354 
FXUS63 KLSX 010452
AFDLSX

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
1152 PM CDT Wed May 31 2017

.SHORT TERM...  (Through Late Thursday Afternoon)
Issued at 346 PM CDT Wed May 31 2017

Ongoing TSRA over wrn MO will continue to move sewd and are expected 
to turn more ely as they approach the CWA based on forward 
propagating vectors. However, believe the line will move just a 
little south of this suggested trajectory based on where better CAPE 
resides. 

Overnight, the sfc ridge axis will shift slightly with the focus for 
TSRA shifting west again. Still expect an MCS to develop over nern 
KS/sern NEB and propagate sewd. How much of this will impact the CWA 
is somewhat uncertain, but expect far wrn portions of the CWA to see 
TSRA late tonight into Thurs morning. The threat shud refocus 
further north during the day, but with sfc boundaries lingering in 
the region, isod to widely sct storms can not be ruled out thru the 
afternoon. 

Have continued trending temps aoa the warmer guidance thru Thurs. 

Tilly

.LONG TERM...  (Thursday Night through Next Wednesday)
Issued at 346 PM CDT Wed May 31 2017

As surface ridge moves off to the east Thursday night, warm front 
to continue lifting slowly northeastward through forecast area. 
Best chances of showers and storms will be along and east of 
Mississippi River, depending on location of warm front, amount of 
instability and strength of low level jet. Isolated strong to 
severe storms will be possible with the main threat being large 
hail. Otherwise, mild conditions to persist with lows in the low 
to mid 60s. Highs on Friday will be in the mid to upper 80s.

Warm front to lift well north of forecast area by Friday evening 
with a brief break in activity. Then as surface low over over 
upper Midwest slides east into Great Lakes region, it will drag a 
cold front across region Saturday through Sunday. Models have 
differences on timing of this system, but still feel that best 
chances will be Saturday afternoon and evening with the storms 
tapering off by Sunday afternoon.

Beyond that could see a secondary front swing through on Monday with 
a round of showers. Otherwise, dry and near normal conditions 
through rest of extended period.

Byrd

&&

.AVIATION...  (For the 06z TAFs through 06z Thursday Night)
Issued at 1152 PM CDT Wed May 31 2017

VFR conditions, outside of TSRA, will prevail at the TAF sites
thru the valid period. Light NE surface winds will veer E-SE
overnight and continue veering towards S-SE during the day on 
Thursday. Main rain chances should be to the southwest of most TAF
sites to preclude mention, but did maintain a VC mention at KCOU 
for very late tonight and Thursday morning with rain over the
mid-MO valley moving in that direction, but this activity is
expected to weaken after sunrise Thursday with rain chances
continuing and sliding eastward, but are rather low after this. 

TES

&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&

$$

WFO LSX