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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KRNK 170620
AFDRNK

Area Forecast Discussion
National Weather Service Blacksburg VA
120 AM EST Mon Feb 17 2020

.SYNOPSIS...
Cold front over the Great Lakes will move southeast tonight and
dissipate over the Mid Atlantic region on Monday. A stronger
cold front will cross the eastern United States Tuesday and
Wednesday. High pressure will build in across the East
Wednesday through Friday.

&&

.NEAR TERM /THROUGH TODAY/...
As of 920 PM EST Sunday...

The forecast will be adjusted to decrease slightly the coverage
and amount of precipitation that will impact southeast West
Virginia through the early morning hours of Monday. Meso-scale
models and upstream radar trends are both supporting this
adjustment.

As of 635 PM EST Sunday...

No major changes are planned for the overall forecast for the
overnight hours. Precipitation over NC/SC is still expect to
remain mainly south of the region. A few sprinkles over the far
southeast parts of the region cannot be ruled out. Also,
isolated to scattered light rain/snow showers are still forecast
for parts of southeast West Virginia, south into the Northern
Mountains of North Carolina.

Have tweaked hourly temperatures, dew points, winds/gusts and
sky cover to better reflect the latest observations and expected
trends through the evening hours.

As of 1240 PM EST Sunday...

500 MB pattern States zonal with split flow tonight and Monday.
Deeper moisture out of Georgia and South Carolina will approach
northern North Carolina and southern Virginia by this evening
but models keep a majority of the precipitation southeast of
Danville. Band of moisture within the northern stream reaches
the mountains by late afternoon with more cloud cover crossing
the area overnight. The chance of light precipitation will
remain over the mountains mainly during the evening. Enough
cloud cover tonight and Monday to limit large diurnal
temperatures swings. Will stay close to National Blend guidance
for lows tonight and highs on Monday.

&&

.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
As of 200 PM EST Sunday...

A cold front trails from a surface low moving northeast through the
Great Lakes region. This front will approach and pass over our area
Tuesday evening into Wednesday morning, bringing a brief round of
rain with light accumulation totals, with around half an inch
falling along the mountains, where orographic effects will help
squeeze the most moisture out of the atmosphere. Most of this rain
will fall Tuesday afternoon and evening.

After the front passes it will begin to settle as a boundary in a
zonal orientation to the south of us Wednesday.  Though guidance
differs on the location where the boundary will set itself up, there
is general agreement that it will be far enough south that the
chances at receiving more rain in our CWA after Wednesday morning
are low.

Tuesday`s temperatures will be warm, with highs generally in the
50s, and the Piedmont potentially tapping into the low 60s. A slight
cooldown follows the front on Wednesday, but cloud cover should
moderate any diurnal fluctuations, with highs in the upper 40s, and
lows overnight into Thursday morning in the 30s.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
As of 200 PM EST Saturday...

An upper trough over the region Thursday will slide east and push
off the coast Thursday night into Friday. Then, the trough move out
into the Atlantic ocean during the weekend. This will allow high
pressure and upper ridging to build across our area.

High pressure over the Midwest Thursday morning will slide east to
the Ohio Valley Thursday night. The ECMWF and GFS showed a weak
shortwave rotating around the upper trough. Moisture associated with
this feature looked overdone on models. The GFS was hinting at some
light snow, around an half inch or less for the northwest mountains
of North Carolina. Overtime, the details will become clearer on this
system. Utilized the NBM for pops on Thursday. High temperatures
Thursday will range from the upper 20s in the west to the mid 40s in
the east. Under partly cloudy skies and light winds, Thursday night
will be cold with readings generally the lower teens to the lower
20s.

The high center will be overhead Friday into Friday night. Friday
will feature high temperatures in the lower 30s in the mountains to
the lower 40s in the piedmont with sunshine. Low temperatures Friday
night will vary from the upper teens in the deeper mountain valleys
to the mid 20s along the Blue Ridge.

The high center will slide Saturday into Sunday. High temperatures
on Saturday will moderate into the lower 40s in the mountains to the
lower 50s in the piedmont. Under clear to partly cloudy conditions,
low temperatures Saturday night will generally be in the upper 20s
and lower 30s. The warming trend continues Sunday with high
temperatures form the lower 40s in the west to the mid 50s in the
east. With variable clouds, low temperatures Sunday night will
moderate to the mid 30s in the west to around 40 degrees in the
southeast.

Medium to high confidence in the Long Term Forecast.

&&

.AVIATION /06Z MONDAY THROUGH FRIDAY/...
As of 100 AM EST Monday...

VFR conditions expected to prevail across the central
Appalachians through Monday...winds generally light from the
east to southeast. Wind speeds will gradually increase and
become gusty across the ridges Monday night as a cold front
approaches from the west. The front will also bring increasing
clouds with lowering cloud bases Monday night, rain arriving
Tuesday morning.

Forecast confidence = High.

Extended Aviation Discussion...

Tuesday morning, rain will be on the increase and ceilings will
trend towards sub-VFR with the approach of a cold front.

Sub-VFR ceilings and visibilities will be possible Tuesday
afternoon and night with the passage of a cold front. An abrupt
wind shift northwest will take place either late Tuesday
afternoon or early Tuesday evening. Winds will be gusty through
Tuesday evening, but decrease by daybreak Wednesday.

Residuals showers are expected across the area Wednesday. Sub-
VFR ceilings are possible still across the mountains. Colder air
filtering into the region may switch rain showers to snow
showers at the higher elevations.

VFR conditions return Wednesday night into Friday.

&&

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

&&

$$
SYNOPSIS...AMS
NEAR TERM...AMS/DS
SHORT TERM...VFJ
LONG TERM...KK
AVIATION...PM