098
FXUS62 KRAH 041913
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
310 PM EDT Thu Jul 4 2024

.SYNOPSIS...
Surface high pressure will extend across the western Atlantic and
Deep South through tonight and then weaken and shift east on Friday.
A cold front will approach the region from the northwest late Friday
and then move into the Carolinas during the weekend.
&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
As of 245 AM Thursday...

* Hot and humid conditions will continue into this evening.
* Scattered thunderstorms will drift into north-central NC this
  afternoon and move into the NC Piedmont this evening as they
  weaken.
* Storms will be efficient in producing strong gusty winds.

The latest surface analysis continues to show high pressure centered
across the western Atlantic extending west into the eastern
Carolinas and the eastern Gulf of Mexico. A cold front extends from
the eastern Great Lakes southwest across the western OH Valley and
into the MO Valley. A weak lee trough extends from central VA into
central NC. Further aloft an anomalously strong west to east 500mb
ridge was centered across the Deep South. The main belt of
westerlies extend from a trough across across western KS/NE and into
the Great Lakes.

The air mass across central NC this afternoon is warm and relatively
moist with PW values of around 1.75 inches or around 120% of normal.
The air mass has become moderately unstable in most locations with
MLCAPE values of around 1000-1500 J/Kg. Mid level laps rates are
rather anemic but low level lapse rates have steepened as the
boundary layer has heated with temperatures in the lower to mid 90s
in many locations.

Regional radar imagery showed an isolated shower or two along the
lee trough near Hoke and Scotland Counties and in Halifax County.
This precipitation will likely be short lived and transient. Other,
more notable and likely impactful areas of convection have developed
across the Blue Ridge in northern NC and southwestern VA. This
convection is likely being driven by differential heating and some
mid level disturbances moving around the periphery of the upper
level ridge.

The thunderstorms along and just east of the Blue Ridge will shift
south and east into northwest Piedmont and VA border counties over
the next few hours. The convection may strengthen a bit as it
approaches the Triad between 4 and 8pm. With a lack of forcing for
ascent, the convection will begin to weaken later this evening as it
approaches the Triangle and Rocky Mount areas between 6 and 10pm
with the convection dissipating before midnight as it moves toward
the Fayetteville area. The best chance of precipitation will be
across the northern tier and Triad areas. With strong heating today
and deep boundary layer mixing, inverted-V thermodynamic profiles
are expected supporting DCAPE in excess of 1000 and likely resulting
in efficient production of strong gusty winds with convection.

Skies will be partly cloudy overnight with a mix of some patchy high
clouds and perhaps some patchy stratus or low clouds across the
south and southeast. It will remain warm and muggy tonight, with
lows mainly in the mid 70s. -Blaes

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
As of 310 PM Thursday...

* Heat Advisory is in effect for Friday with dangerously hot
  conditions expected.
* Widespread heat index values of 105 to 109 are expected for
  several hours during the afternoon.
* Temperatures wont fall back into the lower 80s until around
  midnight.

The mid and upper level ridge across the Deep South will persist but
deamplify a bit on Friday as a broad trough and embedded closed low
move across the northern Plains. At the surface a lee tough will
extend south across the western Piedmont of VA and the Carolinas. A
cold front will advance slowly east into the eastern OH and TN
Valleys on Friday afternoon. The air mass across the Carolinas warms
additionally on Friday with morning low level thickness values
ranging in the 1420 to 1428m range along with 850 mb temperatures
that climb to between 20 and 24 C Friday afternoon. This air mass
should support highs in the mid 90s to around 100 with low 100s
expected in some of the typically hotter locations such as KRDU,
KFAY, and KMEB. Combining the hot temperatures with elevated dew
points will result in widespread heat index values of 105 to 109.

Scattered thunderstorms are apt to develop across western NC during
the afternoon and slowly push east into the western Piedmont late in
the afternoon and especially during the evening. Other more widely
scattered thunderstorms may develop across the northern Coastal
Plain. The airmass across central NC will be moderately to strongly
unstable with MLCAPE values ranging from 1500 to 2500 J/kg. Profiles
suggest a primary threat of damaging winds with steep low level
lapse rates and elevated DCAPE. The convection is apt to continue
into the evening before dissipating overnight. Outside of the
thunderstorm cooled areas, temperatures are likely to linger in the
upper 80s to lower 90s through at least mid evening and wont fall
into the lower 80s until around or a little after midnight. Low
temperatures should eventually fall into the mid to upper 70s by
daybreak Saturday. -Blaes
&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
As of 226 PM Thursday...

Saturday may offer an opportunity for above-climo PoPs with
scattered showers/tstms as a prefrontal trough moves into our area
ahead of an upper s/w trough moving NE across the eastern Great
Lakes region.  The rain will be welcome due to recent dryness, but
also to limit the intensity of the daytime heating, particularly
across our western and Triad zones where rain will arrive earlier in
the afternoon.  There, highs in the lower 90s...vs upper 90s east
where rain will arrive later in the day.

The aforementioned trough will weaken and stall Saturday night with
a broad pressure trough lingering over the Piedmont for Sunday. This
pattern will yield another round of afternoon/evening scattered
showers/tstms with highs a bit lower than prev days (in the lower
90s) given the anticipated cloud cover and scattered showers/tstms.

Next week`s pattern will be very near climo, both daily PoPs and
daytime high temps, given an active daytime Piedmont trough which
will result in scattered showers/tstms each afternoon and evening
and resulting clouds, rain, and outflows which will keep temps in-
check near, or just above climo values.

&&

.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
As of 230 PM Thursday...

Widely scattered thunderstorms will drop southeast from the NC
mountains and southern VA and move into the northwest Piedmont,
Triad area and VA border counties affecting the KINT and KGSO
terminals between 19 and 00Z. A wind gust to near 35kts and a brief
MVFR restriction mainly for visibility is expected with the stronger
storms. These storms will weaken as they near the KRDU and KRWI
terminals between 22 and 02Z with the precipitation dissipating
before reaching KFAY. Otherwise, VFR conditions are expected tonight
and into early Friday afternoon. Southwest to westerly winds at 6 to
10kts are expected this evening with light southerly winds tonight
into early Friday.

Outlook: There`s a chance of late afternoon and evening
thunderstorms on Friday with a slightly better chance of showers and
thunderstorms Saturday into Tuesday as cold front drops into the
region and stalls across the area. In addition, some late night and
early morning fog and stratus is possible on Saturday and
especially Sunday and Monday mornings. -Blaes
&&

.RAH WATCHES/WARNINGS/ADVISORIES...
Heat Advisory from 11 AM to 8 PM EDT Friday for NCZ007>011-
021>028-038>043-073>078-083>086-088-089.

&&

$$

SYNOPSIS...Blaes
NEAR TERM...Blaes
SHORT TERM...Swiggett
LONG TERM...NP
AVIATION...Blaes