065
FXUS62 KRAH 271519
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
1118 AM EDT Thu Jun 27 2024

.SYNOPSIS...
A mid-level disturbance and surface cold front will move across NC
today. The front will linger across the southern and eastern
Carolinas through early Friday, before lifting back north as a warm
front. A stronger cold front will approach the area on Sunday.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 1118 AM Thursday...

After updating temperatures and dew points for this afternoon with
the latest model data and current observations, thresholds for the
Heat Advisory are no longer expected to meet in the areas that were
previously thought to be in the advisory. With that, cancelled the
Heat Advisory for Scotland, Hoke, Harnett, and Wake counties. The
far SE counties still could reach Heat Advisory criteria as dew
points remain in the mid 70s. Temperatures this afternoon will range
from upper 80s NW to low/mid 90s SE.

While showers are continuing to move across the NW Piedmont region
today, as the boundary shifts southeast it will move into a more
unstable environment in the southeast where we could expected more
isolated to scattered thunderstorms develop. Some stronger storms
across the far south eastern portion of the CWA could become severe
later this afternoon and early evening. Conditions are expected to
begin to dry out beginning in the NW by early evening and continue
that trend southeast through the overnight hours.

As of 445 AM Thursday...A positive tilt, convectively-amplified mid-
level trough, one which includes a prominent MCV now over nern TN,
will move east and across the srn Middle Atlantic and Carolinas
today, then offshore tonight.

At the surface, 08Z data depict a lee trough from cntl NC swwd
through a ~1007 mb lee low over the Upstate of SC and nrn GA. An
outflow boundary, and focus for isolated to widely scattered
shower/storm development, has intersected the trough and extended
from near ASJ to TTA to VUJ in cntl NC. These two features will
merge and become an effective cold front, and nwrn bound of severe
storm potential, that will move sewd and across cntl and ern NC
today. Meanwhile, a couple of synoptic cold fronts stretched from 1)
the lwr Great Lakes wswwd across the OH and mid MS Valleys, and 2)
the nrn Middle Atlantic coast swwd through a ~1007 mb low over cntl
MS, to the lwr MS Valley, respectively. The two will merge in the
post-effective frontal regime over the Middle Atlantic and move swd
in backdoor fashion across VA and nrn NC tonight.

A combination of morning stratus over cntl NC, now developing in
both the rain-cooled, post-outflow regime over the nrn NC Piedmont
and in the maritime tropical (70s dewpoints) ahead of it, and also a
multi-layered mid/high-level cloud band accompanying the approaching
mid-level trough, will result in cloudy or mostly so conditions to
start the day. A differential heating zone will probably develop
along the sern edge of these clouds from cntl SC to sern NC and
contribute to additional frontogenesis along the aforementioned
effective frontal zone (merged lee trough/outflow), with the hottest
(mid 90s) , most humid, and unstable conditions preceding it through
early this afternoon. Scattered, deeper convection will likely
develop along and ahead of this boundary and congeal into line
segments or a broken line with strong to locally damaging wind gusts
as it moves through the Coastal Plain/ern Sandhills and to the coast
through early-mid afternoon, augmented by lift ahead of the
approaching MCV and mid-level trough.

As that activity moves toward the coast, partial clearing will
probably result wwd across cntl and wrn NC later this afternoon; and
this will allow for stronger diurnal heating into the upr 80s to lwr
90s and weak late day destabilization there. Isolated to widely
scattered showers and storms will probably result in that regime and
continue through early tonight.

Overall, the combination of clouds and convection/outflow will favor
less hot than previously forecast temperatures; and when factoring
in mixed dewpoints that will again decrease into the mid 60s to
around 70 F this afternoon, also lower than previously forecast, the
risk of reaching or exceeding Heat Index values of 105 F appears low
except for perhaps in Cumberland, Sampson, and Wayne Co. It will
nonetheless be hot, with Heat Index values around 100; and given the
consecutive days of heat with Heat index values having been
consistently 102-110 F, and still with moderate to major HeatRisk,
the Advisory will remain in place. A slightly cooler and less humid
airmass behind both the effective front of today and synoptic front
tonight will favor low temperatures in the upr 60s to lwr 70s for
most.

&&

.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
As of 315 AM Thursday...

Cannot rule out a stray thunderstorm Friday morning across southern
counties, but the chance for a thunderstorm should spread across the
entire region Friday afternoon as today`s cold front lifts back to
the north. In addition, an upper level shortwave still appears
poised to bring a chance of thunderstorms across western counties
overnight. In the northwest, highs should be similar to today`s
values, in the upper 80s to lower 90s. In the southeast, highs
should be about 5 degrees cooler than today, reaching the lower to
mid 90s. Heat index values should peak near 100.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
As of 315 AM Thursday...

Sat/Sun: Increased pops Saturday afternoon as ensembles have become
a bit more generous with coverage of precipitation, although
deterministic models are a little more reluctant to do so. Pops
settle down Saturday night before increasing again as a cold front
moves from the Ohio River Valley southeast across the state. Have
continued with likely pops, and this front appears as if it may be
the best chance for rain in the next seven days. Highs will be well
into the 90s each day along with heat index values over 100 degrees.
The values should be highest on Sunday, although the arrival of
showers/thunderstorms could temper these readings.

Mon/Wed: The front will be reluctant to move through, and have
maintained chance pops across generally the southern half of the
forecast area Monday afternoon and just slight chances across
southern tier counties Tuesday afternoon. As the front slides south,
a surface high will build in from the north, allowing for flow out
of the north and a brief relief from the heat. The predicted high at
RDU on Monday, July 1 is 87 degrees, which would break a forecast 18
day string of 90+ highs. By Wednesday, the high moves offshore,
allowing a southerly wind to develop again and raise highs back into
the 90s everywhere.

&&

.AVIATION /12Z THURSDAY THROUGH MONDAY/...
As of 800 AM Thursday...

An area of MVFR ceilings now over the srn Sandhills and srn Coastal
Plain, centered around FAY, should lift and scatter to VFR through
~14Z. Meanwhile, a mid-level trough, embedded disturbances, and
multi-layered mid/high-level ceilings now all centered over wrn NC,
will move east and across cntl-ern NC today. The airmass ahead of
the trough and an accompanying surface cold front will destabilize
weakly and support the development of showers over the Piedmont and
RWI through the late morning-early afternoon, while it will
moderately destabilize and support the development of storms from
near FAY to the coast during the early-mid afternoon. Partial
clearing in the wake of this main area of of precipitation may
support the development of more-isolated, weaker storms over the
Piedmont late this afternoon and eventing. IFR-MVFR stratus will
again be possible especially at FAY and RWI Fri morning.

Outlook: IFR-MVFR stratus will be possible area-wide Sat-Sun
mornings, followed by a good chance of mainly afternoon-evening
showers/storms Sunday.

&&

.CLIMATE...
Record High Temperatures:

June 27:
KFAY: 102/1998

June 30:
KFAY: 102/2012

Record High Minimum Temperatures:

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

&&

Heat Advisory until 5 PM EDT this afternoon for NCZ042-078-088-
089.

&&

$$
SYNOPSIS...MWS/Blaes
NEAR TERM...CA/MWS
SHORT TERM...Green
LONG TERM...Green
AVIATION...MWS
CLIMATE...RAH