Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 191107
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
607 AM EST Mon Feb 19 2018

.Short Term...(Today through Tuesday)
Issued at 236 AM EST Mon Feb 19 2018

At the surface the short term will be spent sitting between high
pressure off the East Coast ridging back into the southeast United
States and low pressure from the southern Rockies to the Great
Lakes. The upper pattern will become increasingly meridional with a
trough digging into the West and a ridge pumping up over the East.
The ridging will keep upper vort energy and lower surface pressures
to our west and north, and, as a result, that`s where most of the
shower activity will be as well. The best chance for showers here
will be during the morning hours today as a warm front lifts
northward across the region.

Deep southwesterly flow will bring very moist, warm air northward.
Surface winds will gust to 30-35mph this afternoon and Tuesday
afternoon, with temperatures peaking in the 70s both days. Didn`t go
quite as robust with the temperatures tomorrow as the GFS did since
clouds and wet ground may help to temper things a bit, especially
with the still relatively low sun angle in February. Nevertheless, a
few spots touching 80 isn`t entirely out of the question and has
been advertised by the models for several days now. Went on the
warm side of guidance for lows tonight in the 60s.

.Long Term...(Tuesday night through Sunday)
Issued at 250 AM EST Mon Feb 19 2018

...Significant Rainfall Possible This Week and Into the Weekend...

The trough west/ridge east pattern will stay in place through this
weekend, though it will start to flatten late in the week. The main
corridor of heavy rains will be from Texas to the eastern Great
Lakes, with frequent waves of showers moving along that pathway in
the static pattern.

The mean of the GEFS plumes is showing three inches of rain during
the Wednesday-Sunday time period. The operational run of the GFS is
close to the mean in central Kentucky but is a very wet outlier in
southern Indiana. NAEFS output is closer to 4 inches, and the Euro
is generally in the 3 to 5 inch range. GEFS mean and GFS are also
generally in the 3 to 5 inch range if the wet anomaly over southern
Indiana is taken as being too high. An amount of 3-5" is also in
agreement with the latest WPC data as of this writing.

There may be enough instability present for a few rumbles of thunder
Wednesday, Friday, and Saturday, primarily in Kentucky.

Went warm for low temperatures south of the Ohio River Tuesday
night, with the Lake Cumberland region possibly not falling below
the middle 60s. No cold weather is in the picture throughout the
long term period, with lows most nights near or above the normal
highs for this time of year.

&&

.Aviation...(12Z TAF Issuance)
Issued at 606 AM EST Mon Feb 19 2018

A warm front will lift through the area today. North of it, fuel
alternate MVFR ceilings will persist with the possibility of brief
drops into IFR at BWG and HNB. Scattered showers will brush SDF and
HNB through about 14z. Once the front passes north of the TAF sites,
expect improving conditions as ceilings lift into VFR range.
South/southwest winds will pick up this afternoon with gusts 25 kts
likely. A strong low-level jet will lead to another round of LLWS
later this evening. Expect 2000 ft winds to be out of the southwest
45 to near 50 kts.

&&

.Hydrology...
Issued at 304 AM EST Mon Feb 19 2018

Minor flooding is already occurring on the Ohio River at Tell City
and should commence tonight at Cannelton and McAlpine Upper. The
Rolling Fork River near Boston is slightly above flood stage at the
time of this writing, but being a smaller stream and with only some
light rain showers in the area today, it should fall below flood
stage this morning.

In general, many other river forecast points in southern Indiana and
central Kentucky are forecast to go into minor flood. Depending on
the location of the heaviest rainfall later this week, some rivers
could reach moderate flood stage. Confidence in minor flooding is
high, and confidence in moderate flooding is medium. If rainfall
amounts are on the high side of the current forecast, the Ohio River
could approach moderate flood levels from Louisville downstream.
Looking at GEFS and NAEFS data, there is, as of right now, a 50-60%
chance of McAlpine Upper getting to between 29 and 30 feet this
weekend. Of course, that is *highly* dependent on how much rain
actually falls in the basin over the next several days. Just
something to keep an eye on for now.

The main risk for heavy rainfall across southern Indiana and central
Kentucky will be from Wednesday into the weekend. Multiple rounds of
moderate to heavy rainfall are possible in this time frame. Rainfall
amounts exceeding 3 to 5 inches are possible. This would exacerbate
flooding problems in low-lying areas and near rivers and creeks.
Stay tuned to the latest rainfall and river forecasts in the coming
days since the flood forecast will depend strongly on just where the
axis of heaviest rain sets up.

&&

.Climate...
Issued at 318 AM EST Mon Feb 19 2018

Record warm temperatures are possible today and Tuesday. Below are
the daily record high temperature records for 2/19 and 2/20 and the
all-time February high temperature records, which may be in jeopardy
for some locations tomorrow.

        Mon 2/19        Tues 2/20       Feb All-Time
SDF     74 (1939)       76 (2016)       81 (2/24/2017)
LEX     75 (1939)       72 (2016*)      80 (2/23/1996)
BWG     73 (1994*)      76 (2017)       83 (2/28/1918)
FFT     75 (1939)       73 (2016)       80 (2/24/2017 & 2/10/1932)

Record warm lows are expected on Tuesday. Here are the current
records:

SDF     55 (1994)
LEX     54 (1994)
BWG     55 (1994)

* and previous years

&&

.LMK WATCHES/WARNINGS/ADVISORIES...
IN...None.
KY...None.
&&

$$

Short Term...13
Long Term...13
Aviation...ZT
Hydrology...13
Climate...13


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