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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KRNK 190027
AFDRNK

Area Forecast Discussion
National Weather Service Blacksburg VA
827 PM EDT Thu Apr 18 2024

.SYNOPSIS...
Above normal warmth will continue into Friday followed by a
cool down for the weekend. After a clear night tonight, clouds
will be on the increase. A cold front over the Ohio Valley will
move east, crossing the Mid-Atlantic region Friday. This front
will bring showers and a few thunderstorms, but limited
rainfall. In general, expecting a quarter inch or less of rain,
with isolated amounts of one half inch where thunderstorms
occur. Temperatures will return to a more seasonal level
Saturday.

&&

.NEAR TERM /THROUGH FRIDAY/...
-- Changed Discussion --
As of 750 PM EDT Thursday...

Key Messages:

1).  Clear, Quiet Night Weather Wise,

2). Diminishing area of showers/isolated thunderstorms reach
western part of CWA around daybreak Friday morning,

3). Isolated redevelopment of scattered showers/thunderstorms
along eastward advancing moving frontal boundary Friday
afternoon.

Overnight will remain quiet and mostly clear across the region
as dry air mass settled over the region today in the wake of
yesterday`s upper-level disturbance. A frontal system of
continental-Pacific (cP) origin will move from the OH/TN valley
Friday morning into the RNK CWA by afternoon. What is currently
strong to severe convection across the MO/OH/TN Valley and
southward will merge into a narrow line of showers/thunderstorms
overnight and diminish by morning to a decaying area of
showers/light rain as it attempts to move into the antecedent
very dry air mass. Expect any chance for thunder with the
morning activity will end before and just as it reaches the
western CWA boundary, essentially evolving into an area of light
rain or perhaps even sprinkles for some areas through the mid-
morning hours as what is left of this precipitation area reaches
the Blue Ridge. Meanwhile, the frontal boundary remains back to
the west and could serve as a focus for redevelopment of
convection during the afternoon along the front and near the
Alleghany front. It remains to be seen whether or not this
scenario actually occurs. However, it is worth noting that many
of the near term models do show a broken line of convection
developing by mid/late afternoon across WV moving into western
VA before dissipating. The SPC outlook for "marginal" severe
does not seem to mesh well with the various convective model
input, with that focus more on the southern/south eastern part
of the CWA. Brooks-Craven parameters are only marginally
supportive of thunder, so the chance for robust convective
development and even more so severe looks to be rather
questionable at this point.

Otherwise, overnight weather conditions will be mostly clear
with light and variable, mostly north to northeast winds with
continued above normal temperatures mostly in the 50s. Keep in
mind that normal low temperatures this time of year should be in
the 40-45 range. Friday will remain warm in advance of the
front, but a bit cooler than Thursday with cloud cover and
scattered precipitation.

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

Previous Near Term Forecast Discussion...

As of 230 PM EDT Thursday...

Key Message:

1. Clear Tonight, Cloudy Friday

2. Scattered showers and thunderstorms Friday.

Dry weather expected through tonight under mainly clear skies.
Some increase in cloud cover is anticipated late tonight in
advance of an approaching MCS from the Ohio Valley.

Friday, a cold front will sweep across the eastern U.S. in
advance of a mid-level trough, providing enough low-level ascent
to support scattered showers and a few thunderstorms across our
forecast area. Timing is critical with models bringing 1 or 2
rounds of activity across the mountains Friday. First wave of
activity is expected to be pre-frontal...basically the remnants
from Thursday`s Ohio Valley MCS. Model consensus is to bring
this across the mountains Friday morning, but weakening with
time. The morning activity may dictate whether there will be
redevelopment during the afternoon. Morning clouds and precip
tend to hinder or significantly delay afternoon deep
convection. Convective allowing models suggest redevelopment
along the actual cold front Friday afternoon, but hesitant on
building up enough CAPE to support anything significant with
respect to coverage or severity. For now will broad brush the
pops, weighting the highest chance from measurable rainfall
across the mountains (0.25 to 0.50) and then to a much lesser
extent east of the Blue Ridge (0.10 or less).

In spite of cloud cover Friday, it will remain warm with
temperatures remaining above the seasonal norm...highs in the
70s.
-- End Changed Discussion --

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/...
As of 300 PM EDT Thursday...

Key Messages:

1: Clouds linger early Saturday, then clearing.

2: Temperatures cooler but seasonal.

Cold front passage Friday night will bring seasonably cool air
into the region from the northwest. Clouds may linger but
precip threat should wane as subsidence increases.

The actual front is expected to settle just south of our area
in the Carolinas, but high pressure to our north will nose its
way into the areas keeping rain chances suppressed mainly south
of the VA/NC border. Clouds are expected to thin across the
Virginias, but persist over the Carolinas.

Temperatures should return to near normal with highs ranging
from the 60s mountains to the lower 70s piedmont.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
As of 150 PM EDT Thursday...

Key Messages:

1: Rain chances Sunday and Wednesday

2: Cooler than normal temperatures Sunday and Monday, rebounding on
Tuesday

High pressure centered over the southern Plains will stretch
eastward over Virginia, helping to keep most of the area dry Sunday.
Meanwhile, a disturbance in eastern Texas will track to the east
across the Gulf States, then along a surface boundary over the
Carolinas. Latest models are trending a more southern track with
this disturbance, which will reduce rainfall coverage over RNK`s
forecast area to just along and south of the VA/NC border. Timing of
rain continues to be Sunday afternoon, exiting east in the evening.
A cold front will sweep across the region as this disturbance moves
off the Carolina Coast. High temperatures Sunday will range from the
mid 50s west of the Blue Ridge to the mid 60s east. These
temperatures are 5F-10F cooler than normal.

The center of the southern Plain ridge will move over the area
Monday, keeping temperatures slightly cooler than normal. A warm
front is expected to pass over the region Tuesday, allowing
temperatures to become warmer than normal. A strong cold front is
expected to pass over the area Wednesday, dropping temperatures
below normal to end the week.

&&

.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
-- Changed Discussion --
As of 800 PM EDT Thursday...

Key Messages:

1). VFR conditions prevail overnight except MVFR possible KBLF-
KLWB and westward after 09Z,

2). Decaying area of precipitation with MVFR ceilings spread
into the western parts of the CWA after 12Z,

3). Scattered showers/thunderstorms potentially redevelop along
frontal boundary and near Alleghany Front mid-late Friday
afternoon.

Synopsis:

A frontal system of continental-Pacific (cP) origin will move
into the forecast area late Friday. Pre-frontal convection
overnight across the OH/MO/TN Valley will reach the western
portion of the CWA around daybreak into the mid-morning Friday
in a significantly diminished fashion. Remnant clouds and
scattered light showers will dissipate as they reach the Blue
Ridge and Piedmont. Remnant cloud cover will inhibit convective
redevelopment until mid-late afternoon as the actual frontal
boundary drifts into the western part of the CWA near the
Alleghany Front. Scattered thunderstorms potentially may
redevelop at this point per several near-term model solutions.

Ceilings...VFR ceilings expected overnight except perhaps MVFR
ceilings drifting into the far western areas late and developing
east of the Blue Ridge from LYH-DAN as southeast upslope flow
evolves in those areas late tonight/early Friday. GFS model
wants to generate IFR ceilings across the Piedmont Friday
morning, but not quite ready to buy off on this given antecedent
dry air mass and limited fetch of Atlantic moisture.

Visibilities...VFR visibilities are expected throughout the TAF
valid period with the exception of isolated pockets of MVFR in
-SHRA or isolated TSRA in the afternoon.

Winds...Winds will veer, or already have veered in many
instances, to the northeast overnight. Winds will continue to
veer to the southeast early Friday in response to the
approaching weather system. Winds will become southwest late
Friday morning as a remnant convective outflow boundary moves
through the area, then west to northwest late Friday behind the
actual cold front. Speeds expected overnight 5-8kts, then
7-12kts Friday with some gusts to 20kts following frontal
passage.

/Confidence Levels in Forecast Parameters/
- Moderate Confidence in Ceilings after 10Z, otherwise High
  Confidence,
- High Confidence in Visibilities,
- Moderate Confidence in Wind Direction and Speed.

Extended Aviation Outlook...

The aforementioned cold front will exit to the south and east
of the CWA by Saturday. Some MVFR ceilings may linger across the
Alleghanies and Cumberland mountains in eastern WV to southwest
VA Saturday morning. North winds will provide some clearing for
late Saturday, but more moisture may surge northeastward during
Sunday and Monday to bring another chance of rain as low
pressure rides across the southeastern states. Confidence in the
later scenario is quite low at this time.
-- End Changed Discussion --

&&

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

&&

$$

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