Area Forecast Discussion
Issued by NWS Charleston, WV-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KRLX 190639
Area Forecast Discussion
National Weather Service Charleston WV
239 AM EDT FRI AUG 19 2016
Weak upper level disturbances cross Friday and Saturday, then a
cold front crosses Sunday morning. Cool canadian high pressure
then takes hold for the early and middle part of next week.
.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --As of 240 AM Friday...
No significant changes were necessary to the previous forecast.
Weak shortwaves progged to move through the region today...along
with diurnal heating...will help to trigger showers and
thunderstorms once again. Storms will contain heavy
downpours...and be slow to move...but not overly concerned with
water issues as should be not overly widespread in nature.
Appears best location for activity today will be across the coal
fields and southwest Virginia...with activity decreasing late this
Overnight...expecting patchy fog and stratus to once again
develop...along with temperatures continuing to remain in the
upper 60s to lower 70s most locations.
-- End Changed Discussion --
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
As of 200 pm Thursday...
At the start of the period...an axis of
moisture associated with a weak short wave trough will be
positioned in the far southern reaches of the forecast area. PoP
chances will remain elevated in SW Virginia through Saturday
morning as both NAM and GFS solutions hold back the southern
advancement of slightly drier air at mid levels. Relative minimum
of PoP chances will occur early on Saturday afternoon before a
cold front and associated moisture move in from the west later in
The big change in this forecast package involves the timing of the
cold front passage this weekend. The NAM solution has a
considerably more progressive movement to the system than in
recent days. With support from the latest GFS as well...have
fairly high confidence in moving the timing of the precipitation
associated with the cold front to early Sunday morning...with the
actual front passing in the late morning to early afternoon hours.
With this change in timing comes a change in the likelihood for
thunder...given a relative minimum in diurnal influences at the
time of passage throughout the forecast domain.
The progressive nature of the front will likely limit any flooding
potential with rainfall that does fall...despite a surge of low
and mid-level moisture ahead of the system. Some precipitation
will likely linger as moisture gets hung up in the eastern
mountains...and have maintained slight chance PoPs in those
locations as a result.
Temperatures updated with latest MOS/WPC averages early in the
period...with a slightly cooler trend on Sunday given more rapid
advancement of the cold front.
.LONG TERM /MONDAY THROUGH THURSDAY/...
As of 200 pm Thursday...
By Monday morning...any lingering moisture associated with the
cold front should have been eradicated from the eastern
mountains. Dry and cooler air will filter in behind the front as
an airmass with Canadian origins settles in over the Ohio Valley.
High confidence continues for a dry and more comfortable weather
pattern through Thursday afternoon. As mentioned in previous
outlooks...seasonable early morning fog will likely develop in the
climatologically favored locations underneath the ridge next
Our next chance for precipitation will likely wait until later
Thursday evening as a front...indicated on both the ECMWF and
GFS...approaches from the west.
Slightly lowered morning lows from Monday through Wednesday given
downward trend on ECMWF and GFS ensemble guidance. No major
adjustments to daytime highs through the period.
.AVIATION /07Z FRIDAY THROUGH TUESDAY/...
As of 145 am Friday...
Widespread mvfr/ifr fog and stratus developing across the area
this evening. Will generally improve to VFR conditions after 13Z
with light surface winds. Convection will fire again...mainly
after 15-16Z...with greatest coverage across southern West
Virginia and southwest Virginia...creating brief MVFR and IFR
conditions. Much of the convection will die down after 02Z.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z SATURDAY...
FORECAST CONFIDENCE: High...except low with fog.
ALTERNATE SCENARIOS: Timing and density of fog overnight could vary.
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 FRI 08/19/16
UTC 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17
EDT 1HRLY 02 03 04 05 06 07 08 09 10 11 12 13
CRW CONSISTENCY H L L L M L L M L M M M
HTS CONSISTENCY H H M M L L L M M M M M
BKW CONSISTENCY H L L M L L L M H H H H
EKN CONSISTENCY L L L L L L L M M H H H
PKB CONSISTENCY M M M L M M M L M L H H
CKB CONSISTENCY H M M L M L M M H H H H
AFTER 06Z SATURDAY...
Brief IFR conditions in scattered showers and thunderstorms Friday
evening, Saturday and Sunday, and in fog and stratus most mornings.