Area Forecast Discussion
Issued by NWS Louisville, KY

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649
FXUS63 KLMK 182121
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
421 PM EST Sun Feb 18 2018

...Added Hydro Discussion Section...

.Short Term...(This evening through Monday night)
Issued at 330 PM EST Sun Feb 18 2018

Progressive high pressure was centered near the Mid-Atlantic coast
this afternoon, and sfc winds were out of the southeast.
Temperatures have risen into the low to mid 50s thus far under
plenty of sun today. Coverage of cirrus will continue to increase
out of the WSW this afternoon and evening.

Low temperatures will likely occur between 00-05z tonight, just
before scattered precip and thicker cloud cover lift north into the
region. A warm front will lift through the region this evening and
overnight, bringing some light rain chances and rising temperatures
after midnight. Temperatures likely won`t drop below the mid 40s to
low 50s late this evening.

Hi-res models suggest an area of showers is likely to move ENE
across areas south of the WK/BG parkways in the 03-06z time frame.
Scattered to numerous showers will then move north through northern
KY and southern IN between 06-15z. The rain won`t last all that long
in any one spot, and amounts will be limited to 0.15 inches or less.
The rest of Monday will feature mainly dry weather, with heavier
showers well to our north.

Dry conditions and a stout southerly breeze will boost afternoon
highs into the low to mid 70s. Daily record highs could be in
jeopardy at the primary climate stations. Gusts to 25-30 mph are
likely out of the south. Monday night will remain breezy and very
mild by February standards. Lows in the low to mid 60s are forecast.

.Long Term...(Tuesday through Sunday)
Issued at 345 PM EST Sun Feb 18 2018

...Significant Rainfall Possible Later This Week...

A highly anomalous weather pattern is still poised to set up across
the lower Ohio Valley this week bringing threats for heavy rain,
river flooding, and potentially record warm temperatures to parts of
Kentucky and southern Indiana.

The long term portion of the forecast will feature a strong upper
level ridge over the southwestern Atlantic. This will be a very
persistent feature, along with a continuously reinforcing Western
U.S. trough. At this time, Tuesday still looks to be a dry, warm,
and windy day. An axis of heavy rainfall will likely set up across
parts of Missouri and Illinois, where the robust LLJ/moisture
transport will be located. The latest guidance has eased off low-
level thicknesses and temps just a tad, but continuing to feature
highs around 80. Gusts over 30 mph are likely Tuesday afternoon.

Beginning early Wednesday, the chance for rainfall ramps back up as
the front sags toward the Ohio River. The heavy rainfall potential
will stay north of the Ohio River through 12z Wednesday, with
widespread moderate to heavy rainfall likely during the day into
Wednesday night. 1 to 2 inches of rain are possible through 12z
Thursday. This will result in additional rises on smaller creeks and
certainly prolong the rise on the main stem of the Ohio. Minor
flooding is likely at multiple river forecast points this week, and
moderate flooding is possible.

From Thursday onward, confidence is only medium. But the latest
suite of model guidance features a pattern that could dump copious
amounts of rainfall across the forecast area. The risk for flooding
certainly increases Thursday into the weekend. A stationary boundary
waffling over the OH/TN valleys will be the focus for multiple
rounds of moderate to heavy rainfall. The latest GEFS mean features
3 to 4 inches of rainfall through Saturday. There is some potential
for amounts over 4 inches, particularly west of I-65 and across
southern Indiana. Folks should stay abreast of the latest rainfall
and river forecasts through the coming week.

&&

.Aviation...(18Z TAF Issuance)
Issued at 1240 PM EST Sun Feb 18 2018

A warm front will move north through the Ohio Valley tonight
bringing light rain showers to the region from roughly 4-15Z this
TAF period. Also accompanying the front will be a strong LLJ and
MVFR conditions below 2 kft.  IFR looks likely at HNB between 9-15Z.
The LLJ will increase to 40-45 kts from the SW overnight.  With sfc
winds primarily from the south between 7-10 kts and a decent low
level inversion, LLWS looks likely and have added it to all TAF
sites from 3Z-15Z give or take a few hours depending on the site.
While the LLJ will remain strong through the afternoon hours
tomorrow, better mixing in low levels will cause sfc winds to shift
to the SSW and gust to around 20-25 kts eliminating the LLWS mention
in the TAFs after 15-16Z.


&&

.Hydrology...
Issued at 200 PM EST Sun Feb 18 2018

Minor flooding is already occurring on the Ohio River at Tell City
as well as the Rolling Fork River near Boston. The Ohio River is
also forecast to reach minor flood stage at McAlpine Upper/Lower by
midweek. A Flood Warning is also in effect for the Ohio River at
Cannelton Lock and Dam.

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.

The main risk for heavy rainfall across southern Indiana and central
Kentucky will be from Wednesday into next weekend.
Multiple rounds of moderate to heavy rainfall are possible in this
time frame. Rainfall amounts exceeding 3 inches are possible, with
higher totals possible west of I-65 and across southern Indiana.
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.

&&

.Climate...
Issued at 230 AM EST Sun Feb 18 2018

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

        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)

* and previous years

&&

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

$$

Short Term...EBW
Long Term...EBW
Aviation...AMS
Hydrology...EBW
Climate...ZT



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