Area Forecast Discussion
Issued by NWS Jackson, KY

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259
FXUS63 KJKL 240140
AFDJKL

Area Forecast Discussion
National Weather Service Jackson KY
940 PM EDT SAT JUL 23 2016

.UPDATE...
Issued at 940 PM EDT SAT JUL 23 2016

WSR-88D radar showing all the showers and thunderstorms have died
off this evening. Therefore dropped these out of the GRIDS/HWO/ZFP.
Updated grids to reflect latest obs and trends with respect to
temps/dews/winds. Otherwise no major changes needed this update.

UPDATE Issued at 544 PM EDT SAT JUL 23 2016

WSR-88D radar continues to show much of the deeper convection
reside nearer the TN/VA border this afternoon. Otherwise a few
more pin prick showers have developed further north but have
generally died out as quick as they come up. The best cluster of
storms resides in Letcher and southern Knott county this hour. A
outflow is emanating in a arc like fashion from these storms, and
could be enough lift to spark additional storms in an area of
cloud streets located near by. Given there is no flow aloft or
synoptic lifting these outflows and orographic lift will be areas
that stand the best chance for convection. Generally thinking that
will be around Hal Rogers Parkway and south.

&&

.SHORT TERM...(This evening through Sunday night)
Issued at 305 PM EDT SAT JUL 23 2016

Isolated convection this afternoon has been confined to near the
TN border apparently in association with remnant boundary from
yesterday`s convection. Also isolated convection being noted in
association with higher terrain near the VA border. With steering
flow very weak any convection this evening will be very slow
moving, so will once again need to monitor for locally heavy
rain. Current indications are convection should diminish fairly
quickly after sunset.

For Sunday, it looks like mean layer moisture may be a little less
than today and 850 mb temperatures slightly warmer, thus allowing
for slightly higher maximum temperatures. Forecast for Sunday is
mostly in the lower 90s with heat indices still around 100. Thus
still not reaching heat advisory criteria for our area. Will
still highlight the heat index values in the HWO. Any convection
on Sunday should have even less coverage than today, but an
isolated thunderstorm will still be possible.

.LONG TERM...(Monday through Saturday)
Issued at 305 PM EDT SAT JUL 23 2016

Morning runs are showing quite good agreement and continuity with
mid/upper level features. The operation gfs/ecmwf solutions do
diverge somewhat beyond Thursday but overall trends are
consistent. Broad, roughly zonal flow gradually amplifies with
time across the CONUS resulting in ridging over the west coast and
across the east Atlantic. A mean trough takes shape over the Upper
Mid-West and Great Lake Region.

Our area will lie on the southern periphery of an active northern
stream, with a few weak disturbances and a couple more significant
short waves eventually digging out a trough across the eastern
CONUS. Consequently, sensible weather will include at least
scattered showers and thunderstorms through the bulk of the forecast
window. The best chance of rainfall will come early next week as a
cold frontal boundary drops southward to the Ohio River by late
Monday. This boundary becomes quasi-stationary and will act as a
focus for additional shower and thunderstorm activity through
Wednesday. What`s left of the boundary lifts northward by early
Thursday. Additional weak disturbances drop into the region from the
northwest ahead of a more significant trough taking aim for our
area by the following weekend.

The loss of mid and upper level ridging combined with daily
convection will help keep our high temperatures close to normal for
this time of the year, generally in lower to mid 80s. But with dew
points hovering around the 70 degree mark, our weather will remain
quite muggy. Likewise overnight lows will be warm, running a little
above normals in the upper 60s to near 70.

&&

.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
ISSUED AT 740 PM EDT SAT JUL 23 2016

Sites are starting the TAF period VFR with only some scattered CU
and higher clouds. Did opt to add some VCSH at SME/LOZ with some
cells nearer those sites. The question tonight is if any of the
sites will see VIS restrictions due to fog. do think the unusual
valley fog will be in place toward dawn, but only went for fog at
SME right now. The reason for not going with persistence is that
we really have not seen the amounts of rain we saw at many of the
sites yesterday. Overall once again Sunday looks similar to today
with more in the way of isolated convection in the far south.
right now kept this out of the TAFs given the lower confidence
based on some of the mesoscale models. Winds will remain light
through the period, but you may see brief gusts at JKL/SJS due to
a weak outflow tracking NW from earlier convection.

&&

.JKL Watches/Warnings/Advisories...
None.
&&

$$

UPDATE...DJ
SHORT TERM...SBH
LONG TERM...RAY
AVIATION...DJ



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