Area Forecast Discussion
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FXUS62 KRAH 301844
Area Forecast Discussion
National Weather Service Raleigh NC
245 PM EDT SAT JUL 30 2016
A surface trough and associated weak areas of low pressure will
affect central NC through early next week.
.NEAR TERM /THROUGH TONIGHT/...
As of 1224 PM Saturday...
As of noon, temps are running a degree or two above forecast values.
After adjusting the grids for this trend, it now appears that 3+
hours of 105-108 heat index values will occur across our far eastern
tier of counties. As such, will issue a heat advisory through 8 PM
this evening for Scotland, Hoke, Cumberland, Sampson, Wayne, Wilson,
and Edgecombe counties. Farther west, heat index values expected to
range from 95-103, remaining below our advisory criteria of 105.
Prev near-term disc as of 250 AM...NC continues to be on the very
southern edge of a stronger belt of WSW mid level flow extending
from KY eastward across VA. Another mid/upper level vort max is
forecast to track in the stronger flow to our north this afternoon
and evening. With a surface trough in place through the Piedmont of
VA and NC, scattered convection is expected to develop this
afternoon as strong heating occurs in the very moist air mass in
place over our region.
The convection should fire in the mountains and move eastward, with
the highest POP across the northern sections closer to the stronger
flow aloft. Convection should also favor areas along and east of the
surface trough later this afternoon into the early evening.
Therefore, the highest POP (50) will be across the northern and
eastern zones with lowest POP in the southwest and far southern
Piedmont (20). Locally heavy rain, frequent lightning, and wind
gusts to 40-50 mph should be common with the stronger storms. An
isolated storm may become severe, with localized damaging wind the
main threat (mainly from the Triad to the Triangle and areas
northward). QPF should range upward of 0.50 in the northeast with
locally 1 inch totals.
After the thunderstorms weaken with loss of heating this evening, an
isolated shower or thunderstorm will be possible (20 percent or less
for any one spot). Warm and humid conditions with partly cloudy
skies expected. Lows tonight in the 70s.
.SHORT TERM /Sunday through Sunday night/...
As of 245 AM Saturday...
Most areas will have a good chance of showers and thunderstorms
during the afternoon and evening again Sunday. POP should be 50+
percent, especially aided by the surface trough, an approaching
mid/upper level disturbance rounding the base of the upper trough,
and strong heating in the very moist boundary layer. Highs should
reach the upper 80s to mid 90s before convection overturns the
boundary layer and cools the surface late. A few of the storms
should again be strong and an isolated damaging wind gust or two
can be expected during or just after peak heating.
QPF should average 0.25 to 0.50 with local 1 inch totals expected.
.LONG TERM /Monday through Saturday/...
-- Changed Discussion --As of 245 PM Saturday...
Relatively flat upper level trough will extend from New England into
the Carolinas at the beginning of the week. Perturbations rounding
the base of this trough will interact with available moisture
(precip water values hovering around 2 inches Mon and Tues) and
instability to trigger scattered convection. The bulk of the
convection will occur during the afternoon-early evening hours and
concentrated along a sw-ne orientated surface trough bisecting our
An upper level ridge centered over the lower MS Valley/southern
plains is projected to amplify northward in response to an upper
level low crossing the Pacific NW. This should lead to building
heights over central NC the later half of the work week, leading to
a decreasing chance for afternoon/evening convection.
High temperatures early in the week will average close to normal due
to anticipated cloud and convection coverage. High temperatures will
likely return to above normal levels later in the week as the upper
level ridge exerts its influence on our weather.
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.AVIATION /12Z Saturday through Wednesday/...
As of 650 AM Saturday...
24-Hour TAF period: Generally VFR conditions through noon, then
there is a chance of showers and thunderstorms this afternoon and
early evening. Best chance will be from KGSO to KRDU to KRWI.
A return to VFR conditions tonight and Sunday morning, except for
some early morning LIFR CIGS and MVFR VSBYS between 09Z and 12Z
Looking ahead: There will be a chance for sub-VFR conditions in
showers/storms Sunday afternoon into Monday as the upper trough
settles overhead and a front stalls over central or eastern NC.
MVFR or IFR fog is possible each morning as well.
Heat Advisory until 8 PM EDT this evening for NCZ028-043-078-085-086-