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AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
346 AM CDT THU SEP 3 2015

.SHORT TERM:  (Through Late This Afternoon)
Issued at 313 AM CDT Thu Sep 3 2015

Weak warm advection over central Missouri is producing isolated 
showers northwest of Columbia.  Expect this activity to continue 
this morning for a few more hours...but should be ending between 12Z 
and 15Z as the weak low level jet backs and warm advection shuts 
off.  Remainder of the day looks to be a carbon copy of the past 
couple with high pressure controlling our weather.  Expect highs in 
the 90-95 degree range.  Wouldn't be surprised to see an isolated 
thunderstorm or two this afternoon, but overall chances are 10 
percent or less across the area so have kept the forecast dry for 
today.

Carney

.LONG TERM:  (Tonight through Wednesday)
Issued at 346 AM CDT Thu Sep 3 2015

Stagnant weather pattern will persist at least through Sunday as the 
upper level ridge remains locked in over the center of the country.  
The trof currently over the Pacific Northwest will move east across 
the Rockies into the northern Plains by late Sunday causing 
cyclogenesis over the Dakotas.  Resulting cold front plows southeast 
into Iowa by Monday.  As a result, the temperature and precip 
forecast becomes a little tricky Monday through Wednesday.  While 
Monday may be a repeat of Sunday with respect to temperatures, 
medium range ensemble guidance trends pretty sharply cooler into the 
low to mid 80s on Tuesday, even though we're still in the warm 
sector with the front hanging back across Iowa.  Upper 70s is being 
advertised by guidance across northeast Missouri with low to mid 80s 
further south on Wednesday as the front finally dives southeast into 
our CWFA.  While I do think mid to high chance for thunderstorms as 
indicated by guidance is appropriate for Monday through 
Wednesday...not sure about the temperature forecast.  There isn't 
any airmass change until the front pushes through, and the low level 
thermal ridge is still over our region with 850mb temps in excess of 
+20C.  Low to mid 80s just feels too cool to me until the front 
moves through...regardless of the precip chances.  If I was 
forecasting in a vacuum, I'd keep temperatures at least 5 degrees 
warmer than guidance; however, have kept the forecast temperatures 
close to the ensemble guidance to maintain consistency with 
neighboring offices.

Carney

&&

.AVIATION:  (For the 06z TAFs through 06z Thursday Night)
Issued at 1139 PM CDT Wed Sep 2 2015

A few high-based spotty showers have developed across north
central MO this evening and are persisting as they drift
southeast. Present indications are they will avoid KUIN and will
hopefully dissipate before moving as far southeast as KCOU. Still
anticipating the potential for a short period of fog/br between
09-13z at all terminals except KSTL, with the possibility of
reducing the visibility to 4-6sm. Otherwise VFR flight conditions
to persist through Thursday with few-scattered diurnal cu from
midday into the afternoon.

Specifics for KSTL: 

VFR flight conditions should prevail through the forecast period.

Glass

&&

.PRELIMINARY POINT TEMPS/POPS:
Saint Louis     94  74  94  75 /  10   5   5   5 
Quincy          92  70  93  70 /  10   5   5   5 
Columbia        92  70  93  70 /  20   5   5   5 
Jefferson City  93  70  93  70 /  10   5   5   5 
Salem           91  72  92  72 /  10   5   5   5 
Farmington      92  69  92  69 /  10   5   5   5 

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&

$$

WFO LSX

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