-- Discussion containing changed information from previous version are highlighted. --
498
FXUS62 KRAH 240021
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
820 PM EDT Sun Jun 23 2024

.SYNOPSIS...
A hot and humid air mass will hold over the region through early
Monday. A strong mid level trough and accompanying surface cold
front will cross North Carolina late Monday and settle just to our
southeast Monday night, as weak high pressure passes over the area
through Tuesday. Hot and humid conditions will then return Wednesday
and persist into next weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 210 PM Sunday...

Isolated showers have developed across the northern Piedmont during
the past hour or so in an area of sfc convergence ahead an
approaching through that`s currently moving across the Ohio Valley.
Another area of isold showers are ongoing invof coastal areas and
eastern Coastal Plain along the seas breeze.  As the trough
continues to approach... the risk for isold showers will continue
across central NC during the rest of the near term period. The sfc
trough assoc with this system is expected to cross central NC during
the pre-dawn hours overnight, which will set the stage for the
highest PoPs at the start of tomorrow mainly along and east of I-95.
Locations that get to experience one of the these passing
showers/tstms will get some temporary relief from the heat.

Otherwise regarding the heat... will let the current heat advisory
run through its duration and expire at 8 PM.  Lows tonight in the
mid 70s.

&&

.SHORT TERM /MONDAY AND MONDAY NIGHT/...
As of 237 PM Sunday...

An anomalous trough for this time of year will pivot across the
central Appalachians on Monday.  Consequently, flow aloft will turn
wnwly over central NC.

At the sfc, a cool front will move through central NC, perhaps
entering the Triad early Monday morning.  While this front won`t
create a noticeable cool down (high temps will still reach the lower
to mid 90s), it will lead to a considerably drier post-frontal
airmass. Dew points will crash into the upper 50s in the Triad by
the afternoon as flow near the sfc turns wnwly.  Further southeast,
some pre-frontal instability will likely be realized as dew points
remain in the lower 70s early Monday afternoon.  These areas (and
more-so further east along the coast) will be the focus for pre-
frontal and front-induced convection.  As of now, it appears the
best chance for thunderstorms would be in the far southern Coastal
Plain and Sandhills areas (HREF members are in good agreement
simulating the strongest reflectivity cores here and further east
along the coast). Overall bulk-layer shear appears meager (~20 to 25
kts) in this vicinity. However, guidance does simulate DCAPE in the
1000 to 1300 J/kg range. Thus, any deeper core could tap into that
downdraft potential and produce an isolated damaging wind gust.  If
the front were to slow up while crossing the mountains and lag
across central NC, we could see the isolated storm coverage migrate
a bit further north into the central Coastal Plain and northern
Sandhills areas. Those generally north and west of Raleigh should be
too stable for any convection.

While temperatures will once again hover in the lower to mid 90s,
the post-frontal drier air mass should preclude the need for a Heat
Advisory (HI values peak around 100 for those south and east of
Raleigh).  Additionally, the latest output from the experimental
HeatRisk product suggests a category below (moderate) what was
projected for Sunday (Major). Still, given the persistent above
normal temperatures, make sure to practice heat safety if spending a
considerable amount of time outdoors on Monday.

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
As of 222 PM Sunday...

The extended continues to feature hot weather, along with some
chances of storms on the front and back end of the period with a
pair of cold fronts.

We will see a brief reduction in excessive heat Tue behind the cold
front as it settles somewhere over SC into far eastern NC, with high
pressure over the central/southern Appalachians. Highs will still be
in the 90s, although models are indicating dewpoints mixing out in
the upper 50s to mid 60s, resulting in heat indices ranging from 88
to 95. We cannot rule out a stray storm along the sea-breeze over
the far SE but Tue should be mostly dry.

On Wed and Thu, we will be in SW flow aloft ahead of a shortwave
trough over the Great Lakes. A trough axis will extend over the
MS/TN/OH valleys that likely won`t move through until Thu, although
the GFS continues its faster progression relative to the other
guidance. A cold front will approach during the evening hours over
the OH valley, though most guidance keeps us dry until late in the
evening/overnight, with best storm chances over the NW Piedmont. Low-
level thicknesses Wed/Thu will approach some 1430-1440 m, about 20-
30 m above average, easily supporting mid to upper 90s to even low
100s in Raleigh for Wed and heat indices in the low 100s over the
Triangle, Sandhills, and Coastal Plain. A better chance of storms
should exist Thu aftn/eve as guidance has the front and mid-level
shear axis near or just west of the US-1 corridor, along with ample
instability. Have continued high chance PoPs at this time. As a
result, highs Thu could be a few degrees lower with clouds/precip
but heat indices will remain high in the 100-105 range along/east of
US-1. Storm chances should diminish after midnight as the boundary
slides through.

Fri-Sun: A brief reprieve from the heat may be possible Fri as some
of the guidance shows the front settling into SC with ENE flow and
lower dewpoints. Highs from the ensemble data supports low to mid
90s with upper 90s heat indices. The heat, however, is expected to
return over the weekend as much of the ensemble data shows the mid-
level 595+ dm ridge building back east from the southern Plains.
This should bring back mid to upper 90s for highs and heat indices
over portions of the area between 100 and 105 degrees. As for rain
chances, guidance continues to show a second cold front/trough
approaching late Sun, with the GFS/CMC most bullish on rain chances.
Other ensemble members show continued ridging, with the front hung
up to our NW. For now, will hedge with low chances until there is
better agreement.

&&

.AVIATION /00Z MONDAY THROUGH FRIDAY/...
-- Changed Discussion --
As of 817 PM Sunday...

Through 00Z Monday:  Isolated showers/tstms are possible across
central NC tonight ahead of an approaching trough. These storms may
briefly reduce cigs to MVFR along with variable wind directions;
otherwise, generally VFR conditions can be expected. SSW sfc winds
around 10kt with some higher gusts up to 15kt will persist through
sunset, then look for winds to remain aob 10kt overnight, with wind
direction gradually shifting to NW around daybreak in the wake of
the passing sfc trough.

After 18Z Monday:  Scattered showers and tstms will be possible
mainly east of I-95 Monday afternoon and evening.  Mostly dry
weather will return by Tuesday morning.  Isolated late day storms
will be possible again mainly west on Wednesday, followed by a
a chance of afternoon/evening showers/tstms late in the week.
-- End Changed Discussion --

&&

.CLIMATE...

-- Changed Discussion --
Record High Temperatures:

June 23:
KRDU: 100/1986, 2024

June 24:
KRDU: 99/2010
KFAY: 102/1914

June 25:
KRDU: 100/1952
KFAY: 102/1914

June 26:
KRDU: 102/1952
KFAY: 101/1951

June 27:
KFAY: 102/1998


Record High Minimum Temperatures:

June 23:
KGSO: 74/2015
KRDU: 77/1890
KFAY: 77/2017

June 24:
KGSO: 76/2015
KRDU: 76/1888
KFAY: 79/2010

June 25:
KFAY: 75/1952

June 26:
KGSO: 74/2010
KRDU: 76/1902
KFAY: 76/1997

June 27:
KGSO: 76/1969
KRDU: 76/1952
KFAY: 77/1998

June 28:
KGSO: 76/1969
KRDU: 76/1952
KFAY: 78/1914
-- End Changed Discussion --

&&

.RAH WATCHES/WARNINGS/ADVISORIES...
Heat Advisory from 11 AM this morning to 8 PM EDT this evening
for NCZ008>011-024>028-040>043-075>078-084>086-088-089.

&&

$$
SYNOPSIS...Hartfield
NEAR TERM...np
SHORT TERM...Luchetti
LONG TERM...Kren
AVIATION...pwb/np
CLIMATE...RAH