Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 301744
AFDLSX

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
1244 PM CDT FRI SEP 30 2016

.SHORT TERM... (Through Sunday Night)
Issued at 254 AM CDT Fri Sep 30 2016

A closed and nearly stacked low pressure system was centered over
TN/KY early this morning. This feature will slowly meander
northward over the next few days, eventually reaching the IN/MI
border by 00z Sun and then quickly moving towards the
northeastern CONUS. As long as the low pressure system remains
nearby, sfc winds will retain a northerly component and
substantial cloud cover will be present, particularly over the
eastern part of the CWA which will be closer to the low pressure
system. Light rain is also expected at times over the eastern CWA
today/tonight.

The combination of northerly winds and substantial cloud cover
will keep daytime high temperatures in the mid 60s to near 70
degrees for today and tomorrow. A slight warm-up is then
anticipated on Sunday due to the decreased influence of the
departing low pressure system.

Kanofsky

.LONG TERM... (Monday through Thursday)
Issued at 254 AM CDT Fri Sep 30 2016

Models depict a brief pd of upper ridging over MO/IL early next
week before a large low pressure system approaches from the west.
Although there is general agreement that this feature will bring
unsettled wx to our area during the middle of the week (roughly
Tue night through Thu night), there remains some model
disagreement over the location of this feature and its evolution.
The 00z ECMWF was farther north and depicted more of an open wave
while the 00z GFS solution had an initial track which was much
farther south but eventually developed into a closed low over the
Dakotas. A general fcst of SChc-Chc PoPs during the middle of the
week looks reasonable attm given the model disagreement.

Kanofsky
&&

.AVIATION...  (For the 18z TAFs through 18z Saturday Afternoon)
Issued at 1237 PM CDT Fri Sep 30 2016

With closed upper low just to our east, will continue to see sc
deck rotate around it. So VFR/MVFR cigs to persist today, lowering
to IFR tonight, especially for taf sites along Mississippi River.
Cigs to lift back to MVFR by mid morning on Saturday. Otherwise,
some scattered showers during the afternoon hours today for STL
metro area and vicinity showers at KUIN. KCOU could see some
sprinkles but not enough coverage worth mentioning in their taf.
As for winds, to persist from the north then back to the northwest
by late tonight. Wind speeds to diminish by sunset.

SPECIFICS FOR KSTL:
With closed upper low just to our east, will continue to see sc
deck rotate around it. So VFR/MVFR cigs to persist today, lowering
to IFR by 07z Saturday. Cigs to lift back to MVFR by 15z Saturday.
Otherwise, some scattered showers during the afternoon hours today
for STL metro area, so kept tempo mention from 18z to 22z Friday.
As for winds, to persist from the north between 10 and 15 kts then
back to the northwest by 07z Saturday. Wind speeds to diminish by
03z Saturday.

Byrd
&&

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

$$
WFO LSX



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