Area Forecast Discussion Issued by NWS Blacksburg, VA
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000
FXUS61 KRNK 172347
AFDRNK
Area Forecast Discussion
National Weather Service Blacksburg VA
747 PM EDT Sun Mar 17 2024
.SYNOPSIS...
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A cold front heads to the coast this evening, ushering in drier
and colder air across us through Tuesday. After that,
temperatures moderate closer to normal for Mid-March. Very gusty
west-northwest winds continue at times through Wednesday. The
next chance for rainfall may occur Friday when low pressure
develops over the Gulf Coast region.-- End Changed Discussion --
&&
.NEAR TERM /THROUGH MONDAY/...
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As of 730 PM EDT Sunday...
Key Messages:
1. Colder air arrives tonight. Temperatures fall to at or below
freezing across the mountains.
2. Gusty winds Monday with cooler temperatures.
Quite a bit of high clouds interspersed with scattered to broken
high level stratocu/altocu along/behind cold front.
Very dry air will swing in from the northwest tonight and winds
will stay up all night, but some diminishing occurs toward dawn.
Forecast on track. Cannot rule out a sprinkle over the NC
piedmont into southside VA this evening as the front exits.
Previous discussion from early this afternoon...
A cold front had moved through our region today, and was
accompanied by plenty of altocumulus and gusty west winds to 35
mph or so at times. Winds decrease some tonight, but we will
still see a few strong gusts as moderate cold air advection
continues.
Skies clear out for a few hours tonight with the loss of daytime
heating and the waning influence of the surface boundary.
Tomorrow, there are indications we will see additional lee
cirrus such as we saw overnight/this morning, consisting of a
stripe of high clouds along and just downwind of the Blue Ridge
mountains. Overnight lows will be at or a few degrees below
freezing for the mountains, while the Piedmont will see mainly
upper 30s and low 40s. Any denser cloud cover could result in
warmer temperatures, however.
As Monday wears on, clouds will gradually increase in coverage
as another shot of cold air arrives after noon. The pressure
gradient will also increase as this occurs and high pressure
nears from the Midwest. A stray snow or rain shower is possible
for the Greenbrier Valley tomorrow. Expecting a coolish day
temperatures, ranging from the 30s and 40s in the mountains to
the low to mid 50s for the Piedmont. Winds will be stronger than
today, but won`t really get going until the afternoon and
evening, when gusts to 45 mph will be possible for our higher
terrain. Lower elevations will likely see gusts to 35 mph at
least.
Just a reminder: If you placed sensitive plants outside given
the recent unseasonably warm temperatures, bring these back
inside to protect them from freezing temperatures tonight.
Confidence in the near term is high.-- End Changed Discussion --
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.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
As of 110 PM EDT Sunday...
Key Messages:
1. Breezy, windy, or very windy conditions are expected for most
of this time period.
2. Small chances of light precipitation for parts of Southeast
West Virginia
3. Dry elsewhere.
During Monday night, the much advertised upper trough will cross
our region. In the wake of the passage of its axis, we are still
expecting increasing 850mb winds. Speed values peak between
roughly 35 and 45 kts during the early evening and slacken only
slightly through the night. The peak in the wind speeds is also
matched by a peak in the 6-hr pressure rises during the early
evening of around +4 to +6 mb. Pressure rises near zero mb not
long after 06Z.
On Tuesday, low level winds back slightly during the morning
hours and continue to decrease in speed. As we head into
Tuesday night, a shortwave trough is expected to cross the Great
Lakes region, with the tail of its trough axis skirting
northern parts of the area. Winds at 850mb again increase into
the 35 to 45 kt range. This first shortwave trough is followed
about twelve hours later by another early Wednesday night.
The result of the above is a period with small chances of light
upslope precipitation over the Southeast West Virginia mountains
with dry weather else where. Additionally, much of this time
period will be on the breezy, windy, or very windy side. We may
need to consider wind headlines for Monday night along and near
the crest of the Blue Ridge southwest of Roanoke.
Strong northwest winds will have the effect of helping yield
some compressional warming to slightly counter the effects of
cold air advection across eastern parts of the region.
Additionally, this pattern has traditionally resulted in dew
point values, and subsequently relative humidities, lower than
most model guidance suggests.
Confidence in the above weather scenario is moderate.
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.LONG TERM /THURSDAY THROUGH SUNDAY/...
As of 1250 PM EDT Sunday...
Key Messages:
1. Dry Thursday.
2. Rain potential Friday into Friday night.
3. Drier and windier Saturday and Sunday.
On Thursday the region will still be with in an area of dry, but
gusty, northwest flow. As we head into Friday, here is where the
biggest question mark in the forecast continues to be
positioned. We will be watching both a southern stream
trough/low progress into the Deep South. Concurrently, a
shortwave trough is expected to race across the Great Lake
region. How or if these to features interact, and the overall
path of both their centers, will play a big factor into how much
associated precipitation we receive and the timing and
potentially p-type of this precipitation. Model guidance is
still too variable to offer a moderate or high confidence
forecast, but there are some similar trends. The center of the
southern stream trough/low is expected to remain south and east
of the region. However, where the deformation zone on the
northwest side of this system tracks does come into question.
What does remain to be a reasonable call is for precipitation in
some capacity to impact our area on Friday into Friday night.
Drier and windier conditions look to follow Saturday and Sunday
as well.
Confidence in the above scenario is moderate on the synoptic
aspects but low on the mesoscale.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
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As of 735 PM EDT Sunday...
Key Messages:
1. Gusty WNW winds will diminish overnight before strengthening
even more tomorrow afternoon and evening.
Expect VFR cigs/vsbys through the period, with mainly mid and
high clouds, though some broken stratocu at times this evening
occurs across the mountains.
West-northwest winds will gust to 15-25kt this evening, then
subside late tonight only to pick up again after 15z Monday.
Some gusts could approach 30-35kts by the end of this taf period
around BCB/ROA.
High confidence in VFR, moderate on winds.
EXTENDED AVIATION OUTLOOK...
VFR conditions will prevail through Thursday, except for
possible intermittent MVFR conditions in mountain snow or rain
showers Wednesday morning at BLF/LWB.
Gusty northwest winds continue Monday night through Wednesday.
Speeds will be strongest in the mountains, potentially reaching
40 kts locally at times.
Confidence in the above aviation scenario is high.-- End Changed Discussion --
&&
.FIRE WEATHER...
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As of 740 PM EDT Sunday...
Key Messages:
1. Gusty west-northwest winds and drier air expected through
Thursday.
2. Combo of dry fuels/low RH and some gusty winds will lead to
wildfire spread uptick in portions of the NC foothills Monday.
Per coordination with NCFS and looking at dry fuels/RH 25-30
percent Monday and some gusts over 20 mph, a fire danger
statement will be in effect for Monday afternoon for Alleghany,
Surry and Wilkes Counties. RH should be higher in Ashe/Watauga
with colder temps, while winds further east in the piedmont will
be weaker.
WNW winds will relax some overnight but not totally go away.
Another strong shot of cold and dry air will result in even
stronger gusts Monday afternoon through Wednesday, with some
weakening during the nighttime. Despite cooler temperatures
arriving with the front, strong mixing associated with the gusty
winds will maintain low afternoon RH values through Thursday.
Light snow or rain showers are possible for the Greenbrier
Valley Monday afternoon and evening. The next chance for
widespread wetting rain may come Friday.-- End Changed Discussion --
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...NF/SH/WP
NEAR TERM...SH/WP
SHORT TERM...DS
LONG TERM...DS
AVIATION...SH/WP
FIRE WEATHER...NF/SH/WP