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803
FXUS61 KRNK 040903
AFDRNK

Area Forecast Discussion
National Weather Service Blacksburg VA
503 AM EDT Sat May 4 2024

.SYNOPSIS...
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An upper level trough of low pressure will move across the Mid-
Atlantic Region this weekend resulting in mostly cloudy skies,
widespread showers, and a few thunderstorms. Rainfall amounts
will be highly variable, ranging from a quarter of an inch, to
as much as one inch. Temperatures will be lower today compared
to Friday, winds from an easterly direction.
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&&

.NEAR TERM /THROUGH TONIGHT/...
As of 230 AM EDT Saturday...

Key Messages:

1. Cool easterly wind today. Below normal high temperatures.

2. Widespread light to moderate showers through tonight with
potential for 0.25 to 1.00 of rain. Slight chance thunderstorms.


Cloudy skies observed across the entire forecast area this
morning along with patchy light rain and rain showers. This will
generally be the theme through tonight as lift associated with
an upper level trough persists across the region. Daytime
heating may provide enough CAPE to produce a few thunderstorms,
but not expecting anything severe per cool easterly wind flow
within the boundary layer. Models are hit and miss on the
heavier QPF, advertising a large deviation in rainfall amounts,
the SREF Plumes for many of our climate stations ranging from a
quarter of an inch to as much as 1.5 inches through 8AM Sunday.
The spread in the model data reflects the showery nature of the
precip, but do think we partake in at least a quarter inch of
much needed rain over the next 24 hours. Anything above that is
a bonus.

Wind flow today and tonight will be out of the east. This
combined with mostly cloudy skies will keep temperatures muted
today, down 15 degrees compared to Friday.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
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As of 430 AM EDT Saturday...

Key Messages:

1) Wedge of cool/damp air begins to erode slowly on Sunday as a
strong short wave approaches from the southwest.

2) Warmer Monday with increasing chances for thunderstorms,

The wedge of much cooler air that spreads into the region early
Saturday will begin to erode slowly by Sunday afternoon.
Temperatures will moderate back into the 70s for most areas
except perhaps the far northeastern/northern portions of the
CWA. Short wave ridging ahead of a vigorous short wave lifting
northeast from the MidSouth will also help to warm conditions
across the region by Sunday afternoon.

Spotty, mostly light precipitation can be expected again Sunday,
especially during the morning. By afternoon, enough instability
should be present across most of the CWA for isolated to
scattered thunderstorms, especially along/west of I-77. This
disturbance and increasing amplitude of the upper flow/namely
ridging in the eastern U.S. will help to lift the backdoor
front/baroclinic zone back north toward the PA/MD/WV line for
the first part of next week. Consequently, precipitation should
become a bit more spotty and less organized going into Tuesday.

Cool temperatures Sunday mostly in the 60s to lower 70s will
moderate back into the 70s and 80s by Tuesday as heights rise
aloft and the baroclinic zone lifts back north. This will in
turn allow for more sunshine with breaks in the clouds more
prevalent than during the Sun-Mon time frame.

During the period of this forecast, severe weather is not
expected with weak dynamics and increased ridging aloft.
Rainfall amounts in the Sun-Tue time frame should average around
1/2 inch, which given the antecedent dry conditions is not going
to cause any real flooding issues at this time.

/Confidence Levels in Forecast Parameters/
- Moderate to High Confidence in Temperatures,
- Moderate to High Confidence in Precipitation Probabilities,
- Moderate to High Confidence in Wind Direction and Speed,
- Low to Moderate Confidence in Thunderstorm Potential.
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&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
As of 200 PM EDT Friday...

Key Messages:

1) Confidence is moderate for chances of scattered showers and
thunderstorms each day.

2) Temperatures will head warmer by the middle of the week.

A stalled frontal boundary should still linger across the Mid
Atlantic through the middle of the week. Several weak waves of
low pressure will continue to track eastward along this
boundary to continue a daily chance of scattered showers and
thunderstorms. Meanwhile, ridging aloft and a southwest flow at
the surface should increase warm air advection to push
temperatures higher by Wednesday and Thursday. A cold front will
approach the Appalachian Mountains sometime during late
Thursday into Friday, which could spark a higher chance of
convection. The models continue to struggle with depicting when
this prolonged period of unsettled weather will come to an end
beyond this point.

&&

.AVIATION /09Z SATURDAY THROUGH WEDNESDAY/...
As of 230 AM EDT Saturday...

Cloud bases are lowering from the east. A cool easterly wind off
the Atlantic Ocean will bring marine air as far west as the Blue
Ridge resulting in a low IFR Cig today along with some partial
ridge obscurations. Patchy light rain this morning will become
more showery in nature during the day with light to moderate
showers becoming widespread for the afternoon and evening.
Thunderstorm threat appears too low to include in the TAFs
attm but do think some of the more robust convective cells will
contain lightning.

The easterly wind over the area is shallow, observed from the
surface up to about 3000 feet AGL. Above 3000 feet winds are out
of the southwest...the winds above 3Kft providing the steering
current for any deep convection...storm cell movement from SW-
NE.


Extended Aviation Outlook...

SHRA/TSRA with periods of DZ, BR, and MVFR/IFR/LIFR conditions
continue after 18Z Sunday. More diurnally driven -SHRA/TSRA are
expected Monday through Wednesday. This will bring periods of
MVFR ceilings and visibilities at times. Winds Monday through
Wednesday will be SSW and gusty at times.

&&

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

&&

$$

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