Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC
FXUS62 KRAH 270548
Area Forecast Discussion
National Weather Service Raleigh NC
148 AM EDT WED JUL 27 2016
Strong high pressure aloft will extend across the region through
Wednesday, bringing continued hot and humid conditions to central
NC. The chance for afternoon storms will increase toward the end of
the work week.
.NEAR TERM /THROUGH TONIGHT/...
As of 1100 PM Tuesday...
Isolated showers and tstms continue across the Triangle region and
our southwest zones. Latest mesoanalysis shows the BL stabilizing,
and consequently the storms have been diminishing in coverage and
intensity the last few scans. Meanwhile, we`re keeping a close
watch on the line of showers/tstms dropping southward out of sw VA,
as the current progress of these storms suggest they may hold
together as they approach the state line and cross into our northern
zones. Despite the latest hrrr, which doesn`t show much of the
aforementioned line, we`ve increased pops hours across the northern
third of our cwa until 06z to account for the approaching storms.
Then after 06z, pops are tapered to slight chance from the Triangle
northeastward, then dry across our entire cwa after 10z.
Persistence will be followed for lows tonight, in the lower to mid
70s. Temps over much of the CWA won`t drop below 80 until well after
midnight, exacerbating the adverse health effects of this ongoing
.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
As of 345 PM TUESDAY...
The two main concerns for Wed are the storm threat and the heat. The
mid-upper level ridge will remain centered just to our SE while
extending across the Southeast states, while the weak mid level wave
continues to pass by to our north, crossing the mid-Atlantic coast.
Deep layer bulk shear will remain marginal, and the warm mid levels
will continue to curb instability over the southern sections of NC.
But both factors will be sufficient for convection initiation and
maintenance Wed afternoon across the northern CWA. With a
thermodynamic environment tomorrow similar to that of today, we
should again see scattered storms mainly across the north Wed
afternoon, lasting into the evening before weakening and exiting.
Once again, a few strong storms are possible, but weak lapse rates
and marginal winds aloft will limit this potential. A few debris mid
clouds from this evening`s convection may linger early in the day to
temper heating slightly, however thicknesses and forecast soundings
still support persistence, with highs again in the mid to upper 90s,
and dewpoints starting out in the mid-upper 70s before dropping to
70-75 in the afternoon with mixing. Heat index values are expected
to top out near or above 105 over all but the NW Piedmont tomorrow,
so will go forward with another heat advisory, along and east of a
line from Albemarle to Burlington to Kerr Lake. Lows Wed night in
the mid 70s. -GIH
.LONG TERM /Thursday through Tuesday/...
As of 230 PM Tuesday...
Beginning Thursday, the high pressure system gets suppressed ever so
slightly to the southeast and allows the remnants of the frontal
boundary over VA to creep southward, increasing pops a bit for the
northern tier of the CWA but otherwise points south should remain
fairly dry but afternoon showers and thunderstorms will be favorable
east of the Piedmont trough. Thursday night a wave is expected to
develop just north of the area and move northeastward leaving Friday
fairly dry. Afternoon convection will be possible again Friday and
Saturday afternoons as the upper level flow turns more
southwesterly. By Sunday, central NC becomes increasingly squeezed
between a surface high to our southeast and another to our
northwest. This will set up a more active pattern over the area
which will funnel moisture into the area. This should help keep
skies cloudier and bring temps down a few degrees for the beginning
of next week. Early next week an upper trough develops to help push
the frontal boundary through the area and hopefully provide some
relief to temperatures. Until then expect continued highs in the mid
90s with heat index values approaching 105 degrees.
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
As of 145 AM Wednesday...
A lingering cluster of showers of storms is currently moving
eastward across northeastern portions of the area early this morning
and may spark a few showers and storms near KRWI through 08Z.
Otherwise, VFR conditions are generally expected to continue this
morning outside of possibly a brief period of sub-VFR fog/stratus at
KRDU/KRWI around daybreak (thanks to the scatter convection around
these terminals this past evening).
Expect another round of convection this afternoon under similar heat
and moisture conditions, mainly across the northern tier during the
mid/late afternoon...with activity migrating slowly south in the
evening and early night. Winds through the period will be
light...less than 8 KTS...and generally southwest/west-southwesterly.
Outlook: Mostly VFR conditions are anticipated, although late night
and early morning MVFR fog is possible each day through Fri, with a
better chance of sub-VFR fog/stratus Sat/Sun. Isolated to scattered
showers/storms are expected each afternoon/evening through the end of
the week, with increasing chances by the weekend.
Heat Advisory from noon to 8 PM EDT Wednesday for NCZ008>011-023>028-