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601
FXUS61 KRNK 201835
AFDRNK

Area Forecast Discussion
National Weather Service Blacksburg VA
235 PM EDT Fri Sep 20 2024

.SYNOPSIS...
Weak high pressure will remain nestled over the Appalachian
chain through the weekend, maintaining a mix of clouds and
sunshine, in addition to a low probability for rainfall. A cold
front will gradually approach up the Ohio River Valley during
the early half of the next workweek, resulting in a higher
chance of showers and thunderstorms that will persist into next
weekend.

&&

.NEAR TERM /THROUGH SATURDAY/...
As of 130 PM EDT Friday...

Key Messages:

1) Isolated showers and a few thunderstorms will develop this
afternoon into the evening.

2) Fog and low stratus redevelop overnight into Saturday
morning.

3) Confidence is moderate on more widespread convection
tomorrow, but only expecting a few strong to severe cells.

The Mid-Atlantic region remains between low pressure off the
western Atlantic Ocean and high pressure centered over the
southern Plains. This keeps our area in progressive NW flow
through the weekend. Isolated showers and thunderstorms have
begun to develop over the piedmont where more some mid level
energy was streaming by. Otherwise, we may see a few small
cells develop over the mountains and drift south before
dissipating. Lack of significant forcing and moisture will keep
coverage to a minimum this afternoon and evening. These cells
may produce moderate, brief rainfall at times.

Areas of very low stratus/dense fog from overnight dissipated
finally around noon today. Expect this to redevelop tonight and
take until midday Saturday before burning off. Overnight
temperatures will be in the 50s to low 60s.

A little more widespread convection is expected Saturday with
most of the stronger storms to our north and northeast, closer
to the better forcing. However, gusty winds and heavy downpours
will be possible, especially for the mountains beginning in the
early afternoon, and then spreading south into the piedmont of
VA and NC. A few things could keep these storms from being
stronger and/or more widespread here, and this includes
low and mid level capping. This was evident even on this
morning`s RNK sounding and is partly why cumulus fields and
convection are having a hard time developing today. Expect it
to be evident once again on tomorrow morning`s sounding.

Other reasons convection may struggle include the amount of dry
air in the atmosphere and relatively weak shear and instability.
That said, brief heavy rainfall could lead to urban and small
stream flooding, and inverted-V sounding profiles support
isolated damaging downbursts. This activity should weaken after
dark.

Highs Saturday will warm into the mid 70s to the low 80s...with
a few mid 80s possible in urban areas.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
-- Changed Discussion --
... As of 145 PM EDT Friday...

Key Messages:

1: Drier conditions Sunday, followed by a return of showers and
storms Monday

An upper level ridge will nudge its way from the TN Valley to the
northeast and further over our area Sunday. It will be enhanced by a
deepening trough near the Great Lakes, and travel east as a low off
the Atlantic Coast finally begins to make its way into the ocean.
The loss of moisture from the coastal low, and drier air under the
ridge will not support showers on Sunday. A front over the plains
will continue to move eastward, and on Monday we will see scattered
showers and some storms, particularly in the mountains west of the
Blue Ridge.
-- End Changed Discussion --


&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
-- Changed Discussion --
... As of 220 PM EDT Friday...

Key Messages:

1) Low confidence in timing of a frontal passage later this week

2) Daily showers in the pre-frontal and frontal environment

The approaching front out of the plains will provide a setup for
daily showers and storms throughout most of the week. Each
progressing day will see higher PoPs and expanded coverage over the
CWA. At this point, not seeing strong enough kinematic support for
severe weather, but there will be some thunder amongst the showers.
Deterministic models as well as ensembles are having a hard time
picking out when the front could actually make its passage over us.
Run to run, guidance is also changing, and generally for a slower
solution. Lowered chances on Friday as that seems to be the latest
fropa situation. Coming into the latter half of the week, we will be
keeping an eye on the progression of a low pressure system currently
-- End Changed Discussion --

&&

.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
As of 130 PM EDT Friday...

Areas of IFR to LIFR stratus/fog were still dissipating as of
noon. Enough heating has taken place to lift and scatter out
most of it, and trigger cumulus clouds to develop. Isolated
SHRA/TSRA had developed as well. Forcing is quite lacking
today, so not expected much impact at all, even compared to
yesterday. Coverage is low but convection may briefly impact
area terminals. Areas of IFR fog and stratus are likely to
redevelop tonight across the lower Mid-Atlantic and may take
until midday Saturday before burning off.

More widespread SHRA/TSRA is expected Saturday with most of the
stronger storms to our north and northeast, however gusty winds
and heavy downpours will be possible, especially for the
mountains (BLF/LWB followed by KBCB and KROA) beginning around
21/17Z, and moving into the piedmont of VA (KLYH and KDAN) later
in the afternoon.


EXTENDED AVIATION OUTLOOK...

Isolated to widely scattered showers and thunderstorms are
expected again Sunday afternoon/evening. Otherwise, VFR during
the day then areas of MVFR/IFR fog and stratus at night.

Daily chance of showers, thunderstorms, and lingering sub-VFR
conditions continue Monday through at least midweek as a slow-
moving cold front approaches from the west.

&&

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

&&

$$

SYNOPSIS...NF
NEAR TERM...SH
SHORT TERM...VFJ
LONG TERM...VFJ
AVIATION...SH