Area Forecast Discussion
Issued by NWS Charleston, WV
FXUS61 KRLX 211923
Area Forecast Discussion
National Weather Service Charleston WV
223 PM EST Sat Jan 21 2017
Unseasonably warm into the beginning of next week. Upper trough
moves overhead Sunday. Stronger upper low Sunday night and
Monday, exiting Tuesday.
.NEAR TERM /THROUGH SUNDAY/...
As of 210 PM Saturday...
Unseasonably warm temperatures continue today and through
Sunday. Even with mid and upper level clouds overspreading the
region we have still seen widespread temperatures in the low to
mid 60s. Generally, most of the area will remain dry through
tonight as short wave passes just to our east. However, model
guidance is still uncertain with meso guidance bringing
measurable precip across the entire CWA, while the NAM, GFS, and
ECMWF keep QPF along the Eastern Mountains. Current thinking is
that the decent mid level instability is making meso models
overdo QPF amounts. Based on forecast soundings it is very dry
below 10K feet so likely we will see some very light rain or
sprinkles in the Ohio Valley and the Lowlands as most of the
returns currently on Radar is falling as VIRGA.
I have kept some slight chance PoP in the Lowlands, but
expecting very little in the way of any rainfall. Low level
moisture is a little more intact across the Eastern Mountains
and have left chance PoP here, but again the bulk of the forcing
is to our east and any measurable rainfall is likely to hug our
border with Blacksburg`s CWA.
Another stronger upper trough ahead of the closed upper low
will lift over our region tomorrow and likely spread showers
from south to north starting late in the morning. Guidance is in
fairly good agreement with having this first wave through the
area in the afternoon with a lull in the action before the more
robust closed low arrives late tomorrow night.
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
As of 220 PM Saturday...
A deep and strong mid latitude cyclone will cross south of the area
Monday night into Tuesday. The consensus among synoptic models
suggest the sfc low will cross the area west to east. The further
south the trajectory of its center, more colder air will move in and
the better probability to produce snow. With the current trajectory,
even when ice will be present aloft, temperatures at H850 and
sfc don`t cool down to below freezing. Therefore, kept liquid
PCPN Sunday night into Monday. Once the parent low move east of
the Appalachians, colder air in the back slash of the cyclone
will allow for snow showers over the higher elevations northeast
mountains Monday night into Tuesday.
Confidence runs high allowing likely to categorical PoPs Sunday
night and Monday.
The flow remains from the north Tuesday bringing drier and
fresh temperatures through mid week.
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
As of 220 PM Saturday...
By wednesday, the flow turns southeast ahead of an approaching
new low pressure system across the Great lakes with frontal
boundaries affecting the area. This system will bring much
colder air evident in H850 temperatures reaching minus 7
Thursday night. Sfc temperatures will drop below freezing
allowing liquid PCPN to transition to all snow Thursday night
.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
As of 1245 PM Saturday...
Upper level disturbance pushing into the region this afternoon
and evening, but mostly spreading overcast mid and upper level
clouds overhead. There is a low chance for a shower across the
West Virginia Mountains this afternoon and evening as this
system heads NE, but not enough confidence to put into BKW or
EKN TAFs at this time.
Most sites will remain VFR throughout the period, but
thinking with the abundant low level moisture still in place that
mountain valleys may see IFR fog develop again late tonight.
Finally, at BKW ceilings may lower to IFR overnight with
persistent moist southeasterly upslope flow.
Ceilings will start to lower tomorrow morning everywhere with
warm advection ahead of our next system. This system will bring
scattered showers to the region but timing will be towards the
end of the TAF period.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z SUNDAY...
FORECAST CONFIDENCE: Medium.
ALTERNATE SCENARIOS: Fog may not develop tonight at EKN due to
increased mid and upper level cloud cover. Showers this
evening could bring lower ceilings to BKW than currently
highlighted in the TAF. Timing of onset of precip and lower
ceilings tomorrow may bring MVFR ceilings before 18Z Sunday for
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 H H M
BKW CONSISTENCY H H H H H H H H H H M L
EKN CONSISTENCY M M M M M M M M M M M L
PKB CONSISTENCY H H H H H H H H H H H L
CKB CONSISTENCY H H H H H H H H H H H M
AFTER 18Z SUNDAY...
IFR will be possible again Sunday through Monday with another