Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
FXUS62 KRAH 191929
Area Forecast Discussion
National Weather Service Raleigh NC
230 PM EST Thu Jan 19 2017
An upper level trough over the Tennessee Valley this afternoon will
pivot northeast over western North Carolina into Virginia tonight
and Friday. This will be followed by a brief quiet period Friday
afternoon and night. Then... a strong storm system is expected to
affect the region over the weekend into Monday.
.NEAR TERM /THIS AFTERNOON THROUGH TONIGHT/...
As of 1132 AM Thursday...
The cooler and drier air mass was in place over the region courtesy
of the surface high pressure. The latest data indicated mostly sunny
to sunny skies. Satellite and surface observations support sunny
skies becoming partly sunny in the west later today. Highs are still
expected to reach the upper 50s to lower 60s with light and variable
Cloud cover will begin continue to increase from the southwest this
evening as a southern stream system approaches. Rain chances will
increase for the SW Piedmont after 06z, and spread northeast
overnight. QPF of around 0.25 NW to less than 0.10 expected SE.
Lows in the mid 40s to near 50.
.SHORT TERM /FRIDAY AND FRIDAY NIGHT/...
As of 335 AM Thursday...
Rain will continue across central NC on Friday as a disorganized
frontal system moves across the area. Rain will continue into the
late afternoon or early evening ending from west to east as it does
so. Total accumulations of rainfall are expected to be somewhere in
the neighborhood of a tenth to a quarter of an inch. Temperatures
will be dictated by cloud cover but warm air advection ahead of the
system will bring max temps up into the mid 60s across the south,
with upper 50s to low 60s across the north. Lows Friday night in the
upper 40s to low 50s.
.LONG TERM /Saturday through Thursday/...
-- Changed Discussion --As of 230 PM Thursday...
A wet, but mild spell is on tap for the weekend into early next week
as a strong cutoff low pressure area digs into the midwest and
across the Gulf states before lifting up the Atlantic coast on
Tuesday. Timing confidence is fairly high, while finer details of
potentially how much rain where are still somwhate murky. There
appear to be at least 3 distinct periods of potential showers as
this slow-moving system taps into the Gulf and feeds abundant
moisture north up the Atlantic coast. An initial short wave and
associated surface warm front will be lifting northeast, steered by
an upper ridge over the eastern seaboard on Saturday, with showers
spreading north into the area by afternoon and lingering through
Saturday night. Shower coverage may be a bit diminished on Sunday,
but mid level instability and upper dynamics (particularly upper
divergence in the exit region of a jet streak rounding the base of
the upper low) should support isolated thunder in the afternoon
through Sunday night. Finally, we should see wome lighter, wrap
around showers linger through Monday into Monday night as the upper
low lifts out to the northeast.
All told, widespread rainfall amounts exceeding 1.5 inches are
expected over the 3 day period. Rain should be spread out enough
over the period to preclude any flooding on larger streams and
rivers, but some localized flooding in urban areas is possible given
the potential for stronger convection on Sunday and Monday. Highs
Saturday and Sunday will be in the 60s, cooling to mid 50s to lower
60s Monday in modest northerly cool air advection on the backside of
the low level circulation.
Cold air will remain bottled up over the northern Conus, so
temperatures will remain mild with as mid level ridging migrates
across the area Tuesday through early Thursday. Abundant sun will
help induce a bit of a warmup, with highs around 60 Tuesday warming
to the mid 60s on Wednesday. A cold front will be approaching on
Thursday, which looks to be mostly dry and we will still be shielded
from arctic sir in the wake of the front, so highs should still
reach the upper 50s to lower 60s.
-- End Changed Discussion --
.AVIATION /18Z TODAY THROUGH MONDAY/...
As of 1130 AM Thursday...
VFR conditions will continue through 06Z/tonight. Ceilings will
begin to lower from the SW later this evening and overnight. MVFR TO
IFR conditions expected with areas of rain and fog between 09Z-
15Z/Friday. The rain is expected to end by late morning, with a
return to MVFR then VFR conditions during Friday afternoon.
Long term: VFR conditions will continue into Friday night. However,
a warm front will approach late Friday night and Saturday. This will
bring IFR to MVFR conditions Saturday with areas of rain and fog.
Another system will bring adverse aviation conditions with rain,
fog, low ceilings, and thunderstorm chances Saturday night through