811
FXUS62 KRAH 171759
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
159 PM EDT Mon Jun 17 2024

.SYNOPSIS...
High pressure will remain over the Mid Atlantic and Carolinas
through much of this week. Moisture will increase across the area
late this week into this weekend, bringing some increased rain
chances to the Sandhills/Southern Coastal Plain.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 159 PM Monday...

Upper level ridging remains centered over NC this afternoon while
surface high pressure is positioned off the VA coast. Across central
NC, low clouds have been stubbornly persistent across the western
Piedmont and are just now beginning to thin out. This has kept
temperatures down a few degrees across the Triad but it still
appears highs in the upper 80s/around 90 remain on track later this
afternoon.

With strong subsidence throughout the entire column and surface high
pressure offshore, precip will be hard to come by this afternoon.
However, elevated dewpoints have pooled across the Piedmont where
readings are generally in the lower 70s vs the mid 60s to the east.
A few showers could develop this afternoon, mainly near the
mountains, but a few 12Z HREF members suggest the potential for a
stray shower across Forsyth Co later today. The overwhelming
majority of guidance keeps our area dry today but I will maintain 10-
15 percent PoPs across the far western edge of our forecast area.
After 00Z, any remaining showers should dissipate with the loss of
daytime heating, resulting in a dry evening/overnight.

Temps tonight will once again remain mild with lows in the upper 60s
to lower 70s.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
As of 159 PM Monday...

The synoptic pattern will become increasingly warm and dry as we
progress through the week. Mid level heights will continue to rise,
generally reaching 596-597dm by the time we reach the middle of the
week. With the upper ridge parked directly overhead and the surface
ridge offshore, we`ll see a continued period of dry weather with
above normal temps. Guidance is showing an overall decrease in PW`s
across the area throughout the week and it`s conceivable that even
fewer storms will develop across the western Piedmont Tuesday and
Wednesday. Moisture will still pool adjacent to the mountains but
mid level subsidence and increasingly warm 500mb temps will make it
difficult for storms to develop. As such, PoPs will remain in the
single digits or near zero through the middle of the week. Afternoon
temps will reach the lower 90s Tuesday and Wednesday. Overnight lows
Tuesday night will range from the lower to mid 60s, with about 2-3
degrees of warming expected for Wednesday night.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
As of 300 AM Monday...

Still anticipate below normal rain chances for much of this week,
with increasing heat potentially reaching dangerous levels by the
weekend.

Wed-Thu aftn: A strong mid level anticyclone will be stretched
across PA/NJ/MD early Wed. It will remain quite strong through Thu
and drift only slightly S, its center over the Delmarva by Thu
evening with the ridge oriented W-to-E. Meanwhile, at the surface, a
strong high centered out over the NW Atlantic well E/offshore of New
England will continue to extend ESE through NC, weakening a bit
heading into Thu. As we`ll have low level thicknesses slightly below
normal Wed/Thu capped by anomalously warm/dry/stable mid levels and
below normal PW, convection chances will be extremely limited, and
will maintain a pop-free forecast. The long-fetch low level easterly
flow won`t be particularly strong through Thu but may still draw
enough Atlantic moisture into southern NC for a few more clouds
there, but otherwise skies should be no worse than partly cloudy.
The low level thicknesses offset by decent sunshine should result in
temps near to slightly above normal.

Thu evening-Fri: Our focus briefly shifts to a possible low level
inverted trough or a closed surface low that is expected to develop
on the southern end of the surface ridge a few hundred miles E or
ENE of the northern Bahamas by mid week. Such a low or trough, if it
forms, may be tropical (warm core) in nature, not an unexpected turn
of events given long easterly low level fetch, the time of year, the
extremely warm ocean waters, and the models` consensus of very weak
upper level shear in this area. The latest runs of deterministic
models and ensemble systems generally favor an inverted trough
pushing W onto the Southeast coast Fri morning, which could result
in increasing clouds Thu night and a chance of showers and isolated
storms across our SE and far S sections Fri. But there is far from a
model consensus on this, and the low level flow on the NW side of an
onshore-moving trough could actually result in a backing low level
flow in our area to northeasterly with a reinforcement of low level
dryness and stability in central NC. Will lean toward the NBM`s
solution of low chance pops in our SE and S Fri afternoon for now.
With the mid level heat dome drawing closer, expect further warming
Fri to highs from around 90 to the mid 90s.

Sat-Sun: While we`ll start to see rain chances gradually trending
back toward climatology, the big story this weekend will be the
increasingly oppressive heat. Model differences predictably grow at
this range, but most indicate the mid level ridge center drifting SW
and expanding across NC Sat/Sat night before yielding a bit to a
broad northern stream trough and associated surface cold front
tracking through the Great Lakes region by Sun. The surface high
will push further out over the Atlantic, as a lee trough forms
through the W Piedmont well out ahead of the cold front. Our
thicknesses are expected to climb to around 10-15 m above normal Sat
and to 15-25 m above normal Sun, as our dewpoints rise through the
60s into the upper 60s/lower 70s. Shade air temps are expected to
peak at 94-100F both days, with heat indices of 95-106F and warm
lows mostly in the 70s, which when combined with sunshine and a
limited breeze will contribute to an increased risk of heat
illnesses. Regarding convection chances, with the trend to confluent
steering flow from the SSE through SSW and surface ESE flow pulling
in both Gulf and Atlantic moisture, the initially low PW through Fri
will rebound back over 1.5" over our far E and SE Sat and areawide
Sun. This, with lowering heights aloft due to the weakening mid
level ridge and approaching trough, will support small chance pops
mainly across the S each afternoon into early evening. -GIH

&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
As of 110 PM Monday...

MVFR cigs have been stubbornly persistent across the western
Piedmont but are gradually showing signs of thinning out and/or
rising above 3kft. Once they reach VFR (BTWN 19-20z), expect VFR
conditions at all sites through tonight. There are suggestions in
today`s 12Z guidance that additional MVFR cigs will develop at
INT/GSO late tonight but outside of those locations, no weather-
related aviation impacts are expected.

As for storm chances today, most of the ensemble guidance keeps any
storm development west of INT. Can`t entirely rule out a stray
shower drifting through the vicinity but confidence is too low to
introduce in the TAF for this afternoon. Elsewhere it should remain
dry with no storms anticipated.

Outlook: Outside of the potential for morning MVFR cigs, especially
at INT/GSO, VFR weather is expected at all sites through the end of
the week. Moisture should increase late in the week/this weekend
which could promote showers/storms/non-VFR weather at RDU/FAY/RWI at
times this weekend.

&&

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

&&

$$

SYNOPSIS...Leins
NEAR TERM...Leins
SHORT TERM...Leins
LONG TERM...Hartfield
AVIATION...Leins