057
FXUS62 KRAH 191828
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
230 PM EDT Fri Jul 19 2024

.SYNOPSIS...
The front that moved into the region yesterday will remain nearly
stationary across the state through the weekend, resulting in
unsettled weather and cooler temperatures.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 1015 AM Friday...

Some minor tweaks were made to the forecast for the afternoon and
evening. The morning analysis revealed the front has sagged south a
bit from the overnight period. It is currently draped mainly south
of US-64, south of the Triangle and pushing into the central Coastal
Plain. Dewpoint values are only marginally lower behind the front,
with some upper 60s in the Triad and toward Roxboro. The main
distinguishable feature is the NE wind shift and slight clearing in
low cloudiness north of the front.

Morning spotty showers have developed along and south of the
boundary, mainly so far across the Coastal Plain near Rocky Mount.
The latest 12z HRRR aligns closely with the 00z HREF, showing
scattered showers and storms becoming more prevalent by the
afternoon and early evening. CAMs suggest coverage of storms could
develop just about anywhere over central NC. However, it does appear
a more focused area of storms would be favored across the southern
Piedmont, Sandhills, and southern Coastal Plain as the models
continue to suggest the front slowly shifting a tad further south
before settling near the Sandhills this afternoon and possibly near
the SC border this evening. Severe threat still looks quite limited,
if any, with shear stronger north of the front. The main factor
appears to still be isolated flash flood potential with still above-
normal PWs and slow storm motions for training potential, focused
across the SE near the front.

Plenty of low clouds persist, especially along/south of the
boundary, so highs might be a tad lower than expected. Though we
expect these clouds to break up or mix out with heating. Expect low
to mid 80s along/north of US-64 and mid/upper 80s south of that
boundary.

Storm coverage may slightly diminish after sunset with loss of
heating, before another batch develops upstream from a disturbance
over MS/AL/GA. That shortwave is forecast to reach western NC and
eastern TN later tonight and overnight. Coverage of storms should be
highest over the western/southern Piedmont, tracking ENE overnight
into the Triad and mainly west of US-1. This batch will also run
into nocturnal stabilization, so weakening of the storm cells are
possible by early Sat. But elevated instability and the mid-level
energy should favor at least 30-60 percent PoPs west of US-1
overnight. Lows should generally be in the upper 60s to low 70s.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
As of 230 PM Friday...

The damp pattern will persist through the weekend, including above-
normal cloud cover and rain chances, and near to slightly below
normal highs. A marginal severe threat persists for Sat, and locally
heavy rainfall will remain possible throughout the weekend.

Sat/Sat night: Rain chances will be high amidst PWs of 2.0-2.3", but
the highest pops are likely to be skewed to earlier in the day than
usual, morning through mid afternoon, as indicated by the HREF local
probability matched mean output. Southwesterly mid level flow over
the region will draw MCVs from the current Gulf Coast convection
northeastward across the western and central Carolinas starting Sat
morning. It`s tough to tell exactly where the weak surface boundary
will be, but the latest RAP runs depict it sitting nearly W-E over
NC as the low-mid level perturbation lifts northeastward. Light low
level winds will limit mass convergence, but this may still play a
role in focusing locally heavy downpours and slow-moving storm
clusters. The RAP output also favors warm rain processes, with an
LCL-0C depth over 4 km, and slow MBE movement will increase the risk
of localized flooding. The risk of strong to severe storms is
supported by an uptick in mid level flow from 15-20 kts to 25-35 kts
Sat, within persistent moderate SBCAPE and beneath a modest upper
divergence max. After high morning-through-midday pops, we may have
a relative lull period for a portion of the afternoon until we see a
redevelopment of scattered convection late in the day and into the
evening, perhaps lasting into the early overnight with at least
marginal elevated CAPE lingering amidst growing CINH. Expect highs
to range from the 80s to lower 90s, with lows in the upper 60s to
mid 70s.

Sun/Sun night: Attempting to pin down convection details (both
location and timing) becomes more difficult by Sun, but we`ll still
be in a regime featuring weak Gulf-source southwesterly low-mid
level flow, between baggy troughing over the E Plains/Miss Valley
and a strong NW Atlantic ridge extending WSW toward FL. Both PWs and
the vertical thermal/moisture profile will likely exhibit little to
no change, although mid level flow will once again weaken, leading
to a reduced threat of strong storms. See no reason to change from
the good chance/likely pops, with continued variably to mostly
cloudy skies. We should see highs in the 80s to near 90 and lows
mostly in the low-mid 70s. -GIH

&&

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

There is minimal change to the long term forecast. A longwave trough
will extend from Quebec south into the Gulf of Mexico, and warm,
moist advection will persist across much of the eastern United
States. Will continue with likely pops during this time period. In
addition, heavy rainfall rates means that isolated flash flooding
will continue to be a threat across the entire area despite the area
being in a drought. Highs should remain near climatology in the
upper 80s and lower 90s.

&&

.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
As of 152 PM Friday...

Generally VFR conditions are expected to start the TAF period. A
stationary front is draped along/south of the northern terminals
(RDU/RWI). Convection has developed along and south of the boundary.
The front and resultant outflow boundaries will favor the best
chance of storms in the first few hours at RDU/RWI and then into the
early to late evening at FAY as resultant outflows and the front
slightly sags southward. At GSO/INT, confidence was low to introduce
thunder given these terminals north of the boundary. Daytime
scattered storms should weaken between 00-03z. A secondary batch of
storms is possible overnight into early Sat as upstream energy lifts
NE from GA/SC and western sections of NC. As the front is progged to
lift slowly northward or remain stationary across central NC, the
best chance for TSRA overnight would be at GSO/INT/RDU, where lift
and instability is more focused. Most high-res guidance suggests
this, but uncertainty in the coverage means that it cannot be ruled
out at FAY/RWI early Sat. Outside of storm chances overnight, CIGs
are expected to lower to IFR to perhaps LIFR, with conditions slowly
rising to MVFR to VFR midday Sat. FAY may see the least CIG
restrictions given it will be south of the front.

Outlook: Showers and storms will continue into this weekend and
early next week as a front stalls over the area and several impulses
track through in the moist flow. Early morning fog and stratus will
be possible each day as well.

&&

.CLIMATE...
Record High Minimum Temperatures:

July 19: KGSO: 75/2016 KFAY: 77/2023

July 20: KGSO: 75/2019 KRDU: 76/2020

July 21: KGSO: 76/2011 KRDU: 78/1932 KFAY: 80/2017

July 22: KRDU: 78/2011

July 23: KRDU: 78/2011

July 24: KRDU: 79/2011 KFAY: 79/1945

&&

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

&&

$$

SYNOPSIS...Green
NEAR TERM...Kren
SHORT TERM...Hartfield
LONG TERM...Green
AVIATION...Kren
CLIMATE...RAH