Alert archive / New York / Mesoscale Discussions in 2012

Mesoscale Discussion 824

May 16, 201228 counties in New York; 4 counties in Pennsylvania; 11 counties in Vermont

The Storm Prediction Center issued this mesoscale discussion at May 16, 2012, 12:27 PM EDT for 28 counties in New York; 4 counties in Pennsylvania; 11 counties in Vermont. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: May 16, 2012, 12:27 PM EDT (16:27 UTC)
Expired: May 16, 2012, 2:30 PM EDT
In force: 2 hr
Issued by: the Storm Prediction Center
Chance of a watch: 95%

All 43 counties

Albany County, NY, Broome County, NY, Chemung County, NY, Chenango County, NY, Clinton County, NY, Columbia County, NY, Cortland County, NY, Delaware County, NY, Essex County, NY, Franklin County, NY, Fulton County, NY, Greene County, NY, Hamilton County, NY, Herkimer County, NY, Madison County, NY, Montgomery County, NY, Oneida County, NY, Otsego County, NY, Rensselaer County, NY, Saratoga County, NY, Schenectady County, NY, Schoharie County, NY, Sullivan County, NY, Tioga County, NY, Tompkins County, NY, Ulster County, NY, Warren County, NY, Washington County, NY, Bradford County, PA, Susquehanna County, PA, Wayne County, PA, Wyoming County, PA, Addison County, VT, Bennington County, VT, Chittenden County, VT, Franklin County, VT, Grand Isle County, VT, Lamoille County, VT, Orange County, VT, Orleans County, VT, Rutland County, VT, Washington County, VT, Windsor County, VT

The radar

The Albany radar (KENX), 60 km from the middle of the area, began a volume at 16:31 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.

Severe Thunderstorm Watch 280May 16, 1:20 PM EDT

The nearest sounding before it

Albany, NY (KALY), launched 12:00Z, 4.5 hours before the alert went out and 73 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: 304 J/kg
Mixed-layer CIN: -26 J/kg
Mixed-layer LCL: 484 m above ground
0-6 km bulk shear: 32 kt
0-1 km storm-relative helicity: 16 m²/s²
0-3 km storm-relative helicity: 56 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.

058 
ACUS11 KWNS 161627
SWOMCD
SPC MCD 161627 
VTZ000-MAZ000-NYZ000-PAZ000-161830-

MESOSCALE DISCUSSION 0824
NWS STORM PREDICTION CENTER NORMAN OK
1127 AM CDT WED MAY 16 2012

AREAS AFFECTED...MUCH OF CNTRL AND ERN NY...VT...NERN PA

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY 

VALID 161627Z - 161830Z

PROBABILITY OF WATCH ISSUANCE...95 PERCENT

SUMMARY...STORMS WILL DEVELOP ACROSS THE AREA OVER THE NEXT FEW
HOURS...POSSIBLY IN SEVERAL LOCATIONS AT ONCE. LARGE HAIL AND A FEW
DAMAGING WIND GUSTS ARE LIKELY.

DISCUSSION...VISIBLE IMAGERY SHOWS CU FIELDS EXPANDING OVER MUCH OF
THE AREA. THE FIRST IS ALONG THE COLD FRONT FROM NWRN PA INTO WRN
NY...BUT INSTABILITY IS CURRENTLY LOW WITH DEWPOINTS MIXING INTO THE
40S F. FARTHER E...ANOTHER BAND OF CLOUDS WAS PERSISTING FROM SRN
QUEBEC INTO NRN AND CNTRL NY...ON THE EDGE OF THE ADVANCING UPPER
VORT. THE THIRD AREA WAS OVER SERN NY AND VT...NEAR THE SURFACE
THETA-E AXIS WHERE MUCAPE WAS APPROACHING 1500-2000 J/KG.

WITH CONTINUED HEATING AND LITTLE CIN...STORMS WILL LIKELY FORM BY
18-19Z. THE STRONGEST FORCING WILL BE NEAR THE FRONT...BUT OTHER
STORMS MAY FORM FARTHER E IN THE INSTABILITY AXIS. WITH FAVORABLE
DEEP LAYER FLOW AND INCREASING SPEED SHEAR WITH HEIGHT...SUPERCELLS
WILL BE LIKELY CAPABLE OF LARGE HAIL...PERHAPS UP TO GOLF BALL SIZE.


A WIND THREAT WILL ALSO BE PRESENT...PERHAPS MORE WITH THE FRONTAL
ACTIVITY WHERE STORM MODE COULD BENEFIT FORM MERGED OUTFLOWS. THE
TORNADO THREAT SHOULD BE RELATIVELY LOW WITH WEAK FLOW IN THE LOWEST
2KM...BUT...WINDS WILL VEER WITH HEIGHT AND COULD RESULT IN A
WEAK...BRIEF SPIN-UP.

..JEWELL/HART.. 05/16/2012

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

ATTN...WFO...BTV...ALY...BGM...BUF...CTP...

LAT...LON   41787725 42467691 43027599 44177481 45037402 45077239
            44907202 44267222 43287253 42387333 41897365 41677450
            41587499 41427608 41597687 41787725

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 16, 1:18 PM EDT	Severe Thunderstorm Watch	SPC	Albany, Broome, Chemung, Chenango, Clinton, Columbia and 24 more	9 hr
May 16, 3:37 PM EDT	Mesoscale Discussion	SPC	Albany, Broome, Chemung, Chenango, Clinton, Columbia and 22 more	113 min
May 16, 6:36 PM EDT	Mesoscale Discussion	SPC	Columbia, Rensselaer	84 min

Nearby

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