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590
FXUS62 KRAH 240619
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
220 AM EDT Mon Jun 24 2024

.SYNOPSIS...
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A strong mid level trough and accompanying surface front will cross
North Carolina today, then settle just to our southeast tonight.
Weak high pressure will pass over the area late tonight through
early Tuesday, then push quickly offshore late Tuesday, allowing hot
and humid conditions to return for Wednesday. Another front will
approach from the northwest early Thursday.
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&&

.NEAR TERM /TODAY THROUGH TONIGHT/...
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As of 220 AM Monday...

Temps will remain above normal today, although humidity will be
trending lower through the day. A potent mid level shortwave will
move through the eastern Great Lakes, St Lawrence Valley, and
Northeast toward NB/NS through the day. The corresponding surface
front will approach the Appalachians this morning and likely jump
into the prefrontal trough over the NC Piedmont by early afternoon,
before pushing ESE and to our southeast by early evening. As other
shifts have alluded to, this front will be more of a dewpoint front,
with values dropping into the 60s, while the actual temperature
change will be very modest, just a few degrees at most.

It still appears that convection chances ahead of and along the
front will be largely confined to this afternoon over our southeast
half, particularly S and E of Raleigh, a scenario supported by
recent HREF output and several recent RAP runs. The W Piedmont will
see falling PWs and surface dewpoints by midday, limiting afternoon
SBCAPE, with low level flow becoming northwesterly. But from the
Triangle to the S and E, with decent heating and still-elevated
prefrontal dewpoints allowing for moderate SBCAPE by early afternoon
and greatly steepening 925-700 mb lapse rates to 8.5-9.5 C/km, we
should see initially isolated convection grow upscale and become
scattered to numerous as they push SE of Raleigh. With these steep
lapse rate and improving deep layer bulk shear to 25-35 kt along the
southern fringe of the mid level trough, a few intense downbursts
are possible. By early to mid evening, most CAMs depict convection
winding down and exiting as the front starts to settle to our SE and
drier low level air spills in from the NW. A few clouds may linger
overnight across the SE, but otherwise we should see a clearing
trend from the NW with dry weather after midnight.

Given the slightly lower temps (I hesitate to say "cooler") and
lowering dewpoints with enough clouds to temper isolation a bit, we
don`t have heat advisory concerns today, although of course caution
should still be exercised given the prolonged period of above normal
temps. Expect highs today in the lower to mid 90s, and lows in the
mid 60s to lower 70s. -GIH
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&&

.SHORT TERM / /...
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As of 237 PM Sunday...

To be updated shortly.
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&&

.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 /06Z MONDAY THROUGH FRIDAY/...
As of 1250 AM Monday...

VFR conditions will be dominant across central NC for the next 24
hours, with a couple exceptions through early this evening. Isolated
showers over the NE will likely hold N of RWI before exiting in the
next hour or two. MVFR cigs are possible in the far E (RWI) for a
couple of hours near daybreak. Attention then turns to an
approaching front that will move into the area by midday, then move
through the area and push to our SE by mid evening. This will prompt
scattered to numerous storms this afternoon through early evening
across the SE, with gusty/erratic winds in/near storms. The chance
of storms is fairly high near FAY from mid afternoon through early
evening, but lower near RDU/RWI where storms will be more isolated
and occur earlier in the day, in the early to mid afternoon. Any
storms will exit the SE by 02z, leaving VFR conditions through the
end of the TAF valid period. Surface winds will be light from the SW
and WSW through sunrise, then increase to around 10-15 kt with
around 20 kt gusts (stronger near storms) as they shift around to be
from the NW as the front passes through. Light winds from the N and
NE are expected later tonight.

Looking beyond 06z Tue, expect mostly dry and VFR conditions late
tonight through Tue night. Isolated late day storms are possible
late Wed, followed by a better chance of afternoon/evening showers
and storms Thu. Otherwise, outside of any storms, the risk of
widespread sub-VFR conditions is low through Fri. -GIH

&&

.CLIMATE...

Record High Temperatures:

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 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

&&

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

&&

$$
SYNOPSIS...Hartfield
NEAR TERM...Hartfield
SHORT TERM...
LONG TERM...Kren
AVIATION...Hartfield
CLIMATE...RAH