Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Charleston WV
634 am EDT Tuesday Jul 29 2014
cooler and drier airmass through middle week.
Near term /through tonight/...
a few sprinkles across the area this morning...and have a
vorticity maximum bringing some enhancement to the cumulus rolling
through southern Ohio. Nothing on radar from iln however.
upper level trough axis will keep conditions cool and very mildly
unsettled over the middle Ohio Valley Tuesday. NAM giving a weak
trough axis embedded within the cyclonic flow...and with adequate
moisture through 700mb...a few showers and weak thunderstorms are
possible again today.
Dewpoints will keep dropping slowly as the arrival of the Canadian
airmass becomes complete. Lowland 70s and mountain 60s prominent
again...with lows in the 50s and 40s respectively tonight. Cloud
cover could make this on the tricky side and may ultimately need to
add a couple degrees. Leaned on the mav...which was the better
performing guidance last night.
Short term /Wednesday through Friday/...
an upper disturbance will rotate around the mean eastern U.S. Upper
trough Wednesday...keeping temperatures on the cool side and may
bring some light showers mostly in the north. All the
models show a healthy relative humidity field with this feature across the north.
But with lack of a low level focusing mechanism...the showers will
tend to be diurnal...widely scattered...and light. Slowly
rising heights within the mean upper trough and moderating surface
high pressure will bring mostly dry weather and a slow warming trend
Thursday. Look for temperatures to get back into mainly the lower
80s by Thursday...which is still below normal.
By Friday...although weaker...the mean eastern U.S. Upper trough
sharpens up a bit...as upper ridging over the western Atlantic Ocean
retrogrades. Surface high pressure by this time will have shifted
far enough east to increase low level moisture on a south to
southeast flow. The increased instability will bring a gradual
increase in the chance for showers...mainly on east facing slopes of
the mountains where modest upslope forcing increases. Increased
clouds Friday will hold temperatures down in the lower 80s...but
humidity will increase.
Long term /Friday night through Monday/...
there is a chance for some showers late on Friday and into the
weekend...as a system lifts up from the Carolinas. High pressure
again builds in for next week.
Used and blend of model and HPC guidance for most of the forecast
Aviation /12z Tuesday through Saturday/...
scattered-broken cumulus with isolated -shra/-tsra to affect the area
during prime heating today. No prevailing convection in the tafs
for now and is too low for the prob30 category.
Have some clouds moving in tonight in the middle levels...but some
visibility restrictions are possible. On the lower end of
confidence for now.
Isolated convection possible again on Tuesday.
Forecast confidence and alternate scenarios through 12z Wednesday...
Forecast confidence: medium.
Alternate scenarios: may need a brief tempo or amend if isolated
convection nears a terminal. May not have the valley fog tonight.
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 11 12 13 14 15 16 17 18 19 20 21 22
EDT 1hrly 07 08 09 10 11 12 13 14 15 16 17 18
crw consistency M M h h h h h h h h h h
heights consistency l l M h h h h h h h h h
bkw consistency l l l h h h h h h h h h
ekn consistency l l h h h M h h h h h h
pkb consistency l M h h h h h h h h h h
ckb consistency l M h h h h h h h h h h
After 12z Wednesday...
no significant IFR conditions expected.