Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/16/24
Area Forecast Discussion
National Weather Service La Crosse WI
1056 PM CDT Mon Jul 15 2024
.KEY MESSAGES...
- Scattered to areas of storms from late afternoon into early
evening. Some will be strong to severe with a damaging wind and hail
threat.
- Turning cooler and less humid for the rest of the week while also
trending dry.
&&
.DISCUSSION...
Issued at 200 PM CDT Mon Jul 15 2024
* STORM CHANCES THIS AFTERNOON/TONIGHT - some strong to severe
possible from late afternoon into early evening
CLouds and showers persisting for the early afternoon, tracking west
to east across southern MN through central WI - working to keep the
local environment relatively stable. Just south of there more sun has
been working on the juicy airmass over IA with the RAP suggesting
3500+ SBCAPE possible over northeast IA by 21z. Bit of shortwave
energy coupled with approaching sfc low and left over outflow
boundary will look to fire convection by mid/late afternoon - but
stout low level cap (per RAP/HRRR bufkit soundings) will keep a lid
on activity before those move in. This could hold off initiation
until after 4 pm. Mostly straight line hodograph in the RAP/HRRR
with 0-6km shear around 40 kts supporting convective updrafts and
some supercellular potential at outset. System could quickly morph
into a convective complex capable of swaths of damaging winds - but
more likely southeast of the local area. Ongoing clouds/showers
provide uncertainty as to northward extent of this particular area
of convection, and this region could change by the hour based on how
the afternoon unfolds. Some HRRR runs keep any significant
convection south/east of the local area. Currently, local severe
threat looks highest for northeast IA and southwest WI in the 4 to 7
pm time frame.
To the north, a cold front with another piece of upper level energy
will be slide cross northern portions of WI. Some clearing there
will increase instability and CAMS models trigger a broken line of
convection (tied to the front) that would drop southeast across the
forecast area. More multicellular with a mixed big of strong/severe
potential outcomes (hail, strong winds). Severe threat is lower with
these storms compared to the anticipated convection over IA.
All the storms would have the potential for locally heavy rain, but
all look to be moving at a good clip with no training of note via
the CAMS. Localized flooding issues could arise, but don`t see a
widespread heavy rain/flooding threat that would warrant a Flood
Watch at this time.
* TUESDAY INTO THE WEEKEND - cooler and less humid, trending dry
Another lobe of upper level energy slated to rotate across the upper
mississippi river valley Tue afternoon/evening. Cold air advection a
loft will promote a ribbon of increased low level lapse rates with
perhaps 250-500 J/Kg of MUCAPE. Questions on whether there will be
enough saturation to play with results in mixed signals in the
various short term models (some produce spotty to scattered late
afternoon shower/storms...others don`t). With a bit more support for
at least a smattering of light showers, will paint in some low pops
(20%) for the afternoon in a west-east running band, sliding
southward across the region and mostly south of the area by 00z.
Upper level blocking pattern then taking shape for the rest of the
week as ridge continues to amplify/hold firm across the rockies/west
coast while a trough holds over the new england states.
Much cooler and less humid air will flow in from Canada and set up
shop through the upcoming weekend, and could linger well into the
following week. EPS and GEFS members only show a few degree spread
between their 25-75% for highs - mostly topping out in the 70s
through Fri. Probabilities in the LREF start to push to 40-50% to
climb back into the 80s moving into the weekend, but certainly
nothing trending hot & humid.
Meanwhile, the current upper level layout would generally keep most
of the shortwave activity either into Canada or off to the west.
While can`t completely rule out some small rain chances here and
there, it`s looking like a dry spate of days for most of the region
through the weekend. A welcome break from the recent soggy
conditions.
&&
.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 1054 PM CDT Mon Jul 15 2024
Light winds will become northwest and then increase to around 10
knots on Tuesday. Otherwise VFR conditions are expected.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
DISCUSSION...JM
AVIATION...Boyne
Area Forecast Discussion
National Weather Service Cheyenne WY
605 PM MDT Mon Jul 15 2024
.KEY MESSAGES...
- Hot temperatures will continue through this afternoon for a
majority of the area today before tapering off temporarily
through mid-week.
- Increased precipitation chances and cooler temperatures are
expected this afternoon through Wednesday.
- Isolated severe thunderstorms are expected today and Tuesday.
The primary hazards are lightning, brief heavy rainfall, and
strong winds to 60mph.
&&
.SHORT TERM /THROUGH WEDNESDAY NIGHT/...
Issued at 235 PM MDT Mon Jul 15 2024
Cold front pushing into the CWA from the northeast this
afternoon...currently lays along a line from Bridgeport to
Douglas into central Montana. Radar beginning to show convection
developing just west of this front across northern Carbon/Albany
Counties...into Platte County. RAP analysis showing low level
CIN has eroded away with 20Z surface based CAPE 500 J/KG over
southeast Wyoming and just over 1000 J/KG over the Panhandle.
Looking at SBCAPE to continue increasing through the afternoon.
SPC mesoanalysis showing CAPE increasing to 1500-2000J/KG
through the late afternoon. Both HRRR and RAP simulated radar
showing a good coverage of convection across the CWA at 00Z.
Initially high based storms...main hazard will be strong
downburst winds of 60 mph or higher. By 00Z...PWATS looking to
be around 0.9 inch across southeast Wyoming and near an inch
over the Panhandle...so should begin to see rain hitting the
ground this evening for a time.
Front gets forced east Tuesday into western South Dakota and
western Nebraska. May be a bit less coverage of storms across
southeast Wyoming Tuesday as PWATS decrease in the drier air.
For the Panhandle however...their PWATS stay pretty high (over
an inch). May be dealing with marginally severe storms in the
Panhandle Tuesday afternoon.
Maybe better chances for convection Wednesday as ECMWF/GFS/NAM
and SREF all show that surface front surging west back into the
southeast Wyoming plains.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
Issued at 235 PM MDT Mon Jul 15 2024
After a brief break from the heat on Tuesday and Wednesday, the
ridge aloft will re-consolidate on Thursday and warm 700-mb
temperatures back up to around +15C over the area. The intensity of
this round of heat is expected to be less than what we just saw over
the weekend. Still, expect above normal temperatures with highs in
the upper 80s to 90s for most of the area. Thunderstorm coverage on
Thursday will be a little less than Wednesday due to lack of
forcing, but dewpoints in the 50s will still linger in the Ne
panhandle and far eastern Wyoming. As a result, still expect PM
shower and storm activity, just with lower coverage. An uptick in
activity is possible on Friday as a shortwave skirts over the top of
the upper level ridge and moves down its eastern flank. The added
lift from the nearby shortwave could enhance storm coverage a bit,
though ensembles differ in handling the strength and proximity of
this system. Generally have PoPs in the 30-50% range across the area
for Friday, which looks like the best chance of the long term
period.
The axis of the upper level ridge over the west responsible for the
recent hot weather will retrograde westward over the weekend,
allowing cooler air to spill into the Plains east of the Rockies.
Temperatures on Saturday and Sunday will be near to slightly below
normal for this time of year as more surface cold fronts are
permitted through our area. Daily chances for afternoon showers and
thunderstorms will continue through the weekend, but it is difficult
to get into the details at this time.
&&
.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 605 PM MDT Mon Jul 15 2024
The first line of thunderstorms this afternoon will exit the western
Nebraska Panhandle over the next hour. A second round is developing
behind this line across the mountain of southeast Wyoming and is
forecast to impact most terminals between now and 05z, including
western Nebraska later this evening. Activity is expected to weaken
and push east after 05z late this evening.
HAZARDS/WEATHER TRENDS: VFR conditions will prevail in between
thunderstorms. However, brief (Less than an hour) IFR conditions
are possible with these thunderstorms as they move rapidly eastward.
In addition, frequent lightning, small hail, and very gusty winds
are possible until 05z late this evening. Conditions will improve
by midnight (06z).
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.
&&
$$
SHORT TERM...GCC
LONG TERM...MN
AVIATION...TJT
Area Forecast Discussion
National Weather Service Des Moines IA
634 PM CDT Mon Jul 15 2024
...Updated for the 00z Aviation Discussion...
.KEY MESSAGES...
- Enhanced Severe Storm Risk Through Evening with Risk of Higher
End Damaging Winds, Some Hail and Possible Tornado
- Heat Advisory in place to this evening South
- Cooler and Mainly Dry Tuesday through Sunday
&&
.DISCUSSION...
Issued at 221 PM CDT Mon Jul 15 2024
Confidence Short Term: Medium
Warm layer aloft still holding down convection at 1815z with cu
field showing up along one of the many weak boundaries over the
region. The overall synoptic set up is the same with a trough of low
pressure from northern Wisconsin back to western MN, then south to
western Iowa. Weak lows are present in western MN and near Omaha.
VISSAT shows the area of cu and also the same location of the
highest SBCAPE of 6000 to 7000 J/kg and surface moisture
convergence. Currently there remains some weak MLCIN over
western Iowa where some convection is trying to fire. However,
just to the east of where some storms are beginning, the area is
totally uncapped with 4000 to 4500 J/kg MLCAPE. The more
widespread initiation is still expected between 21 to 22z.
Though the earlier HRRR runs today have been backing off on our
area to some degree, the latest 17z HRRR is now initiating
convection around 20 to 21z and quickly filling in an area of
discrete storms around US20 US30 corridor. This then grows
upscale into northern and west central Illinois. Trailing severe
convection begins to fill in between US20 and I80 between 22z
and 01z. So, holding on to similar thinking with the potential
still there. While the potential for widespread high end wind
event may be reduced slightly in this scenario, we should still
see some pockets of significant damaging winds within the
clusters of storms. The good news is that most of the storms
should exit the region around 02 to 03z and the remainder of the
night relatively quiet. Tomorrow was originally expected to be
dry, but there is another weak wave over Montana tracking
southeast. This may bring a few showers/isolated storms to the
region by Tuesday afternoon. The main theme for tomorrow and
moving forward is cooler temperatures. Highs tomorrow will range
from the upper 70s north to the lower to mid 80s south.
Tomorrow night as high pressure settles into the region, any
lingering showers should come to an end with cooler overnight
mins in the upper 50s to mid 60s.
.Long Term /Wednesday through Monday/...
Confidence: Medium
Most of the week will remain dry with cooler temperatures in the 70s
to lower 80s. Toward the weekend, we return to southerly flow with
chances once again for some convection by late Friday night west.
This trend will extend into the weekend, but with lower confidence
on coverage and timing. Temperatures should remain pleasant and in
the 70s to lower 80s.
&&
.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 634 PM CDT Mon Jul 15 2024
Storms continue moving southeast of most sites, with the
exception is OTM. Will monitor storms. Have timed out arrival.
Most of the remainder is clear. Expecting VFR conditions to
follow for tonight. Some potential for scat showers tomorrow
afternoon. Will leave for 06z TAF package to handle. /rev
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 8 PM CDT this evening for IAZ057>062-
070>075-081>086-092>097.
&&
$$
DISCUSSION...REV
AVIATION...REV
Area Forecast Discussion
National Weather Service Hastings NE
631 PM CDT Mon Jul 15 2024
.KEY MESSAGES...
- Heat Advisory remains in effect until 8 PM for all but the far
north fringes of our coverage area (CWA). Although Tuesday
will be "somewhat hot" especially in our KS counties, we can
thankfully wave GOODBYE to truly dangerous/excessive heat for
the foreseeable future (high temps mainly between upper 70s
and mid 80s most places over next week).
- While our entire CWA is officially under either a
Marginal/Slight risk for severe storms later this evening-
overnight, we are getting overall MORE CONCERNED about Tuesday
afternoon-evening severe storm potential as storms develop
along a secondary cold front and move south-southeastward
through the area.
- Beyond Tuesday: While it will certainly be dry more often than
not, the Wed night-Monday time frame features
several/intermittent (and mainly low-confidence)
rain/thunderstorm chances for various parts of the CWA. At
least for now, the overall-highest/most widespread chances
(PoPs) are focused Fri night.
&&
.DISCUSSION...
Issued at 459 PM CDT Mon Jul 15 2024
-- PRIMARY CHANGES TO THIS 7-DAY FORECAST "PACKAGE" VERSUS THE
PREVIOUS ONE (issued early this AM):
- As already mentioned above, concern has increased somewhat for
a potential severe storm threat Tuesday afternoon-evening, as
latest models have come in a bit more aggressive with
development along a secondary cold front dropping southward
through the area. Agree with SPC in "upgrading" essentially
our entire CWA from a Marginal Risk (level 1 of 5) to a level
2 Slight Risk.
-- 7-DAY FORECAST OVERVIEW/HIGHLIGHTS:
- CURRENT/RECENT WEATHER SCENE AS OF 4 PM:
Today has pretty much played out as expected. We remain in the
grips of our LAST day of excessive heat, with actual high temps
on track to range from mid 90s for most Neb zones, to upper 90s
along the state line, to 100-108 in KS. Thanks to dewpoints
still well into the upper 60s-mid 70s range across the majority
of our Neb CWA, heat index values are still solidly into the
100-108 range across the majority of the CWA. Our Heat Advisory
continues as-posted until 8 PM...considered trimming off a few
northwestern counties where heat index is "coolest", but even
there heat index is still into the 90s so opted to just let it
ride.
In the big picture of the mid-upper levels, water vapor
satellite and short term model data confirm broad west-
northwesterly flow aloft, as we remain in between the center of
expansive ridging/high pressure centered over northwest NM, and
a large-scale trough centered over southeast Canada into the
Great Lakes region. On the smaller scale, a low-amplitude
disturbance is pushing southeastward into mainly IA, where
strong to severe storms have blossomed. At the surface, although
it obviously hasn`t cooled us off much yet, a MUCH-WELCOMED cold
front continues marching south across our CWA and has reached
far northern KS. In it`s wake, north-northeast breezes are
sustained generally 10-15 MPH/some gusts 20+ MPH.
- THIS EVENING-OVERNIGHT:
With weak forcing aloft to the west of the IA convection, along
with warm air aloft/capping in play, our CWA is expected to
remain well west of any convection developing to our east, and
at least for several more hours, should also remain well east of
any convection developing off the High Plains/Foothills of
CO/WY. However, mainly sometime AFTER 10 PM, higher-res short
term models (particularly HRRR), suggest that a broken line
and/or cluster/complex of convection will likely arrive into our
CWA from the west. Although have at least slight chances (20%)
across our entire CWA for the late evening-overnight hours, have
the highest chances (currently 50% but possibly not high enough)
focused within our far western and especially southern/KS zones.
Latest HRRR suggests that IF our CWA is subjected to any severe
storm threat tonight, it would mainly focus 11PM-3AM in
association with a possible storm complex/MCS rolling mainly
along/especially south of the NE-KS border. Main hazards would
likely be 60+ MPH winds, with a somewhat lesser threat for hail
to around quarter size. While the main batch of storms would
likely depart our far east-southeast zones by around 3-4 AM,
left small PoPs intact through the rest of tonight to account
for possible spotty "residual" weaker storms.
In other departments overnight, made little change to low
temps...aimed from mid-upper 60s north to low 70s far southeast.
With light winds late in the night, suppose some mainly
patchy/light fog cannot be ruled out, but kept out of forecast
as current expectation is for cloud cover to be a mitigating
factor.
- TUESDAY DAYTIME-OVERNIGHT:
While most places are likely to be dry in the morning through at
least early afternoon, have some low PoPs in to account for at
least isolated, non-severe storm activity. However, at some
point in the 4-7 PM time frame, things are expected to get
active along a secondary cold front arriving from the north. For
only being 24 hours out, models still show a fair amount of
uncertainty in the "exact" arrival of this front and associated
threat (HRRR closer to 4 PM...NAMNest closer to 7 PM). Either
way, once storm do develop, the environment will be favorable
for initial, at least briefly isolated/maybe supercellular
storms, that would then grow upscale into at least a broken
line/cluster as they track south-southeast. Fully agree with SPC
on the upgrade to Slight Risk (level 2), as healthy mixed-
layer CAPE of 2500-3500 J/kg in the presence of 35-40KT of deep
layer shear should be enough to stir up some trouble...mainly in
the form of hail to at least ping pong ball size/gusts to at
least 60 MPH. Based on current timing, the main severe threat
should exit our southern zones by around 11 PM-Midnight, with
most areas then likely storm-free the rest of the night.
In other Tuesday departments, although it WILL BE COOLER than
today, it won`t exactly be refreshing either. In fact, high
temps have trended up a few degrees...currently aimed mid 80s
most Neb zones, upper 80s-low 90s near the state line and mid
90s far southeast (esp Osborne/Mitchell counties). So better,
but not exactly cool by any means.
- WEDNESDAY-THURSDAY:
As cooler/drier (more stable) air arrives from the north-
northeast, things should certainly turn less active. In fact,
the Wednesday daytime -evening forecast is currently dry, with
only some "iffy" slight PoPs in far western zones late Wed
night. Winds Wed will be out of the northeast generally 10-15
MPH, and it will be the overall-coolest day we`ll have seen in
over a week with highs aimed mainly upper 70s-low 80s (a few mid
80s possible mainly KS).
Like Wed, Thurs-Thurs night will likely be mainly dry as well as
we remain under uneventful northwesterly flow aloft, but there
are some small PoPs mainly west. Highs again mainly upper
70s-low 80s, but more mid 80s south-southwest.
- FRIDAY-SATURDAY:
Although still several days out and far from a "sure thing",
latest ECMWF/GFS agree that a shortwave trough will drop
southward into our region...thus sparking our overall-highest
(widespread 50-60%) rain/thunderstorm chances of the week for
Friday evening-overnight. Lower chances continue into Saturday,
which should be mostly dry. Temp-wise, Friday warms up a touch
with more widespread 80s (pushing 90 far southwest), but then
cool down again Saturday (mainly upper 70s-mid 80s).
- SUNDAY-MONDAY:
Various, low-end/low-confidence PoPs continue, as there are
signs of at least weak disturbances in the area (more so GFS
versus ECMWF). As usual that far out, confidence is higher in
temps. At least for now, our official forecast MIGHT be a bit
too cool advertising highs mainly mid-upper 70s, but even if it
trends up a bit with time...should not be any warmer than low-
mid 80s.
&&
.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 612 PM CDT Mon Jul 15 2024
For KGRI/KEAR Airports:
Prevailing VFR conditions expected through the period with a
small chance for a thunderstorm or two possible after midnight.
The developing line of TSRAs to our west is expected to weaken
as they approach our western fringe (Dawson county) late this
evening, with a VCTS possible aft 16/05Z as this line pushes
east southeastward. Behind this line, expect a mid level cloud
deck near 10KFT to persist through the overnight hours...and
with light winds and elevated dewpoints, could see a bit of
light BR...although would prefer less mid level clouds to have
anything more significant. Mid level clouds are forecast to
linger across the local area through much of the day Tuesday,
with more breaks during the afternoon hours, before another
front brings an additional chance for TSRAs to the terminals
Tuesday evening.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...Heat Advisory until 8 PM CDT this evening for NEZ048-049-
060>064-072>077-082>087.
KS...Heat Advisory until 8 PM CDT this evening for KSZ005>007-
017>019.
&&
$$
DISCUSSION...Pfannkuch
AVIATION...Rossi
Area Forecast Discussion
National Weather Service Gray ME
1130 PM EDT Mon Jul 15 2024
.SYNOPSIS...
Heat and humidity build for the next few days as high pressure
strengthens off the Eastern Seaboard, with chances for
scattered afternoon showers and thunderstorms each day. A cold
front moves through late Wednesday through Thursday, bringing
drier and somewhat cooler conditions for the end of the week and
going into the weekend with high pressure building in from the
west.
&&
.NEAR TERM /UNTIL 6 PM TUESDAY EVENING/...
1130 PM Update...Mid level short wave associated with a remnant
MCV is showing signs of weakening as it lifts northeastward
across the Adirondacks towards the St Lawrence Valley. Latest
regional radar mosaic shows an area of showers with embedded
thunder moving northeast into Vermont with lightning activity on
the downward trend. Surface obs over Upstate NY into northern
VT show some recent wind gusts to around 30 mph and rainfall
rates nearing one inch per hour. Overall no major changes with
this update with some tweaks to PoPs as the area of showers and
embedded thunder slide across the northern half of NH and far NW
Maine. Since this activity is on the downward trend... little
in the way of impacts are expected from this rain. The southern
half will likely see little in the way of measurable rainfall
with patchy fog possible along the coastal plain.
7 PM Update...Convection that has be ongoing across Mass has
remained well south of the NH border and have trimmed back PoPs
in the near term across southern NH. Latest satellite shows CU
fields have started to dissipate across the forecast area with
mostly fair skies prevailing and therefore have also decreased
the sky cover forecast. The main item of interest is an MCS
marching across the Finger Lakes region of NY. Recent runs of
the HRRR and the 18Z NamNest maintain good agreement that this
MCS will weaken as it crosses the Hudson Valley and moves into
VT around Midnight tonight. Models suggest this feature will
continue to weaken as it crosses into NH after midnight with few
rumbles of thunder possible and some brief heavy rain. Will
continue to monitor this feature through the evening, while the
overall threat for strong thunderstorms is on the downward trend
based on the latest model guidance.
Previously...
Visible satellite imagery this afternoon shows some diurnally
driven cumulus across the area with some cirrus streaming over
southern NH. The latest RAP13 pressure analysis shows a sfc
trough moving across southern New England, which is helping to
spark scattered showers and thunderstorms over Central
Massachusetts. Latest CAMs suggest most of this activity should
drift east and south of NH over the next couple of hours but it
is possible some additional storms develop within the outflow
boundaries associated with the ongoing convection. It will
otherwise continue to be a hot and humid afternoon and early
evening with just an isolated shower or storm. Any storm will be
capable of producing locally gusty winds and briefly heavy
rainfall.
Our attention tonight will be focused on a gradually weakening
MCS/MCV that is currently moving across western NY state. This
system is progged to continue moving east-northeastward this
evening and through tonight before arriving towards VT within an
hour or so either side of 10 PM. Latest CAMs indicate a
continued weakening trend as it arrives in our area by or a
little after midnight with the main focus moving into southern
Quebec. The environment will remain somewhat favorable though
through the night for strong to locally severe storms as the h8
LLJ strengthens, increasing the 0-6km shear to around 35 kts
with around 1500 J/KG of MUCAPE to work with. As a result, while
the threat for overnight convection and possible strong to
severe storms is low it cannot be completely ruled out as CAMs
tend to struggle with these types of setups. Strong to locally
damaging winds, heavy rainfall, and frequent lightning would be
the primary threats.
It will otherwise be a warm and muggy night with lows into the
upper 60s to lower 70s. Patchy fog will be possible overnight as
well.
&&
.SHORT TERM /6 PM TUESDAY EVENING THROUGH WEDNESDAY/...
Hot and humid conditions will persist on Tuesday with high
temperatures into the lower to middle 90s south of the
mountains. Cooler temperatures will be common across the far
north, mountains, and along the Mid-Coast/islands. A Heat
Advisory has been issued for most locations south of the
mountains and away from the Mid-Coast with heat indices into the
95-100 degree range during the afternoon. Additional scattered
showers and storms are possible during the afternoon and evening
as a s/w crosses over the region. Any storms will be capable of
becoming strong to severe with damaging winds the primary
threat. The Storm Prediction Center has placed most of NH into a
MRGL risk for severe storms.
Storms diminish Tuesday night paving the way to another warm and
muggy night with lows primarily into the 70s. Fog will be
possible once again, especially in locations the receive earlier
rainfall.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
Models have been fairly consistent over the last few days for
breaking the heat wave come Wed night and Thursday as a more
localized -NAO sets up over Greenland and the Atlantic poleward
of 50 N. This does help break down the ridge, but there is so
much warm over central and western Canada that there really
isn`t much of source to cool things down, but itll be more
along the lines of less warm, with temps running normal or a
little above. However, once we clear the hot air out, it will be
mainly dry Friday into early next week, with daytime temps
mostly in the 80s, and overnight light in the mid 50s to mid
60s.
Wednesday shot be the last hot and humid days, and while we
will probably need another heat advisory in S NH and SW ME,
there are still questions as to how quickly clouds/SHRA/TSRA
move in ahead of the front, and thus, how will warm it will be
in points N and E. As for the front, there still questions with
its timing as we will have to see how it reacts to the wave
interacting with it Tuesday night, and then again a second wave
that moves through late Wed night or Thu, and where and when the
second one develops will be dependent on the first. So, while
some SHRA/TSRA will be possible Wed afternoon, especially in the
mtns, the bulk of any convection will likely be Wed night, and
precip amts will depend on what happens with the front. Its
unlikely that we will clear the high humidity out of here Wed
night, although mins will be a little lower especially in the
mtns, generally in the 60s.
Thu will also depend on what happens with the front, but, as we
often see with cold fronts in the summer, if it doesnt get
through before dark, it will likely not mix down until nest
morning, and because we may rain overnight into Thu morning, may
not see the drier air mix down until later in the day, so,
while it ill not be as hot but itll still be humid. The good
news is, we should see the effect of that cold front by Thu
night with clearing and lower humidity, with mins in the mid 50s
in the mtns to 60 to 65 in the S.
Friday through the weekend will be dry and sunny. More
comfortable RH are expected Fri with highs 75-80 in the mtns and
low to mid 80s in the S and lows Sat morning in the mid 50s to
low 60s. Sat and Sunday will be a few degrees warmer, with highs
mostly in the 80, but will start to see the RH creep up a bit by
Sunday. Monday looks dry and warm as well.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
Short Term...VFR conditions dominate tonight through Tuesday
night outside of any FG, which could result in IFR to LIFR
restrictions. The greatest potential for this will be at KHIE,
KLEB, and KRKD. Scattered SHRA and TSRA are possible late
tonight and again Tuesday afternoon and evening with locally
strong winds and +RA the primary threats. No LLWS is expected
outside of any TSRA.
Long Term...Some valley fog possible lingering into Wed morning,
but should return to VFR through the rest of the day. Sct TSRA
will develop inland during the afternoon as a front approaches
and move through Wed night. This is the best to see several
hours or more of flight restrictions as fog settles in behind
any rain that does fall. Flight restrictions could linger into
Thu morning, but should see improvement to VFR during the
afternoon. Thu night through the weekend will be mainly VFR, the
only exception being late night valley fog.
&&
.MARINE...
Short Term...South-southwesterly winds will persist through
Tuesday night. Although winds will primarily remain below 25
kts, a few gusts to near 25 kts will be possible at times.
Scattered showers and storms will remain possible, some of which
will contain locally stronger winds. Seas will be at 2-4 ft,
highest outside of the bays. Marine fog will be possible at
times.
Long Term...Generally winds/seas stay below SCA levels through
the coming week, but could approach SCA gusts/seas Wed night
into early Thu.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...Heat Advisory from noon to 8 PM EDT Tuesday for MEZ012-018>024-
033.
NH...Heat Advisory from noon to 8 PM EDT Tuesday for NHZ004-006-
008>015.
MARINE...None.
&&
$$
SYNOPSIS...Tubbs
NEAR TERM...Schroeter/Tubbs
SHORT TERM...Tubbs
LONG TERM...Cempa
Area Forecast Discussion
National Weather Service Indianapolis IN
1007 PM EDT Mon Jul 15 2024
.KEY MESSAGES...
- Thunderstorms with damaging wind potential late this evening and
tonight
- Flash flooding possible across portions of the area tonight
through tomorrow
- Pleasant weather with cooler temperatures and lower humidity Thursday
into the weekend
&&
.FORECAST UPDATE...
Issued at 1007 PM EDT Mon Jul 15 2024
A severe QLCS across northern and central Illinois continues to
march east southeast this evening. The environment ahead of the
storms remains very unstable, with MLCAPEs of 4000-5000 J/kg.
The storms in central Illinois appear to be moving southeast along
the old boundary that was seen on visible satellite earlier this
afternoon. Given that track and current speed puts the storms in far
western/northwestern central Indiana between 11pm and midnight.
Given the available instability, even with some diurnal weakening
there will be plenty left for the storms to feed on. The question
remains on whether the cold pool from the storms will race out ahead
of the line enough to weaken them.
HRRR/WoFS both show the storms remaining well defined as they enter
the forecast area, but both show some weakening as they move deeper
into central Indiana. Will watch closely, but still feel that
damaging winds remain a decent threat across the northern forecast
area into the overnight hours. (Note that the storms are moving
faster than the latest HRRR runs.)
Heavy rain will also remain a threat tonight as the low level jet
may cause additional storms to train on the western side of the line
overnight.
Thus, for now, overall thinking of severe threat and flooding threat
remains relatively unchanged. Tweaked PoPs based on latest radar and
model trends. Also made some minor changes to temperatures given the
expected rain cooled air behind the line.
&&
.SHORT TERM (This evening through Tuesday)...
Issued at 207 PM EDT Mon Jul 15 2024
An active convective period continues with challenges regarding
thunderstorm timing and intensity, inherent to uncertainty with
mesoscale details. It appears that thunderstorm formation this
afternoon will be limited or non-existent across central Indiana,
and a round of thunderstorms will arrive late this evening with
damaging wind potential into the night. We are also concerned about
flash flooding potential tonight through part of tomorrow. See
meteorological analysis for more details.
On the synoptic scale, we remain on the southern periphery of
midlevel westerly flow. Perturbations within the flow are likely
significantly augmented by diurnal convective blow-ups. Modeling of
this process requires mesoscale precision in the initial conditions
that isn`t always possible, and can spiral into chaos quickly. This
is the reason for the diversity we`re seeing among the CAMs with
regards to placement and timing of convection. It is important not
to focus on any one specific model in this pattern.
Our three main concerns as far as weather impacts are:
1. Dangerous heat
2. Severe thunderstorms with damaging wind
3. Flash flooding
In regards to the near-term heat, through early evening temperatures
and dew points will be high enough to meet traditional Heat Advisory
criteria (105F heat index) across portions of central Indiana. In
the latest ACARS vapor sounding and short term model guidance, it
appears that moisture depth is sufficient to preclude mixing of
drier air and meaningful fall dew points through the diurnal peak.
Southwesterly breeze and some cloud cover from diurnal cumulus are
components that will keep the Wet Bulb Globe Temperature risk
category contained slightly, though still "high".
Thunderstorm development today should be isolated at most given
residual subsidence-enhanced capping. Evidence of this can be seen
in laminar flat look to cumulus field in visible satellite imagery
all the way back into Illinois. Water vapor channel imagery shows
core of the subsidence moving east early this afternoon. It`s
possible the stronger capping may exit before peak diurnal period
sufficient for a few convective cells, especially near any residual
mesoscale boundaries, but this is low probability.
Upstream over Iowa and closer to the influence of a weak midlevel
impulse, diurnal convection will develop later this afternoon. Given
the magnitude of instability, thunderstorms should become quite
robust. This will occur at the southern periphery of stronger
westerlies aloft and sufficient shear values for a forward-
propagating MCS to evolve. The downstream environment would favor
approximately 30-40 mph east-southeasterly system motion. Moderate
shear would probably support trailing stratiform rain quickly
evolving and enhancing the cold pool, perhaps more than modeled.
Thus, confidence in an MCS impacting a good portion of central
Indiana late this evening and overnight is fairly high. Wind damage
is the primary threat and there is at least a low chance of
significant wind damage, especially earlier in the night before it
begins to outpace the better parameter space. Northwest portions of
central Indiana, including Newport, Lafayette, Crawfordsville, and
Kokomo have the highest potential for wind damage, tapering somewhat
with southeastward extent into the Indy metro and eastward later in
the night.
Flash flood concerns today and tonight are multi-faceted. Given
recent rainfall (1-2 inches and locally higher over the past 72
hours) even a quick-moving forward-propagating MCS with limited
duration of heavy rates could have some flash flood concern. These
systems tend to be quite efficient rainfall producers in a short
amount of time, and could easily exceed latest RFC 1-hour flash
flood guidance of around 1.50 inches across the northern third of
central Indiana. This would yield marginal/low-end flooding or flash
flooding, most likely.
Of greater concern is a relatively low probability scenario later
tonight on the western flank of MCS cold pool, and how it interacts
with the low level jet. It appears back-building and training are
possible across a focused area that is difficult to pin down at this
time. Warm cloud depth is seasonally large with model indications of
rich moisture in this layer. In fact, overall precipitation
efficiency may be enhanced by an east-west band of mid-upper level
moisture. Uncertainties remain on where a mesoscale convective flash
flooding scenario could potentially evolve, but the potential
magnitude despite spatial coverage combined with aforementioned more
widespread low-end threat justifies a Flood Watch.
Uncertainties grow further tomorrow on the severe and flooding
potential. This will largely depend on where the remnant MCS cold
pool resides during the afternoon once diurnal destabilization
occurs. The synoptic front will still be lagging to the northwest so
another active convective day seems likely, largely driven by
mesoscale details that we can`t resolve with precision at this time.
There may be an ongoing flood/flash flood threat early with residual
convection, given indications of modest instability remaining and
the aforementioned reasons for potentially locally heavy rainfall
amounts. In addition to flooding, moderate instability developing
later in the day but with marginal deep layer shear should mean
sporadic damaging wind potential from loosely organized multicell
clusters is the main severe threat. Again, this is conditional on
mesoscale details, as one plausible scenario would hold this threat
primarily to our south.
There is some potential for dangerous heat across far southern
portions of our forecast area tomorrow. We will not issue a Heat
Advisory at this time due to uncertainties on how far south the cold
pool from overnight convection will be, residual midlevel clouds,
and potential ongoing convection or development before peak heating.
Will reevaluate tonight and early tomorrow based on trends with
convection.
&&
.LONG TERM (Tuesday night through Monday)...
Issued at 207 PM EDT Mon Jul 15 2024
Wednesday, it appears that the synoptic front will be across our
south or just south of the area. We`ll continue low probabilities
but confine them a little further south than the previous forecast.
Drier/cooler continental air mass will lag some until the amplifying
synoptic trough axis moves through late Wednesday. The air mass
change will be most noticeable Thursday continuing into the weekend
before gradually modifying Sunday into early next week. Moisture
returns then, but the synoptic flow pattern is rather quiescent.
Organized precipitation appears unlikely but we may enter a scenario
next week with diurnal isolated to scattered convection daily. After
a period of 5-10F negative temperature anomalies relative to mid-
July climo, temperatures should return to near climo next week. For
the day 8-14 day period there`s not a strong signal of above or
below average precipitation or temperatures at this time.
&&
.AVIATION (00Z TAF Issuance)...
Issued at 749 PM EDT Mon Jul 15 2024
Impacts:
- Line of weakening thunderstorms moving through overnight from
northwest to southeast. MVFR or worse possible in this.
- Nonzero chance of MVFR ceilings Tuesday morning
- Southerly wind gusts to around 20kts Tuesday
Discussion:
Current convection should remain south and east of the TAF sites.
Focus then turns to a thunderstorm complex that will move in after
04Z. Unfortunately questions still remain in specific timing and how
long it will survive southeast.
For now, added a TEMPO group to KLAF/KIND, with highest confidence
in this TEMPO for KLAF. Strong winds are possible in these storms
along with MVFR and worse conditions.
After the storms exit, some light showers may linger with a lower
potential for MVFR ceilings. Additional storms could develop Tuesday
afternoon.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
Flood Watch through Tuesday afternoon for INZ021-028>031-035>049-
051>057.
Flood Watch from 8 AM EDT Tuesday through late Tuesday night for
INZ060>065-067>072.
&&
$$
UPDATE...50
SHORT TERM...BRB/Ryan
LONG TERM...BRB
AVIATION...50
Area Forecast Discussion
National Weather Service Morristown TN
903 PM EDT Mon Jul 15 2024
...New UPDATE...
.UPDATE...
Issued at 900 PM EDT Mon Jul 15 2024
|Late afternoon and early evening storms have ended. Expect partly
cloudy skies south and mostly clear north with patchy fog forming
late. Temperatures this evening are in the mid 80s to around 90
and should cool slowly into the mid 60s northeast to mid 70s
southwest which will not change for morning lows in the update.
Change is to remove showers and storms except a few in eastern
mountains another hour or so. Tuesdays weather looks similar to
todays with isolated to widely scattered showers storms mid
afternoon to early evening in southern areas. Updated forecast
sent.
&&
.SHORT TERM...
(This evening through Tuesday)
Issued at 306 PM EDT Mon Jul 15 2024
Key Messages:
1. Isolated convection again on Tuesday with main coverage across
the south.
2. Continued hot temperatures with mostly dry conditions in the
short term.
Discussion:
Mesoanalysis is showing some areas of around 2000 J/Kg MLCAPE this
afternoon with isolated convection along the higher elevations,
mainly across western higher elevations of the Cumberland Plateau
and Clinch Mountains. Some gusty winds could be expected with the
stronger storms, but severe weather is unlikely. Areas that do
receive rain will have some patchy fog overnight into Tuesday
morning - such as the Sequatchie Valley.
The weak upper level trough/col will shift southeast on Tuesday
with weak southwesterly flow across far southeast Tennessee and
southwest North Carolina. Northwest flow and increased subsidence
will limit convection across the northern zones of our forecast
area with slight chance/chance PoPs across southern/southeastern
counties. MLCAPE will be near 2000 J/Kg according to RAP forecast
soundings with some dry air in the boundary layer keeping LFC
heights relatively high and providing a risk of localized winds
with the strongest pulse convection. Overall, the severe wind risk
is very low.
&&
.LONG TERM...
(Tuesday night through next Monday)
Issued at 306 PM EDT Mon Jul 15 2024
Key Messages:
1. Excessive heat is expected to die down with the passing of a
front and falling of pressure heights throughout the atmosphere.
2. The frontal passage will bring widespread storms across the area
Wednesday into Thursday. Higher than normal moisture may lead to
scattered showers for the remainder of the period.
Tuesday Night through Thursday Night
The period begins with the continuance of a ridging pattern for our
region, with a high pressure center located off the Atlantic Coast.
The shortwave trough to our southwest has been cut off and seems to
be drifting as a low pressure center further south throughout the
period. Ridging is ended by a frontal passage and a return to a
troughing pattern by Thursday. The timing of the frontal passage is
uncertain, but it seems to move into the area by Thursday night. The
ECMWF brings the front through our area quicker and a tad further
south than the GFS. Surface temperatures are expected to exceed 90
degrees once again on Wednesday, with heat indices likely to exceed
100 degrees due to increased humidity.
The frontal passage is proceeded by a stark rise in PWATs, with
values around 1.9 inches. The majority of our region is under the
WPC marginal risk for excessive rainfall due to the higher than
average moisture. Wind profiles signal the potential for training
convection which could lead to some higher rainfall amounts in
areas. Overall, MLCAPE values will be near or below 1000 J/kg for
much of the region, with the some localized higher values. Deep
layer shear is unimpressive ahead of the front but rises with its
passage, potentially leading to higher rainfall amounts on Thursday.
With this event, the potential of flooding is in question, however
we can expect the ongoing lack of precipitation to lower that
potential. The main risk of these storms is going to be locally
strong wind gusts.
Friday through Monday
We can expect the frontal boundary to linger over the area for the
remainder of our period after its initial passing. The GFS and
ECMWF signal a drop in pressure heights following the frontal
passage, which could lead to a break from the excessive heat. While
temperatures are likely to lower, PWATS remain unseasonably high,
which will allow weak instability to persist. Precipitation is
likely during this period and will be mostly diurnally driven and
not unlike most summertime convection. The southeastern ridge
strengthens towards the end of our period, however moisture remains
quite high for the time of year.
&&
.AVIATION...
(00Z TAFS)
Issued at 726 PM EDT Mon Jul 15 2024
VFR conditions should continue through the next 24 hours with
light winds. TSTMS vicinity of CHA and TYS until sunset tonight or
01Z, then rapid dissipation of showers and storms with low
chances Tuesday afternoon between 18Z and 00Z. Prob30 for TSTMS
are in afternoon forecast from south to north at all 3 sites at
that time.
&&
.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN 74 96 76 95 / 20 40 20 80
Knoxville McGhee Tyson Airport, TN 73 96 75 93 / 10 30 30 80
Oak Ridge, TN 72 95 74 93 / 10 20 30 80
Tri Cities Airport, TN 68 93 72 91 / 10 30 30 80
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
SHORT TERM...TD
LONG TERM....BW
AVIATION...TD
Area Forecast Discussion
National Weather Service Omaha/Valley NE
1046 PM CDT Mon Jul 15 2024
.KEY MESSAGES...
- Dangerous heat continues this afternoon, with heat index
readings of 100 to 110+ degrees.
- 20-40% chance of storms this afternoon and evening, with a 5
to 15% chance of severe storms. Highest chances near and east
of the Missouri River through 9 PM. Primary threats are
damaging winds and hail.
- Additional strong to severe storms possible Tuesday afternoon
and evening, especially in northeast Nebraska (30-50% chance
of storms, 10-20% chance of severe storms). Questions remain
on exact timing, but hail and damaging winds are the primary
threats.
- An extended stretch of cooler-than-average temperatures will
carry us into the weekend, with chances for widespread rain
increasing into next week.
&&
.DISCUSSION...
Issued at 304 PM CDT Mon Jul 15 2024
Early afternoon analysis showed a surface trough pushing
southeast through roughly the Omaha and Lincoln areas as of 3
PM with a surface cold front lagging behind in northeast NE. As
the front continues to push southeast, expect some storm
development along it, especially as you go east into IA where
the primary shortwave energy will be tracking. Farther west and
in our forecast area, things are a little more uncertain, with
less influence from the aforementioned shortwave meaning we`ll
largely have to rely on daytime heating and the relatively weak
convergence along the front. In addition, model soundings do
reveal a cap that will need to be overcome, but latest RAP
soundings continue to indicate it largely erodes just as the
front pushes into the Omaha area. If this pans out, expect at
least one or two spotty storms along the front possibly
extending into eastern NE. And while most CAMs suggest
everything remains east, they tend to struggle in the more
weakly forced environments like we`ll see, so tend to think
something like the 15.12Z NAM 3km will be close to what we see.
If something does go, there will be plenty of instability to
work with, with HREF mean MUCAPE in the 4000 to 5000 J/kg range.
Combined with deep layer shear around 30-40 kts, there would be
potential for organized severe weather. The main threats would
be damaging winds and large hail with weak low level shear
limiting the tornado threat. That said, can`t completely rule
out a brief spinup tornado with a boundary in the area. So
bottom line, there`s about a 20-40% chance we see a storm or two
in our area, with a 5-15% chance of severe weather. Highest
chances will be within a county`s width of the Omaha metro and
points south and east in roughly the 4 PM to 9 PM window.
Heading into Tuesday, we`ll finally see relief from the heat as
the front will have pushed well to our south. Still expect
highs in the mid to upper 80s, but it won`t be anywhere near the
triple digit heat indices we saw in previous days. Latest short
term guidance has also trended up a tick in severe weather
potential for Tuesday afternoon/evening as another surface
boundary pushes south through the area. Ahead of the front,
guidance suggests a decent, but narrow plume of instability
extends into northeast NE with deep layer shear once again in
the 30-40 kt range in vicinity of the boundary. As a result,
guidance is in fairly good agreement of a line of storms
developing near the NE/SD border, pushing southeast through the
area, and gradually weakening as they run out of instability in
southeast NE. Still some spread on exact timing of the boundary
and just how far southeast the severe weather threat will
extend, but seems like a day where we`d have a hail threat as
storms develop and then transition into a damaging wind threat
as storms congeal into a line.
Beyond Tuesday, expect a rather nice work week under
northwesterly flow aloft as surface high pressure dominates.
Can`t completely rule out a few stray showers at times with some
hints at some weak shortwave energy rippling through the flow
at times, but we should largely be dry through at least Thursday
and possibly much of Friday. The next more widespread storm
chances look to arrive by Friday evening with guidance in pretty
good agreement a surface boundary and stronger shortwave trough
slide into the area as surface high pressure pushes east. These
chances also look to linger off and on through the weekend.
Otherwise, expect high temperatures in the upper 70s to mid 80s
and lows in the upper 50s to mid 60s. Enjoy!
&&
.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 1044 PM CDT Mon Jul 15 2024
VFR conditions through the TAF period with northerly winds less
than 8 knots. There could be some showers in the vicinity
KOFK/KLNK 11-16z, but not confident it will reach KOMA at this
time. And then there could be thunderstorms late in the TAF
period after 00z, but too far to include a mention with this
forecast package.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...None.
IA...None.
&&
$$
DISCUSSION...CA
AVIATION...DeWald
Area Forecast Discussion
National Weather Service Paducah KY
648 PM CDT Mon Jul 15 2024
.KEY MESSAGES...
- A Heat Advisory remains in effect until Tuesday evening as
peak heat index values between 105-110 degrees are expected.
- Unsettled weather returns on Tuesday as a cold front slowly
moves towards the region. The greatest risk is from late
Tuesday into Wednesday when multiple rounds of showers and
thunderstorms are possible. A Flood Watch is now in effect
Tuesday evening into Wednesday morning across portions of
southern Illinois and southwest Indiana.
- High pressure will provide relief from the heat and humidity
beginning Thursday through Sunday.
&&
.UPDATE...
Issued at 646 PM CDT Mon Jul 15 2024
Updated aviation discussion for 00Z TAFs.
&&
.DISCUSSION...
Issued at 328 PM CDT Mon Jul 15 2024
The heat and humidity remains the primary concern in the short term
as dewpoints once again are running above model guidance in the mid
70s to near 80 degrees. This translates to a heat index between 105
to 110 degrees this afternoon and again on Tuesday. A Heat Advisory
remains in effect until 01z Wednesday with maxTs progged in the low
to mid 90s. Overnight minTs will also be a bit warm tonight in the
mid 70s. Otherwise, scattered CU has once again developed this
afternoon as a 500 mb ridge of high pressure remains located over
the SW CONUS.
A period of unsettled weather begins to arrive on Tuesday as a
leading 500 mb shortwave downstream from a trough ejecting out
of Canada provides forcing for ascent. The latest CAMs show a MCS
developing south of the one that will move through the Chicago
area later this evening. The general idea is for a decaying MCS
to move towards the I-64 corridor early Tuesday morning, but
forecast confidence is low on the spatial coverage of any pcpn.
The parameters do not look terribly concerning should
thunderstorms occur. Have limit PoPs to a 30-35% with blends of
NBM and CONSShort given the uncertainty. One implication the
morning convection will likely have is where a residual outflow
boundary sets up, as this will be the main focus for the heavy
rainfall potential Tuesday night. It is worth noting any
convection during the day Tuesday could also provide some
relief from the heat up north. Have leaned closer to the NBM
25th percentile due to the possibility of more cloud cover.
As a cold front slowly sags southeast Tuesday evening, shower and
thunderstorm coverage becomes more likely from northwest to
southeast as a baroclinic zone sets up. The RAP13 shows 3000-4000
J/kg of MLCAPE and limited effective bulk shear around 25 kts 00z
Wednesday. Given a theta-e difference of 25 degrees and 0-3 km lapse
rates around 7.0 C/km, there remains a marginal risk in SPCs D2
outlook for a few isolated gusty severe storms capable of
producing downburst across northern portions of the CWA late
Tuesday afternoon into Tuesday evening. However, instability
quickly wanes with the loss of diurnal heating as a transition
to a heavy rain risk remains the main concern Tuesday night.
The 12z HREF PMM and latest 18z HRRR both show locally up to 2-4+
inches setting up right along the I-64 corridor across portions of
southern Illinois and southwest Indiana where training convection is
becoming probable. There are still some model differences in
the exact placement as the aformentioned outflow boundary will
play a big role, but overall confidence is increasing in the
potential for heavy rainfall to occur across portions of the FA.
PWATs remain progged around 2.00 inches with a light LCL-EL
cloud layer mean wind around 15 kts south of the boundary. This
favors the potential for multiple thunderstorms that will be
capable of producing torrential downpours. For this reason, have
gone ahead and issued a Flood Watch from 00z Tuesday evening
until 12z Wednesday morning. Across the rest of the FA, up to
1-2 inches of rainfall remains possible as additional rounds of
showers and thunderstorms push south Wednesday into Wednesday
night.
By Thursday morning, the cold front will eventually push south of
the FA, allowing for dry air to filter in across the FA from
the northeast as sfc high pressure builds into the lower Ohio
Valley. MaxTs are progged only in the low 80s by the NBM
Thursday and Friday with minTs ranging from the upper 50s to
lower 60s Thursday night. Dewpoints around 60 degrees will
certainly make this airmass quite refreshing! Temps do gradually
moderate over the weekend as a 500 mb trough digs across the
central Plains, but look to still remain slightly below normal.
As a disturbance approaches from the south, daily shower and
storm chances gradually increase by Sunday as the following week
looks to start off a bit more unsettled.
&&
.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 646 PM CDT Mon Jul 15 2024
VFR conditions are anticipated through much of Tuesday. Remnants
of overnight convection to the north of the area will pose the
potential for scattered showers and thunderstorms across northern
reaches of the area late tonight into Tuesday morning, impacting
mainly KMVN and KEVV. Scattered thunderstorm development is also
possible late Tuesday afternoon into Tuesday evening across the
entire region. Southwest winds 5 to 8 knots will increase to 10
knots by late morning and afternoon on Tuesday. Some gusts to
15 knots are also expected.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...Heat Advisory until 8 PM CDT Tuesday for ILZ075>078-080>094.
Flood Watch from Tuesday evening through Wednesday morning for
ILZ075>078-081>083.
MO...Heat Advisory until 8 PM CDT Tuesday for MOZ076-086-087-100-
107>112-114.
IN...Heat Advisory until 8 PM CDT /9 PM EDT/ Tuesday for INZ081-082-
085>088.
Flood Watch from Tuesday evening through Wednesday morning for
INZ081-082-085>088.
KY...Heat Advisory until 8 PM CDT Tuesday for KYZ001>022.
&&
$$
UPDATE...RJP
DISCUSSION...DW
AVIATION...RJP
Area Forecast Discussion
National Weather Service Topeka KS...CORRECTION
629 PM CDT Mon Jul 15 2024
.KEY MESSAGES...
- Hot conditions continue into this evening with heat indices of
105-110 degrees. A Heat Advisory remains in effect through
8PM.
- Storm chances (20-30%) increase tonight into Tuesday morning
including the potential for a few strong to severe storms.
- Additional storms, some strong to severe, could impact the area
Tuesday evening and night.
- Much cooler Wednesday into the weekend with highs in the 80s.
&&
.DISCUSSION...
Issued at 234 PM CDT Mon Jul 15 2024
The persistent upper ridge across the Desert Southwest has
built slightly eastward through the day with several waves noted
rounding the apex of the ridge. The 12z TOP sounding showed
850mb temperatures near 27 degrees C with a subtle increase of a
degree or two through the day. This results in another very hot
and humid day with heat indices in the 100-110 degree range.
The Heat Advisory remains in effect through 8PM this evening.
A surface cold front/trough currently draped from Wisconsin into
northwest Kansas will be shunted south this evening and overnight by
a perturbation rounding the ridge. Ascent along the boundary and
from the passing wave is expected to be sufficient for at least
scattered convective development, although CAMs vary on the coverage
of storms. The HRRR depicts the most widespread coverage of
precipitation while others show little to no convection. Effective
shear of 20-25kts along with plentiful elevated instability would
support some strong to severe storms capable of producing damaging
wind gusts and large hail. Any storms exit the area by mid-morning
Tuesday.
A cooler airmass will be in place Tuesday behind the front with
850mb temperatures cooling to 22-24 degrees C. However, dewpoints
remain in the upper 60s to mid 70s, creating another hot, but not as
oppressive, day. Heat index values will reach the upper 90s to near
100 degrees along and south of Interstate 70 during the afternoon.
Convection could develop along and north of the first cold front
that stalls across southeast Kansas as CIN erodes during the
afternoon. Inverted-V soundings would support a damaging wind gust
threat with these storms, although confidence in development is low.
Better chances for storms (30-50%) come Tuesday evening and
overnight as a secondary cold front and shortwave swing through the
area. These storms could be strong to severe with models showing
elongated and straight hodographs combined with MUCAPE of 1000-2000
J/kg. Large hail and damaging wind gusts are the main hazards with
these storms. PWATs around 2" could lead to locally heavy rainfall
as well.
A drier and cooler Canadian airmass builds in for Wednesday,
bringing welcome relief from the heat with highs in the 80s and low
in the 60s through the weekend. Precipitation chances increase this
weekend as an upper trough dives south across the central CONUS.
&&
.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 630 PM CDT Mon Jul 15 2024
VFR conditions to prevail through most of the overnight hour.
Slow moving cold front to push through the area tonight. An
upper level disturbance and surface low pressure will move east
tonight. Associated thunderstorms will likely accompany the
surface low through the overnight hours. Expect impact at the
terminals with -TSRA by 09Z through 12Z.
&&
.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.
&&
$$
DISCUSSION...Flanagan
AVIATION...Byrne