Area Forecast Discussion Issued by NWS Blacksburg, VA
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KRNK 151630
AFDRNK
Area Forecast Discussion
National Weather Service Blacksburg VA
1230 PM EDT Fri Mar 15 2024
.SYNOPSIS...
A cold front works across the area this afternoon and evening.
Disturbances will progress through the Great Lakes region Sunday
into Monday with mainly gusty and colder conditions the impact
on our region.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 949 AM EDT Friday...
Key Messages:
1. Showers will be increasing in coverage but thunderstorms will
be limited as will rainfall amounts.
A lull in activity at the moment with main areas of convection
across the southern Appalachians into the Gulf Coastal states.
12z RNK sounding showing a couple inversion in the 900-800mb
range, and since clouds are moving in faster, seems instability
will be more limited, so have backed off on thunder til this
afternoon mainly confined it east of the mountains and moreso
over the NC/VA piedmont.
Looking at the prefrontal trough already in the piedmont with
the actual front stretching from PA-central KY into west TN.
This front enters our mountains by late afternoon. Will see
increased shower coverage late this morning across the NC
mountains/foothills where better deep moisture convergence lies
with limited coverage further north. Latest high-res models vary
on coverage with limited coverage along/north of
Blacksburg/Roanoke. Temperatures started out warm, so bumped
them up especially in the piedmont though showers/clouds should
slow the rise somewhat in the west.
Previous discussion...
Persistent trough has shown signs of weakening/losing structure
and CAM consensus agrees on this trend as it approaches the
western CWA in the next few hours. This feature is well ahead of
the sfc cold front which currently looks to be back in
Ohio/Indiana. While the front may take it`s time under mainly
zonal flow aloft, the deep layer moisture and perhaps a weak
disturbance could allow for some redevelopment of convection
during the day today. Progged SBCAPE could get near 500 J/kg
along with daytime heating but this may be limited with any
persistent cloud coverage/solar sheltering. All this being said,
it`s possible some of the area could have a lull or skip in
development while the Piedmont may get a bit greater chance
later today if they are spared from some of the remnant clouds.
There is more certainty on the decrease of pops going into this
evening as the drier airmass behind the front finally advects
SEWD. Some low stratocu could fill in to allow for a cool cloudy
start to the weekend, though quickly scattering/mixing out
after the morning.
Confidence of shower/storm coverage today is low to medium.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY NIGHT/...
-- Changed Discussion --
As of 1220 PM EDT Friday...
Key Messages:
1. Mild through Sunday before a rapid cool down.
2. Gusty to very gusty northwest winds expected.
3. Limited amounts and coverage of rain/snow showers for SE WV.
During this portion of the forecast, troughing across the US East
Coast is expected to amplify. First, one sharp shortwave trough is
expected to head east through the Great Lakes region. An 850mb front
will cross our region Saturday night into Sunday in response. A
second shortwave trough is expected shortly after the passage of the
first which is expected to progress into a longwave trough centered
over most of central CONUS by Monday morning. The axis of this
longwave trough is expected to be above our area by the start of
Monday evening.
The result of the above transition is expected to be the following.
Winds will turn gusty from the northwest Sunday night into Monday.
Southeast West Virginia upslope rain/snow showers will be possible
during this time with dry weather elsewhere. Monday night into
Tuesday, with the passage of main trough axis we expect a boost in
the northwest winds, leading to a continuation, if not a bit of an
increase, in the Southeast West Virginia upslope precipitation.
Although, but Monday night, drier air entering the region may
mitigate the ability for any notable precipitation amounts.
East of the crest of the Blue Ridge, these persistent northwest
gusty winds will lead to subsidence which should greatly limit cloud
cover, add a bit of compressional warming to slightly offset the
impacts of cold air advection, and allow for likely drier than model
forecast dew points to occur at the surface.
Temperatures during this portion of the forecast are expected to be
above normal through Sunday, but switch quickly to near or slightly
below normal by Monday.
Confidence in the above weather scenario is moderate to high.-- End Changed Discussion --
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
-- Changed Discussion --
As of 1205 PM EDT Friday...
Key Messages:
1. Mainly dry through Thursday.
2. Turning much wetter Thursday night into Friday.
3. Trending milder through the period.
During this portion of the forecast, the synoptic pattern is
expected to transition from a relatively dry northwest flow cross
our region Tuesday/Wednesday to a much wetter pattern by Friday.
This will be thanks to low pressure on Tuesday near the Four Corners
region, slowly progressing eastward and deepening as it moves through
the Deep South on Friday. As early as Thursday night, southerly flow
in advance of this low will start advecting moisture into our region
within a region of isentropic lift. For Friday, there are
differences within the guidance as to the track of the low, but all
in some capacity offer a wet Friday for the region.
Temperatures during this portion of the forecast are expected to
trend milder through the period.
Confidence in the above weather scenario is moderate to high on the
overall synoptic transition, but low in regards to the specifics on
the path and impact of the upper low on Friday.-- End Changed Discussion --
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
As of 700 AM EDT Friday...
Some remnant light rain could impact LYH and BLF early this
morning from a decaying cluster of showers and storms.
Otherwise showers and possible TSRA later this morning into
afternoon with cigs mainly 4-10 kft then mainly MVFR cigs this
evening into overnight behind the front and precip (possibly
lower cigs and VSBYs for LYH and BLF). Winds today SW to west
increasing 9-14 kts and possible gusts near 20 kts, then
becoming more NW under 10 kts for this evening/overnight.
Confidence in the above aviation scenario is low to medium.
EXTENDED AVIATION OUTLOOK...
Saturday through Saturday night, VFR conditions will prevail.
Sunday into Monday, increasing and gusty northwest winds will
bring a return of some sub-VFR clouds to the Southeast West
Virginia mountains, along with isolated to scattered rain/snow
showers.
Confidence in the above aviation scenario is moderate.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...DS/WP
NEAR TERM...WP/AB
SHORT TERM...DS
LONG TERM...DS
AVIATION...SH/AB