Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 191549

Area Forecast Discussion
National Weather Service Louisville KY
1149 AM EDT Thu Oct 19 2017

...Forecast Update...

.Forecast Update...
Issued at 1149 AM EDT Thu Oct 19 2017

No major forecast updates needed through this afternoon and evening.
Plan on a few passing cirrus, otherwise light southwest breezes will
prevail and highs will top out in the lower to middle 70s.


.Short Term...(Today through Friday)
Issued at 300 AM EDT Thu Oct 19 2017

The surface high was centered over Virginia early this morning, with
satellite imagery showing mostly clear conditions. A patch of cirrus
was spreading southeast over southern Kentucky. As seen on the GOES-
16 fog product, river valley fog development has been very limited
thus far. This is due to quite a bit more wind in the boundary
layer, and a number of surface observations around the area still
feature a light southerly wind. Patchy dense fog could still develop
over the next few hours, particularly near Lake Cumberland.

The upper level jet is well off to our north across Canada, and this
will continue to be the case through the short term. Upper level
ridging will build east across the region today through tomorrow,
while the surface high will remain anchored over VA/WV.

This will allow our spectacular stretch of Fall weather to continue,
with afternoon highs warming a few degrees each day. Highs today
will reach the low to mid 70s, with everyone solidly into the mid
70s Friday. Lows tonight will dip back down into the 40s.

.Long Term...(Friday night through Wednesday)
Issued at 320 AM EDT Thu Oct 19 2017

We`ll have another dry, warm day on Saturday as a deep upper trough
moves into the Plains. We`ll likely see quite a bit more high level
cloud cover streaming east from the advancing trough and surface
cold front. Rain chances increase on Sunday, but the most likely
time frame for showers and some storms looks to be Sunday night
through Monday night.

Still some notable timing and synoptic pattern evolution differences
heading into early next week, but the 00z runs of both the GFS and
ECMWF feature a closed upper low developing over the South Sunday
night and splitting from the northern ribbon of shortwave energy.
The surface cyclone then responds by deepening and tracking NNE to
the Great Lakes by Tuesday. In wrapping up the system, the ECMWF
slows it down more and features a more westward track in the new
surface low. Both solutions do, however, suggest a rainy and breezy
period to begin the work week.

As the system continues to strengthen toward the Canadian border on
Tuesday, we`ll see cold air advection ramp up on the backside as a
deep upper trough settles over the Midwest. It continues to look
quite chilly by the middle of next week, with highs only in the 50s
on Wednesday.


.Aviation...(12Z TAF Issuance)
Issued at 645 AM EDT Thu Oct 19 2017

High pressure to our south and east will remain in control through
the valid TAF period. Visibilities up and down overnight at BWG, so
will be a last-minute decision. Worst-case might include a brief
TEMPO for IFR vis, but should be solid VFR by 13Z. Rest of the day
will see unrestricted cig/vis across the board with SW winds just
shy of 10 kt. However, low-level moisture will increase just enough
to support a better chance for fog on Friday morning. Model guidance
is in line with this signal so we will include at least TEMPO groups
for IFR vis early Friday morning except at HNB, where surface winds
stay up just a bit.




Short Term...EBW
Long Term...EBW
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