262
FXUS62 KRAH 070427
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
1230 AM EDT Sun Jul 7 2024

.SYNOPSIS...
A weak frontal zone will remain stalled just east of the
Appalachians through early Monday. This front will weaken further
and dissipate Monday, as mid level high pressure builds over the
Southeast states and Carolinas Monday through Tuesday.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
As of 1000 PM Saturday...

A surface boundary is currently situated roughly along I-85 in the
northern Piedmont, with dew points in the upper-60s to lower-70s to
its NW and dew points in the mid-to-upper-70s to its SE. SPC
mesoanalysis still depicts MLCAPE of 1500-2500 J/kg and PW values of
2-2.5 inches ahead of the boundary across the Sandhills and Coastal
Plain, which is where scattered showers and storms continue. A
second smaller area of showers and storms (including a stationary
cell over KGSO) is over the far NW Piedmont associated with higher
effective bulk shear of 20-30 kt. Storms this evening have produced
very heavy rainfall rates as much as 2 to 3 inches per hour, and
with weak southwesterly flow aloft and converging outflow/sea breeze
boundaries they have been slow to move and training. So flash
flooding has been a concern, but storms are exhibiting a weakening
trend which will continue over the next few hours with loss of
daytime heating. An MCV upstream over GA/SC and a continued very
moist airmass may result in some additional light rain/showers
overnight, particularly across southern parts of central NC where
slight chance POPs linger. An isolated storm can`t be ruled out, but
instability will be limited. Lows tonight will be in the lower-to-
mid-70s, still mild with widespread cloud cover, but not quite as
mild as last night.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
As of 230 PM Saturday...

* Showers and storms expected again on Sunday
* Still hot and humid but heat indices will be a bit lower

Sunday`s weather will mirror today`s (Saturday) with a similar
airmass in place featuring 2.25 to 2.5 in PW`s in place, weak
steering flow, and MLCAPEs around 1000-1500 J/KG. In response to
today`s convection, a weak surface trough will be deposited across
the area and should serve to trigger another round of showers and
storms across the area. Meanwhile upstream convection across
portions of AL, SC, and GA and their remnant MCVs could serve to
focus additional convection across the area during the day tomorrow.
The 12Z HREF is suggesting storms could get going early in the day
(15-16Z) especially across the western Piedmont before blossoming
and slowly expanding eastward. As is the case today, storm motions
will likely be slow and convection is likely to be dominated by
pulse-type clusters producing periods of heavy rain and isolated sub-
severe wind gusts. Hard to pin down any specific area for heaviest
rainfall potential but much (if not all) of central NC shares a
similar 50-70 percent chance of precip during the day. Given the
broad area and low confidence in pinpointing a specific area, I will
hold off on Flood Watches. Showers are likely to linger into early
evening before dissipating around midnight.

Thicknesses should be a bit lower and with storms potentially
developing earlier in the day, cloud cover should also be on the
increase. Temps should run about 5 degrees cooler than today with
highs only reaching the low to mid 90s. Heat indices should remain
at or just below triple digits, with the only exception being
portions of the southern Coastal Plain where readings may try and
take a brief run toward 100-103 before clouds, convection, and
outflows bring temps back down.  Lows falling into the low/mid 70s.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
As of 230 PM Saturday...

* Typical summer pattern expected with hot/humid conditions
* Daily diurnal thunderstorm chances, with greatest rain chances
  late in the week

The mid level pattern for much of next week will feature broad
southwesterly flow as the NC becomes positioned between longwave
troughing over the Great Lakes and an offshore ridge. It`s worth
pointing out that there will also be an upper low that lingers off
the NC coast for a period of time this week, but nearly all guidance
suggests it will be drawn southward away from our area and should
not be a player in our weather across central NC. Embedded within
the southwesterly flow aloft will be a series of weak perturbations,
all of which are difficult to track and time their arrival into NC,
but will ultimately promote daily afternoon/evening shower and
thunderstorm chances with areas across the Sandhills and western
Piedmont favored any given day. PW`s next will generally range from
1.75 - 2.25 inches during this time (90-95th percentile) with little
day to day variation while afternoon MLCAPEs should easily climb
into the 1000-1500 J/KG range. In short, precip chances next week
will closely mirror a typical climatological distribution for
early/mid July. An influx of additional moisture aloft late in the
week should support somewhat higher than normal precip chances and
PoPs have been trended upward slightly.

Hot/humid conditions will once again be the theme next week,
although values should be a bit lower than what has been observed
recently. Afternoon highs should reach the low to mid 90s, with the
highest values of the week possible Tuesday into Wednesday. The
arrival of additional moisture (and presumably cloud cover) should
hold temps back a bit (upper 80s to lower 90s) to close out the week
although heat indices could still approach the triple digits given
the humid airmass. Mild overnight lows in the low to mid 70s will
also be common.

&&

.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
As of 1230 AM Sunday...

Adverse aviation conditions are likely to dominate across the
Piedmont terminals (INT/GSO/RDU) through mid morning, with scattered
showers and isolated storms expected to persist here through around
09z, with just isold showers thereafter through the morning. These
sites will also see variable sct-bkn IFR/LIFR cloud bases topped by
bkn-ovc VFR decks through mid morning, although the highest chance
of IFR/LIFR cigs will be 09z-12z. There will be less of a chance of
IFR/LIFR cigs at FAY/RWI. Any fog this morning should be MVFR at
worst and focused in the SW Piedmont, S and W of INT/GSO/RDU. As
cloud bases rise slowly this morning, VFR conditions should return
by 15z areawide, but redevelopment of scattered to numerous showers
and storms is expected by 16z-18z starting first in the W Piedmont
before quickly expanding across all of central NC, lasting through
the afternoon and evening, and aviation interests can expect a risk
of storms, with periods of sub-VFR cigs/vsbys and gusty/erratic
winds, across all terminals during this time, although coverage
should begin to decrease toward 04z. Outside of any storms, surface
winds will be light and variable, mainly from the SW at RDU/FAY/RWI.

Looking beyond 06z Mon, there is a high chance of IFR cigs and MVFR
vsbys in fog developing areawide shortly after 06z, forming first at
INT/GSO then expanding E. VFR conditions should return by 15z.
Another round of scattered showers and storms is expected Mon, with
coverage slightly lower than today. The general pattern of scattered
to numerous showers and storms each afternoon through evening will
continue through Thu, with at least some chance of early-morning sub-
VFR clouds/fog each day. -GIH

&&

.CLIMATE...

Record High Minimum Temperatures:

July 7:
KGSO: 73/2019
KRDU: 77/1900
KFAY: 78/2017

July 8:
KGSO: 76/2010
KRDU: 78/1986
KFAY: 79/2012

July 9:
KGSO: 76/1987
KRDU: 74/2014

&&

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

&&

$$

SYNOPSIS...Hartfield
NEAR TERM...Danco
SHORT TERM...DL
LONG TERM...DL
AVIATION...Hartfield
CLIMATE...RAH