Scientific Forecaster Discussion
fxus61 krlx 200738
Area forecast discussion
National Weather Service Charleston WV
338 am EDT Sat Jul 20 2019
potentially dangerous heat conditions expected today. Sunday
will only be slightly less hot. Cold front Monday/Monday night.
Cooler, drier next week.
Near term /through tonight/...
as of 255 am Saturday...
The hot and humid conditions continue across the area today,
under the influence of high pressure, that continues to dominate
much of the country. Still thinking temperatures this afternoon
will be a degree or two higher than Friday as 850 temps warm,
and this combined with the high humidity, will warrant the
continued need to excessive heat warnings and advisories. Went
ahead and based on current calculations and expanded the heat
advisory down into southwest Virginia counties, and expanded the
excessive heat warning into Braxton and Clay counties.
As with Friday, most areas should remain dry today, although
there is a very slight chance for a pop up shower, particularly
across far southern counties from moist southwesterly flow.
Another muggy night expected overnight, with clouds, and chances
for precipitation increasing towards the end of the period in
advance of the next system.
Short term /Sunday through Monday night/...
as of 335 am Saturday...
The increase in cloud cover and chances for showers and storms
on Sunday should limit the heat a bit across the cwa, but the
high dewpoints and temperatures near 90 may still raise some
heat related issues for the day. That said, this is the last day
of the heat as the upper levels become more active with the
exit of the ridge aloft.
As The Heights begin to fall, a weakness in also evolves over
the Tennessee Valley that will end up being the primary focus
for the Sunday convection. A few bands of mid level
frontogenesis expected to form along the Ohio River. Not long
after, expect the surface baroclinic zone to drop into southern
Ohio, taking its time as it does so until the upper trough axis
can drive it through the mountains. This should be a late Monday
into Monday night time frame. Expecting some wind potential with
storms as low/mid level flow strengthens. Also, the potential
for multiple rounds exists, especially on Monday/Monday night.
Flow turns northerly and will get a wholesale airmass change
behind the cold front.
Long term /Tuesday through Friday/...
as of 335 am Saturday...
Cooler, lower dewpoints, and drier for the long term. Going from
heat indices over 100 today to high temperatures in The
Lowlands Tuesday that may not reach 80f. Blending the guidance
in the long term keeps the dewpoints in the 50s for a few days,
which could keep lows in the 50s for Tuesday night and wendesday
night, and maybe some Mountain Valley 40s in the highest
locations. No organized convection in the long term, less some
isolated mountain activity that may develop Friday/Saturday.
Aviation /07z Saturday through Wednesday/...
as of 115 am Saturday...
Patchy fog is starting to develop across the area this evening.
Expect brief MVFR and IFR conditions in fog. Otherwise, VFR
conditions across much of the area with light surface winds,
with a gradual return to VFR area wide after 13z.
Forecast confidence and alternate scenarios through 06z Sunday...
Forecast confidence: high.
Alternate scenarios: more widespread fog/stratus could develop
than forecast in the early Saturday morning hours.
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 Sat 07/20/19
UTC 1hrly 06 07 08 09 10 11 12 13 14 15 16 17
EDT 1hrly 02 03 04 05 06 07 08 09 10 11 12 13
crw consistency h h h h M l h h h h h h
heights consistency h h M l l l l h h h h h
bkw consistency h h h h M M h h h h h h
ekn consistency h h M l l l M M M M h h
pkb consistency h h h M M M M h h h h h
ckb consistency h h h h h h h h h h h h
After 06z Sunday...
late night/early morning IFR possible near river valleys on
WV...excessive heat warning until 8 PM EDT this evening for
Heat advisory until 8 PM EDT this evening for wvz024>026-
Ohio...excessive heat warning until 8 PM EDT this evening for ohz066-
Kentucky...excessive heat warning until 8 PM EDT this evening for
Virginia...heat advisory until 8 PM EDT this evening for vaz003-004.