Alert archive / Colorado / Mesoscale Discussions in 2016

Mesoscale Discussion 995

June 20, 201615 counties in Colorado

The Storm Prediction Center issued this mesoscale discussion at Jun 20, 2016, 2:38 PM MDT for 15 counties in Colorado. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Jun 20, 2016, 2:38 PM MDT (20:38 UTC)
Expired
Jun 20, 2016, 4:45 PM MDT
In force
2 hr
Issued by
the Storm Prediction Center
Chance of a watch
20%

Counties Adams County, CO, Alamosa County, CO, Arapahoe County, CO, Boulder County, CO, Broomfield County, CO, Clear Creek County, CO, Custer County, CO, Denver County, CO, Douglas County, CO, Fremont County, CO, Gilpin County, CO, Huerfano County, CO, Jefferson County, CO, Park County, CO, Teller County, CO

The radar

The Denver radar (KFTG), 99 km from the middle of the area, began a volume at 20:38 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

Denver, CO (KDEN), launched 12:00Z, 8.6 hours before the alert went out and 188 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.

Skew-T log-pSkew-T log-p diagram, Denver, CO at 12:00Z on 2016-06-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Denver, CO at 12:00Z on 2016-06-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -36 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
2874 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
-36 m²/s²
0-3 km storm-relative helicity
100 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.0

Open this sounding in Storm Lab

The text

As transmitted.

578 
ACUS11 KWNS 202038
SWOMCD
SPC MCD 202038 
COZ000-202245-

MESOSCALE DISCUSSION 0995
NWS STORM PREDICTION CENTER NORMAN OK
0338 PM CDT MON JUN 20 2016

AREAS AFFECTED...COLORADO FRONT RANGE/PALMER DIVIDE AND ADJACENT
HIGH PLAINS

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 202038Z - 202245Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...THUNDERSTORMS ARE EXPECTED TO INCREASE ACROSS THE FRONT
RANGE AND PALMER DIVIDE AND POSSIBLY EXPAND INTO THE ADJACENT HIGH
PLAINS LATER THIS AFTERNOON. ISOLATED HAIL AND DAMAGING WIND ARE
POSSIBLE...THOUGH COVERAGE IS EXPECTED TO REMAIN TOO ISOLATED FOR
WATCH ISSUANCE.

DISCUSSION...TSTMS ARE INCREASING ACROSS THE FOOTHILLS INTO THE
FRONT RANGE IN AN UPSLOPE FLOW REGIME. WHILE MIDLEVEL FLOW IS
WEAK...LOW-LEVEL ELYS VEERING TO MIDLEVEL WLYS ARE SUPPORTING AROUND
20-30 KTS OF EFFECTIVE SHEAR...WHICH WILL SUPPORT SOME ORGANIZED
STORM STRUCTURES GIVEN THAT WEAK-TO-MODERATE INSTABILITY /MUCAPE OF
750-1500 J/KG/ IS IN PLACE. WARM MIDLEVEL TEMPS WILL TEND TO LIMIT
THE SEVERE HAIL RISK...THOUGH ISOLATED INSTANCES OF HAIL APPROACHING
1 INCH IN DIAMETER ARE POSSIBLE WITH THE STRONGEST UPDRAFTS. SOME
THREAT OF DAMAGING WIND WILL ALSO EXIST...ESPECIALLY IN
LOWER-ELEVATION AREAS WHERE THE BOUNDARY LAYER IS DEEPER AND WARMER.

IT IS UNCLEAR HOW FAR EAST CONVECTION WILL DEVELOP/PROPAGATE...BUT
THERE IS SOME POTENTIAL FOR A FEW CELLS OR A SMALL COMPLEX TO MOVE
OFF OF THE FOOTHILLS INTO AREAS ALONG AND NORTH OF THE PALMER DIVIDE
LATER THIS AFTERNOON. AT THIS TIME...THE COVERAGE AND MAGNITUDE OF
THE THREAT APPEARS TOO LIMITED FOR WATCH ISSUANCE.

..DEAN/GUYER.. 06/20/2016

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...PUB...BOU...

LAT...LON   37420597 38720599 39460600 40100555 40260517 40310460
            40270408 39490385 39180455 38350490 37310494 37420597

Nearby

Mesoscale Discussions in Colorado, 2016Every mesoscale discussion in 2016

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.