Area Forecast Discussion
Issued by NWS St. Louis, MO

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894
FXUS63 KLSX 261157
AFDLSX

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
657 AM CDT Sat May 26 2018

.SHORT TERM...  (Through Late Tonight)
Issued at 336 AM CDT Sat May 26 2018

Still some lingering isolated showers and storms over far eastern
and southeastern portions of forecast area as weak upper level trof
slides through. In the meantime, another complex has developed over
southeastern Iowa and is tracking to the southeast. Still hard to
say if it will hold together long enough for it to clip far northern
portions of forecast area. For now kept slight chance pops for
northern 4 counties til 11z. After 12z, kept the slight chance pops
for far southeastern portions of forecast area through midday. Then
expand slight chance pops for entire forecast area for the afternoon
hours due to possible weak remnant MCV sliding through region as
well as CAPES in excess of 2000 J/kg, which could help to trigger
shower/storm activity.

Will see activity linger into the evening hours and gradually
diminish.

As for highs today, it will remain rather hot with highs in the
upper 80s to low 90s. Another mild night tonight with lows in the
mid 60s to low 70s.

Byrd

.LONG TERM...  (Sunday through Friday)
Issued at 336 AM CDT Sat May 26 2018

The synoptic pattern at the start of the long term period will
feature a general blocking pattern over much of the CONUS, with an
upper-level ridge over the central CONUS and a trough across the
Southeast. This regime will keep warm conditions over the region
through the period, with some chances of generally diurnal
convection.

Sunday will feature a ridge attempting to nudge into portions of the
central Plains and the Midwestern states. The influence of this
feature should be enough to allow for generally dry conditions
across much of the region. However, portions of southeast MO and
southwest IL will still be on the eastern periphery, which will make
this area susceptible to some weak PV anomalies sliding southeast
around the ridge. Additionally, guidance is suggestive that a weak
surface boundary will be located across this general area as well.
Therefore, can`t completely dry out the forecast on Sunday and will
continue with a slight chance of a few showers/storms. Given most of
the region is expected to remain dry, think it will end up being the
hottest day of the period given 850mb temps in the 18-20C range.
Highs will likely climb into the low/mid 90s which could threaten
some record values. Monday will be very similar to Sunday, although
some enhanced mid/high clouds could keep temps a couple degrees
cooler. Once again think most areas will remain dry, but can`t rule
out a rogue shower/storm over southeast MO/southwest IL on the
periphery of the upper-level ridge.

Sunday night into Monday it appears what is likely to be Tropical
Storm Alberto will make landfall along the Southeast Gulf Coast.
This system, while the center is likely to remain off to the
southeast, could still spread some enhanced moisture into our
region. Therefore, precipitation coverage is once again expected to
increase Tuesday into the end of next week. Temperatures will be
slightly cooler given the expected cloud cover, with highs expected
in the mid/upper 80s which is still above normal for this time of
year.

Deitsch
&&

.AVIATION...  (For the 12z TAFs through 12z Sunday Morning)
Issued at 655 AM CDT Sat May 26 2018

VFR conditions expected at all taf sites. Isolated showers and
storms possible this afternoon and evening, but hard to pin down
if they will affect taf sites. So kept tafs dry for now.

SPECIFICS FOR KSTL:
VFR conditions expected at all taf sites. Isolated showers and
storms possible this afternoon and evening, but hard to pin down
if they will affect taf sites. So kept tafs dry for now.

Byrd
&&

.CLIMATE...
Issued at 326 PM CDT Fri May 25 2018

Memorial Day Weekend Temperature Records

                 Records Highs    Record High Mins

Saturday 5/26
    St. Louis      98 (1953)         75 (2012)
    Columbia       93 (1953)         71 (1953)
    Quincy         95 (1911)         74 (1914)

Sunday   5/27
    St. Louis      93 (2012)         76 (2012)
    Columbia       92 (2012)         70 (2006)
    Quincy         94 (1911)         73 (1914)

Monday   5/28
    St. Louis      94 (2012)         76 (2012)
    Columbia       91 (2012)         72 (2012)
    Quincy         94 (1914)         72 (2012)


&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&

$$

WFO LSX



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