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fxus63 klsx 162357 

Area forecast discussion...updated aviation
National Weather Service Saint Louis MO
657 PM CDT Mon Sep 16 2019

Short term... (through late tonight)
issued at 255 PM CDT Mon Sep 16 2019

Weak convergence was noted along a back-door cold front which had
settled into the region. Scattered rain showers/thunderstorms and rain have already
developed farther eastward along the boundary in in/KY/OH where
metars showed stronger surface convergence. Based on satellite
depictions of the cumulus field over MO/Illinois as well as BUFKIT
soundings showing very little cinh, the previous shift's
expectation for isolated rain showers/thunderstorms and rain still looks on track. However,
the location of these pops has been adjusted slightly eastward to
reflect the latest position of the surface front.

Lows tonight should range from the mid 60s in SW Illinois (on the cooler
side of the stalled boundary) to around 70 in central MO. The
combination of light winds and moisture pooling near the front
could also lead to light fog development tonight. The only
inhibiting factor will be some mid/high clouds spilling into the
region, and this may result in patchy fog development within any
breaks in the clouds.


Long term... (tuesday through next monday)
issued at 255 PM CDT Mon Sep 16 2019

Warm and humid conditions are expected to persist for the rest of
the week due to the combined influence of an upper ridge axis as
well as southerly flow along the periphery of a surface high
pressure center. Highs will generally be in the upper 80s to lower
90s and overnight lows will be in the 60s to lower 70s.

Some models show a few weak disturbances during the week which
could produce isolated rain showers/tsra, but the best chance for
widespread rainfall appears to be from Friday through Sunday night
when a low pressure system lifts through the north-central Continental U.S.
Towards Canada. Models all show a secondary disturbance moving
into the trough after the first low pressure system has lifted
northeastward, but there is poor agreement between models on the
resulting large scale upper air pattern. That said, models do
appear to be in general agreement that a pattern change will bring
a period of wetter weather to the region this weekend and perhaps
into early next week. Temperatures should be lower this weekend
due to clouds and rain, and there is at least a chance that a
frontal boundary could even push through the region and bring
cooler temperatures to the area.



Aviation... (for the 00z tafs through 00z Tuesday evening)
issued at 647 PM CDT Mon Sep 16 2019

VFR conditions are expected through the period with relatively
minimal issues throughout the area.

A remnant boundary, left behind by a washed out cold front,
currenetly stretches northwest to southeast, roughly along the
Mississippi River this evening. Remnant cu resides along this
boundary and will continue to fade after sunset, in addition to
mid to high clouds that are streaming off a system will to our
northwest. All bases are VFR.

Light and variable winds overnight may lead to some patchy fog
over southeast Missouri and southwest Illinois. Chances are fairly
low than any will have direct impact on terminals. Winds turn
easterly at 5-10 knots through Tuesday.

Specifics for kstl:

VFR conditions are anticipated through the period with mid to high
clouds streaming overhead. Light and variable winds become
easterly at around 5 knots Tuesday.



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