Alert archive / Pennsylvania / Mesoscale Discussions in 2012
Mesoscale Discussion 681
The Storm Prediction Center issued this mesoscale discussion at May 3, 2012, 5:45 PM EDT for Washington County, Maryland; Allegany County, New York; 20 counties in Pennsylvania. It was in force for 60 min.
The area
The outline as issued.
The facts
- Issued
- May 3, 2012, 5:45 PM EDT (21:45 UTC)
- Expired
- May 3, 2012, 6:45 PM EDT
- In force
- 60 min
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 20%
All 22 counties
Washington County, MD, Allegany County, NY, Bradford County, PA, Cameron County, PA, Centre County, PA, Clinton County, PA, Columbia County, PA, Cumberland County, PA, Franklin County, PA, Fulton County, PA, Huntingdon County, PA, Juniata County, PA, Lycoming County, PA, Mifflin County, PA, Montour County, PA, Northumberland County, PA, Perry County, PA, Potter County, PA, Snyder County, PA, Sullivan County, PA, Tioga County, PA, Union County, PA
The radar
The State College radar (KCCX), 54 km from the middle of the area, began a volume at 21:49 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
Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 9.8 hours before the alert went out and 220 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 763 m above ground
- 0-6 km bulk shear
- 23 kt
- 0-1 km storm-relative helicity
- 141 m²/s²
- 0-3 km storm-relative helicity
- 159 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
275
ACUS11 KWNS 032145
SWOMCD
SPC MCD 032145
PAZ000-NYZ000-MDZ000-WVZ000-032245-
MESOSCALE DISCUSSION 0681
NWS STORM PREDICTION CENTER NORMAN OK
0445 PM CDT THU MAY 03 2012
AREAS AFFECTED...WRN NY...CNTRL PA
CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY
VALID 032145Z - 032245Z
PROBABILITY OF WATCH ISSUANCE...20 PERCENT
SUMMARY...A FEW STRONG TO SEVERE STORMS WILL CONTINUE ACROSS WRN NY
INTO CNTRL PA THIS EVENING...GENERALLY WEAKENING AFTER DARK. DUE TO
THE GENERALLY ISOLATED NATURE...A WW IS NOT ANTICIPATED.
DISCUSSION...THUNDERSTORMS APPEAR TO HAVE INITIATED IN RESPONSE TO
THE WRN EDGE OF YESTERDAYS EXITING UPPER DISTURBANCE...AND A SUBTLE
WAVE NOW LOCATED ON 2130Z WV IMAGERY OVER WRN NY AND N CNTRL PA.
SEASONABLY WARM TEMPERATURES AND A MOIST AIR MASS CHARACTERIZED BY
SURFACE DEW POINTS IN THE 60S IN COMBINATION WITH COOLER
TEMPERATURES ALOFT ARE SUPPORTING OCCASIONALLY STRONG
UPDRAFTS...GENERALLY OVER THE HIGHER TERRAIN OF CNTRL PA.
HOWEVER...DEEP LAYER WINDS REMAIN WEAK...SUPPORTING MAINLY PULSE
TYPE STORMS AND SMALL CLUSTERS. A SEMI-ORGANIZED COLD POOL APPEARS
TO BE DEVELOPING IN CNTRL PA...WHICH MAY FAVOR DMGG WIND GUSTS AND
NEAR SEVERE HAIL AS IT ARCS TO THE SSE TOWARDS GREATER INSTABILITY.
ATTM...LIMITED COVERAGE OF SEVERE STORMS WILL PRECLUDE A WW
ISSUANCE. STORMS ARE EXPECTED TO WEAKEN AFTER THE ONSET OF DIURNAL
COOLING.
..HURLBUT/THOMPSON.. 05/03/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...BGM...BUF...CTP...LWX...
LAT...LON 42407786 41977640 41277615 40697658 39567746 39547822
40577823 42087828 42407786Nearby
Mesoscale Discussions in Pennsylvania, 2012Mesoscale Discussions in Maryland, 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.