Area forecast discussion
National Weather Service Charleston WV
251 PM EDT sun may 19 2013
Synopsis...
upper trough axis slowly passes tonight/Monday. New front moves
across Wednesday and Thursday. Cooler high pressure Friday and the
weekend.
&&
Near term /through Monday/...
upper trough axis moving to the east and an agonizingly slow
rate...and has already set off numerous small showers with a few
thunderstorms. Clearing this morning over the tug Fork valley
eventually spread out over most of the area...eliminating the
cloud debris from the activity yesterday and the saturated low
levels overnight with early mixing. But this early heating has
already reached the convective temperatures and in the
end...another day with scattered convection is already ongoing.
Not anticipating water issues with this round of convection.
The other trick to the forecast...as has been with the last few
days...is determining the extent of the cloud cover overnight.
Past nights have seen just enough clearing over wet surfaces to
give Stout River Valley fog. Last night...most places were
overcast eliminating that possibility...again...less the tug Fork
valley. Feeling is some reduced visibilities are possible again
for the early commute Monday morning.
Upper ridge moves into the western zones for Monday...reducing
chances of convection in that area with some stability aloft.
Expecting a warm up with rises in the 850mb temperatures from the
lower to upper teens celsius. Best chance of convection ultimately
lies over the higher terrain Monday.
&&
Short term /Monday night through Tuesday night/...
weak ridging dominates the eastern third of the U.S. This period as
upper level low and associated cold front across the upper Midwest
slowly shifts eastward toward the Ohio Valley. High temperatures for
Tuesday near 90 degrees following MOS trends. There will still be
enough low level moisture around for diurnally driven shower
development through the period.
&&
Long term /Wednesday through Sunday/...
approaching low pressure system tracks along the Great Lakes
Wednesday and drags one front through Wednesday night...followed by a
secondary front Thursday which will be the leading edge of a cool
Canadian high pressure system. Models in much better agreement on
this two pronged attack of the progressive fronts. With lots of
moisture and instability with the first front...will continue with
existing high probability of precipitation and thunder. Even with the second front on
Thursday...despite some loss of moisture...cooling aloft and still
good dynamics with the front will bring another round of high probability of precipitation
with some thunder.
Much cooler and drier will filter in for Friday into the weekend as
strong Canadian high pressure drops south out of central Canada.
&&
Aviation /19z Sunday through Friday/...
convection ongoing as has been the case over the last few days.
Carry thunderstorms in the vicinity/vcsh for most locations...with a few tempos for
terminals. Brief restrictions down to MVFR possible in
shra/tsra...and keep the overall forecast conservative.
Questions arise over River Valley fog potential overnight. Trend
the terminals down to at least MVFR late in the overnight
period...with IFR in the realm of possibilities at ekn/ckb/pkb.
Upper ridge approaches for Monday...and have reduced the
convection chances for the western terminals.
Forecast confidence and alternate scenarios through 18z Monday...
Forecast confidence...medium.
Alternate scenarios: tempos for rain showers/thunderstorms and rain may not have been needed
over the afternoon hours in hit or miss convection. Questions
linger on fog potential 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 18 19 20 21 22 23 00 01 02 03 04 05
EDT 1hrly 14 15 16 17 18 19 20 21 22 23 00 01
crw consistency h h h h h h h h h h h M
heights consistency h h h h h h h h h h h M
bkw consistency h h h h M M M M M M M M
ekn consistency h h h h h M M M M M M l
pkb consistency h h h h h h h h M M M M
ckb consistency h h h h h h h h h h h M
After 18z Monday...
late IFR fog possible Monday night.
&&
Rlx watches/warnings/advisories...
WV...none.
Ohio...none.
Kentucky...none.
Virginia...none.
&&
$$
Synopsis...kmc/26
near term...26
short term...jmv
long term...jmv
aviation...26
