Scientific Forecaster Discussion
fxus61 krlx 202343
Area forecast discussion
National Weather Service Charleston WV
743 PM EDT Tue Aug 20 2019
upper level disturbances could produce showers or storms
through Wednesday. Cold front brings rainfall Thursday. Dry and
cooler this weekend.
Near term /through Wednesday/...
as of 740 PM Tuesday...
Coverage of storms on the increase as the upper level wave moves
through the Ohio Valley. Pop forecast looked pretty good with
values coming up over the west and south, and remaining lower
over the central County Warning Area. New outflow boundaries could become a game
changer however, so some adjustments likely will be needed
based on trends in 2-3 hours.
As of 225 PM Tuesday...
Sent a quick update to issue a excessive heat advisory for
portions of southeast Ohio and southeast Kentucky through 6 PM.
As of 205 PM Tuesday...
The area remains under the influence of a surface high pressure, and
an upper level low amplitude trough. Models bring few h500 vorticity
maxes across the area through Wednesday. These short waves will
likely interact with limited moisture to produce scattered
showers or storms. Models suggest a healthy h500 vort Max will
move across our northwest sections by 00z this evening, perhaps
bringing another cluster of storms into southeast Ohio and
northern WV. Convective activity should diminish in intensity
and coverage later tonight.
Similar low temperatures can be expected tonight, generally in the
upper 60s lowlands, ranging into the low 60s northeast mountains.
With some clouds around, but despite of near calm flow, less River
Valley fog can be expected overnight tonight. This could change over
areas that receive rainfall this afternoon and evening.
Short term /Wednesday night through Friday night/...
as of 230 PM Tuesday...
Unsettled weather continues on Wednesday, as weak disturbances cross
the area, with isold to sct showers and storms. A few storms could
be strong to severe with damaging winds the primary threat. Storm Prediction Center has
added a marginal risk to the County Warning Area for Wednesday.
A cold front will move into the area Thursday night and Friday, with
continued showers and thunderstorms across the area. Front will be
across southern zones on Friday, with drier weather across northern
zones for the most part.
With the overall warm and humid atmosphere in place, heavy downpours
and localized water issues will be a possibility during the period,
particularly if areas receive repetitive convection.
Long term /Saturday through Tuesday/...
as of 230 PM Tuesday...
Brief break in the precipitation across most areas over the weekend
with high pressure briefly in control. Showers and storms will still
continue to be a possibility, particularly across the higher terrain
and southern zones, where humidity will be higher in vcnty of front,
just to south of southern zones.
Heat and humidity will be on the increase towards the end of the
week into early next week as the front lifts north across the area
again, along with several disturbances, bringing a return of active
weather to the region.
Aviation /00z Wednesday through Sunday/...
as of 740 PM Tuesday...
Low confidence in the aviation forecast going forward given the
ongoing convective activity.
Scattered storms becoming slightly more numerous across the area
has forced The Hand at some terminals for some storm based
restrictions. Still tried to remain conservative however, which
could mean the need for amds.
Beyond the storms, if terminals do get rain, the fog potential
does go up, if the convective debris in terms of high and mid
level cloud cover are able to dissipate late in the overnight.
Some outflow boundaries from area storms are now evident on
radar. This could play havoc with the surface wind directions in
the vicinity of older storms, and also create new storms. This
is possible at heights over the next couple of hours especially.
Winds in storms can easily reach 40kts, and small hail is also
Forecast confidence and alternate scenarios through 00z Thursday...
Forecast confidence: low.
Alternate scenarios: location of convection could vary. Areas of
fog could be larger than expected. Sky forecast is dependent on
overall coverage of storms.
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 Wednesday 08/21/19
UTC 1hrly 00 01 02 03 04 05 06 07 08 09 10 11
EDT 1hrly 20 21 22 23 00 01 02 03 04 05 06 07
crw consistency h h h h h h h M l l l M
heights consistency h h h h h h h M M M M h
bkw consistency h h h h h h h h h h M M
ekn consistency h h h h M M M M M M M M
pkb consistency h h h h h h M M M M M M
ckb consistency h h h h h h h h M h h h
After 00z Thursday...
IFR possible with showers and storms mid week, stratus and
valley fog redeveloping by Friday morning.