864
FXUS63 KSGF 292329
AFDSGF

Area Forecast Discussion
National Weather Service Springfield MO
629 PM CDT Wed May 29 2024

.KEY MESSAGES...

- Some low end rain chances this afternoon and evening(20-50%)
  over the southwest portion of the forecast area.

- Much better chance for widespread rain(60-80%) arrives Friday
  into Saturday.

- Additional rain chances (15-30%) linger through the remainder
  of the weekend with better chances of rain(30-50%) picking
  back up early next week.

&&

.SHORT TERM /THROUGH THURSDAY/...
Issued at 1259 PM CDT Wed May 29 2024

Weak summertime upper-level flow is for the most part taking
hold of the CONUS save for troughing across the Great Lakes and
Pacific NW as noted by current water vapor imagery. In between
these troughs, large-scale ridging is present across the
northern Plains. Water vapor imagery and the latest RAP analysis
indicate a very subtle shortwave impulse moving through NW OK
overtop the tail-end of a cold front/stationary boundary
currently progged across E KS, NE OK, and into N AR. A few
light showers are associated with this impulse just ahead of
the surface front, which will be the focus for 20-50% chances of
showers and thunderstorms in far SW MO today.

Highs today are still on track to reach into the lower 80s.


Low-end rain chances (20-50%) this afternoon over SW MO:

The subtle shortwave impulse will continue to overspread the
surface boundary in the extreme SW corner of MO this afternoon.
Additionally, the right entrance region of the 700 mb jet will
be situated over this region. Lift associated with these
features--along with HREF bringing this region to 250-750 J/kg
of mean MLCAPE by peak heating--will support the development of
isolated to scattered showers and thunderstorms in extreme SE KS
and SW MO. SPC (RAP) Mesoanalysis are aggressive with 500-1500
J/kg of SBCAPE which is more supportive for thunderstorms.
Nevertheless, mean flow will be near 0, so these
showers/thunderstorms will be ordinary cells that are short-
lived and slow-moving with outflow possibly triggering other
cells in the area.

These showers/thunderstorms will likely be focused along the
surface cold front, which is currently progged right along the
SW corner of MO. Therefore, the greatest chance (30-50%) for
showers and thunderstorms would be within Cherokee, Newton,
Barry, and McDonald counties. These chances will last until peak
heating ceases after sunset.


After the rain chances, partly cloudy skies overnight will take
hold with lows in the upper 50s to low 60s with lower
temperatures toward central MO, closer to the upper-level
trough.

The mid- and upper-level ridge axis will slowly make its way
over MO during the day Thursday. With weak mean flow but
sufficient instability across the Plains, at least a few MCSs
will develop in OK/KS and move eastward through Thursday
morning. There is a low-end chance (15-30%) that remnants of
these MCSs could reach into our western CWA during the day
Thursday, producing mainly scattered showers and thunderstorms
(not expected to be severe). Otherwise, highs will reach into
the upper 70s and lower 80s again.

&&

.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
Issued at 1259 PM CDT Wed May 29 2024

Widespread rain chances (60-80%) Friday into Saturday:

Multiple rounds of MCSs will move through the Plains due to
broad westerly flow over the mountains promoting lee
cyclogenesis within a modestly unstable airmass. One particular
round will be riding ahead of another subtle shortwave impulse
that will move along the KS/OK border. Medium-range CAMs suggest
that any MCS associated with this impulse will create an MCV
that will enhance the mid-level shortwave. In turn, the feedback
loop will produce a weak surface low and 850 mb low-level
cyclone. Surface fronts and a modest LLJ will be associated with
these features. As such, increased rain chances arise for Friday
(60-80%) through Saturday morning (30-50%).

Current model guidance has the warm front staying south of the
MO/AR border, which will keep any severe weather chances out of
our area. It will also keep our area rather cool with highs
Friday and Saturday in the mid to upper 70s and lows in the
lower 60s. However, strong meridional 850 mb flow will ride
over the warm front, pumping moisture up into our region. Based
on that synoptic setup, widespread rainfall and embedded
thunderstorms will be likely for much of our area through the
day. With the shortwave displaced from the longwave, and the MCV
orienting positive vorticity advection in a way that represents
an cut-off low, the wave will progress rather slowly. This will
keep rainfall over our area for an extended period of time
through Saturday morning making flooding a low- end threat. The
WPC does have portions of our CWA in a Slight (2 of 4) Risk for
excessive rainfall. However, with 75th percentile NBM QPFs only
at 1-1.5" in 48 hours, flooding is still a low-end threat at
this time. This is especially true with model spread still quite
high. The 25th-75th percentile spread is around 1-1.5", meaning
a low-end scenario has most of our CWA at 0.25-0.5" and a
higher-end scenario at 1.25-2.5". To further the uncertainty,
the NBM has the greatest axis of precipitation west of Highway
65, while the WPC guidance has widespread 1-1.5" across our
whole CWA. Greater confidence will come with a better handle on
the evolution of the wave and MCV, but the bottom line is that
most of our CWA will see at least 0.25-0.5" of rain through
Saturday morning.


Isolated rain chances (15-30%) for the rest of the weekend:

After the shortwave exits, there will be a brief dry period
Saturday night through early afternoon Sunday. At this point,
ensembles point to a summer-like pattern with the jet stream
over the northern states. Low-level flow will still be southerly
with a high pressure setting up off the Atlantic coast. This
will allow deep summertime moisture to start advecting into the
region. With temperatures increasing to the lower 80s and
dewpoints in the mid-60s, instability will be present with NBM
giving an 80-95% chance for >1000 J/kg SBCAPE. With weak upper-
level flow/forcing, pulse-like showers and thunderstorms during
peak heating Sunday afternoon appears likely, giving a 15-30%
chance for isolated to scattered short-lived showers and
thunderstorms.


Additional rain chances (30-50%) through midweek next week:

The aforementioned synoptic pattern will persist through midweek
next week, allowing moisture to continue to advect through the
region. The NAEFS and EPS ESATs have >99.5th percentile for mean
low-level specific humidity through Wednesday. This should allow
for daily isolated to scattered pulse thunderstorms, especially
if an MCV or subtle shortwave moves through. This is creating
30-50% chances for rain through midweek next week.

&&

.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 621 PM CDT Wed May 29 2024

VFR conditions through the TAF period. Scattered high clouds
across central Missouri, with some pulse thunderstorms along a
stationary front in the Arkansas Ozarks expected to remain
south of BBG (and other TAF sites) and dissipate shortly after
dark. Light southeast winds will strengthen into the daytime
hours on Thursday, and will be slightly stronger at SGF than
surrounding areas due to wind funneling effects from the
terrain. A strengthening pressure gradient will allow winds to
get slightly gusty for a few hours in the late afternoon,
especially for SGF, with sustained speeds between 10-15kts and
gusts up to 25kt. Ceilings will begin to lower Thursday
afternoon as well with the next round of precipitation moving
in.

&&

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

&&

$$

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