Scientific Forecaster Discussion
fxus61 krlx 200732
Area forecast discussion
National Weather Service Charleston WV
332 am EDT Fri Sep 20 2019
unseasonably warm and dry weather persists through the weekend.
Weak cold front crosses Monday into Monday night. High pressure
Tuesday and Wednesday.
Near term /through tonight/...
as of 330 am Friday...
Southerly low level flow continues across the area this period,
beneath upper level ridging with weak ripples moving through.
Weak early morning warm advection was producing patchy high
stratocu / low altocu, even an isolated shower, over portions of
the middle Ohio Valley. Cloud top warming should take care of
this later this morning, and the balance of the day will again
feature more sunshine than clouds, along with another very warm
afternoon, as upper level ridging builds slightly.
Clouds may increase a bit late overnight tonight in weak warm
advection again. However, with weaker flow, showers are not
expected. In the light flow, River Valley fog may return before
the increase in clouds, only to possibly dissipate as the
Went with bias corrected guidance for higher highs today, to
account for the dry soil. Central guidance was accepted for
lows tonight, but may eventually need raised depending on the
increase in cloud cover. Afternoon dew points needed adjusted
down a bit per mixing and dry soil.
Short term /Saturday through Monday night/...
as of 240 am Friday...
Upper level ridging takes hold for the weekend with dry
conditions continuing. Given the cool bias of late even with the
nbm, I elected to use the warmer ece for maxt both days as soil
moisture remains very low.
The northern peripheral of the ridge breaks down Monday with
the approach of an amplifying trof. The associated cold front
looks to cross early in the day with scattered showers.
Confidence on the overall coverage of showers is somewhat low
with many of the global models scant on moisture. The NAM seems
to be the outlier at this time with the bullish quantitative precipitation forecast depicted
given the lack of any significant moisture advection.
Long term /Tuesday through Thursday/...
as of 245 am Friday...
Cooler air and lower humidity will filter in behind the front
for Tuesday. This will be short-lived however, with warm air advection
boosting temperatures above normal once again as the S/W trof
passes to the east.
It should be noted that the overall dry pattern looks to
continue, perhaps well beyond the extended periods. This will
further exacerbate flash drought conditions across southern West
Aviation /07z Friday through Tuesday/...
as of 150 am Friday...
VFR with the exception of brief MVFR mist at ekn overnight into
Friday morning. Very dry conditions continue across the region,
together with low level winds, contribute to the lack of
Light southeast surface flow overnight will become light and
variable on Friday. Light to moderate south to southwest flow
aloft over the middle Ohio Valley and light south flow over the
central Appalachians overnight, will become light southwest
throughout the area on Friday.
Forecast confidence and alternate scenarios through 06z Saturday...
Forecast confidence: high.
Alternate scenarios: restrictions at ekn may not materialize.
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 Friday 09/20/19
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 h h h h h h h h
heights consistency h h h h h h h h h h h h
bkw consistency h h h h h h M h M M M h
ekn consistency h M l l l l l l h h M h
pkb consistency h h h h h h h h h h h h
ckb consistency h h h h h h h h h h h h
After 06z Saturday...
early morning River Valley fog possible each morning this