Alert archive / Colorado / Mesoscale Discussions in 2010

Mesoscale Discussion 607

May 18, 201016 counties in Colorado; Banner County, Cheyenne County, Kimball County, Nebraska; Albany County, Laramie County, Wyoming

The Storm Prediction Center issued this mesoscale discussion at May 18, 2010, 11:42 AM MDT for 16 counties in Colorado; Banner County, Cheyenne County, Kimball County, Nebraska; Albany County, Laramie County, Wyoming. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: May 18, 2010, 11:42 AM MDT (17:42 UTC)
Expired: May 18, 2010, 1:45 PM MDT
In force: 2 hr
Issued by: the Storm Prediction Center

All 21 counties

Adams County, CO, Arapahoe County, CO, Bent County, CO, Cheyenne County, CO, Crowley County, CO, Elbert County, CO, Kiowa County, CO, Kit Carson County, CO, Lincoln County, CO, Logan County, CO, Morgan County, CO, Otero County, CO, Prowers County, CO, Washington County, CO, Weld County, CO, Yuma County, CO, Banner County, NE, Cheyenne County, NE, Kimball County, NE, Albany County, WY, Laramie County, WY

The radar

The Denver radar (KFTG), 51 km from the middle of the area, began a volume at 17:45 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.

Tornado Watch 185May 18, 12:45 PM MDT

The nearest sounding before it

Denver, CO (KDNR), launched 12:00Z, 5.7 hours before the alert went out and 63 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 482 J/kg
Mixed-layer CIN: -196 J/kg
Mixed-layer LCL: 1137 m above ground
0-6 km bulk shear: 21 kt
0-1 km storm-relative helicity: 62 m²/s²
0-3 km storm-relative helicity: 51 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

340 
ACUS11 KWNS 181742
SWOMCD
SPC MCD 181742 
COZ000-NEZ000-WYZ000-181945-

MESOSCALE DISCUSSION 0607
NWS STORM PREDICTION CENTER NORMAN OK
1242 PM CDT TUE MAY 18 2010

AREAS AFFECTED...SERN WY...EXTREME SWRN NEB PNHDL...ERN CO

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY 

VALID 181742Z - 181945Z

MID-DAY MESOANALYSIS SHOWS THE LEE CYCLONE BEGINNING TO DEEPEN NE OF
KPUB AND AN EVOLVING DENVER CYCLONE.  MID-LVL DRY SLOT WITHIN NOSE
OF THE UPR LVL JET STREAK WAS SURGING INTO CO.  THERE HAVE BEEN
VARYING AMOUNTS OF MID/HIGH-LVL CIRROFORM CLOUDS TO THE LEE OF THE
MOUNTAINS...BUT MODEST HEATING HAS OCCURRED ACROSS ESPECIALLY ERN
CO.  LLVL SELYS WERE TRANSPORTING UPR 40S/NEAR 50 DEG F SFC DEW
POINTS TO THE E/NE OF THE AFOREMENTIONED CYCLONES AND GIVEN STEEP
LAPSE RATE ENVIRONMENT...MLCAPES WERE ALREADY APPROACHING 1000 J/KG.

HIGH-BASED CBS HAVE BEEN INCREASING ALONG/W OF THE DIVIDE PER VSB
SATL IMAGERY.  ACTIVITY MAY TRY TO ROOT INTO THE UNSTABLE BOUNDARY
LAYER E OF THE FRONT RANGE THROUGH THE AFTN AS CINH CONTINUES TO
ERODE /LIKELY WITH MID-60S TEMPERATURES/.  INITIAL STORM DEVELOPMENT
MAY OCCUR INVOF THE DENVER CYCLONE WITH SUBSEQUENT DVLPMT SWD INTO
SERN CO AFTER 20-21Z.  STORMS WILL MOVE ENE AND WILL GROW INTO
SUPERCELLS WITH VERY LARGE HAIL OWING TO INCREASING EFFECTIVE SHEAR.
 TORNADO THREATS WILL BE MAXIMIZED WITHIN THE DENVER CYCLONE/N SIDE
OF PALMER DIVIDE...BUT ISOLD TORNADOES WILL BE POSSIBLE ANYWHERE IN
THE DISCUSSION AREA.  EVENTUALLY... STORMS WILL CONGEAL INTO SVRL
LINEAR SEGMENTS AS THEY MOVE/DEVELOP INTO THE LWR PLAINS TOWARD
NEB/KS BORDER WITH HIGH WINDS AND LARGE HAIL.

..RACY.. 05/18/2010

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

ATTN...WFO...GLD...PUB...BOU...CYS...

LAT...LON   40240241 38650210 37840228 37240281 37200395 38200384
            38970441 39090449 39960464 40480493 41150508 41570602
            41990570 42140537 41870393 41260300 40240241

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 17, 6:23 PM MDT	Mesoscale Discussion	SPC	Bent, Crowley, Kiowa, Las Animas, Otero, Pueblo	67 min
May 17, 8:18 PM MDT	Mesoscale Discussion	SPC	Baca, Bent, Crowley, Kiowa, Las Animas, Otero and 2 more	87 min
May 18, 12:41 PM MDT	Tornado Watch	SPC	Adams, Arapahoe, Baca, Bent, Cheyenne, Crowley and 17 more	10 hr
May 18, 3:37 PM MDT	Mesoscale Discussion	SPC	Banner, Scotts Bluff, Sioux	83 min

Nearby

Mesoscale Discussions in Colorado, 2010 Mesoscale Discussions in Nebraska, 2010 Mesoscale Discussions in Wyoming, 2010 Every mesoscale discussion in 2010

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.