Alert archive / Maine / Mesoscale Discussions in 2014

Mesoscale Discussion 708

May 26, 2014Penobscot County, Piscataquis County, Somerset County, Maine

The Storm Prediction Center issued this mesoscale discussion at May 26, 2014, 12:05 PM EDT for Penobscot County, Piscataquis County, Somerset County, Maine. It was in force for 115 min.

The area

The outline as issued.

The facts

Issued: May 26, 2014, 12:05 PM EDT (16:05 UTC)
Expired: May 26, 2014, 2:00 PM EDT
In force: 115 min
Issued by: the Storm Prediction Center
Chance of a watch: 20%

Counties Penobscot County, ME, Piscataquis County, ME, Somerset County, ME

The radar

The Caribou radar (KCBW), 94 km from the middle of the area, began a volume at 16:09 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

Severe Thunderstorm Watch 187May 26, 2:15 PM EDT

The nearest sounding before it

Caribou, ME (KCAR), launched 12:00Z, 4.1 hours before the alert went out and 145 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 460 m above ground
0-6 km bulk shear: 44 kt
0-1 km storm-relative helicity: 330 m²/s²
0-3 km storm-relative helicity: 354 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

407 
ACUS11 KWNS 261605
SWOMCD
SPC MCD 261605 
MEZ000-261800-

MESOSCALE DISCUSSION 0708
NWS STORM PREDICTION CENTER NORMAN OK
1105 AM CDT MON MAY 26 2014

AREAS AFFECTED...PARTS OF ME

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 261605Z - 261800Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...AN ISOLATED THREAT FOR HAIL AND/OR STRONG WIND GUSTS WILL
BE POSSIBLE THROUGH THE AFTERNOON ACROSS ME AS A BACKDOOR COLD FRONT
ADVANCES SWD ACROSS THIS REGION.  COVERAGE OF STRONGER STORMS SHOULD
BE LOW SUCH THAT WW ISSUANCE IS UNLIKELY AT THIS TIME. 
HOWEVER...CONVECTIVE TRENDS WILL BE MONITORED FOR ANY CHANGE IN
COVERAGE POTENTIAL AND THE NEED FOR A WW.

DISCUSSION...A BACKDOOR SURFACE FRONT...CURRENTLY HAVING MOVED SWD
INTO FAR NRN ME AND EXTENDING WNWWD INTO SRN QUEBEC...SHOULD HAVE
THE GREATEST SWD MOVEMENT ACROSS ME THROUGH THE AFTERNOON AS THIS
REGION WILL BE LOCATED BENEATH STRENGTHENING NWLY FLOW ALOFT.  THE
ENVIRONMENT SOUTH OF THE FRONT AS BEEN GRADUALLY DESTABILIZING
THROUGH THE MORNING WITH MUCAPE STILL LESS THAN 500 J/KG.  THERE HAS
BEEN SOME INCREASE IN LOW LEVEL MOISTURE PER WNWLY WINDS ADVECTING
SURFACE DEWPOINTS IN THE MID 50S FROM SRN QUEBEC INTO ME AHEAD OF
THE FRONT.  HOWEVER...GENERALLY WEAKER MIDLEVEL LAPSE RATES ACROSS
MUCH OF THIS REGION...ASIDE FROM FAR NRN-ERN ME WHERE 700-500 MB
LAPSE RATES ARE AROUND 7 C/KM PER 12Z CAR SOUNDING...SHOULD LIMIT
STRONGER DESTABILIZATION.  SURFACE HEATING SHOULD STEEPEN LOW-LEVEL
LAPSE RATES SOME...AND STRENGTHENING NWLY WINDS /50-70 KT AT 500 MB/
AS A MIDLEVEL CLOSED LOW SHIFTS E TO THE N OF ME WILL ENHANCE BULK
SHEAR FOR SOME STORM ORGANIZATION.  THUS...A FEW STORMS WILL BE
CAPABLE OF PRODUCING HAIL APPROACHING 1 INCH IN DIAMETER AND
STRONGER WIND GUSTS WHERE SURFACE HEATING IS MAXIMIZED.

..PETERS/CORFIDI.. 05/26/2014

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

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

LAT...LON   46487007 46446902 46836794 46726773 45856760 45496745
            44906796 44736878 44816970 44997038 45257068 46487007

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 26, 1:56 PM EDT	Mesoscale Discussion	SPC	Aroostook, Franklin, Penobscot, Piscataquis, Somerset, Washington	34 min
May 26, 2:14 PM EDT	Severe Thunderstorm Watch	SPC	Androscoggin, Aroostook, Cumberland, Franklin, Hancock, Kennebec and 9 more	6 hr

Nearby

Mesoscale Discussions in Maine, 2014 Every mesoscale discussion in 2014

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.