Alert archive / Arkansas / Mesoscale Discussions in 2021
Mesoscale Discussion 1948
The Storm Prediction Center issued this mesoscale discussion at Nov 21, 2021, 1:02 PM CST for 36 counties in Arkansas. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Nov 21, 2021, 1:02 PM CST (19:02 UTC)
- Expired
- Nov 21, 2021, 3:30 PM CST
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch unlikely
- Chance of a watch
- 5%
All 36 counties
Arkansas County, AR, Calhoun County, AR, Clark County, AR, Cleburne County, AR, Cleveland County, AR, Conway County, AR, Craighead County, AR, Cross County, AR, Dallas County, AR, Drew County, AR, Faulkner County, AR, Garland County, AR, Grant County, AR, Hempstead County, AR, Hot Spring County, AR, Howard County, AR, Independence County, AR, Jackson County, AR, Jefferson County, AR, Lee County, AR, Lincoln County, AR, Lonoke County, AR, Monroe County, AR, Montgomery County, AR, Nevada County, AR, Ouachita County, AR, Perry County, AR, Pike County, AR, Poinsett County, AR, Prairie County, AR, Pulaski County, AR, Saline County, AR, St. Francis County, AR, White County, AR, Woodruff County, AR, Yell County, AR
The radar
The Little Rock radar (KLZK), 29 km from the middle of the area, began a volume at 19:01 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 nearest sounding before it
Little Rock, AR (KLZK), launched 12:00Z, 7.0 hours before the alert went out and 214 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
- 3 J/kg
- Mixed-layer CIN
- -177 J/kg
- Mixed-layer LCL
- 869 m above ground
- 0-6 km bulk shear
- 48 kt
- 0-1 km storm-relative helicity
- 273 m²/s²
- 0-3 km storm-relative helicity
- 231 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
913
ACUS11 KWNS 211903
SWOMCD
SPC MCD 211902
ARZ000-212130-
Mesoscale Discussion 1948
NWS Storm Prediction Center Norman OK
0102 PM CST Sun Nov 21 2021
Areas affected...Arkansas
Concerning...Severe potential...Watch unlikely
Valid 211902Z - 212130Z
Probability of Watch Issuance...5 percent
SUMMARY...Thunderstorms are expected to increase in number this
afternoon and evening across Arkansas. Hail and gusty thunderstorm
winds may be possible with the strongest thunderstorms. However, any
severe potential should remain too isolated to warrant a watch.
DISCUSSION...An isolated intense thunderstorm is currently moving
across Jackson County in northern Arkansas. This thunderstorm has a
history of producing nickel-sized hail across Independence County.
The expectation is that additional thunderstorms should develop
across Arkansas this afternoon and evening in the vicinity of an
approaching cold front.
The overall thermodynamic environment appears marginal-at-best to
support large hail and severe criteria surface winds. However,
strong tropospheric shear and dynamic storm-scale processes may
support hail, generally around 1 inch, and strong, gusty
thunderstorm winds capable of damage with the strongest
thunderstorms.
Given the highly isolated nature of the expected threat, a watch is
not expected.
..Marsh/Guyer.. 11/21/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...MEG...LZK...SHV...
LAT...LON 34429396 35019349 35959178 36019074 35769017 35169036
34249102 33789133 33459194 33569290 33749379 33989412
34429396Nearby
Mesoscale Discussions in Arkansas, 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.