Area Forecast Discussion
Issued by NWS St. Louis, MO

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

FXUS63 KLSX 312352

652 PM CDT Thu Jul 31 2014

.SHORT TERM:  (Through Late Tonight)
Issued at 319 PM CDT Thu Jul 31 2014

Another cool and quiet night is expected, as lows overnight drop to
the low to middle 60s across the area, still below normal for this
time of year. Water vapor imagery indicates a shortwave currently
over southwestern Minnesota and northwestern Iowa, and a NW-SE
oriented band of precipitation over western Iowa. The shortwave will
continue to drop southeastward this evening and tonight, and
could be enough to trigger some showers and perhaps an isolated
thunderstorm over far northeast Missouri and west central Illinois.
Feel the window for precipitation in this area is fairly small, as
the shortwave will remain transient and should be east of the
Mississippi River and out of our CWFA by around 06-07Z.  Otherwise,
diurnal cumulus is expected to dissipate across much of the area not
long after sunset, with winds remaining light and variable through
the night.


.LONG TERM:  (Friday through Next Thursday)
Issued at 319 PM CDT Thu Jul 31 2014

Slight changes may be in the offing regarding sensible weather
Friday/Saturday as longwave trough continues to dominate weather not
only over our region...but also the eastern two-thirds of the country.
Although shra/ts has been largely non-existent the past several days...
do believe there is a better chance of seeing isolated activity on
Friday/Saturday...due to better upper-level support and better instability.
Otherwise...persistence is the way to go wrt temps...seasonably cool for
early August.

Temperatures will moderate back toward normal to start off the new work
week with seasonably warm conditions expected for the middle of next week.
Pattern may become more favorable for rain as mid/upper levels become
quasi-zonal and moisture increases ahead of a slow-moving cold front.
However...PoPs only climb into the chance category due to substantial
differences in timing/track of closed low which develops from the northern



.AVIATION:  (For the 00z TAFs through 00z Friday Evening)
Issued at 650 PM CDT Thu Jul 31 2014

Showers over Iowa may affect KUIN later this evening, though they
have shown an overall weakening trend so have not included them
in the TAF site at this time. Some areas of fog are expected to
develop again tonight... particularly near the rivers like they
have in recent nights between 09-13Z. A weak upper level
disturbance will move across the area tomorrow afternoon which
should be enough to generate isolated thunderstorms. The greatest
coverage will be across west central Illinois, so went added VCTS
at KUIN starting at 17Z. The St. Louis metro TAF sites may also
see this chance, though there is enough uncertainty in timing to
keep those TAF sites dry for now.

Specifics for KSTL: Have gone with a dry and VFR TAF with light
winds. There is a slight chance of thunderstorms on Friday
afternoon, though there is enough uncertainty in timing to leave
them out of the forecast for now.



Saint Louis     66  85  65  86 /  10  20  10  20
Quincy          63  81  61  82 /  20  20  10  20
Columbia        63  85  62  84 /  10  20   5  10
Jefferson City  62  85  62  84 /  10  20   5  10
Salem           63  84  61  85 /  10  20  10  20
Farmington      60  81  60  82 /  10  20   5  10




WFO LSX is the U.S. government's official web portal to all federal, state and local government web resources and services.