Area Forecast Discussion
Issued by NWS Charleston, WV-- Highlight Changed Discussion --
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FXUS61 KRLX 201752
Area Forecast Discussion
National Weather Service Charleston WV
1252 PM EST Fri Jan 20 2017
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 /18Z FRIDAY THROUGH WEDNESDAY/...
-- Changed Discussion --As of 1250 PM Friday...
A warm front has pushed through the region. Behind the front
there is generally broken clouds as ceilings range from VFR to
MVFR. Ceilings should continue to increase through the afternoon
as we become firmly entrenched in the warm sector. Isolated
showers will be possibly this afternoon across Northeast West
Virginia, but for the most part we will continue to dry out.
Confidence in the forecast starts to drop later tonight. There
will remain breaks in the clouds and with low level moisture in
place there is a chance that we could see some fog develop. Some
sites could possibly drop to IFR conditions.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z SATURDAY...
FORECAST CONFIDENCE: Medium.
ALTERNATE SCENARIOS: With broken clouds ceilings will likely
drop to MVFR at times. 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 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 L H H H H H H H M
HTS CONSISTENCY H H H M L H H H M M M L
BKW CONSISTENCY M M H H H H H H H H H M
EKN CONSISTENCY H H H L H H H H H H H L
PKB CONSISTENCY M H L M L L L L L L M L
CKB CONSISTENCY H M H H H L H H H H M L
AFTER 18Z SATURDAY...
IFR will be possible again Sunday through Monday with another
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