606
FXUS61 KRNK 132319
AFDRNK

Area Forecast Discussion
National Weather Service Blacksburg VA
719 PM EDT Sat Jul 13 2024

.SYNOPSIS...
A weak boundary will linger across the Piedmont into Sunday,
with limited shower and storm coverage. Afternoon thunderstorm
chances can be expected Monday through Tuesday, while another
system brings more widespread rain towards midweek. Temperatures
will increase with heat index values approaching 100 degrees in
Piedmont again for much of next week.

&&

.NEAR TERM /THROUGH SUNDAY/...
As of 715 PM EDT Saturday...

Key Messages:

1) Warm weather continues; humidity remains in check through the
weekend.

2) Isolated convection possible each afternoon....but unlikely to
affect most.

Isolated showers/few cloud to ground strikes observed on
radar/lightning network around Lynchburg. Not much in the way of
coverage and should stay that way into this evening. Skies
overnight expected to be mainly clear with patchy fog toward
dawn in the valleys.

Previous discussion...

Skies are sunny over much of the area, with some daytime cumulus
clouds over the mountains, and additional lower level moisture
over parts of the VA and NC Piedmont.

Upper level flow is more progressive through tomorrow as short
wave energy shifts SE from the western Great Lakes and
Canada, and the blocking high over the Atlantic Ocean is
suppressed. A stationary front just inland from the Mid
Atlantic will shift offshore tomorrow morning as high pressure
builds in. In the meantime, an isolated thunderstorm or shower
is possible this afternoon for the extreme eastern/southeastern
part of the forecast area, where the lower level cloud
cover/moisture intersects the front. There is also an isolated
chance for convection over the southern Blue Ridge. These cells
will weaken with sunset.

Today has been warm but not especially humid, and expect
clearing skies overnight to support lows in the low 60s to low
70s, with patchy fog once again in the morning. Isolated cells
may form again Sunday afternoon, mainly south of I-81, as short
wave energy crosses the area. It will be hot again, but overall
pretty similar to today, with humidity remaining manageable.

Confidence in the near term is high.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
Issued at 111 PM EDT Sat Jan 13 2024

Key Messages:

- Above normal temperatures are expected early next week.

- Heat indices greater than 100 degrees are expected east of the
  Blue Ridge Monday and Tuesday.

- A limited coverage of showers and thunderstorms is possible near
  the Blue Ridge.

Ridging, both at the surface and aloft, will remain the dominant
weather feature for our area heading into early next week.
Despite a lack of forcing, sufficient instability (with most
likely MLCAPE values between 1000-1500 J/kg)could combine with
limited moisture pooling near the Blue Ridge and allow a few
afternoon showers or thunderstorms to develop Monday and
Tuesday. Any convection that develops should be short-lived and
dissipate after the loss of daytime heating.

Of greater importance will be the heat, thanks partially to the
subsident flow and limited moisture. The bottom line (to quote
lyrics from a 40 year-old song) - it`ll be "hot, hot, hot."
Confidence is very high that afternoon temperatures Monday and
Tuesday will likely average 10 to 15 degrees above
climatological norms for mid-July, with highs in the 90s just
about everywhere to start the workweek. Tuesday will be even
warmer; probabilistic guidance indicates a near certainty
(approx. 90% odds) that afternoon temperatures will exceed 95
degrees in the Piedmont and Southside Virginia. In fact, it`s
not out of the realm of possibility that afternoon highs could
flirt with the century mark across parts of Central Virginia
Tuesday afternoon. I`ll keep forecast high temperatures above
guidance values since the deterministic output remains at least
in the upper quartile of the ensemble spectrum.

An increased number of heat-related impacts may be seen as a
result of the hotter temperatures. Heat indices between 100
and 104 will likely be seen by Monday afternoon across the
Piedmont and Southside, as well as parts of the Roanoke and
Shenandoah Valleys. By Tuesday, heat indices will likely reach
or exceed 105 in the aforementioned areas. This may require the
issuance of Heat Advisories across our area at some point Monday
and/or Tuesday.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
Issued at 111 PM EDT Sat Jan 13 2024

Key Messages:

- Above normal temperatures continue through Wednesday, with heat
  indices above 100 still possible.

- Shower and thunderstorm probabilities return for the middle and
  latter half of the upcoming week.

Ridging will weaken a little Wednesday, as an upper-level low
continues moving across southern Canada. The feature should amplify
somewhat, as energy digs into the back side of the low. This should
help push a cold front southeastward across the Great Lakes and
toward our area. Low-level moisture should increase across the
region Wednesday, as boundary layer winds become more southwesterly
ahead of the front. Precipitable water values are expected to exceed
1.5 inches, which is between 1.5 and 2 standard deviations above
climatological means for this time of year. This, combined with
ample instability and increased forcing, should produce an increased
coverage of showers and thunderstorms by Wednesday afternoon. Prior
to any convective development, Wednesday afternoon`s heat indices
could again reach the 100-104 degree range across parts of the
Piedmont and Southside.

The front should enter our neck of the woods Wednesday evening.
From there, longer-range guidance still differs in how quickly
the front will move through our region. My current thinking is
that the front`s movement will become sluggish across our area
Thursday, then get a good push Friday as the Canadian upper-low
opens up and finally pushes the system out of our area. That
means we will likely see a more widespread convective coverage
continuing into Thursday (especially in the afternoon and
evening), before the greater coverage shifts south Friday. This
is pretty good news overall considering the ongoing dry
conditions in our forecast area. And here`s another bit of good
news - we should see a return to more reasonable temperatures
toward the end of the week (for this time of year anyway) thanks
in part to the increased cloud cover and greater coverage of
precipitation.

Surface high pressure should build across Ohio and Pennsylvania
by next Saturday. The northeasterly flow around this feature
should help bring a return to slightly drier conditions to at
least northern parts of our area. Areas farther to the south
will remain closer to the front and could continue to see a
slightly greater coverage of showers and thunderstorms. Given
the uncertainty in the location of the front at this stage of
the game, I don`t plan on straying too far from guidance at this
time.

&&

.AVIATION /23Z SATURDAY THROUGH THURSDAY/...
As of 715 PM EDT Saturday...

VFR conditions expected for the 24 hour TAF cycle, except for
patchy morning fog. The fog may drop to LIFR at LWB between
07-13Z. Winds look to be light to calm through the period.

Forecast confidence is high.


AVIATION OUTLOOK...

Daily afternoon SHRA/TSRA chances continue each day through
Tuesday, and dissipate at night. A front crosses the region
Wednesday and Thursday, bringing more widespread SHRA/TSRA and
sub-VFR conditions.

&&

.CLIMATE...
As of 715 PM EDT Saturday...

Blacksburg tied the record high for today of 92 degrees. The
previous record was set in 1936. Roanoke managed 98 degrees, one
shy of the record of 99 set in 1954.

Except for perhaps the daytime high for Blacksburg on July 16, we
currently are not forecasting record high temperatures or record
maximum low temperatures Monday, July 15, and Tuesday, July 16,
values will be close enough that some folks might be curious what
the records are. Below you will find a table that lists these values
for different locations in our region and the years those records
were set.

************* RECORDS FOR July 15 *************
+=============================================+
|  LOCATION   | RECORD HIGH  | RECORD MAX LOW |
| Blacksburg  |  99 in 1954  |   72 in 1954   |
| Bluefield   |  91 in 1951  |   72 in 1942   |
| Danville    | 104 in 1936  |   79 in 1922   |
| Lynchburg   | 101 in 1936  |   77 in 1988   |
| Roanoke     | 103 in 1936  |   74 in 1995   |
+=============================================+



************* RECORDS FOR July 16 *************
+=============================================+
|  LOCATION   | RECORD HIGH  | RECORD MAX LOW |
| Blacksburg  |  93 in 1983  |   70 in 2020   |
| Bluefield   |  96 in 1988  |   71 in 1980   |
| Danville    | 102 in 1934  |   77 in 1920   |
| Lynchburg   | 103 in 1934  |   76 in 1937   |
| Roanoke     | 100 in 1988  |   74 in 2020   |
+=============================================+

&&

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

&&

$$

SYNOPSIS...SH/WP
NEAR TERM...SH/WP
SHORT TERM...DB
LONG TERM...DB
AVIATION...SH/WP
CLIMATE...DS