Alert archive / New York / Mesoscale Discussions in 2013

Mesoscale Discussion 113

February 2, 2013Jefferson County, New York

The Storm Prediction Center issued this mesoscale discussion at Feb 2, 2013, 10:55 AM EST for Jefferson County, New York. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued: Feb 2, 2013, 10:55 AM EST (15:55 UTC)
Expired: Feb 2, 2013, 5:00 PM EST
In force: 6 hr
Issued by: the Storm Prediction Center

County Jefferson County, NY

The radar

The Ft Drum radar (KTYX), 40 km from the middle of the area, began a volume at 15:59 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, 3.9 hours before the alert went out and 231 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: 952 m above ground
0-6 km bulk shear: 82 kt
0-1 km storm-relative helicity: 79 m²/s²
0-3 km storm-relative helicity: 209 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.

321 
ACUS11 KWNS 021555
SWOMCD
SPC MCD 021555 
NYZ000-022200-

MESOSCALE DISCUSSION 0113
NWS STORM PREDICTION CENTER NORMAN OK
0955 AM CST SAT FEB 02 2013

AREAS AFFECTED...JEFFERSON COUNTY NY INCLUDING THE WATERTOWN AREA

CONCERNING...HEAVY SNOW 

VALID 021555Z - 022200Z

SUMMARY...SNOW RATES OF 2 IN/HR ARE ANTICIPATED IN A LAKE EFFECT
SNOW BAND OVER JEFFERSON COUNTY NY THROUGH THE AFTERNOON...AFFECTING
THE WATERTOWN AREA.

DISCUSSION...BUF/TYX 0.5-DEGREE REFLECTIVITY DATA DEPICT A SHALLOW
REFLECTIVITY BAND BECOMING BETTER DEFINED OVER LAKE
ONTARIO...ORIENTED WSW-ENE. THIS BAND REPRESENTS A WAVY LAKE EFFECT
HEAVY SNOW BAND THAT EXTENDS DOWNWIND OF THE LAKESHORE INTO
JEFFERSON COUNTY NY...AND RECENT WATERTOWN OBS INDICATE MODERATE TO
HEAVY SNOW ONGOING. MESOSCALE ASCENT SUPPORTING THIS BAND EMANATES
FROM /1/ THE RELATIVELY LONG OVER-LAKE FETCH LENGTH CONTRIBUTING TO
MODESTLY DEEP CONVECTIVE BOUNDARY LAYERS -- REACHING 7-9 KFT PER
FORECAST SOUNDINGS -- AND /2/ WARM ADVECTION IN ADVANCE OF A
MID-LEVEL SHORTWAVE TROUGH MANIFESTED IN A WEAKLY VERTICALLY VEERING
WIND PROFILE WITHIN THE LOWEST 1.5 KM AGL PER BUF VWP. THE
ISALLOBARIC RESPONSE TO PRESSURE FALLS DRIVEN BY THE WARM ADVECTION
WILL YIELD A TENDENCY FOR THE SNOW BAND TO GRADUALLY SHIFT NWD
TOWARD THE ST. LAWRENCE RIVER THROUGH MID-AFTERNOON.
THEREAFTER...SLIGHT LOW-LEVEL VEERING SHOULD PROMOTE A SWD
PROGRESSION OF THE BAND BY LATE THIS AFTERNOON. THESE
CHARACTERISTICS ARE ILLUSTRATED BY THE CONSENSUS AMONGST
HIGH-RESOLUTION WRF GUIDANCE...WHICH SUGGESTS THAT 2-IN/HR SNOW
RATES WILL BE LIKELY...MAINLY IMPACTING JEFFERSON COUNTY.

..COHEN/CARBIN.. 02/02/2013

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

ATTN...WFO...BUF...

LAT...LON   44097630 44187614 44177592 44077577 43897582 43767593
            43737615 43827631 44097630

Nearby

Mesoscale Discussions in New York, 2013 Every mesoscale discussion in 2013

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.