160 
FXUS61 KRLX 090102
AFDRLX

AREA FORECAST DISCUSSION
National Weather Service Charleston WV
802 PM EST Tue Jan 8 2019

.SYNOPSIS...
Possible snow squalls Wednesday into Thursday...with heavy snow 
in the mountains. More snow possible this weekend as low 
pressure passes to the south.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
As of 538 PM Tuesday...

Adjusted PoPs and Wx according to recent radar trends and latest high
resolution models through 15Z. Areas of rain showers will
probably remain over the northeast mountains through sunset.  
Keep thunderstorm threat across the northern third of the area 
through 01Z. Rest of forecast remains representative. 

As of 221 PM Tuesday...

Southwest flow continues as of writing but should become more
westerly by late afternoon as a cold front slides across.
Scattered showers may occur along the front late this afternoon,
with a rumble or two possible...can't even rule out some small 
hail with the strongest cells. The primary surge of CAA should 
then kick in around sunset with a period of strong winds 
expected late afternoon and early this evening. It should not 
take much for these winds to mix to the surface and a few hours 
of gusts of 40 to 50 mph are expected. By late evening, most of 
the precip should be confined to the NE CWA where the greatest 
lift is prog to be located. Overnight, large scale lift 
increases as a strong upper level strong advects across and the 
llvl flow becomes more northwesterly. This will begin to promote
the development of upslope flow across the NE CWA.

During the day Wednesday, northwest flow in the lower levels 
will promote an increase in moisture fetch from the Great Lakes 
in the sfc-H7 layer. This nearly saturated layer, combined with 
a rather persistent signal from guidance that steep lapse rates 
in the lowest couple hundred mb will exist, should result in 
the best chance of snow squalls we have experienced so far this 
winter season. The best chance of snow squalls (they bring 
locally heavy busts of snow, brief gusty winds, and reduced 
visibility) should occur from primarily sunrise through early 
afternoon before lapse rates weaken in the afternoon. Despite 
the chances for snow squalls lessening in the afternoon, 
steadier light snow should develop in the afternoon as the 
northwest/upslope flow persists. All in all, have issued a 
Winter Weather Advisory for the lowlands/eastern mountains for 
Wednesday to account for possibility of snow squalls and then 
steadier light snow in the afternoon. The Winter Storm Watch has
been upgraded to a Warning for the NE mountains.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
As of 215 PM Tuesday...

Northwest flow continues from the near term, thus continuing upslope 
snow showers in the north/central WV mountains along with a few 
lowland showers. Robust cold convection continues as well dropping 
Thursday morning low temperatures into the single digits in the
mountains to near 20 in the lowlands. The upper level trough 
responsible for the prolonged upslope event shifts off to the 
East and high pressure builds into the Great Lakes Thursday, 
increasing the northerly component to low-level winds locally. 
The result here is a few upslope snow showers spreading South 
into the southern WV mountains and SW VA while the lowlands 
clear out.

Upsloping winds start to relax later Thursday night, and 
moisture wanes, bringing mountain snow showers to an end. There 
is uncertainty with how long we'll be able to squeeze out 
remaining LL moisture, so a few flakes may linger into early 
Friday. Additional snowfall amounts from Wednesday night onward 
will be in the 3-5" along high ridges and mountains, tapering to
around an inch near the 79 corridor down through southern WV 
and SWVA.

A pattern shift starts Friday with cold advection ending first 
aloft, and eventually at the surface - but not before another 
especially cold morning with clearing conditions and calming 
winds lending to effective radiational cooling. Lows Friday 
morning will be in the single digit (mountains) to upper-teens 
(lowlands). High pressure traverses the Great Lakes region 
Friday with warm return flow taking hold locally, rounding out 
the work week. Upper level clouds start moving from the West in 
late in the period ahead of the next system.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
As of 250 PM Tuesday...

Southern stream energy will be advancing eastward across the 
southern US to start the long term period with a surface low 
centered in southeastern TX on Saturday morning. Recent trends have 
indicated that models have more agreement in the track that the 
surface low will take further into the weekend. At this point, 
expecting that the low pressure system will move south of the 
forecast area and emerge off the Carolina coast by Sunday morning. 
This type of track would of course be more favorable for keeping 
colder air in place and increase the opportunity of more of a wintry 
ptype, but there is increasing concern that a warm wedge situation 
may develop across the lowlands due to the inverted trough extending 
into the region. This feature may be just enough to keep 
temperatures warm enough and perhaps favor a rain/snow mix scenario, 
especially in the southern Coalfields. While considerable 
uncertainty still remains with this system, it is certainly possible 
that accumulating snow could occur given upstream forcing and the 
cold antecedent conditions, but confidence is too low to get into 
details regarding precipitation amounts. Thinking the best approach 
to this is to leave a consenus blend of POPs for this forecast 
issuance until forecast confidence increases with future model runs. 

Scattered snow showers could linger in the mountains Monday morning, 
but will gradually decrease in coverage as an expansive area of high 
pressure in the central Plains begins to build into the region from 
the west.

&&

.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
As of 0750 PM Tuesday...

VFR is still prevailing, however some MVFR can be experienced 
in RA/TS at EKN/CKB terminals this evening. SFC winds will still 
be a weather threat tonight, as the cold front moves away from 
the area. Gusts to 30+ kts is occurring throughout the area with
possible 40kt+ gusts. The westerly winds taper off late 
overnight. LLWS threat will soon diminish at HTS. 

By Wed at 18z winds veer northwest. Rain ends within the next 
few hours possibly lingering at EKN. Clouds should clear from 
the east temporarily, but expect to see MFVR ceilings roll in 
covering the entire area by morning and not going anywhere for 
the duration of the forecast period. Snow showers make way by 
morning around EKN and the mountains with lower visibility. The 
snow will progressively spread towards other terminals by the 
afternoon and stick around for the duration. Not expecting IFR 
visibility at this time, however some terminals could possibly 
see it in heavier snow showers.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z THURSDAY...
     
FORECAST CONFIDENCE: High.

ALTERNATE SCENARIOS: Ceilings possibly lower in snow showers
along with visibility dropping to temporary IFR conditions. 

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.

DATE                                                                 WED
UTC 1HRLY       00   01   02   03   04   05   06   07   08   09   10   11
EST 1HRLY       19   20   21   22   23   00   01   02   03   04   05   06
CRW CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
HTS CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
BKW CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
EKN CONSISTENCY  H    H    M    H    H    H    L    L    H    H    H    H
PKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    M
CKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H

AFTER 00Z THURSDAY...
IFR possible in snow showers Wed night through Thursday.

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...Winter Weather Advisory from 7 AM to 10 PM EST Wednesday for 
     WVZ008>011-013>020-026>031-034-515-516-524.
     Wind Advisory until noon EST Wednesday for WVZ524.
     Wind Advisory until 9 PM EST this evening for WVZ005>011-
     013>020-027-029.
     Wind Advisory until 4 AM EST Wednesday for WVZ523-526.
     Winter Storm Warning from 4 AM Wednesday to noon EST Thursday 
     for WVZ523-526.
     Winter Weather Advisory from 7 AM Wednesday to 7 AM EST 
     Thursday for WVZ032-039-040-517>522-525.
     Wind Advisory until 1 AM EST Wednesday for WVZ028-030>032-039-
     040-519>522-525.
OH...Wind Advisory until 9 PM EST this evening for OHZ066-067-075-
     076-083>087.
KY...Wind Advisory until 9 PM EST this evening for KYZ101>103-105.
VA...None.

&&

$$
SYNOPSIS...RH/MC/RG
NEAR TERM...RH/ARJ
SHORT TERM...MC
LONG TERM...MPK
AVIATION...JZ