Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 162346
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
646 PM CDT Wed Apr 16 2014

.SHORT TERM:  (Through Late Tonight)
Issued at 233 PM CDT Wed Apr 16 2014

A rather tranquil night is on tap for the area. The surface low
currently in extreme northwest Iowa will move northeastward tonight
and into Wisconsin by daybreak, with the attendant cold front
stretching from northeast MO into west central MO at 12Z. As a
result the surface pressure gradient will weaken this evening. This
along with an end to deep mixing around sunset will result in
quickly diminishing southerly surface winds. Surface winds do remain
southerly all night but due to extensive lower tropospheric ridging
well into the GOM, low level moisture return will be nil and limited
to an increase in mid-hi level moisture. The associated cloudiness
and southerly winds will keep temperatures warmer than last night.

Glass

.LONG TERM:  (Thursday through Next Wednesday)
Issued at 322 PM CDT Wed Apr 16 2014

A weak cold front will move southeastward through our forecast area
Thursday and Thursday night.  The models depict upper level
divergence over our area Thursday and Thursday evening ahead of an
approaching upper level trough.  Moisture and instability will be
limited with this front, but there should still be scattered showers
along and just behind this front Thursday afternoon and night.  The
threat for showers should end Friday morning with a clearing sky as
the upper level trough moves east of the region.  Only slight
cooling is expected behind the front, mainly across northeast MO and
west central IL Thursday afternoon and night.  Temperatures will
warm back up Friday and Friday night as the upper level heights rise
as the upper level trough moves east of our area and as upper level
ridging centered over the southern Plains moves into our area.  Much
warmer, above normal high temperatures are expected on Saturday as
southerly surface/low level flow returns.  The chance of showers
will return to our area Sunday and continue through Monday as a
shortwave approaches and a weak cold front moves southeastward
through our area Sunday night and Monday.  It appears that there
will be more favorable level low moisture and instability present
with this weak front than the front which will move through our area
Thursday and Thursday night and hence a greater threat for showers
and possibly also thunderstorms.  Ony short lived, slight cooling
expected behind this front, then pronounced warming for Wednesday
with an upper level ridge over the region and strengthening sly/swly
surface/low level flow.  The models are forecasting 850 mb
temperatures rising to around 12-16 degrees C by 00z Thursday.

GKS

&&

.AVIATION:  (For the 00z TAFs through 00z Thursday Evening)
Issued at 642 PM CDT Wed Apr 16 2014

VFR conditions expected. Strong and gusty south wind will relax
and back to the south/southeast this evening. Cold front expected
to move across the region Thursday morning with a wind shift to
the west. Wind to become light and variable Thursday evening.
Confidence in any measurable precipitation is too low at this time
to include in the forecast.

Specifics for KSTL:
VFR conditions expected. Cold front expected to move across the
area late Thursday morning with winds shifting to the west in the
afternoon and then becoming light and variable Thursday evening as
the front settles to the south of the terminal.

CVKING

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...RED FLAG WARNING until 7 PM CDT this evening FOR Audrain MO-
     Boone MO-Callaway MO-Cole MO-Franklin MO-Gasconade MO-
     Jefferson MO-Knox MO-Lewis MO-Lincoln MO-Marion MO-Moniteau
     MO-Monroe MO-Montgomery MO-Osage MO-Pike MO-Ralls MO-Shelby
     MO-St. Charles MO-St. Louis City MO-St. Louis MO-Warren MO.

IL...NONE.
&&

$$

WFO LSX






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