Alert archive / New York / Mesoscale Discussions in 2014

Mesoscale Discussion 1925

November 18, 2014Erie County, Genesee County, Wyoming County, New York

The Storm Prediction Center issued this mesoscale discussion at Nov 18, 2014, 1:00 PM EST for Erie County, Genesee County, Wyoming County, New York. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued
Nov 18, 2014, 1:00 PM EST (18:00 UTC)
Expired
Nov 18, 2014, 5:00 PM EST
In force
4 hr
Issued by
the Storm Prediction Center

Counties Erie County, NY, Genesee County, NY, Wyoming County, NY

The radar

The Buffalo radar (KBUF), 32 km from the middle of the area, began a volume at 18:02 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

Buffalo Intl Airport, NY (KBUF), launched 12:00Z, 6.0 hours before the alert went out and 31 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-pSkew-T log-p diagram, Buffalo Intl Airport, NY at 12:00Z on 2014-11-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Buffalo Intl Airport, NY at 12:00Z on 2014-11-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 10 square meters per square second.1939587897117136Sfc1 km3 km6 km9 kmRMLM
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
747 m above ground
0-6 km bulk shear
71 kt
0-1 km storm-relative helicity
10 m²/s²
0-3 km storm-relative helicity
25 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.

573 
ACUS11 KWNS 181801
SWOMCD
SPC MCD 181800 
NYZ000-182200-

MESOSCALE DISCUSSION 1925
NWS STORM PREDICTION CENTER NORMAN OK
1200 PM CST TUE NOV 18 2014

AREAS AFFECTED...WRN NY STATE

CONCERNING...HEAVY SNOW 

VALID 181800Z - 182200Z

SUMMARY...HEAVY SNOW RATES OF 3-4" PER HOUR WILL CONTINUE FOR NEXT
4-6 HOURS JUST S OF BUF.  A SWD SHIFT AND WEAKENING OF THE BAND IS
EXPECTED TO BEGIN AFTER 00Z.

DISCUSSION...A STEADY LAKE-EFFECT SNOW BAND PERSISTS ALONG THE
LONG-AXIS ORIENTATION OF LAKE ERIE...INTO SUBURBAN AREAS IMMEDIATELY
S OF THE NEARLY PERFECT ALONG-LAKE FETCH AND WEAK VERTICAL SHEAR
BELOW 700 MB WILL MAINTAIN THE STRONG SNOW BAND FOR SEVERAL MORE
HOURS.VERY LARGE AIR-LAKE TEMPERATURE DIFFERENCES ARE DRIVING
INTENSE CONVECTIVE MIXING WITHIN THE LAKE PLUME...AS EVIDENCED BY
THE 30-40 KT WNW-NW SURFACE WINDS AND STRONG CONVERGENCE INTO THE
BAND OVER THE NE PART OF LAKE ERIE.  THERMAL PROFILES ARE MOST
FAVORABLE FOR THE DEEPEST CONVECTION NOW /AS EVIDENCED BY A FEW
LIGHTNING FLASHES IN THE PAST HOUR/...AND PROFILES SHOULD REMAIN
FAVORABLE THIS AFTERNOON.  NEAR OR AFTER 00Z...EQUILIBRIUM LEVELS
WILL LOWER AND THE DEPTH OF THE LAKE BAND WILL BEGIN TO
DIMINISH.....COINCIDENT WITH VEERING OF THE MIDLEVEL FLOW AND A
RESULTANT SWD SHIFT OF THE BAND AS A MIDLEVEL TROUGH PROGRESSES E OF
LAKE ERIE.  THUS...THE VERY HEAVY SNOWFALL RATES ARE EXPECTED TO
PERSIST FOR THE NEXT 4-6 HOURS IMMEDIATELY S OF BUF WHERE
EXCEPTIONAL SNOW TOTALS NEAR 4 FEET HAVE ALREADY BEEN OBSERVED.

..THOMPSON.. 11/18/2014

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

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

LAT...LON   42737933 42987867 43047830 42997790 42857782 42737798
            42617834 42507888 42427927 42327969 42357989 42537987
            42737933

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Nov 17, 8:49 PM ESTMesoscale DiscussionSPCErie, Genesee4 hr
Nov 18, 3:53 AM ESTMesoscale DiscussionSPCJefferson, Lewis6 hr
Nov 18, 6:26 PM ESTMesoscale DiscussionSPCChautauqua, Erie3 hr

Nearby

Mesoscale Discussions in New York, 2014Every mesoscale discussion in 2014

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.