Alert archive / New York / Mesoscale Discussions in 2021

Mesoscale Discussion 898

June 9, 20214 states

The Storm Prediction Center issued this mesoscale discussion at Jun 9, 2021, 3:19 PM EDT for 4 states. It was in force for 116 min.

The area

The outline as issued.

The facts

Issued: Jun 9, 2021, 3:19 PM EDT (19:19 UTC)
Expired: Jun 9, 2021, 5:15 PM EDT
In force: 116 min
Issued by: the Storm Prediction Center
Concerning: Severe potential...watch unlikely
Chance of a watch: 5%

All 37 counties

Barnstable County, MA, Berkshire County, MA, Bristol County, MA, Dukes County, MA, Hampden County, MA, Hampshire County, MA, Middlesex County, MA, Norfolk County, MA, Plymouth County, MA, Suffolk County, MA, Worcester County, MA, Bergen County, NJ, Essex County, NJ, Hudson County, NJ, Passaic County, NJ, Sussex County, NJ, Albany County, NY, Bronx County, NY, Columbia County, NY, Dutchess County, NY, Greene County, NY, Kings County, NY, Nassau County, NY, New York County, NY, Orange County, NY, Putnam County, NY, Queens County, NY, Rockland County, NY, Suffolk County, NY, Sullivan County, NY, Ulster County, NY, Westchester County, NY, Bristol County, RI, Kent County, RI, Newport County, RI, Providence County, RI, Washington County, RI

The radar

The Brookhaven radar (KOKX), 86 km from the middle of the area, began a volume at 19:21 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 12:00Z, 7.3 hours before the alert went out and 86 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: 556 J/kg
Mixed-layer CIN: -80 J/kg
Mixed-layer LCL: 927 m above ground
0-6 km bulk shear: 23 kt
0-1 km storm-relative helicity: 41 m²/s²
0-3 km storm-relative helicity: 77 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 0.5

Open this sounding in Storm Lab

The text

As transmitted.

743 
ACUS11 KWNS 091919
SWOMCD
SPC MCD 091919 
MAZ000-RIZ000-CTZ000-NYZ000-NJZ000-PAZ000-092115-

Mesoscale Discussion 0898
NWS Storm Prediction Center Norman OK
0219 PM CDT Wed Jun 09 2021

Areas affected...Southeastern New York and portions of southern New
England

Concerning...Severe potential...Watch unlikely 

Valid 091919Z - 092115Z

Probability of Watch Issuance...5 percent

SUMMARY...Isolated thunderstorms along a weak surface boundary will
bring potential for damaging downdraft winds this afternoon. Storm
coverage and degree of cold-pool organization is quite unclear. No
WW is expected.

DISCUSSION...Temperatures in southern New England have rise into the
upper 80s F in most locations and may breach 90 F in some locations
later this afternoon. Moderate buoyancy has developed despite only
modest mid-level lapse rates due to a very moist boundary layer
(upper 60s to low 70s F dewpoints). Visible satellite imagery
indicates towering cumulus and isolated thunderstorms developing
from southeastern New York into Massachusetts along/near a slowly
southward moving surface boundary. Additional isolated thunderstorm
development is probable this afternoon as the front nears the
southern New England coast. Storm coverage is likely the biggest
question given the overall weak frontal forcing. Development on
local terrain features or interactions with the sea breeze are the
most probable locations. Subtle enhancement to the northwesterly
flow on the southern flank of an upper cyclone may increase
effective shear to perhaps 20 kts. Isolated damaging winds are
possible with storms this afternoon, particularly where any
clustering of activity can occur. No WW is expected given coverage
uncertainties and storms exiting the coast relatively quickly.

..Wendt/Guyer.. 06/09/2021

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

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

LAT...LON   41487493 42097484 42597416 42597293 42567156 42527056
            42336982 41886973 41327052 40797235 40607320 40537372
            40657421 41117475 41487493

Nearby

Mesoscale Discussions in New York, 2021 Mesoscale Discussions in Massachusetts, 2021 Mesoscale Discussions in Connecticut, 2021 Every mesoscale discussion in 2021

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.