Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 172029

329 PM CDT Sun Aug 17 2014

.SHORT TERM:  (Through Late Tonight)
Issued at 323 PM CDT Sun Aug 17 2014

Surface low/MCV continues to make very slow progress to the east
southeast away from forecast area. Will still see some lingering
light showers/sprinkles for far eastern and southeastern portions
of forecast area this evening. Then begin to dry out with clouds
scattering out a bit. Lows will be in the mid 60s to low 70s.
Another issue tonight could be fog development. Will add mention
of patchy fog after potential issue tonight could be
boundary layer will remain very moist. Due to uncertainty in cloud
cover overnight tonight...elected not add fog to forecast for now.


.LONG TERM:  (Monday through Next Sunday)
Issued at 323 PM CDT Sun Aug 17 2014

Monday will remain dry but will see plenty of cu developing so
temperatures will warm up but not as much as previously thought.
Lowered highs a degree or two. Highs will be in the mid upper 80s.

Next shortwave/cold front to move through region beginning Monday
night. So kept chance pops going through Tuesday. Then system to
stall out over southern portions of forecast area before returning
north as a warm front beginning Tuesday night. Will see rain chances
across most of area Tuesday night, then lift northward out of area
by Thursday, though kept low chance pops going for northern portions
of forecast area through Friday night. During this period, will see
a warming trend, but did lower highs a tad on Tuesday due to warm
front position as well as clouds and precipitation, in the mid 80s
to low 90s. Then temps warm up into the 90s everywhere for the last
half of the work week and into the first part of the weekend. With
frontal boundary lingering just north of forecast area for the
weekend, could see some activity in the northern portions of
forecast area, but hard to pin down at this time.


.AVIATION:  (For the 18z TAFs through 18z Monday Afternoon)
Issued at 1119 AM CDT Sun Aug 17 2014

Good new is the upper level system that has plagued the area is
forecast to pick up speed and is forecast to be over eastern Ohio
by 18z Monday. The bad news is ample low level moisture remains to
keep MVFR/IFR ceilings and visibilities in place overnight into
Monday. Area of light rain moving over east central MO and
southwest IL may be the end of the precipitation as it has a back
edge. HRRR model wants to produce scattered showers this afternoon
but the other short range models trend to dry so will go with the
concensus. Any improvement in cloud conditions this evening will
lead to quick fog development, so in essence: pick your poison.
Expect most terminals to be MVFR to VFR at the end of the forecast

Specifics for KSTL: Not much improvement expected overall until
18z Monday. Extensive area of MVRR/IFR ceilings and fog expected
to remain in place overnight with the surface to boundary layer
relative humidity staying very high. Some light rain moving
through now looks like it will end in an hour or so via radar
trends. If system moves as it is forecast the goal will be to see
VFR by 18z Monday.



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