Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 242334
AFDLSX

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
634 PM CDT TUE MAY 24 2016

.SHORT TERM...  (Through Late Tonight)
Issued at 312 PM CDT Tue May 24 2016

Ongoing storms across srn MO are expected to continue to propagate
ESE this afternoon and shud be E of the CWA by 00z. Some lingering
SHRA with isod TS may continue for a couple of hours. Still expect
development just N of the CWA with a few storms drifting south into
the nrn couple of tiers of counties before dissipating. Have kept
PoPs at low chance or less due to uncertainty in timing and
placement.

Focus will be on MCS development across NEB/KS. While it appears the
bulk of the activity will remain N of the CWA. However, as this
system breaks down the upper level ridge, it seems that activity
will drop into wrn portions of the CWA late tonight and likely
persist into Wed morning.  More on that below.

Otherwise, some guidance suggests that additional storms may develop
within the broad WAA further S across the srn half of the CWA. Have
kept PoPs rather generic due to uncertainty in how the event tonight
will unfold.

Tilly

.LONG TERM...  (Wednesday through Next Tuesday)
Issued at 312 PM CDT Tue May 24 2016

Several rounds of convection can be expected for the remainder of
the work week and into the weekend with southwest flow shortwaves
moving through the region coupled with persistent warm, moist and
unstable southerly low level flow.  Convection is expected to sweep
northeastward through our forecast area Wednesday morning into the
early afternoon hours ahead of a shortwave and on the nose of a
south-southwesterly low level jet.  Much of the convection should
shift east-northeast of the forecast area by late afternoon,
although could not rule out a few storms redeveloping during the
late afternoon/early evening along any left over outflow boundaries
from the morning storms.  May be a lull in convective activity
during the late evening and overnight hours Wednesday night. Prefer
the drier solution of the NAM model during this time period over the
GFS.  Looks like mainly just scattered diurnal showers/storms
Thursday afternoon and early evening.  With a little more solar
insolation expected and less morning convection, highs should be
warmer on Thursday and easily around 10 degrees above normal for
late May.  More widespread convection is expected on Friday and
Friday night as an upper level trough approaches our area from the
Plains.  Highs on Friday will be cooler due to the increased cloud
cover and greater coverage of showers/storms.  Fairly widespread
convection will continue on Saturday as the upper level trough
becomes more negatively tilted and moves northeastward through our
area.  Should see less active weather by late Saturday night and
continuing for the remainder of the weekend after the upper level
trough shifts northeast of the region.  For the start of the next
work week the warm and humid weather pattern will continue with
mainly scattered afternoon and early evening showers and storms with
mainly weak southwesterly upper level flow and weak surface winds
due to a weak surface pressure pattern.

GKS
&&

.AVIATION...  (For the 00z TAFs through 00z Wednesday Evening)
Issued at 628 PM CDT Tue May 24 2016

Rain has moved out of forecast area, so kept tafs dry for the most
part. Could see activity move into KUIN as this area gets clipped
by storms/showers, so added vicinity shower mention from 00z to
04z Wed. Otherwise, next chance for rain would be closer to
daybreak on Wednesday as MCS complex forecasted to develop over
Neb/KS could make its way into forecast area. So kept MVFR
thunderstorms for KCOU after 12z Wed and vicinity showers/storms
for rest of taf sites after 14z Wed. Then dry out again by Wed
afternoon, though some scattered redevelopment not out of the
question. VFR conditions and south winds to persist outside of
activity.

Specifics for KSTL:
Rain has moved out of forecast area, so kept metro dry for the
most part. Next chance for rain would be closer to daybreak on
Wednesday as MCS complex forecasted to develop over Neb/KS could
make its way into metro area. So kept vicinity showers/storms
mention after 15z Wednesday. Then dry out again by 19z Wed,
though some scattered redevelopment not out of the question. VFR
conditions and south winds to persist outside of activity.

Byrd
&&

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

$$
WFO LSX



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