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Raleigh, NC Weather Forecast Office
http://weather.gov/rah
@NWSRaleigh Presentation Created 1/17/2018 10:20 AM
What has Changed: New snowfall
accumulation
map with higher
amounts.
Updated radar
simulations.
Power outage
possibility given
higher snow
amounts.
Winter storm conditions with extremely hazardous travel is underway now across much of central North Carolina.
As of 10:15 AM January 17th, 2018
the repla e What has Cha ged with I itial Briefi g , followed with a
i the ase, it is the Mostly Likely S owfall graphi .
Raleigh, NC Weather Forecast Office
http://weather.gov/rah
@NWSRaleigh Presentation Created 1/17/2018 10:20 AM
Main Points
Hazard Impacts Location Timing
Snow 3 to 6 inches of snow All of Central NC,
especially the Piedmont Counties.
This morning through this evening
Wind Chill Wind chills will approach single
digits All of Central NC
Tonight into Thursday morning
Hazardous
Travel
Roads will be treacherous,
especially overpasses and secondary roads
All of Central NC,
especially the Northeast Piedmont and Northern
Coastal Plain.
Today through Thursday morning
Power
Outages Scattered power outages are
expected
All of Central NC, especially the Piedmont
Counties.
Today through Thursday morning
Raleigh, NC Weather Forecast Office
http://weather.gov/rah
@NWSRaleigh Presentation Created 1/17/2018 10:20 AM
Travel Hazards: All of Central NC
Plain
Wind Chills: this Night - All of Central NC
Snow: All of Central NC
None Limited Elevated Significant Extreme
Summary of Greatest Impacts
None Limited Elevated Significant Extreme
None Limited Elevated Significant Extreme
Power Outages: All of Central NC
None Limited Elevated Significant Extreme
Raleigh, NC Weather Forecast Office
http://weather.gov/rah
@NWSRaleigh Presentation Created 1/17/2018 10:20 AM
Updated Forecast Snow Accumulations
Raleigh, NC Weather Forecast Office
http://weather.gov/rah
@NWSRaleigh Presentation Created 1/17/2018 10:20 AM
Radar Simulations for Timing Estimates
Precipitation will gradually spread east today. The eastward and southern leading edge of the
precipitation will start as rain, but will gradually mix with and change to snow as the
precipitation continues. By late morning, precipitation will be all snow west of the US-1
corridor, and that transition will shift toward the I-95 corridor by Noon. Once the precipitation
changes to snow, it will begin accumulating very quickly due to heavy precip rates.
Moderate to heavy
snow in this band
with rapid
accumulations
occurring
Here is what the actual radar looked like at 10:15
AM. Temperatures and precip type also shown.
This is a simulation of what the radar may like
around Noon today. Precip type also shown.
Raleigh, NC Weather Forecast Office
http://weather.gov/rah
@NWSRaleigh Presentation Created 1/17/2018 10:20 AM
Radar Simulations for Timing Estimates
This is a simulation of what the radar may
like between 1 and 3 PM today
This is a simulation of what the radar may
like between 3 and 5 PM today
This is a simulation of what the radar may
like between 5 and 7 PM today
This is a simulation of what the radar may
like between 9 and 11 PM today
Heavy
Snow
Heavy
Snow
Heavy
Snow
Moderate
Snow
Moderate
Snow
Rain
Heavy
Snow
Rain Changing to
Snow
Moderate
Snow
Light
Snow
Light
Snow
Winding
Down
Light
Snow
Light
Snow
Moderate
Snow
Moderate
Snow
Light
Snow
Winding
Down
Dry
Raleigh, NC Weather Forecast Office
http://weather.gov/rah
@NWSRaleigh Presentation Created 1/17/2018 10:20 AM
Impacts: Any snow or slush will
freeze on roads, bridges
and overpasses.
Frost bite and
hypothermia can occur if
precautions are not taken.
Wind chill values could
be lower where snow
accumulates.
Expected Wind Chills for this Night/Thursday
Morning
Website: www.weather.gov/raleigh Twitter: @NWSRaleigh
Facebook: https://www.facebook.com/US.NationalWeatherService.Raleigh.gov
Daily Morning Episodes of Black Ice Possible After the Snowfall
Black ice is expected on roads
and walkways Thursday
morning. Black ice will be
possible Friday morning as well
in areas where there is
lingering snow.
During those times, please be
extra cautious when venturing
out. Roads that appear clear or
merely wet may actually be
coated with a thin layer of ice.
Winter Weather Advisories for
black ice will likely be issued in
the wake of the storm.
Example of what black ice may look like.
Raleigh, NC Weather Forecast Office
http://weather.gov/rah
@NWSRaleigh Presentation Created 1/17/2018 10:20 AM
Additional Key Points
Models have trend up with snowfall amounts the last several runs.
Once the change-over from rain to snow occurs, the temperature will quickly fall and
snowfall accumulation may begin fairly quickly. Elsewhere, occasional bursts of heavier
snow may occur, resulting in road conditions quickly deteriorating. That is, road
conditions could go from being fine one minute, to treacherous the next minute, when
and where these heavy snow bursts occur.
Hourly snowfall rates of greater than 1 inch per hour will be possible in the heavier
snow bands.
While 3-6 inches of snow will be possible across a large portion of central NC, a narrow,
very localized band of heavier snow will be possible, resulting in a localized higher
a u ulatio a ou t. It’s just too diffi ult at this poi t to ide tify whi h parti ular areas may see this localized intense snow band and greater snowfall amounts.
Possi le alter ate s e arios… Best case: eastern leading edge of precip shield remains rain longer than expected and cuts down on snow
amounts.
Worst case: Upper disturbance intensifies or slows down, and several bands of heavy/intense snow form
resulting in higher amounts.
Raleigh, NC Weather Forecast Office
http://weather.gov/rah
@NWSRaleigh Presentation Created 1/17/2018 10:20 AM
Event Summary
What’s the take away
Snow accumulations of 3-6 inches possible late tonight through this
All of central NC is expected to see accumulating snowfall, with temps
falling into the 20s on this, and teens by Thursday morning.
Winter Storm Warnings and Winter Weather Advisories are in effect
through this evening for all of central NC.
Period of greatest impact: This morning through this evening. Very difficult
and dangerous travel conditions expected due to snow-covered and slick
roads.
Very cold temperatures in the teens and wind chills in the single digits are
expected this night and Thursday morning.
Black ice will be possible on roads and walkways Thursday and Friday
(mornings especially) across the parts of central North Carolina that receive
snow accumulation. Winter Weather Advisories for black ice will likely be
needed in the wake of the storm.
Raleigh, NC Weather Forecast Office
http://weather.gov/rah
@NWSRaleigh Presentation Created 1/17/2018 10:20 AM
Contact and Next Briefing Information
Briefing Webpage: http://www.weather.gov/media/rah/briefing/NWSRaleighLatestBriefing.pdf
Next Briefing When: By 500 PM on 1/17/2018
Method: E-mail
Web:
http://weather.gov/rah
Phone (public):
(919) 326-1052
E-mail:
Facebook:
NWSRaleigh
Twitter:
@NWSRaleigh
YouTube:
NWSRaleigh
Disclaimer: The information contained within this briefing
is time-sensitive. Do not use after 2:00 PM, Tuesday, January 17th, 2018
