Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC-- Highlight Changed Discussion --
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FXUS62 KRAH 210044
Area Forecast Discussion
National Weather Service Raleigh NC
845 PM EDT THU OCT 20 2016
High pressure will retreat offshore in advance of a cold front
and upper level low pressure trough approaching from the west
tonight, then cross the area Friday through Friday night. Cool
high pressure will build in from the west over the weekend.
.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --As of 845 PM Thursday...
Overnight will bring a battle of clear skies and radiational cooling
under the high pressure overhead giving way to increasing
cloudiness, a south breeze at 5-10 mph, and a slight chance of
showers late over the west. Temperatures may end up warmer in the
climatological cooler areas of the NW Piedmont early Friday than
in the traditional warmer areas of the Coastal Plain due to this
battle. The result should be temperatures mainly in the lower to mid
60s around 12z. Any shower chances should arrive after 12z. Some low
stratus will be possible late in the NW zones, and some ground fog
and stratus in the east with lingering radiational cooling there
before the south breeze increases.
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.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
As of 320 PM Thursday...
Falling heights aloft with the deepening upper trough, up to 180m
by Friday afternoon, and a cold front accompanied by rather
strong FGEN will help to overcome the overall lack of deep
moisture on Friday, will result in band of showers that will cross
the area between 12Z and 21Z. Instability will be limited,
especially as the front outpaces the better deep forcing, but the
strong FGEN may be enough to squeak out an isolated storm or two,
mainly east of I-95 in the afternoon. Outside of a slightly
heavier shower, qpf will be less than a tenth or two of an inch.
Some gusty northwest winds, up to 25kt or so per GFS/NAM
soundings, will develop behind the front, and may be briefly
enhanced by the increasing anafrontal nature of the precip,
strongest across northern portions of the area.
By all accounts the precip will be east of the CWA by 21-00Z,
with slowly diminishing northwest winds and cold advection
overnight. Lows 43-48.
.LONG TERM /SATURDAY THROUGH THURSDAY/...
As of 315 PM Thursday...
Dry and seasonably cool weather is expected for the weekend
through the middle of the upcoming work week...
The pattern during the period will feature an exiting high amplitude
upper trough early Saturday with a northwest flow aloft expected for
Saturday and Sunday. A dry cold front will drop south across the
region on Monday. Upper level ridging will develop over the Gulf of
Mexico on Monday and Tuesday and shift off the southeast coast on
Thursday. A northern stream trough and the associated cold front
will move into the Great Lakes on Thursday and into the Mid Atlantic
The sensible weather will feature dry weather through the period
with near zero PoPs through Wednesday night. Chilly temperatures are
expected on Saturday and Saturday night as cold air moves into the
region behind the departing cold front. Have lowered temperatures a
bit for both periods with highs now expected between 59 to 64. If
winds decouple on Saturday night, we could have some lows in the
upper 30s across the western Piedmont. Temperatures moderate on
Sunday into Monday ahead of the dry cold front. Behind the front,
cooler air returns with highs in the mid 60s on Tuesday and
Wednesday with morning lows in the mid 40s. Clouds increase on
Thursday ahead of the approaching system with temperatures warming
back up to around 70. -Blaes
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
As of 730 PM Thursday...
VFR this evening as high pressure slowly weakens ahead of a cold
front approaching the TN Valley. A light southerly wind will
continue through the night, and most model forecast soundings
indicate a good chance of IFR or LIFR stratus or fog, with highest
probability at FAY and RWI. A cold front and band of showers should
be just west of INT/GSO by 12Z, moving east to RDU by 15Z. A brief
shower and MVFR conditions is generally expected with this band,
with northwesterly gusts to 25 kt or so behind the front. Each TAF
site should see MVFR conditions during the afternoon as the showers,
and possibly a thunderstorm or two, move east.
Outlook: VFR conditions will return across all of central NC by
Friday evening, with a northwest wind that will remain at 5-10kt
Friday night and increase to 10-15kt, gusting to 20-25kt on
Saturday. Beyond Saturday, VFR conditions will continue, with a dry
backdoor cold front early next week.