Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Charleston WV
313 PM EDT Sat Aug 30 2014
turning hot and more humid this afternoon in deep southwest flow.
Moisture increases in that flow...with an upper level disturbances
crossings through Monday.
Near term /through Sunday/...
a change in weather pattern is expected tonight into Sunday. Radar
and satellite images show convection and associated clouds
approaching from the west across central Kentucky and along the in and
Ohio border. Eventually...clouds will thicken over southeast Ohio and
WV tonight...with showers and/or storms spreading west to east
overnight. This activity is associated with a cold front expected
to move across the area Sunday afternoon. However...convection
ahead of the front could produce strong thunderstorms with very
heavy rain Sunday into Sunday night.
Models indicate a series of 500 mb shortwaves moving across the local
area tonight. Yet another descent shortwave passes on Sunday along
the cold front...with ample low level moisture as seen on precipitable waters
exceeding 2 inches...and dewpoints in the lower 70s. Surface based
cape increases as well. Believe showers and storms will be brief
tonight...and stronger in intensity and coverage on Sunday into
Expect a mild temperatures through the period per moisture and
some temperature advection tonight under southwest flow...and
plenty of clouds and cooling showers Sunday afternoon. Went with
previous temperatures as they go along with latest bias corrected
Short term /Sunday night through Tuesday/...
second wave of showers and embedded thunder should be pushing
east/NE-Ward across the area at the outset of the short-term period 00z
Monday. This is about three or so hours slower versus previous model runs
yesterday at this time. Precipitable waters of 2-in plus also accompanying...and
there continues to be some concern for flash flooding with
repetitive training. In collab with near-term forecaster and
surrounding offices...will continue to keep flash flooding concerns
in the severe weather potential statement for now. Still expecting the bulk of the organized precipitation
to be exiting the northeast zones around the 07z-09z time frame and
overall...still anticipate a general half inch to inch of precipitation but
some higher amounts certainly still possible should training occur.
No wholesale changes made to Labor Day forecast from previous forecast. Area
still under SW flow aloft and with high dewpoints continuing...will
maintain mainly afternoon slight chance to low chance probability of precipitation area-wide
with the middle chance probability of precipitation in the northeast mountains. Middle 80s for The
Lowlands still appear on track...but with more sun may see some
upper 80s. Monday night remains warm and tranquil...but another
front approaches on Tuesday with an accompanying short wave trough in the
mean flow aloft. Brought in likely probability of precipitation across the northwest zones
by the 15z-18z time frame with these features.
Long term /Tuesday night through Saturday/...
long term period can generally be characterized by zonal flow aloft.
Leaned wpc for the most part with a few tweaks here and there. Warm
and muggy conditions will continue through the period...with no heat
waves or abnormally cool spells in sight. A cold front will push
across Tuesday night with another front approaching Sat night...with
subsequent higher probability of precipitation during those periods. In between...Thursday
and Friday look mostly sunny to perhaps partly cloudy with only
minimal chances for precipitation each day.
Aviation /18z Saturday through Thursday/...
VFR conditions will prevail for most part of the period under
partly cloudy skies as diurnal cumulus field develops. High to middle
level clouds will thicken late afternoon and tonight as a cold
front approaches from the west. Can not rule out few rain showers
during the afternoon hours at heights...bkw...and ekn today.
An upper level shortwave will accompany this front enhancing precipitation
activity. The front will bring the bulk of precipitation during the predawn
hours spreading from west to east to affect heights and pkb first
around 09-12z. Then...showers and storms are expected to move
across crw by 15z and the rest of the eastern sites through 18z
Sunday. Repetitive showers or storms could produce brief IFR
ceilings and visibilities under heavy rain. At this time...it
remains uncertain where the heavier showers will occur. Low
ceilings behind the front...or Post rainfall stratus possible late
Another upper level disturbance moves across early Monday with
another round of rain showers into the early afternoon hours.
Forecast confidence and alternate scenarios through 18z Sunday...
Forecast confidence: medium.
Alternate scenarios: timing of rain showers tonight may vary by an hour or
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.
UTC 1hrly 20 21 22 23 00 01 02 03 04 05 06 07
EDT 1hrly 16 17 18 19 20 21 22 23 00 01 02 03
crw consistency h h h h h h h h h h h h
heights consistency h h h h h h h h h h M M
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 Sunday...
IFR possible in showers/storms Sunday...and then in dense early
morning valley fog early next week.