Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Charleston WV
157 PM EDT Friday Jul 29 2016
an upper level trof will keep the weather unsettled into early
next week. Upper level ridging may bring a warmer, quieter
interlude during the middle of next week.
Near term /through Saturday/...
latest radar mosaic shows scattered showers and thunderstorms
were developing across the region at this time. With continued
heating...expect the areal coverage to continue to increase.
Models indicate a trough axis will approach the forecast area from
the west tonight and then remain in the area on Saturday. Several
disturbances will move through the upper level flow, one this
evening and another on Saturday.
The disturbance this evening should result in some showers and
storms overnight. However, expect the areal coverage to decrease
with the loss of sunshine.
With abundant low-level moisture in place, expect a repeat of
last night with some stratus and valley fog developing.
Expect conditions will slowly improve after sunrise with some
sunshine possible by late morning.
Another disturbance will combine with daytime heating and low-
level moisture to result in the development of showers and storms
by late morning on Saturday. The storms should become more
numerous across northern and western portions of our forecast area
and because of this, I have gone with likely pops in those areas.
Precipitable water values still expected to be around two inches with each of
these features. This moisture and light deep layer flow will
continue to support locally heavy downpours.
Because temperatures looked good, I did not make any significant
Short term /Saturday night through Monday night/...
continued hot and humid Sunday and Monday...with frontal boundary
continuing to hang out across northern zones. Weak disturbances in
the flow...as well as daytime heating...will trigger rounds of
showers and thunderstorms at times...but overall...coverage should
be less than in recent days.
Long term /Tuesday through Thursday/...
overall...drier to start next week...with high pressure...surface
and aloft in control. Upper ridge strengthens across the area mid
week...with increasing temperatures. Looking at generally diurnal
showers and thunderstorms...mostly in the mountains...although a
slight chance cannot be completely ruled out elsewhere. Frontal
boundary approaches late in the extended...but at this point...lots
of uncertainty in timing.
Aviation /18z Friday through Wednesday/...
showers and thunderstorms with MVFR, local IFR, conditions will
continue to develop across the area into the evening hours.
Outside of these storms, VFR conditions should prevail.
With the loss of daytime heating, expect areal coverage and
intensity will decrease. Abundant moisture and an upper level
disturbance could result in a few storms continuing overnight.Undant
In addition, fog and low clouds are likely to form again
overnight tonight, but with higher clouds and possible
precipitation, predictability of associated IFR conditions is low.
After sunrise on Saturday, conditions should improve. However...
showers and thunderstorms should once again develop after 16z.
Light southwest winds should become light and variable tonight and
then become light southeast again by late Saturday morning.
Confidence and alternate scenarios...
Forecast confidence and alternate scenarios through 18z Saturday...
Forecast confidence: medium.
Alternate scenarios: coverage of storms could be higher than
expected today and tonight. The fog and low cloud forecast for
overnight tonight depends upon higher clouds and precipitation. A
thunderstorm may directly impact an Airport with IFR conditions
anytime through 18z Saturday.
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 M M l
heights consistency h h h h h h h h h h h 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 M M l
pkb consistency h h h h h h h h h h h M
ckb consistency h h h h h h h h h h h M
After 18z Saturday...
IFR conditions in low clouds and/or fog during the overnight into
the morning hours each day, and briefly in showers and
thunderstorms mainly Monday afternoon and evening.