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Area forecast discussion...updated 
National Weather Service Jackson Kentucky
355 am EDT Thursday Oct 2 2014

Short term...(today through friday)
issued at 355 am EDT Thursday Oct 2 2014

07z surface analysis shows high pressure still affecting the eastern
half of the Ohio Valley...though it is retreating off to the east. So
far this has been enough to keep the skies mostly clear over east
Kentucky with just a small area of SC at 5k feet spotted just north
of jkl. Despite the good radiational cooling and a decent ridge to
valley split the fog has not been as thick in the valleys and
elsewhere as it has the past few nights. Do expect some increase
toward dawn with patchy dense possible in the deeper valleys.
Readings range from the low to middle 60s on the ridges to the middle 50s
in the valleys while winds remain light and variable.

The models are in good agreement aloft with the major transition
that will take place during the latter part of the short term
forecast. They all depict a sharp trough digging through the middle
Mississippi Valley and into the Ohio Valley on Friday. A lead
shortwave/portion of this trough moves through east Kentucky early
Friday with the core of the unseasonably deep trough passing plowing
into our area later Friday. Ahead of this...moderate ridging will be
shunted out the Ohio Valley today and tonight. Given the model
agreement have followed the higher resolution nam12 for forecast
specifics along with some added blending from the latest European model (ecmwf).

Sensible weather will feature what could be the warm season/S last
hurrah as warmth is pumped over Kentucky today ahead of a significant
frontal passage. The front will get close to the area later tonight
with showers and a few thunderstorms a good bet. The initial front
then crosses east Kentucky early Friday with showers and possible
thunderstorms lingering through the day in response to additional middle
level energy and secondary boundaries moving through the southern
Ohio Valley. Cannot rule out a strong storm or two on Friday given
the healthy wind field that will be in place...though low instability
will likely limit their development. In general...expect around a
half an inch of rain with this system and cold air in its wake late
Friday.

Used the consshort as a starting point for the T/TD/wind grids
through the first 18-24 hours of the forecast and the superblend
there after. Made some minor adjustment to temperatures tonight
keeping them up on the ridge while allowing the eastern valleys to
briefly decouple before the convection moves in. As for probability of precipitation...ended
up pretty similar to a blend of the MOS guidance through the period.

Long term...(friday night through wednesday)
issued at 340 am EDT Thursday Oct 2 2014

..a cold weekend on tap...

At the start of the period...the cold front will be exiting eastern
Kentucky with strong cold air advection kicking into full gear Friday night.
Temperatures will tumble through the night...eventually falling into
the low to middle 40s by daybreak Saturday. While precipitation
chances will diminish through the night...a few showers or sprinkles
could linger through the night as westerly upslope flow...combined
with shallow low level moisture may keep the activity going a bit
longer than models are anticipating. Have also beefed up sky
cover...especially into Saturday. 00z European model (ecmwf) actually has a fairly
vigorous shortwave dropping across the area on Saturday...and given
the strong trough...cannot discount this possibility. Thus...plan to
keep some sprinkles in the forecast into Saturday evening. Wouldn't
be surprised to actually see a few showers as upslope flow continues
through this time. However...at this time...model support is lacking
for any showers on Saturday. Not sure we will see much sun through
the day Saturday as the influence of the trough may keep the cloud
cover held in over the region. However...models look to be handling
the sky cover very poorly. Regardless...cold air advection alone will keep highs in
the low to middle 50s...if not lower than this. It certainly will not
be a pleasant day...especially with a blustery west wind...putting
even more of a chill into the air.

Saturday night remains very uncertain at this time. If clouds hold
into Saturday night...they may act to insulate the area and keep
temperatures from falling off well into the 30s. However...if we
clear...some low to middle 30 readings may be possible. However...given
the thermal ridge is still upstream by Sunday morning...its more
likely we keep some clouds around...and thus...limiting the frost
potential. However...as mentioned...since models are trying to clear
things out...they are generally colder. Thus...plan to stay above
model guidance with lows for now given the pattern. In fact...00z
European model (ecmwf) brings another shortwave across the area Saturday
night...supporting more cloud cover.



&&

Aviation...(for the 06z tafs through 06z Thursday night)
issued at 215 am EDT Thursday Oct 2 2014

Mostly clear skies and light winds should promote the development of
fog in the deeper valleys of east Kentucky during the remainder of
the night. The fog may impact the lower elevation taf sites...such
as sme and loz...towards dawn. In fact...loz already is showing MVFR
fog despite a 2 degree dewpoint spread. Expect them to be up and down
through the night. Elsewhere...except for jkl...a brief period of
MVFR fog will be possible in the early morning hours of Thursday.
Otherwise...VFR conditions will prevail through 06z Friday...though a
lower deck of clouds...around 4k feet...is expected to develop from
west to east later Thursday night ahead of an approaching cold front.
The main impacts from front this will take place after this taf
cycle with low level wind shear a potential issue from 06 to 12z Friday. Winds will
be light and variable through the day Thursday before picking up from
the south at near 10 kts later that evening.

&&

Jkl watches/warnings/advisories...
none.
&&

$$

Short term...greif
long term...kas
aviation...greif

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