Area Forecast Discussion
Issued by NWS St. Louis, MO
FXUS63 KLSX 032053
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
353 PM CDT Sun May 3 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 CWA 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 FA after
midnight. The GFS is further south with QPF 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.
.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
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 WAA/sunrise-surprise
SHRA and TSRA 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
Max temps each day look to be in the 80s with min temps in the 60s.
.AVIATION: (For the 18z TAFs through 18z Monday Afternoon)
Issued at 104 PM CDT Sun May 3 2015
VFR fcst thru the prd. The region is on the backside of a large
sfc ridge that is fcst to remain anchored just off the east coast.
This will keep the area in return flow for an extended prd.
Guidance indicates that a cold front will approach the region
tonight but should stall along or near the IA/MO border. This will
limit the best precip chances to those areas and have included a
VCSH group at KUIN late tonight to account for the
threat...though not confident that precip will make it that far
south. Can`t completely rule out precip further south tonight into
Monday mrng near I70 as these types of patterns often produce
isld light precip further east and south than expected.
Specifics for KSTL:
Dry VFR fcst with sthrly flow...diurnal cu and aftn gusts.