337
FXUS61 KRNK 020240
AFDRNK

Area Forecast Discussion
National Weather Service Blacksburg VA
1040 PM EDT Sat Jun 1 2024

.SYNOPSIS...
A low pressure system in the Mid Mississippi Valley will track east
tonight and Sunday bringing showers and thunderstorms to the
region. Daily showers and thunderstorms continue for the region
through Thursday, before drier weather returns for the end of
the week. After Sunday, temperatures will be near to slightly
above normal for much of the week.

&&

.NEAR TERM /NOW THROUGH SUNDAY/...
Issued at 1040 PM EDT Sat Jun 01 2024

Precipitable water values are hovering around 0.5 inch across
the region late this evening. These values should increase
overnight (especially after midnight-2 a.m.), as boundary layer
winds veer slightly more southwestward and increase in speed.
This should result in a pretty quick moistening of the lower
troposphere through the pre-dawn hours.

That said, I`ve decided to leave well enough alone with the PoPs
overnight. While it still looks like the greatest odds of seeing
precipitation reach the ground will be after sunrise, it`s not
outside of the realm of possibility a few spotty light rain
showers could be seen overnight. I made a few tweaks here and
there to the other sensible weather elements, but the overall
forecast appears to be in good shape for now.

Issued at 728 PM EDT Sat Jun 01 2024
Ongoing forecast appears to be on target early this evening.
Mostly high-level clouds continue to increase from the west,
thanks in part to a shortwave trough moving across the Ohio and
Tennessee Valleys. A mosaic of radars to our west shows at least
a scattered coverage of showers and thunderstorms associated
with the disturbance, but the big question (in my mind at least)
is when/if the precipitation will arrive in our area.

CAMs remain consistent in bringing some of this precipitation into
our western counties overnight a couple of hours before sunrise.
However, the lower part of our atmosphere remains dry, which isn`t
too good if you`re a cloud that produces rain that wants to reach
the surface. As the 850hPa flow strengthens, the boundary layer will
moisten over the next 24 hours. I`m just not sure it`ll be much
before Sunday morning. For now, I`ll let the ongoing forecast ride
and wait-and-see what this evening`s sounding shows.

As of 130 PM EDT Saturday...

Key message:

   - Showers and isolated thunderstorms return for late tonight into
     Sunday

A short wave and the associated showers and thunderstorms over the
Tennessee Valley was spreading high clouds into the area today.
Cloud cover will continue to increase overnight. Will be using a
blend of the 3km NAM and RAP guidance for the leading edge of
precipitation tonight.

Low level wind will be out of the south-southwest tonight and Sunday
with increasing wind speeds over the mountains by early Sunday
morning. Precipitable water values this morning were in the 0.25 to
0.50 inch range. Expecting a quick return of deeper moisture with
precipitable water from 1.0 to 1.5 inches by the end of the day
Sunday. Air mass will be saturating from the top down and this may
delay the onset of the precipitation compared to the timing
suggested in the models. Confidence high that any rainfall will
remain west of Virginia and North Carolina through 03Z/11PM.

All the cloud cover tonight and surface dew points rising into the
upper 40s to mid 50s will result in warmer minimum temperatures than
the past couple of mornings. Similarly, the clouds and precipitation
on Sunday morning will prevent a large rise in temperatures. Models
were not showing much clearing behind the short wave on Sunday.
Maybe enough in the mountains to allow for enough heating and
instability to support the development of thunderstorms in the late
afternoon and evening.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
As of 120 PM EDT Saturday...

Key Message:

1. Chances for mainly daily afternoon showers and storms.

We start out with a departing upper shortwave and some brief ridging
to the area for Sunday night into Monday so there should be a
decrease in shower/storm activity during the period with a low end
chance for some diurnally driven development Monday afternoon. For
Tuesday into Tuesday night, there doesn`t look to be any key feature
to weigh into for influencing the area as there could either be
split flow aloft, continued weak ridging, or possible moisture
advection with a weak wave approaching from the west. Will keep it
general chance for convection given the various
solutions/uncertainty.

Max temps Monday should be a bit above climo norms, then warmer for
Tuesday especially if there is any continued weak ridging.

Forecast confidence is medium.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
As of 120 PM EDT Saturday...

Key Messages:

1. More widespread shower/storm chances for Wednesday and possibly
Thursday.

2. Drier conditions or less convective activity finally could return
Friday.

For Wednesday, stronger enhanced moisture advection and an elongated
front looks to phase with an amplifying upper broad trough mainly NW
of the area near the upper plains and Great Lakes, and a weaker
shortwave piece of energy that could push across the TN Valley/Mid-
Atlantic. This should be our next greater chance for more widespread
or organized showers and storms. A secondary weaker front could
traverse into the area on the heels of the Wednesday system along
the transitioning NW flow in the southern extent of a possible very
broad and deep closed upper low. Of all days, Friday could be the
driest if we get a push of reduced humidity behind that second
fropa. Uncertainty exists thereafter with the evolution of the
upper low and what waves may come across its south.

Max temps progged to be near to above normal during period.

Forecast confidence is medium.

&&

.AVIATION /03Z SUNDAY THROUGH THURSDAY/...
Issued at 728 PM EDT Sat Jun 01 2024

A shortwave trough traversing the OH and TN Valleys early this
evening continues bringing a mostly Cs deck into the region from the
W. Expect the clouds to thicken and gradually lower overnight, as a
strengthening boundary layer flow continues to moisten the lower
part of the atmosphere. Despite the expected (eventual) OVC skies,
CIGs should remain VFR across the region through 02/1800 UTC.
Probabilistic guidance suggests that there could be some CIGs,
possibly into MVFR territory, after 02/2100 UTC. And while there may
be some BINOVC Sunday after passage of the shortwave trough, I don`t
think it`ll be much.

Radar mosaics to our W continue showing at least a SCTD coverage of
SHRA/TSRA associated with this shortwave. Question is how much of
this will reach our area before 02/1200 UTC. Bottom line is that
a lot of dry air still remains across our region as of this
writing. Right now, I will refrain from mentioning -SHRA in the
evening TAFs and continue the use of VCSH after 02/1200 UTC
given my overall confidence of measurable RA being seen at any
one specific terminal.

Winds should mostly be L/V from the S tonight, then increase to 5-10
kts. Sunday. Some higher gusts may be seen, especially in the usual
spots.

OUTLOOK SUNDAY NIGHT THROUGH THURSDAY...

Sunday night-Tuesday night: Mostly VFR, but ISOLD/SCTD SHRA/TSRA
could result in periodic restrictions through the period. Some BR is
also possible, especially in valley locations.

Wednesday-Thursday: Greater likelihood of restrictions/MVFR (or
lower) flight categories due to SHRA/TSRA.

&&

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

&&

$$

SYNOPSIS...AMS/DB
NEAR TERM...AMS/DB
SHORT TERM...AB
LONG TERM...AB
AVIATION...DB