820 
FXUS61 KRLX 201515
AFDRLX

Area Forecast Discussion
National Weather Service Charleston WV
1015 AM EST Fri Jan 20 2017

.SYNOPSIS...
Active pattern returns with a warm front crossing overnight 
into Friday, followed by a stronger system early next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 1015 AM Friday...

Rainfall has just about exited our forecast area with just a few
isolated showers lingering behind the warm front. Have updated
PoP based on latest Radar. Also, temperatures are running a
couple degrees above the previous forecast so decided increase 
highs for this afternoon a few degrees, especially with the 
holes in the cloud cover that is currently showing up on visible
imagery to our SW. 

As of 815 AM Friday...

Looks like rain is going to lift out a bit sooner than
previously forecast so updated PoP based on current Radar and
blend of the last 4 HRRR model runs. Looking at the latest
observations and METSAT it appears that the warm front is just
south of Charleston and will continue to push NE this morning.
Also, I adjusted sky cover a bit with this update based on
current METSAT as there are some holes in the clouds and some 
areas will likely see a few breaks of sun today. Have not 
adjusted high temperatures for the day yet, however, depending 
on the cloud cover we could see highs climb a few degrees above 
the current forecast. It is still going to be warm and in the 
60s for most of us even if we don't see much sunshine today. 

As of 6 AM Friday...

Warm front lifting rapidly to the northeast, and extrapolating 
back edge of rain with the front puts into the southern Coal 
Fields by 12Z. Most of the precip will exit to the northeast by
noon with the front, although there may be a lingering rain 
shower behind the warm front for a couple of hours. Otherwise, a
mostly dry and much warmer afternoon is in store for the area.

As of 310 AM Friday...

Models in good agreement on a strong Pacific upper trough 
slamming into the western U.S. today. This will, in turn, cause 
the central Plains upper low to open up and lift rapidly 
northeast across the Ohio Valley today. It will move through our
region as a negatively tilted upper trough and surface warm 
front. However, this system will be weakening overall as more 
energy is used to flatten the strong eastern U.S. upper ridge in
place. While dynamics and moisture will certainly be enough to 
support a band of rain showers with the warm front, the QPF for 
us will be less compared to what has fallen to our west 
earlier. This will be due to both the best QPF lifting up thru 
Ohio and the speed of the system. We look for less than a half 
inch of rain in general before the rain ends later this morning 
from southwest to northeast. Thus, no water problems are 
expected at this time from this system. Behind the warm front 
will be a surge of warm air despite a lot of clouds, with highs 
this afternoon into the 60s. While we cannot rule out a stray 
shower this afternoon in the warm sector, it will mostly be just
dry and warm. Tonight will be dry and quite mild in the warm 
sector with lows again well above normal.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
As of 315 AM Friday...

5h ridge axis shifts east of the forecast area on Saturday with
slight drying trend to start the period. Then flow trajectories
shift more toward the southwest as another warm front surges 
north with over running precipitation. Atmospheric dynamics 
weak, and will carry general chance pops and lighter qpf amounts
into saturday night. 

Longwave trough axis then starts a trend to shift eastward late in 
the period, perpetuated by a decent piece of energy working along 
the southern periphery across the Tennessee Valley. Models tend to 
keep best dynamics and moisture across southern half of our forecast 
area with sfc low passing across NC.   

Temps will remain well above normal through the period, with all 
precipitation falling as rain through Sunday night.  There even be a 
few lighting strokes Sunday afternoon.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
As of 315 AM Friday...

Surface low tracks across to our south and then rides northward up 
the East Coast with Mid Atlantic region remaining in a warm airmass. 
Late in the period we see further indication that a change in 
the longwave pattern is afoot, with cooler airmass working its 
way into the upper midwest. By Thursday, we should see 
temperatures return to more seasonal values. Noted some 
variation with model solutions regarding the extended period. 
Thus, used a general model blend throughout the period with a 
few minor tweaks to pop and temperature values.

&&

.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
12Z Friday thru 12Z Saturday...

As of 605 AM Friday...

A warm front will push northward across the area and exit the
northern portions by early afternoon. This will provide 
ceilings lowering into the MVFR range with rain ahead of the 
warm front, and for a few hours behind the warm front. Some 
brief IFR conditions are also possible in the heavier rain, 
especially west of the Ohio River, and possibly on some of the 
east facing slopes of the northern WV mountains. However, do not
think it will be widespread enough to include in the major TAF 
sites. VFR ceilings will return in the warm sector, spreading 
from southwest to northeast, except remaining MVFR ceilings in
the northern mountains including EKN. Isolated showers can not 
be ruled in the warm sector this afternoon, especially north,
but it will be mostly dry. Light easterly winds early, becoming
southerly 5-12 KTS in the warm sector this afternoon.

After 00Z Saturday, look for breaks in the clouds. If winds 
decouple enough and early, there may be some river valley MVFR fog
after 07Z affecting most of the major TAF sites, except IFR at 
EKN after 09Z. 

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z SATURDAY...
     
     
FORECAST CONFIDENCE: Medium. 
   
ALTERNATE SCENARIOS: Timing of lowering ceilings and rain 
restrictions could vary later overnight and Friday morning. Fog
development tonight may be more widespread than forecast.

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       15   16   17   18   19   20   21   22   23   00   01   02
EST 1HRLY       10   11   12   13   14   15   16   17   18   19   20   21
CRW CONSISTENCY  H    M    L    L    L    L    H    H    H    H    H    L
HTS CONSISTENCY  M    L    L    L    H    H    H    H    H    H    H    M
BKW CONSISTENCY  H    H    H    L    L    L    H    H    L    L    H    L
EKN CONSISTENCY  L    H    H    H    H    M    M    M    M    M    M    L
PKB CONSISTENCY  H    H    H    H    H    L    M    H    H    H    H    L
CKB CONSISTENCY  H    H    H    H    H    M    M    M    H    H    H    L

AFTER 12Z SATURDAY...
IFR will be possible again Sunday through Monday with another 
system.

&&

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

&&

$$
SYNOPSIS...KMC/JMV
NEAR TERM...JMV/MPK
SHORT TERM...TRM
LONG TERM...TRM
AVIATION...JMV