Alert archive / New Mexico / Mesoscale Discussions in 2012

Mesoscale Discussion 857

May 21, 20124 states

The Storm Prediction Center issued this mesoscale discussion at May 21, 2012, 11:59 AM MDT for 4 states. It was in force for 91 min.

The area

The outline as issued.

The facts

Issued: May 21, 2012, 11:59 AM MDT (17:59 UTC)
Expired: May 21, 2012, 1:30 PM MDT
In force: 91 min
Issued by: the Storm Prediction Center
Chance of a watch: 80%

All 21 counties

Baca County, CO, Las Animas County, CO, Colfax County, NM, Curry County, NM, De Baca County, NM, Guadalupe County, NM, Harding County, NM, Mora County, NM, Quay County, NM, Roosevelt County, NM, San Miguel County, NM, Union County, NM, Cimarron County, OK, Bailey County, TX, Castro County, TX, Dallam County, TX, Deaf Smith County, TX, Hartley County, TX, Moore County, TX, Oldham County, TX, Parmer County, TX

The radar

The Cannon AFB radar (KFDX), 167 km from the middle of the area, began a volume at 18:01 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

Severe Thunderstorm Watch 287May 21, 2:25 PM MDT

The nearest sounding before it

Amarillo Airport, TX (KAMA), launched 12:00Z, 6.0 hours before the alert went out and 177 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: 849 J/kg
Mixed-layer CIN: -54 J/kg
Mixed-layer LCL: 631 m above ground
0-6 km bulk shear: 32 kt
0-1 km storm-relative helicity: 60 m²/s²
0-3 km storm-relative helicity: 94 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 3.2

Open this sounding in Storm Lab

The text

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

245 
ACUS11 KWNS 211800
SWOMCD
SPC MCD 211759
OKZ000-TXZ000-COZ000-NMZ000-211930-

MESOSCALE DISCUSSION 0857
NWS STORM PREDICTION CENTER NORMAN OK
1259 PM CDT MON MAY 21 2012

AREAS AFFECTED...EXTREME SERN CO...NERN/E-CNTRL NM...WRN TX/OK
PANHANDLES

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY

VALID 211759Z - 211930Z

PROBABILITY OF WATCH ISSUANCE...80 PERCENT

SUMMARY...ISOLATED TO SCATTERED THUNDERSTORMS...INCLUDING A FEW
SUPERCELLS...ARE EXPECTED TO DEVELOP THIS AFTERNOON ACROSS PORTIONS
OF EXTREME SERN CO...NERN/E-CNTRL NM AND THE WRN TX/OK PANHANDLES.
LARGE HAIL AND DAMAGING WIND GUSTS WILL BE THE PRIMARY SVR WEATHER
THREATS. WW IS LIKELY.

DISCUSSION...VISIBLE SATELLITE IMAGERY SHOWS MORNING THUNDERSTORM
ACTIVITY HAS CLEARED THE TX PANHANDLE. IN ITS WAKE...SURFACE COLD
POOL IS EVIDENT IN 17Z SURFACE OBSERVATIONS /TEMPERATURES NEAR 70F
OVER THE PANHANDLE/...WITH AN OUTFLOW BOUNDARY ORIENTED ROUGHLY N-S
OVER FAR E-CNTRL NM. BACKED SURFACE WINDS ACROSS THE COOL SIDE OF
THE OUTFLOW BOUNDARY VEER TO SLY OVER NERN NM AND SERN CO...WHICH IS
AIDING IN MAINTAINING A RELATIVELY MOIST AIRMASS OVER THE SRN HIGH
PLAINS /DEWPOINTS IN THE MID 50S...MIXING RATIO VALUES FROM 9-11 G
PER KG/. GIVEN THE COMBINATION OF 700-500 MB LAPSE RATES FROM 7-8
C/KM AND MOIST/WARMING BOUNDARY LAYER...MLCAPE VALUES NEAR 1500 J/KG
ARE DEVELOPING ACROSS E-CNTRL INTO NERN NM. IN ADDITION...SURFACE
HEATING OVER THE SRN ROCKIES AND RATON MESA IS LEADING TO RAPIDLY
STEEPENING LOW-LEVEL LAPSE RATES...WHICH IS ENHANCING CUMULUS
GROWTH.

GIVEN THESE TRENDS...THUNDERSTORM INITIATION IS EXPECTED TO TAKE
PLACE DURING THE NEXT FEW HRS OVER THE HIGHER TERRAIN...AND THEN
SPREAD SEWD AS THE PLAINS CONTINUE TO DESTABILIZE. BOTH TCU PROFILER
DATA AND RAP FORECAST SOUNDINGS SHOW LOW-LEVEL S-SELYS VEERING TO
20-30 KT NWLY FLOW IN THE MIDLEVELS...WHICH WILL YIELD SUFFICIENT
VERTICAL WIND SHEAR FOR SUPERCELLS. THOUGH AN ISOLATED TORNADO WILL
BE POSSIBLE...PRIMARY SVR WEATHER THREATS WILL BE LARGE HAIL
/POSSIBLY VERY LARGE/ AND DAMAGING WIND GUSTS.

..GARNER/WEISS.. 05/21/2012

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

ATTN...WFO...LUB...AMA...PUB...ABQ...

LAT...LON   37490274 36960203 35670182 34110231 33930402 35100540
            36800495 37470392 37490274

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 21, 2:24 PM MDT	Severe Thunderstorm Watch	SPC	Colfax, Curry, De Baca, Guadalupe, Harding, Mora and 4 more	8 hr
May 21, 4:18 PM MDT	Mesoscale Discussion	SPC	Colfax, Curry, Harding, Mora, Quay, San Miguel and 1 more	87 min
May 20, 6:32 PM MDT	Mesoscale Discussion	SPC	Dickens, Haskell, Kent, King, Knox, Stonewall	88 min

Nearby

Mesoscale Discussions in New Mexico, 2012 Mesoscale Discussions in Texas, 2012 Mesoscale Discussions in Colorado, 2012 Every mesoscale discussion in 2012

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.