-- Discussion containing changed information from previous version are highlighted. --
543
FXUS62 KRAH 180600
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
200 AM EDT Mon Sep 18 2017

.SYNOPSIS...
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Weak high pressure centered over the Northeast will extend south
down the Appalachians into the Mid Atlantic through Tuesday.
Hurricane Jose will pass well offshore of the NC coast today and
tonight, then drift farther north offshore of the eastern seaboard
on Tuesday.
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&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
As of 933 PM Sunday...

Pressure gradient will tighten overnight and into the day Monday as
Hurricane Jose continues to move north, and remaining well east of
the NC coast. As such, expect the calm to light winds currently
being reported to become northerly at 4 to 7 kts across central NC,
strongest in the east. While this mixing should preclude widespread
fog development, NAM fcst soundings suggest indicate the low-level
moisture along the coast spreading inland and lowering with time.
Otherwise, we will continue to see in persistence in terms of
overnight lows, ranging from 63-64 in the typically cooler spots
to upper 60s SE.




&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
As of 200 PM Sunday...

As Hurricane Jose moves up the east coast there will be little to no
impact for central NC aside from more clouds and the possibility of
some rain band showers moving through the eastern counties but the
results will be inconsequential. There will be some wind gusts up to
15 kts or so mainly out of the NNE. Coolest temperatures will once
again be in the northeast with warmest values in the southwest
Piedmont. Expect highs between 80-85 degrees. Clouds will begin to
recede on Monday night from southwest to northeast and temperatures
will dip into the low to middle 60s.

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
As of 325 PM Sunday...

While there`s a lot to keep our eyes on in the long term period,
central NC will be in between significant weather features for
most of the period. At the start of the period on Tuesday, a
west to northwest flow aloft is expected as weak troughiness
aloft develops extends from Jose southwest into our region on
Wednesday and Thursday. The weakness aloft eventually closes off
near TN/AL on Friday and then drifts west on Saturday. The
lower level flow which is initially northwest to northerly on
Tuesday and Wednesday, becomes easterly on Thursday and Friday.
With limited forcing for ascent, dry and generally fair weather
is expected with temperatures a few degrees above normal.

The forecast become increasingly more complex late in the
weekend into early next week. Jose which may be evolving into a
sub-tropical or post-tropical system appears inclined to head
westerly toward the mid Atlantic coast. At the same time,
Hurricane Maria is forecast to be approaching the
central/northern Bahamas. The interaction of these two systems
and the weakness aloft over the lower MS Valley or Deep South
will have big implications in the sensible weather across the
area on Monday and beyond. For now, followed WPC guidance with
seasonable temperatures and slight chance PoPs on Monday.
-Blaes

&&

.AVIATION /06Z MONDAY THROUGH FRIDAY/...
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As of 200 AM Monday...

An area of high pressure over the southern Appalachians will
maintain a warm and dry weather pattern for most of central NC into
mid week. Hurricane Jose` passing well offshore of the NC coast
today and tonight will tighten the sfc pressure gradient, resulting
in a steady nne sfc flow with sustained wind speeds 7-12 kts
expected, strongest in the coastal plain. Occasional gusts 15-18kts
may occur, again mainly across the coastal plain. This same flow
will maintain a relatively moist layer of air in the lowest 10k ft
of the atmosphere. This will lead to the development of late night-
early morning low clouds and fog, especially across the eastern
counties, or roughly along and east of highway 1, this morning. This
will lead to an 1-3 hour window of IFR/LIFR ceilings in vicinity of
KRWI, and possibly at KFAY and KRDU, around daybreak. Ceilings
expected to gradually lift into the MVFR range after 14Z, then
disperse prior to 17Z.

Afternoon heating along with weak low level convergence due to Jose
may trigger/support isolated showers over the coastal plain this
afternoon. The probability of occurrence at KRWI appears too low at
this time to mention in the forecast.

As Jose` moves farther north Tuesday, the low level flow will
gradually back to a more nwly direction, advecting a drier low level
air mass and inhibiting the formation of low clouds and fog. Thus,
should experience an extended period of VFR parameters across
central NC Tuesday through Friday.
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&&

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

&&

$$

SYNOPSIS...WSS
NEAR TERM...CBL
SHORT TERM...RE
LONG TERM...BLAES
AVIATION...WSS