277
FXUS61 KRNK 080732
AFDRNK

Area Forecast Discussion
National Weather Service Blacksburg VA
332 AM EDT Mon Jul 8 2024

.SYNOPSIS...
Little change in the weather pattern is expected through the end of
the week. Scattered thunderstorms each afternoon and evening will
have the potential to produce very heavy rain. Tuesday and Wednesday
will be the hottest days of the week, with the humid conditions and
unseasonably warm temperatures continuing into the weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 300 AM EDT Monday...

Key messages:

    - Highest confidence for thunderstorms and excessive
      rainfall in the North Carolina mountains and foothills

Overall pattern keeps southeast surface and low level wind today,
reacting convergence along and just east of the southern Blue Ridge.
This may result in a similar training pattern as seen on Sunday
with storms forming and moving northeast, then forming again
near the original location were the convergence is maximized.

The Ensemble situational Awareness tables showed the highest
concentration of well above normal precipitable water values in the
North Carolina foothills today. Rainfall will again be in the
2-4 inches/per range. This potential for excessive rainfall will
be highlighted in the Hazardous Weather Outlook.

Bufkit forecast soundings showed a layer of warmer air between 850
and 800 MB. It may take until 19z/3PM for to reach the convective
temperature and overcome this cap. Broken layer of mid and high
clouds will somewhat limit heating this morning, but starting out in
the mid 60s to mid 70s, so not a stretch to get back into the 80s
and 90s. Muggy surface dew points in the lower 60s to lower 70s, so
no major changes to forecast lows for tonight.

&&

.SHORT TERM /TUESDAY 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 /08Z MONDAY THROUGH FRIDAY/...
As of 325 AM EDT Monday...

Overall pattern keeps southeast surface and low level wind today,
reacting convergence along and just east of the southern Blue Ridge.
This may result in a similar training pattern as seen on Sunday
with storms forming and moving northeast, then forming again
near the original location were the convergence is maximized. A
majority of the thunderstorms this afternoon and evening will
remain south of KBLF and KBCB.

Bufkit forecast soundings showed a layer of warmer air between
850 and 800 MB. It may take until 19z/3PM for to reach the
convective temperature and overcome this cap. Broken layer of
mid and high clouds this morning was keeping IFR/LIFR fog and
stratus patchy. Satellite showing more gaps in the high clouds
west of the Blue Ridge. This favors MVFR to LIFR fog at KLWB and
KBCB before 12Z/8AM. Any stratus and fog should dissipate by
13-14z.

Average confidence on ceiling and wind.
Below average confidence on timing and extent of thunderstorm
coverage today.

AVIATION OUTLOOK...

Little change in the weather pattern 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 Monday...

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 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 820 PM EDT Sunday...

KFCX Radar is degraded...Horizontal Low Noise Amplifier is INOP,
damaged by thunderstorm. Data from the radar has been
compromised. Please use data with caution. A replacement
amplifier has been emergency ordered. Estimated back in service
time is 6PM Tuesday.

&&

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

&&

$$

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