Alert archive / Colorado / Mesoscale Discussions in 2021
Mesoscale Discussion 471
The Storm Prediction Center issued this mesoscale discussion at May 2, 2021, 10:14 AM MDT for 13 counties in Colorado. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- May 2, 2021, 10:14 AM MDT (16:14 UTC)
- Expired
- May 2, 2021, 12:15 PM MDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch unlikely
- Chance of a watch
- 20%
Counties Adams County, CO, Arapahoe County, CO, Boulder County, CO, Broomfield County, CO, Clear Creek County, CO, Denver County, CO, Douglas County, CO, Elbert County, CO, Gilpin County, CO, Jefferson County, CO, Larimer County, CO, Morgan County, CO, Weld County, CO
The radar
The Denver radar (KFTG), 37 km from the middle of the area, began a volume at 16:14 UTC, the scan nearest the moment this went out.
Open the radar archive at this moment
The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.
The watches that followed
Watches SPC issued over any of the same counties within four hours of this discussion.
The nearest sounding before it
Denver, CO (KDNR), launched 12:00Z, 4.2 hours before the alert went out and 128 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1976 m above ground
- 0-6 km bulk shear
- 28 kt
- 0-1 km storm-relative helicity
- -89 m²/s²
- 0-3 km storm-relative helicity
- 10 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
958
ACUS11 KWNS 021614
SWOMCD
SPC MCD 021614
COZ000-NEZ000-WYZ000-021815-
Mesoscale Discussion 0471
NWS Storm Prediction Center Norman OK
1114 AM CDT Sun May 02 2021
Areas affected...North-central to northeast CO
Concerning...Severe potential...Watch unlikely
Valid 021614Z - 021815Z
Probability of Watch Issuance...20 percent
SUMMARY...Initial thunderstorm development may pose a risk for
marginally severe hail and wind through early afternoon. This
initial activity is expected to remain too marginal to capture with
a severe thunderstorm watch. Greater severe potential is expected
later this afternoon and farther east towards the KS/NE border.
DISCUSSION...Convective development is underway across Larimer and
Boulder counties in conjunction with a mid-level impulse shifting
east across the area. Weak low-level east-northeasterlies are
apparent in FTG VWP data and this should contribute to near 30-kt
effective shear amid modest mid to upper-level southwesterlies. As
surface temperatures have already warmed through the 60s into the
low 70s across the adjacent high plains, meager buoyancy has
developed and should increase further as robust insolation
continues. The expectation is for this convection to spread east
across a focused corridor of north-central to northeast CO posing a
threat for marginally severe hail and wind. Development farther
south along the Front Range will likely be necessary to enhance
potential for cluster evolution later today.
..Grams/Dial.. 05/02/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...PUB...BOU...CYS...
LAT...LON 40600558 41060500 41080416 41090362 40550321 39830337
39190402 39110484 39050527 39320589 39740584 40600558SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 2, 11:45 AM MDT | Severe Thunderstorm Watch | SPC | Adams, Arapahoe, Bent, Cheyenne, Crowley, Douglas and 10 more | 7 hr |
| May 2, 1:15 PM MDT | Mesoscale Discussion | SPC | Cheyenne, Elbert, El Paso, Kit Carson, Lincoln, Morgan and 3 more | 90 min |
| May 2, 2:45 PM MDT | Mesoscale Discussion | SPC | Cheyenne, Crowley, Kiowa, Kit Carson, Lincoln, Phillips and 2 more | 90 min |
| May 2, 4:12 PM MDT | Mesoscale Discussion | SPC | Baca, Bent, Prowers | 93 min |
Nearby
Mesoscale Discussions in Colorado, 2021Every mesoscale discussion in 2021
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.