785
FXUS62 KRAH 300647
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
245 AM EDT Tue Apr 30 2024

.SYNOPSIS...
A deep high pressure ridge will hold over and off the Southeast
coast through this morning. An upper level trough will drift
eastward over the Carolinas this afternoon through Wednesday. An
upper level high pressure ridge will then build over the Southeast
and Carolinas from the west Wednesday night through early Friday. A
weak upper level disturbance will move in from the west late Friday.

&&

.NEAR TERM /TODAY THROUGH TONIGHT/...
As of 225 AM Tuesday...

While a few showers/storms remain possible late today through
tonight, mainly across the S, overall coverage should be low. Deep
ridging is holding over and off the Southeast coast this morning,
allowing for minimal eastward progress of the cirrus blowing off
from the broad convective band now extending from W Lk Erie through
central KY/TN into AL. This ridging aloft will slowly break down and
shift E as mid level shortwave trough seen on GOES layer WV imagery
over N MS approaches the Carolinas today, resulting in an increase
in clouds over our area as the current PW aob 1" gives way to a band
of 1.25-1.4" PW spreading in from the W. But the existing convection
to our west is likely to steadily dwindle as it gets into the W
Carolinas. The shortwave will weaken as it approaches with
decreasing mid level flow, leading to quickly lowering DPVA, while
the upper jet over the Great Lakes decelerates, leading to
diminishing upper divergence as its right entrance region moves in.
And while higher surface dewpoints will spread in from the S and SW,
the overall moisture flux through the low levels will be fairly low,
which should also keep coverage isolated to scattered at most, and
late-day CAPE is expected to be just a few hundred J/kg at best,
with poor deep-layer shear. Latest CAM runs support this scenario
with decreasing convective coverage and intensity as the waning
forcing for ascent and marginally moist column spreads into our
area. Following the overall picture painted by these latest CAM
runs, will spread low chance pops into the W late this afternoon
then track them E through the evening into the overnight, decreasing
to isolated in the process, focused largely along and S of Hwy 64.
WAA balanced by increasing clouds will keep thicknesses largely
unchanged from yesterday, so expect highs from around 80 to the mid
80s, several degrees above normal, highest E where clouds will be
fewest and thinnest for longer today. Lows tonight in the upper 50s
to lower 60s. -GIH

&&

.SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/...
As of 245 AM Tuesday...

Expect a mix of sun and clouds Wed, with scattered mainly afternoon
convection possible across the E. With very weak surface troughing
over the Piedmont, the further-weakening mid level shortwave trough
is expected to be moving into the E Carolinas Wed morning, in tandem
with the eastward push of the 1+" PWs, as mid level ridging and
drier air in the wake of the trough moves into our area from the W.
Forecast soundings from the HREF show well the drying aloft from the
W across the Piedmont/W Sandhills Wed afternoon with deep mixing and
drying surface dewpoints, resulting in little to no CAPE. Further E
in the Coastal Plain, this drying and the exit of the shortwave
trough occurs later enough in the day to allow the daytime heating
to result in 500-750 J/kg of MLCAPE, mostly E of I-95, and some
interaction with a sea breeze may result in storm cluster or two.
Mid level flow will be very weak, though, producing continued low
deep layer shear. Thus, any storms will be poorly organized,
although we could see some gusty winds in/near storms in our extreme
E. Will maintain chance pops just in the E Wed afternoon, ending by
early evening as subsidence spreads in. Highs still above normal, 80-
85, followed by lows in the upper 50s to lower 60s. -GIH

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
As of 240 PM Monday...

...Unseasonably warm through the end of the work week with a
decaying cold front bringing slightly cooler temperatures and
increased rain chances this weekend...


In the wake of the departing shortwave, the subtropical ridge will
again amplify over the Mid-Atlantic into the Northeast through Fri.
Thurs through Fri is expected to be the warmest period in the
extended with highs climbing into the mid/upper 80s. The highly
amplified mid/upper level flow will strengthen surface high pressure
centered over Newfoundland and eastern Ontario while ridging down
into the Mid-Atlantic coast while a decaying cold front approaches
from the west. These boundaries and the flattening of the sub-
tropical ridge will help support diurnal showers/storms possible
into the weekend, with the primary focus around where the
aforementioned boundaries ultimately set up. Confidence on timing,
placement, intensity, is less than average given model guidance
discrepancies. Trended forecast towards diurnally favored
showers/storms during the afternoon, with a lull overnight. Highs
should be tempered a bit due to increasing overall cloud cover and
slightly lower low-level thicknesses as the ridge collapses with
highs ranging from the upper 70s to mid 80s during the weekend.

&&

.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
As of 140 AM Tuesday...

With a couple of low-probability exceptions, confidence is fairly
high that VFR conditions will dominate across central NC from early
this morning through tonight, as deep high pressure sitting just off
the Southeast coast will slowly give was to an approaching upper
level disturbance. Any cloud cover through this morning will be high
thin cirrus, and while isolated patchy ground fog near RWI can`t be
ruled out from 08z-11z, confidence is too low to include in the RWI
TAF. High and mid clouds will slowly spread in from the west from
midday through the remainder of the TAF period, with sct-bkn VFR
cumulus based around 5-6kft possible after 18z esp at western
terminals. The current solid band of showers/storms over central TN
will keep pushing E through today but will decrease in intensity and
coverage, such that only isolated showers/storms are possible moving
into our W sections (INT/GSO) after 21z. With coverage expected to
be low, will include just a VCSH at INT/GSO for now, and while this
isolated activity could spread E into RDU/FAY/RWI after 02z, once
again confidence in this is not high. Surface winds from the SSW or
SW will increase after sunrise, to 10-14 kts gusting to 17-20 kts
after 13z, then decrease to under 8 kts toward sunset.

Looking beyond 06z Wed, bkn-ovc cloud cover is expected through Wed,
but the risk of sub-VFR conditions will be limited to just in and
near isolated to scattered storms, mainly near FAY late tonight
(after 06z until 12z). Additional isolated to scattered storms are
possible E (RWI/FAY) Wed, mainly afternoon. VFR conditions with low
rain chances are expected Wed evening through at least midday Fri.
Sctd shower/storm chances increase late Fri through Sat with the
potential for sub-VFR conditions including early-morning fog. -GIH

&&

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

&&

$$
SYNOPSIS...Hartfield
NEAR TERM...Hartfield
SHORT TERM...Hartfield
LONG TERM...Swiggett
AVIATION...Hartfield