Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 211945
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
245 PM CDT Tue Apr 21 2015

.SHORT TERM: (Through This Evening)
Issued at 237 PM CDT Tue Apr 21 2015

Cumulus field continues to increase across southern Missouri this
afternoon with a few storms developing along a weak convergence
zone that stretch across the Ozarks. Can`t rule out a few reports
of hail or wind with these isolated to widely scattered
thundershowers but beleive threat is very small for widespread
impact. Othwerwise, breezy condtions will continue with west winds
gusting to 30 MPH at times.

CVKING

.LONG TERM:  (Wednesday through Next Tuesday)
Issued at 237 PM CDT Tue Apr 21 2015

The weather pattern is more reminiscent of winter, than
spring, across the center of the CONUS this afternoon with a deep
closed upper level low spinning across the Upper Peninsula of
Michigan and accompanying trof stretching far and wide from the
northern Plains to New England. A shortwave rotating south-southeast
on the resultant northwest flow aloft across the lower Missouri and
middle Mississippi River Valleys will bring another cold front south
across the CWA tonight. While a few showers are possible with the
front, the bigger story will be the continued below normal
temperatures that will be with us through at least Thursday morning.
High temperatures will struggle to get out of the 50s again on
Wednesday and frost is looking more and more likely for Thursday
morning. Will include patchy frost area-wide late Wednesday night
into Thursday morning for now and let later shifts determine need
for any increase in coverage and potential headlines. Would be far
more confident if cloud cover was going to be completely absent
during the period, but middle and high level clouds could start
edging back north overnight and limit coverage of frost.

Aforementioned cloud cover returning to the area will be in response
to rising heights as the next storm system that will affect our
region begins to approach from the west. This system has Pacific
origins and will be somewhat undercutting the predominant upper
level trof that currently encompasses the western 2/3rds of the
CONUS.  Models are beginning to converge on the track of the surface
low (just to our south) and all indicate a very good chance of
measurable rain heading into the first half of the weekend. Have
continued the trend of slowly increasing PoPs for Friday afternoon
through Saturday morning with up to an inch of rainfall possible.

Northwest flow will re-establish itself across the region in the
wake of the low pressure system. High pressure, although temporary
should allow for one completely dry day this coming weekend on
Sunday. It appears that a series of upper level disturbances will
bring renewed chances of showers to the area Sunday night through
Tuesday with temepratures remaining below normal through the entire
extended period.


CVKING

&&

.AVIATION:  (For the 18z TAFs through 18z Wednesday Afternoon)
Issued at 1228 PM CDT Tue Apr 21 2015

Mid level clouds along I-70 corridor this afternoon with some weak
instability over the region, could still see some showers and
isolated thunderstorms develop, but feel they will be south of taf
sites. Otherwise, gusty west winds to prevail before cold front
sinks south across region this evening. Scattered showers expected
just ahead of front, so kept tempo mention of MVFR vsbys/showers in
tafs except KCOU where dry conditions should prevail. Winds will
veer to the northwest behind the boundary.

Specifics for KSTL:
Mid level clouds along I-70 corridor this afternoon with some weak
instability over the region, could still see some showers and
isolated thunderstorms develop, but feel they will be south metro area.
Otherwise, gusty west winds to prevail before cold front sinks
south by 06z Wednesday. Scattered showers expected just ahead of
front, so kept tempo mention of MVFR vsbys/showers between 02z and
06z Wednesday. Winds will veer to the northwest behind the boundary.

Byrd

&&

.PRELIMINARY POINT TEMPS/POPS:
Saint Louis     44  59  42  65 /  30   5   5   5
Quincy          36  54  35  62 /  20   5   0   5
Columbia        41  57  39  63 /  20   5   5   5
Jefferson City  41  57  39  64 /  30   5   5  10
Salem           44  56  38  62 /  30  10   5   5
Farmington      44  59  40  62 /  40  10   5  10

&&

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

$$

WFO LSX



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