Alert archive / Oklahoma / Mesoscale Discussions in 2012
Mesoscale Discussion 848
The Storm Prediction Center issued this mesoscale discussion at May 20, 2012, 3:00 AM CDT for 8 counties in Oklahoma. It was in force for 90 min.
The area
The outline as issued.
The facts
- Issued
- May 20, 2012, 3:00 AM CDT (08:00 UTC)
- Expired
- May 20, 2012, 4:30 AM CDT
- In force
- 90 min
- Issued by
- the Storm Prediction Center
Counties Caddo County, OK, Cleveland County, OK, Grady County, OK, Kiowa County, OK, McClain County, OK, Okfuskee County, OK, Pottawatomie County, OK, Seminole County, OK
The radar
The Norman radar (KTLX), 20 km from the middle of the area, began a volume at 08:00 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 nearest sounding before it
Norman, OK (KOUN), launched 00:00Z, 8.0 hours before the alert went out and 5 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
- 539 J/kg
- Mixed-layer CIN
- -464 J/kg
- Mixed-layer LCL
- 1944 m above ground
- 0-6 km bulk shear
- 40 kt
- 0-1 km storm-relative helicity
- 211 m²/s²
- 0-3 km storm-relative helicity
- 337 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
374
ACUS11 KWNS 200801
SWOMCD
SPC MCD 200800
OKZ000-200930-
MESOSCALE DISCUSSION 0848
NWS STORM PREDICTION CENTER NORMAN OK
0300 AM CDT SUN MAY 20 2012
AREAS AFFECTED...PORTIONS OF CNTRL OK
CONCERNING...HEAVY RAINFALL
VALID 200800Z - 200930Z
SUMMARY...TRAINING CONVECTION WILL BE ASSOCIATED WITH A THREAT FOR
HEAVY RAIN...INCLUDING RAINFALL RATES TO 2 IN/HR...ACROSS A NARROW
W-E CORRIDOR IN CNTRL OK.
DISCUSSION...WAA NORTH OF A CONVECTIVELY AUGMENTED BOUNDARY LYING
ACROSS SRN OK WILL CONTINUE TO SUPPORT CONVECTIVE BACKBUILDING
WITHIN A 35-MILE CORRIDOR EXTENDING FROM KIOWA COUNTY EWD THROUGH
GRADY/CLEVELAND COUNTIES AND FARTHER EAST INTO OKFUSKEE/HUGHES
COUNTIES. THE STRONG WAA PATTERN IS REVEALED BY FREDERICK OK VWP
DATA...WITH WINDS ABRUPTLY VEERING FROM SELY TO WLY FROM THE SFC TO
3 KM...WITH A NOTABLE NOCTURNAL BOUNDARY LAYER WIND MAX OF SSWLY AT
40 KT AROUND 1 KM AGL. SLOPED MOISTURE TRANSPORT/ISENTROPIC ASCENT
ATOP THIS BOUNDARY WILL MAINTAIN CONVECTIVE TRAINING FOR THE NEXT
HOUR OR TWO...AS MESO-BETA ELEMENTS ARE STEERED EWD/ENEWD BY 20-35
KT OF CLOUD-LAYER FLOW PARALLEL TO THE AFOREMENTIONED BOUNDARY.
COLUMNAR SATURATION/LOW LCLS -- OWING TO EARLY CONVECTION -- WILL
SUPPORT HIGH PRECIPITATION EFFICIENCY AMIDST PW VALUES EXCEEDING 1.2
INCHES PER GPS DATA. RAINFALL RATES TO 2 IN/HR WILL BE OF CONCERN AS
STORMS REPEATEDLY MOVE OVER THE SAME LOCATIONS. THE THREAT FOR HEAVY
RAINFALL WILL LIKELY DIMINISH/SHIFT SEWD AFTER 10Z...AS A DEEPER
BOUNDARY/COLD FRONT ACROSS NWRN/N-CNTRL OK UNDERCUTS ONGOING
CONVECTION WHILE MOVING SEWD.
..COHEN.. 05/20/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...TSA...OUN...
LAT...LON 35419606 35219610 34989675 34879772 34829880 34919903
35199883 35339805 35319747 35539637 35419606SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 19, 7:03 PM CDT | Mesoscale Discussion | SPC | Alfalfa, Grant | 57 min |
| May 19, 9:03 PM CDT | Severe Thunderstorm Watch | SPC | Alfalfa, Beckham, Blaine, Caddo, Canadian, Comanche and 21 more | 7 hr |
| May 19, 11:09 PM CDT | Mesoscale Discussion | SPC | Blaine, Caddo, Canadian, Comanche, Garfield, Grady and 16 more | 66 min |
| May 20, 1:30 AM CDT | Mesoscale Discussion | SPC | Caddo, Canadian, Cleveland, Comanche, Creek, Garvin and 14 more | 90 min |
Nearby
Mesoscale Discussions in Oklahoma, 2012Every 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.