Alert archive / Pennsylvania / Mesoscale Discussions in 2012

Mesoscale Discussion 1013

June 1, 20129 counties in New York; 16 counties in Pennsylvania

The Storm Prediction Center issued this mesoscale discussion at Jun 1, 2012, 5:46 PM EDT for 9 counties in New York; 16 counties in Pennsylvania. It was in force for 89 min.

The area

The outline as issued.

The facts

Issued
Jun 1, 2012, 5:46 PM EDT (21:46 UTC)
Expired
Jun 1, 2012, 7:15 PM EDT
In force
89 min
Issued by
the Storm Prediction Center
Chance of a watch
60%
All 25 counties

Allegany County, NY, Cattaraugus County, NY, Chautauqua County, NY, Erie County, NY, Genesee County, NY, Livingston County, NY, Niagara County, NY, Steuben County, NY, Wyoming County, NY, Cameron County, PA, Centre County, PA, Clearfield County, PA, Clinton County, PA, Elk County, PA, Forest County, PA, Jefferson County, PA, Lycoming County, PA, McKean County, PA, Montour County, PA, Northumberland County, PA, Potter County, PA, Snyder County, PA, Tioga County, PA, Union County, PA, Warren County, PA

The radar

The State College radar (KCCX), 108 km from the middle of the area, began a volume at 21:46 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

Buffalo Intl Airport, NY (KBUF), launched 12:00Z, 9.8 hours before the alert went out and 123 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, Buffalo Intl Airport, NY at 12:00Z on 2012-06-01Temperature 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, Buffalo Intl Airport, NY at 12:00Z on 2012-06-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 379 square meters per square second.1939587897Sfc1 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
1119 m above ground
0-6 km bulk shear
36 kt
0-1 km storm-relative helicity
379 m²/s²
0-3 km storm-relative helicity
691 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.

505 
ACUS11 KWNS 012147
SWOMCD
SPC MCD 012146
PAZ000-NYZ000-012315-

MESOSCALE DISCUSSION 1013
NWS STORM PREDICTION CENTER NORMAN OK
0446 PM CDT FRI JUN 01 2012

AREAS AFFECTED...N CNTRL PA INTO WRN NY

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 012146Z - 012315Z

PROBABILITY OF WATCH ISSUANCE...60 PERCENT

SUMMARY...A FEW SEVERE STORMS MAY PERSIST NE OF WW 332...AND
ADDITIONAL CONSOLIDATION OF THE LINE MAY OCCUR AS WELL...EVENTUALLY
AFFECTING WRN NY. DAMAGING WINDS AND A FEW EMBEDDED AREAS OF
ROTATION WILL BE POSSIBLE.

DISCUSSION...WEAK INSTABILITY CURRENTLY EXISTS OVER NRN PA...WITH
VERY LITTLE IN WRN NY. HOWEVER...A STRONG SLY LOW LEVEL JET WILL
COMBINE WITH COOLING ALOFT TO RESULT IN MARGINAL INSTABILITY
SUFFICIENT FOR AT LEAST ISOLATED SEVERE WEATHER INTO THIS EVENING.

THE SYNOPTIC COLD FRONT IS LIKELY ASSOCIATED WITH THE WEAK
CONVECTIVE LINE IN ERN OH...BUT SOME STABILIZATION HAS OCCURRED TO
THE E WITH A STRONGER LINE IN PROGRESS. WITH A NNEWD MOVING PRESSURE
RISE/FALL COUPLET...AND INCREASE SHEAR PROFILES...SOME BOWS OR LINE
SEGMENTS MAY REMAIN STRONG TO SEVERE THROUGH EVENING EVEN WITH
MINIMAL INSTABILITY. THE GREATEST THREAT AREA WILL BE OVER PA WHERE
STRONGER INSTABILITY WILL EXIST...WITH A LESSER THREAT TO THE N.

..JEWELL/CORFIDI.. 06/01/2012

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

ATTN...WFO...BGM...BUF...CTP...PBZ...

LAT...LON   40737892 41647936 42357961 43297910 43407872 42897789
            41947678 41127641 40677660 40737892

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jun 1, 12:29 PM EDTMesoscale DiscussionSPCFranklin, Fulton61 min
Jun 1, 1:03 PM EDTMesoscale DiscussionSPCAdams, Bedford, Fayette, Franklin, Fulton, Somerset and 1 more87 min
Jun 1, 1:28 PM EDTTornado WatchSPCAdams, Bedford, Blair, Cambria, Cumberland, Fayette and 8 more8 hr
Jun 1, 1:50 PM EDTTornado WatchSPCBerks, Dauphin, Lancaster, Lebanon, York7 hr
Jun 1, 3:35 PM EDTMesoscale DiscussionSPCAdams, Bedford, Blair, Cambria, Cumberland, Franklin and 6 more55 min
Jun 1, 3:49 PM EDTMesoscale DiscussionSPCChester, Delaware, Lancaster, Philadelphia, York56 min
Jun 1, 4:25 PM EDTMesoscale DiscussionSPCBerks, Chester, Delaware, Montgomery, Philadelphia65 min
Jun 1, 6:04 PM EDTTornado WatchSPCCameron, Centre, Clearfield, Clinton, Columbia, Elk and 10 more5 hr
Jun 1, 6:54 PM EDTMesoscale DiscussionSPCBerks, Chester, Dauphin, Lancaster, Lebanon, York2 hr

Nearby

Mesoscale Discussions in Pennsylvania, 2012Mesoscale Discussions in New York, 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.