Mesoscale Discussion 0434
NWS Storm Prediction Center Norman OK
1215 PM CDT Tue Apr 27 2021
Areas affected...portions of northeastern Colorado
Concerning...Severe potential...Watch likely=20
Valid 271715Z - 271945Z
Probability of Watch Issuance...80 percent
SUMMARY...Convective initiation is underway across portions of
northeast Colorado. The threat for severe hail is expected to
gradually increase through the afternoon and a Severe Thunderstorm
Watch issuance is likely.
DISCUSSION...Overcast skies are overspreading a post-cold frontal
airmass across northeast Colorado, with surface temperatures varying
in the lower 50s to near 60F, and with 40-50F dewpoints noted.
Nonetheless, RAP forecast soundings suggest 100 mb deep rich
low-level moisture is in place, and is being overspread by 8+ C/km
mid-level lapse rates (evident via the 12Z DNR observed sounding).
With continued diurnal heating and the approach of an embedded
mid-level vort-max in New Mexico, an uptick in convective coverage
and intensity is expected. Increasing mid-level wind speeds are
fostering 50+ kts of effective bulk shear, suggesting that any
storms that can mature may remain organized long enough to support
the production of large hail. With modest low-level lapse rates in
place, a couple damaging gusts also cannot be completely ruled out.
As such, a Severe Thunderstorm Watch issuance is anticipated.
= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at email@example.com and ask to be removed from WX-STORM. ------------=_1619543791-1996-2874--