Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC-- Highlight Changed Discussion --
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FXUS62 KRAH 211747
Area Forecast Discussion
National Weather Service Raleigh NC
145 PM EDT FRI OCT 21 2016
An amplifying upper level trough and attendant cold front will track
east across the Carolinas today. A cooler and drier airmass will
advect into the region from the northwest in the wake of the
front tonight and Saturday.
.NEAR TERM /TODAY AND TONIGHT/...
As of 1050 AM Friday...
Despite an impressive water vapor signature associated with the deep
upper wave crossing the Ohio/Tenn Valley, there is very little
precip on radar south of Roanoke VA, owing mainly to a lack of deep
moisture with PW at one inch or less. Still, with 170m height falls
at BNA this morning and intense FGEN showing up from 925mb through
700mb, there should be sufficient forcing to spark a band of showers
this afternoon. Latest HRRR runs have shown a small decrease in the
coverage of showers that develop along the cold front, which
currently extends through western VA to just west of the Triad, as
it approaches US 1 around 18Z and I-95 by 21Z. Given the amount of
dry air, the environment will be supportive of some 25-35kt wind
gusts through dry air entrainment and DCAPE increasing to around
800J/KG across the south, but this conditioned on whether or not any
deeper convection can develop without any appreciable instability,
which RAP forecast soundings don`t show much support for.
Changes to the forecast this morning as minor, mainly to reduce POPs
in the west this morning based on radar trends and adjust temps to
the lack of early precip. Have also nudged up sky cover in the
west with the slowly burning off of fog. Highs should still end up in
the upper 60s to upper 70s, with temps starting to fall by mid
afternoon the west.
Expect rapid clearing from west-east 3-6 hrs after the cold frontal
passage at any given location, with clear skies and a NW breeze
prevailing tonight. Lows Saturday morning will be driven by both
cold advection and radiational cooling, ranging from the low/mid 40s
N/NW to mid/upper 40s S/SE. -Vincent
.SHORT TERM /SATURDAY AND SATURDAY NIGHT/...
As of 300 AM Friday...
Cool, clear and breezy today due to cold advection in the wake of an
amplifying upper level wave tracking offshore the Carolina/Mid-
Atlantic coast tonight and Saturday. Expect clear skies and a breezy
NW wind with highs in the upper 50s to lower 60s, coolest NW
Piedmont. Chilly lows sat night in the lower 40s. -Vincent
.LONG TERM /SUNDAY THROUGH THURSDAY/...
As of 315 AM Friday...
Dry and seasonably cool weather is expected from Sunday through mid
week. Gradually rising heights as high pressure builds in from the
south will provide us with a short-lived warming trend Sunday and
Monday, with highs warming to the mid and upper 60s Sunday, and
further into the low and mid 70s on Monday.
A reinforcing shot of dry and cooler air is expected as a cold front
moves south and through the area on Monday. This airmass will be
locked into place through the midweek as high pressure builds south
down the Atlantic coast. Highs Tuesday through Thursday will be
mostly 65 to 70 after morning lows mostly in the mid 40s.
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
-- Changed Discussion --As of 145 PM Friday...
A narrow band of moisture accompanying a cold front crossing the
area should lead to a band of showers and perhaps an isolated storms
this afternoon, mainly east of RDU toward FAY and RWI BETWEEN 18z
AND 21z. MVFR ceilings and wind gusts to 25-30kt will be possible
with the showers, and a winds will shift to northwesterly behind the
front at 12-15kt gusting to near 25kt.
Winds will weaken and become less gusty this evening, but should
stay between 5-10kt out of the northwest, with otherwise clear skies
Looking Ahead: Breezy NW winds will redevelop on Saturday, sustained
at 10-15 kt with gusts up to 20-25 kt, becoming westerly and
weakening Saturday night and Sunday. VFR conditions are expected to
rule for the remainder of the weekend and through the majority of
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