Winter Storm Warning 3, NWS Raleigh, NC

111 
WWUS42 KRAH 250801
WSWRAH

URGENT - WINTER WEATHER MESSAGE
National Weather Service Raleigh NC
401 AM EDT Sun Mar 25 2018

...Wintry precipitation rapidly diminishing across the northern 
Piedmont...

.As an area of low pressure moves away from central 
NC, precipitation coverage and rates will decrease. Thus, no 
additional wintry accumulation is expected across the far 
northern Piedmont of central North Carolina.

NCZ007-021>024-250915-
/O.CAN.KRAH.WS.W.0003.000000T0000Z-180325T1000Z/
Person-Forsyth-Guilford-Alamance-Orange-
Including the cities of Bushy Fork, Concord, Roxboro, Surl, 
Pfafftown, Stanleyville, Winston-Salem, Greensboro, 
Lake Townsend, High Point, Burlington, Graham, Chapel Hill, 
and Carrboro
401 AM EDT Sun Mar 25 2018

...WINTER STORM WARNING IS CANCELLED...

Wintry precipitation was coming to an end across the far northern
Piedmont, thus the Winter Storm Warning has been cancelled.

$$

NCZ008>010-025-026-038>041-250915-
/O.CAN.KRAH.WW.Y.0007.000000T0000Z-180325T1000Z/
Granville-Vance-Warren-Durham-Franklin-Davidson-Randolph-Chatham-
Wake-
Including the cities of Oxford, Butner, Creedmoor, Dabney, 
Henderson, Norlina, Wise, Afton, Warrenton, Lake Gaston, 
Bethesda, Durham, Research Triangle, Pilot, Ingleside, Louisburg,
Franklinton, Lexington, Thomasville, Asheboro, Ulah, Archdale, 
Trinity, Hasty, Siler City, Bynum, Moncure, Pittsboro, Raleigh, 
and Cary
401 AM EDT Sun Mar 25 2018

...WINTER WEATHER ADVISORY IS CANCELLED...

Wintry precipitation was coming to an end across the northern 
Piedmont, thus the Winter Weather Advisory has been cancelled. 

$$

For more information from the National Weather Service, visit
http://weather.gov/raleigh

Area Forecast Discussion
National Weather Service Raleigh NC
815 PM EDT Sat Mar 24 2018

.SYNOPSIS...
An area of low pressure and upper level disturbance will move
northwest to southeast over North Carolina through tonight. Chilly
high pressure will build into the Carolinas from the north Sunday
through Tuesday. This high will move to our southeast and off the
coast Wednesday, bringing a warming trend.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 415 PM Saturday...

Update: Based on new guidance, have expanded the winter weather
advisory area to include northern portions of Alamance, Orange, and
Durham counties for the potential for a half to a much as an inch of
snow, mainly on grassy and elevated surfaces.

The dampening mid level shortwave trough moving into IL will
continue a SE motion, passing through the Carolinas late tonight
into Sun morning. The associated surface low over SE MO will track
SE along the strengthening low level frontal zone, moving toward SW
NC tonight, followed by secondary cyclogenesis just off the SC coast
late. Mostly light precip associated with a weak leading
perturbation has spread across NC, and the initially high dewpoint
depressions have begun to decrease as cloud bases lower. We've
already seen a band of higher precip rates passing over the Triad
produce a period of snow, despite wet bulb temps sitting just above
freezing. That such cooling of the column is already occurring is
concerning, in that it suggests that perhaps a larger area of the
northern Piedmont may see a risk of snow bursts this evening into
the overnight hours. It's expected that as the stronger forcing for
ascent arrives this evening (including low level frontogenetic
forcing, incoming mid level DPVA, and increasing upper divergence
associated with the northwesterly jetlet moving from the W Ohio
Valley through the Carolinas), precip rates will pick up, with any
spotty areas filling in by mid evening. Where the rates are highest,
dynamic cooling is likely to prompt a rain/snow mix to switch over
to mostly snow, not unexpected given projections of a deep near
freezing isothermal layer. Surface temps should in general stay just
above freezing, however a period of surface cooling is apt to occur
within the heaviest precip over the northern Piedmont, causing an
accumulation of snow, primarily on grassy and elevated surfaces. But
if snow comes down heavy enough, some accumulation on roads,
especially bridges/overpasses, is not out of the question. Expect
precip totals of around a half to one inch across central NC, with
far northern Piedmont snowfall of one half to one inch, highest over
northern portions of the advisory area. Once the mid level wave
passes through late tonight, taking the heaviest precip to our east,
temps should rebound a degree or two, such that icy roads won't be a
big concern Sunday morning. Lows will be 31-38, again with the
cooler readings occurring during the heavier precip in the predawn
hours. -GIH

&&

.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
As of 425 PM Saturday...

The by-now-shearing shortwave trough will be exiting to our SE Sun
morning, with the primary surface low dissolving to a weak inverted
trough over the S Appalachians and the secondary surface low moving
further offshore. Copious low level moisture will remain,
particularly over the W and S CWA, although the chilly wedging
surface high may allow for some low level drying over the NE CWA.
Nevertheless, expect a cloudy to mostly cloudy and cool day over
much of the area, and we may see lingering drizzle over the
Piedmont, especially west sections. Highs 43-50. Nocturnal cooling
with the wedge holding firm Sun night will prompt the low clouds to
hold firm, especially over the S and W. Lows 30-37. -GIH

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
As of 200 PM Saturday...

Longer range forecast remains on track with much warmer weather
returning by mid week.

Cold air advection will continue Monday as high pressure ridges down
the Atlantic coast. The cool ridge holds through Tuesday, though
gradually weakening and lifting north into New England. The surface
high lifting out combined with a mid level ridge axis over the area
edging east and offshore Tuesday night will result in deep
SW return flow with strong warm air advection setting up
early Wednesday and continuing into Thursday. Temperatures on
Wednesday will rise into the 60s and then soar into the 70s on
Thursday.

While all of this is going on locally, a long wave trof will be
deepening over the Plains, with strong frontogenesis stretching out
of the Gulf northeastward into the Ohio Valley during the mid week.
The mid level ridge just east of the area will block and slow down
the eastward progression of this surface front, allowing deeper
layer moisture advection into the area, with precipitable waters
edging above 1.5 inches prior to the front's passage early Friday.
A lot of favorable ingredients will be also be present which would
support stronger shower and thunderstorm activity, which would most
likely manifest as a line of strong convection immediately ahead of
the front. Timing will be key, as just a little delay of frontal
passage from Thursday night into Friday would add increased
instability to the mix. Highs Friday will be in the mid 60s north to
mid 70s south.  Ridging builds in Friday night into Saturday with
cooler and dry weather.  Highs Saturday will range from 55 north to
65 south.

&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
As of 815 PM Saturday...

The system producing widespread rain/snow will continue to affect
our region through the night. The main bulk of the precipitation
will be a mix of snow and rain in the NW and rain in the SE.
Widespread IFR to LIFR CIGS and VSBYS can be expected through
09z/Sunday. The precipitation will taper off to light mist and
drizzle between 09z and 12z, with lingering low CIGS/VSBYS through
18z/Sunday.

Looking beyond 18z Sun, within the cool surface ridge wedging down
into central NC, cigs will stay mostly MVFR at INT/GSO, with a trend
to VFR elsewhere Sun afternoon. MVFR conditions should dominate at
INT/GSO through Sun night, with VFR conditions elsewhere. By midday
Mon, VFR conditions are expected areawide, although sub-VFR
conditions may linger at INT/GSO. As the surface high builds
overhead and then drifts SE midweek, VFR conditions should dominate,
although there are signs that the Piedmont terminals may see periods
of sub-VFR clouds Tue into Wed as moisture increases aloft. Cigs
should be VFR Thu with a chance of showers areawide, within
southwest flow ahead of the next approaching storm system. -GIH

&&

.RAH WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from 8 PM this evening to 5 AM EDT Sunday
for NCZ007-008-021>025.

&&

SYNOPSIS...Hartfield
NEAR TERM...Hartfield
SHORT TERM...Hartfield
LONG TERM...mlm/Franklin
AVIATION...Badgett/Hartfield

Hazardous Weather Outlook...UPDATED
National Weather Service Raleigh NC
450 PM EDT Sat Mar 24 2018

NCZ009>011-026>028-038>041-043-250900-
Vance-Warren-Halifax-Franklin-Nash-Edgecombe-Davidson-Randolph-
Chatham-Wake-Wilson-
450 PM EDT Sat Mar 24 2018

This Hazardous Weather Outlook is for central North Carolina.

.DAY ONE...Tonight.

A brief mix of rain and wet snow is possible from late evening
through the overnight hours. No accumulation on roads is expected.

.DAYS TWO THROUGH SEVEN...Sunday through Friday.

Hazardous weather is not expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

NCZ007-008-021>025-250900-
Person-Granville-Forsyth-Guilford-Alamance-Orange-Durham-
450 PM EDT Sat Mar 24 2018

...WINTER WEATHER ADVISORY IN EFFECT FROM 8 PM THIS EVENING TO 5 AM
EDT SUNDAY...

This Hazardous Weather Outlook is for central North Carolina.

.DAY ONE...Tonight.

Please listen to NOAA Weather Radio or go to weather.gov on the
Internet for more information about the following hazards.

   Winter Weather Advisory.

.DAYS TWO THROUGH SEVEN...Sunday through Friday.

Hazardous weather is not expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

NCZ042-073>078-083>086-088-089-250900-
Johnston-Stanly-Montgomery-Moore-Lee-Harnett-Wayne-Anson-Richmond-
Scotland-Hoke-Cumberland-Sampson-
450 PM EDT Sat Mar 24 2018

This Hazardous Weather Outlook is for central North Carolina.

.DAY ONE...Tonight.

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Sunday through Friday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE RALEIGH NC
904 PM EDT Sat Mar 24 2018

NCZ007>009-021>025-250415-
PERSON-GRANVILLE-VANCE-FORSYTH-GUILFORD-ALAMANCE-ORANGE-DURHAM-
INCLUDING THE CITIES OF BUSHY FORK, CONCORD, ROXBORO, SURL,
OXFORD, BUTNER, CREEDMOOR, DABNEY, HENDERSON, PFAFFTOWN,
STANLEYVILLE, WINSTON-SALEM, GREENSBORO, LAKE TOWNSEND,
HIGH POINT, BURLINGTON, GRAHAM, CHAPEL HILL, CARRBORO, BETHESDA,
DURHAM, AND RESEARCH TRIANGLE
904 PM EDT Sat Mar 24 2018

...Light rain changing to wet snow across the northern Piedmont...

A band of higher intensity precipitation will continue to stream
southeastward across the NC northern Piedmont this evening. The
heavier precipitation rates will cause the precipitation to
change to snow, with a several hour period of moderate to briefly
heavy, wet snow likely along the Interstate 85 corridor from the
Triad to near RDU to Henderson. Temperatures will fall to between
32 and 33 degrees during this time, with a slushy snow accumulation
around one to two inches. While the accumulation will be greatest
on elevated and grassy surfaces, a slushy coating can also be
expected on roadways when the precipitation rates are highest.
Snow will then transition to light rain after midnight, before
tapering off between 1 AM and 4 AM.

Motorists are encouraged to exercise caution this evening because
of both slushy and slick roadways, and also visibility reductions
to a less than a quarter to half mile at times during the
heaviest snow.

26

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE RALEIGH NC
925 PM EDT SAT MAR 24 2018

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0924 PM     SNOW             ROXBORO                 36.40N 78.98W
03/24/2018  E0.1 INCH        PERSON             NC   BROADCAST MEDIA

            MODERATE TO HEAVY SNOW, STARTING TO
            ACCUMULATE ON PAVEMENT.

&&

NP