Alert archive / Colorado / Mesoscale Discussions in 2021
Mesoscale Discussion 801
The Storm Prediction Center issued this mesoscale discussion at May 29, 2021, 12:58 PM MDT for 6 counties in Colorado. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- May 29, 2021, 12:58 PM MDT (18:58 UTC)
- Expired
- May 29, 2021, 3:00 PM MDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch likely
- Chance of a watch
- 80%
Counties Baca County, CO, Bent County, CO, Crowley County, CO, Elbert County, CO, Lincoln County, CO, Otero County, CO
The radar
The Pueblo radar (KPUX), 75 km from the middle of the area, began a volume at 19:00 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, 7.0 hours before the alert went out and 155 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
- 2325 m above ground
- 0-6 km bulk shear
- 20 kt
- 0-1 km storm-relative helicity
- -78 m²/s²
- 0-3 km storm-relative helicity
- 92 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
237
ACUS11 KWNS 291858
SWOMCD
SPC MCD 291858
COZ000-292100-
Mesoscale Discussion 0801
NWS Storm Prediction Center Norman OK
0158 PM CDT Sat May 29 2021
Areas affected...Eastern CO
Concerning...Severe potential...Watch likely
Valid 291858Z - 292100Z
Probability of Watch Issuance...80 percent
SUMMARY...Scattered thunderstorms are expected to develop this
afternoon with a risk for potentially very large hail and damaging
winds. A tornado or two is also possible. Trends are being monitored
and a watch is likely prior to 21z.
DISCUSSION...Isolated thunderstorms are beginning to develop across
the higher terrain of central CO at 1845z, and additional isolated
storms are expected to develop the remainder of this afternoon. A
weak surface low was located south of La Junta CO at 18z with a
moist southeasterly low-level upslope flow across the discussion
area. Surface dew points in the low 50s combined with steep
mid-level lapse rates (in excess of 8 deg C/km) will result in
MLCAPE of 1000-1500 J/kg this afternoon. Modest westerly mid-level
flow will increase with time and contribute to west/northwesterly
deep shear averaging 40 kts.
A supercell storm mode is favored, with a risk for large/very large
hail and strong wind gusts. Locally backed/enhanced low-level flow,
especially near the Palmer Divide and Raton Mesa, may support
stronger low-level rotation and some risk for a tornado.
Convective/observational trends are being monitored and a watch is
likely prior to 21z.
..Bunting/Hart.. 05/29/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...GLD...PUB...BOU...
LAT...LON 38900434 39690402 39840345 39650306 39330309 38970305
38080295 37660239 37290242 37090246 37110334 37670419
38900434SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 29, 1:48 PM MDT | Tornado Watch | SPC | Baca, Bent, Cheyenne, Crowley, Elbert, El Paso and 6 more | 7 hr |
| May 29, 4:54 PM MDT | Mesoscale Discussion | SPC | Crowley, El Paso, Lincoln | 66 min |
| May 29, 5:30 PM MDT | Mesoscale Discussion | SPC | Baca | 90 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.