Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC
FXUS62 KRAH 240555
Area Forecast Discussion
National Weather Service Raleigh NC
1255 AM EST Tue Jan 24 2017
A deep low pressure system will lift northeast up the northern Mid
Atlantic coast today, reaching the New England coast tonight. High
pressure will then influence the region through midweek.
.NEAR TERM /THROUGH TONIGHT/...
As of 1030 PM Monday...
Multiple layer of moisture and cloudiness were lingering over our
region due to the slow movement of the mid/upper low on the coast.
Western and central NC were now on the subsidence side of the system
and with the continued downslope flow as well behind the departing
low, cloudiness will begin to erode from the lee of the mountains
later tonight. In addition, a band of light showers will continue to
affect the Yadkin Valley for a few hours, otherwise the rain is
finished with this storm for our region.
The cold front has already pushed south of the region and the CAA has
begun. Winds have become northerly and this will drive the cool air
in. The temperatures will fall into the 35-40 range north and 40-45
south overnight. Some gustiness with the CAA initially may reach 20
mph, but overall the trend will be for winds to decrease to 10 mph
or less overnight.
.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
As of 250 PM Monday...
Ridging aloft will develop behind the departing low on Tuesday,
with cold advection easing up through the day. Skies will have
generally cleared, but forecast soundings suggest some
scattered cu during the afternoon and wind gusts to near 20kt.
prefer a blend of MOS for highs, 59-62 and coolest northeast
where cold advection lasts longest.
Relatively mild high pressure will nose in from the south
Tuesday night before quickly retreating ahead of the next cold
front. Lows 38-42
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
As of 210 PM Monday...
A transition from mild conditions to more seasonable, but generally
dry ones, will occur during the medium range.
Ridging aloft will crest over the Ern U.S. on Wed, then move
offshore in advance of a broad, positive tilt longwave trough that
will migrate Ewd and encompass the Ern two thirds of Ern North
America by the weekend.
A surface cold front --one related to the lead shortwave trough that
will initiate the Ewd progression of the longwave trough, and which
will trail a parent surface cyclone that will migrate NEwd across
the Great Lakes-- will settle across NC late Wed night-Thu. Both
moisture and lift are forecast to be limited, as the parent forcing
lifts to our NW, so rainfall chances and amounts are likewise
expected to be limited.
Behind this lead front, temperatures will cool to more seasonable/
average levels for the end of the week and weekend. The positive
tilt configuration of the trough aloft will cause surface high
pressure to sprawl into the SErn U.S. and suppress any additional
precipitation chances until Sun-Mon, at which time a Nrn stream
shortwave trough in NW flow aloft will amplify into the Middle
Atlantic region and possibly support some degree of cyclogenesis
over the Wrn Atlantic. At this time, it appears that a generally dry
reinforcing cold frontal passage will result for our region, though
the prospects of nearby coastal cyclogenesis will be worth
watching in the coming days.
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
As of 1255 AM Tuesday...
24-Hour TAF period: Deep low pressure will move northeast, away from
Central NC through the day on Tuesday. Very light rain on the
back side of the departing low will overspread the Triad the next
couple of hours, but precip is so light, NSW is expected. In the
wake of the low pressure system, drier air will filter into the area
from west. MVFR ceilings have already scattered out at KINT and
KGSO. And we will see this trend continue from west to east
between 06 to 12z.
Breezy NWLY winds will develop everywhere by mid to late
morning with sustained winds of 14 to 17kts, gusting to
25 to 30kt through the afternoon. Winds should decouple
by the evening as surface ridge axis extends into the
area from the south.
Looking ahead: VFR conditions are expected through Wednesday. A cold
front will cross the region late Wednesday night/early Thursday,
bringing with a chance of showers and sub-VFR ceilings to the area.
VFR conditions should return late Thursday afternoon/evening.