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000
FXUS62 KRAH 131926
AFDRAH

AREA FORECAST DISCUSSION
National Weather Service Raleigh NC
226 PM EST Fri Dec 13 2019

.SYNOPSIS...
Weak low pressure will move through the Southeast today. High
pressure will build in Sunday through Monday. Another frontal system
will approach the area Tuesday, moving through central NC mid-week.

&&

.NEAR TERM /THROUGH SATURDAY/...
As of 225 PM Friday...

A developing off the GA coast this aft/eve will slide northeast
along the Southeast and mid-Atlantic coastline through tonight. Even
as the low approaches the Carolinas, the wedge may linger over
portions of the Triad and NW Piedmont of NC this evening, eroding as
this first low exits to the northeast. Meanwhile, the initial Gulf
low will follow the same track as the initial low, along the
Carolina coast. There may also be a brief lull in the precipitation
around midnight or so between the two lows. However, another round
of rain is expected overnight before the Gulf low finally lifts
through and out of the area Saturday. When all is said and done, 1-
2.5 inches of rain is expected to have fallen since early this
morning. Areas of fog are likely to develop overnight, becoming
dense at times. Any fog that develops will lift and scour out on
Saturday. Lows tonight will be very similar to highs, mid 30s NW to
around 50 degrees SE. Highs on Saturday expected to be in the 50s as
long as the wedge completely erodes tonight.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
As of 205 PM Friday...

The mid level shortwave trough will pivot ENE away from NC Sat
night, leaving 100-150 m height rises and clearing/drying conditions
as the steering flow flattens briefly to a fast nearly zonal flow.
We are likely to see mid-high clouds streaming across the area
overnight as a 140+ kt upper jet noses into the region, but overall
skies should be fair with nearly normal lows in the 30s.

Sun into Mon should be dry and warm, as mild surface high pressure
builds from the Gulf over FL/GA early Sun, then shifts E off the
Southeast coast late Sun into Mon, in response to a large mid level
trough digging over the western and central CONUS and accompanied by
an approaching surface cold front. The approach of this trough will
result in growing ridging aloft over the Southeast. The cold front
looks likely to move into the Mid South region by late Mon; recent
GFS runs have sped up slightly, but all models are in fairly good
agreement on this timing. Models generally agree that appreciable
precip will hold well to our W and NW through 00z Tue. But the low
levels will be moistening as the prefrontal warm/moist conveyor belt
pumps Gulf moisture into the region, so we can`t rule out a few
sprinkles or drizzle late Sun night into Mon. Expect partly cloudy
skies Sun trending to cloudy Sun night/Mon with areas of fog and low
clouds especially Sun night/Mon morning. Expect temps to be steady
or rising Sun night then peaking well above normal Mon, although
warming may be delayed a bit in the NW as the cooler/stable air
retreats. -GIH

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
As of 220 PM Friday...

Rain chances will increase Mon evening and peak late Mon night and
Tue along and just behind the cold front passage, as the upper
trough slowly pushes eastward with a positive tilt. The GFS has sped
up in recent runs, while the ECMWF has trended slower, attributable
in part to their differences in northern stream low/trough
progression over/N of the Great Lakes, so there is still a lot of
uncertainty about timing. But it looks likely that everywhere will
see some measurable rain during this window, and will retain high
pops. The front should be pushing offshore late Tue or Tue evening,
with improving but cooling weather late Tue night/early Wed as an
expansive, chilly high starts to build in from the W. Thicknesses
drop to 25-30 m below normal, so Wed temps should be cool, although
the true Arctic air will hold to our N. Dry weather and fair skies
should hold through Fri, with moderating temps, as the departing
trough leads to rising heights with the surface ridge holding over
the Eastern Seaboard. A mid level shortwave trough may approach from
the W late Fri, however with timing differences and the lack of
available moisture, impacts should be minimal. -GIH

&&

.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
As of 1225 PM Friday...

24 hour TAF period: Primarily LIFR/VLIFR conditions expected through
tonight as the rain continues over central NC and areas of fog
develop overnight. Brief improvements to IFR (primarily visbys) are
possible, but not likely. Some improvement is expected after
daybreak Saturday as visbys improve to MVFR/VFR and cigs begin to
lift. Rain will gradually move out of the area during the aft/eve,
but cigs could remain MVFR or lower through the remainder of the TAF
period.

Looking ahead: Expect periods of MVFR cigs on Saturday eve/night as
a trailing shortwave moves through the area. Some patchy fog will be
possible in the pre-dawn hours Sunday morning, but otherwise VFR
conditions should prevail Sunday and Monday. Another frontal system
will approach from the west mid-week, resulting in a return to sub-
VFR aviation conditions and rain.

&&

.RAH WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$
SYNOPSIS...KC
NEAR TERM...KC
SHORT TERM...Hartfield
LONG TERM...Hartfield
AVIATION...KC