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FXUS63 KLSX 060452

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
1052 PM CST Thu Dec 5 2019

.SHORT TERM...  (Through Late Friday Night)
Issued at 324 PM CST Thu Dec 5 2019

The approaching surface cold front, driven by the mid level 
shortwave, will drive light rain into the region late tonight into 
early Friday morning. The majority of this rain will stay south 
of I- 70, though brief periods of light rain cannot be ruled out 
along the Columbia-St. Louis-Salem, IL line. Both the front and 
light rain exit the area Friday morning, leaving the remainder of 
Friday dry. Behind the front, northerly winds will advect cold air
into the region. This cold air advection combined with lingering 
low stratus will help keep temperatures much cooler than recent 
days, with highs mostly in the 40s. Temperatures on Friday will 
peak in the around sunrise before slowly falling through the 
morning hours, then remaining steady during the afternoon.


.LONG TERM...  (Saturday through Next Thursday)
Issued at 324 PM CST Thu Dec 5 2019

A rapidly moving surface high builds into the region in the wake of 
Friday's system and keeps the weekend largely precipitation free. As 
it moves out of our area Saturday winds will veer to the south and 
we will return to above normal temperatures in the 50s Sunday 
through Monday.

As the weekend surface high continues eastward out of the Midwest 
another surface low, attached to a deepening mid level trough, edges 
into the region Sunday night. This system will provide our next 
round of precipitation starting Sunday night into Monday night. The 
mid level trough deepens as it moves through the CWA on Monday, and 
steers the surface low out of the area to the northeast. As the 
surface low lifts out of the area Monday parallel to the slow moving 
cold front, guidance suggests a lingering chance of precipitation 
across the area through Monday night. Some of this precipitation may 
end as light snow before moving out of the area completely. A 
surface high building into the area in the wake of this strong 
surface low will keep the forecast precipitation free Tuesday 
through the end of the period.

The passage of this cold front continues to mark a significant shift 
in temperatures as highs Tuesday through the end of the period will 
top out in the mid 20s to mid 30s. While this isn't particularly 
chilly for December, it is about 10 degrees below normal and will 
feel cool after the past several days of above normal



.AVIATION...  (For the 06z TAFs through 06z Friday Night)
Issued at 1035 PM CST Thu Dec 5 2019

Not a lot of changes from the prev TAFs. Still expect MVFR or low
VFR cigs to develop as the cold front pushes south through the
area. Winds will become northerly and increase. Winds will
diminish late Fri afternoon and into the evening. Best chances for
rain are at STL/SUS/CPS overnight, but do not anticipate visbys 
dropping below VFR. 



Saint Louis     42  44  30  49 /  40  20   0   0 
Quincy          33  38  25  46 /   5   5   0   0 
Columbia        36  42  28  50 /  40  10   0   0 
Jefferson City  38  43  28  52 /  60  10   0   0 
Salem           44  48  29  47 /  50  40   0   0 
Farmington      44  49  29  51 /  90  70   0   0 



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