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Area forecast discussion 
National Weather Service Jackson Kentucky
1109 PM EDT Friday Jul 29 2016

Update...
issued at 1109 PM EDT Friday Jul 29 2016

The update mainly blends obs into the overnight forecast grids.
With just spotty showers heading in from the west, the pop has
been placed at 20% overnight. Short range models would also
suggest spotty coverage.

Update issued at 859 PM EDT Friday Jul 29 2016

Precip has mostly died out in the jkl forecast area, but persists
upstream in central Kentucky and southern Ohio. It should be on an overall
decline this evening, but short range models still generate spotty
precip overnight. Will continue with low pops already in the
forecast.

&&

Short term...(this evening through Saturday night)
issued at 336 PM EDT Friday Jul 29 2016

The models are in good agreement with cyclonic flow aloft and
continuing to suppress the upper level ridging to the south. This
will interact with the nearby boundary to bring chances of storms
through the short term period. This afternoon WSR-88D showing
showers and thunderstorms are moving east mostly across areas
along and south of the mountain Parkway. Some of these storms will
bring locally heavy rain and gusty winds. These storms are
expected to spread east into the early evening hours. Hrrr has a
decent handle on the main area of precip across the southern half
of the County Warning Area. Therefore blended pops in that direction given the
reasonable timing. It does look like much of the convection will
be diurnally driven, but given the pattern keep isolated pops
through the night. Another issue that remains in question tonight
will be fog and how much we see. Right now will go with at least
patchy fog in the valleys but cloud cover could help mitigate some
locales.

Then another stormy day on tap for Saturday, as higher precipitable waters
remain in place and quasi stationary boundary remains near. Right
now once again going scattered coverage in the afternoon hours.
Not really favoring any certain model at this point and went
toward a blend approach at this point given the scattered
coverage. Once again expecting more in the way of diurnally driven
activity and therefore lessen the coverage once again on Saturday
evening. Temperatures through the short term period will run near
normal.

Long term...(sunday through friday)
issued at 435 PM EDT Friday Jul 29 2016

The models are in fairly good agreement aloft through the extended
portion of the forecast. They all depict a retreat of the Great
Lakes trough through the start of next week while strong mid level
ridging reloads over the Southern Plains and east through the deep
south/Tennessee Valley. As this happens, though, plenty of energy
will drift through the Ohio Valley from Sunday through Monday
before higher heights shunt it all off to the northeast,
temporarily. After this, the ridge does retreat to the southwest
a tad and subsequently allow for more ridge riding energy packets
to potentially target eastern Kentucky from Wednesday through
Friday, most clearly evident in the latest European model (ecmwf). Given the
general agreement, a model blend looks to be a reasonable place to
start for gridded forecast purposes.

Sensible weather will feature rounds of mainly diurnally enhanced
showers and thunderstorms through Monday. Heat will gradually
rebuild through the area for the start of the week with some 90
degree readings anticipated for the latter part of the forecast.
However, the worst of this round of heat will likely be tempered
by scattered convection from Wednesday to Friday. It looks like
the lowest pops will be from Monday night through Wednesday
morning as the core of the ridge is closest to our area and surface
high pressure builds in briefly from the northeast.

For the CR initialization: made some minor changes to mint and
hourly T each night with some terrain differences anticipated due
to radiational cooling in the valleys. Did make some mainly
diurnal adjustments to pops through the forecast period, as well.
The rest came in real good.

&&

Aviation...(for the 00z tafs through 00z Saturday evening)
issued at 859 PM EDT Friday Jul 29 2016

Convective precip affected most of the area during the afternoon
or early evening. This has left cooled air at the surface and high
relative humidity at the start of the night. Precip has mostly died out, but
persisted over central Kentucky and southern Ohio.

The main concerns will be the extent of fog development
tonight...and whether the area of precip to the west and north
will make it here. Think that there will be an overall decline in
precip as we head through the night, and confidence in anything
happening at a particular taf site is too low to warrant inclusion
of precip tonight. The stage is set for fog development, but the
extent of cloud cover will modulate the fog. Will call for
conditions to fall to at least IFR at all taf sites. However,
timing and just how low the visibility GOES is still somewhat
uncertain.

Fog and low clouds will dissipate on Saturday morning. A general
repeat of the convection cycle is expected during the day, with
heating causing showers and thunderstorms to percolate, mainly
during the afternoon and early evening. With uncertainty in timing
and location, the best that can be done at this point is too use
thunderstorms in the vicinity in tafs.

&&

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

$$

Update...hal
short term...dj
long term...greif
aviation...hal

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