Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 271807
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
107 PM CDT Sun Jul 27 2014

.SHORT TERM:  (Through Late This Afternoon)
Issued at 234 AM CDT Sun Jul 27 2014

The cold front has been rather slow moving thus far and stretched
across eastern IA through northwest MO into central KS at 07z.
Areas of fog have developed across portions of northeast Missouri
and west central Illinois where there was a bit more precipitation
yesterday and and the winds were light. The CWA was also void of
any precipitation. The closest showers and thunderstorms were
occurring in an east-west band from just northeast of KUIN to
east of KCMI and were associated with a region of moisture
convergence associated with the westerly low level wind max. The
shoft range guidance suggests that there could be some westward
development into the CWA over the next few hours, but the general
trend should be for this to push east through the early morning
hours as the cold front moves southeast. The cold front motion
will accelerate as the morning progresses in response to the upper
low/trof over the upper MS Valley digging southeastward toward the
Great Lakes. The northwest wind shift with the cold front should
also keep the fog as a short-lived phenomena. The air mass ahead
of the front will remain sufficiently moist and unstable to merit
low chance pops until fropa through the CWA around midday. Increasing
northwest winds in the wake of the front will usher drier and
cooler air into the region, predominately this afternoon.

Glass

.LONG TERM:  (Tonight through Saturday)
Issued at 234 AM CDT Sun Jul 27 2014

Surface high pressure will slowly build into the area tonight and
in ernest on Monday as the high center settles southward into the
northern Plains. The high will dominate the region through the
first part of the week with a deep longwave trof anchored across
eastern NOAM, bringing more below average temperatures. During the
later part of the week, there will be a few disturbances aloft
dropping southeastward across the region and into the base of the
upper trof. These features will have a weak surface reflection but
could generate a few showers and/or thunderstorms while also
helping maintain the below average temps.

Glass

&&

.AVIATION:  (For the 18z TAFs through 18z Monday Afternoon)
Issued at 1245 PM CDT Sun Jul 27 2014

Expect VFR flight conditions and gusty northwest wind to continue
to prevail this afternoon. A large area of stratocumulus clouds is
headed south through Iowa toward the area; however ceilings are
AOA 3500 FT all the way up into Minnesota and Wisconsin. Also,
guidance is indicating that the leading edge of this cloud deck
will likely continue to dissipate this afternoon into the evening.
There may be some redevelopment tonight, tho am not confident it
will become a solid ceiling again. If it does, it should be
between 2000-3000FT. Clouds should dissipate by mid-morning Monday
and VFR conditions should prevail after that.

Specifics for KSTL:

Expect VFR flight conditions and gusty northwest wind to continue
to prevail this afternoon. Some uncertainty as to how far south
the large area of VFR stratocumulus over the Upper Midwest will
get, but current indications are that it will dissipate before
reaching Lambert. There may be some redevelopment tonight, tho am
not confident it will become a solid ceiling again. If it does, it
should be between 2000-3000FT. Clouds should dissipate by mid-
morning Monday and VFR conditions should prevail after that.

Carney

&&

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

$$

WFO LSX





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