-- Discussion containing changed information from previous version are highlighted. --
711
FXUS62 KRAH 141708
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
105 PM EDT Fri Jun 14 2024

.SYNOPSIS...
A developing area of low pressure will move northeast just off the
Carolina coast today and tonight. A cold front will move southeast
across NC tonight and into SC and GA on Saturday where it will stall
and linger through the weekend. The front will lift north through
the area as a warm front on Monday.
&&

.NEAR TERM /THROUGH TONIGHT/...
As of 930 AM Friday...

With the morning update, added some sky cover this morning across
northern counties as the forecast called for clear skies and some
mid level clouds have developed. As for rain chances later in the
day, the HRRR remains consistent in not showing much coverage,
although the RAP shows a bit more coverage moving into the Triad
around sunset. For now, only made some minor tweaks along the border
with the Blacksburg office from Winston-Salem to Roxboro in having a
little more coherent area of slight chance pops right around sunset,
but otherwise will wait until additional 12Z model guidance comes in
before making any other changes to the pops. Otherwise the going
forecast appears to be in good shape. Previous discussion follows.

As of 315 AM Friday...

The latest surface analysis shows an elongated low pressure system
organizing off the GA coast early this morning in the vicinity of a
lingering frontal zone. A small and narrow area of high
pressure extends from southeastern VA southwest into southern
NC. In addition, a cold front extends from Lake Ontario
southwest to near KORD and KSTL. The air mass across central NC
has moistened up over the past 24 hours with PW values of around
1.0 to 1.3 inches, close to normal.

A rather vigorous shortwave trough will move from the Great Lakes
this morning to New England late tonight with central NC well
removed from the forcing for ascent with this feature. The
associated cold front will drop southeast across the central
Appalachians late this afternoon and into northern NC this evening
before moving south into southern NC by around daybreak Saturday.
With the absence of deep moisture and forcing for ascent, NWP
guidance only generates a few showers and possibly a storm across
southern VA this afternoon with the convection fading as it moves
into north-central NC. Instability is lacking with the atmosphere
becoming only weakly unstable in central NC this afternoon with
forecast soundings highlighting a narrow CAPE distribution. It`s
worth noting that the greatest instability although limited is
across the Foothills and western Piedmont where the mid levels are
slightly cooler with very little instability to the east near the
coast. In addition, the latest CAM runs show less convective
coverage than the runs 12 hours ago. With this pattern, have opted
to include a slight chance of about 15% of a shower or a storm
across the northern Piedmont this evening.

The latest NWP guidance is rather consistent in forecasting low
level thickness values of 1400 to 1405m this morning, which is
about 5 to 12m warmer than on Thursday which results in highs
about 2 to 4 degrees warmer than Thursday afternoon. This should
translate to highs of 91 at KGSO, 93 at KRDU, and 94 at KFAY
which is about 3 to 7 degrees above average. Dew points this
afternoon should range in the lower 60s which should keep heat
index values close to the high temperatures. Lows tonight will
be a little warmer than previous nights and range in the upper
60s to lower 70s. -Blaes

&&

.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
As of 340 AM Friday...

A northwest flow aloft is expected on Saturday and Saturday night as
the trough moves off the Northeast coast and a mid level ridge
develops across the Southeast centered near northern GA/AL. At the
surface, a cold front will be moving south across southern NC during
the morning and then into northern SC and GA. While drier air will
move into northern parts of NC on Saturday, the air mass across
southern NC will remain warm with low level thickness values
actually warmer than today across the south with thickness values of
around 1415m near the SC border and around 1395-1400m near the VA
border. This will translate into highs of 92 to 95 across southern
NC with cooler highs of 86 to 89 near the VA border. With cooler
temperatures aloft and a warmer boundary layer, the atmosphere
becomes moderately unstable across southern areas on Saturday
afternoon. This may support an isolated thunderstorm across southern
and southeast areas in proximity to the front and the inland
advancing sea breeze although NWP guidance generally lacks much of
precipitation. Lows on Saturday night will be a little cooler than
the previous night and range near average with lows near 60 near the
VA border to the mid 60s across the south. -Blaes
&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
As of 345 AM Friday...

The extended period will be largely warm and dry with no significant
frontal passages, as central NC is under the influence of an
anomalous mid/upper anticyclone that will continue to strengthen,
from 593 dam at 500 mb to as much as 600 dam by midweek. The
anticyclone will initially be centered to our west over the southern
Appalachians on Sunday/Monday before drifting to the northern Mid-
Atlantic and New England from Tuesday through Thursday. At the
surface, high pressure will move off the New England coast on Sunday
and linger in the western Atlantic into midweek, extending SW into
central NC. This will shift the low-level flow over central NC to a
moist SE direction. However, PW values will still only be near to
below normal, and warm mid-level temperatures and subsidence from
the anticyclone should really suppress any convective development. So
the main effect in our region should just be some clouds, including
possibly some low stratus each morning. Upslope showers and storms
may develop each afternoon over the Appalachians, but latest
ensemble guidance really pins the convection near the mountains.
Can`t totally rule out a stray shower or storm drifting into our far
west each day, particularly on Sunday before the flow aloft turns
more easterly, but at this time have a dry forecast through
Wednesday. By Thursday, the anticyclone may be far enough north and
east for some troughing to get back into the area, so carry slight
to low chance POPs in the south and east.

As for temperatures, highs will increase from upper-80s to lower-90s
on Sunday to lower-to-mid-90s on Monday and Tuesday as the ridge
strengthens. The good news is models seem in pretty good agreement
there will be enough mixing to keep dew points from getting too
oppressive, generally lower-to-mid-60s. Temperatures may decrease a
bit by Wednesday and Thursday as the anticyclone moves farther away,
but no significant cooldown is expected. Lows will mainly be in the
mid-to-upper-60s through the period.

&&

.AVIATION /17Z FRIDAY THROUGH WEDNESDAY/...
-- Changed Discussion --
As of 105 PM Friday...

24 hour TAF period: High confidence in VFR conditions through the
next 24 hours. There still remains an isolated chance for a
shower/thunderstorm at INT/GSO through the afternoon/evening, but
chances are too low to include this in the TAF, let alone mention
any ceiling or visibility restrictions. Also do not think that there
will be enough cloud coverage to warrant any persistent ceilings.
Any chance of rain should end by midnight. While the wind is
generally out of the west-southwest right now, a cold front moving
through late this evening into the early morning hours should veer
the wind around to the northwest. The wind will likely continue to
veer to the northeast at all sites after 12Z Saturday, but did not
feel this warranted an additional line in the TAFs at this time.

Outlook: The chance for any rain or restrictions remains minimal
during the next few days with quiet weather expected.
-- End Changed Discussion --

&&


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

&&

$$

SYNOPSIS...Blaes
NEAR TERM...Green/Blaes
SHORT TERM...Blaes
LONG TERM...Danco
AVIATION...Green