SPC MD 1633


MD 1633 Image

Mesoscale Discussion 1633
NWS Storm Prediction Center Norman OK
0846 PM CST Fri Nov 09 2018

Areas affected...Northern Vermont...Northern New
Hampshire...Portions of western/northern Maine

Concerning...Heavy snow 

Valid 100246Z - 100845Z

SUMMARY...Heavy snowfall rates of 1+ inches/hour likely across
northern Vermont into western/northern Maine, with rain
transitioning to a snow/wintry mix farther south. The period of
heaviest snow is expected to be concentrated within the 0300-0900
UTC time frame.

DISCUSSION...As differential cyclonic vorticity advection increases
with the approach of a longwave trough, ascent is expected to
further increase, particularly within a deepening and saturated
dendritic growth layer. Strong 850-700 mb WAA/frontogenesis is
already underway across central New England, and coupled with
sub-freezing vertical profiles and ample moisture within a deep
layer of the troposphere, accumulating snowfall has already occurred
(especially in higher elevations) as noted by recent reports across
central Vermont. While surface temperatures are above freezing
across most areas in the lower elevations (with a change over from
rain to a wintry mix evident by KENX dual-polarimetric radar),
further cooling is expected to take place at the surface, through a
deep-layer of a saturated troposphere, prompting a change over to
all snow across much of central/northern New England. 

Latest deterministic and ensemble high resolution guidance supports
1+ inch/hour snowfall rates across far northern Vermont, northern
New Hampshire, and western/northern Maine, mainly within the
0300-0900 UTC time frame. The heavier snowfall accumulations will
occur in far northeast New York, into northern Vermont and New
Hampshire in the near term, with the higher snowfall rates
translating to portions of Maine later in the period, coincident
with stronger deep layer ascent and 700 mb WAA.

..Squitieri.. 11/10/2018

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


LAT...LON   44767313 44987279 44977176 45157135 45167085 45587046
            46177013 46906975 47286915 47076872 45146955 43807131
            43977321 44267360 44697326 44767313 

Read more

Source link

  • Editor