Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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FXUS62 KRAH 281050

Area Forecast Discussion
National Weather Service Raleigh NC
650 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.


As of 400 AM Sunday...

An well defined upper low off the Carolina coast will continue to
drift west beneath the 595dm 500mb ridge over the Mid-Atlantic
states today, while a surface ridge extends into the area from the
Northeast coast. We`re starting to see a little stratus spreading
inland across the coastal plain in northeast flow, which will lead
to mostly cloudy skies through mid-morning as the stratus slowly
burns off. Deeper mixing over the Piedmont may result in dewpoints
in the lower 60s, limiting instability and confining the best
precip chances tot he coastal plain, where increasing moisture and
moderate instability will support scattered storms as the
aforementioned upper low approaches the coast and likely enhances
convection along the seabreeze. Shear parameters are generally
weak, so the main impact from convection will likely be from
brief heavy downpours given PW increasing above 2 inches. The CAMs
are in pretty agreement in the favored area being from
Fayetteville to Goldsboro and to the east. 850mb temps fall from
20C to 18C today, which combined with a little more northeasterly
flow and morning cloud cover, should keep highs a few degrees
lower than yesterday, 89-92.

Convection will generally be diurnally driven today, though the
approaching upper low and easterly low-level flow may continue to
support some inland moving showers into the overnight hours.
Stratus is expected again across the coastal plain by Monday
morning, with lows in the upper 60s and lower 70s.


As of 400 AM Sunday...

Monday looks fairly similar to today, with the upper low drifting
inland over SC and briefly stalling. A strong moisture gradient
will set up again with the surface ridge and deeper mixing in
the west, and better moisture/instability over the coastal plain.
A weak offshore surface low drifting toward the NC coast will have
little impact here, and scattered showers and a few storms will
again be confined to the southern coastal plain. Highs in the
upper 80s and lower 90s. Lows monday night in the upper 60s and
lower 70s.

As of 226 PM SATURDAY...

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.


As of 650 AM Sunday...

Stratus spreading westward from the coastal plain into the Piedmont
may reach RDU before starting to lift through the morning hours.  RWI
and FAY, and maybe RDU, can expect LIFR conditions to slowly improve
to IFR and MVFR by 15z, with generally VFR conditions this
afternoon, outside of a few showers or isolated storms around FAY.
Tonight should be very similar to last night, with stratus spreading
across the area from east to west after 06Z, potentially making it a
little further west and increasing confidence of IFR/LIFR as far
west as RDU.

Outlook: VFR conditions will prevail during the daytime this week,
with early morning stratus/fog likely given continued easterly flow,
and the best chance of afternoon convection will be around FAY and




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