225
ACUS11 KWNS 291815
SWOMCD
SPC MCD 291815
MTZ000-WYZ000-292045-

Mesoscale Discussion 1064
NWS Storm Prediction Center Norman OK
0115 PM CDT Wed May 29 2024

Areas affected...portions of extreme northern Wyoming into southern
and central Montana

Concerning...Severe potential...Watch possible

Valid 291815Z - 292045Z

Probability of Watch Issuance...40 percent

SUMMARY...The threat for severe wind gusts will increase as storm
coverage becomes greater this afternoon. The severe gust threat
should initially be sparse in southwestern MT early this afternoon,
but should become more abundant as storms approach eastern MT.
Convective trends are being monitored for the more robust
severe-gust threat and associated need for a WW issuance.

DISCUSSION...Low-level lapse rates continue to steepen (i.e. the 7-8
C/km range) as diurnal heating continues to support boundary layer
mixing. A pronounced mid-level trough is overspreading the northern
Rockies and tracking eastward, resulting in deep-layer ascent and
accompanying potential for increased thunderstorm coverage through
the afternoon. As thunderstorms strengthen and overspread the
deepening boundary layer, the steep low-level lapse rates will
foster severe gust potential. Severe gusts should initially remain
isolated over southwestern MT. However, as the storms gradually move
eastward amid deeper moisture and higher instability (i.e. 1000+
J/kg MLCAPE), severe gusts could potentially become more common.
Timing in a relatively greater uptick in potential severe wind gust
production is not entirely certain. However, convective trends are
being monitored to pinpoint when a greater-than-isolated severe gust
threat may materialize, at which point a WW issuance may become
necessary.

..Squitieri/Guyer.. 05/29/2024

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...BYZ...GGW...RIW...TFX...

LAT...LON   45120619 44950650 44650785 44550966 44581072 44801119
            45031145 46800973 47700832 48050708 47780635 47040581
            45810566 45520564 45120619