Area Forecast Discussion
Issued by NWS Springfield, MO

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FXUS63 KSGF 120552
AFDSGF

Area Forecast Discussion
National Weather Service Springfield MO
1252 AM CDT Tue Mar 12 2024

.KEY MESSAGES...

- Warmer this week with temperatures 10 to 15 degrees above
  normal through Thursday.

- Shower and thunderstorm chances return on Tuesday evening into
  Wednesday morning (20-40%). Highest chances (40-70%) occur
  Thursday into Friday morning. Low potential for a few strong
  to severe thunderstorms.

- Temperatures return near normal for mid-March on Friday and
  drier weather expected for the weekend.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 1231 PM CDT Mon Mar 11 2024

Weak split upper-level flow is currently centered right over our
forecast area with a ridge axis to the north and a subtle
shortwave trough axis just to the south. Just east of the trough
axis is a relatively sharp jet stream gradient in the right-
entrance region, forcing a broad 1028mb surface high pressure
system to our ESE. A tightened surface pressure gradient on the
west edge of the high is bringing mild gusty SSW`ly winds to
our area with winds current observed winds at 15-20 mph and
gusts up to 25-30 mph. The S`ly flow is continuing to bring in
warmer temperatures with highs today expected to be in the upper
60s.


Elevated fire weather conditions this afternoon:

As tradition with the backside of exiting surface high pressure
systems, dewpoints are observed to be lower than NBM guidance by
3-6 degrees. Additionally, enhanced surface heating and boundary
layer mixing has our temps overperforming the HREF mean by 1-2
degrees and winds periodically reaching 30 mph gusts. The
combination of these three factors have already dropped RH
values to the 25-35% range and are promoting elevated fire
weather conditions over the entire CWA. HREF gives a 20-40%
chance that RHs over the eastern Ozarks drop below 25%, and
given the HREF has already been cooler than observed, probs are
closer to the 30-50% range. That being said, some isolated and localized
pockets of significant fire weather thresholds could be
attained this afternoon out in the eastern Ozarks despite them
not being in the Hazardous Weather Outlook.

Lows tonight will range from 40-50F with higher temperatures
toward the KS/MO border where high clouds will begin filtering
in overnight, keeping some of that daytime heat trapped near the
surface.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
Issued at 1231 PM CDT Mon Mar 11 2024

20-40% thunderstorm chances Tues evening into Wed morning:

A low-amplitude mid- and upper-level shortwave trough will
quickly approach the area during the day Tuesday. An attendant
sfc low will develop across KS and the associated mass response
will surge moisture northward into our forecast area with 40-50F
dewpoints settling in. The greatest moisture axis will set up
right along the KS/MO border just east of a dryline. With the
increased moisture, instability also increases within this
corridor with HREF probs at 60-80% for SBCAPE and MLCAPE to be above
500 J/kg. RAP/HRRR produce 500-1000 J/kg along the KS/MO border.
With 40-60 kts of 0-6 km bulk shear moving in beneath the
shortwave, and an eroding elevated mixed layer with 7-8 C/km
mid-level lapse rates, conditions are there for at least a few
severe storms. The SPC has a marginal (1/5; 5%) risk for this
area with one inch hail and wind gusts up to 60 mph being the
main hazards. The main uncertainty is initiation of storms. CAM
guidance suggests MLCIN values at -50 to -100 J/kg, indicating
some capping in place. That paired with only subtle mid-level
forcing, displaced mainly to the north in NE MO, and weak sfc
convergence/confluence along and ahead of the dryline may keep
storms from initially forming. Indeed, all HREF CAMs keep our
area dry, whereas global models depict storms across our entire
area. This discrepancy is likely from decent isentropic upglide
forecast to be across the area, forcing rain in the
parameterized global models. So bottom line is that the threat
for surface-based storms, possibly severe, is conditional to
initiation. What`s needed is for dewpoints or temperatures to be
a degree or two higher than modeled in order for updrafts to
break through the cap. In the 7-10 PM, the threat transitions
to an elevated nature. Given the aforementioned isentropic
upglide and a forecast 30-40 kt LLJ, this seems like the best
time period for any storms to form, perhaps severe (but still
only a 20-40% chance, along and NW of I-44), but is once again
conditional on if the lift is enough.

Another marginal (1/5; 5%) risk for severe weather sets up
Wednesday along the same corridor. Warming and moistening will
continue Wednesday with highs in the upper 70s and dewpoints in
the mid-50s. At this point, a positively-tilted longwave trough
will set up over the Rockies, with a shortwave propagating NE
through KS during the day, and a jet nosing into W MO. This
setup will also be quite conditional. Better low-level moisture
and shear kinematics will be in place for all severe hazards,
but a more pronounced EML will create a stouter cap. This will
once again make the risk conditional on if enough forcing can
break the cap for storms to form. As with Tuesday night, the
threat will transition to elevated storms as the night goes on.


Highest rain chances (40-70%) occur Thurs into Fri morning:

The best chance (40-70%) for showers and thunderstorms will be
Thursday as an embedded upper-level shortwave will lift NE from
near the Gulf, upticking water vapor transport and bringing
low-level moisture levels up to the 99th percentile for mid-
March according to ECMWF ESATs. Additionally, the associated
surface low is forecast to be deeper with stronger sfc forcing
due to a sweeping cold front. Showers and storms will likely
(40-70%) develop ahead of the cold front and move through the
area Thursday evening into the overnight hours. The heaviest
rain should stay just south of the MO border where GEFS IVT is
greatest, but moderate rainfall within thunderstorms can still
be expected. Additionally, the SPC has a 15% risk for severe
storms in the TexArkana region. Our CWA is not currently in any
risk, but NBM CAPE probs at 40-60% for >1500 J/kg and the
Extreme Forecast Index between 0.6-0.7 for CAPE/Shear suggests
that another marginal (1/5; 5%) risk could placed across our
area with the next Day 3 Outlook. Much of the uncertainty comes
with timing of these features, so check back for more refined
updates.


Temperatures return near normal for mid-March over the weekend:

After the cold front moves through, relatively stable air and
dry weather will settle in with near-normal temperatures. Highs
will be around 60F and lows will be around 40F. There are very
small chances (10-15%) for rain along the southern border as
subtle shortwave systems move through the Gulf states, but for
the most part our CWA stays dry for the weekend.

Looking ahead into the longer term, the CPC has a slight to
moderate (20-40%) risk for much below normal temperatures in our
area for March 19th-21st as long range ensembles hit on a deep
trough over the eastern CONUS during that time period.

&&

.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 1250 AM CDT Tue Mar 12 2024

Gusty south to southwesterly winds will develop over the area
this morning and continue into the evening hours. Scattered
storms are expected to develop across portions of southeastern
Kansas, western and central Missouri and could affect the KSGF
and KJLN TAF sites.

&&

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

&&

$$

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


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