314 
FXUS63 KLSX 021857
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
157 PM CDT Mon Jun 2 2014

.SHORT TERM:  (Through Tonight)
Issued at 130 PM CDT Mon Jun 2 2014

As upper level s/w continues to move sewd, believe ongoing TSRA
will continue to push ewd out of the region thru the afternoon
hours. However, mdls suggest area of cu across ern KS and w
central MO may continue to develop into the evening, eventually
producing TSRA. If these storms do develop, areas most likely to
be impacted are wrn and nrn portions of the CWA. Due to
uncertainty in development and track if these storms do develop,
have kept POPs in the slight chance range for now. Will continue
to monitor development and adjust POPs if/when necessary. 

Mdls also suggest FG may develop tonight, especially across the
nrn third of the CWA. Will also continue to monitor as conditions
continue to develop. 

Tilly

.LONG TERM:  (Tonight through Sunday)
Issued at 404 AM CDT Mon Jun 2 2014

(Tonight-Wednesday)

Thunderstorm chances will continue to be the primary forecast 
concern heading into midweek, and there are lots of different yet 
plausible scenarios regarding the convective trends over the CWA.  
While the NAM keeps the entire area dry tonight, GFS and GEM suggest 
nocturnal convection developing over parts of the FA.  With fairly 
weak but persistent WAA of unstable airmass across the region ahead 
of frontal boundary, some small chance of showers and
thunderstorms seems appropriate.

Still feel that the NAM is a bit too far north with the surface 
boundary on Tuesday, with all of the other synoptic scale models 
suggesting the front will reach the I-70 corridor. The location
of this feature is important, as a low chance of storms should
continue continue to co-exist with its location.  Any storms that
develop Monday night should continue near the boundary on Tuesday
morning, with additional, hit and miss development near the
boundary in the afternoon as the airmass in the warm sector
becomes very unstable with all of the models forecasting MUCAPES
aoa 4000 j/kg.

PoPs and severe weather potential will be increasing dramatically
in northern sections of the CWA on Tuesday night as the very
unstable air begins to interact with a substantial increase of
shear over the region. Shortwave embedded in strengthening mid
level flow will cause surface low to form along stalled front over
the plains near the KS/NE border, with the low then moving east
overnight and causing remnants of front in our area to begin
moving north as a warm front. 00z runs are still in excellent
agreement that intense convection that forms over the mid-Missouri
valley Tuesday evening will grow upscale into an MCS that should
propagate ESE and clip northern sections of the CWA Tuesday night,
but don't think we can totally rule out some severe potential
before the arrival of the MCS...as storms may try to develop along
the Mississippi River as low level jet intensifies and veers
during the predawn hours producing isentropic ascent along and
north of warm front. Moderate risk outlooked by SPC in SWODY2
looks good, and was shifted south a bit to account for some
uncertainly to the exact track of the MCS. Given expected
evolution of this system would think that damaging winds and some
hail will be the primary threats in our CWA, but some tornado
potential will also exist near the warm front due to strong low
level shear/helicity.

Tuesday night's MCS should push out of the region fairly early 
Wednesday morning, with additional thunderstorm development expected 
during the day as cold front in the wake of the surface low sweeps 
south and interacts with the unstable airmass in the warm sector.

(Thursday-Sunday)

Medium range models indicate that baroclinic zone will linger over 
the region during the last part of the week before lifting north 
during the weekend in response to falling heights over the Plains.   
Ripples in the westerlies will interact with the baroclinicity to 
continue the seemingly non-stop forecast of showers and thunderstorms
over most of the CWA.  In this unsettled pattern don't see any 
prolonged period where rain will not be a threat.

Truett

&&

.AVIATION:  (For the 18z TAFs through 18z Tuesday Afternoon)
Issued at 1244 PM CDT Mon Jun 2 2014

TSRA will remain possible for the next few hours at
KSTL/KSUS/KCPS, but shud gradually push SE during the afternoon
hours. With clouds decreasing by sunset, radiational cooling may
allow for FG development at all terminals overnight. Terminals may
also see a brief period of MVFR cigs Tues around sunrise as CU
develops. However, confidence is too low attm. TSRA is expected to
develop Tues along the sfc boundary. However, these TSRA are
currently expected to develop beyond the valid TAF period. 

&&

.PRELIMINARY POINT TEMPS/POPS:
Saint Louis     84  71  89  73 /  30  20  30  40 
Quincy          84  66  87  68 /  10  20  20  80 
Columbia        84  67  88  72 /  20  20  40  40 
Jefferson City  85  68  89  73 /  20  20  40  30 
Salem           83  70  88  71 /  50  10  30  40 
Farmington      82  68  88  71 /  30  20  30  20 

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&

$$

WFO LSX