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Area forecast discussion 
National Weather Service Louisville Kentucky
640 am EDT sun Apr 19 2015

..updated aviation discussion...

..Forecast update...
issued at 630 am EDT sun Apr 19 2015

Rain showers have increased quickly across the region over the last
hour. There is not much in the way of lightning with this activity
this morning, so removed the mention of thunder for the next few
hours. Instability should increase by mid morning, so will continue
to mention scattered thunderstorms from mid morning through the
afternoon. Otherwise the forecast is in fairly good shape.

Short term (now through monday)...
issued at 251 am sun April 19 2015

The weather will remain quite unsettled through the short term
period as multiple rounds of showers and storms will be possible.
The first round will bring the most widespread rain this morning
through early afternoon. A surface low currently over Arkansas will
move northeast through the day passing just to the northwest of the
forecast area. Scattered light showers are showing up on radar this
morning associated with isentropic lift ahead of the warm front that
will move north this morning. Showers are expected to increase in
intensity and coverage through the next few hours with widespread
rain showers and scattered thunderstorms continuing through the
morning as the warm front crosses the region.

There should be a bit of a break in the showers and storms early
this afternoon. Winds will increase in the warm sector this
afternoon both at the surface and aloft. Soundings continue to
indicate instability will develop later in the afternoon,
particularly if any breaks in the clouds are able to form. Scattered
showers and storms are expected to develop from mid afternoon and
continue until early evening. A few of the storms could become
strong to marginally severe this afternoon with isolated damaging
winds and hail. Outside of any thunderstorms, winds will be breezy
this afternoon with gusts to around 30 mph.

There will likely be another break in precipitation this evening
before another shortwave and its attendant surface low approach from
the west. This low will finally swing a cold front through the
region during the day on Monday. Scattered to numerous showers and
scattered thunderstorms will continue to be possible through the day
Monday. Temperatures on Monday will be tricky with the front moving
through. At this time they look to hold steady of fall a few degrees
through the afternoon hours.

Storm total rainfall will be in the one to one and a half inch range
with amounts up to two inches possible. The bulk of the rain will be
this morning through mid afternoon. Though widespread flooding
issues are not anticipated, some rises can be expected on smaller
streams, as well as ponding of water in low lying areas.

Long term (monday night through saturday)...
issued at 250 am EDT sun Apr 19 2015

We should be drying out Monday night as high pressure moves into the
deep south and as the broad low pressure area beginning to affect US
now heads off to the northeast. We will head into a period of
temperatures a little below normal for the rest of the long term, as
troughing aloft looks to persist.

As for the next chance for rain, the latest NAM and GFS both hint at
some precip along the Ohio River Tuesday afternoon, whereas our
ongoing forecast is dry. This precip looks to be in response to
moisture returning on the back side of the departing high pressure,
as it heads to the southeast U.S. Coast. The Euro and Gem both hold
off on this precip until Tuesday night or Wednesday, instead having
a cool front approaching the region be responsible for forcing the
showers. Will lean the latter direction, and keep rain chances to
Tuesday night/Wednesday.

After that precip, the next solid chance for rains looked like it
would come Friday with the 00z models yesterday, but now that threat
has shifted to Friday night/Saturday, once again as the models think
another system is getting organized over the Central Plains. Will
keep pops in the chance range given this uncertainty.

&&

Aviation (12z taf update)...
updated at 638 am EDT sun Apr 19 2015

Rain has increased across the region over the last hour or so.
Ceilings are still expected to lower through the morning, though it
is taking longer than previously forecast. Upstream observations
have dropped to MVFR with some IFR. Will continue to carry IFR cigs
at bwg and Lex for a period later this morning. Also pushed back the
timing for thunderstorms in the vicinity in the tafs as the activity this morning does not
have lightning in it so far. There will be two possible periods of
thunderstorms - one this morning and one later this afternoon. Winds
today will shift to southerly by early afternoon and then to
southwesterly by mid afternoon. Wind speeds will be sustained in the
10-15 knot range this afternoon with gusts up to 25 knots.

&&

Lmk watches/warnings/advisories...
Kentucky...none.
In...none.
&&

$$

Update.........Eer
short term.....Eer
long term......rjs
aviation.......eer

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