Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 301130
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
730 AM EDT Sun Apr 30 2017

...Updated Climate Discussion...

.Forecast Update...
Issued at 642 AM EDT Sun Apr 30 2017

The area of rain to the west of the forecast area has been
persistently pushing east overnight. The forecast was updated to
increase pops along and west of I-65 this morning. The eastern edge
of this rain does appear to be weakening somewhat and think it may
eventually scatter out and lift to the north before the next round
moves in this afternoon. However, with models not handling the
ongoing precipitation well, confidence in the forecast is lower than
normal.

&&

.Short Term...(Today through Monday)
Issued at 321 AM EDT Sun Apr 30 2017

...Additional Flash Flooding and Severe Weather Possible Today...

The unsettled weather will continue through tonight ahead of a cold
front which will push through tomorrow and bring cooler and drier
weather. For today, the region will remain in the warm sector of a
low pressure system currently centered over northeastern OK. This
low pressure system will track northeast into the upper Midwest by
Monday morning.

Most of the region should remain dry today through at least the
first half of the afternoon. Though a few storms cannot be ruled out
this morning, mainly across southern IN and far west central KY,
coverage should be fairly isolated. This afternoon the region should
become moderately unstable. A shortwave crossing the region this
afternoon and evening should spark convection along and west of I-
65. There looks to then possibly be a break with a second wave of
showers and storms during the evening and overnight hours as the cold
front moves through. Though there is a lot of uncertainty, with
cyclonically curved hodographs and moderate instability and wind
shear, a few strong to severe storms will be possible. Large hail
and damaging winds are the main concerns, though a tornado cannot be
ruled out.

As we go into the overnight hours, soundings become very saturated.
Heavy rain will be a concern again. Will keep the Flash Flood Watch
in place as it is in the area where the most rain fell last night
and soils are very saturated. Will not adjust the timing on it, but
the biggest concern will be this evening into the overnight hours.
Rain should be ending on Monday morning with drier and cooler air
filtering in behind the cold front.

The other concern today will be the potential for some very gusty
winds. With decent mixing and stronger winds aloft, portions of
southwest central Kentucky look to get wind gusts up to around 40
mph this morning through the afternoon hours, so a Wind Advisory
will be issued for that region. Elsewhere, it looks like gusts will
peak a bit below criteria, so will hold off on issuing a Wind
Advisory for these areas for now. For Monday, winds will again be
quite breezy with gusts of 30-35 mph out of the west behind the cold
front.

.Long Term...(Monday night through Saturday)
Issued at 329 PM EDT Sat Apr 29 2017

Quieter weather is in store for Monday night through Tuesday evening
as high pressure builds in and quasi-zonal flow sets up aloft.
Temperatures will be much closer to normal for this time of year.

The dry weather will be short lived, however, as a shortwave
approaches late Tuesday night into Wednesday morning bringing
another round of rain and possibly a few thunderstorms. Thereafter
through the end of the week, a trough will develop and deepen across
the eastern CONUS. The models are still struggling even run to run
even in the same model with how this trough will develop and whether
it will become a closed low. Regardless, we look to have rounds of
showers off and on for the end of the week and into the weekend.
Where the cutoff/placement will be for each round of showers is
still in question and will highly depend on the evolution of the
upper level trough. Temperatures will be on the cooler side for the
end of the week with highs in the 60s and lows in the mid to upper
40s.

&&

.Aviation...(12Z TAF Issuance)
Issued at 644 AM EDT Sun Apr 30 2017

Secondary area of convection ahead of a MCV over IL should continue
to propagate eastward while dissipating.  The models have handled
this line rather poorly this morning.  The line is currently outflow
dominated and it appears that some showers may end up affect KBWG
for a time this morning.  Otherwise, no major changes to the
upcoming TAF period from the 30/06Z forecast.   Winds should
gradually increase this morning with sustained winds of 13-18kts
with occasional gusts in the 25-30kt range by late morning into the
afternoon hours.  Cold front will push in from the west later today
resulting in another round of convection.  Have tried to fine tune
the convection a little more with this TAF issuance.  Current
thinking is that convection will still hold off until after 01/00Z
at KSDF and KBWG and likely not impact KLEX until after 01/06Z.

&&

.Climate...
Issued at 333 AM EST Sun Apr 30 2017

Temperature and rainfall records for the weekend:

               4/30 Warm L  4/30 Record H
Louisville       70 (1899)    91 (1894)
Lexington        70 (1899)    91 (1942)
Bowling G.       68 (1899)    92 (1942*)
Frankfort        66 (1910)    91 (1942)

            4/30 Rainfall   5/1 Rainfall
Louisville   2.37" (1983)    2.34" (1983)
Lexington    3.21" (1909)    3.03" (1983)
Bowling G.   3.00" (1911)    4.75" (2010)
Frankfort    2.62" (1909)    1.58" (2010)
&&

.LMK WATCHES/WARNINGS/ADVISORIES...
IN...Flash Flood Watch through Monday morning for INZ076>079-083-084-
     089>092.

KY...Flash Flood Watch through Monday morning for KYZ023>025-030>033.

     Wind Advisory from 11 AM EDT /10 AM CDT/ this morning to 7 PM
     EDT /6 PM CDT/ this evening for KYZ023-024-026>028-061>063-
     070>076.

&&

$$

Update...EER
Short Term...EER
Long Term....EER
Aviation...MJ
Climate...EER/RJS


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