Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Charleston WV
1028 PM EDT sun Sep 21 2014
high pressure behind the strong cold front builds in Monday
night...and dominates our weather through the remainder of the
week with warm days and cool nights.
Near term /through Monday/...
no big changes in late evening update from the early evening update.
At 02z...our County Warning Area in Post frontal dry slot.
00z Monday 850 mb temperature at iln and pbz down 5 to 6 degrees c from 12z
Sunday. We still expect that strong cool air advection at 925 to 850
mb to form lowering stratocumulus from northwest to southeast overnight. Thinking
maximum moisture/clouds in the cool pool...08z to 16z. Left slight
chance of a light shower in the northeast counties late
tonight/early Monday. Clouds thin and lift slightly after that
maximum time period.
Due to the early evening rain in the deep southern WV valleys...have
continued some fog there through about 06z..before the drier air
infiltrates all those nooks and crannies.
Short term /Monday night through Wednesday/...
a very tranquil and dry weather pattern is indicated by all the
models...which is expected at this climatologically driest time of
the year. High pressure at the surface and aloft will dominate the
region. There will be plenty of sunshine each day and mostly clear
skies at night. The combination of mostly clear skies and dry air
will lead to chilly temperatures Monday night...and some northern
Mountain Valley frost early Tuesday morning cannot be ruled out.
Otherwise...expect a wide range in diurnal temperatures with highs
generally in the lower to middle 70s and lows in the 40s for the low
lands. Leaning on the warmer side of guidance by day and lower side
Long term /Wednesday night through Sunday/...
surface high pressure will slide to the East Coast by Thursday and
allow a modest increase of low level moisture from the east and
southeast through Sunday. However...upper ridging aloft will hold.
So while some low level moisture will return as time GOES on...the
prospects of any rain are very low at best. The low level moisture
banking up against east facing slopes of the mountains will only
bring increased clouds by the weekend. Otherwise...sunshine will
dominate west of the mountains. There will be a slow warming trend
with highs to around 80 by the weekend and lows generally in the 50s
in the low lands.
Aviation /03z Monday through Friday/...
cold front moving across mountain counties at sunset with dew point
gradient near ckb to crw.
Have some fog possible in the deep southern West Virginia valleys
01z through 06z due to recent rains. Dew points in those valleys may
be slow to drop overnight...but did figure the gradient wind and
drier air aloft...will eventually win out...even in those deeper
Dry slop in wake of front with mostly scattered clouds 4 to 6 thousand
feet. As cooler air advects in...was slower in dropping ceilings in
the cool pool. Think the maximum coverage of ceilings near 2 to 3
thousand feet with 1 to 2 thousand feet over WV mountains 08z to 15z Monday.
Few spotty light rain showers possible ckb to ekn vicinity during that
18z Monday to 00z Tuesday...ceilings lifting and scattered out at 2
to 4 thousand feet.
Forecast confidence and alternate scenarios through 00z Tuesday...
Forecast confidence: medium.
Alternate scenarios: ceilings do not lower as quickly 06z to 12z
Monday. Dew point at crw does not lower as quickly as expected with
some fog forming by 06z.
Experimental table of flight category objectively shows consistency
of weather forecast office 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 Monday 09/22/14
UTC 1hrly 02 03 04 05 06 07 08 09 10 11 12 13
EDT 1hrly 22 23 00 01 02 03 04 05 06 07 08 09
crw consistency h h h h h M h h h h h h
heights consistency h h h h h h h h h h h h
bkw consistency h h h M M M M M M M M M
ekn consistency M M M h M h l l l l l l
pkb consistency h h M M M h h h h h h h
ckb consistency h h M M h h h h h h h h
After 00z Tuesday...
in the chilly air...local IFR valley fog possible early Tuesday
morning...especially along rivers and in better sheltered valleys.