Scientific Forecaster Discussion
fxus61 krlx 220651
Area forecast discussion
National Weather Service Charleston WV
251 am EDT sun Sep 22 2019
very warm and mainly dry weather on Sunday. Cold front on
Monday, followed by high pressure. Weak front Thursday.
Near term /through tonight/...
as of 200 am Sunday...
Forecast on track, with River Valley fog beginning to form.
As of 1025 PM Saturday...
Minor temperature edits. Otherwise, quiet this evening.
As of 730 PM Saturday...
A few showers in central Ohio may clip Perry County, so added
slights up there for the next two hours. Cleared the skies
further south as far as other changes go for this update.
As of 200 PM Saturday...
A shortwave trough undercutting the upper level ridge has
contributed to isolated showers and thunderstorms across the
Ohio Valley this afternoon. Latest radar sampling places showers
across the northern periphery of the forecast area, lining up
well with hi-res model guidance for the afternoon timeframe.
Given this mindset, the best forcing and moisture advection will
press north and eastward by this evening, leaving central
Appalachia quiet and dry around or just after sunset.
The ridge will regain dominance over the area late tonight,
rounding out the weekend on a warm and dry note. The overnight
period will once again feature River Valley fog, beginning over
the northeast WV mountains then slithering further westward,
potentially as far west as the Charleston Metro area early
Sunday morning. This will then give way to a warmer than average
afternoon, with highs reaching the upper 80s across The
Lowlands under ample sunshine.
Pressure gradient will be on the increase in response to an
approaching cold front towards the end of near term period,
however the strongest winds will likely stay out of the rlx County Warning Area
as the boundary weakens upon arrival on Monday.
Short term /Monday through Wednesday night/...
as of 238 am Sunday...
Cold front crosses Monday with models showing a couple thin
bands of showers and perhaps a thundershower. Surface high
builds in for Tuesday as S/W trof axis shifts east. Upper level
flow flattens Wednesday with some upper level energy perhaps
allowing for a few showers late Wednesday night.
Temperatures return to more seasonable levels behind the front
Tuesday, but not quite as cool during the day as MOS suggests
given the prolonged dry spell and resultant soil moisture
profile. Low level warm air advection Wednesday will likely push temperatures
back above normal.
Long term /Thursday through Saturday/...
as of 242 am Sunday...
Another front is slated long about Thursday but given the nearly
zonal flow and weak overall flow, think rain chances will be
quite low. Upper level ridging is progged to build along the
southeast coast to round out the work week, retrograding west a
bit over the weekend. The end result is a continuation of dry
conditions as temperatures return to well above normal into
perhaps next week. This will exacerbate the drought situation,
especially across southeastern WV where flash drought conditions
are most pronounced.
Aviation /07z Sunday through Thursday/...
as of 200 am Sunday...
Light low level flow and a dearth of cloud will allow more River
Valley fog to form overnight, compared with recent nights.
Visibility at ekn and even pkb can drop to IFR during the first
hour of the forecast, by 07z, with IFR developing ckb 08z-09z,
and late at crw, 10z or just before dawn.
IFR to vlifr fog will lift briefly into stratus by 12z and then
thin out altogether by 13z. A VFR day is expected Sunday with a
very warm afternoon and a few cu.
Light south to calm flow overnight will become light southwest
on Sunday, and then light south Sunday night. Light southwest
flow aloft overnight and Sunday will become moderate southwest
Sunday night. This will keep valley fog from forming Sunday
Forecast confidence and alternate scenarios through 06z Monday...
Forecast confidence: medium.
Alternate scenarios: very low consistency in the guidance on
fog development overnight.
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 sun 09/22/19
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 M l l l l l M h h h h
heights consistency h h h h M h h h h h h h
bkw consistency h h h M M M h h h h h h
ekn consistency l l l M M M M l h h h h
pkb consistency h M l l l l l h h h h h
ckb consistency h h M l l l h h h h h h
After 06z Monday...
IFR or worse along the mountains overnight Monday night in the
wake of a weak cold front.