412
FXUS61 KRNK 170030
AFDRNK

Area Forecast Discussion
National Weather Service Blacksburg VA
830 PM EDT Fri Aug 16 2024

.SYNOPSIS...
Unsettled weather expected through the weekend with clouds
and an opportunity for showers and thunderstorms. Drier and
cooler weather will follow after Monday.

&&

.NEAR TERM /THROUGH SATURDAY/...
As of 810 PM EDT Friday...

Key Messages:

1) Showers and thunderstorms continue through midnight

2) Added fog for overnight

3) Low confidence with respect to showers/storms coverage Saturday

Western band of showers and thunderstorms on National Weather
Service radars will continue to track east for the rest of the
evening. Convective allowing models had the storms weakening
and the remnants east of the piedmont by midnight. Have adjusted
the probability of precipitation for these trends.

Also added fog across southern Virginia, in northern North
Carolina and in the valleys west of the Blue Ridge. Dew points
were still in the mid 60s to lower 70s, so enough low level
moisture to support fog overnight, especially where it rained
Friday afternoon and evening.

Previous Discussion
As of 300 PM EDT Friday...

On the weather map, we have high pressure centered along the
Mid-Atlantic Coast. A warm front stretches from the Ohio Valley
into the central Mid-Atlantic with a cold front from the western
Great Lakes to the southern Plains. Warm frontal showers and
storms are advancing across the OH/TN Valleys and will become
more numerous across our CWA this evening, favoring areas west
of the Blue Ridge for the greatest QPF.

The forecast remains a blend of models as they all seem to be
in good agreement in bringing showers/few storms across the
mountains this evening as the warm front advances to the
northeast. The upper flow is diffluent, so activity may persist
through the night. Warm sector airmass is moist with dewpoints
in the upper 60s to lower 70s so expecting a muggy night as
dewpoints to remain elevated. PWATs are forecast near 1.80
tonight so showers/storms will be rain efficient and may contain
torrential downpours. Can`t rule out some localized flooding
but antecedent conditions overall are dry enough to forgo any
headlines. As for severe storms, majority of models are
keeping higher instability along/west of the Appalachians, so
although a strong storm or two may occur, think severe threat
is low...at least for tonight.

By Saturday, the warm front will have moved northeast of the
area with a cold front advancing across the Ohio Valley. The
entire CWA should be in the warm sector, so expecting a
seasonally hot humid day with temperatures near the seasonal
norm for mid-August. Convective allowing models suggest
afternoon deep convection will develop lee of the mountains
across the piedmont, and along the cold front advancing across
the Ohio Valley. Much of our CWA may initially fall between
these two convergent zones, so we may squeak out a mostly rain
free day before activity gets going later in the afternoon.
Attm think the piedmont, along and east of highway 29 will be
an area to watch for storms...the activity developing early to
mid afternoon and moving east. Storms which develop in advance
of the approaching cold front will move into our far western
areas later in the afternoon and during the evening. In general,
expecting a marginal risk for severe weather, wind being the
primary threat. Secondary threat is excessive rainfall, but wind
fields are increasing ahead of the cold front so storm motion
should limit residence time.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
As of 200 PM EDT Friday...

Key Messages:

1: Showers and storms through the weekend

2: Temps mostly around normal

Latest model runs have slowed down an approaching front coming out
of the Great Lakes, through the OH Valley. Frontal passage through
our region will likely be later Saturday evening and into the
overnight period. Accordingly, the period with heaviest and most
coverage for showers has shifted into the Saturday night time frame.
There is a marginal risk of severe thunderstorms for Saturday, so
despite the front potentially missing peak heating on Saturday
afternoon, the front is fairly dynamic and progressive as far as
summertime fronts go. As usual with these events, mountains will be
most likely to see storm formation, and in the post frontal
environment on Sunday, downsloping will provide some suppression for
storms into the Piedmont and Southside. A remaining trough will
continue to encourage precipitation on Sunday, despite a drier post
frontal environment. Monday will see stronger winds, leading to some
upslope shower formation. Temperatures will remain stagnant and
around normal due to the showers and cloud cover holding things
steady.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
As of 230 PM EDT Friday...

Key Messages:

1: Waning precip chances next week

By Tuesday, surface high pressure will take over the synoptic
pattern. It will be centered near the lower peninsula of Michigan,
and as the week moves on, it will drift east, continuing to shield
us and block any precip formation. The next opportunity for rain
could be as late as next weekend, as some guidance indicates an
upper wave over the southeast CONUS. That is a low confidence
opportunity, however, and we could go longer without rain.
Temperatures will be below normal with highs held in the mid to
upper 70s most of the week.

&&

.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
As of 820 PM EDT Friday...

Western band of showers and thunderstorms on National Weather
Service radars will continue to track east for the rest of the
evening. Convective allowing models had the storms weakening
and the remnants east of the piedmont by midnight. MVFR ceilings
and visibility with these showers and storms may impact KDAN,
KBCB, and KBLF before 04Z/midnight.

Ceilings will lower into the IFR to MVFR range overnight and
patchy MVFR fog will develop. Ridges will be in the clouds.
KLWB and KBCB may lower to LIFR in dense fog, but that will
depend on the amount of cloud cover.

VFR conditions return to all local TAF sites around 14Z/10AM
Saturday. The coverage of showers and thunderstorms will be
scattered on Saturday afternoon.

Above average confidence on wind.
Average confidence on ceiling and visibility.

.EXTENDED AVIATION OUTLOOK...

High probability of precipitation arrives late Saturday. Showers
and thunderstorms with MVFR conditions will continue into Monday
morning with the passage of a cold front.

MVFR clouds and upslope showers are expected to remain over the
mountains through Monday. Ceilings should be VFR east of the
Blue Ridge.

Confidence is higher for dry and VFR conditions Tuesday and
Wednesday as high pressure builds in.


&&

.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.

&&

$$

SYNOPSIS...PM
NEAR TERM...AMS/PM
SHORT TERM...VFJ
LONG TERM...VFJ
AVIATION...AMS/EB