108
FXUS61 KRNK 102333
AFDRNK

Area Forecast Discussion
National Weather Service Blacksburg VA
733 PM EDT Mon Jun 10 2024

.SYNOPSIS...
Isolated showers then cooler weather is expected tonight. Dry
weather prevails through the work week. Temperatures trend
warmer with 90s possible for highs in some locations Wednesday
through the weekend.

&&

.NEAR TERM /THROUGH TUESDAY/...
As of 730 PM EDT Monday...

Key Messages:

1) A few showers and possibly an isolated thunderstorm this
evening.

2) Dry weather Tuesday.

Isolated showers were west of the Blue Ridge in association with
a short wave tracking into eastern West Virginia. A majority of
the showers will dissipate before 9PM and the rest will erode
before midnight as the vorticity passes to the north of the
region. Have adjusted the probability of precipitation for the
latest radar trends and added a bit more cloud cover in the
mountains overnight with the expected upslope wind. No changes
to temperatures at this time.


Previous discussion
As of 130 PM EDT Monday...

Troughing still remains in the eastern United States with
multiple shortwaves rotating through the longwave pattern. One
shortwave crosses the area this afternoon and will reinforce
drier and slightly cooler weather for tonight and tomorrow.

Widespread cumulus has developed across the area this afternoon,
but so far shower/storm activity has been kept to a minimum.
Still may see some showers and possibly an isolated
thunderstorm as a weak surface front associated with the
shortwave passes later this afternoon and into the evening.

Limited surface based instability, but some elevated instability
and steep lapse rates may drive the isolated convection as
better forcing passes through in the next few hours.

Dry tonight after the front passes with partly cloud skies. Some
upslope cloudiness is possible through the morning hours for the
western mountains. Some morning valley fog possible.

High pressure builds in from the west Tuesday and mostly sunny
and dry conditions are expected.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
As of 100 PM EDT Monday...

Key Points:

1. Slightly below normal temperatures on Wednesday.
2. Slightly above normal temperatures on Thursday.
3. No precipitation expected.

A look at the 10 June 00Z NCEP Ensemble Mean 500 mb Geopotential
heights shows the axis of a shortwave trough east and northeast of
the region with weak ridging arriving Tuesday night. During
Wednesday, the pattern over the region transitions to nearly a zonal
flow, but does maintain a bit of a wnw-ese orientation. A deep low
will be positioned just west of Greenland with a trough a trough
extending to along the Ontario/Quebec border. On Thursday, the
Canadian trough amplifies a bit into the Great Lakes region. Flow
across our region maintains a wnw-ese orientation. By the end of
Thursday night, the trough is expected to be located from southwest
Quebec to the Upper Tennesse Valley. At the surface, a generally sw-
ne oriented ridge of high pressure is expected to over the region
Wednesday into Thursday. Its position may be slightly farther south
on Thursday as compared to Wednesday, being displaced slightly by an
approaching cold front across the Upper Mississippi River Valley.

Output from the 10 June 00Z Ensemble Situational Awareness Table
shows 850mb temperatures Tuesday night around +12C across the
region. By Wednesday values are expected to average +14C to +16C. On
Thursday those numbers increase a bit more to +16C to +18C. The
western portion of the area will be within the upper end of this
range, and also just touch the 90 to 97.5 percentile of the 30-year
climatology. Precipitable Water values Tuesday night are expected to
range from a little bit less than 0.75 inches across the far western
parts of the area to a little shy of 1.00 inch over eastern section.
Locations within the sub-0.75 inch values will experience readings
within the 2.5 to 10 percentile of the 30-year climatology. On
Wednesday, readings increase to around 0.75 inch to a little over
1.00 inch. By Thursday, expect readings around or little over 1.00
inch for the entire area.

The above weather scenario points to a forecast with little to no
probability of precipitation. Temperatures will be around or slightly
cooler than normal on Wednesday and a few degrees above normal for
Thursday.

Confidence in the above forecast is high.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
As of 100 PM EDT Monday...

Key Points:

1. Above normal temperatures through the period, especially Friday
and Monday.
2. Primarily dry cold front passage on Friday.
3. Return of isolated/scattered mountain showers/storms by Sunday/Monday.

A look at the 10 June 00Z NCEP Ensemble Mean 500 mb Geopotential
heights shows that by Friday evening, the trough is expected to be
located from southwest Quebec to the Upper Tennesse Valley. This
feature crosses our area late Friday night into Saturday, and by
Saturday evening is centered over New England. Shortwave ridging
takes place over the mid to upper Mississippi Valley. On Sunday,
the ridge strengthens and shifts east and by the evening hours
extends from the area of TN/GA/NC north to the Ontario/Quebec
border. On Monday, the ridge continues to build with the axis
showing no longitudinal movement, but with increasing heights across
our area. At the surface, on Friday a cold front is expected to
cross our region. By Saturday, high pressure returns to the area.
Its center is expected to shift into the western Atlantic by
Sunday/Monday, with its associated ridge axis extending west into
our region.

Output from the 10 June 00Z Ensemble Situational Awareness Table
shows 850mb temperatures on Friday are expected to range from +18C
to +20C across the area. This places the entire region within the 90
to 97.5 percentile of the 30-year climatology. Saturday values will
be slightly lower, ranging from +17C to +19C. Only a small change is
expected Sunday with readings of +16C to +18C. We see another small
tick upward on Monday with readings of +19C to +20C. The top end of
this range is across western part of the region, within the 90 to
97.5 percentile of the 30-year climatology. On Friday, Precipitable
Water values will average 1.25 inch across the region. On Saturday,
expect a fairly tight nw-se gradient with readings over SE WV around
0.75 inch with South Virginia seeing number just shy of 1.25 inch.
On Sunday, values will range from 1.00 to 1.25 across the area, and
a little over 1.25 for Monday.

For this portion of the forecast, the latest model trends suggest
little to no precipitation is expected with the passage of the cold
front on Friday. If there is any, it would be in the form of
isolated showers, an perhaps a rumble or two of thunder, over parts
of Southeast West Virginia. Post cold front, as the center of an
area of high pressure crosses our region and progresses eastward
into the western Atlantic, anti-cyclonic flow around the high will
progressively mean better moisture flux off the Atlantic and into
our region. While are not talking widespread rain, we are
recognizing that with this increased moisture, and with a weakening
cap as the high shifts east, daytime heating combined with
orographic influences will allow for the potential for some
afternoon showers/storms by Sunday/Monday. Temperatures will average
above normal for this time of year during this portion of the
forecasts, especially on Friday and Monday.

Confidence in this section of the forecast is moderate.

&&

.AVIATION /23Z MONDAY THROUGH SATURDAY/...
As of 725 PM EDT Monday...

Isolated showers west of the Blue Ridge will gradually dissipate
this evening, with dry weather expected after midnight/04Z. A
cold front was crossing west to east over the central
Appalachians this evening, turning the wind to the northwest and
north. MVFR ceilings will spread into the mountains late
tonight behind this front. MVFR to LIFR river valley fog is also
expected, mainly between 06Z/2AM and 12Z/8AM. The probability
for fog is highest at KLWB where is rained Monday so have
maintained that in the TAF overnight. KBLF and KBCB may also
have fog, but confidence at these airports is lower.

High pressure builds across the region Tuesday. VFR conditions
are expected once the shallow fog burns off in the morning. It
may take until late morning for ceilings to lift to VFR and
clouds to become scattered over the mountains. In general,
Bufkit forecast soundings were showing the potential for
scattered stratocumulus in the 2 to 4Kft AGL range in the
mountains and foothills.

Average confidence for ceiling, visibility, and wind.

EXTENDED AVIATION OUTLOOK...

VFR anticipated through the upcoming week. Mainly dry conditions
expected through Saturday.

&&

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

&&

$$

SYNOPSIS...BMG
NEAR TERM...AMS/BMG
SHORT TERM...DS
LONG TERM...DS
AVIATION...AMS/BMG