Area Forecast Discussion
Issued by NWS Blacksburg, VA

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FXUS61 KRNK 211434

Area Forecast Discussion
National Weather Service Blacksburg VA
1034 AM EDT Sun Apr 21 2024

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.


As of 639 AM EDT Sunday...

Key Messages:

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

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.


As of 145 AM EDT Sunday...

Key Messages:

1. Dry conditions for Monday and Tuesday.
2. Light rain arrives by early Wednesday morning.
3. Cooler than normal temperatures, patchy frost possible Monday

Surface high pressure settles along the eastern US for the beginning
of the work week. This will keep Monday and Tuesday dry, but with
temperatures a few degrees cooler than normal. With a clear and calm
night expected Monday night, patchy frost is possible in the
mountain valleys.

By Tuesday, a surface low pressure system will track across southern
Canada and the Great Lakes, with a cold front trailing southward.
This front is expected to reach the Mid Atlantic from the west,
bringing light rain to the mountains, by Wednesday morning.
Most of the rain will be to the east of the area by Wednesday
night, and high pressure pushes back into the area. The greater
moisture will be farther to the south, so rainfall amounts will
likely be less than a tenth of an inch along and south of the
VA/NC border.


As of 200 AM EDT Sunday...

Key Messages:

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

After the frontal passage on Wednesday, surface high pressure builds
back into the area. With a colder airmass behind said front,
temperatures will fall back to below normal for Thursday. The high
shifts offshore heading into the weekend, while a low pressure
system develops in the Great Plains by Friday. The warm front
associated with this system looks to lift northward into the upper
Midwest and Great Lakes, stretching into the central
Appalachians. This will bring the next chance of rain to the
area, with the greatest probabilities along and west of the Blue
Ridge. Ahead of this front, slight ridging at 500mb develops
over the Gulf of Mexico, which will help temperatures trend a
few degrees warmer for Friday and Saturday.


As of 636 AM EDT Sunday...

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

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.





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