Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 061817

117 PM CDT TUE OCT 6 2015

Issued at 1252 PM CDT Tue Oct 6 2015

Overall fcst is in good shape. The sprinkles from this mrng have
pretty much dssptd. Other than updating the sky grids based on the
chaotic satellite image...the other elements seem on track.



.SHORT TERM:  (Through Late This Afternoon)
Issued at 350 AM CDT Tue Oct 6 2015

Scattered sprinkles/light rain showers have developed over
northwestern MO early this morning ahead of a weak vort max in
northeastern KS. The area with light sprinkles also coincided with
an area of moisture convergence between H8-H7 as well as a pocket of
steeper lapse rates. A few sprinkles or light rain showers could
move into central or northeastern MO this morning.

The slow warming trend continues today with afternoon highs expected
to be a few degrees warmer than yesterday. This should lead to highs
in the 70s across most of the area, although a few sites in
southeastern MO and/or southwestern IL could reach the lower 80s
depending on how quickly the clouds clear out.


.LONG TERM:  (Tonight through Monday)
Issued at 350 AM CDT Tue Oct 6 2015

Forecast trends will remain essentially unchanged in this
forecast package: dry and mild weather is expected tonight and
into Wednesday, followed by a chance of showers and thunderstorms
in the Thursday-Friday time frame as upper level shortwave and
trof and associated cold front work their way across the
Mississippi Valley. The only real change in the forecast was a
slight slowing of the southward progression of PoPs across the
area, as all of the 00z guidance was just a bit slower with the
shortwave and cold front than earlier solutions. The slower
solutions also dovetails with the idea of holding onto low chance
PoPs over southern sections of the CWA on Friday. Have decided to
maintain highest PoPs for this event at around 50% for
now...although MET and MAV are considerably lower operational
ECMWF-based MOS guidance is indicating likely PoPs in many areas
with the fropa. Additional adjustments to PoPs will probably be
necessary with time as the details become a bit more clear.

Daytime highs will be above average on Wednesday and Thursday with
highs in the middle 70s to lower 80s.  However, temperatures will be
dipping below seasonal norms by Friday, as the post-frontal cool-
down shaves some 10-15 degrees off of max temps.

Medium range solutions are still indicating that this cool down will
be brief, as the progressive UA regime across the CONUS allows a
strong ridge to build back into the nations`s midsection for the
start of next week.  Guidance is suggesting 850MB temps of at least
16-18C on Monday, which would certainly support highs back in the
80s over most of the CWA. Lack of moisture and any significant
dynamics/lift suggest dry weather will accompany this warmup.



.AVIATION:  (For the 18z TAFs through 18z Wednesday Afternoon)
Issued at 1252 PM CDT Tue Oct 6 2015

A swath of MVFR CIGs stretching from SW MO NE into SE IA are in
the process of rising early this aftn. Think that all areas will
become VFR by later this aftn...but it will be a slow process due
to plenty of mid/high clouds streaming overhead. Guidance
indicates that areas where the stratus persists thru the aftn may
see CIGs build back down to MVFR levels after midnight. Models are
also suggesting more MVFR fog towards early morning as well. Not
confident in either of these so have left out of the fcst for
now. Otherwise expect plenty of VFR clouds thru the prd with light
Nrly flow below 10 kts.

Specifics for KSTL:

Plenty of VFR clouds thru the fcst prd with the potential for a
few hrs of high end MVFR VSBYs towards sunrise Wed mrng. Not
confident enough to include in the fcst attm.





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