Alert archive / Pennsylvania / Mesoscale Discussions in 2011

Mesoscale Discussion 63

February 1, 20115 states

The Storm Prediction Center issued this mesoscale discussion at Feb 1, 2011, 2:42 AM EST for 5 states. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued: Feb 1, 2011, 2:42 AM EST (07:42 UTC)
Expired: Feb 1, 2011, 6:45 AM EST
In force: 4 hr
Issued by: the Storm Prediction Center

All 73 counties

Berkshire County, MA, Bergen County, NJ, Hunterdon County, NJ, Morris County, NJ, Passaic County, NJ, Somerset County, NJ, Sussex County, NJ, Warren County, NJ, Albany County, NY, Allegany County, NY, Broome County, NY, Chemung County, NY, Chenango County, NY, Columbia County, NY, Cortland County, NY, Delaware County, NY, Dutchess County, NY, Fulton County, NY, Greene County, NY, Madison County, NY, Montgomery County, NY, Orange County, NY, Otsego County, NY, Putnam County, NY, Rensselaer County, NY, Rockland County, NY, Saratoga County, NY, Schenectady County, NY, Schoharie County, NY, Schuyler County, NY, Steuben County, NY, Sullivan County, NY, Tioga County, NY, Tompkins County, NY, Ulster County, NY, Yates County, NY, Berks County, PA, Blair County, PA, Bradford County, PA, Cameron County, PA, Carbon County, PA, Centre County, PA, Clearfield County, PA, Clinton County, PA, Columbia County, PA, Cumberland County, PA, Dauphin County, PA, Elk County, PA, Huntingdon County, PA, Juniata County, PA, Lackawanna County, PA, Lebanon County, PA, Lehigh County, PA, Luzerne County, PA, Lycoming County, PA, McKean County, PA, Mifflin County, PA, Monroe County, PA, Montour County, PA, Northampton County, PA, Northumberland County, PA, Perry County, PA, Pike County, PA, Potter 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, Bennington County, VT

The radar

The Binghamton radar (KBGM), 52 km from the middle of the area, began a volume at 07:45 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

Albany, NY (KALY), launched 00:00Z, 7.7 hours before the alert went out and 190 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 1833 m above ground
0-6 km bulk shear: 69 kt
0-1 km storm-relative helicity: -4 m²/s²
0-3 km storm-relative helicity: 197 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.

310 
ACUS11 KWNS 010743
SWOMCD
SPC MCD 010742
MAZ000-CTZ000-VTZ000-NYZ000-NJZ000-PAZ000-011145-

MESOSCALE DISCUSSION 0063
NWS STORM PREDICTION CENTER NORMAN OK
0142 AM CST TUE FEB 01 2011

AREAS AFFECTED...SRN TIER OF NY...CNTRL/NRN PA...NRN NJ AND WRN NEW
ENGLAND

CONCERNING...WINTER MIXED PRECIPITATION

VALID 010742Z - 011145Z

MID-LEVEL IMPULSE CONTINUES TO ADVANCE QUICKLY EWD INTO THE LOWER
GREAT LAKES REGION THIS MORNING.  SSWLY LLJ ATTENDANT TO THIS SYSTEM
WILL DEVELOP EWD FROM THE OH VLY INTO THE MID-ATLANTIC
REGION...ENHANCING A BROAD BAND OF PCPN.  THIS PCPN SHIELD SHOULD
INTENSIFY FROM CNTRL/NRN PA ENE TOWARD SRN NEW ENGLAND THROUGH 12Z.

21Z SREF/05Z RUC APPEAR TO IDENTIFY THE DEVELOPING PCPN WELL.  WHILE
MESOSCALE BANDING POTENTIAL IS LOW WITH THIS EVENT...THE NRN EDGE OF
PCPN...LIKELY ALL SNOW WITH 15-12:1 RATIOS...WILL FALL AT RATES
AROUND 1 INCH PER HOUR WITHIN 40-45 NM OF THE PA/NY BORDER INTO WRN
NEW ENGLAND.  MOST INTENSE SNOWFALL RATES SHOULD PEAK 12-15Z AND
DIMINISH BY 18Z.

MEANWHILE...SNOW WILL LIKELY MIX WITH SLEET AND FREEZING RAIN
FARTHER TO THE SOUTH FROM CNTRL PA EWD INTO NWRN NJ AND THE LOWER
HUDSON VALLEY THROUGH MID-MORNING AS 800-850 MB TEMPERATURES RISE TO
2-3 DEG C WHILE MAINTAINING SUB-FREEZING NEAR-SURFACE LAYER WITHIN
COLD WEDGE.  21Z SREF INDICATES A HIGH PROBABILITY OF GREATER THAN
0.05" OF WATER EQUIV IN 3-HOURS WITHIN A 60 MILE CORRIDOR CENTERED
30 SE KDJU-40 WNW KABE-NEAR KPOU.  RUC GUIDANCE SUGGESTS HOURLY
RATES COULD EASILY EXCEED A TENTH OF AN INCH PER HOUR...ESP AFTER
12Z.

..RACY.. 02/01/2011

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

ATTN...WFO...BOX...OKX...ALY...PHI...BGM...BUF...CTP...PBZ...

LAT...LON   42447836 42797644 43217413 43137317 42687277 42187270
            41617311 41167375 40507466 40297568 40097702 40467846
            41477898 41977901 42447836

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Feb 1, 12:12 AM EST	Mesoscale Discussion	SPC	Allegheny, Armstrong, Beaver, Butler, Clarion, Crawford and 10 more	5 hr

Nearby

Mesoscale Discussions in Pennsylvania, 2011 Mesoscale Discussions in New York, 2011 Mesoscale Discussions in New Jersey, 2011 Every 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.