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000
FXUS63 KSGF 092003
AFDSGF

Area Forecast Discussion
National Weather Service Springfield MO
303 PM CDT Tue Apr 9 2024

.KEY MESSAGES...

- Increasing rain chances late tonight into Wednesday morning.
  Highest rainfall chances and amounts focused along and south
  of Interstate 44 through Thursday morning. Low potential for
  excessive rainfall and minor flooding across south central
  Missouri. No severe weather expected.

- Elevated to significant fire weather potential Thursday
  through Saturday. Highest potential on Thursday with gusty
  northwest winds and low humidities.

- High confidence in drier weather and above normal temperatures
  this weekend with highs in the 70s to potentially the mid-80s.

&&

.SHORT TERM /THROUGH WEDNESDAY NIGHT/...
Issued at 1251 PM CDT Tue Apr 9 2024

A broad 60-100 kt upper-level jet is currently overspread across
the entire eastern CONUS bringing SW`ly flow across the region.
An upper-level low is situated north of Lake Superior and
another is slowly digging into west TX. At the surface, a
quasi-stationary boundary is oriented along, but just SE of,
I-44. This boundary looks to have a vertical persistence
through about 700 mb. WSW`ly flow is overtop the boundary at 500
mb and above. SE of the surface boundary, dewpoints are
reaching into the 55-60 F range and NW of the boundary dewpoints
are in the lower 40s. Across the whole region, highs are in the
upper 60s, approaching 70. To the south in the ArkLaTex region,
strong low- level warm air and moisture advection have been
forcing widespread storms and rain. This will continue until the
upper- level wave kicks progresses through the region and kicks
the system north and eastward.


Increasing rain chances late tonight through Wednesday night:

TL;DR:

There is a 20-40% chance of scattered showers and perhaps a
rumble of thunder or two late this afternoon along a line from
Cassville to Salem. Once the sun sets, chances for rain dwindle
until late tonight and early Wednesday morning. Widespread
precipitation, especially along and SE of I-44 could start
anywhere from 4-9 AM. Generally amounts are between 1-2" along
and SE of I-44 and between 0.25-1" SE of a Versailles to
Pittsburgh line. Much of the precipitation will be north of
boundaries as a precipitation shield, so severe weather is not
expected, but a rumble of thunder or two cannot be ruled out.
Additionally, highs will be cool in the upper 50s to lower 60s
and lows in lower 50s Tuesday night and mid-40s Wednesday night.

All the details:

Along and SE of the quasi-stationary boundary, cumulus and
stratus/altostratus clouds are developing. Latest RAP output
depicts 100-250 J/kg of weakly capped MLCAPE in this region.
Latest HRRR/RAP runs have scattered showers/thundershowers
develop along the boundary at peak heating around 4-7 PM. These
would be in a line parallel to I-44, generally along a Salem to
Cassville line. Given the presence of instability, these will
bring the chance (10-20% chance) of a rumble of thunder or two,
but mainly these would consist of scattered showers (20-40%
chance).

After this initial band of showers, there will be a lull in rain
chances before they increase late tonight once the upper-level
wave approaches. PoPs are still set at 20-30% for much of the
night as isolated showers can`t be ruled out, but the more
widespread rain chances begin early Wednesday morning. As the
wave approaches, mid-level positive vorticity advection,
850-700 mb WAA, and associated isentropic upglide will
overspread the region leading to widespread precipitation,
especially along and SE of I-44. This looks to begin anywhere
within the 4-9 AM timeframe. Unfortunately, CAMs have been
unhelpful with the timing of onset of this widespread
precipitation. Run-to-run and model-to-model have shown widely
varying solutions, likely because of the complex mesoscale
evolutions of the weakly forced storms in east TX. Once
precipitation starts, however, it will likely (70-90% chance)
stay persistent through late Wednesday night with only brief
pauses, especially the further southeast of I-44 you are
located.

Despite uncertainty in timing, confidence in location and
amounts is somewhat increasing. Latest WPC and model cluster
guidance places the axis of >0.25" of rain along and SE of a
line from Versailles to Pittsburgh with all of our CWA within
the >0.05" axis. This is a more NW shift from the previous
forecast. Additionally, guidance seems persistent in placing the
0.5-1" range along I-44, including Springfield, Joplin, and
Rolla. Amounts begin to vary SE of I-44 where GEFS-weighted
clusters bring near 3 inches in this region while EPS-weighted
clusters bring only 1-1.5" in this region. HREF CAMs clock in
at 1.25-1.75" SE of a line from Branson to Salem. Even with
CAMs and other global ensembles favoring the lower-end scenario,
there is still a low-end chance for excessive rainfall and minor
flooding across south-central Missouri. Indeed, the WPC has a
marginal (1/4) risk for excessive rainfall in this region.

With the surface low passing south of our area, the
precipitation will be part of the backside precipitation shield
north of any boundaries. As such, little instability will reach
into our region and no severe weather is expected. However,
embedded thunderstorms within the precipitation shield are
still possible (15-40% chance). Additionally, with the low
passing to the south, temperatures will decrease with highs
Wednesday in the upper 50s and lows Tuesday night in the lower
50s and the mid-40s Wednesday night. The system then looks to
exit late Wednesday night and early Thursday morning.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
Issued at 1251 PM CDT Tue Apr 9 2024

Elevated to significant fire weather potential late week:

After the system clears through Thursday morning, cooler, drier,
and gustier air will filter into the region. Highs Thursday only
look to reach into the lower 60s with lows in the lower 40s.
Additionally, relative humidities will drop into the 30-50%
range with lower values along the MO/KS border. The deepening
surface low that`s exiting will tighten its backside surface
pressure gradient and increase NW`ly winds to 20-25 mph with
gusts up to 30-40 mph. Current NBM probs give a 60-80% chance
for >45 mph gusts NW of I-44 close to the MO/KS border which
would be Wind Advisory criteria. However, the NBM has been
consistently downtrending on wind speeds in recent forecasts and
will likely continue once CAMs are weighted into it. So for
now, max gusts are advertised between 30 and 40 mph.

Either way, the gusty winds and dry air will create elevated to
significant fire weather danger Thursday. For now, Thursday is
holds the greatest fire weather risk as winds will be strongest
then, but the dry air will remain in place through Saturday
which will promote elevated to significant fire danger through
then.


High confidence in above normal temperatures this weekend:

After Thursday, a gradual warming trend will commence as deep
and broad upper-level region moves into the central CONUS. Warm
air will really get going once a surface high departs and
S`ly flow brings in warm and moist gulf air. Highs Friday will
be in the upper 60s, then highs Saturday will be in the upper
70s, pushing 80. Sunday and Monday look to be the warmest days
of the series with highs in the lower to mid-80s. During this
period, lows will also slowly climb from the mid-40s Friday
night to around 60 F Saturday night through Monday night.

The next system then arrives sometime early next week. Details
are still to far out to nail down best timing and type of
precipitation (rain, thunderstorms, etc.), but ensembles depict
14-18C 850 mb temps reaching all the way up to the US/Canada
border in MN/ND, which means a large warm/moist sector will be
in place for the potential of thunderstorms. Later forecasts
will begin to address this, especially after the more imminent
system has cleared the area.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1239 PM CDT Tue Apr 9 2024

Low- to mid-level clouds are pushing into SGF and BBG from the
east and will continue in coverage through the evening,
gradually lowering ceilings. MVFR conditions are expected at all
TAF sites by 09Z with BBG receiving them earlier in the 03-06Z
timeframe. BBG`s ceilings may drop to IFR after 06Z.

Showers and thundershowers are possible at all TAF sites
overnight tonight. Timing and location is still very uncertain
with run-to-run models varying widely. As such, many different
TEMPO/PROB30 lines are in the TAFs. The best chance for
widespread rain and thundershowers will be between the 09-12Z
timeframe. All other times will see vicinity showers and perhaps
a quick light shower or two.

Otherwise, winds will generally be light out of the east at 5-10
kts.

&&

.SGF WATCHES/WARNINGS/ADVISORIES...
KS...None.
MO...None.

&&

$$

SHORT TERM...Price
LONG TERM...Price
AVIATION...Price