Area Forecast Discussion
Issued by NWS St. Louis, MO

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000
FXUS63 KLSX 301155
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
655 AM CDT Sat May 30 2015

.SHORT TERM: (Through Monday)
Issued at 309 AM CDT Sat May 30 2015

Cold front stretching from Wisconsin to Kansas will continue to
press southeast today as one last potent shortwave rotates northeast
across the region. PWATS will approach 2 inches ahead of the cold
front, which means showers and thunderstorms will continue to be
very efficient rain producers. Adjusted and extended the Flash Flood
Watch to align with areas that are expected to see the greatest
amounts of rain and convection through this evening, generally the
southeastern half of the CWA.

Still believe measurable preciptiation will shut down quickly this
evening from west to east with only some lingering drizzle and
patchy fog possible overnight. Temperatures will certainly be cooler
behind this front with lows in the 50s and highs only in the 60s on
Sunday and lower 70s on Monday.

CVKING

.LONG TERM: (Monday Night through Friday)
Issued at 309 AM CDT Sat May 30 2015

Temperatures will continue to warm up to near normal levels for
the first part of the work week as the surface ridge moves east
and an upper level ridge tries to build across the Plains into the
Mississippi Valley. While the flow aloft remains northwesterly,
low level flow becomes southerly by Thursday which should allow
some moisture to return to the area. Additionally, the 850mb
thermal ridge builds up across the area Thursday into Friday which
looks to allow temperatures to warm above normal for the end of
the week. Medium range models show a couple of shortwaves trying
to move around the periphery of the upper level ridge from the
middle of the week through Friday, spitting out some light QPF as
they move across the area. Can`t rule out scattered thunderstorms
as this occurs due to the increasing moisture from southerly flow
in the low levels, so slight chance to low chance PoPs provided by
ensemble guidance looks pretty reasonable.

Carney

&&

.AVIATION:  (For the 12z TAFs through 12z Sunday Morning)
Issued at 640 AM CDT Sat May 30 2015

Periods of rain with ceilings at or below 1500 ft and occasional
visibilities at or below 3SM will affect the area today. The upper
level disturbance driving this precipitation will move northeast
through the area today into the evening. Rain should come to an
end from west to east from this afternoon through the evening.
However, expect MVFR ceilings to linger through the end of the TAF
period behind a cold front which will move south in the wake of
the rain. Could see ceilings drop to IFR tonight as the cold air
deepens over the area, though have low confidence this will occur.

Specifics for KSTL:

Periods of rain with ceilings at or below 1500 ft and occasional
visibilities at or below 3SM will affect Lambert today. Exact
timing and heights/visibilities are pretty low confidence as there
are lots of holes in the clouds/precip at this time...and guidance
has been of little help so far this morning. Rain should come to
an end during the early afternoon with some lingering showers in
the vicinity of the terminal likely into early evening. However,
expect MVFR ceilings to linger at least through 12Z Sunday. Could
see ceilings drop to IFR tonight as cold air deepens over the
area, though have low confidence this will occur.

Carney

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...FLASH FLOOD WATCH through this evening FOR Crawford MO-Franklin
     MO-Gasconade MO-Iron MO-Jefferson MO-Lincoln MO-Madison MO-
     Montgomery MO-Reynolds MO-St. Charles MO-St. Francois MO-
     St. Louis City MO-St. Louis MO-Ste. Genevieve MO-Warren MO-
     Washington MO.

IL...FLASH FLOOD WATCH through this evening FOR Bond IL-Calhoun IL-
     Clinton IL-Fayette IL-Greene IL-Jersey IL-Macoupin IL-
     Madison IL-Marion IL-Monroe IL-Montgomery IL-Randolph IL-
     St. Clair IL-Washington IL.

&&

$$

WFO LSX





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