348
FXUS61 KRNK 051745
AFDRNK

Area Forecast Discussion
National Weather Service Blacksburg VA
145 PM EDT Fri Jul 5 2024

.SYNOPSIS...
High pressure offshore will continue to keep muggy conditions
around through tonight, with heat indices exceeding 100 degrees
in the Piedmont. A front is going to reach Ohio/TN Valleys this
afternoon and several impulse will lead to scattered to numerous
thunderstorms. This front will pass across the Mid-Atlantic by
Saturday night into early Sunday. Spotty showers and
thunderstorms will remain in the forecast for early next week as
an upper level trough develops over the central United States.

&&

.NEAR TERM /THROUGH SATURDAY/...
As of 125 PM EDT Friday...

Key Messages:

1) Heat Advisory remains in effect this afternoon/evening for
our foothill and piedmont including Roanoke/Lexington, VA.

2) Strong to severe storms possible this afternoon and evening with
the main threat being damaging winds. Greater chances in the
mountains.


Expect an unstable/humid airmass this afternoon. With plenty of
sunshine this morning, SBCAPEs are forecast to reach 2000-3000
J/kg by mid afternoon across southern VA into NC. There is a
convective system moving across central KY into Mid TN this
morning with an associated MCV. This piece of energy should
reach our mountains by mid afternoon and push into the piedmont
by later in the afternoon. Enough instability and high pwats to
bring a damaging wind threat for any storms that form or move in
this afternoon. Majority of convective allowing models have
storms arriving in our mountains between noon-2pm, then better
chances will be in the 3pm-9pm time frame. Better coverage still
looks across our mountains of SW VA/southern WV into NC, with
less in the piedmont.

High-res models are favoring storms remaining scattered into
late evening over the mountains.

The heat advisory remains with values already hitting 105 or
higher in Brookneal VA and getting close elsewhere east of the
Blue Ridge.

Front expected to push into the Piedmont by late tonight and end
any showers though could see lingering showers in the mountains
into Sat morning. At the same time, winds weaken allow for fog
formation, some of it becoming dense, but given potential cloud
cover and if/where it rains will be patchy dense.


Trends in the models showing a further east/south push to the
deeper moisture but still enough low level moisture and upper
shortwave energy to produce scattered showers/storms Saturday
afternoon southeast of I-81.

After today`s heat/humidity, some reprieve at least across the
mountains/foothills for Saturday as dewpoints drop into the 60s.

Muggy tonight with lows in the upper 60s to mid 70s, then
another very warm to hot day Saturday but again dewpoints to
take some bite out of the heat, with 80s in the mountains, to
lower to mid 90s east. Heat indices could be around 100 or so
southeast of a Buckingham to Danville to Greensboro line.


Confidence in the near term is moderate on storm coverage
through Saturday and severe threat, but higher on
temps/sky/winds.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
As of 1215 PM EDT Friday...

Key Messages:

1. A cold front will bring slightly drier air, limiting showers and
thunderstorms to areas mainly south of Highway 460.

2. Slightly cooler temperatures expected for this weekend, though
these will still be near to slightly above normal.

Looking to Saturday night, weather forecast models are in decent
agreement that a cold front will make slow progress eastward across
central Virginia, where it will gradually stall as it loses its push
of cooler drier air from the northwest. Difficult at this point to
determine where the front will eventually stall. Regardless, it is
expected to remain both close enough and shallow enough to support
lingering showers and thunderstorms through Sunday night, mainly for
areas to the south of Highway 460. Because of light steering winds,
whatever activity that does develop has the potential to produce a
few heavy/prolonged downpours that may result in localized flooding
issues. Enough dry air will be present north of Highway 460 to limit
any coverage of rainfall to isolated pockets at best.

By Monday however, the front will begin to lose its characteristics
and fade/wash out as low pressure passes across the Great Lakes,
dragging another cold front across the lower Ohio River Valley.
Southerly wind flow will increase in response to the area of
low pressure, carrying deeper moisture from the Gulf of Mexico
northward. This will allow for coverage of spotty showers and
storms to expand further northward to include southeast West
Virginia through the southern Shenandoah Valley.

Temperatures will remain near to slightly above normal through the
period.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
As of 1230 PM EDT Friday...

Key Messages:

1. Warmer than normal temperatures with daily storms next week.

Spotty showers and thunderstorms will develop each afternoon through
the middle of the next workweek as a cold front approaches from the
west on Tuesday and eventually stalls somewhere across the Mid-
Atlantic. Coverage of showers and thunderstorms looks highest for
Tuesday as an upper level disturbance passes across the central
Appalachians. Precipitable water values will remain abnormally high
through the period, ranging from 1.7 inches to as high as 2.2 inches
for much of the area, which would support the potential for heavy
downpours, especially from the slower-moving cells.

Warmer than normal temperatures are expected Tuesday and Wednesday.
Near normal temperatures are possible for Thursday.

&&

.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
As of 130 PM EDT Friday...

Mainly VFR through this afternoon, except when any storms move
over a TAF site. Best chance of TSRA 18z-00z especially from
LWB-ROA-DAN and southwest of this line.

Tonight, SHRA/TSRA will continue to affect mainly BLF and LWB as
a front nears. Expect another night where fog develops where it
rained, with higher confidence of sub-VFR, possibly LIFR at
LWB/BCB/BLF, but even with moisture rich environment have fog at
ROA/LYH/DAN as well.

Fog lifts after 12z Saturday with VFR expected. Any
shower/storms will be in the afternoon and generally southeast
of a line from FVX-MTV.

Average confidence in the above forecast.


AVIATION OUTLOOK...

Some lingering showers and sub-VFR possible Saturday evening in
the DAN area. Fog possible through the period in the early
mornings. The pattern stays unsettled such that daily chances
for storms exists. Thinking mainly VFR but sub-VFR when it
storms and any late night fog.

Confidence is moderate for the extended aviation outlook.

&&

.CLIMATE...
As of 300 AM EDT Friday...

Record highs and warmest lows temperatures for July 5th.

Friday 07/05/2024
Site  MaxT Year  HiMin Year
KBLF    93 1948    71 1969
KDAN   103 1919    76 1926
KLYH    98 2012    75 1900
KROA   100 1999    76 2012
KRNK    94 1930    78 1949

&&

.RNK WATCHES/WARNINGS/ADVISORIES...
VA...Heat Advisory until 8 PM EDT this evening for VAZ022>024-
     032>035-043>047-058-059.
NC...Heat Advisory until 8 PM EDT this evening for NCZ003>006-020.
WV...None.

&&

$$

SYNOPSIS...SH/WP
NEAR TERM...WP
SHORT TERM...NF
LONG TERM...NF
AVIATION...SH/WP
CLIMATE...RCS/SH