Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 222027

Area Forecast Discussion
National Weather Service Saint Louis MO
327 PM CDT MON AUG 22 2016

.SHORT TERM...  (Through Late Tonight)
Issued at 323 PM CDT Mon Aug 22 2016

SFC ridge will move E thru the OH Vly tonight keeping the FA in
southerly return flow. Models depict bands of low level moisture
convergence that move NE across the area tonight but the column will
not had enough time to sufficiently don`t think there
will be much precip prior to 12Z. As such...clouds will be slow to
slow increase from the SW after 6Z. Due to the southerly flow...and
late night clouds...tonight will not be as cool as last night with
most locations in the lower 60s. The exception is locations E/SE/S
of the STL metro where influence of the SFC ridge will be greater
allowing winds to be lighter and clouds will be later to arrive
which will let temps drop a bit more...into the upper 50s. There
could be another round of river valley fog in these same


.LONG TERM...  (Tuesday through Next Monday)
Issued at 323 PM CDT Mon Aug 22 2016


Vort max will quickly eject out of the Red River Valley on Tuesday
morning. This feature combined with broad low-level warm/moist
advection should help maintain what is expected to be isolated-
scattered showers and thunderstorms during the day on Tuesday. Do
not have the greatest confidence in how this activity will evolve
as best moisture convergence during the day on Tuesday outruns the
better DCPVA just downstream of the shortwave trough at mid/upper
levels. Believe some activity will make it into central Missouri
in the late morning timeframe...but uncertain as to exactly how
prevalent the coverage will bet looks like isolated-
scattered. By late afternoon...some of the showers and
thunderstorms may push as far east as the Mississippi River. Highs
on Tuesday will be near that of today...mainly because the low-
level warm advection gets offset by the accompanied increase in
sky cover.

(Tuesday Night - Next Monday)

The remainder of the forecast period continues to look fairly active
with multiple rounds of showers and thunderstorms possible into
early next week. This will be due to a frontal boundary at the
surface which will waver across the mid-Mississippi Valley. Front
will first pass through the CWA on Thursday as a cold front
before moving back to the north and east as a warm front sometime
early next weekend. Certainly will be some dry time across the
area over this period...but presence of frontal boundary beneath
southwesterly flow aloft is suggestive of an overall wet forecast
period. Currently...highest chances of showers and thunderstorms
look to be from Tuesday night through Wednesday night across
northern sections of the forecast area. Highest chances of dry
weather meanwhile would be in what looks to be that short window
between when the cold front progresses through the CWA (Friday)
and the return of the boundary as a warm front into the western
CWA on Saturday.

Temperatures throughout the extended look to be seasonable during
the day and slightly above normal most nights. However...daytime
temperatures will be highly sensitive to degree of cloudiness and
coverage of showers and storms.



.AVIATION...  (For the 18z TAFs through 18z Tuesday Afternoon)
Issued at 1231 PM CDT Mon Aug 22 2016

The region will remain under the influence of high pressure as it
moves from the OH Vly this aftn to the Mid-Atlantic tomorrow. This
puts the entire area in southerly return flow on the backside of
the high. The southerly flow will introduce more moisture into
the region tonight with a small chance for SHRAs/TSTMs by late Tue
mrng across cntrl MO with better chances beyond the end of the
fcst prd.


VFR fcst with southerly flow thru the prd and winds aob 10kts.
There is a small chance for precip in the last few hrs of the TAF
prd late Tue aftn...with better chances Tue evng.





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