improvement may need to be moved up. Cigs are
expected to be slower to lift/clear at KACT with MVFR lingering
through ~ 15Z Thursday. The cold front associated with the passing
low pressure system should reach the D10 terminals before mid-day
accompanied by a NNW wind shift with speeds around 10-15 KTS
through the end of the current TAF period.
12
&&
.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth 59 77 49 71 47 / 0 0 0 0 0
Waco 60 82 50 70 42 / 5 0 0 0 0
Paris 60 76 47 69 43 / 5 0 0 0 0
Denton 55 75 45 70 41 / 0 0 0 0 0
McKinney 59 76 47 70 43 / 0 0 0 0 0
Dallas 61 79 50 72 48 / 0 0 0 0 0
Terrell 59 78 47 70 43 / 0 0 0 0 0
Corsicana 61 81 50 70 45 / 5 0 0 0 0
Temple 59 84 49 71 43 / 5 0 0 0 0
Mineral Wells 54 76 45 71 42 / 0 0 0 0 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Area Forecast Discussion
National Weather Service Goodland KS
459 PM MST Wed Feb 21 2024
.KEY MESSAGES...
- Near critical to briefly critical fire weather conditions are
possible south of Interstate 70 the rest of this afternoon.
Relative greatest potential for critical fire weather
conditions are in Cheyenne County, Colorado.
- Showers may bring sporadic wind gusts in excess of 50 mph
across western portions of the area through the evening.
- Breezy north winds will develop in the wake of a cold frontal
passage tonight. Gusts of up to 40 mph will be possible.
- Elevated fire weather conditions are possible Saturday
afternoon due to the combination of low humidity and gusty
west winds.
- A stronger system will impact the area early next week. It
will bring a risk of critical fire weather conditions on
Monday followed by a chance for light snow Tuesday and
Wednesday. Some blowing snow and travel hazards will be
possible.
&&
.UPDATE...
Issued at 453 PM MST Wed Feb 21 2024
Made some slight southward trends in the pops mainly down to
around the I-70 corridor in Kit Carson and Sherman county as
some showers are moving into the CWA. RAP soundings show
inverted v profiles through at least the Highway 27 corridor.
SPC Mesoanalysis also shows 500-900 j/kg of DCAPE and unstable
low and mid level lapse rates around 8.5-9C which should be
efficient enough for the potential for a rogue wind gust in
excess of 50 mph with any decaying convection. Not overly
concerned on the lightning aspect as SBCAPE and MLCAPE is
minimal at best. There is some uncertainty with the eastward
extent of the showers and potential hazards as a cold front
currently in the NE Panhandle moves to the SE and eventually
across the CWA overnight.
&&
.SHORT TERM /THROUGH SATURDAY NIGHT/...
Issued at 200 PM MST Wed Feb 21 2024
Upper ridge axis has moved east of the area with southwest flow
aloft. Embedded weak shortwave trough will move through tonight
bringing a few light showers and a period of gusty north winds.
Showers will not be impactful amounting to only a few
hundredths, but evaporative cooling may enhance surface winds
with gusts over 40 mph possible by around 03z and continuing
through about 09z before diminishing. Low temperatures will be
in the 20s.
Thursday and Friday will be under northwest flow downstream of
a strengthening ridge over the Pacific northwest. Both days will
be dry and mild with highs in the 50s. Both days will also be
breezy, with northwest winds on Thursday gusting 20 to 30 mph
in the morning before diminishing in the afternoon. Winds on
Friday may increase a bit as a subtle shortwave trough/wind max
moves through the upper flow, with models showing gusts of 30 to
40 mph possible, though vary in where those max gusts might
occur. Low temperatures will mainly be in the 20s.
On Saturday, the western ridge weakens and moves south,
resulting in more of a zonal flow across the central plains. It
will continue to be dry and a bit warmer due to more of a
westerly downsloping surface wind. Highs will be in the 60s with
those west winds gusting 20 to 30 mph. May approach elevated or
near critical fire weather conditions with relative humidity
dropping into the mid to upper teens in most locations by
Saturday afternoon. Lows Saturday night will be in the 20s and
30s.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
Issued at 200 PM MST Wed Feb 21 2024
Zonal flow continues on Sunday over the ridge which has moved to
the southern plains. Temperatures will warm into the upper 60s
or lower 70s. Elevated fire weather conditions may develop due
to low humidity in the afternoon, but winds appear to be lacking
for critical conditions. Lows will be in the 30s Sunday night.
Next upper trough will dig into the Pacific northwest on Monday,
the central and northern Rockies on Tuesday, then into the
central plains on Wednesday. It will bring gusty winds, colder
temperatures and a chance of light snow early next week.
For Monday, main concern will be fire weather. Temperatures will
climb into the 70s throughout the entire area. Surface winds
will be out of the west with considerable downslope warming and
drying of the low levels. Models probably not lowering dew
points enough at this time range, and humidity already in the
middle teens. Models currently show strongest winds in Colorado
and southwest part of the area, with gusts over 40 mph, but
lower wind speeds further east in Kansas and Nebraska, with
gusts more in the 20 to 30 mph range. So, greatest confidence in
reaching critical fire weather conditions will be in Colorado
and near the Colorado and Kansas border area, particularly south
of Interstate 70.
On Tuesday, will see best chance of precipitation as the
associated cold front moves through the area. Models differ
in the timing of the front, with the GFS about 12 hours faster
compared to the ECMWF. Highs will be dependent on timing of the
front, with temperatures well into the 60s or even 70s ahead of
it, but tumbling into the 40s and 50s behind it. The GFS
solution would see falling afternoon temperatures and rain
changing to snow as the cold air filters in behind the front.
The snow would continue through Tuesday night. In addition,
northerly winds gusting 30 to 40 mph may accompany the snow.
Although accumulations of only an inch or two are forecast, the
combination of light snow and wind would result in blowing and
drifting, causing travel hazards. The GFS has the light snow
lingering into Wednesday morning with gradually diminishing
winds. As mentioned, the main difference between the GFS and
ECMWF would be to delay precipitation chances into Tuesday
night, then continuing through Wednesday. ECMWF also shows gusty
north winds accompanying the snow and similar snow amounts. It
is worth noting that the Canadian GEM has a faster frontal
passage, and both less snow and less wind, with lower impacts.
Temperatures on Wednesday will be highly dependent on how much
snow cover actually materializes, but more snow would result in
colder temperatures. Current blended forecast may be a bit
optimistic with 40s for highs, and would not be surprised to see
temperatures at least 10 degrees colder than that.
&&
.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 407 PM MST Wed Feb 21 2024
Showers are moving into eastern Colorado currently and are
forecast to impact or come near the KGLD terminal; the potential
is there for gusty winds to occur with the showers due to
inverted v sounds, 500-800 j/kg of DCAPE. Currently have 25
knots in the tempo, but with the parameters in place think there
could be the potential for a very localized 40+ knot gust to
occur. These showers currently are not forecasted to impact
KMCK.
The next focus will then be on the incoming cold front where
winds will become breezy for a few hours as there turn to the
NNW. Introduced LLWS into the TAF as the front moves closer in
proximity to each terminal.
Breezy winds look to continue throughout the day Thursday
gusting 20-25 knots at each terminal.
VFR conditions are currently forecast to continue although a
brief period of MVFR may occur if a shower were to move over the
KGLD terminal.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...None.
CO...None.
NE...None.
&&
$$
UPDATE...Trigg
SHORT TERM...024
LONG TERM...024
AVIATION...Trigg
Area Forecast Discussion...Updated
National Weather Service Lincoln IL
835 PM CST Wed Feb 21 2024
.KEY MESSAGES...
- Main threat of any stronger storms overnight appears focused
along a Galesburg-Kankakee line, though overall potential
remains low (around 5% chance of severe hail).
- Near record warmth is likely as the end of the month approaches,
with widespread highs in the 70s Tuesday.
- Thunderstorm chances for Tuesday and Wednesday are on the
increase, though the extent of any severe weather threat still
remains hazy.
&&
.UPDATE...
Issued at 834 PM CST Wed Feb 21 2024
Continue to monitor the chance for thunderstorms overnight
associated with a low level jet over the region. KILX VWP
indicates 45-50 kt mid level southerly flow is already in place
this evening which is helping to transport moderate instability
across central Illinois over the next several hours. 00Z KILX
sounding does indicate there is some work to be done, however,
with dry conditions below around 600mb and PWat of only 0.68
inches. There are steep mid-level lapse rates of 7.9C/km and
high-res guidance continues to show gradual saturation with
moderate instability atop a 925mb warm nose eventually
contributing to some pockets of around 1500 J/kg MUCAPE. There may
be a small window after midnight for ingredients to align and
allow some stronger, elevated thunderstorms before the nose of the
LLJ veers into Indiana. Latest few runs of the HRRR have been
trending later and lower coverage of any severe threat. If any
stronger storms do develop, the primary hazard will be marginally
severe hail.
Deubelbeiss
&&
.SHORT TERM... (Through Late Thursday Night)
Issued at 245 PM CST Wed Feb 21 2024
Early afternoon temperatures in the low-mid 60s were widespread
over the forecast area, despite the thickening high clouds near
and north of I-74. Regional surface obs show dew points in the 50s
have crept into southeast Missouri, and should advect northeast
into parts of central Illinois by late evening. With the warm
front expected to be roughly along a Beardstown-Bloomington line
overnight, areas south of there will only drop into the lower 50s,
with lows 45-50 to the north.
Latest HRRR is showing some elevated convection developing over
southeast Iowa by late evening, tracking in a general eastward
fashion over the northern CWA after midnight. No changes have been
made to the recent Day1 severe outlook, continuing to highlight a
level 1 (marginal) risk of some large hail. Areas near and north
of I-74 appear to have the best chances of this occurring. Any
severe threat will be out of the area by sunrise.
Main upper wave sweeps across the region on Thursday. Highest
rain chances remain concentrated in the morning hours, though
overall PoP`s were reduced a bit across the central and western
parts of the forecast area. With the mild start and cooler air
lagging behind a bit, highs in the 55-60 degree range still appear
reasonable.
Geelhart
.LONG TERM... (Friday through Next Wednesday)
Issued at 245 PM CST Wed Feb 21 2024
A brief shot of cooler air is still on tap to start the weekend,
as a shortwave moves across the Midwest. Some model differences on
the amount of moisture available with this feature, though
potential for some flurries doesn`t appear unreasonable at this
point. Have added some 15% PoP`s near and north of I-74 for Friday
night as a result.
Early next week continues to look to be more like late April
rather than late February. 850 mb temperatures in the mid teens
Celsius arrive by early Tuesday, and stand a decent chance to
linger into Wednesday before a strong upper trough sweeps over the
central CONUS around mid week. Latest ECMWF extreme forecast index
is up to 0.9 for highs Tuesday, signifying a highly anomalous
event. 60s return as early as Sunday, and widespread highs in the
low-mid 70s are now expected on Tuesday. Record highs over the
area on Tuesday are generally in the 70-75 degree range, and some
monthly warm-low temperatures could be in jeopardy as well.
Regarding the thunderstorm potential next week, some timing
differences have been emerging in the longer range models, with
how fast the cold front passes as the upper trough digs over the
Plains. Last evening`s run of the CSU probabilistic severe weather
forecast highlighted a fairly large area from the Midwest into
eastern Texas, which lines up with the GFS axis of CAPE`s >1000
J/kg from this morning`s run. The new ECMWF is a bit slower and
lingers more of a threat into Wednesday as well. Main adjustment
to the initialized blends in this part of the forecast was to
increase the chances of thunder to around 30-40%.
Geelhart
&&
.AVIATION... (For the 00z TAFs through 00z Thursday Evening)
Issued at 533 PM CST Wed Feb 21 2024
A warm front will set up along the I-74 corridor late this evening
and overnight and will serve as the focus for scattered showers
and thunderstorms. Low pressure will move across the region
overnight bringing IFR ceilings and light and variable winds.
Winds will turn NE to N behind the departing low and anticipate
conditions to return to VFR around midday Thursday.
Deubelbeiss
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Area Forecast Discussion
National Weather Service Northern Indiana
550 PM EST Wed Feb 21 2024
.KEY MESSAGES...
- Scattered showers and storms arrive after midnight tonight,
with an isolated severe risk in west-central Indiana (with
hail being the primary threat). Best chances for a severe
storm or two will be between 1-7 AM ET Thursday.
- Dry and cooler Friday and Saturday
- Very mild the first half of next week with increasing
rain/storm chances on Tuesday.
&&
.DISCUSSION...
Issued at 158 PM EST Wed Feb 21 2024
Clouds increase this evening ahead of the next weather system moving
in that will bring showers and storm overnight into the day
Thursday. A warm front lifts north through Missouri and Illinois
this evening, advecting warmth and moisture northward. Thunderstorms
should initiate in our forecast area after 06Z Thursday, mainly
along and south of the I-80/-90 corridor near the Indiana-Michigan
stateline. Convection should remain elevated, and thus the main
hazards will be heavy rain, lightning, and hail. I`d expect most
thunderstorms to produce sub-severe hail (less than 1", if they
produce any hail at all), but there is an isolated risk for a few
storms to produce severe hail (mainly quarter sized) in the 06-12Z
Thursday timeframe. Based on RAP soundings, the best chances for
isolated severe storms will be in west-central Indiana south of US
30 and west of IN-15. Additional showers and non-severe storms
persist through 15-18Z Thursday along and ahead of a cold front.
A dry, sunny, and seasonable weekend is ahead as high pressure
returns for several days! Temperatures dip briefly below normal for
about 24 hours from Friday evening to Saturday evening; Friday night
lows will be in the teens and Saturday`s highs only get into the low
30s. Any cold is short-lived, however, as temperatures will become
mild once again by Sunday and Monday.
Our next chance of rain/storms will be on Tuesday, although
confidence in storms is very low at this time. A warm front will
lift north Tuesday morning, with our forecast area potentially
in the warm sector during the afternoon Tuesday (depending on
how far north the front can get). As of now, our forecast has
highs in the mid 60s on Tuesday. This warmth, combined with several
hours of clearing, may present us with a high shear/low cape severe
setup Tuesday evening/early Wednesday morning as the attendant cold
front moves through. Again, confidence is very low in timing,
coverage, and intensity of any storms. This is just one of multiple
scenarios we are watching for Tuesday, as it is possible the best
warmth and moisture to fuel storms stays south of our forecast area.
Stay tuned for updates!
&&
.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 550 PM EST Wed Feb 21 2024
Rather sharp baroclinic zone aloft splits the terminals this
evening. Upstream jet streak and sw disturbance over KS will eject
rapidly e-ne overnight with pronounced backing aft midnight. Stream
of increasing theta-e aloft along with modest eml overspreading the
area will lead to abrupt shower/storm development 04-07Z of which
will affect the terminals for a time with induced MVFR conditions
extending through daybreak. Thereafter boundary and attendant
forcing for precip will shift south out of the area with rapid
following drying Thu aftn.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...None.
OH...None.
MI...None.
MARINE...None.
&&
$$
DISCUSSION...Johnson
AVIATION...T