Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 201947
AFDLSX

Area Forecast Discussion
National Weather Service Saint Louis MO
Issued by National Weather Service Kansas City/Pleasant Hill MO
247 PM CDT Thu Apr 20 2017

.SHORT TERM...  (Through Late Tonight)
Issued at 245 PM CDT Thu Apr 20 2017

Front currently making its way through the forecast area is
bringing some showers and thunderstorms to the southern counties.
The trend is for this activity to continue to move toward the ESE,
exiting the forecast area by this evening. Much of the area will
then see a bit of a dry period before more widespread precip
chances reemerge by tomorrow morning.

WFO LSX

.LONG TERM...  (Friday through Next Thursday)
Issued at 245 PM CDT Thu Apr 20 2017

General model consensus is for showers and thunderstorms to pick
back up tomorrow, with off and on chances culminating later in the
day Saturday as a low pressure system traverses through. Moderate
to locally heavy rainfall will be possible later tomorrow through
Saturday. The 12Z GFS and ECMWF agree on a southern MO track
while the Canadian takes the surface low on a much further south
track. Despite these spatial differences, overall model consensus
is for those periodic precip chances through Saturday night, upon
the low`s departure.

The forecast area will enter into a dry period for the latter half
of the weekend into the early part of next week. While there are
increasingly divergent model solutions for the next system
approaching/crossing the region by mid-week, long-term models
depict a front moving through with precip chances popping up along
and ahead of it. The ECMWF is the fastest of the three
aforementioned models with the Canadian the slowest; Tues. night
fropa, early Thur. morning fropa, respectively. Have elected to
lean more toward the slower solution(s) given the typical
tendencies.

WFO LSX

&&

.AVIATION...  (For the 18z TAFs through 18z Friday Afternoon)
Issued at 1249 PM CDT Thu Apr 20 2017

Hinted at some pockets of low end VFR or borderline MVFR CIGs with
the post frontal stratus, but actual MVFR prevailing clouds looks
unlikely. Terminals find themselves on the northern edge of the
precipitation late in the forecast period, so handled with VCSH for
now, but prevailing periods for rain will likely be needed later.

SPECIFICS FOR KSTL: FROPA taking place at the terminals which should
keep heavy rain away, but spotty showers are still possible
behind the front. Generally looking at VFR conditions with perhaps
a few patches of MVFR CIGs for the next few hours. Rain at the
terminals late in the forecast period is a bit uncertain, with the
heavier amounts remaining south of the St. Louis terminals. Could
see periods of showers late in the forecast period, but no
potential flight restrictions are foreseeable at this point.
Updates to the rain activity and potential flight restrictions
will be addressed on upcoming issuance.

WFO LSX

&&

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

$$

WFO LSX



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