529
ACUS01 KWNS 271948
SWODY1
SPC AC 271947

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0247 PM CDT Thu Mar 27 2025

Valid 272000Z - 281200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PORTIONS OF THE
CENTRAL PLAINS TO LOWER MISSOURI/MIDDLE MISSISSIPPI VALLEYS AND
SOUTH TEXAS...

...SUMMARY...
Isolated to scattered large hail and localized severe wind gusts are
possible across parts of the Lower Missouri/Mid-Mississippi Valleys.

...20z Update...
The Slight Risk was removed from portions of northeastern Kansas
into southwestern Iowa and northwestern Missouri. It appears there
remains a conditional risk of a storm or two redeveloping in this
region through the afternoon/late evening, but overall coverage of
severe risk will remain low. Within this region, a pseudo stationary
front/warm front is located, with large scale forcing weak in the
absence of any pronounced upper-level trough. Through the afternoon
and evening, low-level jet response is expected which will help
augment weaker forcing and aid in thunderstorm development but
consensus is mainly for storms across far western Missouri into
central Iowa. Within this region, storms are expected to be largely
elevated, with potential primarily being large hail and a severe
gust or two. Overall, the severe threat is appropriately covered
with a Marginal Risk given the likely low coverage of the severe
threat.

Across southern Texas, the Marginal Risk removed across the upper
Texas Coast region to mainly encompass the area from Corpus Christi
to Brownsville westward. The northern extent of the Marginal Risk
continues along the Rio Grande into Big Bend. Damaging wind risk
will continue across south Texas through the afternoon before
redevelopment is expected across Mexico through the evening. This
secondary round of convection will pose a risk for damaging wind and
large hail.

..Thornton/Smith.. 03/27/2025

.PREV DISCUSSION... /ISSUED 1128 AM CDT Thu Mar 27 2025/

...Central Plains to Lower Missouri/Middle Mississippi Valleys...
Scattered thunderstorms, including a few lingering strong storms,
continue late this morning from eastern KS into northern MO within a
warm-air advection regime.  Morning raob data over the central Great
Plains indicated the northeastern periphery of the EML is located
over the lower MO Valley.  Strong heating in wake of the early day
convection will result in moderate buoyancy developing into
northeastern KS later this afternoon.  Models show a flattening mid-
to upper-level ridge through tonight.  Nebulous/weak forcing at best
is expected in the vicinity of a warm front/outflow intersection
later this afternoon.  However, the erosion of CINH may enable a few
isolated thunderstorms to develop late this afternoon into the
evening.  Recent HRRR runs and the 12 UTC model-run members of the
HREF show a dearth of storm development.  Confidence in appreciable
storm coverage is lowering for diurnally based storm initiation and
casting uncertainty in terms of the potential severe threat.
Nonetheless, supercellular development could occur in the presence
of moderate instability and favorable wind profiles featuring around
35-40 kt effective shear magnitudes.  A greater coverage of elevated
storms may occur tonight as the low-level jet reestablishes and
storms expand eastward regionally. Large hail is the most probable
hazard in both regimes.

...South Texas...
Visible-satellite imagery shows an extensive cloud shield and
convective cloud debris across much of south TX into the upper
coast, and farther west into the Big Bend region.  This is in
response to a slow-moving upper trough which is forecast to move
across northern Mexico toward Deep South Texas by Friday morning.
This episodic convection across northern Mexico into adjacent
portions of TX should limit heating during the day.  Forecast
soundings show seasonably moist profiles from the surface through
the mid levels subduing lapse rate magnitudes.  Mid-level flow will
translate through the base of the trough, south of the international
border into the lower Valley of Texas by early evening.  However,
considerably weaker flow with north extent (i.e., Edwards Plateau)
and uncertainty regarding destabilization farther north cast
uncertainty on storm intensity across south-central TX.  The
low-level jet will remain focused across south Texas aiding in
regenerative storm development and an occasional isolated severe
threat may occur with the stronger storms.

$$