Alert archive / Maine / Mesoscale Discussions in 2021

Mesoscale Discussion 1523

August 14, 202114 counties in Maine

The Storm Prediction Center issued this mesoscale discussion at Aug 14, 2021, 12:24 PM EDT for 14 counties in Maine. It was in force for 96 min.

The area

The outline as issued.

The facts

Issued: Aug 14, 2021, 12:24 PM EDT (16:24 UTC)
Expired: Aug 14, 2021, 2:00 PM EDT
In force: 96 min
Issued by: the Storm Prediction Center
Concerning: Severe potential...watch unlikely
Chance of a watch: 20%

Counties Androscoggin County, ME, Aroostook County, ME, Cumberland County, ME, Hancock County, ME, Kennebec County, ME, Knox County, ME, Lincoln County, ME, Penobscot County, ME, Piscataquis County, ME, Sagadahoc County, ME, Somerset County, ME, Waldo County, ME, Washington County, ME, York County, ME

The radar

The Caribou radar (KCBW), 111 km from the middle of the area, began a volume at 16:22 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, 4.4 hours before the alert went out and 173 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: 451 J/kg
Mixed-layer CIN: -123 J/kg
Mixed-layer LCL: 1044 m above ground
0-6 km bulk shear: 32 kt
0-1 km storm-relative helicity: 28 m²/s²
0-3 km storm-relative helicity: 142 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

826 
ACUS11 KWNS 141624
SWOMCD
SPC MCD 141624 
MEZ000-NHZ000-141800-

Mesoscale Discussion 1523
NWS Storm Prediction Center Norman OK
1124 AM CDT Sat Aug 14 2021

Areas affected...central and eastern ME

Concerning...Severe potential...Watch unlikely 

Valid 141624Z - 141800Z

Probability of Watch Issuance...20 percent

SUMMARY...Isolated strong thunderstorms could produce strong,
locally damaging wind gusts this afternoon.

DISCUSSION...Thunderstorms are increasing in coverage and intensity
in the vicinity of a surface cold front across western ME. Morning
convection that moved across the state has limited heating over
portions of the region, but some airmass recovery is underway.
Dewpoints in the upper 60s to near 70 F beneath moderate midlevel
flow will support isolated strong convection through the afternoon
as the cold front progresses east/southeast across New England.
Pockets of 1000-1500 J/kg MLCAPE and steepening low level lapse
rates, along with PW values approaching 2 inches, will support
semi-organized cells/clusters capable of sporadic strong, to locally
damaging gusts. Marginal effective shear magnitudes and a lack of
stronger instability with poor midlevel lapse rates should limit a
more organized and intense threat, and a watch is not expected at
this time.

..Leitman/Hart.. 08/14/2021

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

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

LAT...LON   47166889 47366826 47236802 46966768 46046751 45426738
            44836738 44456772 43536955 43197064 43577100 43967088
            44617054 45816985 46226956 47166889

Nearby

Mesoscale Discussions in Maine, 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.