547
FXUS61 KRNK 131725
AFDRNK

Area Forecast Discussion
National Weather Service Blacksburg VA
125 PM EDT Mon May 13 2024

.SYNOPSIS...
A low pressure system will cross the Mid Atlantic during
Tuesday and Wednesday to bring showers and thunderstorms. Weak
high pressure should provide drier air for Thursday, but
another low pressure system will bring more rain for the end of
this week.

&&

.NEAR TERM /THROUGH TUESDAY/...
As of 125 PM EDT Monday...

Key Messages:

1) Confidence is high for rain arriving later tonight and
persisting through Tuesday.

2) Thunderstorms will be possible by Tuesday afternoon.

Some dense cirrus has been spreading across locations south of
Route 460 today as a low pressure system approaches the central
Mississippi River Valley. The 12Z RNK sounding was still dry
with only a precipitable water value of 0.38 inches, so any rain
chances are delayed until later tonight. A southerly breeze at
the surface combined with an upper level ridge building overhead
should boost temperatures into the 60s and 70s this afternoon.

The low pressure system will push a warm front towards the
southern Appalachian Mountains tonight, which will provide
increasing chances of rain. Instability is zero overnight as
depicted in the high-resolution models, so no thunderstorms are
expected until later on Tuesday. The highest chances of rain
were placed along and east of the Blue Ridge in reasonable
agreement with the models. With cloud cover and warm advection
taking place tonight, low temperatures will only fall into the
50s for most locations, which is about fifteen degrees higher
than the temperatures observed earlier this morning.

Tuesday morning will start cloudy with rain spreading across
the Mid Atlantic. Lift from the warm front may spark enough
instability aloft by Tuesday afternoon to introduce chances of
thunderstorms. While there could be some heavier downpours in
these storms, antecedent conditions are still rather dry from
the past week, so the flooding threat is low. The highest odds
of storms are located either in the mountains west of the Blue
Ridge or across northwest North Carolina and southside Virginia.
Temperatures will only reach the 60s for highs due to the
abundant cloud cover from a moist southeast flow.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
As of 245 AM EDT Monday...

Key Messages:

1. Dry weather returns Thursday.
2. Near normal temperatures through midweek.

Shower and storm chances continue into Wednesday, as moisture
wraps around the low as it tracks through the Mid Atlantic. By
early Thursday morning, 500mb ridging builds back into the area,
in response to another trough deepening over the Rockies and
western US. A drier airmass fills into the area behind the
front, reducing shower and storm coverage for Thursday.

Temperatures will generally be near normal for this forecast
period, cloud cover keeping overnight lows on the mild side,
in the 50s and 60s. High temperatures will gradually warm
through the period, with Thursday looking to be the warmest day,
highs near 80 in the Piedmont, and in the low to mid 70s in the
west.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
As of 230 AM EDT Monday...

Key Messages:

1. Showers and storms possible again Friday, lingering into the
weekend.
2. Near to slightly above normal temperatures.

Mid level ridging will slide east of the area through Friday
with flow aloft turning more southwesterly. Another surface
low pressure will approach the area from the west, bringing the
next chance for widespread showers and thunderstorms. As noted
in the previous discussion regarding this system, deterministic
models continue to show differences in timing and placement of
the heaviest precipitation from this system, with some
suggesting greater precipitation to the north and to the south
of area, and others showing a broad axis of heavy rain across
much of the eastern US, although better agreement in showers
reaching the area by at least Friday afternoon and continuing
into Saturday. That being said, confidence is lower in the
forecast for the end of the workweek. Thinking the potential for
storms Friday is lower than the middle of the week system,
since the upper trough is not quite as strong, the base of the
ridge farther north of the area compared to the Tuesday system.

Upper ridging and surface high pressure move back into the
eastern US by Sunday as the low moves off the coast, decreasing
coverage of any lingering precipitation.

Sunday looks to be the warmest day of this forecast period with
high pressure overhead. Cloud cover and rain will keep Friday
and Saturday cooler, but generally temperatures will be near
normal.

&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
As of 125 PM EDT Monday...

VFR conditions are expected at all terminals through the
remainder of today with a south breeze. However, a low pressure
system will approach from the southwest tonight, which is
responsible for the cirrus spreading across the Mid Atlantic
today. Ceilings should lower to MVFR after midnight tonight and
fall further to IFR by early Tuesday morning as rain becomes
more widespread. Patchy fog and a chance of LIFR ceilings may
also accompany the rain in the morning.

Ceilings will not rise much during Tuesday due to a moist
southeast flow. Heavier rainfall rates are possible for LYH and
DAN as the warm front from this low pressure system lifts
northeastward. Chances of thunderstorms will gradually increase
by Tuesday afternoon due to increasing instability aloft, but
most terminals are expected to remain cloudy with poor flying
conditions throughout the day.

Extended Aviation Outlook...

Poor flying conditions will continue through Tuesday night into
Wednesday as a cold front approaches from the west. Scattered
showers and thunderstorms should continue through Wednesday
evening but start to fade by Wednesday night as the cold front
exits. VFR conditions should return for most terminals by
Thursday due to weak high pressure passing to the north.
However, another low pressure system could arrive during Friday
afternoon into Saturday to bring low ceilings and scattered
showers and thunderstorms.

&&

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

&&

$$

SYNOPSIS...PW
NEAR TERM...PW
SHORT TERM...AS
LONG TERM...AS
AVIATION...PW