336
FXUS61 KRNK 151108
AFDRNK

Area Forecast Discussion
National Weather Service Blacksburg VA
708 AM EDT Wed May 15 2024

.SYNOPSIS...
Slow moving low pressure system will bring another day of
showers and thunderstorms to the area, before exiting to the
east Thursday morning. A lingering trough will keep a few
showers around Thursday before another storm system works in
from the Ohio and Tennessee Valleys late Friday, with another
round of showers and storms continuing into Saturday.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 330 AM EDT Wednesday...

Key Messages:

1) Weather unsettled again today with marginal risk of severe
thunderstorms and localized flooding.

Small area of showers/few thunderstorms across southwest VA and NW
NC early this morning is associated with an upper vort tracking
across the upper TN Valley. Following close to the latest HRRR shows
this activity waning through dawn as it moves into more stable air
across the New River Valley and southeast WV, but showers likely to
remain, but thunder chances lower.

Models have some minor differences on timing/strength of upper
impulses but in general the flavor is for the upper trough across KY
into the TN Valley this morning to slide slowly east and weaken by
evening. This will keep our area in southwest flow and showers
becoming more numerous as the day progresses. At the surface two to
three areas of low pressure existed with the main one over the lower
Ohio Valley, with another out toward the VA Tidewater. Warm front
was still south of us with a weakening occlude front over the TN
Valley. Today, will see the warm front lift north into central VA by
dawn, then off the coast by mid afternoon while the main cold front
pushes across the southern Appalachians into eastern NC during the
afternoon. With several mesoscale lows, and increased instability
despite the cloud cover, a few storms could become strong to severe.
Keeping the main threat along/south of the VA/NC border closer the
the main low and cold front. Damaging winds and hail to 1" diameter
may occur after midday today, with multicellular storms. Cannot rule
out a few supercells but environment favors these more across
central NC.

Another issue will be high moisture content and flooding potential.
Yesterday saw 2-4+" of rain across portions of southside VA into the
NC piedmont. Today, indication suggest more of a flooding threat
along/west of the Blue Ridge, but will also have to monitor
convection over southside VA into NC. At the moment, per evolution
on convective allowing models appears any flooding would be
localized and not enough to pinpoint any one location for a flood
watch. Will monitor as the day wears on.

Instability starts to wane this evening but lingering showers
possible through the overnight as a weak surface trough remains
behind the front across NW NC into southern VA. Fog may become an
issue later tonight if we clear out but confidence is low, so
keeping just patchy fog in after midnight over the
mountains/foothills.

Temperatures should be warmer today with warm front lifting north
but still slightly below normal for mid May with mid 60s to around
70 for most, with lower to mid 70s southside VA into NC
foothills/piedmont. Stays mild tonight as airmass doesn`t change
much behind the departing low with lows in the mid to upper 50s for
most of the area.

Forecast confidence is high on rain chances, temperatures and sky
cover and lower on severe/flooding threat.

&&

.SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/...
As of 230 AM EDT Wednesday...

Key Messages:

1. Showers and storms Friday continue into Saturday.
2. Some clearing with a break in the rain Thursday.

An upper level trough axis will be situated to the east of the area
by Thursday morning, with a surface low moving offshore of the
Delmarva Peninsula. Weak ridging aloft is expected to build into the
area, and high pressure at the surface will help to reduce
precipitation chances through Thursday. This break will be
short lived, as another low pressure system and upper trough
track eastward into the Ohio and Tennessee Valleys by the end of
the work week. This system will bring the next round of rain
with the potential for some thunderstorms Friday afternoon and
through Saturday, first for southwest VA and northwest NC, then
expanding to the rest of the forecast area by late Friday. Above
normal PWATs, at or exceeding the 90th percentile, will mean
heavy rainfall is possible with this system. Given the recent
rainfall earlier in the week, there is the possibility for
localized flooding. Mesoscale details are still uncertain at
this time in the forecast period, but thinking instability will
be limited with abundant cloud cover, although shear may be
enough to support some bit of organization to any convection.
However, overall impression is a less favorable environment for
severe thunderstorms for Friday and Saturday.

Temperatures will be in the 70s for most for Thursday and Friday,
but a few degrees cooler on Saturday following the passage of the
cold front, in the mid to upper 60s in the west, and low to mid 70s
in the east. Lows will be in the 50s and 60s each night.

&&

.LONG TERM /SUNDAY THROUGH TUESDAY/...
As of 230 AM EDT Wednesday...

Key Messages:

1. Decreasing coverage of showers on Sunday.
2. Drier for Monday and Tuesday.

The long term forecast period looks to be drier than the short term
period. The 500mb trough will cross the area on Sunday, with ridging
building in behind. Rain will linger in the area through at least
Sunday morning, depending on the timing of the departure of the cold
front. Coverage of precipitation will decrease through Sunday,
becoming limited to the western slopes as winds turn northwesterly
behind the front. High pressure shifts back over the eastern US late
in the weekend and beginning of the work week, further reducing
coverage of precipitation, so Monday and Tuesday look to be dry at
this time. Increasing 500mb heights suggest a warming trend for the
beginning of the week, temperatures reaching normal to slightly
above normal for this time of year. Another low pressure system
develops over the central US by the middle of the work week, and
will progress northeastward towards the Midwest and Great Lakes. Any
impacts from this system to the forecast area look to be beyond the
forecast period at this time.

&&

.AVIATION /11Z WEDNESDAY THROUGH SUNDAY/...
As of 706 AM EDT WEDNESDAY...

Weather will dictate cigs/vsbys but confidence is high on sub-
VFR for most of this taf period. There will be some fluctuations
between VFR to IFR this morning, but overall a poor flying day
as showers/scattered storms take shape after 17z, then should
taper off toward late evening with low cigs/fog becoming an
issue.

EXTENDED AVIATION OUTLOOK...

Thursday: VFR flight categories expected, after low clouds/fog
lift Thu morning, some sub-VFR with showers possible.

Friday: Deteriorating conditions. Flight restrictions possible
by afternoon due to low CIGs with an increasing coverage of
SHRA/TSRA.

Friday night and Saturday: Flight restrictions expected due to
low CIGs/VSBYs in SHRA/TSRA.

Sunday: Some restrictions possible, especially early, with a
decreasing coverage of SHRA/TSRA.

&&

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

&&

$$

SYNOPSIS...WP
NEAR TERM...WP
SHORT TERM...AS
LONG TERM...AS
AVIATION...DB/WP