Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 072054

354 PM CDT WED OCT 7 2015

.SHORT TERM:  (Through Late Tonight)
Issued at 354 PM CDT Wed Oct 7 2015

Persistent cloud cover over much of eastern Missouri and southwest
Illinois will likely continue to hang over the area tonight.  The
stagnant pattern will begin to break down late tonight as the
shortwave over the northern Plains dives southeast and breaks the
ridge that`s been sitting over the mid Mississippi Valley.  Think
this will be the thing that finally clears out this persistent cloud
cover.  MOS guidance temperatures have been working out very well
the past couple of nights, so have continued to follow it closely
for tonight.


.LONG TERM:  (Thursday through Next Wednesday)
Issued at 354 PM CDT Wed Oct 7 2015

The surface reflection of the shortwave will move from Minnesota
southeast into the Great Lakes region by 06Z Friday.  The associated
surface front should enter northern Missouri by 00Z Friday and will
move south through the area and should be south of Farmington by 12Z
or so.  Should be pretty warm ahead of the front on Thursday in west-
southwest flow, so I leaned toward the warmer guidance members.
Still think scattered showers and a few thunderstorms are likely
along and ahead of the front; however I am reluctant to go higher
than 50 PoPs with the FROPA due to lack of deep moisture return.  A
cool Canadian high will drop down into the Mississippi Valley behind
the front on Friday.  Expect temperatures to fall back to near or
just below seasonal normals with this high.

Cool down will be short-lived though as the ridge shifts southeast
and southwest flow returns to the mid Mississippi Valley.
Temperatures will rise back above normal Sunday and then drop again
Tuesday and Wednesday as another front moves through the area.  The
FROPA looks dry at this time due to lack of moisture return.



.AVIATION:  (For the 18z TAFs through 18z Thursday Afternoon)
Issued at 1149 AM CDT Wed Oct 7 2015

Between the persistent stratocumulus cloud mass between COU and
the St Louis metro area and the diurnal cumulus clouds developing
on the periphery of the stratocumulus cloud deck it appears that
a cloud ceiling around 3500-4500 feet should be the general consensus
for the taf sites this afternoon. Much of the low level cloud deck
may scatter out this evening with the loss of daytime heating.
Mid-high level cloudiness should spread into the area tonight
which should help to limit fog potential. The NAM model MOS
guidance is likely too robust on its forecast of stratus and fog
late tonight/early Thursday morning. Light surface winds will
become swly by late Thursday morning as the weak surface ridge
over our area this afternoon shifts southeast of the region and a
cold front approaches.

Specifics for KSTL: Low level, VFR cloud ceiling should scatter
out early this evening with mainly mid-high level clouds tonight
and Thursday. Light surface wind will become swly by late Thursday
morning, increasing to 8-9 kts Thursday afternoon.



Saint Louis     63  84  59  68 /   5  10  50  30
Quincy          60  82  54  66 /   5  30  50  10
Columbia        59  83  55  67 /   5  10  50  20
Jefferson City  59  84  56  68 /   5  10  50  20
Salem           59  81  58  69 /   5   5  50  50
Farmington      57  81  58  66 /   5   5  50  50




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