Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC-- Highlight Changed Discussion --
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FXUS62 KRAH 260705
Area Forecast Discussion
National Weather Service Raleigh NC
305 AM EDT WED OCT 26 2016
Cool high pressure will extend into our region from the north
through tonight, before shifting offshore early Thursday. A cold
front will move into the area from the northwest Thursday night.
.NEAR TERM /through tonight/...
As of 735 PM Tuesday...
Strong high pressure centered well to our north (SW of Hudson Bay)
at 1036+ mb extended south and southeast deep into Florida tonight.
Very dry air was in place over our region and this will be the
case tonight and Wednesday with the high in place. Surface dew points
have come up since sunset a few degrees into the 40s, except 30s NW.
Surface temperatures fall quickly into the lower to mid 50s soon
after sunset and this trend will continue. The only cloudiness
was associated with the stronger mid/upper NW flow aloft extending
from the upper Midwest to the Tennesse and Ohio Valley regions. Most
of these clouds were high clouds and were evaporating as they
encounter the ridging over the eastern seaboard. Any cirrus overnight
should be scattered and thin resulting in no worse than mostly clear
skies. Since winds will go calm the temperatures will fall rapidly
as mentioned above. Some mixing of the dry air just above the
boundary layer will aid in lowering the near surface dew points
as the temperatures fall. Expect lows of 35-42 by daybreak, with
some scattered frost possible in the low-lying areas around our
normally cold spots (including the Roxboro, Louisburg, Rural Hall,
and the Yadkin River valley as well). However, the frost is not
expected to be enough to damage plants/crops that are still yet to
A Warning will not be needed at this time. We will add wording in the
Hazardous Weather Outlook to indicate more in the way of mid 30s in
the rural areas of the Piedmont. No other changes at this time.
.SHORT TERM /Wednesday through Thursday night/...
As of 240 PM Tuesday...
The axis of the weak shortwave ridge will shift eastward over the
Southeast states Wed, as the axis of the Canadian-source surface
ridge begins to shift east and off the East Coast. Expect another
mostly sunny day with below-normal thicknesses indicating highs in
the mid-upper 60s. Milder lows expected Wed night as the return flow
around 925-850 mb anticyclones starts to draw low level moisture
into the area, advecting first into the western CWA. Lows from mid
40s NE to upper 40s and around 50 far south and west. A fast-moving
and strengthening shortwave swinging ESE through the Great Lakes and
Northeast Thu/Thu night will help draw a front into NC from the NNW,
likely not arriving until late Thu night. Have low confidence in our
area receiving any significant precip, considering that the
vorticity will be shearing through the mid level trough axis as it
passes through, the upper divergence will be minor and mostly to our
north, and PW is projected slightly lower than what the models
showed yesterday. That said, forecast soundings do show some
marginal instability late in the day into the evening, although
surface dewpoints may not get quite high enough for anything more
than an isolated storm or two. Will stick with low chance pops (20-
35%), higher north and lower south, from mid afternoon through the
evening, with the isolated thunder risk confined to the north. Warm
sector highs Thu in the 70s. Thu night lows in the 50s, as the front
will be delayed until late and may not work much more southward than
the northern sections of NC prior to daybreak Fri. -GIH
.LONG TERM /Friday through Tuesday/...
-- Changed Discussion --As of 304 AM Wednesday...
Cold front will be near the NC coast by 12z Friday. Lack of CAA will
result in high temperatures on Friday similar to those on Thursday.
Transitory surface high pressure will build across the area in the
wake of the front Friday, before shifting south of the area
Saturday. Another cold front will move quickly through the region
Sunday. Dry westerly flow aloft with little moisture return will
result in a dry passage, followed by weak surface high pressure and
upper level ridging Monday and Tuesday. Temperatures will remain
above normal through the period, with highs in the 70s.
-- End Changed Discussion --
.AVIATION /06Z Wednesday through Sunday/...
As of 105 AM Wednesday...
There is a high probability that VFR conditions will exist across
central NC through tonight as high pressure extends across the
region. This high will drift east late tonight. Southerly return
flow on the back side of this high will advect low level moisture
into central NC, possibly leading to the development of low clouds
or fog by daybreak Thursday. The potential for MVFR/IFR conditions
early Thursday will slowly improve to low end VFR or high end MVFR
ceilings Thursday afternoon when a few showers are expected to occur
ahead of an advancing cold front. This surface front will cross
central NC Thursday night, maintaining a threat for a few showers
and areas of MVFR ceilings.
A return to VFR conditions anticipated for Friday through Saturday
as an area of high pressure builds into the Southeast U.S.