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-- Discussion containing changed information from previous version are highlighted. --
566
FXUS62 KRAH 202315
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
715 PM EDT Fri Oct 20 2017

.SYNOPSIS...
High pressure will extend across the eastern United States through
the weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 325 PM Friday...

High pressure at the surface and aloft will maintain dry and
seasonable conditions across central NC tonight. Similar to last
night, temperatures will fall quickly immediately after sunset
thanks to the dry air in place. Temperatures will cool through the
60s early this evening, and be in the 50s prior to midnight.
Overnight, the normally colder locations will be a solid 4-7 degrees
colder than the urbanized areas. Also, patchy ground fog probable in
vicinity of I-95, though no travel issues/problems expected. Min
temps lower 40s cooler locations to the upper 40s-lower 50s
elsewhere.

&&

.SHORT TERM /SATURDAY AND SATURDAY NIGHT/...
As of 325 PM Friday...

The high pressure system will remain in control of our weather
Saturday into Saturday night. Aside from some passing cirrus aloft,
expect sunny skies and mild afternoon temperatures. Temps will range
from the mid-upper 70s north to near 80-lower 80s south. The sfc
ridge associated with the high will drift offshore Saturday night
through early Sunday. The resultant sely low level flow will advect
enough moisture to yield patchy fog over most of the region by
daybreak Sunday. Not expecting dense fog so no travel issues
anticipated. It will be a bit milder with min temps in the upper 50s
to around 50 nw to the low-mid 50s southeast.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
-- Changed Discussion --
As of 215 PM Friday...

Ridging over the Atlantic coast will shift east and offshore Sunday
as a trough over the Mississippi Valley deepens and a cutoff low
forms over the lower Mississippi valley. Another near perfect "final
fair" day is on tap, with mostly sunny skies and highs climbing to
the mid and upper 70s. Warm air advection will keep mins up
overnight, with Monday morning`s lows mostly in the mid and upper
50s.

Clouds will be on the increase Monday as deepening south to
southwest return flow pumps moisture into the area ahead of a strong
cold front which will be reaching the mountains late in the day. It
will be warm ahead of the front in southerly flow with at least some
filtered sun early in the day, and highs will reach the mid and
upper 70s. Expect scattered showers showers to develop over the
Piedmont, especially in the Charlotte and Triad areas, during the
afternoon, with showers becoming likely Monday night as the front
pushes across the mountains and accelerates eastward. Mins ahead of
the front again will remain mild Monday night...from upper 50s west
to the lower 60s east.

There are model differences in the timing and evolution of the
cutoff low, which will determine mid level dynamics available to
support strong low level forcing ahead of the surface frontal zone.
Even given unfavorable timing=lessened instability, low level
jetting of 50+ knots and strong helicity ahead of the front suggest
a line of vigorous showers/thunderstorms late Monday night in the
west shifting to the Coastal Plain towards mid day Tuesday. Highs
Tuesday will be hampered somewhat by cloudiness, with temperatures
topping out near 70 in the west to 75 in the southeast.

Cold air advection begins to surge into the area Tuesday night, with
dry weather returning, though we could see lingering instability
showers as residual moisture is squeezed out of the airmass. Mins
Wednesday morning will range from 45 to 50, with highs Wednesday
mostly in the low and mid 60s. Cool air peaks on Thursday, with
morning lows mostly from 40 to 45, with some upper 30s in the
northwest. Highs will be mostly in the lower 60s with some upper 50s
northwest. Friday will warm a bit to the mid and upper 60s as short
lived surface high pressure moves offshore and low level flow
quickly backs from northwest to southwest.
-- End Changed Discussion --

&&

.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
-- Changed Discussion --
As of 715 PM Friday...

Another quiet night across central NC with some MVFR fog the only
possible problem overnight. The most likely locations will be at
eastern terminals, will be patchy in nature and may come and go
throughout the night. Otherwise clear skies and calm winds once
again with high pressure in control.

Long Term: As high pressure slides offshore and a frontal system
approaches from the west, moisture will increase across the area.
Fog and low stratus will be more common through the weekend into
early next week. On Monday night into Tuesday a strong cold front is
expected to cross the area with a threat of showers and
thunderstorms that could possibly lead to an extended period of
adverse aviation conditions. The front is expected to clear out by
Tuesday night leading to VFR conditions for the rest of the week.
-- End Changed Discussion --

&&

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

&&

$$

SYNOPSIS...MWS
NEAR TERM...WSS
SHORT TERM...WSS
LONG TERM...mlm
AVIATION...Ellis