|Mesoscale Discussion 194|
< Previous MD Next MD >
Mesoscale Discussion 0194
NWS Storm Prediction Center Norman OK
0317 PM CDT Wed Mar 18 2020
Areas affected...southwest and south-central Arizona
Concerning...Severe potential...Watch unlikely
Valid 182017Z - 182245Z
Probability of Watch Issuance...5 percent
SUMMARY...Thunderstorms capable of marginally severe hail and wind
are possible across southwest and south-central Arizona this
afternoon and into the evening. Given the marginal severe threat, a
watch issuance is unlikely.
DISCUSSION...An upper low spinning over northern Baja California is
beginning to pivot and will eject northeastward into Arizona this
evening. As large-scale ascent spreads over southern Arizona, a mix
of elevated and surface-based storms is expected with a transition
to surface-based storms likely as surface dewpoints increase to the
upper 40s and low 50s F. With mid-level lapse rates steepening and
cold temperatures aloft, marginally severe hail appears to be the
main threat. Stronger winds aloft could be transported to the
surface within downdrafts possibly resulting in marginally severe
winds, especially in areas with a deeper, well-mixed boundary layer.
A few CG lightning flashes have already been observed in southern
Arizona with initial convection. Storms will likely develop roughly
on a northwest-southeast line from near Yuma down the eastern shore
of the Gulf of California, before pivoting more north-northeastward
across southwest and south-central Arizona as the upper low begins
to pivot this afternoon into the evening.
...Please see www.spc.noaa.gov for graphic product...
LAT...LON 32071366 32381482 32721485 33411451 33751376 33881279
33671163 32871099 32261083 31661087 31421155 32071366
Top/All Mesoscale Discussions/Forecast Products/Home