Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 270925

Area Forecast Discussion
National Weather Service Saint Louis MO
325 AM CST Sun Nov 27 2016

.SHORT TERM...  (Through Late Tonight)
Issued at 324 AM CST Sun Nov 27 2016

Stratus associated with dense fog that was over southwestern MO will
continue to lift northeast through forecast area this morning. As
winds pickup today, will eventually see this stratus lift and
scatter out. In the meantime as deepening low over central plains
begins to lift northeast today, will see increasing mid and high
clouds. Precipitation chances with this system will gradually
increase from west to east with best chances from late this
afternoon through tonight. Not a lot of instability with this
system, so most of precipitation to be in the form of showers. Weak
CAPES up to about 500 J/kg could trigger isolated thunderstorms. So
kept mention of isolated thunder in for this evening.

Otherwise, despite warm southerly winds today, the increasing clouds
will dampen the warm up a bit with highs in the 50s. With main cold
front not moving through til Tuesday, lows tonight will remain
rather mild for this time of year, in the mid 40s to low 50s.


.LONG TERM...  (Monday through Saturday)
Issued at 324 AM CST Sun Nov 27 2016

Main focus continues to be precip chances on Mon thru Mon night.
Within this period, mdls are in fairly good agreement with the
heaviest precip, and best chances, being across the srn and ern
portions of the CWA on Mon with the precip exiting the area Mon
evening. Have maintained low chances for TS on Mon as the trof swings
thru the area, tho threat will remain limited.

With questions on cloud cover and precip during the day on Mon and
given a larger spread in MOS guidance, have made only small changes
to temp forecast for Mon. With more insolation expected on Tues,
have trended twd the warmer guidance.

After fropa late Tues, the region remains under CAA thru the
remainder of the forecast period as the low slowly moves ewd. Mdls
suggest the sfc ridge building into the region late in the period.
This is expected to result in a prolonged dry period with temps near
seasonal average.



.AVIATION...  (For the 06z TAFs through 06z Sunday Night)
Issued at 1127 PM CST Sat Nov 26 2016

IFR conditions likely at all sites tonight as low stratus advects
into the region. Stratus has now made it into COU, and will
continue to move northeast tonight. It has struggled a bit in the
past hour or so likely due to downsloping off the Ozarks, but
should continue to fill in through the early morning hours. Have
continued to favor more stratus than fog given the tightening
surface pressure gradient, although some fog still remains
possible. Have gone prevailing IFR, but some localized LIFR will
be possible as well especially at COU/SUS.

Otherwise, stratus should mix out by the mid to late morning
hours, leading to mainly VFR conditions by Sunday afternoon.
Showers will move in from the west late Sunday afternoon into
Sunday evening, along with the potential for some MVFR cigs.
Southerly winds will also become gusty late Sunday afternoon into
Sunday evening, with gusts in excess of 20-25 knots likely.

IFR stratus deck continues to slowly build northeast. The better
coverage remains off to the west and it has struggled to push
northeast thus far likely due to some downsloping. However,
guidance is in general agreement the stratus will fill in over the
next few hours, thus will continue with an IFR forecast. Expect
most cigs to be in the FL006-FL009 range, but a brief dip into
LIFR isn`t out of the question. Otherwise, stratus will mix out by
late Sunday morning with VFR conditions commencing. Southerly
winds will gust to around 25 knots late Sunday afternoon into
Sunday evening as a few showers approach the terminal.



Saint Louis     55  48  60  45 /  10  80  70  50
Quincy          52  47  58  41 /  50  90  50  30
Columbia        55  49  61  39 /  50  70  50  20
Jefferson City  57  51  61  40 /  40  70  50  20
Salem           53  46  55  45 /   5  80  90  60
Farmington      54  46  56  43 /  10  70  80  50




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