Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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FXUS62 KRAH 251052

Area Forecast Discussion
National Weather Service Raleigh NC
652 AM EDT THU AUG 25 2016

High pressure will extend across the region through the remainder of
the week, as a strong upper level ridge builds overhead.


As of 345 AM Thursday...

On the eastern periphery of a 596m ridge at 500mb, water vapor
imagery and dynamic trop maps depict a compact tropopause
disturbance diving south across the area this morning. This has
only resulted in a few extra clouds and will go mostly unnoticed.
the aforementioned ridge will build eastward over the TN Valley
today, continuing the warming trend and dry conditions over
central. Some CAMs suggest convection over the higher terrain
will progress southeast into the Piedmont late this afternoon,
but limited moisture and instability will make it hard for much
more than an isolated storm to reach the northwest Piedmont. Highs

The surface ridge axis will shift east tonight, favoring a little
better cooling over the coastal plain, with lows ranging from the
upper 60s to around 70 east to west.


As of 345 AM Thursday...

The center of the upper ridge -forecast at 594dm- will shift east
and be centered over southwest VA on Friday, bringing the 850mb
thermal ridge across northwest NC and southern VA. 850mb temps
around 21C favor highs in the upper 90s, and while mixing may not be
quite that deep, highs should be on the upper end of guidance, 93-
96. dew points creeping back into the lower 70s area while will
spell a return of humid conditions and heat indices back around
100F. A weakening cold front is forecast to drop into VA Friday
evening, but ahead of the front lows on Friday night will be in the
lower 70s for most areas.


AS OF 355 AM Thursday...

Continued hot on day 3/Sat, but with moderating temperatures and
increasing focus on the tropical N. Atlantic and Gulf of Mexico
through early to mid next week.

The models indicate a strong sub-tropical ridge --one characterized
by mid level heights of 587 dm at 500 mb and 325 dm at 700 mb
centered over nrn ms/al per 00z raob data-- will migrate across the
Central Appalachians and Middle Atlantic states through the weekend.
After another associated hot day on Sat, with low level thickness
values and high temperatures similar to or only very marginally
lower than those of Fri, deep layer nely flow around the NEWD-
expanding ridge will shunt the center of the associated heat WWD
into the TN and OH Valleys by Sunday. The models then remain in
relatively good agreement that the ridge will remain centered over
the Middle Atlantic states, though in a gradually weakened state,
through the end of the forecast period. Under the influence of the
ridge, precipitation chances will remain slim, with the relative
highest (slight chance) invof the sea breeze /over ERN NC/ through
at least Mon.

Model spread remains high with respect to the location and intensity
of what ultimately becomes of the area of disturbed weather that Air
Force Reconnaissance is scheduled to investigate in a few hours
between Puerto Rico and the Bahamas. Forecast uncertainty
consequently remains higher than average for the middle of next
week, so no significant changes have been made to the previous
forecast of increasing moisture/clouds/precipitation chances in
central NC Tue-Wed.


As of 645 AM Thursday...

Under strengthening high pressure, VFR conditions and
light/variable or southwesterly wind will prevail through the TAF
period. there is a small chance of sub-vfr vsbys late tonight,
mainly at KRWI, but given the lack of sub-VFR conditions this
morning and little support from model guidance, confidence is very

Outlook: Persistence of high pressure over the region will
continue to promote VFR conditions, with early morning fog
possible each morning.




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