Alert archive / New York / Mesoscale Discussions in 2018

Mesoscale Discussion 1513

October 2, 201811 counties in New York

The Storm Prediction Center issued this mesoscale discussion at Oct 2, 2018, 4:05 PM EDT for 11 counties in New York. It was in force for 115 min.

The area

The outline as issued.

The facts

Issued
Oct 2, 2018, 4:05 PM EDT (20:05 UTC)
Expired
Oct 2, 2018, 6:00 PM EDT
In force
115 min
Issued by
the Storm Prediction Center
Chance of a watch
40%

Counties Allegany County, NY, Cattaraugus County, NY, Chautauqua County, NY, Erie County, NY, Livingston County, NY, Ontario County, NY, Schuyler County, NY, Seneca County, NY, Steuben County, NY, Wyoming County, NY, Yates County, NY

The radar

The Buffalo radar (KBUF), 65 km from the middle of the area, began a volume at 20:06 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, 8.1 hours before the alert went out and 62 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 2018-10-02Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 13 joules per kilogram.LCLLFCEL10008507005003002001001 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 2018-10-02The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 205 square meters per square second.193958Sfc1 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
13 J/kg
Mixed-layer CIN
-93 J/kg
Mixed-layer LCL
476 m above ground
0-6 km bulk shear
49 kt
0-1 km storm-relative helicity
205 m²/s²
0-3 km storm-relative helicity
232 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2

Open this sounding in Storm Lab

The text

As transmitted.

002 
ACUS11 KWNS 022006
SWOMCD
SPC MCD 022005 
NYZ000-022200-

Mesoscale Discussion 1513
NWS Storm Prediction Center Norman OK
0305 PM CDT Tue Oct 02 2018

Areas affected...Western New York

Concerning...Severe potential...Watch possible 

Valid 022005Z - 022200Z

Probability of Watch Issuance...40 percent

SUMMARY...A few rotating storms have been recently noted in western
NY on KBUF radar. A WW may be needed if these trends continue.

DISCUSSION...Storms near a diffuse surface boundary along the NY/PA
border have shown an increase in low/mid-level rotation over the
course of the last hour on KBUF radar imagery. Given the favorable
deep layer shear of 45-50 kts and KBUF VAD showing near 200 m2/s2
0-3 km SRH, conditions are favorable for possible tornado
development with any of the stronger storms that can develop. The
main source of uncertainty is how much instability is present. A
general area of broken cirrus clouds over portions of central NY has
allowed temperatures to rise to the low 70s in a few locations --
potentially yielding 500-1000 J/kg MLCAPE. These areas will continue
to be monitored for possible tornado watch issuance should
conditions for rotating storms continue to increase.

..Wendt/Guyer.. 10/02/2018

...Please see www.spc.noaa.gov for graphic product...

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

LAT...LON   42867869 42957820 42917687 42607666 42327684 42087741
            42167827 42167926 42437954 42857903 42867869

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Oct 2, 2:55 PM EDTTornado WatchSPCSullivan8 hr
Oct 2, 3:10 PM EDTMesoscale DiscussionSPCBronx, Dutchess, Kings, New York, Orange, Putnam and 3 more2 hr
Oct 2, 4:43 PM EDTMesoscale DiscussionSPCSullivan2 hr
Oct 2, 4:57 PM EDTTornado WatchSPCDutchess, Orange, Putnam, Rockland, Ulster, Westchester7 hr
Oct 2, 7:24 PM EDTMesoscale DiscussionSPCDutchess, Orange, Putnam, Rockland, Sullivan, Westchester81 min

Nearby

Mesoscale Discussions in New York, 2018Every mesoscale discussion in 2018

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.