Alert archive / Maine / Mesoscale Discussions in 2012

Mesoscale Discussion 581

April 23, 20124 counties in Maine

The Storm Prediction Center issued this mesoscale discussion at Apr 23, 2012, 3:37 AM EDT for 4 counties in Maine. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued: Apr 23, 2012, 3:37 AM EDT (07:37 UTC)
Expired: Apr 23, 2012, 7:30 AM EDT
In force: 4 hr
Issued by: the Storm Prediction Center

Counties Aroostook County, ME, Franklin County, ME, Piscataquis County, ME, Somerset County, ME

The radar

The Caribou radar (KCBW), 125 km from the middle of the area, began a volume at 07:39 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 00:00Z, 7.6 hours before the alert went out and 140 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: 2 J/kg
Mixed-layer CIN: 0 J/kg
Mixed-layer LCL: 556 m above ground
0-6 km bulk shear: 63 kt
0-1 km storm-relative helicity: 87 m²/s²
0-3 km storm-relative helicity: 211 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.

139 
ACUS11 KWNS 230738
SWOMCD
SPC MCD 230737
MEZ000-231130-

MESOSCALE DISCUSSION 0581
NWS STORM PREDICTION CENTER NORMAN OK
0237 AM CDT MON APR 23 2012

AREAS AFFECTED...NRN ME

CONCERNING...FREEZING RAIN

VALID 230737Z - 231130Z

A CHANGEOVER FROM LIGHT SNOW TO FREEZING RAIN IS EXPECTED TO OCCUR
BETWEEN 08-10Z.  PRECIPITATION RATES WILL APPROACH 0.10-0.15 INCH/HR
THROUGH 12-15Z BEFORE A TRANSITION TO RAIN OCCURS.

07Z SURFACE ANALYSIS SHOWS PRIMARY CYCLONE OVER NJ WITH AN
ASSOCIATED WARM FRONT EXTENDING ENEWD ACROSS LONG ISLAND SOUND...ERN
CT AND E-CNTRL MA.  A CORRIDOR OF ENHANCED PRESSURE FALLS WAS
OBSERVED N OF THE WARM FRONT FROM THE HUDSON VALLEY EWD INTO SWRN
ME...LIKELY DENOTING STRONG LOW TO MID-TROPOSPHERIC WAA ASSOCIATED
WITH EXIT REGION OF 50+ KT LLJ /PER BOX VWP/.

LATEST MODEL GUIDANCE REMAINS CONSISTENT IN SUGGESTING THAT THE
SURFACE LOW WILL CONTINUE TO DEVELOP NNWWD INTO THE LOWER HUDSON
VALLEY THROUGH 12Z WHILE ASSOCIATED WARM CONVEYOR BELT /AND 50-70 KT
SSELY LLJ/ DEVELOPS NWD THROUGH NEW ENGLAND.  RECENT SURFACE
OBSERVATIONS AT MILLINOCKET...HOULTON...AND CARIBOU INDICATE EITHER
SNOW OR LIGHT RAIN WITH BOUNDARY LAYER CONDITIONS CHARACTERIZED BY
TEMPERATURES OF 33-34 F AND DEWPOINTS OF 30-32 F.

EXPECT A CHANGEOVER TO FREEZING RAIN BETWEEN 08-10Z WITH AN INCREASE
IN PRECIPITATION RATES AS THE ENHANCED ZONE OF WAA MENTIONED ABOVE
DEVELOPS NWD ACROSS THE DISCUSSION AREA.  FREEZING RAIN WILL
CONTINUE THROUGH SUNRISE WITH HOURLY RATES APPROACHING 0.10-0.15
INCH...BEFORE A TRANSITION TO RAIN OCCURS BY LATE MORNING.

..MEAD.. 04/23/2012

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

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

LAT...LON   45217097 45907028 46747000 47346928 47396817 47016760
            46366768 45836816 45046973 44767079 45217097

Nearby

Mesoscale Discussions in Maine, 2012 Every mesoscale discussion in 2012

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.