Area Forecast Discussion


927 
FXUS63 KLSX 102348 CCA
AFDLSX
Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
544 PM CST Sun Dec 10 2017
.SHORT TERM...  (Through Late Monday Afternoon)
Issued at 323 PM CST Sun Dec 10 2017
Skies were mostly sunny across the area this afternoon.  A warm 
front has moved east of the area allowing temperatures to warm into 
the the upper 40s and lower 50s.  Winds are expected to back 
southwesterly tonight ahead of a cold front that will move across 
the area during the day on Monday.  There will be some increase in 
mid-high clouds late tonight ahead of the next shortwave trough that 
is moving southeast in the northwesterly flow aloft. Skies will 
turn partly sunny by tomorrow, but expect a mainly dry passage of 
the attendant cold front as there will be limited moisture for the
shortwave to work with. Lows tonight will be close to mid 
December normals. Highs tomorrow will climb above normal ahead of 
the cold front as there will be deep mixing ahead of the front and
850mb temperatures are around +5C. 
Britt
.LONG TERM...  (Monday Night through Next Sunday)
Issued at 323 PM CST Sun Dec 10 2017
The upper flow pattern this week will continue to be dominated by 
northwesterly flow aloft with weak shortwaves moving across the 
area. The first shortwave will be the one that will move through 
on Monday. Both the ECMWF and GFS show a second one with an 
attendant cold front crossing through MO/IL late Wednesday with 
another one late Thursday. By next weekend, the GFS/ECMWF are 
showing the eastern CONUS longwave moving off to the east and a 
trough setting up in the Plains. This may be enough for just a 
slight chance of precipitation over parts of the area on Saturday 
night. 
With northwesterly flow aloft this week, expect temperatures to be 
at or below normal.  850mb temperatures this week will fall to -10C 
or lower at times.  May see temperatures to climb back above normal 
by next weekend when upper flow turns back out of the southwest.
Britt
&&
.AVIATION...  (For the 00z TAFs through 00z Monday Evening)
Issued at 536 PM CST Sun Dec 10 2017
VFR flight conditions will prevail tonight through early Monday 
afternoon with periodic waves of mid-high clouds in the northwest 
flow aloft. Surface winds will gradually back overnight and then 
increase and becoming gusty from the west-southwest on Monday 
morning as a surface trof moves east. In the wake of the surface 
trof, a potent cold front will move southeastward during the 
afternoon accompanied by lowering cigs and gusty northwest winds.
SPECIFICS FOR KSTL: 
VFR flight conditions will prevail tonight through Monday afternoon 
with periodic waves of mid-high clouds in the northwest flow aloft. 
Surface winds will gradually back overnight and then increase and 
becoming gusty from the west-southwest on Monday morning as a 
surface trof moves east. In the wake of the surface trof, a potent 
cold front will move through the terminal in the early afternoon 
accompanied by lowering cigs and gusty northwest winds. MVFR flight 
conditions/cigs will move into KSTL on Monday evening.
Glass
&&
.FIRE WEATHER...  
Issued at 323 PM CST Sun Dec 10 2017
There will be an heightened fire danger over parts of central, 
east central, and southeast Missouri on Monday afternoon. 
Temperatures are expected to climb to around 60 while the minimum 
relative humidity falls below 30 percent and sustained winds will 
be between 12-15 mph with higher gusts.
Britt
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&
$$
WFO LSX