Area Forecast Discussion
Issued by NWS Charleston, WV-- Remove Highlighting --
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FXUS61 KRLX 201729
Area Forecast Discussion
National Weather Service Charleston WV
129 PM EDT WED JUL 20 2016
High pressure in control with dry and stable air. Getter hotter.
Weak disturbances could drop southeast around ridge Friday night
.NEAR TERM /THROUGH THURSDAY/...
as of 17z...daytime heating forming cu over the central and
southern counties. Further north...air drier...so cu will struggle
to form. Temperatures continue to rise faster than mos guidance
and more along our trace with a hotter maximum temperature around
21z. Winds remain light with strong surface heating.
With the lower dew points...have minimum temperatures lower at
dawn Thursday than dawn Wednesday. Lowered minimum from our
previous forecast for northern counties and central mountains with
the lowest late afternoon dew points. Still have river valley fog
forming first in southern coal fields of WV and cooler mountain
valleys. Overall...a bit later in forming and less coverage than
06z to 12z Wednesday.
Will try to stay on high side of maximum temperature guidance for
Thursday as top soil gets drier. Winds remain light. Dew points
remain aob normal levels during the afternoon.
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
Upper ridge continues to strengthen and build eastward at the start
of the period...with an increase in heat and humidity as we progress
into the weekend. Dew points will gradually climb into the 70s by
Friday into the weekend...and this combined with temperatures in the
90s...will create heat indices over 100 across much of the lowlands
Friday into the weekend. Will continue to highlight this in the
HWO...as it is looking more and more likely heat advisories will be
Most of the period should remain relatively dry...however...there
exists the possibility of disturbances aloft moving southeast into
the region at times...triggering showers and thunderstorms...with
heavy downpours expected with any storms. Still a little too far out
to determine exact timing and path of any
disturbances...but...maintained a general chance to slight chance in
the forecast at times during the period
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
The heat will continue thru much of the extended with this weekend
serving as the apex as the upper level ridge axis plagues the
central parts of the country...keeping the extreme heat at bay
thankfully. Still...highs in the low to mid 90s with dewpoints in
the lower 70s will create heat index values likely eclipsing the
100 degree mark Saturday and Sunday. Will keep the mention of
potential heat advisories in the current HWO. A caveat in
realizing such thresholds will depend on areal coverage of any
convection. A moisture axis from the upper level wave that comes
thru Friday night may linger on Saturday as the ridge axis makes
subtle changes. This may provide the lift for aftn convection once
any mid level cap is broken. We have included some chance pops in
for Saturday afternoon...centered over SE OH. Our far NE zones may
stay capped to keep the day dry. Another upper level wave will
help to flatten the ridge some on Sunday and especially early next
week with increased threat for shra/tsra.
.AVIATION /17Z WEDNESDAY THROUGH SUNDAY/...
High pressure and light winds with vfr prevailing...except for
local ifr in fog 07z to 12z Thursday. Fog should be later in
forming and less coverage than dawn Wednesday.
Scattered cumulus this afternoon...briefly broken over central
and southern mountain counties this afternoon...mainly at 3 to 5
thsd ft agl. Air drier Pkb to Ckb vcnty on north with less cu
CONFIDENCE AND ALTERNATE SCENARIOS...
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z THURSDAY...
FORECAST CONFIDENCE: High.
ALTERNATE SCENARIOS: With cooler temperatures...fog could be
briefly thicker than forecast at Crw for an hour or 2 near dawn.
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
EDT 1HRLY 11 12 13 14 15 16 17 18 19 20 21 22
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 H H H H H H H H H H
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY H H H H H H H H H H H H
AFTER 18Z THURSDAY...
No widespread IFR expected.