908 
FXUS63 KLMK 282328
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
728 PM EDT Thu Mar 28 2019

...Updated Aviation Discussion...

.Short Term...(This evening through Friday)
Issued at 300 PM EDT Thu Mar 28 2019

Southern Indiana and central Kentucky are south of the jet stream 
which is near the Canadian border. Over the Ohio Valley, mid-level 
flow is weak and un-amplified. At the surface, high pressure sits 
over the southeastern United States, and a low pressure center sits 
over the panhandle of Oklahoma. A cold front extended from this low 
to the northeast. Ahead of the cold front, moist flow from the Gulf 
of Mexico flows north. Surface convergence will cause rain showers 
that will advance into southern Indiana tonight after midnight. With 
dewpoints in the 30s a lot of dry air is in place that any rain 
showers will have to over come. With so much dry air in place, 
rainfall totals of a 0.1" and less are expected. Low temperatures 
should be mild tonight staying in the mid 50s with a southern wind 
and cloud cover.

Tomorrow, the same conditions continue as the cold front inches 
closer from the west. Rain chances in the afternoon will decrease
in south central Kentucky. Highs will make it into the 60s with 
the warmer of those temperatures to the south.

.Long Term...(Friday night through Thursday)
Issued at 300 PM EDT Thu Mar 28 2019

Friday Night - Saturday Night...

A surface low moving out of the eastern Plains is expected to ride 
along an initially stalled frontal boundary just to the north of 
the CWA Friday night. This feature is expected to move to the 
eastern Great Lakes by midday Saturday, which will lift the initial 
stalled frontal boundary north as a warm front early in the day then 
drag a secondary and strong cold front through the area later 
Saturday ahead of a strong shortwave trough axis.

The aforementioned synoptic setup will lead to light showers 
associated with isentropic lift mainly across our northern CWA along 
the stalled frontal boundary. Expect a mild overnight given decent 
southerly flow, and cloud cover. Most lows will only drop to the mid 
50s. The warm sector becomes better established on Saturday over the 
area, with gusty SW winds and temps warming just above normal into 
the 60s in the warm sector. Widespread rain and embedded 
thunderstorms are then possible through Saturday ahead of the cold 
front and sharpening shortwave trough axis where most amounts will 
total in the 0.5"-1" range across the region. Can't rule out a 
narrow axis of weak surface based instability on Saturday, however 
severe potential looks low as the best chances would be south and 
west of the CWA. Will keep an eye on instability trends and the 
chance for a stronger storm or two on Saturday. Otherwise, the main 
threats will be brief heavy rainfall, a few cloud to ground lightning 
strikes, and perhaps some gusty winds.

The cold front passes through later Saturday afternoon and evening, 
with precipitation ending from W to E as this occurs. Temperatures 
will fall off pretty dramatically behind the cold front, and should 
be in the 30s by dawn on Sunday. At this point, it looks close with 
regard to cold air catching up to the back side of any lingering 
precipitation chances, but will lean things being dry by the time 
cold air arrives to support anything other than rain.

Sunday - Thursday...

...Freeze Potential Sunday Night/Growing Season Has Progressed In 
Areas of Kentucky...

Strong Canadian surface high pressure and dry NW flow aloft will 
dominate the Sunday and early week time frame, bringing dry and 
cooler (below normal temps) conditions to the region. In fact, there 
is concern for a fairly hard freeze Sunday night/Monday morning as 
temps drop into the upper 20s. Will likely be starting up 
frost/freeze wording as UK Ag informed us that the growing season 
has progressed in southern KY. Future headlines may be needed for 
Sunday night.

The upper pattern will transition to a zonal and then deeper 
SW flow pattern by mid to late week, resulting in a steady warm up 
through that time. There is some signal of a weak system passing to 
our south on Tuesday, however not too confident in this feature 
given model variability. Highs are expected to be above normal in 
the 60s and 70s by Wednesday and Thursday.

&&

.Aviation...(00Z TAF Issuance)
Updated at 728 PM EDT Thu Mar 28 2019

A quasi-stationary front reaching from the St Lawrence Valley to the 
southern Plains will be a focal point for showers during this TAF 
period.  HNB and SDF will stand the best chances of rain and MVFR 
vis/cig, especially as a small wave moves overhead late tonight and 
another approaches Friday afternoon.

Low level winds will increase off the surface tonight ahead of the 
boundary, coming in from the SSW around 30-35kt at 2k' producing 
borderline LLWS.

&&

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

$$

Short Term...KDW
Long Term...BJS
Aviation...13