131
FXUS63 KSGF 111935
AFDSGF

Area Forecast Discussion
National Weather Service Springfield MO
235 PM CDT Thu Jul 11 2024

.KEY MESSAGES...

- Scattered showers and thunderstorms into Friday. A few storms
  may produce wind gusts up to 60 mph and hail to the size of
  quarters into this evening.

- Heat indices climb into the 100-107 degree range from Sunday
  through Wednesday.

- A cold front will bring the potential for more thunderstorms
  to the region next Wednesday or Thursday along with cooler
  temperatures.

&&

.SHORT TERM /THROUGH FRIDAY/...
Issued at 154 PM CDT Thu Jul 11 2024

Synoptic Scale Pattern and Current Conditions:

Water vapor imagery depicts a short wave trough diving southeast
across the Great Lakes with a secondary lobe of vorticity
dropping south across the Corn Belt. At the surface, a front has
stalled out in the vicinity of the I-70 corridor from northeast
Kansas into Missouri. An outflow boundary from morning storms
is dropping south through central Missouri and is becoming more
diffuse with time.

A loose cluster of showers and thunderstorms that persisted for
much of the morning, has now almost vanished in the vicinity of
Rolla and Dixon. Sky conditions as of 2 PM range from mostly
sunny to partly cloudy. Temperatures over most areas have warmed
into the middle 80s to lower 90s. A few locations across
central Missouri remain in the lower 80s due to slightly greater
cloud coverage.

Thunderstorm Potential through Mid-Evening:

Upper level ascent will increase as that short wave trough in
the Corn Belt moves into northern Missouri. In addition to the
upper level ascent, surface temperatures will near convective
temperatures which are in the upper 80s to lower 90s per the 12Z
KSGF RAOB as well as short term RAP initializations. These
factors along with weak convergence along that outflow boundary
will result in widely scattered thunderstorm development into
early this evening.

MLCAPE values ahead of the outflow boundary will be in the
1500-2500 J/kg range with deep layer shear of 25-30 knots.
This will be supportive of a few storms potentially reaching
marginally severe levels. Hail to the size of quarters and
damaging wind gusts to 60 mph will be the primary potential
severe weather hazards.

Low temperatures tonight will range from the middle 60s across
the eastern Ozarks to the lower 70s around Joplin and Neosho.

Thunderstorm Potential from Late Tonight into Friday Morning:

That surface front will remain stalled somewhere near or just
south of I-70. Meanwhile, short term models are in good
agreement that a low-level jet will develop and strengthen
across Oklahoma and eastern Kansas starting late this evening.
This feature will then veer into far western Missouri starting
late tonight.

Lifting parcels from planes in the 850-750 mb layer yields
800-1600 J/kg of CAPE with little in the way of inhibition. We
therefore think that isentropic upglide will initiate widely
scattered elevated thunderstorms across western and central
Missouri after midnight. This activity will then slowly work
east across the Missouri Ozarks through Friday morning.

The main potential hazards with overnight and Friday morning
activity will be hail to the size of pennies and perhaps wind
gusts to 50 mph if wind can penetrate the nocturnal inversion.

Friday Afternoon and Friday Night:

Morning activity may very well survive into the afternoon as it
pushes into the eastern Ozarks. Otherwise, a few pop-up storms
will be possible (20- 30% chances) primarily across the eastern
Ozarks during peak heating. A capping inversion may limit, or
completely eliminate any potential for convective development in
the afternoon along and west of the Highway 65 corridor.

The experimental Ozarks Pulse Severe Thunderstorm Index
indicates that any storms that form across the eastern Ozarks
Friday afternoon will have the potential to produce damaging
downbursts and perhaps hail to the size of quarters. Until we
can get a better feel for thunderstorm potential Friday
afternoon, we are going to continue adverting wind gusts to 50
mph and hail to the size of pennies as the primary convective
hazards across the eastern Ozarks. Wind gust and hail size
values may need to be nudged upward in future forecasts.

A slow warming trend will continue into Friday as a ridge over
the western U.S. slowly continues to build east. The NBM shows
tight clustering with high temperatures on Friday. Thus,
confidence is high that temperatures will range from the middle
and upper 80s across the eastern Ozarks to the lower and middle
90s along the I-49 corridor.

&&

.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
Issued at 154 PM CDT Thu Jul 11 2024

Friday Night into Saturday:

That warm front will lift north as the upper level ridge
continues to build east. Most ensemble members keep the Ozarks
dry for this period with thunderstorm activity well north and
east of the area closer to that lifting warm front.

One alternative scenario depicted by some short term ensembles
is the development of elevated convection and potentially even
an MCS across northern Missouri from late Friday night into
Saturday morning. If the MCS scenario were to materialize, wind
fields would support the MCS dropping south into central
Missouri and the eastern Ozarks.

If we remain dry with little in the way of cloud cover (the most
likely scenario) on Saturday, we will have no problem
continuing our warming trend with most areas warming into the
lower and middle 90s. If the MCS scenario does indeed come to
fruition, we would see slightly cooler temperatures due to the
precipitation and cloud cover.

Sunday into Tuesday:

Global ensembles show strong agreement that the upper level
ridge will continue to build east into the area. Dry weather
and hot conditions will be the result. Highs by Monday and
Tuesday will be in the middle 90s to around 100 degrees with the
warmest readings along the I-49 corridor. Confidence is high in
these temperatures given that the NBM statistical data only has
2-4 degree spreads between its 25th and 75th percentiles.

We are still expecting afternoon heat indices of 100-107
degrees early next week as dew points remain in the middle 60s
to lower 70s. Heat headlines will correspondingly be in play.

Wednesday and Thursday:

Global ensembles continue to depict a large amplitude upper
level trough diving southeast through Hudson Bay and the Great
Lakes. We are becoming increasingly confident that this trough
will drive a cold front south either into or through the
Missouri Ozarks. This is supported by the vast majority of
global ensemble members.

The passing front will bring us our next shot at showers and
thunderstorms along with a return to near or slightly below
normal temperatures.

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1125 AM CDT Thu Jul 11 2024

VFR conditions will prevail for much of the period. Isolated
thunderstorms are expected from late this afternoon into early
this evening. Given the limited coverage, we have opted not to
include any mention of thunderstorms in the TAFs through early
evening. Amendments will be required if the threat for a
thunderstorm increases at any of the aerodromes.

Widely scattered thunderstorms are then expected from late
tonight into Friday morning as a low-level jet stream noses into
western Missouri. We have therefore included PROB30 groups for
thunderstorms at both Joplin and Springfield. Most activity is
expected to remain north of Branson.

Brief IFR visibilities can be expected with thunderstorms along
with gusty and erratic winds. Outside of thunderstorms, surface
winds will remain light out of the south to southeast through
Friday.

&&

.CLIMATE...
Issued at 154 PM CDT Thu Jul 11 2024

Record High Minimum Temperatures:

July 15:
KSGF: 79/1954

July 16:
KSGF: 81/1914

July 17:
KSGF: 79/1934

&&

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

&&

$$

SHORT TERM...Schaumann
LONG TERM...Schaumann
AVIATION...Schaumann
CLIMATE...Schaumann