-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KRNK 211604
AFDRNK

Area Forecast Discussion
National Weather Service Blacksburg VA
1204 PM EDT Sun Apr 21 2024

.SYNOPSIS...
Low pressure across the southeast along a frontal boundary will
bring light rain into southern Virginia and North Carolina
today. Dry weather is expected Monday and Tuesday. Temperatures
the next few days will be cooler than normal.

&&

.NEAR TERM /THROUGH MONDAY/...
As of 639 AM EDT Sunday...

Key Messages:

1) Light rain today mainly mainly south and east of the VA Blue
Ridge.

2) Frost in the mountains Monday morning.

Rain is exiting the west rather quickly, so some modest changes
to the PoP forecast were made to dry out the west a bit faster.
Otherwise the forecast has not received any updates of note.
Main concern going forward today will be to monitor the timing
of the wave leaving to the east, and when rain will end
altogether, as well as how quickly skies clear in the mountains
with an influx of drier air.

Previous discussion...

Frontal boundary lies from southeast NC into the Florida Panhandle
early this morning deep moisture convergence showing up as far north
as the GA/Upstate SC line. Regional radar shows light rain shifting
as far north as the Smokys and reaching Asheville, NC.

The latest Hi-Res FV3 shows this better than other models, but in
general models favor surging light rain as far north as the NC/VA
border by mid morning, with potential patchy light rain as far north
as a Blacksburg-Lynchburg line by midday-early afternoon.

The 00z Synoptic models GFS/ECMWF/NAM show pretty good agreement on
how far north the rain line reaches but how much actually falls and
amounts to 0.01" is questionable as dry air to the north very well
could keep this rain limited further south.

Temperatures this morning starting off milder in a few spots leading
to a tough high temp forecast as any rain falling into the drier air
will likely keep temperatures from rising much. Leaning toward a
blend of MAV/MET MOS for now with highs in the 50s for most, with
some 40s in the mountains.

Expect the low riding along the front and upper energy to push east
away from the area by evening, with clearing skies and colder lows
tonight. Even though the growing season has not officially started
in the mountains, there are still some with delicate/tender plants
already in bloom, so be aware that patchy frost is likely in the
mountains Monday morning, with even freezing temperatures in
portions of Greenbrier Valley/Burkes Garden and the higher ridges of
Grayson County into NC. Lows elsewhere will range from the mid 30s
New River Valley to upper 30s to around 40 east.

Forecast confidence is above average on sky cover today, but
moderate/average on temps/pops, and then on frost/lows tonight.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
-- Changed Discussion --
As of 1145 AM EDT Sunday...

Key Messages:

1. Dry conditions for Monday night and Tuesday.
2. Light rain arrives by early Wednesday morning.
3. Patchy frost possible Monday night and Wednesday night.

With high pressure passing overhead Monday night, we can expect
chilly overnight lows under clear skies and light winds that
will make for efficient radiational cooling. Lows will bottom
out in the low to mid 30s, cool enough to support patchy frost,
and will likely touch freezing in some of the mountain valleys.

High pressure will slide off the southeast coast on Tuesday,
with southwesterly winds becoming established ahead of our next
cold front. Afternoon high temperatures will be near normal for
the second half of April, ranging from the mid 60s to the low
70s. Showers will arrive during Tuesday night into Wednesday
morning, though won`t progress much past the crest of the Blue
Ridge, breaking up in the downslope windflow. Rainfall will
remain modest for most, ranging from a few tenths of an inch
locally across southeast West Virginia and western Virginia, to
a few hundredths further east for the remainder of the
mountains and foothills.

High pressure building in behind the passage of the cold front
across our area Wednesday afternoon will build east from the
Great Lakes to New England during the evening, and will then
wedge southward across the Mid-Atlantic. This will result in a
cool northeasterly windflow across our area by sunrise Thursday
under mostly clear skies. Temperatures will again fall into the
low/mid 30 for areas west of the Blue Ridge, however winds may
remain just strong enough to limit the potential for frost
formation, but will not outright eliminate it.
-- End Changed Discussion --

&&

.LONG TERM /THURSDAY THROUGH SATURDAY/...
-- Changed Discussion --
As of 1200 PM EDT Sunday...

Key Messages:

1. Cooler than normal temperatures for Thursday, warmer Friday
and Saturday.
2. Rain chances increase for Friday.

Cool high pressure, centered over New England on Thursday, will
control our weather pattern. Given the east to northeasterly
windflow off of the Atlantic, kept afternoon highs a few degrees
below model forecast guidance. May see a few sprinkles develop
along the Blue Ridge Thursday night as marine air is carried
into the higher terrain.

Chances for shower activity will increase for Friday and
Saturday as a deep low pressure system exits the central Rockies
and advances toward the Great Lakes, with an associated warm
front lifting northward across the Tennessee and Ohio River
Valleys. That stated, still some uncertainty of the timing of
when any rainfall will arrive for our area. Winds shifting more
southerly by this time will allow for a gradual warm up of
afternoon temperatures that will be closer to normal for late
April.
-- End Changed Discussion --

&&

.AVIATION /16Z SUNDAY THROUGH THURSDAY/...
As of 636 AM EDT Sunday...

Mainly VFR conditions are expected through the 22/12Z valid TAF
period.

Mid clouds this morning with light rain at BCB/ROA/LYH, with dry
conditions at BLF/LWB and sub-VFR at times at DAN closer to the
low pressure system and better upper support. Most of the
rain/sub-VFR around DAN should be pushing east by this
afternoon. Winds will generally be out of a northwest to
northeast direction north of a front through the period and
light, except for a few gusts later today along/west of the Blue
Ridge to 20kts..

Extended Aviation Outlook...

Drier air will return Sunday night and Monday as high pressure
builds eastward across the Mid Atlantic to provide good flying
weather through Tuesday. Another cold front will arrive during
Tuesday night into Wednesday to bring the next potential for
MVFR ceilings and rain showers in the mountains. Thursday looks
dry and supporting of VFR.

&&

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

&&

$$

SYNOPSIS...PM/WP
NEAR TERM...VFJ/WP
SHORT TERM...NF
LONG TERM...NF
AVIATION...NF/PM/WP