Alert archive / New York / Mesoscale Discussions in 2012

Mesoscale Discussion 181

February 29, 2012Berkshire County, Hampden County, Hampshire County, Massachusetts; 18 counties in New York; Susquehanna County, Wayne County, Pennsylvania

The Storm Prediction Center issued this mesoscale discussion at Feb 29, 2012, 11:05 AM EST for Berkshire County, Hampden County, Hampshire County, Massachusetts; 18 counties in New York; Susquehanna County, Wayne County, Pennsylvania. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued: Feb 29, 2012, 11:05 AM EST (16:05 UTC)
Expired: Feb 29, 2012, 3:00 PM EST
In force: 4 hr
Issued by: the Storm Prediction Center

All 23 counties

Berkshire County, MA, Hampden County, MA, Hampshire County, MA, Albany County, NY, Broome County, NY, Chenango County, NY, Columbia County, NY, Cortland County, NY, Delaware County, NY, Dutchess County, NY, Greene County, NY, Madison County, NY, Montgomery County, NY, Orange County, NY, Otsego County, NY, Rensselaer County, NY, Schenectady County, NY, Schoharie County, NY, Sullivan County, NY, Tioga County, NY, Ulster County, NY, Susquehanna County, PA, Wayne County, PA

The radar

The Albany radar (KENX), 48 km from the middle of the area, began a volume at 16:07 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, 4.1 hours before the alert went out and 71 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: 969 m above ground
0-6 km bulk shear: 69 kt
0-1 km storm-relative helicity: 163 m²/s²
0-3 km storm-relative helicity: 367 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.

777 
ACUS11 KWNS 291606
SWOMCD
SPC MCD 291605
MAZ000-CTZ000-NYZ000-PAZ000-292000-

MESOSCALE DISCUSSION 0181
NWS STORM PREDICTION CENTER NORMAN OK
1005 AM CST WED FEB 29 2012

AREAS AFFECTED...SERN/S-CNTRL NY...WRN CT...WRN MA...FAR NERN PA

CONCERNING...WINTER MIXED PRECIPITATION

VALID 291605Z - 292000Z

MIXED WINTER PRECIP IS EXPECTED TO OCCUR THIS AFTERNOON ACROSS
SERN/S-CNTRL NY...WRN CT...WRN MA...AND FAR NERN PA...INCLUDING
AREAS WITH SNOW RATES TO 1 IN/HR AND FREEZING RAIN RATES OF 0.05
IN/HR.

STRONG WAA PER 12Z 850- AND 700-MB UPPER AIR ANALYSES IS SUPPORTING
A BROAD SHIELD OF STRATIFORM PRECIP ACROSS WRN NY AND PA...WHICH IS
FORECAST TO SHIFT NEWD FOR THE REMAINDER OF THIS MORNING INTO THIS
AFTERNOON. AS THE PRECIPITATION MOVES ATOP THE SUB-FREEZING SFC
LAYER /SUPPORTED IN SOME AREAS BY WET-BULBING EFFECTS/...A MIX OF
WINTER PRECIP TYPES WILL OCCUR. INITIALLY...THE COLUMN IS FORECAST
TO BE SUFFICIENTLY COLD FOR MAINLY SNOW...WITH RATES LOCALLY
REACHING 1 IN/HR...PARTICULARLY OVER THE CATSKILL MOUNTAINS AND THE
LOWER HUDSON RIVER VALLEY REGION AFTER 17Z. THIS IS AFFIRMED BY THE
BULK OF SHORT-TERM MODEL FORECAST SOUNDINGS AND EXPERIMENTAL SPC
SSEO GUIDANCE. A NEARLY ISOTHERMAL PROFILE CENTERED AROUND -3C TO
-1C BETWEEN THE 930 MB AND 650 MB LEVELS WILL PROMOTE EFFICIENT SNOW
AGGREGATION PROCESSES.

AFTER 19Z...THE PRECIP TYPE WILL LIKELY TRANSITION TO SLEET AND
FREEZING RAIN FROM SOUTH TO NORTH...AS TEMPERATURES WITHIN THE
ELEVATED WARM LAYER BETWEEN 850-700 MB INCREASE OWING TO CONTINUING
WAA ALOFT. FREEZING RAIN RATES OF 0.05 IN/HR WILL BE POSSIBLE...AND
THIS WILL BE OF GREATEST CONCERN IN SHELTERED VALLEYS WHERE SFC
TEMPERATURES HOLD AOB FREEZING. A COMPLETE TRANSITION TO RAIN MAY
OCCUR ACROSS FAR NERN PA AND FAR SERN NY BY LATE AFTERNOON IN AREAS
WHERE SFC WAA IS SUFFICIENT TO INCREASE THE SFC TEMPS TO ABOVE 32F.

..COHEN.. 02/29/2012

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

ATTN...WFO...BOX...OKX...ALY...BGM...

LAT...LON   42867360 42397257 41677274 41407390 41397491 41787620
            42297652 42847614 43127542 43107442 42867360

Nearby

Mesoscale Discussions in New York, 2012 Mesoscale Discussions in Massachusetts, 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.