Area Forecast Discussion
Issued by NWS Jackson, KY

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FXUS63 KJKL 212346

National Weather Service Jackson KY
746 PM EDT Wed Jun 21 2017

Issued at 739 PM EDT WED JUN 21 2017

Forecast seems to be in good shape so far this evening. Did notice
that a bkn deck of high clouds is in place at JKL and according to
satellite across much of the CWA. Will go back and adjust cloud
cover upwards to account for this. Loaded in the latest
observations for temps, dew points, and winds to make sure the
near term forecast was on track with the current conditions. All
changes have been published and sent to NDFD/web, though will do
this again after adjusting cloud cover as well.


.SHORT TERM...(This evening through Thursday night)
Issued at 409 PM EDT WED JUN 21 2017

High pressure remains positioned across the mid-Mississippi
Valley at the surface and through the mid-levels, as Cindy moves
across the north central Gulf towards the Texas/Louisiana border.
Eastern Kentucky has enjoyed the last dry day for the rest of the
work week, with temperatures generally in the mid 80s, with dew
points mainly in the low to mid 60s.

The models are in pretty good agreement through the short term,
with high pressure holding sway through most of tonight across our
area. Higher dew points in place will keep lows milder tonight,
generally in the mid to upper 60s. Clouds will be on the increase
towards dawn, as moisture increases in response to a low level jet
ramping up across the lower Mississippi Valley. Showers, with
some thunderstorms possible, will move in across the area from
south to north on Thursday as the nose of the low level jet moves
through the region. Plenty of cloud cover and the precipitation
will keep highs down, generally in the upper 70s to lower 80s.

There may be somewhat of a lull in the activity Thursday night, as
the core of the low level jet passes by to the north, and we
essentially remain in a warm sector, as a baroclinic zone sets up
just to our northwest. POPs will ramp back towards dawn, as the
boundary drifts closer to us by that time, although depending on
the exact track of Cindy, there may wind up being a sharper
gradient in POPs than currently reflected in the forecast. Lows
will be soupy, generally in the upper 60s.

.LONG TERM...(Friday through Wednesday)
Issued at 337 PM EDT WED JUN 21 2017

The extended forecast begins on Friday with the subtropical ridge
still in place over the southeastern CONUS bringing tropical
moisture northward into Kentucky as the remnants of Tropical
System Cindy moves into the Mid MS Valley and then east into the
TN Valley. The latest run has brought the heaviest rainfall a bit
further north than the previous run into Kentucky. Thus will keep
QPF amounts from the super blend with a blend of the WPC amounts.
Consistency in the model runs continue to keep the heaviest
rainfall in the area Friday night with PWAT values well above 2
inches. So will continue to mention heavy rainfall Friday night in
the HWO with the more moderate rain beginning on Friday. In
addition to the heavy rainfall with the abundant moisture and
increased shear, a few strong storms can`t be ruled out for Friday
with some gusty winds being the main threat in addition to
flooding. This element is complicated based upon the amount of
forcing imposed by the cold front dropping south Friday as well.
The onset of some instability to the situation could set the stage
for a few severe storms as well. After this the heaviest rainfall
arrives Friday night with models coming into agreement that the
system will exit by Saturday evening.

After the amalgamation of the front and remnants of Cindy pass
through during the day on Saturday, brief ridging passes by for
Saturday night and into Sunday morning with the next wave pushing
into the area by Sunday afternoon. The pattern indicates a
continued strong southerly surge of Gulf moisture into the area.
Thankfully the upper level pattern continues to hint at a zonal
and progressive flow as the shortwave pushing through will quickly
exit by Monday afternoon. In addition, current model profiles
indicate little instability and will seem to lack the deep
convection for heavy rainfall keeping a more steady rainfall for
Sunday afternoon through Monday morning. This will be a welcomed
pattern as the rainfall over the first half of the weekend from
Cindy will likely leave many locations flooded or at least creeks
and streams running high. The extended forecast period will come
to an end By Tuesday night with ridging settling in once again
across Kentucky for Monday night through Tuesday night.


.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)

High pressure remains in control this evening, with daytime
cumulus clouds dissipating as we lose daytime heating. In return,
high clouds have taken hold across much of eastern KY as moisture
begins to surge in from the SW ahead of Tropical Storm Cindy. A
low level jet is expected to increase from the south and southwest
towards dawn Thursday, bringing lowering ceilings and eventually
showers and a few thunderstorms to the area during the day on
Thursday. Based on latest models, went MVFR CIGS at most of the
TAF sites during the afternoon, though given the uncertainty on
the timing and impacts of showers/thunderstorms at a given TAF
site, chose to leave VIS at P6SM. Both VIS and CIG will be
affected if any showers and thunderstorms do pass over a TAF site.
West southwest winds at generally 5 kts or less, will gradually
back to the south southwest later in the period.




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