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FXUS61 KRLX 121809
AFDRLX

Area Forecast Discussion
National Weather Service Charleston WV
109 PM EST Wed Dec 12 2018

.SYNOPSIS...
A weak cold front washes out over southeast Ohio tonight.
Strong storm set to impact the area by late week.

&&

.NEAR TERM /THROUGH THURSDAY/...
As of 955 AM Wednesday...

Previous forecast on track. No changes necessary attm.

As of 230 AM Wednesday...

A surface high pressure area departs east, as a strong mid
level shortwave moves east into Lake Michigan this afternoon.
This shortwave will produce a weakening cold front, expected to
reach southeast Ohio by midnight tonight.

Upper level clouds will gradually increase today, with mid
level clouds reaching southeast Ohio by mid afternoon. The cold
front will pass over the Ohio Valley this evening, and into
West Virginia around midnight. Bufkit sounding show a moisture
layer withing 2000 to 4000 feet with dry air above and below.
No crystal generation expected. Precipitation will start falling
from a mid deck, evaporating while saturating the column downwards
across the northwest sections early tonight. This will lead to
drizzle across portions of southeast Ohio, and northern West
Virginia tonight through the overnight hours. Some snow flakes
could be possible along the highest peaks of our northeast
mountains. Even a period of freezing drizzle will be possible
along the eastern slopes of Pocahontas county overnight tonight
before all pcpn exits east of the mountains by early Thursday
morning.

West southwest boundary layer flow will turn southerly by noon,
to bring a relatively warmer airmass over the area. Went with a
blend between the super blend and bias corrected SREF guidance
for temperatures through the period.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
As of 315 AM Wednesday...

Any drizzle or freezing drizzle should quickly come to an end
Thursday morning. WAA will send temperatures soaring during the
day, with highs likely climbing into the 50s across a large
portion of the forecast area, even with mostly cloudy
conditions.

The model suite of guidance is still showing our strong upper
level low pressure system pushing into the SE U.S Thursday night
into Friday morning. However, thereafter there is significant
spread in the track of the upper low. The GFS is still the
furthest north and would have the most rainfall for our area,
while the Euro solution has consistently not budged from a much
further south track and thus rainfall amounts would be far less.

There still appears to be a very brief window Friday morning
where freezing rain along the east slopes of the Appalachian
Ridge will be possible. However, this will depend on the timing
of the precipitation and the much slower Euro would bring
precipitation into the area after surface temperatures have
risen above freezing around mid morning. Due to the significant
differences between the guidance at this time, still feel that a
blend of model guidance for this period is the best way to go,
until confidence increases. This gives less than an inch of QPF
for the entire region, but due to the uncertainty and the
significant snowfall in some areas last weekend, I will still
continue to highlight the possibility for heavy rain and
flooding in the HWO.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
As of 340 AM Wednesday...

What happens in the long term is still going to depend where the
upper low tracks. As the further north GFS solution would would
pull cold air into the region behind the system and upslope snow
showers would be possible in this scenario. However, the further
south Euro solution would maybe just bring a brief shot of cold
air Monday night, before ridging builds back in with warm air
advection on Tuesday. The GFS would build ridging back in later
Tuesday night into Wednesday. Like in the short term period, due
to the uncertainty at this range, a blend of guidance is the
best approach at this time. After the ridge does build in, the
guidance agrees that it should hold through at least the middle
of the week.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
As of 155 PM Wednesday...

VFR Vsbys/cigs through this evening. Weak low pressure system
tracks across the Great Lakes tonight and early Thursday
morning. A Weak cold front will cross the area and then wash out
over the WV mountains overnight. Cirrus deck over the area will
continue to move eastward and out of the area by late this
afternoon and evening. As the cold front approaches from the
west High and mid-deck clouds will increase tonight. Behind the
front, MVFR stratus deck between 06Z-12Z will cover much of the
area. Areas of patchy -DZ possible from PKB-CKB-EKN line, with
EKN briefly going IFR Cigs/Vsbys in sprinkles/drizzle and fog
between 09Z-12Z. Gradual improvement to VFR from west to east
towards 18Z Thursday.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z THURSDAY...

FORECAST CONFIDENCE: High to medium.

ALTERNATE SCENARIOS: Timing of MVFR/IFR ceilings could vary
overnight.

EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH:   TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW:    TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.

UTC 1HRLY       18   19   20   21   22   23   00   01   02   03   04   05
EST 1HRLY       13   14   15   16   17   18   19   20   21   22   23   00
CRW CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    M
HTS CONSISTENCY  H    H    H    H    H    H    H    H    H    M    M    M
BKW CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
EKN CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
PKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    M    M
CKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    L    M

AFTER 18Z THURSDAY...
IFR in stratus possible in rain Friday into Sunday.

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...None.
OH...None.
KY...None.
VA...None.

&&

$$
SYNOPSIS...JS/RPY/RG/MEK
NEAR TERM...JS/MPK
SHORT TERM...MPK
LONG TERM...MPK
AVIATION...JS

FXUS61 KRLX 121854
AFDRLX

Area Forecast Discussion
National Weather Service Charleston WV
154 PM EST Wed Dec 12 2018

.SYNOPSIS...
A weak cold front washes out over southeast Ohio tonight.
Strong storm set to impact the area by late week.

&&

.NEAR TERM /THROUGH THURSDAY/...
As of 955 AM Wednesday...

Previous forecast on track. No changes necessary attm.

As of 230 AM Wednesday...

A surface high pressure area departs east, as a strong mid
level shortwave moves east into Lake Michigan this afternoon.
This shortwave will produce a weakening cold front, expected to
reach southeast Ohio by midnight tonight.

Upper level clouds will gradually increase today, with mid
level clouds reaching southeast Ohio by mid afternoon. The cold
front will pass over the Ohio Valley this evening, and into
West Virginia around midnight. Bufkit sounding show a moisture
layer withing 2000 to 4000 feet with dry air above and below.
No crystal generation expected. Precipitation will start falling
from a mid deck, evaporating while saturating the column downwards
across the northwest sections early tonight. This will lead to
drizzle across portions of southeast Ohio, and northern West
Virginia tonight through the overnight hours. Some snow flakes
could be possible along the highest peaks of our northeast
mountains. Even a period of freezing drizzle will be possible
along the eastern slopes of Pocahontas county overnight tonight
before all pcpn exits east of the mountains by early Thursday
morning.

West southwest boundary layer flow will turn southerly by noon,
to bring a relatively warmer airmass over the area. Went with a
blend between the super blend and bias corrected SREF guidance
for temperatures through the period.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
As of 315 AM Wednesday...

Any drizzle or freezing drizzle should quickly come to an end
Thursday morning. WAA will send temperatures soaring during the
day, with highs likely climbing into the 50s across a large
portion of the forecast area, even with mostly cloudy
conditions.

The model suite of guidance is still showing our strong upper
level low pressure system pushing into the SE U.S Thursday night
into Friday morning. However, thereafter there is significant
spread in the track of the upper low. The GFS is still the
furthest north and would have the most rainfall for our area,
while the Euro solution has consistently not budged from a much
further south track and thus rainfall amounts would be far less.

There still appears to be a very brief window Friday morning
where freezing rain along the east slopes of the Appalachian
Ridge will be possible. However, this will depend on the timing
of the precipitation and the much slower Euro would bring
precipitation into the area after surface temperatures have
risen above freezing around mid morning. Due to the significant
differences between the guidance at this time, still feel that a
blend of model guidance for this period is the best way to go,
until confidence increases. This gives less than an inch of QPF
for the entire region, but due to the uncertainty and the
significant snowfall in some areas last weekend, I will still
continue to highlight the possibility for heavy rain and
flooding in the HWO.

&&

.LONG TERM /SUNDAY NIGHT THROUGH TUESDAY/...
As of 155PM Wednesday...

Model guidance consensus for the long term remains inconclusive
for how the pattern will look once the disturbance from over the
weekend migrates towards the eastern seaboard. The GFS shows
only a brief lull in showers for the Lowlands Monday with the
mountains still embedded underneath moisture, while the ECMWF
shows more quieter conditions after Sunday night. Hopefully in
the next few days models will be able to agree on whether an
upper level disturbance over the Great Lakes region will drop
down Monday and bring about the aforementioned showers analyzed
on the GFS, or stay above the Canadian border and allow ridging
to build in quicker. Maintained a blended forecast for the
Monday time frame with the small possibility of POPs over the
mountains during the afternoon. Once this small event kicks out,
high pressure is expected to build in through midweek.

&&

.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
As of 155 PM Wednesday...

VFR Vsbys/cigs through this evening. Weak low pressure system
tracks across the Great Lakes tonight and early Thursday
morning. A Weak cold front will cross the area and then wash out
over the WV mountains overnight. Cirrus deck over the area will
continue to move eastward and out of the area by late this
afternoon and evening. As the cold front approaches from the
west High and mid-deck clouds will increase tonight. Behind the
front, MVFR stratus deck between 06Z-12Z will cover much of the
area. Areas of patchy -DZ possible from PKB-CKB-EKN line, with
EKN briefly going IFR Cigs/Vsbys in sprinkles/drizzle and fog
between 09Z-12Z. Gradual improvement to VFR from west to east
towards 18Z Thursday.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z THURSDAY...

FORECAST CONFIDENCE: High to medium.

ALTERNATE SCENARIOS: Timing of MVFR/IFR ceilings could vary
overnight.

EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH:   TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW:    TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.

UTC 1HRLY       18   19   20   21   22   23   00   01   02   03   04   05
EST 1HRLY       13   14   15   16   17   18   19   20   21   22   23   00
CRW CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    M
HTS CONSISTENCY  H    H    H    H    H    H    H    H    H    M    M    M
BKW CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
EKN CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
PKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    M    M
CKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    L    M

AFTER 18Z THURSDAY...
IFR in stratus possible in rain Friday into Sunday.

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...None.
OH...None.
KY...None.
VA...None.

&&

$$
SYNOPSIS...JS/RPY/RG/MEK
NEAR TERM...JS/MPK
SHORT TERM...MPK
LONG TERM...MEK
AVIATION...JS