Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 211133
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
633 AM EST Tue Feb 21 2017

.Short Term...(Today through Wednesday)
Issued at 300 AM EST Tue Feb 21 2017

Early morning observations reveal partly to mostly cloudy skies
across the region.  Temperatures were generally in the mid to upper
50s though some outlying locations had dipped into the upper 40s.
Overall weather looks to be quiet for the remainder of the overnight
period.  Overnight lows should drop into the upper 40s to the lower
50s.

For today, long meridional trough axis is expected to move eastward
today.  The southern end of this trough axis is expected to close
off into an upper low which then will roll eastward across the
southern states.  Ahead of this upper level low, decent northward
transport of moisture will be pulled northward into the region.  In
sensible terms, plenty of cloud cover will be seen today with some
scattered showers developing in the afternoon hours.  Best coverage
today looks to be across southern Kentucky with precipitation
increasing in coverage across the area as we head into tonight.
Despite the cloud cover, a deep southerly flow will transport mild
air into the region and highs look to warm into the upper 60s.  A
few spots could top out at 70.

For tonight, plenty of cloud cover will remain early in the period.
Widespread light to moderate rain showers will be found across the
region this evening.  In general, the highest chances look to be
across much of Kentucky, with lesser chances across our far
northwestern areas.  Rainfall amounts continue to look light with
most areas seeing less than one quarter of an inch.

As the upper low moves off to the east/southeast late tonight, some
partial clearing will take place. Quite a bit of the data for
tonight suggests that fog may develop across central/southern
Indiana back into western Kentucky.  The SREF means agree with this,
though some individual ensemble members are a bit more aggressive in
developing fog as far east as the I-65 corridor late tonight.  Based
on the data, we have added in some patchy fog across the
northwestern 1/2 of the forecast area.  Lows tonight will drop into
the upper 40s to the lower 50s.

As we move into Wednesday, the upper low across the southeastern US
will move southeast and move across the Florida peninsula.  Some
ridging will build into the region from the west.  Clouds will
likely be socked in across the region early Wednesday with clearing
taking place throughout the day.  Temperatures will probably exhibit
a gradient across the region.  Highs in the Bluegrass region will
likely warm into the mid-upper 60s, with upper 60s to the lower 70s
confined to areas west of I-65.

.Long Term...(Wednesday night through Monday)
Issued at 321 AM EST Tue Feb 21 2017

Main focus in the long term remains fixed on a strong storm system
that is expected to impact the region late Friday and early Saturday.

The early part of the extended period (Thursday and into early
Friday) will be unseasonably warm with highs on Thursday reaching
the lower 70s in the northern half and perhaps the mid-upper 70s
across southern Kentucky.  A weak weather system will likely swing
through the region early Thursday producing a few showers as a warm
front surges through the region.  With the front surging northward,
we`re likely going to be stuck in the warm and drier warm sector
Thursday night and into Friday.  Lows Thursday night will be mild
with readings only dropping into the mid-upper 50s.  A strong
southwest flow will result in mild and breezy conditions for Friday.
Afternoon temperatures will likely surge into the lower-mid 70s
across the entire region.  While cloud cover is expected to be
fairly high, if more clearing develops than currently forecast, high
temps may be under-forecast here and readings could warm into the
mid-upper 70s.

As we head into late Friday, a strong cold front and associated
upper level trough axis will move toward the Ohio Valley while a
deepening surface low will race from the Plains into the Great
Lakes.  Showers and thunderstorms will likely develop out ahead of
this feature and push eastward into our region Friday night and
early Saturday.

Overall convective strength still looks rather strong for this time
frame.  A good northward surge of quality moisture combined with
cooling aloft will result in steepening lapse rates and increasing
instability.  Bulk shear values remain quite elevated across the
region suggesting damaging winds as the primary severe weather
hazard.

With the cold front passing through the region overnight Friday, a
surge of colder air will arrive into the region for Saturday.
Temperatures for Saturday will be some 20-25 degrees cooler than what
we see on Friday with highs mainly in the lower 40s across southern
Indiana and upper 40s across central and southern Kentucky.  High
pressure will cross the region Saturday night and that should allow
temperatures to cool into the mid-upper 20s by Sunday morning. Highs
Sunday will rebound slightly with readings warming into the upper
40s to around 50.

A fast moving, but weak system will push through the region Sunday
night and into early Monday.  The GFS continues to be more bullish
with the system than the drier Euro.  With temperatures falling into
the lower-mid 30s a wintry mix of rain/snow is possible as this
system moves through the region.  However, the cool spell will not
last all that long as the Sunday night system move east and a warm
front surges back to the north.  At this point, Monday looks to be
cloudy and showery as the warm front surges back to the north. Highs
by late Monday will likely warm into the mid-upper 50s with some 60s
possible across far southern KY.

&&

.Aviation...(12Z TAF Issuance)
Issued at 630 AM EST Tue Feb 21 2017

Moisture deepens today as a storm system moves across the Gulf
States. Expect VFR until then, however a gradually lowering upper
and mid deck will be noted. Winds will also be steady out of the S
or SSW around 10 mph, slightly higher at LEX

As we move toward the late afternoon and early evening, the
atmospheric column saturates enough to support scattered showers.
Will also mention MVFR ceilings and vis during this time. LEX will
have the best shot at the most persistent showers and lowest flight
categories. IFR ceilings/vis are not out of the question, but don`t
have enough confidence to mention at this time.

&&

.Climate...
Issued at 400 AM EST Tue Feb 21 2016

Record temperatures for the next few days.

Louisville:
Tue. Feb. 21 record warm low: 51 (1878)
Tue. Feb. 21 record high:     70 (1930*)
Wed. Feb. 22 record warm low: 61 (1922)
Wed. Feb. 22 record high:     71 (1992*)

Lexington:
Tue. Feb. 21 record warm low: 54 (1997)
Tue. Feb. 21 record high:     71 (1874)
Wed. Feb. 22 record warm low: 55 (1922)
Wed. Feb. 22 record high:     70 (1922)

Bowling Green:
Tue. Feb. 21 record warm low: 54 (1897)
Tue. Feb. 21 record high:     75 (1930*)
Wed. Feb. 22 record warm low: 55 (1961*)
Wed. Feb. 22 record high:     74 (1922)

Frankfort:
Tue. Feb. 21 record warm low: 47 (1906)
Tue. Feb. 21 record high: 72 (1997)
Wed. Feb. 22 record warm low: 49 (1935*)
Wed. Feb. 22 record high: 72 (1922)

* means most recent occurrence, record occurred in previous years as
  well

&&

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

$$

Short Term...MJ
Long Term....MJ
Aviation...BJS
Climate......BJS


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