Forecast Discussions mentioning any of "ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 02/06/19

Area Forecast Discussion

National Weather Service Blacksburg VA

 640 PM EST Tue Feb 5 2019

.SYNOPSIS...
A weak front will waver across the Appalachians and central Mid
Atlantic region through midweek, bringing very warm
temperatures but also some showers to the area. A cold front
will then move through the region on Friday with another chance
of showers and a surge of colder air moving in for the weekend.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
As of 630 PM EST Tuesday...

Latest update really only chose to push back the timing slightly
for onset of precip moving into western areas per latest HRRR
guidance. This should verify nicely as returns in western
Greenbrier are limited and likely virga. Initial isolated precip
that is expected tomorrow is still well off into central KY and
southern OH. Will probably need to update temperatures again
shortly to ascertain exactly how quickly the valleys will be
radiating out in the coming hours but as of now, low temperature
forecast seems on track.


As of 130 PM EST Tuesday...

Satellite imagery indicates clouds are a bit less widespread
than expected and temperatures this afternoon are responding
accordingly. Most locations east of the Blue Ridge are into the
70s early this afternoon with some maxes peaking near record
territory, but where the clouds are hanging tough temperatures
remain in the 50s. There may also be some patchy drizzle or
sprinkles west of the Ridge especially along the hilltops.

As low pressure moves into the Ohio valley it will push the
diffuse frontal boundary back to the north a bit, keeping the
Appalachians and central Mid Atlantic region mostly dry for the
overnight period. However, we will stay to get into better
isentropic lift toward morning which will bring us a steadily
increasing chance of showers into Wednesday. The bulk of
precipitation on Wednesday will be found west of the Blue Ridge
and primarily up near the Interstate 64 corridor. Precipitation
will decrease steadily further to the south and east with just
some scattered afternoon showers for Southside and the Piedmont.

Lows tonight will remain mild with readings remaining in the
40s. Wednesday also looks warm, though a bit cooler than today
with highs generally mid/upper 60s east to upper 50s/lower 60s
west.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
As of 230 PM EST Tuesday...

The frontal boundary will continue to lift northward as a warm
front during Wednesday night into Thursday. As the front pushes
northward, the Mid Atlantic will enter the warm sector of an
organizing low pressure system over the central Plains. Although
clouds may hold tough north of Interstate 64, some partial
clearing could occur to the south by Thursday afternoon. With
strong southwest flow aloft to provide warm air advection, high
temperatures were steered toward the warmer MET guidance for
Thursday. As a result, some locations in Southside Virginia and
the North Carolina may flirt with 80 degrees. The climate
section below addresses the records that will be in jeopardy
during this unusual February warm spell.

The aforementioned warm spell comes to a close by Friday as a
potent cold front passes overhead. Model guidance is consistent
that limited moisture will accompany the frontal passage, so
only a chance of light showers has been advertised. Confidence
is increasing for winds to reach or exceed advisory criteria
behind the front during Friday afternoon into early Friday night.
A large area of high pressure from western Canada exceeding
1040 mb combined with deepening low pressure over eastern Canada
will bring pressure rises of about six millibars every six
hours between 7 AM Friday morning and 1 AM Friday night. Low
temperatures for Friday night were nudged downward to highlight
the effects of cold air advection and clearing skies.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
As of 300 PM EST Tuesday...

The upper level pattern becomes more zonal for this weekend, so
this shot of cold air should not last too long. High pressure
should shift offshore toward Sunday, which will turn the flow
to the southwest. By Sunday night, the models diverge on how
quickly an approaching frontal boundary arrives from the west.
The GFS shows a slower solution than the ECMWF, and this
discrepancy in timing may cause some precipitation type issues
during early Monday morning.

A residual wedge of high pressure east of the Blue Ridge will
try to hold against increasing warm air advection and southwest
flow aloft on Monday. Discrepancies in the model solutions over
how strong this high will be along with its position leave this
portion of the forecast in doubt on whether any light wintry mix
may occur in the higher elevations. At this time, the forecast
will favor mainly cold rain as there are concerns that the high
may not end up in the best spot to really force the cold air
southward. The frontal boundary will stall over central
Virginia, which should set up a prolonged cloudy and wet period
throughout Monday and Tuesday.

&&

.AVIATION /23Z TUESDAY THROUGH SUNDAY/...
As of 630 PM EST Tuesday...

Conditions will be VFR to begin the TAF period. Prevailing flow
will turn more southerly during the overnight hours, allowing
for increased moisture to come into the region. This will result
in sub-VFR conditions under low cigs and fog tonight,
particularly in the mountain valley locations. As a cold front
approaches from the west tonight into tomorrow, sub-VFR
conditions will spread east of the Blue Ridge as well. Rain
showers should arrive in the mountains tomorrow morning,
beginning as isolated in nature before becoming more abundant
leading into the afternoon hours. While showers making it into
the piedmont tomorrow will be possible, the bulk of the precip
will remain over the higher elevations.

Winds will generally be light through the period with little
impart to aircraft operations.


Extended Aviation Discussion...

Pattern remains unsettled into midweek with the next threat of
rain and sub-VFR conditions being late Wednesday into Thursday.
SCT MVFR rain and snow showers are possible on Friday, with with
strong northwest winds behind the front Friday afternoon/night.
Lower cigs appear to linger in them mountains into Saturday with
VFR in the foothills/piedmont.

&&

.CLIMATE...
As of 415 AM EST Tuesday...

Unseasonably warm temperatures may set a few records for the
dates and record type below:

Tuesday Feb 5th Record High Maxes:
Bluefield 69 (2008)
Roanoke 74 (2008)
Danville 73 (2008)
Lynchburg 75 (2008)
Blacksburg 69 (2008)

Wednesday Feb 6th Record Warm Lows:
Bluefield 47 (2008)
Roanoke 56 (2008)
Danville 56 (2008)
Lynchburg 56 (2008)
Blacksburg 45 (2008)

Thursday Feb 7th Record High Maxes:
Bluefield 66 (2017)
Roanoke 73 (2017)
Danville 74 (2017)
Lynchburg 72 (2017)
Blacksburg 66 (2017)

&&

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

&&

$$
SYNOPSIS...MBS
NEAR TERM...JR/MBS
SHORT TERM...PW
LONG TERM...PW
AVIATION...JR/MBS
CLIMATE...AL