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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS62 KRAH 200016
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
816 PM EDT Thu Apr 19 2018

.SYNOPSIS...
Cool high pressure will build over the region tonight
through Saturday, and will remain in control through the
weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 130 PM Thursday...

...Frost advisory in effect tonight for the NC Piedmont
and northern Coastal Plain counties...

Rest of today: Surface cold front continues to push SE through the
area, having just pass through the Triangle. Based on simple
extrapolation, the front should be exiting the SE zones by around
19z. The pre-frontal SWLY wind gusts across eastern NC has nearly
matched the post-frontal NWLY wind gust of 25 to 30 kts. These post-
frontal gusts will spread east will continue through the afternoon
and early evening, gradually diminishing overnight.

CAA has kicked in across the NW Piedmont, with temperatures as of
16z observation starting to fall across the Triad. This cooling
trend will spread southeast through the remainder of the afternoon.

Tonight: Continued CAA overnight will result in the first of two
chilly nights to come. While a steady 5 to 7 kt range should
preclude widespread frost development, models are hinting that winds
could decouple the last few hours before daybreak, especially across
the NC Piedmont. This may be allow temperatures to fall into the 33-
36 range in the Advisory area. Scattered frost will be possible in
low-lying and shelter areas. Tender plants may need protection.

&&

.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
As of 235 PM Thursday...

The expansive cP airmass centered over central US will continue
to build east into the region through Saturday. This will
support dry and cool temperatures. Under sunny skies, daytime highs
will average a good 7 to 10 degrees below normal, ranging from
lower 60s NE to mid/upper 60s south. With the sfc ridge axis
drawing closer to the area, conditions should be favorable for
radiational cooling. As such, will undercut statistical guidance
with overnight lows in the lower to mid 30s, which will pose
another threat for frost.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
As of 300 PM Thursday...

The weekend is expected to be dry as surface high pressure moves
into the mid-Atlantic and New England states. With easterly flow
expect temperatures slightly below normal with highs in the mid 60s
to near 70 degrees and lows in the 40s. By Sunday afternoon cloud
cover will begin to increase from the west as the high slides into a
pattern more favorable for cold air damming.

On Monday, attention will turn to a low pressure system crossing the
deep south which will encroach on central NC from the southwest.
With isentropic lift increasing, better chances of some stratiform
rain will come into play by Monday afternoon give or take a few
hours, which is a much better agreement in model timing than prior
simulations. The ECMWF is still the slower of it and the GFS but the
differences are much smaller. Once rain chances begin, expect them
to continue through Tuesday night when the actual low is progged to
cross the eastern half of the state. Lower chances will then
continue through Wednesday and into Thursday morning with wrap
around precip associated with the back side of the surface low as
well as the upper level low which will pass behind the surface low.
Therefore expect wet and unsettled conditions through the bulk of
the week next week with temps highs in the 60s, moderating into the
lower 70s by Thursday. Lows generally in the upper 40s to low 50s.

&&

.AVIATION /00Z FRIDAY THROUGH WEDNESDAY/...
-- Changed Discussion --
As of 815 PM Thursday...

24-Hour TAF Period: High confidence VFR conditions will prevail
through the TAF period. Gusts may persist for the next few hours,
but should abate by 06Z. Beyond that, winds will generally be
northerly at 6-8 kts, briefly gusting a bit in the east between 12Z
and 15Z Friday. -KC

Looking ahead: Expect VFR conditions to persist into the weekend. A
storm system tracking east across the southern US will bring the
threat for widespread adverse aviation conditions in rain Monday
through Wednesday. -CBL
-- End Changed Discussion --

&&

.RAH WATCHES/WARNINGS/ADVISORIES...
Frost Advisory from 4 AM to 9 AM EDT Friday for NCZ007>011-
021>028-038>043-073>076-083-084.

&&

$$
SYNOPSIS...Badgett
NEAR TERM...CBL
SHORT TERM...CBL
LONG TERM...Ellis
AVIATION...KC/CBL