122
FXUS63 KSGF 070930
AFDSGF

Area Forecast Discussion
National Weather Service Springfield MO
330 AM CST Thu Nov 7 2024

.KEY MESSAGES...

- Patchy fog again this morning, mainly along and north of the
  Ozark Plateau.

- Residual river flooding will continue today with all river
  points forecast to drop below Minor Flood Stage by the day`s
  end.

- High probability (80-95%) for widespread rain with another
  system moving through late Friday and Saturday. Rainfall
  amounts from 0.50" to 1.00". Localized amounts around 2.00" in
  south-central Missouri, and along and west of the I-49
  corridor.

- Additional potential (30-50%) for showers and thunderstorms
  next Tuesday night and Wednesday.

&&

.SHORT TERM /THROUGH FRIDAY/...
Issued at 330 AM CST Thu Nov 7 2024

Current satellite imagery paired with RAP analysis depicts broad
SW`ly flow across the central and east CONUS with a shortwave
traversing the northern Great Lakes, and a cut-off mid- and
upper-level low over the Four Corners Region. At the surface, a
potent surface system associated with the upper-level low is
continuing to mature along the Rocky Mountain Front Range.
Additionally, a stationary boundary remains rooted beneath the
SW`ly flow aloft, stretching from New England down into east
TX.


Patchy fog again this morning:

The position of the stationary boundary can easily be seen on
Nighttime Fog/Stratus satellite imagery with northward
propagating low clouds positioned on the cool (north) side of
the boundary as moist 925/850 mb S`ly flow moves overtop the
surface boundary. This cloud deck is stretching into south-
central MO where it is colliding with a southwestward advancing
low cloud deck developing due to N`ly upslope flow along the
Ozark Plateau. Additionally, satellite and surface obs depict
patchy fog and fluctuating visibilities where dewpoint
depressions are lowest (pretty much our whole forecast area).
The cloud decks and mild winds should keep fog from being
particularly dense this morning. However, expect areas of
patchy fog until a couple hours after sunrise this morning,
especially in low-lying areas where temperatures are coolest.
Low morning temperatures will be in the 40s (higher values
toward the southern border). After the clouds and fog burn off,
highs will reach the upper 50s to lower 60s.

The same sort of setup is expected again tonight into Friday
morning, making patchy fog and low clouds possible. Lows tonight
will drop into the upper 30s in the eastern Ozarks, to the
middle 40s along the southern border. Highs Friday will then be
slightly warmer in the lower 60s.


River flooding will gradually decrease today:

River flooding will continue to recede today, with river point
forecasts all expected to drop below Minor Flood Stage by the
end of today. Nevertheless, other creeks and streams at certain
low-water crossings still have roads closed east of Springfield,
according to MODOT. Therefore, despite receding water levels,
continue to exercise caution when driving near creeks and
streams, and check MODOT`s traveler map for updated road
closures. If you do encounter water over the road, remember,
Turn Around, Don`t Drown!


&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Issued at 330 AM CST Thu Nov 7 2024

Temperatures are expected to stay pretty constant through the
long term period. Highs will consistently be in the middle 60s,
with near 70 F temperatures Monday and Tuesday. Lows will
consistently be in the middle to upper 40s, with lower 50s
Tuesday night.


80-95% chance for rain late Friday night and Saturday:

The cut-off low will make a typical lollygag to the east over
the course of today and Friday. It will start to translate NE
through the area Friday night and Saturday. The ejection will
finally kick the surface low over the Rockies out into the
Central Plains. Both the deep cut-off low, and deepening surface
cyclone system will force a widespread rain shield across the
Southern Plains that will lift NE through our area Friday night
through Saturday evening (80-95% chance of rain throughout the
CWA).

Medium range model guidance suggests that the warm front will
stay south of our area, with only the occluded front passing
through Missouri. This should keep much of the activity as
stratiform rain. However, 03Z SREF puts mean MUCAPE values at
100-200 J/kg across our forecast area. This would be just
enough for some isolated embedded thunderstorms within the rain
shield, but not enough for any severe threat.

As for rainfall amounts, mean model output has been rather
consistent on widespread 0.5-1.00" across the forecast area.
Although the NBM mean has bands of 1.00", suggesting around a
50% chance for >1.00", the latest SREF guidance signals that
amounts may be somewhat lower, with a 30-50% chance of >0.5" and
only a 10% chance of >1.00". The NBM 75th-90th percentile
depicts areas of 1.5-2.5". Thus, our forecast advertisement is
for widespread areas of 0.5-1.00" with localized values up to
1.5-2.5" where any thunderstorms or heavier mesoscale rain bands
set up.

The current guidance for the surface low track makes the best
chance for seeing locally higher amounts to be in two separate
areas. One area being along the I-49 corridor, closer to the
deepening surface low. And another area being in south-central
Missouri where the warm/cold/occluded front triple point will
track. These two features will provide extra forcing for locally
higher rainfall amounts. With the second area of focus being
over south-central Missouri, a marginal flooding threat will
need to be monitored as it will not take much rain to aggravate
already stressed river basins in that area. This is especially
true if any efficient rainmakers track over that area given
forecast 1.25-1.5" PWATs (97.5th percentile for early November
via NAEFS and ECMWF ESATs).

This system is expected to clear out by Sunday morning, bringing
a stretch of dry weather Sunday through Tuesday.


30-50% chance for showers and thunderstorms middle of next week:

As this first system exits, the next system will be entering
the west coast. Global ensembles are in agreement that a trough
will traverse the Plains sometime Tuesday night through
Wednesday night. Cluster analysis shows broad differences in
timing and intensity, however, leading to only a 30-50% chance
over a broad time range from Tuesday night through Wednesday
night. In fact, just looking at the three main deterministic
models, the GFS depicts a positively-tilted trough, the ECMWF
depicts a neutrally-tilted trough, and the Canadian depicts a
negatively-tilted trough. These would all have different
scenarios in terms of timing and intensity of the system.
Subsequent forecasts will be monitored to determine a better
time range and probability of rain, but it appears likely that
showers and thunderstorms will traverse the region sometime
midweek next week. After the system passes, signals point to
temperatures cooling with forecast lows in the 30s Wednesday
night and Thursday night, and highs Thursday in the middle 50s.


The active pattern may not be over after the middle of next week
as the CPC 8-14 day outlook favors above normal precipitation,
and has an area outlined for a slight risk of heavy
precipitation during the same period. More details to come.


&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1140 PM CST Wed Nov 6 2024

Main aviation concern this TAF period is once again the
potential for patchy fog and/or low clouds between 08-14Z,
bringing conditions down to MVFR with fluctuations into IFR,
especially at SGF and JLN. Current satellite depicts SCT to BKN
3500 ft clouds developing around BBG and in south-central MO. A
more prominent 2300 ft cloud deck is over central IL/east MO.
Thinking is that these clouds will gradually fill in along the
Ozark Plateau, impacting SGF and BBG, and possibly JLN. MVFR to
IFR low clouds is favored versus patchy fog, but cannot rule
out intermittent periods of decreased visibilities.

Afterwards, clouds will likely burn off after 14Z, though there
is some signal that low clouds will linger at least through 18Z
along the Plateau. Otherwise, winds will be at 5-10 kts out of
the ENE.

&&

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

&&

$$

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