276
FXUS62 KRAH 130046
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
845 PM EDT Sun May 12 2024

.SYNOPSIS...
High pressure will build across the Southeast and Mid Atlantic
region tonight and shift off the Southeast coast through Monday. A
storm system will move in from the west Monday night through
Wednesday, bringing unsettled weather. Weak high pressure moving in
briefly for Thursday will be quickly followed by another storm
system arriving Friday.

&&

.NEAR TERM /TONIGHT THROUGH MONDAY/...
As of 845 PM Sunday...

Quiet and cool night on tap as high pressure remains over the
southern Appalachians. Any residual nwly sfc flow will subside next
hour or so, allowing for some radiational cooling ahead of upstream
cirrus. Cooling will be strongest across the central/northern
Piedmont where temps will dip into the mid to upper 40s. Further
south along the NC/SC border, upstream cirrus will start to trickle
in shortly, which will likely cap lows in the lower 50s there.
Otherwise, expect dry and quiet weather tonight.

Previous discussion for Monday...The surface high will shift off the
Mid Atlantic coast, resulting in the onset of a light SSE/S return
flow late in the day. High and mid clouds will steadily move in from
the WSW through the day as remnant MCVs or residual debris clouds
from TX/Gulf convection pass over the Carolinas. But it will remain
rain-free, with residual dry air in the mid levels (600-700 mb) and
a lack of moisture transport through the low levels. With
thicknesses expected to rise to near normal and less insolation than
we`re seeing today, high temps should be similar, upper 70s to lower
80s.

&&

.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/...
As of 145 PM Sunday...

A closed upper trough over MO Mon night will become an open wave as
it tracks eastward Tue and Tue night into the lower OH valley and
parts of KY/TN. At the surface, guidance shows a Miller B low
pressure tracking from east-central MO into the OH valley during
this period. Downstream of the low, a warm front over GA/SC is
forecast to lift northward Tue night. While there remain some
differences with respect to track/intensity, models show a secondary
low tracking NE along the NW Piedmont and along the VA border at
this time.

Rain chances will overspread the region overnight Mon night and
especially Tue morning/afternoon as moisture transport and
isentropic ascent maximize over the region. Precipitable water
values increase to near record daily maximum values of 1.75 to 2.0
inches. While not a classic setup, there are some indications of a
weak in-situ wedge that could set up over the NW Piedmont Tue as the
secondary low tracks through. As such, most of the forcing north of
the warm front will be isentropically driven but some thunder
chances will exist across our southern zones, mainly south/east of
US-64/US-1 in closer proximity to some surface based instability.
Highs could be tricky in the NW with lots of low clouds/rain around.
We lowered highs to the upper 60s in the NW and mid 70s in the far
SE, but these may need to be lowered if trends favor a wedge setup.

Rain chances appear to lessen Tue evening/overnight into early Wed
as a dry slot moves in from the mid-level shortwave. However,
lingering low-level saturation should favor drizzle/shower chances
over portions of the area, and perhaps some fog. Lows will be in the
low to mid 60s. Rainfall totals could range from half an inch to
three quarters of an inch in the NW to three quarters of an inch to
1.25 inches in the SE by Wed morning.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
As of 355 PM Sunday...

A mid/upr-level trough over the cntl Appalachians vicinity at the
start of the medium range will move across and offshore the Middle
Atlantic through Wed night, during which time an accompanying
surface low will move across and offshore the srn Middle Atlantic. A
trailing cold front will move southeast and across cntl NC during
the afternoon-evening Wed. Progressive shortwave ridging aloft and
underlying, weak surface high pressure will follow for Thu-Thu
night. A perturbed, srn stream-dominated pattern will then prevail
through at least Sat, with a pre-frontal, Appalachians-lee surface
trough in place Fri and the passage of a frontal low and cold front
Sat-Sat night.

Sensible weather related to the pattern described above will feature
areas of light rain and drizzle Wed morning, followed by likely
showers/storms along and ahead of the cold front Wed afternoon-
evening. Veered and generally weak, unidirectional wswly flow
suggests any associated severe weather risk will be low. Dry
conditions will follow through early Fri, followed by at or above
climo probabilities of showers and storms ahead of the the next
system late Fri-Sat evening, and probably drying conditions by
Sunday.

&&

.AVIATION /00Z MONDAY THROUGH FRIDAY/...
As of 720 PM Sunday...

VFR conditions will continue through the TAF period with a steady
increase in upper level cloudiness expected tomorrow. Surface winds
will remain light as they veer towards southerly by Mon afternoon.

Looking beyond 18z Mon, VFR conditions are expected through Mon
evening, although light sprinkles will begin spreading into the
western Piedmont during the evening hours. Widespread rain with a
high chance of sub-VFR conditions and increasing/shifting winds
aloft will overspread the area from SW to NE starting Mon night,
lasting through Tue afternoon. Rain should become lighter and more
patchy Tue evening/night, but sub-VFR fog and low clouds should
linger through Wed morning. A band of showers with brief sub-VFR
conditions is expected to swingHartfield through Wed afternoon/evening. Areas
of sub-VFR clouds are possible early Thu morning, otherwise VFR
conditions will dominate Thu. Scattered sub-VFR showers and storms
are possible Fri afternoon. -GIH

&&

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

&&

$$
SYNOPSIS...Hartfield
NEAR TERM...Luchetti
SHORT TERM...Kren
LONG TERM...MWS
AVIATION...Swiggett/Hartfield