Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 101607
AFDLSX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ST LOUIS MO
1107 AM CDT Thu Apr 10 2014

.UPDATE:
Issued at 1055 AM CDT Thu Apr 10 2014

Cold front is beginning to enter the northern CWA at the moment,
and expect it to reach close to a Vandalia to Belleville to Rolla
line by 6 pm before it begins to stall tonight. Temperatures are
warming nicely ahead of the cold front, and are already in the
lower to middle 70s in several places at 11 am, so will need to
increase high temperatures in most areas. Atmosphere is dry, and
do not see much instability available on any of the the models.
However, there is a decent amount of ascent ahead of the shortwave
moving through, so will maintain the slight chances of
showers/thunderstorms for this afternoon and keep the 30 pops for
tonight.

Britt

&&

.SHORT TERM:  (Through Late This Afternoon)
Issued at 357 AM CDT Thu Apr 10 2014

Frontal boundary beginning to make its way into northwestern
Missouri as of 07z. It will continue to track to the southeast
today, before stalling out over southern Missouri tonight. Initially
low level moisture will be lacking as well as any instability. Could
see some isolated showers develop far north late this morning and
spread southeast along and east of Mississippi River. By mid
afternoon, dewpts to rise into the upper 40s ahead of frontal
boundary and will see capes between 100 and 200 J/kg as well as very
steep lapse rates, so raised pops after 21z for areas along and east
of a Fulton to Pittsfield line and added mention of thunderstorms.
As for high temperatures today, despite increasing mid and high
clouds, warm south to southwest winds ahead of front will allow
temps to warm up into the upper 60s to mid 70s.

Byrd

.LONG TERM:  (Tonight through Wednesday)
Issued at 357 AM CDT Thu Apr 10 2014

Showers and some thunderstorms to persist through Friday along
and south of I70 before tapering off as system weakens and exits
region. Despite frontal boundary being south of forecast area, not
a lot of caa with this system so lows will range from the low 40s
north to the low 50s south. Despite easterly flow on Friday, highs
to warm up into the upper 60s to low 70s.

Dry weather to persist Friday night and Saturday with southerly flow
returning to region ahead of next weather system. Lows Friday night
will be rather mild, in the upper 40s to mid 50s with highs on
Saturday in the 70s. Still some concern that we could see scattered
showers and some thunderstorms develop during the day on Saturday as
some extended models continue to hint at a warm front developing
south of forecast area and lift northward. But confidence is low so
kept mention out for now. Then main system to slide through Saturday
night through Monday with best chances of showers and thunderstorms
Sunday and Sunday night. Much colder air to filter in behind system
for the early part of next week with highs only in the upper 40s to
mid 50s on Monday and Tuesday with overnight lows in the 30s.
Temperatures will begin to moderate a bit by mid week next week.

Byrd

&&

.AVIATION:  (For the 12z TAFs through 12z Friday Morning)
Issued at 641 AM CDT Thu Apr 10 2014

A cold front currently located across northwest MO will move
southeast today and this evening, passing through the St. Louis area
between 20-21z. A stout south-southwesterly LLJ now positioned
through central and eastern MO is producing LLWS conditions, but
these will cease by 14-15z as mixing gets well underway and gusty
southwesterly surface winds develop. Flight conditions are expected
to be predominately VFR through the forecast period, however there
is a window from around 21z-03z across east central MO into IL
where we could see some showers and possibly thunder. The coverage,
timing, and exact location is uncertain at this point but the
region from IL into the OH valley appears more favored. At this
point I have VCSH mentioned at KCPS.

Specifics for KSTL:

A stout south-southwesterly LLJ now positioned through the area is
producing LLWS conditions, but these will cease by 14-15z as
mixing gets well underway and gusty southwesterly surface winds
develop. A cold front will pass through the St. Louis area
between 20-21z. Flight conditions are expected to be predominately
VFR through the forecast period, however there is a window from
around 21z-03z where we could see some scattered showers and
possibly thunder in the area. The coverage, timing, and exact
location is uncertain at this point, but the region from IL into
the OH valley appears more favored, so I have left the TAF dry.

Glass

&&

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

$$

WFO LSX






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