Sunrise 5:56 AM   Sunset 7:48 PM Moonrise 2:29 AM   Moonset 12:21 PM

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FXUS63 KLSX 010339 AFDLSX

Area Forecast Discussion...Updated Aviation National Weather Service Saint Louis MO 1039 PM CDT Tue Apr 30 2024

KEY MESSAGES

- Thunderstorms may remain strong or marginally severe as they enter northeast Missouri and west central Illinois late this evening. Wind gusts to 60 mph and perhaps hail up to the size of quarters will be the threat.

- A renewed threat of numerous showers and thunderstorms arrives Thursday afternoon, with a MARGINAL RISK of severe thunderstorms across the western portion of the CWA



SHORT TERM
(Through Late Wednesday Night)
Issued at 200 PM CDT Tue Apr 30 2024

An active spring weather pattern will continue for the foreseeable future with a parade of shortwaves marching across the center of the CONUS. In the near term (next few days) the highest threat of severe thunderstorms remains to our west, but there are indications in the longer range guidance that by early next week we may be in the thick of it again.

The first shortwave we will focus on is currently moving across the Plains and into the upper Midwest. An accompanying cold front will continue to move southeast and provide the focus for thunderstorms to develop across eastern Nebraska, western Iowa, northeast KS and northwest MO this evening. Some of these thunderstorms will become severe. As they move east/southeast and congeal into a line along the front they will likely weaken as diurnal instability wains. Nevertheless, we can't rule out one or two of them remaining strong/severe as they cross the CWA border into northeast MO after 10 PM. The threats with any storm that remains severe would be marginal hail and wind gusts to 60 mph.

The cold front will stall across the CWA on Wednesday and set the stage for isolated to widely scattered thunderstorm chances during the afternoon and evening. The consensus of model guidance has this occurring across the Ozarks. Forecast values of instability and shear do not support widespread severe thunderstorms, but a few could be strong. High temperatures tomorrow will range from the middle 70s north of the front to the upper 80s to the south of the front. Chances of showers and thunderstorms increase Wednesday night as the front starts to advance back north as a warm front.

CVKING

LONG TERM
(Thursday through Next Tuesday)
Issued at 200 PM CDT Tue Apr 30 2024

The next shortwave and cold front will bring a renewed threat of showers and thunderstorms to the region on Thursday/Thursday night.
While subtle timing difference are noted in the plethora of guidance, the overall consensus is that a band of showers and thunderstorms will develop and move west to east across the CWA during the afternoon. SPC currently has the western portion of the CWA outlooked in a Marginal Risk which matches well with the instability and shear values forecast. Temperatures will range from near 80 degrees in central MO, while the eastern CWA climbs into the middle to upper 80s ahead of the front.

The probability of precipitation decreases on Friday as the cold front moves east of the area followed by weak and temporary high pressure settling across the lower Missouri and middle Mississippi River Valleys. Some of the NBM membership has a slower departure of the front and therefore POPs linger longer than I would suspect. Friday's high temperatures will be slightly cool with middle to upper 70's forecast.

The dry weather will not last long as a series of shortwaves in southwest flow aloft will bring renewed chances of showers and thunderstorms through the weekend and into next week. Temperatures will remain seasonal with highs in the upper 70s/lower 80s and lows in the 50s/60s. Latest extended guidance from St. Louis University CIPS and Colorado State University shows a pattern supportive of severe thunderstorms in the CWA next week.

CVKING

AVIATION
(For the 06z TAFs through 06z Wednesday Night)
Issued at 1034 PM CDT Tue Apr 30 2024

The earlier storms moving eastward across Missouri toward the local terminals have mostly dissipated, and are expected to have nearly completely dissipated by the start of the TAF period. KUIN may see a glancing blow by some remnant showers, but confidence in that occurring remains low at the moment. I also can't rule out rain at KCOU and/or KJEF near the start of the period, but confidence in that occurring is even lower than at KUIN.
Otherwise, dry and VFR flight conditions are expected through a majority of the TAF period. Showers and thunderstorms may threaten the area near the end of the period, but details in timing and location relative to terminals is unclear at this time.

Elmore

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

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