Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC-- Remove Highlighting --
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FXUS62 KRAH 280803
Area Forecast Discussion
National Weather Service Raleigh NC
403 AM EDT SUN AUG 28 2016
High pressure will persist over the region through today. An upper
level disturbance over the Atlantic will then drift west along the
Carolina coast Monday and Tuesday
.NEAR TERM /THROUGH TONIGHT/...
As of 1018 PM Saturday...
Convection continues to wane with lingering isolated storms drifting
slowly westward over the central/western piedmont before diminishing
all together as low-level surge of lower theta-e air and increasing
CIN advects into the area behind a weak surface front moving in from
the ne. This nely low-level flow could also result in the
development of some low stratus and/or fog across the NC Coastal
Plain during the predawn hours, possibly spreading westward into the
Central Piedmont/Triangle area aoa daybreak.
Lows tonight 70 to 75, coolest across the ne.
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
As of 350 PM Saturday...
Surface high pressure centered over southern New England will
strengthen and nose southward into the Carolinas Sunday. This sfc
feature will extend across our Piedmont counties. Associated
subsidence should initially limit mixing which may allow low clouds
to linger until late morning/mid day. Otherwise, presence of sfc
ridge should inhibit convective development in the afternoon hours.
Over the southern coastal plain and the sandhills, modest moisture
advection courtesy of an upper level low off the SC coast coupled
with afternoon heating should trigger scattered convection. Expect
the greatest concentration to occur immediately se of our region
though 30-40 percent coverage still possible over parts of our se
Anticipated cloud cover Sunday morning will limit sunshine. this
should to afternoon temps not quite as hot/oppressive as the past
couple of afternoon. High temps upper 80s-lower 90s.
Again, most of the convection will dissipate with loss of heating.
Could see another round of overnight low clouds, though it may be
limited to the se half of the forecast area. Low temps upper 60s nw
to the low/mid 70s se.
.LONG TERM /TUESDAY THROUGH SATURDAY/...
-- Changed Discussion --As of 355 AM Sunday...
WV imagery this morning depicts an increasingly well-defined mid to
upper level low off the SERN U.S coast. The forecast models continue
to indicate this feature will drift W --around the SRN periphery of
the initially strong sub-tropical ridge centered over the Middle
Atlantic states-- and stall along the SERN U.S.
coast early this week, before shearing out and lifting away from the
region through the middle of the week.
The presence of this mid-upper low, and a NRN stream trough forecast
to migrate across the NERN U.S through early week, will cause the
preceding sub-tropical ridge to succumb over the Middle Atlantic
states and ultimately split, with one center expected to retrogress
into the central U.S. and the other retreat into the central N.
Atlantic Ocean. A broad trough will develop between the two /over
ERN U.S./ through the end of the week.
This pattern aloft will play an important role in what becomes of
the now well-advertised tropical wave along the NRN coast of Cuba
this morning, which the models now generally agree will enter the
ERN Gulf of Mexico early to mid-week. Significant model spread
regarding the track and timing of the associated low develops
thereafter, though it seems reasonable that low will eventually be
influenced by the aforementioned ERN CONUS trough aloft and be drawn
NEWD through or along the SERN U.S coast, with an associated
increased probability of rain, through the end of the forecast
Of greater predictability will likely be a NRN stream cold front
forecast to settle through the SRN Middle Atlantic states and
Carolinas Thu-Fri, with an accompanying chance of convection
maximized in central NC Thu-Thu night. Cooler and drier conditions
in post-frontal high pressure ridging across the Middle Atlantic
region would follow, though the duration of this post-frontal regime
will hinge upon what happens with the tropical low and associated
moisture potentially approaching from the south later Fri and Sat.
-- End Changed Discussion --
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
As of 200 AM Sunday...
Early showers and storms have pushes west through the southern
Piedmont and conditions are mostly VFR across the area at 06Z. Skies
have mostly cleared across eastern NC, which may lead to some fog
after 08z, though northeasterly flow may favor more low clouds than
fog, possibly as low as LIFR. Confidence is pretty high that RWI
and FAY will see IFR or LIFR conditions by 09z. To the west, RDU
may end up right on the end of the low clouds, but sub-VFR vsbys
will still be possible at RDU, GSO, and INT given earlier rainfall.
If stratus does indeed develop over the coastal plain, models
suggest it will be slow to lift through the morning hours, with a
period of MVFR ceilings as far west as RDU between 12z and 15z.
Scattered storms will likely develop later this afternoon, mainly
from FAY to RWI and to the east.
VFR conditions are expected to prevail across central NC through
most of the upcoming work week. There will be a good chance for
early morning IFR/low end MVFR conditions each day due to low clouds
and/or fog. In addition, there will be scattered showers and storms
each afternoon, with the highest concentration expected in the
vicinity of KFAY.