924
FXUS61 KRNK 071733
AFDRNK

Area Forecast Discussion
National Weather Service Blacksburg VA
133 PM EDT Sun Jul 7 2024

.SYNOPSIS...
A front will waver across central Virginia and North Carolina
through the week. The chance of showers and thunderstorms will
continue each day. Unseasonably warm and humid weather will also
remain over the region.

&&

.NEAR TERM /THROUGH MONDAY/...
As of 121 PM EDT Sunday...

Key message:

    - Highest confidence for thunderstorms across North Carolina and
      southern Virginia this afternoon and evening
    - Scattered showers/storm across most of the area Monday


Showers continue in an widely scattered fashion across the NC
piedmont into southside VA. The latest HRRR has a pretty good
handle but still not enough coverage. PWATS this morning have
risen to 2.12 at GSO and 1.36 at RNK.

There is a bubble of moisture increasing from the southeast per
loop of MSAS, with inverted trough across the upper TN Valley,
with actual front stretching from the Tidewater of VA west-
southwest through central NC. This configuration may allow for a
little more lift swinging into southern VA this afternoon, with
also some low level convergence along the southern Blue Ridge
into the upper TN valley where isolated storms are possible, so
a little more coverage than Saturday but still ranging from
isolated/widely scattered from Bluefield-Blacksburg-Farmville,
to better coverage south of the VA/NC border, and moreso in the
NC mountains. With pwats this high, will have to watch for
localized flooding issues as thunderstorms with be proficient
rain makers and slow movers.

Front stay stalled in the vicinity through Monday and southwest
flow aloft plus any embedded weak waves combined with low level
moisture convergence will keep the threat of showers/storms
around, however, most will stay dry in terms of rain but the
humidity stays elevated especially along/east of the Blue Ridge.

Any storms will be working with high moisture content Monday as
well, so localized flooding is possible, especially if it rains
where it does this afternoon/evening with urban areas and steep
terrain more prone. Still isolated so not anything close for a
watch.

Lows tonight stay elevated in the mid to upper 60s west of the
Blue Ridge to lower 70s east. Fog could get locally dense in the
mountain valleys and where it rains this afternoon/evening if
enough clearing takes place.

Highs Monday will be dependent on cloud cover and should more
clouds than sun, but enough to send temperatures into the 80s in
the mountains to lower 90s Piedmont.

Forecast confidence is moderate on rainfall coverage and temps.


&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
As of 1255 PM EDT Tuesday...

Key Messages:

1. Heat index values peaking between 100 and 105 Tuesday afternoon
east of the Blue Ridge.

2. Near record to record high minimum temperatures for some
locations Wednesday morning.

The deterministic medium range models and ensembles are in good
agreement that the persistent southeast U.S. upper level ridge will
amplify over our area Tuesday resulting in a return to well above
normal temperatures and oppressive heat index values, especially
east of the Blue Ridge where these values will likely reach close to
or over advisory (105 degrees) criteria. Did lower the NBM forecast
high for ROA by a degree as it was an outlier compared to other
members of the NBM ensembles.

The upper level ridge flattens slightly on Wednesday as an upper
level trof, which appears to absorb the remains of Beryl, moves into
the Great Lakes region by Wednesday evening. This will bring down
temperatures a few degrees, but still well above normal with heat
index values still expected to be between 100 and 105 east of the
Blue Ridge.  NBM low temperature forecasts (which were generally
followed), suggest near record to record high minimum temperatures
Wednesday morning.

The GEFS shows PWAT anomalies slightly above 1 standard
deviation above normal on Tuesday, but increases to 1.5 to 2
standard deviations above normal Wednesday. Plus, forecast
soundings show higher CAPES on Wednesday with slightly stronger
0-6km bulk shear values. As a result, lowered POPs for Tuesday
(with scattered storms mainly in the mountains) and went below
NBM guidance, while keeping high POPs, more closely aligned to
the NBM, in place for Wednesday. areas of heavy rain and
localized flash flooding is possible, especially if storms
form/move over urban and poor drainage areas.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
As of 130 PM EDT Sunday...

Key Messages:

1. Localized flash flooding possible late this week.

The WPC Cluster Analysis output shows increasing uncertainty with
the amplitude and timing of an upper level trof moving across the
Great Lakes and potentially into the northeast U.S. this weekend.
This will be critical to the location of a surface boundary late
this week in or close to our forecast area.  Considering there will
be an upper level low in the western Atlantic weakening and lifting
west, then north, across the Mid-Atlantic coast on Friday, this
suggests the surface boundary will have a difficult time advancing
eastward and remain in, or very close to our forecast area.

This will result in a good chance for showers and storms Thursday,
Friday and potentially Saturday, with the ECMWF Extreme Forecast
Index highlighting Friday as the day with the best chance for heavy
rain and potential flash flooding. The NAEFS keeps PWAT values 1-2
standard deviations above normal late this week which provides
higher confidence that locally heavy rain will be possible somewhere
in the region. Will continue to highlight the threat for locally
heavy rain in the HWO.

With additional cloud cover expected late this week, went a couple
of degrees below the NBM forecast highs, until Sunday, when the
upper level trof begins to lift and the GEFS indicating 850mb temps
returning to 1-2 standard deviations above normal.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
As of 125 PM EDT Sunday...

Scattered to broken cumulus with some TCU/CB possible this
afternoon. Best chance of TCU/CB will be along/south of a HLX-
DAN line. As such have some showers around DAN this afternoon
with VCTS as well. Cannot rule out some development toward
BCB/BLF but low confidence.

Mainly VFR outside any showers/storms with cigs in the 4-8kft
range.

Front will remain in place through Monday across the Piedmont.
Anticipate some fog/low clouds at time late tonight, mainly
BLF/LWB/BCB but could have some at DAN as well. Vsbys could drop
as low as 1/2sm at LWB.

Ceilings/vsby should rise to VFR after 13-14z. Widely scattered
storm set up for Monday afternoon after this taf period.


Low confidence on cigs/vsbys tonight with average on storms.
High confidence in mainly VFR outside of storms/fog.


AVIATION OUTLOOK...

Little change in the weather pattern and location of the front
is expected through the rest of the week. This will result in a
daily threat of thunderstorms, mainly in the afternoon and
evening.

Prevailing conditions will be VFR. The exception will be brief
periods of IFR/MVFR with the thunderstorms and also with
overnight fog.

&&

.CLIMATE...
As of 520 AM EDT Sunday...

Records for the warmest minimum temperatures may be set at
Blacksburg on Monday and Tuesday.

Tuesday looks to be the warmest day of the week so those records
have been listed here.


July 7th
Site  MaxT Year  MinT Year  LoMax Year  HiMin Year
KBLF    93 2012    44 1951     65 1967     73 1998
KDAN   104 2010    55 1979     76 1961     78 1921
KLYH   100 2012    52 2001     72 2005     75 1977
KROA   102 2012    48 1983     74 2005     78 1977
KRNK    94 2010    41 1972     67 1967     67 2022

July 8th
Site  MaxT Year  MinT Year  LoMax Year  HiMin Year
KBLF    93 2012    45 1951     70 1947     71 1977
KDAN   103 2012    54 1979     74 1949     78 1930
KLYH   101 2012    53 1983     68 1918     75 2022
KROA   102 2012    50 1979     74 1949     77 2012
KRNK    96 1988    42 1896     67 1896     70 1941

July 9th
Site  MaxT Year  MinT Year  LoMax Year  HiMin Year
KBLF    92 2007    42 1918     63 1979     75 1994
KDAN   103 1977    52 2018     69 1950     76 1987
KLYH   102 1936    53 2018     66 1927     74 1992
KROA   101 1936    48 1918     68 1969     77 1992
KRNK    97 1988    42 1961     67 1927     67 1939

&&

.EQUIPMENT...
As of 520 AM EDT Sunday...

KFCX Radar is degraded...Horizontal Low Noise Amplifier is INOP,
damaged by thunderstorm.  Please use data with caution.
High reflectivity above 40 dbz appears OK, but the radar is unable
to detect and lower reflectivity. A Low Noise Amplifier has
been emergency ordered.

&&

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

&&

$$

SYNOPSIS...AMS/WP
NEAR TERM...WP
SHORT TERM...PH
LONG TERM...PH
AVIATION...AMS/WP
CLIMATE...AMS
EQUIPMENT...PM