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Area forecast discussion...updated aviation 
National Weather Service St Louis MO
1211 am CDT Mon may 4 2015

Short term: (through late tonight)
issued at 353 PM CDT sun may 3 2015

The region is under the influence of sthrly flow on the back side of
a sfc ridge centered off the East Coast. An area of shras/sprinkles
has dvlpd in the past hour across N cntrl/NE MO. Even though there
has been an isld lightning strike, I think most of this activity
will remain on the light side through the evng before mvng east of
the nthrn County Warning Area and dssptng. The threat is currently being covered
with sprinkles but mentionable pops may need to be added if the
coverage/intensity increases. A cold front will approach the area
late tonight introducing the threat of shras/tstms into the forecast area after
midnight. The GFS is further south with quantitative precipitation forecast than the rest of the
model suite...though these set ups have the tendency to produce echo
further east and south than any of the models indicate...so have
slight chance pops extending down to i70 to account for this
uncertainty. It should be an unseasonably warm night with most
locations remaining near the 60 due to persistent sthrly flow and
dps in the 50s.

2%

Long term: (monday through next sunday)
issued at 353 PM CDT sun may 3 2015

An upper level ridge will build over our region beginning on Monday
and remain in effective control for much of the work week before
breaking down into a more general SW flow aloft for next weekend.
This will result in a persistence of the above average temps and
above average moisture thru the column--where disturbances, fronts,
or more general areas of forcing will have not too much trouble
resulting in rain or thunderstorms, with the greatest and most
widespread pops set for next weekend associated with SW flow
shortwave disturbances. Most days will have some mentionable chance
for rain.

A surface cold front will be the primary focus for Monday and Monday
night as it is initially stalled Monday morning...remains
quasi-stationary thru much of Monday before retreating north as a
warm front Monday night. High-end chance to likely pops still look
good for areas near the front in far northern MO and west-central
IL, but pops look to taper rapidly heading south with an absence of
discernable forcing. The one opportunity that looks reasonable for
areas further south is Monday morning where warm air advection/sunrise-surprise
rain showers and thunderstorms and rain could make a brief appearance.

A more traditional warm-sector setup will be in place for late
Monday night thru late Wednesday, and should give US a period of dry
wx for most locations.

The ridge begins to breakdown late week with a series of shortwaves
that initially give US a glancing blow but will setup future
disturbances upstream to take a more southerly course for a direct
hit. The above normal temps look set to continue with SW flow aloft
preventing much in the way of frontal intruisions, but better
chances for rain look set across a more widespread area as these
disturbances track more thru the center of our region versus the
fringe.

Max temps each day look to be in the 80s with min temps in the 60s.

Tes

&&

Aviation: (for the 06z tafs through 06z Monday night)
issued at 1154 PM CDT sun may 3 2015

VFR flight conditions are expected to continue to prevail across
the area through Monday evening. Scattered thunderstorms are
likely to drift south out of Iowa between 09z-12z, potentially
impacting the KUIN terminal. However, am not confident enough in
areal coverage to mention more than vicinity thunder in the taf at
this time. Further south, short-range guidance is hinting that
there will be some high-based showers developing over east central
Missouri and southwest Illinois around 12z. Showers should
dissipate by mid morning. VFR conditions with gusty southwest flow
is expected for Monday late morning through the afternoon.
Another round of thunderstorms is expected near a cold front which
will dip into northern Missouri. Coverage over northeast Missouri
and west central Illinois is again questionable, and much of the
activity may stay north of the area. Thunderstorm activity should
diminish through the evening.

Specifics for kstl:

VFR flight conditions and south-southwest flow will prevail at
Lambert. Isolated to widely scattered high based showers look
likely to develop around 12z Monday morning. Think impacts to the
Airport will be minimal...though if a heavier shower happens to
pass over the Airport it could briefly drop visibility to MVFR
range. Showers should dissipate by 14-15z. Wind will be in the
200-220 range through much of the period, increasing to around
12kts during the afternoon with gusts to 20kts. There is a slight
chance of thunderstorms during the late afternoon, but it's much
more likely that any thunderstorm activity will stay well north of
the terminal.

Carney

&&

Lsx watches/warnings/advisories:
MO...none.
Illinois...none.
&&

$$

Weather forecast office lsx

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