893
FXUS62 KRAH 131712
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
112 PM EDT Mon May 13 2024

.SYNOPSIS...
High pressure will gradually shift off the Southeast coast today.
Low pressure will move in from the west tonight and Tuesday. A cold
front will move through on Wednesday followed by weak high pressure
Thursday.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 945 AM Monday...

There was little change made to the going forecast for today and
tonight. The morning analysis revealed a warm front located across
the deep south, stretching from southern LA into northern FL. High
pressure was centered along the NC/VA coast and will move offshore
the rest of today and tonight. Meanwhile, a convective complex was
presently located across the deep south, north of the warm front.
This convection is largely expected to stay to our south this
evening with dry air still in place. However, recent high-res
models, specifically the HRRR, show some isolated showers making
their way into the southern/western Piedmont by late afternoon and
early evening with weak instability. The 12Z GSO sounding showed a
fair bit of dry air above 850 mb, so most activity, if it reaches
the ground, is expected to be light. A better chance of showers will
come overnight and into Tue morning as the warm front lifts north
into central AL/GA into far southern SC and WAA/isentropic lift
increases over the region. This will also be when low-level warm
front lifts into SC. Highs today should manage to get into the upper
70s to low 80s with increasing high clouds moving in from the
convection to our southwest. Further upstream, an area of low
pressure will move into east-central MO overnight and a weak
front/trough will reach the lower MS valley. Models and CAMs show
another convective complex developing overnight with the front and
strong moisture transport, somewhere over the deep south, perhaps
northern LA to central/southern MS/AL. This convection could
complicate how much shower activity develops here overnight. Lows in
the upper 50s to mid 60s.

&&

.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
As of 210 AM Monday...

Showers are expected especially Tuesday into Tuesday evening before
tapering off from the SW late Tuesday and Tuesday night. PW values
peak Tuesday when 1.7 to 2 inch values are expected. It appears that
a mid-level dry slot will cut off the main bulk of the showers late
Tuesday afternoon and night. There s a chance of a few thunderstorms
Tuesday; however, it is still unclear of how much instability there
will be given the expected rainfall much of the morning keeping it
stable. Highs are expected to reach only the lower to mid 70s
keeping the instability low (with few breaks in the overcast
anticipated). In-situ CAD should also develop with the rain Tuesday
over the Piedmont potentially keeping highs in the 65-70 range.

Rain chances lessen Tue evening/overnight into early Wed as a dry
slot moves in behind 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.

QPF on the order of 0.75 to 1.25 still appears the highest
probabilities (potentially less if convection along the deep south
remains active well into Tuesday).

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
As of 330 AM Monday...

a series of upper level shortwaves will move across the Mid-Atlantic
region over the long term period. This will influence multiple
rounds of showers and storms mid week and over the weekend. At the
surface, a low pressure system over western TN late Tuesday will
move northeast into the OH valley by early Wednesday. As that low
pressure moves NE, a secondary surface low develops along the warm
front over GA/SC coast and by Wednesday morning the secondary low is
expected to be off the NC/VA coast. While the secondary surface low
is shifting offshore, there will be plenty of moisture and lift
across the entire region for scattered to numerous showers and
storms to occur Wednesday. Although, the best chance for storms will
be in the afternoon with peak instability over the Sandhills and
Coastal Plain. As the cold front associated with the secondary low
moves out of the region early Wednesday, the parent low and
associated cold front is expected to move across NC late Wednesday
night. Thursday is expected to be mostly dry with the next frontal
system moving into the region by Friday afternoon. Confidence for
the late week weather pattern is low/medium as models haven`t been
very consistent on the timing of the next frontal boundary.  For
now, have chance PoPs Friday afternoon through Saturday night with
slight chance PoPs on Sunday.

Temperatures mid week begin near climo with highs in the mid 70s NW
to low 80s SE. The weekend becomes above average with Fri/Sat high
temps in the upper 70s to low 80s. Sundays temperatures will depends
on timing of the next frontal passage but for now going with low to
mid 80s across the region.

&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
As of 112 PM Monday...

There is high confidence that VFR conditions will start the TAF
period. A few stray isolated showers could reach the terminals early
this evening, mainly at GSO/INT, but confidence is too low that any
sub-VFR conditions could develop given the dry air over the area
currently. A better chance of sub-VFR conditions will arrive during
the overnight period and into Tue morning/afternoon as a batch of
showers move in from the southwest tied to a warm front and low
pressure. Guidance, including high-res models, are not in agreement
on the timing, placement, and intensity of showers starting early
Tuesday morning and continuing into the afternoon. Therefore,
confidence lowers toward the end of the TAF period. As such, the
main change with this forecast was to slow the onset of IFR
conditions given the model spread/uncertainty. More widespread IFR
could develop after the TAF period with models showing a better
signal at this time.

Outlook: IFR/MFR conditions in showers and storms are favored Tue
afternoon and evening, with the best storm chance at FAY/RWI/RDU.
Sub-VFR conditions and possible fog is then possible early Wed.
Another period of showers or storms are possible Wed aftn/eve, along
with a chance of sub-VFR clouds early Thu. VFR should return Thu
aftn, with the next chance of showers possibly Sat.

&&

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

&&

$$
SYNOPSIS...Badgett
NEAR TERM...Kren
SHORT TERM...Badgett
LONG TERM...CA
AVIATION...Kren