Alert archive / Pennsylvania / Mesoscale Discussions in 2012
Mesoscale Discussion 925
The Storm Prediction Center issued this mesoscale discussion at May 27, 2012, 4:12 PM EDT for 24 counties in Pennsylvania. It was in force for 63 min.
The area
The outline as issued.
The facts
- Issued
- May 27, 2012, 4:12 PM EDT (20:12 UTC)
- Expired
- May 27, 2012, 5:15 PM EDT
- In force
- 63 min
- Issued by
- the Storm Prediction Center
All 24 counties
Allegheny County, PA, Armstrong County, PA, Beaver County, PA, Blair County, PA, Butler County, PA, Cambria County, PA, Centre County, PA, Clarion County, PA, Clearfield County, PA, Clinton County, PA, Cumberland County, PA, Dauphin County, PA, Franklin County, PA, Huntingdon County, PA, Indiana County, PA, Jefferson County, PA, Juniata County, PA, Mifflin County, PA, Montour County, PA, Northumberland County, PA, Perry County, PA, Snyder County, PA, Union County, PA, Westmoreland County, PA
The radar
The State College radar (KCCX), 31 km from the middle of the area, began a volume at 20:16 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.
The nearest sounding before it
Pittsburgh, PA (KPIT), launched 12:00Z, 8.2 hours before the alert went out and 174 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
- 993 J/kg
- Mixed-layer CIN
- -88 J/kg
- Mixed-layer LCL
- 1085 m above ground
- 0-6 km bulk shear
- 16 kt
- 0-1 km storm-relative helicity
- 46 m²/s²
- 0-3 km storm-relative helicity
- 47 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
668
ACUS11 KWNS 272013
SWOMCD
SPC MCD 272012
PAZ000-272115-
MESOSCALE DISCUSSION 0925
NWS STORM PREDICTION CENTER NORMAN OK
0312 PM CDT SUN MAY 27 2012
AREAS AFFECTED...ERN OH...WRN PA
CONCERNING...SEVERE THUNDERSTORM WATCH 303...
VALID 272012Z - 272115Z
THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 303
CONTINUES.
SUMMARY...A LOOSELY ORGANIZED CLUSTER OF STORMS CONTINUES TO TRACK
ESEWD. STRONGER CELLS WILL BE CAPABLE OF HAIL AND DMGG WINDS. A NEW
WW MAY BE NEED TO BE COORDINATED DOWNSTREAM SOON. COUNTIES IN THE
WAKE OF THE MCS MAY BE CLEARED.
DISCUSSION...PER 20Z VISIBLE AND RADAR IMAGERY...THE MCS OVER NWRN
PA IS BECOMING SOMEWHAT BETTER DEFINED AS IT PROGRESSES ESEWD INTO
GREATER INSTABILITY. ALTHOUGH STRONGER DEEP-LAYER FLOW REMAINS TO
THE N...STEEP LOW-LEVEL LAPSE RATES NEAR 8 C/KM PER MESOANALYSIS MAY
LOCALLY ENHANCE DOWNBURST WINDS. HAIL REMAINS POSSIBLE WITH THE
STRONGER CORES. ADDITIONALLY...SEVERAL NWD PROGRESSING OUTFLOW
BOUNDARIES FROM THE CONVECTION TO THE S MAY LOCALLY ENHANCE SURFACE
CONVERGENCE AND/OR INITIATE NEW CONVECTION. ATTM...IT APPEARS THAT
THE MCS WILL BE SUSTAINED THROUGH CNTRL PA IN ADVANCE OF A WEAK
UPPER WAVE. HOWEVER...THE WIND THREAT MAY DIMINISH AFTER NOCTURNAL
COOLING BEGINS TO STABILIZE THE BOUNDARY LAYER.
..HURLBUT.. 05/27/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...CTP...PBZ...
LAT...LON 40087896 40608041 41128015 41457923 41277759 41117664
40857602 40587643 40067666 39927773 40087896SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 27, 12:56 PM EDT | Mesoscale Discussion | SPC | Armstrong, Beaver, Butler, Clarion, Crawford, Erie and 5 more | 64 min |
| May 27, 1:33 PM EDT | Severe Thunderstorm Watch | SPC | Allegheny, Armstrong, Beaver, Butler, Clarion, Crawford and 9 more | 5 hr |
| May 27, 1:41 PM EDT | Mesoscale Discussion | SPC | Allegheny, Bedford, Blair, Cambria, Cumberland, Fayette and 11 more | 64 min |
| May 27, 5:21 PM EDT | Severe Thunderstorm Watch | SPC | Adams, Bedford, Blair, Cambria, Centre, Clearfield and 21 more | 4 hr |
| May 27, 6:34 PM EDT | Mesoscale Discussion | SPC | Adams, Bedford, Blair, Cambria, Cumberland, Fayette and 9 more | 56 min |
Nearby
Mesoscale Discussions in Pennsylvania, 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.