492 
FXUS63 KLSX 060338
AFDLSX

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
1038 PM CDT Sat Nov 5 2022

.SHORT TERM...  (Through Late Sunday Night)
Issued at 224 PM CDT Sat Nov 5 2022

Latest surface analysis is showing a deep low over Wisconsin with a 
cold front extending south through eastern Illinois into western 
Kentucky and Tennessee.  There was also a weak trough extending 
southwestward through Iowa into northern Missouri.  The tight 
pressure gradient around the low was continuing to produce wind 
gusts into the 30-40 mph range across the CWA this afternoon.  The 
latest HREF is showing that the low will continue to move northeast 
this afternoon and this evening which should allow the pressure 
gradient to relax some.  In addition, forecast soundings are showing 
decoupling after sunset which should also lead to the winds 
decreasing this evening.

Latest water vapor imagery is not only showing the deep low over the 
western Great Lakes associated with the Wisconsin surface low, but 
also another upper low along the Montana/Saskatchewan border that 
the HREF has moving east into Ontario by late tomorrow. The 
attendant cold front will move southeast across Missouri and 
Illinois during the afternoon. This will be a dry frontal passage 
with the dynamics staying well north of the area and little 
moisture to work with. 

Lows tonight will be close to early November normals behind today's 
cold front.  With mainly sunny skies and southwest winds ahead of 
the front and 850mb temperatures climbing back to around +10C, highs 
will warm back up to just above normal. 

Britt

.LONG TERM...  (Monday through Next Saturday)
Issued at 224 PM CDT Sat Nov 5 2022

There is fairly decent agreement between GFS/ECMWF/CMC and their 
ensemble means that the upper pattern will become highly amplified 
by midweek as trough digs into the western CONUS. This will 
initially cause 500mb heights to rise over Missouri and Illinois as 
the upper high over lower Mississippi Valley builds northward. There 
will be a slight chance of showers on Monday night as a weak impulse 
moves northeast across Missouri in the southwesterly flow aloft.  A 
better chance of rain will come Thursday into Friday when the 
longwave trough moves east with its attendant cold front across the 
area.  Given that amount of ascent with the dynamic trough and 
available Gulf Moisture seen in the GEFS IVT plots, the increased 
PoPS from this run of the NBM looks reasonable.  Precipitation 
probabilities from the NBM and the DESI support this.

Temperatures will be on the rise through the early to middle part of 
next week as 850mb temperatures will be in the 10-14C range before a 
cold front moves through on Thursday.  The NBM and DESI temperature 
spread show little spread through midweek which increases confidence 
that temperatures will slowly warmup through Wednesday. Confidence 
is not as high on Thursday given questions on how quickly the front 
will move through.  Expect much cooler temperatures for the end of 
the week as 850mb temperatures will drop below 0C.

Britt

&&

.AVIATION...  (For the 06z TAFs through 06z Sunday Night)
Issued at 1030 PM CDT Sat Nov 5 2022

Today's gusty southerly winds have fallen off at all terminals 
this evening, with sustained winds sitting between 5 and 10 kts.
Atop these modest surface winds, a 35-40 kt low level jet is 
developing from central MO into west-central IL. This will result
in LLWS conditions at KCOU and KJEF, and we've also introduced
LLWS to the KUIN TAF given weaker surface winds than what we were
previously expecting. LLWS conditions will abate in the morning as
we begin to mix out, with SW winds gradually diminishing through 
the day. A dry cold front will move into the area tomorrow
afternoon/evening, turning weak winds to the NNW.

BSH

&&

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

$$

WFO LSX