Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 131105
AFDLSX

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
605 AM CDT Thu May 13 2021

.SHORT TERM...  (Through Late Friday Afternoon)
Issued at 312 AM CDT Thu May 13 2021

The ridge axis extending from the Great Lakes region southwestward
into Kansas will slowly slide to the southeast over the next 24 to
36 hours. So clear and dry conditions will prevail with slowly
moderating temperatures. Highs today will be in the mid to upper 60s
with lows tonight in the 40s.

By Friday, as the surface ridge slowly shifts east of the region,
winds will back to the south once again. The latest HREF, as well as
NAM and GFS model runs are still indicating a warm front will
develop across northern Kansas into central Missouri with a complex
of showers and storms developing on the nose of a 35 to 40 kt low
level jet over eastern Nebraska late tonight. The complex will slide
southeast into portions of central and northeast MO as well as west
central IL, as it weakens by Friday afternoon.

Byrd

.LONG TERM...  (Friday Night through Wednesday)
Issued at 312 AM CDT Thu May 13 2021

Even though an active weather pattern sets up through next week,
there will be plenty of dry time with temperatures near normal.

By Friday night, another warm front develops, extending from a
surface low over eastern Colorado eastward along the
Missouri/Arkansas border. However, the exact location of the front
is hard to pin down as the ensemble and deterministic models have
differing solutions on its location. Otherwise it will be another
wet period as an MCS develops over eastern Kansas on the nose of a
30kt+ low level jet and slides east along the front on Saturday
before weakening.

By Saturday night, the warm front will become nearly stationary
across our forecast area. It will be a focus for several more rounds
of showers and storms through next week as we remain in a persistent
moist southerly low level flow. The moisture combined with low-mid
level warm air advection ahead of relatively weak shortwaves will
result in convective initiation along and just north of the front
through next Wednesday, especially late Saturday night through
Sunday.

Byrd
&&

.AVIATION...  (For the 12z TAFs through 12z Friday Morning)
Issued at 603 AM CDT Thu May 13 2021

VFR flight conditions through the forecast period with light and
variable winds. Could see some diurnal cu develop over the St.
Louis metro area after 17z today, then dissipate by 00z Friday, so
added mention to KSTL and KCPS TAFs.

Byrd
&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&

$$
WFO LSX


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