789
FXUS61 KRNK 081846
AFDRNK

Area Forecast Discussion
National Weather Service Blacksburg VA
246 PM EDT Sat Jun 8 2024

.SYNOPSIS...
High pressure will promote mainly dry conditions through
tonight. A cold front tracks across the area Sunday with
scattered showers and thunderstorms mainly in the mountains. Dry
weather returns Monday. Next opportunity for showers looks like
it will hold off until the end of next week. The week as a
whole is expected to be dry.

&&

.NEAR TERM /THROUGH SUNDAY/...
As of 230 PM EDT Saturday...

Key Messages:

1. Increasing clouds tonight, but remaining dry.
2. An Autumn-like frontal passage Sunday with mountain showers
and breezy conditions.

Passage of an upper level disturbance, remnant Mesoscale
Convective Vortex (MCV), is expected tonight. Other than some
increase in cloudiness, chance for measurable rainfall is very
low. May see some virga show up on the regional radars, but
doubt anything other than a few sprinkles reach the surface.
Clouds should insulate us from radiational cooling tonight, so
not expecting temperatures to be as cool as last night. Add 5 to
10 degrees from last night`s lows and you should be in the ball
park for tonight.

In the wake of the MCV expect winds to increase from the west
northwest. Models are advertising 85H winds near 35 kts Sunday.
A surface cold front will cross the forecast area later in the
day providing some lift for a few showers and isolated
thunderstorms. Not too excited about rain chance however, the
west wind behind the MCV deterring vertical motion due to the
downslope west-northwest wind. Convective allowing models
(CAMs) are overdone on precip and will hedge toward the drier
synoptic models. Think best opportunity for showers and
thunderstorms would be across TN and into NC where wake winds
behind MCV and negative vorticity advection will have less
influence. As such will place highest pops across the NC High
Country and into the NC Piedmont.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
As of 230 PM EDT Saturday...

Key Points:

1. Slightly below normal temperatures.
2. Lingering scattered showers south and east Sunday evening.
3. Dry Monday through Tuesday other than some isolated showers
across the mountains on Monday.

A look at the 8 June 00Z NCEP Ensemble Mean 500 mb Geopotential
heights shows a slow moving upper trough expected to arrive on
Sunday night and linger through Monday. By Tuesday, the trough axis
shifts northeast to over New England while a shortwave ridge builds
over the Ohio Valley. At the surface, a cold front heads east of the
region Sunday night. For Monday, this front stalls near the coast of
the Carolinas as high pressure advances eastward from the Central
Plains states. By Tuesday, the center of the high will be closer to
our area, centered over the Ohio/Tennessee Valleys.

Output from the 8 June 00Z Ensemble Situational Awareness Table
shows 850mb temperatures Sunday night falling from around +14C to
+16C at sunset to around +10C to +12C by daybreak Monday. On Monday,
these values expand in range slightly to +10C to +13C. The values
around +10C across western sections of the region will fall into the
2.5 to 10 percentile of the 30-year climatology. The dip in
temperatures continues into Monday night with values in the +9C to
+11C range across the region. Those areas around or below +10C again
will fall within the 2.5 to 10 percentile. By Tuesday afternoon,
850mb temperatures start to inch higher and reach +12C to +14C by
the late afternoon. Precipitable Water values Sunday night are
expected to gradually decrease to the 0.75 to 1.00 inch range by
daybreak Monday. By the afternoon, the region will average about
0.75 inch. Values around or little over 0.75 inch will continue
through Tuesday night.

The above weather scenario suggests some lingering showers Sunday
evening across primarily southern and eastern parts of the region as
a cold front exits the region. By Monday, the vast majority of the
area will be dry. We will have to watch for some isolated upslope
showers across Southeast West Virginia. Additionally, with the axis
of the upper trough still over the area, we could still have some
increase mid-level lapse rates over head which may prompt some
instability aloft development during the afternoon. Any daytime
development should wane quickly after sunset. Dry and cooler than
normal conditions will take us into Tuesday and Tuesday night.

Confidence in the above weather pattern is moderate to high.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
As of 230 PM EDT Saturday...

Key Points:

1. Temperatures trending to values above normal.
2. Most locations will remain dry.
3. Better chances of showers/storms Thursday/Friday, primarily over
the mountains.

A look at the 8 June 00Z NCEP Ensemble Mean 500 mb Geopotential
heights shows the tail of a broad upper trough situated over our
area Wednesday and Thursday. On Friday, this trough gains a bit of
energy as a shortwave trough moving east along the US/Canadian
border helps to amplify it. However, the bulk of the associated
energy is still expected to remain north of our area. On Saturday,
the trough axis begins to shift northeast with building heights over
our region. At the surface, in general, high pressure will remain
over our area mid-week heading into the weekend. A backdoor cold
front will try to reach our area Friday into Saturday. Its success
is still in question.

Output from the 8 June 00Z Ensemble Situational Awareness Table
shows 850mb temperatures are expected to average +16C across the
region on Wednesday, +18C on Thursday, Friday, and Saturday. The
readings from Thursday and onward just touch the 90 to 97.5
percentile of the 30-year climatology. Precipitable Water values
will average 1.00 inch Wednesday, 1.25 inch Thursday, and 1.25 to
1.50 inch Friday and Saturday.

With the bulk of the upper level dynamics shunted well north towards
the Canadian border, our weather from mid-week through the start of
the weekend is expected to mainly dry. Temperatures will trend
milder each day, with values above normal Thursday and Friday. While
precipitation chances are not zero. They will be on the small side
across the mountains where the effects of differential heating and
orographical effects could allow for peak heating of the day isolated
showers. Confidence in the days these occur and offering a location
other than the mountains is low. However, as we move into Thursday
and Friday, the center of the ridge is expected to be slightly east
of the region. This would allow for the pooling for somewhat better
moisture into the region. A cold front may cross the region on
Saturday. This could allow for somewhat better coverage and slightly
cooler temperatures, but confidence in its passage on Saturday also
has low confidence. Our greatest confidence during this time period
is on the warming trend and most locations being dry.

&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
As of 230 PM EDT Saturday...

VFR expected through the 24 hour valid TAF, with cloud bases
generally remaining above 8kft AGL.

Winds will primarily be out of the west with surface speeds
5-10kts and a few gusts up to 20kts. Winds will generally
subside tonight, then resurface again Sunday. Sunday looks to be
a much breezier day. Models are forecasting a healthy push of
wind across the mountains Sunday with winds 30-40kts at 5kft
AGL. Expect surface gusts Sunday in the 20-30 kt range.

Above average confidence for ceiling, wind, and visibility.

EXTENDED AVIATION OUTLOOK...

VFR for most of the period. Exceptions being showers/storms
Sunday could bring sub-VFR mainly to the NC mountains, but even
low confidence on that. Mainly dry conditions expected Monday
through Thursday promoting VFR.

&&

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

&&

$$

SYNOPSIS...PM
NEAR TERM...PM
SHORT TERM...DS
LONG TERM...DS
AVIATION...PM