Alert archive / Maine / Mesoscale Discussions in 2021

Mesoscale Discussion 1014

June 19, 20218 counties in Maine

The Storm Prediction Center issued this mesoscale discussion at Jun 19, 2021, 3:44 PM EDT for 8 counties in Maine. It was in force for 91 min.

The area

The outline as issued.

The facts

Issued
Jun 19, 2021, 3:44 PM EDT (19:44 UTC)
Expired
Jun 19, 2021, 5:15 PM EDT
In force
91 min
Issued by
the Storm Prediction Center
Concerning
Severe potential...watch unlikely
Chance of a watch
20%

Counties Hancock County, ME, Kennebec County, ME, Knox County, ME, Lincoln County, ME, Penobscot County, ME, Sagadahoc County, ME, Waldo County, ME, Washington County, ME

The radar

The Caribou radar (KCBW), 98 km from the middle of the area, began a volume at 19:46 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

Caribou, ME (KCAR), launched 12:00Z, 7.7 hours before the alert went out and 184 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, Caribou, ME at 12:00Z on 2021-06-19Temperature 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°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Caribou, ME at 12:00Z on 2021-06-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 181 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
549 m above ground
0-6 km bulk shear
37 kt
0-1 km storm-relative helicity
181 m²/s²
0-3 km storm-relative helicity
178 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

824 
ACUS11 KWNS 191944
SWOMCD
SPC MCD 191944 
MEZ000-192115-

Mesoscale Discussion 1014
NWS Storm Prediction Center Norman OK
0244 PM CDT Sat Jun 19 2021

Areas affected...Eastern Maine

Concerning...Severe potential...Watch unlikely 

Valid 191944Z - 192115Z

Probability of Watch Issuance...20 percent

SUMMARY...Isolated large hail and damaging winds are possible
through the early evening.

DISCUSSION...A line of storms which had previously struggled to
organize has strengthened in the last 15 to 30 minutes. This is
likely the result of these storms reaching better low-level
moisture/convergence where low-level flow is more backed and
advecting off the ocean. The KGYX VWP shows 50 knots of flow around
5 km which is sufficient for storm organization. This line of storms
is a combination of both bowing segments and embedded supercells.
The thermodynamic environment is not overly favorable with MLCAPE
around 500 J/kg, but isolated large hail, damaging wind, or even a
tornado remains possible. A watch is unlikely due to the limited
instability as well as the relatively short duration of the threat
before storms move offshore.

..Bentley/Hart.. 06/19/2021

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

ATTN...WFO...CAR...GYX...

LAT...LON   43987025 45286943 46656827 47126793 47176732 46316757
            45676729 45176692 44776690 44476717 43786858 43576993
            43987025

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jun 19, 12:38 PM EDTMesoscale DiscussionSPCAndroscoggin, Aroostook, Franklin, Oxford, Piscataquis, Somerset97 min

Nearby

Mesoscale Discussions in Maine, 2021Every 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.