Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

000 
FXUS63 KJKL 201146 AAA
AFDJKL

AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
746 AM EDT Sun Aug 20 2017

.UPDATE...
Issued at 746 AM EDT SUN AUG 20 2017

Freshened up the hourly temperatures and dew points through
this morning, otherwise the forecast remains on track. 

&&

.SHORT TERM...(Today through Monday)
Issued at 313 AM EDT SUN AUG 20 2017

The latest surface map features a weak quasi-stationary frontal
boundary located just north of the Ohio River, amidst high 
pressure generally sprawled from the eastern Ohio Valley down 
through the southern Appalachians. Aloft, a short wave trough is 
pulling away across New England, with rising heights across the 
lower and mid-Mississippi Valley. 

Warming temperatures and mostly clear skies will be on tap across
eastern Kentucky through the short term, as an upper level 
ridge builds in across the southeastern CONUS. Highs will average
in the upper 80s today, with lows in the mid to upper 60s tonight.
Expect some diurnally driven cumulus, but little in the way of
upper level clouds. For Monday, some thin cirrus will be 
advecting in from the northwest during the day, and there will also
be a touch more afternoon cumulus, given the slight uptick in low
level moisture. Overall, this should not impede a good viewing of
the eclipse. Highs will be in the upper 80s once again, with a few
to several degree drop in temperatures during the peak of the 
eclipse. 

.LONG TERM...(Monday night through Saturday)
Issued at 323 AM EDT SUN AUG 20 2017

Strong upper level ridging in place will begin to break down Monday 
night as a longwave trough pushes into the Ohio Valley. This trough 
will remain in place, deepening, through the remainder of the work 
week. Models are in good agreement of this troughing pattern through 
this time, having it finally exiting east of the state during the 
day Friday. Increasing heights are expected through the weekend, 
though both the GFS and ECMWF are supporting generally WNW flow and 
a couple of shortwaves passing eastward through the state as we head 
into the weekend.

At the surface, still expecting a cold front to be located NE of the 
region, in the Upper Mississippi Valley and Upper Great Lakes 
Tuesday night. Meanwhile, surface high pressure will begin exiting 
the state to the SE, allowing for return flow across the state ahead 
of this approaching frontal boundary. The front is poised to make it 
to the Ohio River during the late evening Tuesday, traversing the 
CWA Tuesday night and into the day Wednesday, getting briefly hung 
up along the high terrain, before exiting to our SE by Wednesday 
afternoon. With the increased SW flow ahead of the system, shower 
and thunderstorm chances are expected to begin plaguing the CWA 
during the day Tuesday, increasing in coverage along the frontal 
boundary Tuesday night into Wednesday morning. Once the front 
passes, much more stable air will move in behind, quickly cutting 
off any remaining thunder potential in the leftover precip. Have 
only rain mentioned for late Wednesday afternoon and into Wednesday 
night, though wouldn't be surprised if dry air moves in quick enough 
to cut off precip chances quicker than forecast.

For the remainder of the work week, surface high pressure will be in 
place. The upper level troughing in place will promote NW flow 
across the region, helping to keep temperatures at bay (below 
seasonal normals). Highs Wednesday will be in the upper 70s, with 
upper 70s to around 80 expected through the end of the forecast 
period. Northerly winds will also promote less humidity, making for 
pleasant conditions into the weekend. Despite the strong high 
pressure in place, the above mentioned shortwaves that may pass over 
the region during the weekend could lead to a stray diurnally driven 
shower or thunderstorm. The best chance for this will be Sunday as 
the high starts to drift to our NE and more southerly flow makes it 
back into the region. 

&&

.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
ISSUED AT 746 AM EDT SUN AUG 20 2017

IFR or worse fog will be burning off through 13z. A few cumulus 
at around 5k feet agl will be seen during the day, before 
dissipating through dusk. Patchy fog will develop once again in 
the valleys after 06z. Winds will average less than 5 kts through 
the period.


&&

.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

National Weather Service Glossary of Abbreviations