Alert archive / Pennsylvania / Mesoscale Discussions in 2011
Mesoscale Discussion 652
The Storm Prediction Center issued this mesoscale discussion at Apr 28, 2011, 2:20 AM EDT for 19 counties in New York; 37 counties in Pennsylvania. It was in force for 55 min.
The area
The outline as issued.
The facts
- Issued
- Apr 28, 2011, 2:20 AM EDT (06:20 UTC)
- Expired
- Apr 28, 2011, 3:15 AM EDT
- In force
- 55 min
- Issued by
- the Storm Prediction Center
All 56 counties
Broome County, NY, Chemung County, NY, Chenango County, NY, Cortland County, NY, Delaware County, NY, Fulton County, NY, Greene County, NY, Hamilton County, NY, Herkimer County, NY, Madison County, NY, Montgomery County, NY, Oneida County, NY, Onondaga County, NY, Otsego County, NY, Schenectady County, NY, Schoharie County, NY, Sullivan County, NY, Tioga County, NY, Tompkins County, NY, Adams County, PA, Bedford County, PA, Berks County, PA, Blair County, PA, Bradford County, PA, Carbon County, PA, Centre County, PA, Clinton County, PA, Columbia County, PA, Cumberland County, PA, Dauphin County, PA, Franklin County, PA, Fulton County, PA, Huntingdon County, PA, Juniata County, PA, Lackawanna County, PA, Lancaster County, PA, Lebanon County, PA, Lehigh County, PA, Luzerne County, PA, Lycoming County, PA, Mifflin County, PA, Monroe County, PA, Montour County, PA, Northampton County, PA, Northumberland County, PA, Perry County, PA, Pike County, PA, Schuylkill County, PA, Snyder County, PA, Sullivan County, PA, Susquehanna County, PA, Tioga County, PA, Union County, PA, Wayne County, PA, Wyoming County, PA, York County, PA
The radar
The Binghamton radar (KBGM), 58 km from the middle of the area, began a volume at 06:22 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
Albany, NY (KALY), launched 00:00Z, 6.3 hours before the alert went out and 215 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
- 108 J/kg
- Mixed-layer CIN
- -95 J/kg
- Mixed-layer LCL
- 777 m above ground
- 0-6 km bulk shear
- 41 kt
- 0-1 km storm-relative helicity
- 307 m²/s²
- 0-3 km storm-relative helicity
- 401 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 2.8
The text
As transmitted, in the capitals the NWS used until 2016.
456
ACUS11 KWNS 280621
SWOMCD
SPC MCD 280620
NYZ000-NJZ000-PAZ000-MDZ000-280715-
MESOSCALE DISCUSSION 0652
NWS STORM PREDICTION CENTER NORMAN OK
0120 AM CDT THU APR 28 2011
AREAS AFFECTED...CNTRL/ERN PA/NY
CONCERNING...SEVERE THUNDERSTORM WATCH 244...246...
VALID 280620Z - 280715Z
THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH
244...246...CONTINUES.
AS OF 0610Z...TSTMS HAVE EVOLVED INTO LARGELY A N/S-ORIENTED
CLUSTER/BROKEN LINES WITH EMBEDDED SUPERCELL STRUCTURES FROM TIOGA
COUNTY NY TO FULTON COUNTY PA. DOWNSTREAM AIR MASS DESTABILIZATION
CONTINUES AS A VERY STRONG S/SWLY LLJ TRANSPORTS A RICH WARM THETA-E
AIR MASS OVER THE MID-ATLANTIC. WITH SURFACE DEW POINTS IN THE
MIDDLE 60S FIRMLY ENTRENCHED...THREATS FOR ISOLATED DAMAGING
WINDS/TORNADOES WILL PERSIST GIVEN 0-1 KM SHEAR OF 40-50 KT. IF
RADAR SIGNATURES APPEAR TO STRENGTHEN FURTHER...AN UPGRADE TO A
TORNADO WATCH MAY BECOME NECESSARY.
..GRAMS.. 04/28/2011
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...OKX...ALY...PHI...BGM...BUF...CTP...LWX...
LAT...LON 39887875 41767754 43207609 43737515 43727458 43607428
43217408 42737401 42047421 40627529 39747619 39647732
39757860 39887875SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 27, 8:15 PM EDT | Severe Thunderstorm Watch | SPC | Albany, Broome, Chenango, Clinton, Cortland, Delaware and 19 more | 8 hr |
| Apr 27, 9:03 PM EDT | Mesoscale Discussion | SPC | Cayuga, Chemung, Tioga, Tompkins | 57 min |
| Apr 27, 10:45 PM EDT | Mesoscale Discussion | SPC | Albany, Broome, Chenango, Delaware, Essex, Franklin and 15 more | 60 min |
| Apr 28, 3:32 AM EDT | Mesoscale Discussion | SPC | Albany, Broome, Chenango, Delaware, Fulton, Greene and 15 more | 28 min |
| Apr 28, 4:05 AM EDT | Severe Thunderstorm Watch | SPC | Albany, Broome, Chenango, Cortland, Delaware, Fulton and 13 more | 6 hr |
| Apr 28, 6:21 AM EDT | Mesoscale Discussion | SPC | Albany, Chenango, Columbia, Delaware, Dutchess, Fulton and 15 more | 54 min |
| Apr 28, 9:45 AM EDT | Severe Thunderstorm Watch | SPC | Albany, Bronx, Columbia, Dutchess, Fulton, Greene and 19 more | 6 hr |
| Apr 28, 11:49 AM EDT | Mesoscale Discussion | SPC | Albany, Bronx, Columbia, Delaware, Dutchess, Fulton and 22 more | 56 min |
| Apr 27, 11:50 PM EDT | Severe Thunderstorm Watch | SPC | Adams, Bedford, Blair, Cambria, Cameron, Centre and 26 more | 7 hr |
Nearby
Mesoscale Discussions in Pennsylvania, 2011Mesoscale Discussions in New York, 2011Every mesoscale discussion in 2011
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.