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-- Discussion containing changed information from previous version are highlighted. --
993
FXUS62 KRAH 190214
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
1015 PM EDT Fri Aug 18 2017

.SYNOPSIS...
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A cold front will move into the Piedmont overnight. The front will
slowly across the Coastal Plain on Saturday before pushing off the
coast on Sunday.
-- End Changed Discussion --

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
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As of 1015 PM Friday...

A well defined mid level trough encountering the moist and slightly
unstable air mass over central NC will continue to trigger and
sustain scattered convection through the rest of the evening and
into the first half of the overnight. Near sfc atmosphere
stabilizing with loss of heating, so the threat for strong wind
gusts diminishing. Parameters aloft over the northern coastal plain
still support conditions ideal for frequent/abundant lightning with
the storms. While the atmosphere abundantly moist, steering flow in
the the order of 20kts will aid to push the storms along, decreasing
the potential for locally excessive rainfall.

Through 06Z, bulk of the scattered convection will occur in vicinity
of the highway 1 corridor. After 06Z, most of the convection should
occur along and east of I-95.

Sfc cold front attendant with the mid level trough will enter the
northern Piedmont after 06z, and likely bisect the region sw-ne at
daybreak Saturday. A slightly drier more stable air mass will begin
to filter into the northwest Piedmont after 10Z. Otherwise
warm/muggy conditions will persist overnight with temperatures
generally in the mid-upper 70s.
-- End Changed Discussion --

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
As of 300 PM Friday...

The cold front reaches the Coastal Plain Saturday morning and
slowly slips east and moves off the coast by daybreak Sunday.
An upper level trough approaches the region from the OH Valley
on Saturday afternoon with the trough axis moving across central
NC toward daybreak Sunday. A much drier air mass moves into the
region with precipitable water values dropping into the 1.1
(west) to 1.6 (east) range by Saturday afternoon. While a small
threat for a shower or storm lingers across the Coastal Plain
and Sandhills near the cold front, generally dry conditions are
expected elsewhere. The air mass cools slightly with highs
ranging between 88 to 94 degrees Saturday afternoon. Drier air
moves into the area from the northwest Saturday night, and dew
points fall into the mid to upper 60s across the Piedmont and
the lower 70s in the Coastal Plain. This will support much more
comfortable lows in the upper 60s in the Piedmont and lower 70s
in the Coastal Plain. -Blaes &&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
As of 244 PM Friday...

Dry weather is expected on Sunday across all of central NC with a
dissipating front now progged well to our south and rather inactive
westerly flow aloft.  Given the steady-state airmass combined with
ample sunshine, we should easily see highs into the low 90s.

On Monday we`ll see heights rise as the ridge off the SE coast
builds northward.  The sfc pattern will be fairly typical for this
time of year with the sfc high over the western Atlantic promoting a
southerly low level flow over our area.  Forecast soundings show a
notable inversion around H7 with dry air in the mid-levels, and in
some cases (particularly across our southern and eastern counties) a
fair amount of moisture above H4.  Thus with heating, the forecast
soundings suggest a decent amount of shallow cu may form below the
inversion across much of central NC as the afternoon progresses.  To
make matters worse, the soundings also suggest a veil of cirrus, esp
the farther south you go.  If there is any good news, these
soundings do not support rain or deep convection, so will keep PoPs
well below climo for Monday.  So in summary for the eclipse weather,
neither clear nor completely overcast, but rather partly cloudy with
cu briefly obscuring the sun at times, along with some high clouds.
Keep in mind that if you spend any substantial time outside, be
ready for highs in the low-mid 90s with heat index values in the
upper 90s.

Tuesday should be mostly dry as the ridge slowly moves east, but
then rain chances will increase on Wednesday as the next northern
stream short wave moves south and east and pushes a cold front
across our area.  The longwave trough will continue to deepen over
the East, so look for cooler temps by late next week, and perhaps
even a brief break from the high humidity for next weekend.

&&

.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
As of 815 PM Friday...

A broken line of showers and storms will cross central NC this
evening into very early Saturday morning in advance of a cold front.
Heavy rain and gusty winds will be possible with the strongest
storms, with IFR/LIFR conditions possible. The activity is currently
moving through KGSO/KINT now and will affect the eastern TAF sites
generally from 01-05Z. The cold front is expected to move into the
area overnight and slowly move across the area Saturday morning into
the afternoon. We may see some showers and storms develop across far
eastern and southeastern portions of the area Saturday afternoon,
with KFAY standing the best chance of seeing a shower and or storm
during the afternoon (though probabilities will still be fairly low
at KFAY, with a better chance to the south and east of KFAY).

Outlook: VFR conditions are expected on Saturday night and Sunday
with dry weather expected. The threat of late-day storms and some
early-morning fog and stratus will increase on Monday into Tuesday.

&&

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

&&

$$
SYNOPSIS...BLAES
NEAR TERM...WSS
SHORT TERM...BLAES
LONG TERM...NP
AVIATION...BSD/BLAES