979
FXUS61 KRNK 050742
AFDRNK

Area Forecast Discussion
National Weather Service Blacksburg VA
342 AM EDT Fri Jul 5 2024

.SYNOPSIS...
Exceptionally hot and muggy air continues to pool to the south
of a stationary front situated near the Ohio River. A series of
upper level disturbances passing across the region will trigger
rounds of spotty showers and thunderstorms through Saturday. A
weak cold front will pass across the Mid-Atlantic on 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 TONIGHT/...
As of 235 AM EDT Friday...

Key Messages:

1) Heat Advisory expanded to include a few more counties in VA,
including Roanoke. Otherwise hot and humid.

2) Widespread showers and storms again beginning around noon,
with a few more instances of urban flooding and damaging winds
possible compared to yesterday.

A blocking high stretched from the central Atlantic and into
Africa, and was keeping low pressure in the western Atlantic
from progressing east. This in turn has resulted in slow
movement of the weather pattern affecting much of the eastern
CONUS. Within this broad trough, additional bands of PVA
arriving today will provide lift for convection. Surface low
pressure and associated fronts will near from the west but not
cross until sometime Saturday, but we still have a lee trough in
the area today to provide some focus. Showers and thunderstorms
will develop over the southern Blue Ridge and also arrive from
the west around late morning to noon. Instability will be a
little better than yesterday, and shear will also be improved.
Shear will be marginal and likely not enough for supercells,
but we should see good coverage of multicells producing heavy
rain and also some instances of damaging winds this afternoon
and evening.

Today will be slightly hotter and a bit more humid in spots
compared to yesterday, but overall pretty similar. Current dew
points were in the upper 60s to lower 70s, and southerly winds
today will keep transporting Gulf of Mexico moisture to the
Blue Ridge where it will interact with a lee trough. The 04/12Z
and 05/00Z RNK soundings both had PWATs of 1.72", and this
number beat the old record of 1.71" for that date set in 2013.
NAEFS situational awareness table as well as the ECMWF Extreme
Forecast Index and Shift of Tails point towards continued
anomalous warmth and humidity today. PWATs will likely top
2.20" for parts of the Piedmont, and almost 2" for the
mountains.

Temperatures top out in the mid 80s to low 90s for the mountains,
and the mid to upper 90s for the Piedmont. Lynchburg and Roanoke
will be closest to meeting or exceeding their daily high records;
see Climate section below. A Heat Advisory has been expanded
slightly, and is now in effect for parts of north and north
central NC, the Roanoke area, and parts of Southside VA and the
Piedmont, based on calculated heat indices as high as 109.
Please use caution if working or spending time outside, drink
plenty of water, and do not leave children or animals unattended
in cars.

Overnight, shower and storm coverage gradually shrinks to just
include the western mountains, as a cold front finally arrives
on our doorstep. from the northwest overnight. Expect another
humid and warm night, with widespread fog, some of it dense.

Confidence in the near term is high.

&&

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

Key Messages:

1. Good chances for storms producing heavy downpours with a slow
moving frontal passage Saturday.

2. Temperatures cool off a bit this weekend.

A cold front will be located over the foothills Saturday morning
with convection starting by noon. This front will continue its
slow track across the area, moving over the piedmont in the
evening. With ample moisture and modest instabilities, strong
storms with heavy downpours are possible towards Southside VA
and northwest NC piedmont. By Sunday morning, this front should
be in the coastal piedmont where it will stall and washout.

High temperatures Saturday will range from the low to mid 80s
across the mountains and low 90s in the foothills and
piedmont. Mostly dry weather is expected Sunday which will have
temperatures a few degrees warmer than Saturday.

&&

.LONG TERM /TUESDAY THROUGH THURSDAY/...
As of 210 AM EDT Friday...

Key Messages:

1. Warmer than normal temperatures with daily storms early next
week.
2. Trending cooler and possibly drier by mid week.

An upper level disturbance will approach the Carolina coast
Monday, bring Atlantic moisture into the area.
Diurnal/orographically driven showers and thunderstorms are
expected during the afternoon and evening, mainly along and east
of the Blue Ridge. Models have a cold front moving across the
region Tuesday afternoon into Tuesday night. High pressure
builds in behind the front, keeping most of the area dry going
into next weekend. It is still summer, so can not rule out a few
hit and miss thunderstorms Thursday and Friday afternoon.

Warmer than normal temperatures expected Monday into Wednesday.
Near normal temperatures possible Thursday and Friday.

&&

.AVIATION /07Z FRIDAY THROUGH TUESDAY/...
As of 300 AM EDT Friday...

MVFR to LIFR visibilities and ceilings were due to dense fog
across the area. Very high dew points are the main culprit, and
fog should scatter out later this morning once temperatures
begin to increase. Expect more SHRA/TSRA beginning around noon
for the southern Blue Ridge and BLF, then expanding east to the
remainder of the TAF sites by the afternoon. Coverage will be
expansive with occasional gusty winds and moderate to heavy
rain, bringing visibilities and ceilings down to MVFR or lower
at times.

Tonight, SHRA/TSRA will continue to affect mainly BLF and LWB as
a front nears. Expect another night of widespread fog and
stratus, as low as LIFR.

Average confidence in the above forecast.


OUTLOOK Saturday through Tuesday...

Saturday and Saturday night, a front will cross the area,
bringing additional SHRA/TSRA/fog and MVFR or lower conditions.
Saturday night into Sunday, the remaining SHRA/TSRA will only
affect DAN and perhaps LYH, but fog is expected in locations
where it rained Saturday, and some of this may be dense.

For Monday, the probability for scattered SHRA/TSRA/MVFR
conditions will be mainly confined to the afternoon and
evening. On Tuesday and Tuesday night, another front arrives
from the west, spreading SHRA/TSRA to the entire area, along
with reductions in conditions.

&&

.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 from 11 AM this morning to 8 PM EDT this evening
     for VAZ022>024-032>035-043>047-058-059.
NC...Heat Advisory from 11 AM this morning to 8 PM EDT this evening
     for NCZ003>006-020.
WV...None.

&&

$$

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