Alert archive / New Hampshire / Mesoscale Discussions in 2018
Mesoscale Discussion 1713
The Storm Prediction Center issued this mesoscale discussion at Dec 16, 2018, 9:36 PM EST for 5 states. It was in force for 4 hr.
The area
The outline as issued.
The facts
- Issued
- Dec 16, 2018, 9:36 PM EST (02:36 UTC)
- Expired
- Dec 17, 2018, 1:30 AM EST
- In force
- 4 hr
- Issued by
- the Storm Prediction Center
All 21 counties
Berkshire County, MA, Franklin County, MA, Cumberland County, ME, York County, ME, Belknap County, NH, Carroll County, NH, Cheshire County, NH, Hillsborough County, NH, Merrimack County, NH, Rockingham County, NH, Strafford County, NH, Sullivan County, NH, Albany County, NY, Columbia County, NY, Rensselaer County, NY, Saratoga County, NY, Schenectady County, NY, Washington County, NY, Bennington County, VT, Windham County, VT, Windsor County, VT
The radar
The Boston radar (KBOX), 153 km from the middle of the area, began a volume at 02:39 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
Albany, NY (KALY), launched 00:00Z, 2.6 hours before the alert went out and 137 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.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 612 m above ground
- 0-6 km bulk shear
- 29 kt
- 0-1 km storm-relative helicity
- 117 m²/s²
- 0-3 km storm-relative helicity
- 233 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
854
ACUS11 KWNS 170237
SWOMCD
SPC MCD 170236
MEZ000-NHZ000-MAZ000-VTZ000-CTZ000-NYZ000-170630-
Mesoscale Discussion 1713
NWS Storm Prediction Center Norman OK
0836 PM CST Sun Dec 16 2018
Areas affected...Portions of New England and eastern New York
Concerning...Winter mixed precipitation
Valid 170236Z - 170630Z
SUMMARY...Winter mixed precipitation is expected to continue/develop
across portions of New England and eastern New York overnight.
Freezing rain, sleet, and snow are all possible across the area.
DISCUSSION...A surface cyclone is centered south-southeast of Long
Island with an associated upper-level trough located almost directly
overhead. Forcing for ascent is spreading over much of New England
and portions of New York where precipitation has continued for
multiple hours. Surface temperatures are hovering near/above
freezing across much of the interior of New England and New York.
Radar imagery shows bright banding/melting layer at 3000-4500 ft.
AGL across central New England. However, the melting layer is
lowering with indications the warm nose is eroding aloft as cold air
advection and precipitation cools this layer. Additionally, KENX is
displaying characteristics of the melting layer lowering with
sleet/snow becoming more likely at the surface and across the higher
terrain with freezing rain also possible within the transition zone.
Trends toward winter mixed precipitation developing/expanding across
portions of New England are favorable overnight as the upper-level
trough/surface low track east-northeast.
..Nauslar/Mosier.. 12/17/2018
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...GYX...BOX...BTV...ALY...
LAT...LON 42037321 42107352 42357402 42747418 43037412 43317378
43457349 43597308 43747239 43867167 44057095 44087055
43987025 43747023 43547035 43307054 43187076 43017102
42787157 42667220 42567249 42427285 42227304 42037321SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Dec 16, 9:24 PM EST | Mesoscale Discussion | SPC | Cumberland, York | 4 hr |
| Dec 17, 2:03 AM EST | Mesoscale Discussion | SPC | Androscoggin, Cumberland, Hancock, Kennebec, Knox, Lincoln and 5 more | 6 hr |
Nearby
Mesoscale Discussions in New Hampshire, 2018Mesoscale Discussions in New York, 2018Mesoscale Discussions in Vermont, 2018Every mesoscale discussion in 2018
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.