428
FXUS62 KRAH 260201
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
1001 PM EDT Tue Jun 24 2024

.SYNOPSIS...
A surface trough will strengthen over the region through Wednesday
night, ahead of a cold front approaching from the northwest. The
front will drop southward into central NC Thursday and Thursday
night, then lift northward again as a warm front on Friday.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 955 PM Tuesday...

No major changes to the forecast with this evening update. The 00Z
upper air analyses show a low over SC at H25, with generally nwly or
nnwly flow at H5 over central NC. A capping inversion and shallow
but very dry layer around H7 was evident on several 00Z soundings
across the mid-Atlantic/Carolinas. There is still a bit of lingering
moisture at H85, highest over the eastern Piedmont and Coastal
Plain, lower west. At the surface, the dewpoint gradient was still
evident at 01Z, stretching from the southern Piedmont to northern
Coastal Plain, separating low/mid 60s dewpoints from those in the
upper 60s/low 70s. That boundary may retreat further nwwd over
night, with dewpoints mainly in the low to mid 70s expected area-
wide by daybreak Wed. Low stratus will be possible again Wed
morning, mainly east/south of where the dewpoint gradient was as of
01Z. Lows tonight should bottom out in the upper 60s to low 70s.

&&

.SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/...
As of 245 PM Tuesday...

Hot with near Heat Advisory criteria...

Hot conditions look to be close to heat advisory criteria for
portions of the eastern Piedmont, Sandhills, and Coastal Plain
Wednesday afternoon and early evening. The heat index numbers
currently indicate that the urban areas around Raleigh and
Fayetteville should top out in the 100-104 range, just short of
criteria. Surrounding areas are a few degrees lower in the 98-101
range for heat indices. Maximum temperatures should top out between
96-100, except 93-96 in the NW-N Piedmont. We will hold off on a
heat advisory for now, but we may need one for Wednesday in later
forecasts, especially for the urban areas around the Triangle and
Fayetteville. Otherwise, mostly sunny and hot conditions under
strong ridging will continue. There may be an isolated thunderstorm
SE Coastal Plain associated with the seabreeze late day.

Another mid level trough will approach late Wednesday night. There
is a slight chance of showers/thunderstorm NW-N overnight, but
chances appear minimal at this time as models suggest plenty of CINH
overnight. Lows will be mostly in the 70s.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
As of 345 PM Tuesday...

Best chance of showers/storms looks to be Thu/Thu night and Sun/Sun
night, both just ahead of mid level northern stream shortwave
troughs and corresponding surface fronts. Temps will stay above
normal through the weekend, esp Thu and Sat/Sun, before moving
closer to normal Mon/Tue.

Thu/Thu night: A northern stream mid level trough will cross the St
Lawrence Valley into New England/Can Maritimes as the tail end of
this front eases SE through the Carolinas, taking a frontal zone
into our area. The greatest chance for overlapping of strong
heating, high PW (near 2"), and decent surface dewpoints will be
across our S and E, where the majority of NBM members have precip in
the afternoon and early evening. Following this, will have a good
chance of showers/storms NW and likely pops across the SE. The deep
layer bulk shear will be rather low at just around 10-15 kts with
marginal mid level lapse rates, and the moderate SBCAPE does shift E
of I-95 late in the day, so expect a decrease in pops in the evening
and mostly dry weather overnight as the mid levels dry out behind
the mid level trough axis. Expect highs in the lower 90s NW trending
to upper 90s SE. Lows in the upper 60s to mid 70s.

Fri/Fri night: The surface front is likely to settle just to our S
Fri morning, then quickly wash out as the surface high to our N
shifts offshore by afternoon. Behind Thu`s shortwave trough, mid
level ridging spreads in from the SW across the Carolinas and
Southeast coast during this time. PW remains well above normal
across our S and SW where low level confluent flow may help organize
scattered afternoon convection, perhaps aided in part by an upslope
low level component. Will carry chance pops, near climo, across the
S and W with little or nothing in the NE, within the exiting surface
ridge. With near normal thicknesses balanced by abundant heating,
temps should be a bit lower than Thu, with highs around 90 to the
mid 90s. Heat index values are projected to be 100-105 over all but
the NW.

Sat-Sun night: Mid level ridging builds further from the S Plains
across the Gulf states Sat through early Sun, as our thicknesses
rise to 10-15 m above normal with deep mixing and warm/dry mid
levels and weak lee surface troughing over the Piedmont. We should
see highs a bit warmer Sat, from the low 90s NW to upper 90s SE, and
will have near-climo pops Sat focused on the W CWA where mountain
convection may drift late in the day. A potent northern stream
trough that moves from the Upper Midwest and across the N Great
Lakes Sat will move through S Que/St Lawrence Valley and into the
interior Northeast Sun/Sun night, and this plus the westward
propagation of the mid level ridge further W into the S Plains and
lower Miss Valley will induce mid level troughing down the Eastern
Seaboard toward E NC. While SBCAPE and deep layer shear will be
marginal Sun, the increasing and deepening moisture (projected PWs
nearly 2.5") and the approaching surface frontal zone both support
higher pops in the good chance to likely range, highest across the N
Sun afternoon through the evening, with the front pushing to our SE
overnight. Expect highs again from the low 90s NW to upper 90s SE
with high dewpoints well into the 70s, indicative of increased heat
stress as heat index values reach 100-110 over nearly the entire
CWA, all but the extreme NW, both days, although confidence is lower
Sun given the potential for clouds and convection.

Mon-Tue: Pops should be on the low side, 10-25% along the S and W,
as surface high pressure builds in from the N within mid level
troughing. Low level thicknesses suggest highs fairly close to
normal, with highs in the upper 80s to lower 90s. -GIH

&&

.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
As of 745 PM Tuesday...

There is high confidence in VFR conditions to start the TAF period.
The sea breeze in moving inland and has produced a few spotty
showers/storms over the eastern Sandhills and southern Coastal Plain.
We cannot rule out a stray shower or storm at FAY until 02Z, but
confidence was too low to mention anything in the TAF. Otherwise,
the main forecast challenge is the potential for IFR/MVFR stratus
over the eastern terminals (RDU/FAY/RWI) Wed morning. Ensemble
probabilities from the SREF/HREF are highest at FAY for IFR and
lesser at RDU/RWI (MVFR more favored here). The RAP/HRRR/NAM and
GLAMP all indicate at least some sub-VFR restrictions over these
terminals, after which ceilings will lift to VFR between 13-14Z.
Hence, we opted for MVFR TEMPOs at RDU/RWI and prevailing IFR at
FAY. No restrictions are expected at GSO/INT with drier air in
place. There could be a few isolated storms Wed aftn/eve but nearly
all CAMs show limited coverage, so opted to not mention in the TAF
at this time.

Outlook: IFR-MVFR stratus will again be possible at FAY and RWI in
the early morning from Thu through the weekend. A chance of mainly
afternoon-evening showers/storms will also return to the forecast
for Wed night through the weekend, with the relative highest
probabilities on Thu and Sun. Additionally, the development of an
Appalachian-lee, nocturnal low-level jet across and offshore the
Middle Wed night may result in marginal low-level wind shear in cntl
NC during that time.

&&

.CLIMATE...

Record High Temperatures:

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

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

June 27:
KFAY: 102/1998

June 30:
KFAY: 102/2012


Record High Minimum Temperatures:

June 25:
KRDU: 77/2010
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

June 29:
KGSO: 74/2010
KRDU: 78/1914
KFAY: 76/1969

June 30:
KGSO: 74/1936
KRDU: 80/1936
KFAY: 79/1936

July 1:
KGSO: 77/1970
KRDU: 75/2012
KFAY: 76/1990


&&

.RAH WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$
SYNOPSIS...KC
NEAR TERM...KC
SHORT TERM...Badgett
LONG TERM...Hartfield
AVIATION...Kren/MWS
CLIMATE...RAH