278
FXUS63 KSGF 232009
AFDSGF

Area Forecast Discussion
National Weather Service Springfield MO
309 PM CDT Mon Sep 23 2024

.KEY MESSAGES...

- Marginal (1 of 5) Risk for severe thunderstorms this afternoon
  and evening across the eastern Ozarks. Potential hazards will
  be damaging wind gusts up to 60 mph, large hail up to the size
  of quarters. There is a very low chance of a tornado east of a
  Gainesville to Salem line.

- Rainfall is likely this afternoon through this evening (60-90%
  chance). Most locations will see an additional 0.10 to 0.50
  inch of rainfall through tonight, with localized amounts of 1
  to 2 inches east of Springfield.

- Much cooler temperatures will occur this week with highs in
  the 70s.

- Rainfall chances (50-80%) continue to increase for late in
  the week as confidence increases on track of the next system.
  There is the potential for widespread and prolonged rainfall
  with this system by Friday and Saturday.

&&

.SHORT TERM /THROUGH TUESDAY NIGHT/...
Issued at 218 PM CDT Mon Sep 23 2024

Current Conditions and Synoptic Pattern: Water vapor and upper
air analysis continues to show a slow moving shortwave across
Iowa into Kansas. Surface low pressure was located near West
Plains with a trailing front. An area of showers has developed
across southwest Missouri behind the main front in an area of
increased lift as the upper level jet noses into the area.
Clouds have kept temps down into the 60s to lower 70s with the
exception of south central Missouri where temps have increased
into the upper 70s. This is also where a pocket of 1000j/kg of
ML CAPE exists. We are currently in a lull of bulk shear
however a mid level speed max was moving up the Red River and
will likely increase bulk shear to 40kts by later this
afternoon.

This afternoon and evening: Lift will continue to increase and
expect a gradual uptick in showers and thunderstorms, especially
along and east of Highway 65 this afternoon, lasting through
late evening. Areas along and east of a Branson to Salem line
are in a marginal severe risk as this area is overlapped with ML
CAPE around 1000j/kg and increasing shear. A few multicells and
perhaps even some low topped supercells look to form late this
afternoon and evening. Latest RAP sounding for Oregon county
around 4-6pm shows the potential for around 1500j/kg of ML CAPE<
35-40kts effective shear which would be enough for a few severe
storms with large hail up to the size of quarters (if the
supercell threat was higher then the expected hail size would
need to be increased) and damaging winds up to 60 mph. There is
a low tornado risk briefly as the low passes with southeast
winds however this window looks brief with surface winds quickly
becoming southwesterly. Hodographs mainly look long and
straight which could promote a few splitting cells. The window
for severe storms is mainly from 3pm-9pm.

PW values of 1.5-1.6in will continue to promote heavy rainfall
rates. Latest HREF data suggests pockets around 0.5inch with
localized areas seeing 1-2 inches east of Highway 65. This could
produce a localized flash flood threat this evening. Most of the
heavier rainfall will have ended by 9pm however scattered
showers will likely continue across the eastern Ozarks through
the overnight hours as the shortwave trough moves through.
Locations further west will likely have low clouds and patchy
fog. Low temperatures will likely reach the upper 50s west of
Springfield.

Tuesday: Additional shortwave energy looks to drop down into the
area during the day which will promote clouds and cool temps
with northerly winds. Seeing a signal in short term guidance
that drizzle or light rain showers will occur across areas
northeast of Springfield during the day. If confidence increases
in this scenario then precip chances will need to be increased
(even though amounts would be very light). High temps in the 70s
are likely with the coolest readings (perhaps upper 60s), across
the northeast CWA.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
Issued at 218 PM CDT Mon Sep 23 2024

An unsettled stretch is shaping up during the late week into the
weekend as an upper low drops south into Missouri and
potentially interacts with the developing Potential Tropical
Cyclone Nine. Guidance has come into decent agreement that the
upper low will move south over Missouri on Wednesday. There is a
10-20% chance of rain east of Springfield during the afternoon
however not expecting widespread rain.

The track of the tropical system will be key from Thursday into
the weekend as ensembles still continue to struggle with its
exact track through the southeast US. Ensemble clusters all
support rain across the area Thursday and Friday, especially
given the lift from the upper low and increasing moisture. It
should be noted that the multi modal mean in the ensemble
clusters shows the potential for over 2 inches of rainfall.
ECMWF extreme forecast index/shift of tails also shows the
potential for an anomalous rainfall event across the eastern
half of the area. Lastly, the latest NBM is showing greater than
a 60 percent chance of at least 3 inches of rainfall Thursday
through Saturday. With all this said, confidence is increasing
that a period of prolonged excessive rainfall is increasing
somewhere across the region, with increasing signals for the
eastern half of the area being in this zone. This will all be
dependent on the track of the tropical system and its
interaction with the upper low therefore stay up on the forecast
through the week. Temperatures will likely remain below average
through the week and into next week with precip and north
winds.


&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 1227 PM CDT Mon Sep 23 2024

Showers and thunderstorms will likely develop and move through
the sites this afternoon with chances decreasing after 7pm.
Flight conditions are already IFR at JLN and will likely
continue there through the afternoon with MVFR conditions at JLN
and BBG. Patchy fog also looks to reduce vis into MVFR at times
overnight. Winds will be variable this afternoon with a gradual
switch to the west by this evening. Flight conditions will
likely improve back towards VFR by the end of the period.

&&

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

&&

$$

SHORT TERM...Burchfield
LONG TERM...Burchfield
AVIATION...Burchfield