Alert archive / Massachusetts / Mesoscale Discussions in 2017

Mesoscale Discussion 1743

October 24, 20179 counties in Massachusetts; Suffolk County, New York; 5 counties in Rhode Island

The Storm Prediction Center issued this mesoscale discussion at Oct 24, 2017, 8:55 PM EDT for 9 counties in Massachusetts; Suffolk County, New York; 5 counties in Rhode Island. It was in force for 65 min.

The area

The outline as issued.

The facts

Issued
Oct 24, 2017, 8:55 PM EDT (00:55 UTC)
Expired
Oct 24, 2017, 10:00 PM EDT
In force
65 min
Issued by
the Storm Prediction Center
Chance of a watch
20%

Counties Barnstable County, MA, Bristol County, MA, Dukes County, MA, Middlesex County, MA, Nantucket County, MA, Norfolk County, MA, Plymouth County, MA, Suffolk County, MA, Worcester County, MA, Suffolk County, NY, Bristol County, RI, Kent County, RI, Newport County, RI, Providence County, RI, Washington County, RI

The radar

The Brookhaven radar (KOKX), 47 km from the middle of the area, began a volume at 00:57 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

Brookhaven, NY (KOKX), launched 00:00Z, 0.9 hours before the alert went out and 47 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, Brookhaven, NY at 00:00Z on 2017-10-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 473 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, Brookhaven, NY at 00:00Z on 2017-10-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 248 square meters per square second.19395878Sfc1 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
473 J/kg
Mixed-layer CIN
-27 J/kg
Mixed-layer LCL
604 m above ground
0-6 km bulk shear
42 kt
0-1 km storm-relative helicity
248 m²/s²
0-3 km storm-relative helicity
290 m²/s²
Significant tornado parameter
0.5
Supercell composite
3.3

Open this sounding in Storm Lab

The text

As transmitted.

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Nearby

Mesoscale Discussions in Massachusetts, 2017Mesoscale Discussions in Connecticut, 2017Mesoscale Discussions in Rhode Island, 2017Every mesoscale discussion in 2017

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.