Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 06/14/24
Area Forecast Discussion
National Weather Service Burlington VT
1007 PM EDT Thu Jun 13 2024
.SYNOPSIS...
A cold front moving through the Great Lakes this afternoon will
bring a period of showers and possibly thunderstorms to our region
late tonight into Friday with localized stronger storms possible in
far southern Vermont early Friday afternoon. Cool and dry air
filters in for the weekend, but by Monday, warm and moist air will
shift back into the region. Temperatures warming into the upper 80s
to mid 90s is expected by the middle of next week. In conjunction
with high dewpoints and warm overnight conditions, heat impacts are
likely next week.
&&
.NEAR TERM /THROUGH SATURDAY/...
As of 1003 PM EDT Thursday...A line of showers and thunderstorms
is rapidly approaching from the west. This line is expected to
move into the St. Lawrence Valley right around 11 PM, give or
take a few minutes, and will likely accelerate eastward as it
moves through the North Country. The latest TYX data shows a
50-60 knot jet art around 15,000 ft which should help push this
line eastward at a faster pace. The 00Z HRRR and RAP data
suggest we have decoupled with the loss of daytime heating which
should keep the stronger winds elevated since the convection
won`t be rooted at the surface. However, DCAPE values close to
800 J/kg exist so it`s still possible we could see a brief burst
of gusty winds along several portions of the approaching line.
All guidance has this line falling apart quickly through the
overnight hours but should be able to produce overnight rumbles
of thunder and brief heavy rain as it quickly moves eastward. We
will be watching the line closely should any warnings be
necessary although it currently looks unlikely.
Previous Discussion...The forecast remains on track for tonight
through Friday night with the main feature of interest being a cold
front currently moving through the Great Lakes region. CAMs have
been very consistent showing showers and embedded thunder associated
with the front won`t move into the St. Lawrence Valley until close
to midnight, then become fragmented and scattered as it moves
eastward through the remainder of the night into Friday morning.
With the loss of daytime heating and precip arrival time, along with
the best dynamics and cold pool shifting north of the region, the
threat for strong storms is low during the overnight hours despite a
strong low-level jet of 40-50kts moving across the region. As such,
gusty winds are likely the biggest threat which will continue up to
25 mph in the broader valleys overnight with the potential for brief
gusts greater than 35 mph along the frontal passage, mainly across
northern New York.
As the front shifts through Vermont during the daylight hours
Friday, a short window will exist in the early to mid-afternoon
hours for some stronger storms to develop across central and
southern zones where up to 1000 J/kg of CAPE and about 40-45 knots
of 0-6km shear may exist. As the previous forecaster mentioned, the
intensity of storms will be conditional on clearing, and SPC`s
depiction of a slight risk outlook south of our forecast area and a
marginal risk across Rutland and Windsor Counties of Vermont
continues to be reasonable. Any activity that does develop will wane
after sunset with the loss of surface heating and the front shifting
away from the region, and a quiet and cool night is on tap with lows
falling into the 40s and 50s.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY/...
As of 326 PM EDT Thursday...The weekend weather will be gorgeous,
featuring highs in the 60s and 70s, and low humidity. There will
also be abundant sunshine and relatively light winds. Clear skies
and calm winds overnight will allow temperatures to drop quickly.
Lows Saturday night will mostly be in the 40s, but temperatures
should reach the 30s in the coldest hollows. Enjoy the cooler
weather while it lasts because significant heat will build in next
week.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
As of 326 PM EDT Thursday...The first major heat event of the year
looks to occur next week, starting Tuesday and continuing for the
rest of the week. High temperatures above 90 degrees and increasing
humidity will likely cause apparent temperatures to be well in the
90s, particularly in the broad valleys. The region will be on the
northern periphery of an unusually strong ridge. Some model guidance
brings the center of it to 600 dm at 500 mb. Southwest flow will
prevent any cooling marine impacts from the Atlantic and increased
humidity will help lows stay elevated overnight. Temperatures in the
valleys will likely not fall out of the 70s Tuesday night onward,
preventing much overnight relief from the heat. While there is high
confidence of very warm temperatures, the exact magnitude of the
heat is still uncertain. It looks like there will be a couple of
shortwaves that will ride along the top of the ridge. With
sufficient instability from the airmass, it would not take much to
initiate some convection to keep afternoon temperatures a little
lower. Also, with westerly flow aloft from being on the northern
edge of the ridge, it is possible that debris from upstream
convection over the Great Lakes could stream into the area provide
some cloud cover. While this would limit high temperatures, it would
also increase overnight lows. However, despite these uncertainties,
there is high confidence in a significant heat event and the NBM
seems very reasonable in giving an 80-90 percent probability of
highs exceeding 90 in the broad valleys. However, the higher end
probabilities where it gives the Burlington area a 40-50 percent
chance of reaching 100 are likely unrealistic. Overall, this looks
to be a relatively long- duration significant heat event and it would
beneficial to take precautions early.
&&
.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
Through 00Z Saturday...VFR conditions are expected to continue
through about 09Z-10Z for most sites, with winds being the main
concern over the next 24 hours. Currently, wind across sites is
decreasing, but surface flow generally remains out of the south
3-9 knots. Winds will increase again tonight into tomorrow as a
cold front crosses the forecast area, bringing gusts to 10-30
knots at various sites. Winds will turn southwesterly and
eventually northwesterly by the end of the 24 hour period. By
around 18Z-22Z we may see another drop in the wind gusts. LLWS
is expected with the frontal passage, primarily 04Z-13Z.
As for ceilings and precipitation associated with the front, we
are not particularly concerned as models show the precipitation
weakening and falling apart as it crosses the forecast area.
Most likely chance of rain showers will be from 08Z-14Z, though
site MSS could experience a couple showers early, over the next
few hours. There is the potential for thunderstorms embedded in
any of these showers, but confidence is not high enough to
include any thunder in TAFs at this time. There is also the
potential for visibilities to drop in heavier showers/storms,
but again, ability to pinpoint when and wear this will occur is
not of high accuracy or confidence. Ceilings will likely drop to
MVFR at MSS and SLK, but as the front continues eastward,
ceilings are looking less likely to break VFR levels at all.
Outlook...
Friday Night: VFR. Slight chance SHRA.
Saturday: VFR. NO SIG WX.
Saturday Night: VFR. NO SIG WX.
Sunday: VFR. NO SIG WX.
Sunday Night: VFR. NO SIG WX.
Monday: VFR. NO SIG WX.
Monday Night: VFR. NO SIG WX.
Tuesday: VFR. NO SIG WX.
&&
.MARINE...
As of 326 PM EDT Thursday...A brief period of wind gusts up to
25 knots is expected across the broad lake waters tonight
prompting the issuance of a lake wind advisory. Waves will
likely build to 1 to 3 feet, and caution is urged for small
craft venturing out overnight.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.
&&
$$
SYNOPSIS...Lahiff
NEAR TERM...Clay/Lahiff
SHORT TERM...Myskowski
LONG TERM...Myskowski
AVIATION...Storm
MARINE...Lahiff
Area Forecast Discussion
National Weather Service Buffalo NY
1012 PM EDT Thu Jun 13 2024
.SYNOPSIS...
A cold front will slowly sag through the region tonight while likely
generating some showers and possible thunderstorms into Friday
morning. A fresh Canadian airmass and expansive high pressure in its
wake will guarantee fair but cool weather to start the weekend...and
this will be followed up by simply gorgeous weather on Sunday. Mid
summer heat and humidity will then build across our region for much
of next week with apparent temperatures in most areas soaring to
between 95 and 100.
&&
.NEAR TERM /UNTIL 6 PM FRIDAY EVENING/...
A fairly solid line of storms is rolling east across Quebec Canada
and the tail end of this convection is working across the
northern half of Lake Ontario. This area of storms will
`likely` reach Jefferson and the St. Lawrence Valley within the
next hour (03Z-04Z) or so. For Western NY...activity (just a few
spotty showers) along the advancing cold front is limited at
the moment. Will wait and see if any thing develops as the
front crosses Lake Erie. HRRR and other hi-res guidance isn`t
real bullish and is showing very little redevelopment. Have
lowered PoPs a bit given current trends and guidance.
Some leftover showers will be possible Friday morning...mainly south
of Buffalo, Rochester, and east of Watertown ...as the
aforementioned cold front will continue its slow push into
Pennsylvania. Clearing skies from north to south will then take
place during the midday and afternoon. This should leave pleasant
conditions for most areas for the latter portion of the day. It will
be cooler with max temperatures in the 70s.
Expansive high pressure over the Upper Great Lakes Friday evening
will slowly drift southeast during the course of the overnight. This
will guarantee fair dry weather with temperatures falling into the
50s.
&&
.SHORT TERM /6 PM FRIDAY EVENING THROUGH SUNDAY NIGHT/...
Broad mid-level ridging centered across the Central Plains Saturday
morning will shift east into the northern Great Lakes Sunday.
Meanwhile to the east, the mid-level trough centered over New York
State Saturday will give way to the Atlantic coastline. At the
surface, a broad area of high pressure will slide across the lower
Great Lakes supporting dry weather throughout the weekend.
With no real weather to speak of, the temperatures will be the focus
of the forecast for the foreseeable future. With the exiting trough
aloft, the last breath of cooler air will arrive for Saturday as
temperatures at 850mb dip down toward 7-8 degree Celsius. Highs
Saturday will range in the upper 60s to low 70s. As the ridge enters
the Great Lakes, temperatures aloft will begin to modulate
supporting highs to warm up into the low to mid 70s across the North
Country and the upper 70s to low 80s elsewhere.
Overall this weekend will be a great one to spend outdoors!
&&
.LONG TERM /MONDAY THROUGH WEDNESDAY/...
...Headline Worthy Summer Heat Expected This Period...
A prolonged period of heat and higher humidity will arrive next
week as a ridge of high pressure builds across the eastern
Great Lakes region. 500mb heights will climatologically be in
the 99th percentile for this time of year and even reach maximum
values for all hours over the Mid-Atlantic and southern New
England Wednesday through Thursday. A southerly flow will
transport a warm and moist airmass into the forecast area. Over
the course of the work week, the ridge will build north across
the eastern U.S. which opens the door for the potential for
"ridge riders" or clusters of thunderstorms to potentially
impact the region Monday through Tuesday. There is high
uncertainity that this will materilize but the pattern suggests
is a possibility. The ridge will then be centered overhead
Wednesday through Thursday which will lessen chances for
convective systems across the region.
Speaking on precipitation chances, dewpoints will climb to the upper
60s to low 70s through the work week. Surface based instability will
be on the rise during the day which may drive convection outside of
common lake shadows. There is a slightly higher chance of showers
and thunderstorms Monday afternoon and Tuesday afternoon than
Wednesday and Thursday.
In terms of sensible weather, this will translate to a prolonged
stretch of oppressive summer heat and humidity. Daytime temperatures
Monday will feature widespread upper 80s and lower 90s, though
remaining a bit cooler across the North Country with low and mid 80s
where a slightly cooler airmass will linger. By Tuesday and
Wednesday, widespread high temperatures in the low to mid 90s are
expected, hottest in the interior valleys and coolest just northeast
of both lakes (including the Buffalo area) as a persistent southwest
flow advects cooler marine air off the lakes. This heat comes as
dewpoints climb into the low 70s, which will cause overall heat
indicies in the afternoon to climb into the mid 90s to lower 100s.
Daytime highs average the upper 70s for Buffalo, Rochester, and
Watertown during the days of June 17-20.
It will not only be the impressive level of oppressive midday and
afternoon heat to contend with, but the cumulative impacts of only
having the mercury settle to near 70 for the overnights (Monday
night and beyond), thereby extremely limiting any relief.
&&
.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
VFR conditions will be in place through this evening. The only
potential issue will be gusty sfc winds up to 25 knots through
sunset...especially for the IAG Frontier (KIAG and KBUF).
A slow moving cold front will press through the region later tonight
and early Friday. While VFR flight rules are forecast to persist...
the front will support at least scattered shower and thunderstorm
activity. The exception will be across the Southern Tier where MVFR
to IFR cigs will be likely between about daybreak and midday Friday.
Outlook...
Friday night through Tuesday...VFR.
&&
.MARINE...
A cold front will move across the lower Great Lakes late tonight and
early Friday. Southwest winds will increase ahead of the front, with
winds remaining elevated through Friday. This will bring choppy
conditions to both lakes. High pressure will then build back across
the waters with light winds and generally favorable boating
conditions during the weekend.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...None.
MARINE...None.
&&
$$
SYNOPSIS...RSH
NEAR TERM...AR/RSH
SHORT TERM...EAJ
LONG TERM...HSK/PP/RSH
AVIATION...AR/RSH
MARINE...AR/RSH/TMA
Area Forecast Discussion
National Weather Service Columbia SC
822 PM EDT Thu Jun 13 2024
.SYNOPSIS...
Dry high pressure remains over the area again Friday. A weak
front moves in from the north Saturday, with a slight increase
in moisture. Mainly expect isolated afternoon convection to be
possible through the middle of next week. Hot temperatures are
expected throughout much of the forecast period.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
High pressure remains in place to our north. Clear skies and
overall dry conditions tonight, any fog should be limited to
near bodies of water. The clear skies will also allow
temperatures to be cooler than last night with forecast lows in
the mid to upper 60s.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
Friday will still be mostly dry as high pressure will continue
across the area. Weak stationary surface front well south does
extend northward and off the SC/GA coast, with low pressure
developing along it through the day. This low remains well
offshore and will be tracking away from the region. Moisture
across the area will remain limited, and a continued subsidence
inversion should limit any kind of rain activity to areas much
closer to the coast. Temperatures do reach into the middle 90s,
and heat index values will be similar due to the dry air in
place. Friday night will see a weak cold front moving towards
the area from the north, but once again the airmass ahead of the
front will be too dry for any rainfall to develop across our
area. Overnight lows generally in the lower 70s.
For Saturday, the front moves in and through, but really wont
see much impact for temperatures. Exception may be across the
very northern Midlands and Pee Dee where highs in the lower 90s
will be possible. Meanwhile elsewhere, guidance still generally
giving mid to upper 90s, with heat index values around 100
degrees. Continue to strongly encourage those that will be
outdoors to take frequent breaks and hydrate well. The subsidence
inversion will be weakening on Saturday however with dry air
expected to remain in the mid levels with light northerly to
northwesterly winds lending a bit of downsloping any potential
for convection would be in the eastern Midlands, and very
isolated at best.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
Much of the longer term period will see a strong upper ridge
across the region. At the surface, the center of an area of high
pressure off to our north will slowly be moving eastward off the
New England coast. This will eventually turn low level winds
more off the Atlantic, bringing an increase in moisture. Even
with the slightly better moisture, only expecting isolated
afternoon convection through the period due to the strength and
position of the upper ridge. Temperatures through the long term
will remain in the low to mid 90s with heat index readings
slightly higher each afternoon.
&&
.AVIATION /23Z THURSDAY THROUGH TUESDAY/...
VFR forecast.
High pressure across the area. Cumulus should dissipate soon
after 00z. Sky clear overnight with light and variable/near calm
winds. The NBM and HRRR guidance suggests VFR through the night.
There is a higher probability of stratus in the SC coastal Plain
overnight and expect the bulk of these clouds/or patchy fog to
remain to the southeast of OGB and AGS at this time. Scattered
cumulus will develop mid to late morning with cloud bases rising
to around 6000 Ft in the afternoon. Winds favor a north
direction less than 10 knots by 18z.
EXTENDED AVIATION OUTLOOK...Low probability of significant
restrictions although isolated to scattered afternoon showers
or thunderstorms possible Saturday and Sunday.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...None.
GA...None.
&&
$$
Area Forecast Discussion
National Weather Service Dodge City KS
752 PM CDT Thu Jun 13 2024
.KEY MESSAGES...
- Scattered severe thunderstorms are expected Thursday evening,
with strong outflow winds the primary threat.
- Another round of severe thunderstorms appears possible Friday
afternoon and evening as storms roll out of eastern CO.
- Multiple chances for precipitation exist through the long term
as upper level troughing takes hold over the western CONUS
this weekend through much of next week.
&&
.UPDATE...
Issued at 752 PM CDT Thu Jun 13 2024
Have begun the process of clearing the western zones from severe
thunderstorm watch #410. Strong MCS continues across the
southeast CWA at 750 pm, with radar/satellite imagery
indicating an uptick in intensity recently. Numerous reports of
wind gusts of 60-70 mph have been reported, along with
associated power/tree damage. MCS will clear KS by 9 pm,
followed by a quiet night. Winds will trend light and variable
through sunrise, with light easterly upslope. With the light
winds and more rainfall to add to the standing water across SW
KS, at least patchy radiation fog is likely near sunrise Friday.
&&
.DISCUSSION...
Issued at 200 PM CDT Thu Jun 13 2024
Midday water vapor satellite imagery and RAP upper air analysis
indicates a ~596-dm ridge is centered over the southern plains,
while the main belt of the subtropical jet is spread out over
the northern CONUS. At the surface, broad high pressure
extending from Dixie Alley into the central/southern plains is
resulting in southwest winds across our area, and these
downsloping winds along with mostly clear skies has supported
temperatures rising well into the 90s to low 100s. A weak cold
front associated with a low pressure system in eastern Canada
has recently crossed into northern KS, and will continue to sag
southward through the remainder of the afternoon. This boundary
will be the focus for some mid-afternoon thunderstorms across
southwest KS. With temperatures in the 90s/100s and dewpoints
mixing out into the upper 50s/low 60s, MLCAPE is expected to be
in the 1500-2500 J/Kg range. However, weak northwesterly 500-mb
flow will limit deep layer shear to 20-25 kts, which will act to
limit storm organization. That said, latest HREF does depict a
semi-organized linear convective system developing near KS-96
and moving south-southeast with time, along with some activity
moving out of southeast CO. The primary hazard with these storms
will be damaging wind gusts up to 70 mph, although some large
hail up to golf balls will be possible early in the convective
cycle. Thunderstorms will move into OK 08Z, and the rest of the
overnight period will be quiet as the cold front washes out
over our area.
Daytime Friday, short range ensembles agree a compact upper
level shortwave trough will move from the Desert Southwest
Friday morning to the central Rockies by Friday evening. 500-mb
height falls will support a slightly cooler afternoon, but
temperatures are still expected to peak in the 90s. As the
upper trough approaches, increasing forcing for ascent will
result in thunderstorms developing over the Rocky Mountains, and
move east into eastern CO. Eventually, these storms are progged
to move into western KS, but there is still considerable
uncertainty among HREF members regarding severity. Given
stronger winds aloft associated with the upper level impulse,
deep layer wind shear will be much more supportive of
organization, which would suggest storms will have no trouble
reaching western KS and posing a primarily severe wind gust
threat. This thinking is aligned with the latest Convective
Outlook from the Storm Prediction Center which places roughly
the northwestern half of our area in a Slight Risk (Level 2 of
5). Once again, thunderstorm activity will be clear of southwest
KS by sunrise Saturday morning.
Over the weekend and into next week, medium range ensembles
agree upper level longwave troughing will take shape over the
western CONUS. With slightly lower 500-mb heights and plenty of
southwesterly flow across the central Rockies, afternoon highs
will remain generally in the 90s along with multiple
opportunities for precipitation as both the ECMWF EPS and GEFS
show probability of QPF > 0.01" in the 30-60% range each day
through next Thursday.
&&
.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 450 PM CDT Thu Jun 13 2024
VFR and light winds will prevail through this TAF period,
outside of the influence of any convection. Radar at 2145z
showed scattered thunderstorms near LBL/GCK/HYS. Consensus of
short term models suggests at least a loosely organized complex
of thunderstorms through about 03z, with a primary risk of
thunderstorm outflow wind gusts in excess of 50 kts.
Thunderstorms are expected to be southeast of the airports by
06z Fri. Kept this set of TAFs simple with only VCTS/CB
mentions, but some TEMPO groups are possible if outflow
organization improves. VFR is expected Friday, with mid/high
clouds and increasing southeast winds.
.DDC WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 8 PM CDT this evening for KSZ066-081-090.
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 8 PM CDT this evening for KSZ066-081-090.
&&
$$
UPDATE...Turner
DISCUSSION...Springer
AVIATION...Turner
Area Forecast Discussion
National Weather Service Des Moines IA
626 PM CDT Thu Jun 13 2024
...Updated for the 00z Aviation Discussion...
.KEY MESSAGES...
- Severe storms with damaging wind gusts, large hail over
southern Iowa developing later this afternoon and moving out
of the state this evening
- Periodic shower and storm chances return later Friday night
through Sunday morning; locally heavy rainfall possible with a
low severe risk at this time
- Elevated heat and humidity Sunday into at least early next
week
&&
.DISCUSSION...
Issued at 148 PM CDT Thu Jun 13 2024
GOES-East Day Cloud Phase Distinction RGB has shown cumulus and
convective clouds along I-90 with most of the showers and the
handful of thunderstorms largely staying over far northern Iowa or
southern Minnesota. This activity was being forced by a weak
shortwave that is now moving through Minnesota. Our attention will
be on two surface boundaries that are over the state and which we
are monitoring this afternoon for convective initiation (CI). The
first is the surface front, which has pushed well into southern
Iowa. The second is a moisture discontinuity lagging behind a county
to two with dewpoints in the 50s behind it and well into the 60s to
low 70s ahead of it. This boundary may be the source for much of our
CI in the next few hours. Beyond the storms this afternoon, heat
south of this boundary has built with temperatures nearing 90
degrees and heat index a few degrees higher in the low 90s.
Latest SPC mesoanalysis shows mixed layer CAPE up to around 2000
to 2500 J/kg south of the moisture discontinuity boundary,
which is in line with latest HRRR model soundings. Forecast
storm inflow also points to wider updrafts and this along with
the thick CAPE profile and steep low and mid-level lapse rates
point to large (>1")to significantly (>2") large hail as storms
rapidly develop between 20z/3p and 21z/4p. While the hail risk
will remain as storms drift southeastward late this afternoon
and early this evening, damaging wind gusts potential will be on
the rise during this same time window. Convective allowing
models continue to point to severe (>58 mph) and possibly
significant (>75 mph) wind gusts over the southern two tiers or
so of Iowa counties along and east of Highway 169. The risk for
the significant wind gusts has been trending southward over the
last 18 hours or so and may end up more so over northern
Missouri, though we may still see some severe gusts over far
southern Iowa. While initial storms may have good stretching
for tornado potential, high LCLs, poor storm relative helicity,
and the lack of streamwiseness in soundings point to tornadoes
being unlikely.
The cold front will push south of the state early this evening with
the most sensible weather change being lower humidity and dewpoint
values back into the 50s on Friday. Highs on Friday will be similar
over northern Iowa, but at least several degrees lower over southern
Iowa. Moving into the forecast this weekend, GOES-East upper level
water vapor imagery shows a closed low nearing the California coast
today. This low will open up and move northeastward toward Iowa
bringing a lead wave Friday night into Saturday with the main
shortwave arriving Saturday night into Sunday morning. Both of these
will bring chances for thunderstorms. While instability will build,
shear is looking more marginal for anything more than a low severe
risk. Heavy rainfall parameters may be the more impressive part with
precipitable water values topping 2 inches from western Iowa arcing
up into parts of northern Iowa Saturday afternoon into Saturday
night with deep warm cloud depths. Latest NBM paints probabilities
of greater than 2 inches of rainfall in a 24 hour period over
northwest Iowa between 15 to 30%. This is also where the latest
ECMWF extreme forecast index has 50-70% of its members with an
anomalous event with a shift of tail of zero over the Siouxland area.
Much of the rainfall will be moving east of the state by Sunday
afternoon as the main shortwave moves into the Great Lakes. At the
same time, a ridge will build over the eastern US with the high
centered over the central Appalachians while a longwave trough sets
up over the western US. With Iowa between these two, the question
becomes whether the ridge`s influence will be sufficient to keep
shortwaves moving through this flow far enough away to limit storm
chances with more elevated heat conditions. Or, does the trough
impinge more on the state with higher storm chances and heat
mitigated either in magnitude, time, and/or area? Ensemble data
points to the ridge being the favored outcome early next week with
the GEFS mean being the detractor and bringing slightly higher PoPs
into the state. With the ridge favored, this would point to heat
being the larger story vs storms. At this time, the experimental
HeatRisk is pinging both Monday and Tuesday with a level 4 of
4/extreme over portions of eastern into central Iowa. While daytime
heat index values near 100 degrees these days, the HeatRisk is
likely keying on the anomalous overnight lows, which are in the
middle 70s over this area. All this to say that for central Iowa
this will be the first multi-day heat episode and at least those who
are more sensitive or susceptible to heat should take
precautions.
&&
.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 619 PM CDT Thu Jun 13 2024
VFR conditions will prevail through the period. Showers and
thunderstorms from the afternoon will continue to clear out of
the area, and not expecting any further impacts to terminals at
this time. Light winds and clearing skies are expected
overnight into tomorrow.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
DISCUSSION...Ansorge
AVIATION...Dodson
Area Forecast Discussion
National Weather Service Goodland KS
722 PM MDT Thu Jun 13 2024
.KEY MESSAGES...
- Severe weather is possible over much of the area on Friday.
Storms will develop in Colorado during the afternoon and move
eastward through the remainder of the area Friday evening into
Friday night. Some of these storms will be capable of
producing large hail and damaging winds. Locally heavy
rainfall and isolated flash flooding are also possible.
- Return of triple digit heat expected on Sunday.
&&
.UPDATE...
Issued at 700 PM MDT Thu Jun 13 2024
As of 0100 UTC, convection has since progressed ESE-SE into
central and southern Kansas. Regional mesoanalysis data
indicates a considerable amount (200-300 J/kg) of convective
inhibition is already present over the Goodland CWA.. and that
CIN will further increase with loss of heating AOA sunset.
Additional development is not anticipated. Severe Thunderstorm
Watch 410 was cancelled at 621 PM MDT / 0021 UTC.
&&
.SHORT TERM /THROUGH FRIDAY NIGHT/...
Issued at 122 PM MDT Thu Jun 13 2024
Across the Tri State region this afternoon, skies are sunny for
most except for clouds developing along a front near the I-70
corridor from Highway 27 and points west. Temperatures as of 100
PM MDT are ranging from the mid 90s into the lower and mid
100s. Winds are northeasterly gusting to 20-25 mph at times.
The main wx concerns in the short term period will be the threat for
strong to severe storms during the afternoon/evening hours today and
again on Friday.
For the remainder of the afternoon into tonight, the focus for
convective initiation will be along the frontal boundary which
currently sits along/south of I-70. Some cumulus is popping up and
will be monitored through the afternoon. Parameters suggesting even
some landspouts are also possible initially as storms move along the
front. The latest CAMs are showing convection beginning in earnest
around sunset and continuing into the evening hrs. With a very dry
airmass, soundings are showing strong DCape values around 00z Friday
in the 2200-2400 j/kg range and SBCape/MUCape in the 1800-1900j/kg
range.
Looking for main threats as large hail and damaging winds. SPC has
upgraded the CWA to a Slight Risk for severe, with wind/hail
threats. Can`t rule out an isolated tornado as well. The NamNest,
HRRR and RAP all show most of the activity moving east this evening,
with the bulk south of I-70 and the front. Some lingering rw/trw is
possible through 12z Friday, but pops will be in the 30-40% range
tapering to 15-20% overnight.
Going into Friday/Friday night, the region again blanketed under a
Slight Risk for storms, for the afternoon and evening hours.
Guidance is showing the upper ridge currently over the southern
Rockies to shift east into the southern Plains. This will allow for
a couple shortwaves to work into the CWA along the northern
periphery of the upper ridge. The one set to interact with a strong
surface trough during the evening hours, will create the best
chances for severe storms. Wind and hail are main threats, along
with an isolated tornado, especially north of I-70. Soundings
suggest large hail of at least 1-2 inches are possible, with some
2+. PW values of 1-2 inches will also result in the threat for
locally heavy rainfall creating flash flooding concerns. Convection
shifts/clears west to east overnight as both the surface/upper
features clear the CWA towards 12z Saturday. Best chances after 06z
will be east of Highway 25, but the bulk of highest pops 70-80% will
be during the evening hours.
For temps, the region will see daytime highs on Friday range in the
mid to upper 80s. This will be offset by lows tonight ranging in the
lower to mid 60s, and lows Friday night ranging from the lower 60s
west into the mid and upper 60s east of Highway 25.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
Issued at 1221 PM MDT Thu Jun 13 2024
Saturday we will see the leftovers over the upper-level low move
through and out of the area. This could sparks up some showers and
lower end storms. The greatest potential hazard would be if this
precipitation moved over areas that had been rained on the previous
couple of day, creating a flooding risk.
Sunday, the low will clear the area and we will be under weak
southwesterly flow aloft. This will give us about a 15-20% daily
chance of precipitation due to shortwaves in the evenings, but
nothing highly organized is expected until the weak flow is
disrupted, likely Tuesday afternoon. Around this time, the pressure
gradient tightens up as the low over the NW CONUS pushes farther
inland. This would work to amplify any disturbances and increase
chances for PoPs. By mid-next week, we could see the low moving into
the Great Plains and sending a cold front through the region. This
would spark up some storms and start cooling temperatures down some.
High temperatures until mid-next week look to be in the low 90s to
low 100s. After the cold front moves through, after Tuesday, we will
likely only warm into the 80s and low 90s. Overnight temperatures
will follow a similar pattern and drop into the 60s to low 70s each
night, save for Sunday night. Sunday night, additional cloud cover
and fairly strong winds from the south are expected to keep
temperatures in the mid 60s to mid 70s. Gusts overnight could get up
to 30 kts. Behind the cold front, lows will cool down into the mid
50s to low 60s.
&&
.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 600 PM MDT Thu Jun 13 2024
GLD: Aside from a potential for MVFR-IFR ceilings a few hours on
either side of sunrise Friday morning.. and a potential for
thunderstorms Friday evening (00-06Z Sat).. VFR conditions will
otherwise prevail. NE winds at 10-17 knots this evening will
veer to the E (overnight) and SE (Friday).
MCK: Aside from a potential for thunderstorms Friday evening
(00-06Z Sat).. VFR conditions will prevail. NE winds at 10-17
knots this evening will veer to the E (overnight) and SE
(Friday).
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...None.
CO...None.
NE...None.
&&
$$
UPDATE...Vincent
SHORT TERM...JN
LONG TERM...CA
AVIATION...Vincent
Area Forecast Discussion
National Weather Service North Platte NE
659 PM CDT Thu Jun 13 2024
.KEY MESSAGES...
- Recurring chances for rain and thunderstorms are likely with strong
to severe thunderstorms possible Friday and Saturday.
- Some uncertainty remains but more severe weather is possible
on Sunday.
- Fairly active pattern continues into next week but confidence
in temperatures is low at this time.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 346 PM CDT Thu Jun 13 2024
Mid-afternoon surface analysis depicts much of the area in general
east-northeasterly flow behind a cool front that passed early this
morning. This helped bring a swift end to the heat that was observed
Wednesday and the quick progression with cooler air filtering in
behind has held afternoon highs into the low 80s with locations
south of Interstate 80 still managing near 90 degF.
Surface high pressure will shift east across the Red River Valley of
the north. Low-level fetch will originate from this source through
late today which is supportive of the cooler temperatures. Flow will
continue to veer to easterly by late afternoon which will help drive
the formating of rain and thunderstorms off the Front Range to the
west. With the effective front well to the south, the bulk of any
instability will be removed to the south and this is where the Storm
Prediction Center (SPC) has placed their latest Day 1 Marginal Risk
(level 1 of 5). This outlook clips our far southwest corner but
confidence in seeing a notable thunderstorm potential, much
less severe threat, is low. HREF probabilities are quite low
with ensemble max QPF output showing less than 0.10" anywhere in
our forecast area. This is likely due to the fact that the
local environment is fairly hostile to convection with
significant capping thanks in part to h85 and h7 temperatures in
the low 20s and middle teens degC respectively. As temperatures
cool this evening, low-level capping will only increase which
should help keep most if not all locations dry. Lows tonight
should fall into the upper 50s to low 60s.
&&
.LONG TERM /FRIDAY THROUGH THURSDAY/...
Issued at 346 PM CDT Thu Jun 13 2024
Friday and Saturday...likely the more noteworthy period of time in
the forecast period. Upper-level ridge of high pressure to the south
will slowly shift east with upper ridge axis approaching western
Nebraska by early Friday morning. A disturbance will track into the
Desert Southwest and carve its way through the ridge aloft. This
will prompt ridge breakdown during the day Friday. Southerly flow
will enhance ahead of this feature as low pressure begins to develop
across central Wyoming. This stronger flow will help usher in richer
boundary layer moisture as dew point values quickly recover back
into the 60s. Combined with modest lapse rates aloft, moderate to
strong instability will develop as MLCAPE values are progged to
climb into the 1500-2500 j/kg range by 00z Saturday (7pm CDT Friday)
as afternoon highs reach the low to middle 80s. Under a localized
speed maximum, deep layer shear will be supportive of organized
convection with 0-6km BWD values in the 25 to 35 knot range. This
should support multicell storm modes with a few embedded supercells
possible. Forcing for ascent will quickly ramp up by evening as the
main PV anomaly crosses the Central Rockies. Subsequent height falls
will peak Friday evening into Saturday morning. By early to mid-
evening, expectations are for thunderstorms to quickly track north
and east out of Colorado/northwest Kansas and into southwest
Nebraska. Primary concern will be damaging wind gusts as hi-res
guidance indicates a fairly quick upscale progression of
thunderstorms into an environment with moderate DCAPE (800-1200
j/kg) and delta theta-e differentials of greater than 25 degC.
Extended HRRR guidance (12z and 18z runs) shows areas of enhanced
wind gusts exceeding 40 knots and even peaking around 60 knots.
While large hail will also be possible, this will primarily reside
in storms that can remain discrete which will be a decreasing
probability as the evening progresses. Though a tornado cannot be
ruled out given modest curvature in the lowest levels, confidence in
seeing one is quite low given storm mode and quickly invading cold
pool conglomeration. The latest SPC Outlook for Friday has much
of the area in a Slight Risk (level 2 of 5), and generally have
no qualms with this. Precipitation will persist overnight into
Saturday with PoPs peaking around Midnight CDT Friday night
around 80%. Forcing wanes as the trough axis clears the local
area around sunrise Saturday and as such have PoPs quickly
decreasing from west to east through the morning Saturday.
Uncertainty exists around how the afternoon hours Saturday play
out. With clouds and precipitation chances potentially lasting
into the early afternoon, environmental recovery is somewhat
uncertain. The latest SPC Outlook for Saturday show our far
north central zones in a Marginal Risk (level 1 of 5) and
believe this is adequate for now given some lingering
uncertainties. It`s interesting to note that the operational NAM
and GFS keep any afternoon redevelopment east of the forecast
area so we`ll need to monitor for increasing/decreasing
probabilities. Depending on pace of clearing, temperatures
remain somewhat uncertain though forecast highs are likely to
return to above normal values reaching the middle 80s east to
low 90s west.
Sunday...an interesting day with a clash of cooler and more mild
airmasses across the central Plains. Behind the departing trough, a
fairly progressive cool front will dive south along the lee of the
northern Rockies. Further south, southerly flow will reinforce low-
level moisture with dew points likely to remain in the lower 60s.
Eventually, the cool front will win out with moderate CAA
overspreading the area. How far south this front reaches is the
subject of greatest uncertainty as temperatures remains more mild to
the north and hot to the south. Eventually, this frontal boundary
will still and lift back north slightly as a warm front. Easterly
upslope flow immediately north of the surface boundary will support
orographic lift across northeast Colorado while the front itself
will be a possible focus for thunderstorm development. NWP guidance
varies quite widely about placement of this boundary and thus where
greatest PoPs set up. For now, believe inherited Chance PoPs (up to
50%) are adequate though subsequent forecasts could introduce large
changes to these values. The NAM is furthest south with this frontal
boundary whereas the GFS/ECWMF shows it settling around the I-80
corridor. Capping will be strong but strong forcing from low-level
convergence may be enough to overcome this especially as the evening
low-level jet ramps up. Strong instability and deep layer shear will
be in place and suggest an organized severe weather event but
confidence in realizing thunderstorm initiation is low. Will need to
closely monitor this potential in the coming days.
Monday and beyond...continued southwesterly flow with a steady
parade of northern stream disturbances should keep the extended
forecast on the active side next week. While day-to-day
predictability will remain low given model guidance variations,
recurring afternoon and evening thunderstorm potential appears at
least probable for the foreseeable future. Persistent fetch
from the Gulf of Mexico should provide adequate moisture to
support this idea. NBM guidance for temperatures next week show
large spread in 25th to 75th percentile values and this is
likely due to some uncertainty on how far east the upper-level
troughing encroaches on the area. For now, deterministic
solutions show daytime highs remaining in the 80s for most but
large swings are possible as confidence in evolution of the
extended becomes more certain.
&&
.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 659 PM CDT Thu Jun 13 2024
VFR conditions will prevail across western and north central
Nebraska through the period. Scattered showers and a few
thunderstorms are possible Friday after 12Z. Have included a
mention at KLBF from 14Z through 00Z/14th. Confidence however
is low on specific impacts to either terminal site at this time.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...NMJ
LONG TERM...NMJ
AVIATION...Roberg
Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
651 PM CDT Thu Jun 13 2024
.KEY MESSAGES...
- Thunderstorms are expected across parts of northern Missouri and west-
central Illinois this evening, and a few of these storms are
likely to be capable of producing damaging wind and large hail.
A tornado cannot be ruled out. Storms may reach the I-70
corridor, but confidence is low that they will remain severe
this far south.
- Above average temperatures will persist through the middle of
next week and will most likely peak Sunday and Monday. Afternoon
temperatures in the mid to upper 90s will be possible those days
with lows falling into the 70s.
&&
.SHORT TERM... (Through Late Friday Night)
Issued at 257 PM CDT Thu Jun 13 2024
The primary concern in the short term remains the potential for
severe thunderstorms across parts of the area between late this
afternoon and evening, which will develop along a slowly advancing
cold front. Ahead of this front, temperatures have quickly soared
into the upper 80s to low 90s, thanks to a stout ridge that has
built across the central CONUS and southwesterly low level flow.
Meanwhile, pooling moisture along and south of the front has also
kept surface dewpoints in the low 70s, resulting in heat index
values already well into the mid 90s to near 100 in some places.
Temperatures will continue to climb another degree or two through
the remainder of the afternoon, and heat index values should reach
somewhere between 95 and 105 in most areas. This is well above
average for this time of year, but remains short of values that
typically cause widespread heat impacts.
This ample heating has also contributed to the buildup of
significant instability, with RUC mesoanalysis indicating values of
2000-3000 J/kg of MLCAPE along and south of the advancing boundary
in northern Missouri and west-central Illinois. This aligns well
with a special 18Z sounding in the Quad Cities, which observed
around 2000 J/kg of MLCAPE. These values will continue to increase
through the afternoon, and while there remains significant CIN due
to a mid-level warm nose (also evident in the 18Z DVN sounding), it
is expected that this will erode sufficiently for convective
initiation later this afternoon.
Storms are expected to develop along the boundary initially near the
IA/MO border, and slowly move southeastward. Considering that
mid/upper forcing from a passing shortwave to the north is weak,
initial storms are likely to be discrete as storms fight through the
remaining CIN. Shear profiles and slightly clock-wise turning to
straight line hodographs also support supercells, although
relatively modest low level winds and shear may be a limiting
factor, particularly for tornadoes. These initial storms will be
capable of producing large hail, with some significant hail possible
as well, although it remains to be seen if these storms will remain
discrete as they move south and into our forecast area.
As time progresses, there is conflicting data regarding whether
storms will remain discrete, or merge into one or more line
segments. Northwesterly 0-6km shear vectors do have a significant
orthogonal component to the initiating boundary, and the lack of
strong forcing also supports the continuation of discrete modes.
However, CAM output has fairly consistently depicted upscale
growth into linear modes, albeit with some timing variability, and
this potential increases as storms move farther and farther
south. The potential for damaging wind also increases as storms
assume a more linear mode, which will also be supported by steep
low level lapse rates and some mid level dry air entrainment
(DCAPE 1000-1300 J/kg). As for tornadoes, weakness in low level
flow significantly limits available low level shear, with 0-3km
shear reaching only 20 to 30kt, and 0-1km shear only around 20 kt.
This is maximized in the evening as a modest low level jet ramps
up, but even then, veered low level winds are also not favorable.
Still, considering the strong instability at all levels, the
presence of surface boundary, and just enough ambient shear, we
can`t rule out a tornado or two.
Storms are likely to be at their strongest across northern Missouri
and west-central Illinois, roughly along and north of the Hwy 36/Hwy-
72 corridor between around 7 and 9pm. Confidence in their strength
decreases as we progress later into the night as instability wanes
and storms outrun the forcing and initiating boundary. There is at
least some potential for storms to remain severe as they reach the I-
70 corridor later in the evening, but confidence remains low that
this will occur.
Overnight, the cold front will slowly advance southwards, but trends
in latest model guidance have slowed this front to the point where
it is unlikely to clear the forecast area, perhaps stalling as far
north as I-70. This would allow for the buildup of instability again
tomorrow afternoon, albeit with strong convective inhibition and
even weaker forcing/wind shear. As such, we can`t rule out a
smattering of primarily weak thunderstorms during the late afternoon
tomorrow, primarily south of I-70. Meanwhile, temperatures north of
the front will settle back into the mid to upper 80s, and likely
reach into the low 90s along and south of it.
BRC
&&
.LONG TERM... (Saturday through Next Thursday)
Issued at 257 PM CDT Thu Jun 13 2024
Long Term:
A mid-level ridge currently centered over New Mexico and western
Texas will deamplify and spread eastward over the remainder of the
work week, even as it deepens. By the weekend the ridge will
encompass the entire southern CONUS, while a shortwave trough will
propagate through the westerlies just to the north. This
shortwave will slide through the mid-Mississippi Valley Saturday
night, but the best chances for precipitation over the weekend
will be to our west where better surface convergence will be. Deep
southwesterly flow will establish in the wake of the shortwave,
and kick off a warming trend that has the potential to last
through the end of the forecast period.
850mb temperatures during the end of the weekend and start of the
work week are forecast around 20C, which under full sunshine and
after several days of highs already in the 90s pushes high
temperatures into the mid 90s. How high exactly we warm remains
uncertain and dependent upon cloud cover and additional rain
chances. Despite this, the NBM interquartile spread is less than 5
degrees and well above normal, thus confidence is high we`ll see
the first hot spell of the season this weekend and into at least
the first portion of next week.
While the mid-level ridge shifts over the mid-Atlantic by mid week,
the mid-Mississippi Valley remains in deep southwesterly flow,
increasing confidence that hot temperatures will stick around. While
southwesterly mid-level flow does leave the region open to
disturbances and precipitation chances, there`s not yet a strong
signal on when the next chance for precipitation will be.
MRM
&&
.AVIATION... (For the 00z TAFs through 00z Friday Evening)
Issued at 638 PM CDT Thu Jun 13 2024
Strong to severe thunderstorms threatening 50-60kt wind and large
hail will continue to threaten mainly KUIN over the next few hours
along and just ahead of a slow-moving cold front. The activity
will slowly sag south with time and threaten the remaining TAF
sites, however the potential for convection directly impacting
any one site is still uncertain. If these storms grow into a
well-defined line, there will be a threat for prevailing thunder
at all terminals. Following the thunderstorms overnight and a cold
front passage, dry VFR conditions will prevail through the
remainder of the TAF period.
MRB
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&
$$
WFO LSX
Area Forecast Discussion
National Weather Service Morristown TN
915 PM EDT Thu Jun 13 2024
...New UPDATE...
.UPDATE...
Issued at 908 PM EDT Thu Jun 13 2024
Shower activity was less than expected this afternoon. CAMs have
dry weather continuing through the overnight period. No
changes were made to the forecast for tonight during the evening
update.
&&
.SHORT TERM...
(This evening through Friday)
Issued at 254 PM EDT Thu Jun 13 2024
Key Messages:
1. Hotter weather tomorrow. Very low chance at a shower or
thunderstorm.
Discussion:
Summer weather to continue. Scattered cu fields of variable
thickness exist across the wider region, with more consistent
coverage over the mountains. Only question this afternoon is if any
shower or thunderstorm can fire. The HRRR has a midlevel inversion
around 3km, whereas the NAM has a slightly more favorable profile
that would allow for convection. 12z HREF paints a consistent
showing for a thunderstorm or two over the mountains. It`s not
impossible for a brief storm over the Plateau, but it`s not
expected.
The upper level ridge dominating our weather is currently anchored
over the southern Plains, and will slowly move east with time. The
588dm line will move over the Chattanooga metro tomorrow. This
corresponds to roughly the 90th percentile for 500 mb heights off
the Nashville sounding climatology. Accordingly thanks to the
building heights, tomorrow will be slightly warmer than today was,
with some locations in the southern valley entering the low 90s. GFS
and HRRR have some convection riding the ridge axis tomorrow coming
from the midwest but collapsing before entering this area. HREF
brings a slight 20% chance for additional northwest flow storms
tomorrow afternoon. No significant weather is expected.
&&
.LONG TERM...
(Friday night through next Thursday)
Issued at 254 PM EDT Thu Jun 13 2024
Key Messages:
1. Above normal temperatures through the period, and right now the
hottest days look like Sunday and perhaps Monday.
2. Mostly dry overall, but a few spots especially over the higher
terrain will see a shower or thunderstorm with the highest coverage
potential expected to occur Monday.
Discussion:
We start the period with an upper ridge centered to our west, and a
large area of surface high pressure extending into our area from the
northwest. The upper ridge will build east and will set up
residence over the eastern U.S. where it will remain for the
remainder of the period. Meanwhile, the surface high will slide east
and will continue to extend into our area but will be centered off
the the East Coast by early in the week. In this pattern, we will
see mostly dry conditions as organized convection will be unlikely
under the upper ridge. However, there may be some mainly isolated
and diurnally driven convection especially over the higher terrain.
Most model solutions show a bit more moisture available on Monday,
so the coverage is expected to tick higher Monday afternoon and
there may be isolated showers or storms even over valley locations.
Temperatures will run above normal for the entire period, with the
heat likely peaking Sunday and possibly again Monday as the
combination of higher dew points and well above normal temperatures
are expected to result in heat index values reaching to around 100
across portions of the central and southern valley. The flow will
turn more easterly for the latter periods as the highest heights
shift to the northeast, which should result in slightly lower
temperatures, although highs will still be significantly above
normal for Tuesday through Thursday.
&&
.AVIATION...
(00Z TAFS)
Issued at 715 PM EDT Thu Jun 13 2024
VFR conditions continue this forecast cycle. Winds will be light
and westerly. Low rain chances tomorrow afternoon are mainly
confined to NE Tennessee and SW Virginia.
&&
.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN 69 94 72 93 / 0 10 0 0
Knoxville McGhee Tyson Airport, TN 66 91 69 90 / 0 10 10 0
Oak Ridge, TN 66 91 68 90 / 0 10 0 0
Tri Cities Airport, TN 63 86 65 86 / 0 20 10 0
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
SHORT TERM...Wellington
AVIATION...McD
Area Forecast Discussion
National Weather Service Topeka KS
539 PM CDT Thu Jun 13 2024
.KEY MESSAGES...
- Hot and humid Today with afternoon heat indices of 101-110
degrees. A Heat Advisory in effect from noon-8pm today.
- Isolated to scattered storms late this afternoon into the evening.
These storms could be severe with large hail and damaging wind
gusts being the main hazards.
- Above-normal temperatures continue into early next week.
&&
.MESOSCALE...
Issued at 539 PM CDT Thu Jun 13 2024
Convection has begun along the frontal boundary in north
central KS, but has been slow to intensify to severe levels.
Regardless, MLCAPE values from the 20Z RAOB over 4000 J/kg and
0-6km shear near 40KT support the potential for supercell storms
with large hail. The last couple runs of the HRRR have shown
that these storms may be capable of wind gusts over 80 MPH as
well. Still some modest MLCIN and marginal shear across central
KS may be the reason for the gradual build up in intensity. The
window for severe storms looks to be through 10 or 11 pm
tonight.
&&
.DISCUSSION...
Issued at 340 PM CDT Thu Jun 13 2024
Summer is in full swing across northeast KS this afternoon as
temperatures have soared into the mid to upper 90s, some seeing the
year`s first triple digit temperatures! Along with heat, persistent
southerly low-level flow has advected in a wide area of low to mid
70 degree dewpoints making it feel much hotter than air
temperatures. A heat advisory continues this afternoon across the
whole warning area for heat indices ranging from 100-110 degrees.
This pooled moisture has been in response to a deepening trough axis
and associated surface boundary moving southeast out of southern
Nebraska that will later become the focal point for convection, and
possibly a few severe storms. Taking a look at current convective
parameters show a capped warm sector ahead of the frontal boundary
that is currently positioned from west-central Kansas through
southeastern Iowa. Above the well-mixed BL, MLCAPE shows values
approaching 4500 J/kg in far northeastern Kansas where moisture
pooling has seemed to maximize ahead of the boundary. 0-6km shear
remains marginal, between 30-40 knots with the higher values hugging
the KS/NE border. As the frontal boundary continues to slide further
south into northeast KS, ML capping should slowly erode a bit with
RAP analysis having MLCIN around 20 J/kg just ahead of the boundary
by 7 PM today. Although convergence along this frontal boundary does
not appear overly strong, a few to scattered storms should develop
between 6-8 PM this evening and given the aforementioned
environmental parameters, storms will quickly become strong, and
possibly severe. That said, this severe set up seems highly
conditional for a few reasons and comes with some uncertainties...
first, storms may struggle to overcome the afternoon capping
inversion and not maintain themselves long enough to become
organized...second, if storms can develop, as they move southeast
into a less shear-dominated region, outflow boundaries may outrun
convection and spark up other convection away from the front. CAMs
(mainly the HRRR) have produces several runs of post-frontal
convection along and north of I-70 later this evening from storms
moving out of central KS. If these can persist, they will have ample
amounts of elevated instability to tap into, but will remain very
elevated. Cannot rule out an isolated wind gust if some of this
convection can cool the inversion a bit, but large hail (around
quarter-sized) will be the main threat.
By midnight tonight, convection will have mostly dissipated or moved
out of the area as the low-level boundary sags into southeastern KS.
The next chance for storms should hold off for most of the day
Friday as a large upper low moves out of NM, deepening a surface low
over the lee of the Rockies during the day. The best forcing remains
west of the area as isentropic surfaces and low-level flow keep the
best lift going upslope towards the surface low in Colorado.
Convection initiated near the mid-level vorticity max and surface
low during the day Friday will slowly push east during the day,
congealing into a complex of storms as it approaches central and
north-central KS. A few storms within this complex Friday night into
Saturday morning could be strong to severe with large hail up to
quarters and damaging winds to 60 mph.
The slow-moving upper-low hangs out into Saturday as the bit of
vorticity rounds the last axis of the trough. Thunderstorms will
again be possible during the afternoon and evening across central
and north-central KS with the enhancement of upper level support.
Shear and instability on Saturday across the area is out of
alignment for a widespread severe event with no obvious areas of
forced ascent within the warm sector, so confidence remains low in
most areas seeing strong any storms during the day. Highest
confidence remains mainly north of the area where better moisture
and instability reside. Because of the lack of confidence, did not
deviate much from NBM PoPs of 30%. Temperatures for the weekend and
early next week will get into the low to mid 90s, remaining fairly
muggy with low chances for rain.
&&
.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 539 PM CDT Thu Jun 13 2024
Trying to determine whether convection impacts the terminals
with the effective boundary still north of them. The last few
runs of the HRRR suggest at least a tempo for TS is warranted
until 02Z or 03Z. Outside of the convection, VFR conditions are
forecast to prevail into Friday.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 8 PM CDT this evening for KSZ008-KSZ009-
KSZ010-KSZ011-KSZ012-KSZ020-KSZ021-KSZ022-KSZ023-KSZ024-KSZ026-
KSZ034-KSZ035-KSZ036-KSZ037-KSZ038-KSZ039-KSZ040-KSZ054-KSZ055-
KSZ056-KSZ058-KSZ059.
&&
$$
MESOSCALE...Wolters
DISCUSSION...Griesemer
AVIATION...Wolters