Alert archive / Pennsylvania / Mesoscale Discussions in 2010

Mesoscale Discussion 1321

July 16, 20106 states

The Storm Prediction Center issued this mesoscale discussion at Jul 16, 2010, 1:23 PM EDT for 6 states. It was in force for 97 min.

The area

The outline as issued.

The facts

Issued: Jul 16, 2010, 1:23 PM EDT (17:23 UTC)
Expired: Jul 16, 2010, 3:00 PM EDT
In force: 97 min
Issued by: the Storm Prediction Center

All 53 counties

Berkshire County, MA, Franklin County, MA, Hampden County, MA, Hampshire County, MA, Franklin County, ME, Oxford County, ME, Belknap County, NH, Carroll County, NH, Cheshire County, NH, Coos County, NH, Grafton County, NH, Hillsborough County, NH, Merrimack County, NH, Sullivan County, NH, Albany County, NY, Broome County, NY, Columbia County, NY, Delaware County, NY, Dutchess County, NY, Greene County, NY, Orange County, NY, Rensselaer County, NY, Saratoga County, NY, Schenectady County, NY, Schoharie County, NY, Sullivan County, NY, Ulster County, NY, Washington County, NY, Bradford County, PA, Carbon County, PA, Columbia County, PA, Cumberland County, PA, Dauphin County, PA, Franklin County, PA, Juniata County, PA, Lackawanna County, PA, Luzerne County, PA, Lycoming County, PA, Monroe County, PA, Montour County, PA, Northumberland County, PA, Perry County, PA, Pike County, PA, Schuylkill County, PA, Snyder County, PA, Sullivan County, PA, Susquehanna County, PA, Union County, PA, Wayne County, PA, Wyoming County, PA, Bennington County, VT, Windham County, VT, Windsor County, VT

The radar

The Albany radar (KENX), 11 km from the middle of the area, began a volume at 17:25 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 12:00Z, 5.4 hours before the alert went out and 23 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: 72 J/kg
Mixed-layer CIN: -100 J/kg
Mixed-layer LCL: 914 m above ground
0-6 km bulk shear: 30 kt
0-1 km storm-relative helicity: 172 m²/s²
0-3 km storm-relative helicity: 167 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

427 
ACUS11 KWNS 161724
SWOMCD
SPC MCD 161723
MEZ000-NHZ000-MAZ000-VTZ000-CTZ000-NYZ000-NJZ000-PAZ000-161900-

MESOSCALE DISCUSSION 1321
NWS STORM PREDICTION CENTER NORMAN OK
1223 PM CDT FRI JUL 16 2010

AREAS AFFECTED...CNTRL THROUGH NERN PA...SERN NY...SRN VT...WRN MA
AND WRN ME

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 161723Z - 161900Z

STORMS WILL UNDERGO A GRADUAL INCREASE IN COVERAGE AND INTENSITY
THIS AFTERNOON FROM CNTRL AND NERN PA...SERN NY INTO A PORTION OF
NEW ENGLAND. SOME POTENTIAL WILL EXIST FOR ISOLATED STRONG WIND
GUSTS...BUT OVERALL THREAT DOES NOT APPEAR PARTICULARLY ROBUST.
TRENDS WILL CONTINUE TO BE MONITORED.

PRE-FRONTAL WARM SECTOR HAS BECOME MODERATELY UNSTABLE FROM CNTRL
AND ERN PA...SERN NY INTO NEW ENGLAND EAST OF MULTI-LAYER CLOUD BAND
ASSOCIATED WITH NEWD ADVECTING SUBTROPICAL MOIST PLUME. WEAK
MID-LEVEL LAPSE RATES AND WARM AIR ALOFT ARE LIMITING MLCAPE TO
GENERALLY AOB 1500 J/KG DESPITE STRONG DIABATIC WARMING OF THE MOIST
BOUNDARY LAYER AND RICH LOW-LEVEL MOISTURE. THE CAP IS WEAK...AND
STORMS WILL CONTINUE DEVELOPING WITHIN ZONE OF DIFFERENTIAL HEATING
ALONG FRINGE OF THE EXTENSIVE CLOUD PLUME AS WELL AS ALONG OTHER
PRE-FRONTAL BOUNDARIES AND TERRAIN FEATURES. WIND PROFILES ARE WLY
UNIDIRECTIONAL WITH BELT OF MODERATE 500 MB FLOW WITHIN BASE OF
ONTARIO UPPER TROUGH RESULTING IN 25-35 KT BULK SHEAR SUPPORTIVE OF
MULTICELLS. SUFFICIENT LOW-LEVEL LAPSE RATES AND INSTABILITY WILL
EXIST TO PROMOTE AT LEAST A MODEST THREAT FOR ISOLATED DOWNBURSTS
WITH THE STRONGER STORMS.

..DIAL.. 07/16/2010

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

ATTN...WFO...GYX...BOX...BTV...OKX...ALY...PHI...BGM...CTP...

LAT...LON   41537721 42487514 43767258 45207081 44826997 42287215
            39837781 41537721

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 16, 7:50 PM EDT	Mesoscale Discussion	SPC	Essex, Middlesex, Norfolk, Suffolk, Worcester	55 min

Nearby

Mesoscale Discussions in Pennsylvania, 2010 Mesoscale Discussions in New York, 2010 Mesoscale Discussions in New Hampshire, 2010 Every mesoscale discussion in 2010

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.