Area Forecast Discussion
Issued by NWS Springfield, MO

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000
FXUS63 KSGF 240349
AFDSGF

Area Forecast Discussion
National Weather Service Springfield MO
949 PM CST Fri Feb 23 2018

...Update on Flooding Potential...

.MESOSCALE DISCUSSION...
Issued at 923 PM CST Fri Feb 23 2018

The setup will remain favorable overnight for flooding potential.
We have expanded the Flood Watch a bit to the north with
increasing confidence that those regions will also see heavy
rainfall.

The nose of a low level jet stream will shift northeast across
southern Missouri overnight with an increasingly large area of
isentropic upglide occurring over the top of a developing warm
frontal structure. Meanwhile, a pseudo upper level jet coupling
structure is in place across the region and aiding in deep
tropospheric ascent. This has resulted in a large swath of light
to moderate precipitation expanding across the Ozarks this
evening.

Anomalously high values of moisture also continue to advect into
the region with precipitable water values pushing 1.25" expected
to push into far southern Missouri late tonight. Short term
guidance and analysis of upstream soundings also indicates weak
upright instability now beginning to push into the region. Bursts
of heavy rainfall with embedded convective elements will therefore
become increasingly likely throughout the night. This is already
occurring across eastern Oklahoma.

At this time, inspection of RAP 850 mb moisture transport vectors
and theta-e advection indicate that the heaviest rainfall
overnight will fall in the general proximity of the I-44 corridor
(roughly along and 30 miles north/south of the interstate). We
therefore added to the northern edge of the previous Flood Watch.

Overall, 1-3" amounts are expected overnight within the
aforementioned swath. We will have to closely monitor the
progress of convective elements for the potential of localized
flash flooding overnight.

&&

.SHORT TERM...(This evening through Saturday Night)
Issued at 320 PM CST Fri Feb 23 2018

An upper level trough is currently located across the southwestern
U.S. this afternoon. The Trough will track east towards and
through the region this weekend with additional rounds for
moderate rain expected across region.

An upper level disturbance ahead of the main trough is currently
tracking northeast across the region this afternoon. An area of
rainfall has developed across Oklahoma and Arkansas and is
begnning to spread north into southern Missouri and southeastern
Kansas late this afternoon. The rain will continue to spread
north into the area into the overnight hours. The heaviest
rainfall will general occur along and south of I-44. A few storms
will be possible tonight as instability starts to slightly
increase across southern Missouri. No severe weather is expected
through tonight. The bulk of the rainfall should spread east of
the area by Saturday morning, though there could be some drizzle
or a rouge shower around in the morning but all in all there
should be a brief break in the rain.

Lows tonight will not drop off much from what temperatures are
currently across the area this afternoon. Temperatures may
actually start to warm later tonight across southern Missouri as
warmer air spreads north ahead of the approaching trough.

As the upper level trough spreads across the Plains on Saturday a
cold front will spread east into and through the area. Another
round of moderate to heavy rain will develop and track across the
area, again with the heaviest rains occurring across southern
Missouri from late Saturday morning into the early evening hours.
More instability will be in place ahead of the front, so will see
more in the way of scattered storms along the front. The
strongest instability will remain across south of the area, but
around 500 J/kg of MLCAPE will likely be able to develop across
far southern Missouri, generally east of Hwy 65 and south of I-44.
As a result there will be a risk for some severe storms mainly
across southern Missouri where the better instability will be in
place. The storm mode will like be more of the way of line
segments leading to the main risking being damaging winds. Low
level shear will increase ahead of the system. Any line segments
that can surge to the east of east northeast will have a meso
vort potential across far southern Missouri Saturday
afternoon/early evening.

This system should be fairly progressive and the rain should move
east of the area by the overnight hours Saturday. Total rainfall
amounts from this afternoon through Saturday evening will range
from 1 to 3" with locally heavier amounts. The heaviest rain will
occur along and south of the I-44 corridor. A Flood Watch remains
in effect through Saturday evening for southern Missouri.

.LONG TERM...(Sunday through Friday)
Issued at 320 PM CST Fri Feb 23 2018

A brief dry period is then expected Sunday into early next week as
an upper level ridge builds towards the area. Highs early next
week will warm into the 60s. Another system will then track
across the region during the middle of next week bringing
additional rain chances to the region. Behind that system an upper
level ridge and dry weather is expected late next week.

&&

.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 511 PM CST Fri Feb 23 2018

A IFR night is in store with IFR ceilings and vis likely at the
TAF sites as light to moderate rain moves through the area. Winds
will primarily be light tonight and tomorrow. Patchy fog will be
possible as well tonight given the build down of stratus. There
will be some potential for low level wind shear at SGF and BBG.
Rain will likely persist off and on during the day on Saturday
with very low potential for rising into MVFR conditions. A few
thunderstorms are possible Saturday, mainly at BBG and have VCTS
currently for them.


&&

.SGF WATCHES/WARNINGS/ADVISORIES...
MO...Flood Watch through Saturday evening for MOZ057-058-069>071-
     079>083-088>098-101>106.

KS...Flood Watch through Saturday evening for KSZ101.

&&

$$

MESOSCALE...Schaumann
SHORT TERM...Wise
LONG TERM...Wise
AVIATION...Burchfield


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