Mesoscale Discussion 16

Issued

Jan 12, 2012, 3:52 AM EST (08:52 UTC)

Expired

Jan 12, 2012, 9:45 AM EST

In force

6 hr

Issued by

the Storm Prediction Center

The Burlington radar (KCXX), 116 km from the middle of the area, began a volume at 08:50 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.

469 
ACUS11 KWNS 120853
SWOMCD
SPC MCD 120852
NHZ000-MAZ000-VTZ000-NYZ000-121445-

MESOSCALE DISCUSSION 0016
NWS STORM PREDICTION CENTER NORMAN OK
0252 AM CST THU JAN 12 2012

AREAS AFFECTED...PORTIONS E-CENTRAL/NERN NY...WRN THROUGH SRN
VT...SWRN NH...NRN/WRN MA.

CONCERNING...WINTER MIXED PRECIPITATION

VALID 120852Z - 121445Z

COMPLEX/MIXED-PHASE WINTER PRECIP EVENT WILL OCCUR THROUGH MID-LATE
MORNING LOCAL TIME OVER DISCUSSION AREA.

CORRIDOR NEAR AND JUST N OF I-90 IN NY FROM RME ESEWD OVER NRN MA
SHOULD ALTERNATE BETWEEN RAIN AND SNOW WITH SFC TEMPS REMAINING AT
OR JUST ABOVE FREEZING.  SNOW AND FREEZING RAIN ARE MOST PROBABLE
PRECIP TYPES N OF CURRENT FREEZING LINE BEFORE SRN PORTIONS CHANGE
TO RAIN.  SUSTAINED SNOW IS MORE PROBABLE WITH NWD EXTENT THROUGH
ADIRONDACKS AND VT WHERE LOW-MIDDLE LEVEL TEMPS WILL REMAIN COLDEST
FOR LONGEST TIME.  POCKETS OF FREEZING RAIN WILL OFFER RATES NEAR
.10 INCH/HOUR...INTERSPERSED WITH SNOW RATES GENERALLY NEAR 1
INCH/HOUR...LOCALIZED ENHANCEMENTS POSSIBLE.  SPORADIC/BRIEF SLEET
ALSO CANNOT BE RULED OUT.

EXTENSIVE PRECIP PLUME IS EVIDENT IN REFLECTIVITY/IR IMAGERY MOVING
NNEWD INTO THIS REGION...RELATED TO CONVEYOR OF LOW-LEVEL WAA ABOVE
RELATIVELY STABLE/COLD BOUNDARY LAYER.  PRECIP FALLING INTO
RELATIVELY DRY AIR WILL BOOST WET-BULB TEMPS TO NEAR 32 F OVER SRN
ADIRONDACKS/SRN VT/WRN MA REGION...BENEATH VARIABLY DEEP/WARM LAYER
OF SUPERFREEZING TEMPS CENTERED GENERALLY BETWEEN 800-850 MB LEVELS.
THAT VARIABILITY...ALONG WITH CHANGES IN ELEVATION ACROSS THIS
AREA...WILL LEAD TO LOCALIZED CHANGES IN PRECIP PHASE BOTH ACROSS
SMALL DISTANCES AND WITH TIME.

IR ANIMATIONS AND PROJECTED TRACK OF PARENT SYSTEM INDICATE BACK
EDGE OF WAA PLUME SHOULD MOVE ACROSS I-90 CORRIDOR E OF RME AROUND
10Z.  THIS WILL BE FOLLOWED BY NARROW MID-UPPER DRY SLOT...ALTHOUGH
PRECIP STILL MAY BE FALLING IN LOW LEVELS.  COLD-CORE REGION OF
MIDLEVEL TROUGH WILL FOLLOW AFTER ABOUT 14Z.  FCST SOUNDINGS THEN
REASONABLY INDICATE COLUMNAR COOLING OVER ADIRONDACKS AND UVV WITHIN
DENDRITIC GROWTH LAYER.  THIS...IN TURN...SHOULD LEAD TO LIKELY
CHANGEOVER OF ANY REMAINING LIQUID/MIXED TO ALL SNOW...ALTHOUGH SOME
OF THAT SNOW MAY MELT AGAIN BEFORE REACHING GROUND IN PORTIONS SRN
ADIRONDACKS/HUDSON VALLEY REGION WHERE LOW-LEVEL WAA SUFFICIENTLY
HAS WARMED NEAR-SFC TEMPS.

..EDWARDS.. 01/12/2012

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

ATTN...WFO...GYX...BOX...BTV...ALY...BGM...BUF...

LAT...LON   42467279 42477344 43087489 43887567 44197597 44517574
            44907510 45007480 44977421 44347294 42887171 42607221
            42467279

Mesoscale Discussions in New York, 2012Mesoscale Discussions in Vermont, 2012Mesoscale Discussions in New Hampshire, 2012Every mesoscale discussion in 2012

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.