-- Discussion containing changed information from previous version are highlighted. --
111
FXUS63 KSGF 161733
AFDSGF

Area Forecast Discussion
National Weather Service Springfield MO
1233 PM CDT Sun Jun 16 2024

.KEY MESSAGES...

-  Heat and humidity will continue through Monday then return
   late next week.

-  Daily chances for isolated showers and thunderstorms (15-30%)
   thanks to the hot and humid air mass.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 400 AM CDT Sun Jun 16 2024

Current water vapor imagery depicts synoptic-scale clockwise
flow over the eastern CONUS centered around AL/GA. Coinciding
with radar observations, an MCS is currently progressing through
NE KS/NW MO ahead of a weak shortwave trough within the
inflection point between the longwave ridge in the east and
longwave trough over the NW CONUS. Within this inflection point,
across the Plains, a 30-50 kt low-level jet is present. At the
surface, a NW-SE oriented boundary is draped across east MO,
just outside our area. This is keeping temperatures just
slightly warmer across our CWA, with lows this morning on track
to be in the lower 70s.


Heat and humidity will continue through Monday:

The aforementioned subtle shortwave trough will erode through
today as it lifts just north of our area, allowing the
developing upper-level high to build in from the east.
Additionally, 850 mb temperatures will be allowed to modestly
rise to the 19-21 C range. Aided by generally clear skies, these
factors will promote high temperatures today in the lower 90s.
Dewpoints will also continue to be in the lower 70s, upping max
Heat Indices to 95-100 F. Lows will then be mild in the lower to
mid-70s.

The large-scale synoptic pattern will remain relatively
unchanged into Monday, which will keep highs around the same as
today (lower 90s). Heat Indices will then also be in the 95-100
F range as dewpoints continue to hover in the lower 70s. Therefore,
continue to exercise proper heat safety both today and Monday
by taking frequent breaks, having cooling methods available,
and keeping hydrated.

Daily chances for isolated showers and thunderstorms (15-40%):

There is a very low chance (<15%) that an isolated shower and
thunderstorm or two could develop this afternoon with the
exiting trough within our warm, moist, and (relatively) uncapped
airmass east of Hwy 65. However, dry mid-level air associated
with the eroding trough will be entering the region.
Additionally, subtle subsidence inversions have been noted on
past observed soundings which likely kept storms from developing
the last couple days. Therefore, confidence is quite low in
shower/thunderstorm formation. But weirder things have happened.

Chances for showers and thunderstorms increase to 15-40% Monday.
Despite the large-scale synoptic setup remaining largely
unchanged, a subtle mesoscale/tropical disturbance exiting the
Gulf will enter AR and SE MO, bringing in deeper low-level
moisture profiles with it (>97.5th percentile mean specific
humidity and 1.5-1.75" PWATs). Positive vorticity advection
associated with this disturbance should actually provide enough
lift for isolated showers and thunderstorms this time around.
Ensemble models are still in disagreement on coverage, however,
with HREF PoPs <15%, NBM and CONS at 15-40%, and SREF at 40-70%.
Therefore, will currently advertise 15-40% PoPs east of Hwy 65,
with greater chances toward south-central MO, closer to where
the axis of greater moisture will be. With a tropical origin for
this weak system, brief, heavy downpours and lightning will be
the main hazards. Severe weather is not expected with these
showers and thunderstorms.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
Issued at 400 AM CDT Sun Jun 16 2024

Daily chances for isolated showers and thunderstorms (15-30%):

The synoptic pattern after Monday will put our region in an area
of weak upper-level flow with an upper-level high over the
Carolinas, longwave troughing over the western CONUS, and an
inverted trough associated with a tropical disturbance along
the Gulf Coast in east TX. With cloud cover increasing from the
tropical disturbances, and multiple rounds of rain across the
Gulf Coast cooling air that gets advected into our region, we`ll
see a slight "cooldown" Tuesday and Wednesday with highs in the
middle to upper 80s and lows in the upper 60s. The air will
still be moist and feel hot with dewpoints in the upper 60s
contributing to max Heat Indices in the lower 90s.

Deep moisture will continue to increase into Tuesday as PVA
associated with subtle disturbances continue to rise up out of
the Gulf. PWATs Tuesday will increase to 1.75-2" in the eastern
Ozarks (97.5th percentile of the 30-year climatology for this
time of year). As such, showers and thunderstorms could develop
in this region again along the ribbon of positive vorticity
advection (east of Hwy 65). Chances are lower a tad lower at
15-30% due to the lack of a distinct disturbance to move through
Tuesday.

Another disturbance will lift into SE MO Wednesday.
Additionally, a front is forecast to stall over KS/north MO.
These two lifting mechanisms could promote enough lift for more
isolated showers and thunderstorms across our whole CWA (15-25%
chances). Confidence is lower this day as the upper-level high
across the east coast is forecast to start building westward,
which could inhibit updrafts.

Rain chances will then dwindle as the upper-level high builds
in. The next chances come next weekend as global models hint at
remnants of a tropical system rounding the southern edge of the
upper-level high and entering our area. Confidence is still
quite low on this scenario, though, leaving chances at 15-30%
Sunday.


Heat and humidity return late week:

Into Thursday, the high pressure really starts to build west.
Low-level flow will also transition to ESE`ly. Increased ridging
over our area will allow heat to rebuild, and force rain to
vacate the region (generally <15-20%). Highs are forecasted to
enter the 90-95 F range again through the end of the period.
Highs Thursday will be in the lower 90s with lows around 70 F
except for in the eastern Ozarks. The NBM ensemble spreads
indicate that highs could even reach above 95 F in the following
days, especially into Saturday. Exact details still need to be
ironed out, but expected a rebound of heat in the late week.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
-- Changed Discussion --
Issued at 1227 PM CDT Sun Jun 16 2024

Pop-up thunderstorms have formed near the MO/AR border and will
continue to develop generally along and east of highway 65. Main
threats are lightning and brief heavy downpours. Convection will
continue for the next few hours before skies clear out this
evening. Have added a TEMPO group to SGF and BBG to reflect
this.
-- End Changed Discussion --

&&

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

&&

$$

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