Forecast Discussions mentioning any of "ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 04/05/23

AREA FORECAST DISCUSSION

National Weather Service Kansas City/Pleasant Hill MO

 626 PM CDT Tue Apr 4 2023

.Discussion...
Issued at 228 PM CDT TUE APR 4 2023

Key messages:

- Two rounds of severe weather are possible today, the first this afternoon/evening.
  All modes of severe weather are possible. The second round
  tonight will be in a line of storms with winds being the main
  threat however, a brief hail threat and weak tornado threat
  cannot be ruled out.

- Freezing conditions will be possible for most of the area Thursday
  morning.

Discussion:

This afternoon, the warm front has lifted north of the area leaving
the entire forecast area in the warm section. Strong WAA is
producing southerly winds of 40-45mph. NAM soundings continue show a
cap in place near the KC Metro and this is confirmed by aircraft
soundings. However, further south across central Missouri storms
have initiated along a boundary where CINH has all but dissipated
here explosive growth has been noted in an area of 2500-3000J/Kg of
CAPE and 60kts of 0-6KM shear. Storms have initiated over Bates and
Henry Counties and severe storms have become likely there moving
northeast through the afternoon. Given the CAPE/shear parameters all
modes of severe weather will be possible with this afternoon/evening
round of storms.

This afternoon, a dryline is analyzed over eastern Kansas with a
cold front extending further back to the west across north central
into southwestern Kansas. Tonight the surface front is expected to
overtake the dryline and allow another round of storms to develop
over northwestern Missouri to eastern Kansas. The main concern with
these storms will be for damaging winds as they quickly evolve into
a line. However, with shear perpendicular to the line, embedded
tornadoes cannot be ruled out especially across northern Missouri in
the vicinity of the surface low. In addition, with initial upscale
growth of the like of storms, large hail may be briefly possible.
This line of storms is then expected to quickly move east across the
CWA through the overnight maintaining a damaging wind threat and low
end tornado threat exiting the area well before sunrise.

Behind the front tonight into tomorrow, modest CAA will make for a
much cooler day with highs in the upper 40s to mid 50s. Tomorrow
night, high pressure will move into the area providing for light
winds and clear skies. This will allow temperatures to fall back
into the upper 20s and lower 30s. Although, conditions do not yet
warrant frost/freeze products, those who have sensitive vegetation
out will need to be mindful of that. The ridge of surface high
pressure will remain over the area on Thursday providing copious
sunshine but weak mixing, as such, highs will remain below normal in
the mid 50s to near 60. A warming trend is expected Friday through
Saturday with increase WAA through the period. By saturday highs
will be in the upper 60s to lower 70s. The only other chance for
precipitation beyond today will come on Sunday as a weak upper level
shortwave moves through the area. Severe weather is not anticipated
however showers and thunderstorms will be possible with highs in the
low to mid 70s. In the wake of the weak upper shortwave moving
through the area, upper level ridging builds back into the region on
Monday and Tuesday. This will allow highs to rise into the mid 70s
to mid 80s.

&&

.Aviation...(For the 00Z TAFS through 00Z Wednesday Evening)
Issued at 621 PM CDT TUE APR 4 2023

The primary aviation concern will be a line of storms moving
across eastern Kansas and western Missouri this evening. Storms
are expected to move into the terminals between 02-04Z with strong
winds possible with any storm and reduced visibility due to heavy
downpours. The line of storms should be moving out of the
terminals by 04-06Z with ceilings scattering out and winds
gradually decreasing through the day Wednesday.

&&

.Fire Weather...
Issued at 402 AM CDT TUE APR 4 2023

Today will bring exceptionally breezy conditions to the bulk of
the forecast area. Southerly winds will increase through the day
to around 30 mph, with gusts approaching 40 to 50 mph at times.
Good surface moisture will be in place for the early part of the
day, but by mid to late afternoon areas across eastern Kansas and
far western Missouri will see a rapid plummet of surface moisture
as very dry and breezy air moves in from the west. Expect extreme
fire conditions across northeast Kansas and northwest Missouri as
a result of this airmass. Further east, winds will be very strong,
but RH values should remain around 40 percent with good low level
moisture in place. Winds will shift dramatically from the west-
northwest late this evening through the overnight.

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
KS...Red Flag Warning until 9 PM CDT this evening for KSZ025-102-103.

     Wind Advisory until 1 AM CDT Wednesday for KSZ025-057-060-
     102>105.

MO...Red Flag Warning until 9 PM CDT this evening for MOZ001-002-011-
     012-020-028.

     Wind Advisory until 1 AM CDT Wednesday for MOZ012>015-020>023-
     028>031-037>039-043>045-053-054.

     Wind Advisory until 1 AM CDT Wednesday for MOZ007-008-016-017-
     024-025-032-033-040-046.

&&

$$

Discussion...73
Aviation...PietrychaP
Fire Weather...Leighton



Area Forecast Discussion

National Weather Service Indianapolis IN

 919 PM EDT Tue Apr 4 2023

.Forecast Update...
Issued at 916 PM EDT Tue Apr 4 2023

Convection over MO/IL may lead to some elevated cloud cover, but
otherwise skies should remain scattered to broken over the next
several hours. Around 04-06Z, an increase in 850-700mb winds along
with decaying convection from upstream will leave to greater cloud
cover in the low levels. Given the expansive mid level dry layer, any
upstream convection should dissipate before reaching central Indiana
until the early morning which moisture flux from the SW increases.

With that said, the severe threat overnight in central Indiana will
be very limited outside of a rogue thunderstorm reaching NW
portions of the region between 07-09Z.

As day break approaches, the LLJ axis will near from the west and
mid to low level moisture should increase fairly rapidly, allowing
for isolated to scattered showers and thunderstorms. Buoyancy wont
be quite as robust in the early morning, but shear should be
sufficient for occasional downbursts with this first wave. This
threat looks to push though central Indiana between 11-14Z.

The primary severe threat will be later that morning into the early
evening as frontal forcing allows for scattered to numerous surface
based thunderstorms. Even if the morning convection weakens mid
level lapse rates, there should be enough instability and shear for
organized strong to severe thunderstorms. The biggest uncertainty
currently is the convective mode, of which will have a direct
influence on potential hazards. For now, the expectation is for
damaging wind to be the primary threat, but any broken, QLCS type
features would increase the tornado threat. One important feature to
pay attention to tomorrow is the storm motion. Any deveint right
mover will be able to ingest much more helecity and therefor
increase the tornado threat greatly. Hail will also be a concern,
but will depend on the moisture profile, so uncertainty remains on
how widespread the hail threat will be.

&&

.Short Term...(This evening through Wednesday)
Issued at 252 PM EDT Tue Apr 4 2023

*Multiple rounds of convection expected late tonight through the day
Wednesday

*Some severe storms are likely, but uncertainty remains on which
round of storms will have the highest likelihood of severe

*Windy outside of storms Wednesday

Rest of This Afternoon...

Clouds covered much of central Indiana early this afternoon, with
some breaks in the southwest. Where clouds remained thick,
temperatures were in the lower 60s. Where sunshine has mixed in,
readings were in the 70s.

Expect the clouds to the north to break up some and temperatures
warm through the remainder of the afternoon. All areas should be at
least in the 70s, with some 80s in the south.

A few showers can`t be ruled out in the far northeast, but odds are
too low to mention in the forecast.

This evening into the early overnight...

Quiet weather will be across central Indiana during this period, as
convection develops well to the west in the warm sector. Southerly
winds will continue to bring in warm air, keeping the evening warm
and humid. Low level winds aloft will increase, so some mixing will
allow some wind gusts at the surface.

Overnight through Wednesday...

Multiple rounds of convection are expected late tonight through the
day Wednesday. Strong shear and plentiful moisture will be present
throughout the day. Strong winds will be present not far off the
surface and will be able to be brought down. Thus, it will come down
to available instability and mesoscale features created by
convection.

Believe there are at least a couple of potential scenarios for
Wednesday, similar to previous thoughts...

1) Strong to severe convection will persist from the Ozarks into
central Indiana late tonight into early Wednesday morning. After
this, there will be a lull before more convection develops along the
cold front by mid afternoon. Severity of the second line will depend
on how much instability builds between the two rounds.

2) Convection from the Ozarks weakens before it arrives here and
dissipates across the area. Additional thunderstorms develop in
unstable air mid morning to early afternoon. This convection may be
severe if instability is able to build enough. Additional convection
then forms along the front later in the afternoon, which may be
severe if atmosphere can recover.

In summary, enough ingredients are there so that some severe storms
are likely. Damaging winds will be the highest threat, but given the
amount of shear, potential boundaries from previous rounds of
convection, and at least a low threat of discrete cells, tornadoes
and large hail are also certainly possible. Uncertainty is on when
and where the highest severe threat will be.

The aforementioned strong winds mixing down will bring wind gusts up
to 40-45 mph even outside of storms. Odds of widespread areas Wind
Advisory criteria are borderline, but would rather err on side of
caution, especially with some recovery efforts ongoing from last
Friday`s tornadoes. Will go with a Wind Advisory from 12Z-00Z.

Highs on Wednesday will be in the 70s, even with clouds and rounds
of storms.

&&

.Long Term...(Wednesday night through Tuesday)
Issued at 252 PM EDT Tue Apr 4 2023

Mostly quiet weather is likely for much of the long term period. The
system that will bring another round of severe weather in the short
term moves east Wednesday night. Lingering scattered showers and
storms are possible across southeast portions of the area. These
should quickly diminish overnight with increasing subsidence. Cold
air advection behind the system will aid in surface high pressure
development and keep weather conditions quiet through much of the
weekend. The high should move east of the area by daybreak Sunday
with return flow helping to warm temperatures and advect some
moisture northward. Make sure to get out and enjoy the nice weather
late this week and into the holiday weekend. Look for mostly sunny
skies with highs in the 60s, approaching 70F by Sunday.

A weak front moving through late Sunday night into Monday may bring
a chance for some light precipitation. A separate high pressure
system across the south should keep gulf moisture cutoff. With
limited moisture return and subtle forcing, confidence in
precipitation chances are low. In addition, there is a large spread
between models which is expected with weak disturbances like this.

Expect near normal temperatures early in the period before
temperatures warm up into early next week.

&&

.Aviation...(00Z TAF Issuance)
Issued at 656 PM EDT Tue Apr 4 2023

Impacts:

* Low level wind shear tonight, gusty surface winds tonight/Wed

* Peak gusts over 40kts possible Wednesday, potentially higher in
  convection

* Primary threats for convection now focused late morning and
  afternoon Wednesday

Discussion:

Warm front and the MVFR ceilings from earlier today has shifted
north with central Indiana firmly in the warm sector. S/SE winds had
become gusty with peak winds around 30kts. VFR ceilings were present
and will persist through tonight as strong southerly flow continues.
With the arrival of a strong 850mb jet overnight...low level wind
shear will become a factor late tonight persisting through Wednesday
morning.

Recent trends have suggested some changes in expectations for
convective impacts at the terminals tonight into Wednesday morning.
ACARS and LAPS soundings show the presence of a strong capping
inversion that will essentially place the lid on any potential
convection most likely through daybreak Wednesday. Cannot rule out a
few showers overnight but not expecting any impacts to terminals.
The lack of any convection late tonight and early Wednesday morning
will increase the risks for severe storms on Wednesday across
central Indiana as the airmass will largely remain untapped.

By late morning into the early afternoon Wednesday however ahead of
the front...the cap will diminish with the airmass increasingly
favorable for severe weather through the afternoon. With still
details to be ironed out...will carry broad VCTS mentions at all
terminals beginning 15-16Z and persisting through late afternoon.
Potential is there for storms to have large hail and wind gusts in
excess of 50kts. Outside of the storms...gradient winds will
intensify and peak at 40kts or greater. Convection will be east of
the terminals by early evening with winds veer from southerly to
W/SW behind the frontal passage. Gusts will also drop off into
Wednesday evening.


&&

.IND WATCHES/WARNINGS/ADVISORIES...
Wind Advisory from 8 AM to 8 PM EDT Wednesday for INZ021-028>031-
035>049-051>057-060>065-067>072.

&&

$$

Update...Updike
Short Term...50
Long Term...Melo
Aviation...Ryan



Area Forecast Discussion...Updated Aviation

National Weather Service Saint Louis MO

 920 PM CDT Tue Apr 4 2023

.UPDATE...
Issued at 911 PM CDT Tue Apr 4 2023

Just expanded the wind advisory to include the northern two thirds
of the CWA.  Have got some recent reports of wind damage over
Warren and Lincoln counties in the wake of some showers that have
mixed down some of the 60+ kt low level jet winds. Outside of
these showers, expect to see winds gust into the 40-50 mph range
outside of thunderstorms the rest of the night.

Britt

&&

.SHORT TERM...  (Through Late Wednesday Night)
Issued at 247 PM CDT Tue Apr 4 2023

Key Messages:

1) Multiple rounds of isolated to scattered thunderstorms are
possible between late this afternoon and early tomorrow afternoon,
and some of these storms may become severe. However...

2)...The timing and coverage of thunderstorms remain somewhat
uncertain. While the potential for higher end hazards - including
large hail, strong winds, and tornadoes - will be higher with storms
during the afternoon through late evening, these storms are
likely to be more isolated and may not occur locally at all. More
widespread thunderstorms are expected very late tonight through
tomorrow morning, but these storms are less likely to be severe.

3) Redeveloping thunderstorms are likely early tomorrow afternoon in
southeast Missouri and southwest Illinois along a cold front, and a
few of these may be strong or severe.

4) Gusty winds will persist through the night, with gusts to 45 mph
possible. A Wind Advisory remains in effect for central and
northeast Missouri.

All eyes are now fixed on the potential for strong or severe
thunderstorms between this afternoon and early tomorrow afternoon as
a dynamic upper level trough approaches the area from the west.
While the core of a 90+kt southwesterly 500mb jet remains well to
the west across the central plains, strong 500mb winds of 45 to 55
kt have already spread across the region, and these winds are
expected to steadily increase over the next several hours as the
trough inches eastward. Meanwhile, a deepening surface low is in the
process of sliding northeast and into Iowa, as evidence by recent
pressure falls recorded on surface observations. Low level wind
fields are expected to respond in kind, and by early evening a 60 to
70 kt low level jet is expected to develop across much of Missouri
and southern Illinois. All of this is to say that 0-6km bulk shear
will steadily increase through the day and into the evening hours,
and will be more than sufficient to support rotating updrafts. While
lower level shear is not currently particularly strong as of 19Z,
this will change quickly during the late afternoon and evening as
the low level jet strengthens.

While the kinematic environment will certainly support severe
thunderstorm development, the thermodynamic environment is a bit
more uncertain...at least initially. The initial concern during the
afternoon is with respect to convective initiation. A substantial
capping inversion was noted in an 18Z sounding in Columbia, MO as
well as nearby ACARS soundings. However, temperatures have risen
very quickly across northern Missouri under almost full sun, which
has helped to erode this capping inversion. In fact, isolated storms
have already initiated across west-central Missouri as of 19Z,
indicating that the capping inversion has nearly eroded. On the
other hand, there is some question about the quality and depth of
low level moisture, particularly along and south of an advancing
warm front now draped across southern Iowa. High resolution models,
particularly the HRRR and RAP, have suggested that deep mixing and
shallower moisture will lead to high LCLs by mid to late afternoon,
but have also continued to initiate storms across northeast Missouri
by mid afternoon. So, while these warm temperatures and deep mixing
may help us break the cap, the higher storm bases may limit the
potential for tornadoes locally during the afternoon before they
move quickly northeast and into better moisture north of our area.
Still, considering the very steep mid and low level lapse rates, the
potential for very large hail and damaging wind gusts will be
possible for a brief period this afternoon in mainly northeast
Missouri and west central Illinois, and a tornado can`t be
completely ruled out.

Once these storms move northeast, a bit of a lull in activity is
expected as the low level jet begins to ramp up and temperatures
begin to cool. Meanwhile, a cold front will slowly advance eastward,
along with stronger upper forcing from the approaching trough.
During the evening hours, there is some potential that this
additional forcing could allow for a few strong/severe storms to
develop ahead of the cold front in the open warm sector, and if this
occurs, forecast soundings support the potential for supercells with
all possible hazards, including large hail, damaging wind gusts, and
tornadoes. As for the latter, rapidly increasing low level shear
and storm relative helicity (SRH of 300-500 m2/s2 by 00Z) support
the potential for strong tornadoes as well. Again though, coverage
is likely to be somewhat limited, and this potential remains
highly conditional. This would also likely be favored across
central Missouri and the Ozarks, along with southwest Illinois,
although confidence is somewhat low regarding the location of CI.

Finally, the aforementioned cold front will push through the area
during the overnight hours, likely beginning at around 8Z in
central/NE MO. Model guidance has steadily slowed the progression of
this front, meaning that it likely will not exit the area until
roughly 18-19Z tomorrow. This would likely lead to two things.
First, thunderstorms remain likely along the front as it moves east,
particularly north of I-70. However, instability will be waning by
this time of night, which may limit the higher end potential for
severe storms during this period. Still, there will remain plenty of
shear and at least sufficient instability that it can`t be ruled
out, with a few instances of large hail and damaging winds most
likely. A tornado or two can`t be ruled out either considering the
very strong dynamics that will remain in place through the night.

By sunrise, convective coverage is likely to wane, but heating
during the mid to late morning may allow for redeveloping
thunderstorms along and ahead of the front. While this may only pose
a threat for a brief period before the front moves off to the east,
we can`t rule out a few strong to severe thunderstorms across
southeast MO and southwest IL until about 2 PM or so.

Besides the potential for thunderstorms, southerly winds are
expected to become stronger as the pressure gradient increases this
evening and overnight, and a Wind Advisory remains in effect across
central and northeast Missouri until 7 AM. Gusts to 45 mph remain
possible in these areas regardless of the presence of thunderstorms.


BRC

.LONG TERM...  (Thursday through Next Tuesday)
Issued at 247 PM CDT Tue Apr 4 2023

(Thursday - Friday)

Seasonably cool and dry conditions are forecast to end the work week
as as surface ridge moves slowly across the mid-Mississippi Valley.
High temperatures Thursday afternoon are forecast to be in the mid
to upper 50s, or about 5 degrees below normal for the date.

Some frost potential exists Thursday night due to the favorable
placement of the surface ridge and likely light/variable winds. The
one caveat is that there may still be some mid/high level cloudiness
overnight, particularly in parts of southeast Missouri and southwest
Illinois. Therefore, frost may be a bit more likely further north
where there is higher confidence in more clearing and temperatures
falling at least back into the mid 30s. There is potential for these
temperatures, if not a few degrees cooler, in parts of southeast
Missouri and southwest Illinois if the cloud cover doesn`t come to
fruition. In particular, favored valleys/low lying areas of the
eastern Ozarks which are notorious cold spots would have the
potential to have a light freeze if there is a clear sky.

A moderating trend will begin on Friday, but nothing too
substantial/rapidly changing. Low-level warm air advection looks
modest, but some weak southeasterly return flow should begin by this
time so temperatures should warm back up to near normal: into the
low to mid 60s.


(Friday Night - Tuesday)

A mostly dry weather pattern is forecast to continue this weekend
into early next week as the mid/upper level pattern will be
characterized by weak, northwesterly flow. While the center of the
surface anticyclone this weekend is likely to be in the Ohio Valley,
and toward the eastern seaboard by early next week, the western edge
of the ridge axis should still have some influences through the
weekend and potentially into early next week. By early next week WPC
500-hPa height clusters all show building ridging, either over us or
just upstream. Subsidence is likely beneath and downstream of the
mid/upper level ridge axis. This pattern is favorable not only for
dry weather, but also above normal temperatures. There is a high
confidence in above normal temperatures, but exactly how warm
depends on the speed/amplitude of the aforementioned ridge axis. At
this time, it looks more likely that it crosses the mid-Mississippi
Valley mid week. Therefore, the current thinking is that the well-
above normal temperatures (upper 70s and 80s for highs) could start
as early as Tuesday, but are even more likely just beyond. For
Sunday - Monday, high temperatures are likely to range from the
low to mid 70s, with some upper 70s possible by Tuesday afternoon.

The only chance for any measurable rainfall looks to be Sunday night
into Monday. There are signs of a northwest flow shortwave moving
through the Upper Midwest with an associated cold frontal passage.
There is a lot of spread however with the track and amplitude of
this feature, and uncertainty of moisture return ahead of any cold
frontal passage. Therefore, kept PoPs in the slight chance category
for this time frame.


Gosselin

&&

.AVIATION...  (For the 00z TAFs through 00z Wednesday Evening)
Issued at 601 PM CDT Tue Apr 4 2023

One round of thunderstorms is currently exiting parts of northeast
Missouri and west-central Illinois. Subsequent rounds are possible
through the late evening and early overnight hours, but very low
confidence in coverage/timing. There is higher confidence in a
round of storms along the cold front late tonight into Wednesday
morning. These storms will move east with the frontal boundary,
reaching the central Missouri and KUIN terminals around 0900-1000
UTC, followed by the metro St. Louis sites a few hours later. Have
best confidence in higher coverage further west, so added a TEMPO
at KJEF/KCOU/KUIN for storms. After the front moves through, the
threat for showers and storms will cease, with winds veering to
the west/northwest. Strong gusts (30-40 knots) will continue
through much of the period, before beginning to wane Wednesday
afternoon.

Gosselin

&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...Wind Advisory until 7 AM CDT Wednesday for Audrain MO-Boone MO-
     Callaway MO-Cole MO-Franklin MO-Gasconade MO-Jefferson MO-
     Knox MO-Lewis MO-Lincoln MO-Marion MO-Moniteau MO-Monroe MO-
     Montgomery MO-Osage MO-Pike MO-Ralls MO-Saint Charles MO-
     Saint Louis City MO-Saint Louis MO-Shelby MO-Warren MO.

IL...Wind Advisory until 7 AM CDT Wednesday for Adams IL-Bond IL-
     Brown IL-Calhoun IL-Clinton IL-Fayette IL-Greene IL-Jersey
     IL-Macoupin IL-Madison IL-Marion IL-Monroe IL-Montgomery IL-
     Pike IL-Saint Clair IL-Washington IL.

&&

$$

WFO LSX