Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Jackson Kentucky
108 am EST sun Nov 29 2015
issued at 957 PM EST Sat Nov 28 2015
An upper level wave that was located along the cold front earlier
this afternoon has since moved east of the area. This is allowing
the once widespread light to moderate rain to show signs of
deterioration. As such...updated probability of precipitation to better reflect the
current conditions...which includes drying along the southeast
portion of the County Warning Area...and more scattered activity everywhere else
except for the far north. As the actual cold front continues to
shift eastward toward the County Warning Area...expect rain showers to pick back
up again later on tonight...though northerly air behind the front
will work to scatter out showers in the north by daybreak.
Also...given that rain is ongoing throughout the region...went
ahead and changed probability probability of precipitation to coverage probability of precipitation through today.
A new forecast package will be sent out to reflect these changes.
All grids have been been sent to ndfd and the web.
Update issued at 730 PM EST Sat Nov 28 2015
Forecast seems to be well on track as some of the more steady
widespread rain starts to ease its way into eastern Kentucky just ahead
of the cold front. According to the latest observation and the mesonet
precipitation totals...it seems as though much of the far eastern
Kentucky sites have measured and are receiving rain. As such...went
ahead and expanded the definite probability of precipitation eastward to encompass all of
the County Warning Area for the next few hours. Other edits included loading in
the latest observations for temperatures...dew points...and winds into
the near term forecast to make sure that the current conditions
were well reflected. This resulted in only minor adjustments. All
grids were saved and sent to the web and ndfd.
Short term...(this evening through Sunday night)
issued at 227 PM EST Sat Nov 28 2015
Early this afternoon a cold front extends from southeast Ohio to south of
Cincinnati then southwestward south of the Ohio River on into
western Kentucky. There is a weak wave along the front over western Kentucky.
As this wave moves east rain will increase across eastern Kentucky for
the early evening...and once the wave slips east the front should
continue its slow sag to the south...with rain chances temporarily
decreasing for later tonight. There is good model agreement on
the front making its way to the Tennessee and Virginia borders by early Sunday
afternoon before stalling. A second wave should move along the
front Sunday into Sunday night keeping rain chances across the
area with the best chances across the southern part of the
forecast area. Rain and clouds will limit the diurnal temperature
range...but as the front slips south cooler air will slide into
the northern part of the forecast area for Sunday and Sunday night.
Long term...(monday through saturday)
issued at 333 PM EST Sat Nov 28 2015
A frontal boundary is expected to be stalled to our south in east
Tennessee at the start of the period...with the bulk of the rain
temporarily to our south. A large upper level low over The
Rockies Front Range/High Plains region will move east toward the
Great Lakes early in the week. This will bring surface
cyclogenesis over the middle of the nation...with the surface low
also tracking toward the Great Lakes. It will initially pull the
frontal boundary back north...resulting in a return of showers for
the local area. A cold front spiraling around the low is expected
to pass through on Tuesday afternoon or evening. Drying behind the
front should finally bring an end to the wet weather from northwest to
southeast...with fair and seasonably cool weather finishing the week. The
GFS has backed away from its threat of late week precipitation from a southeast
coastal system...and the European model (ecmwf) remains dry...so have removed the
low probability of precipitation which were in the forecast.
Aviation...(for the 06z tafs through 06z Sunday night)
issued at 108 am EST sun Nov 29 2015
Variable conditions continue this morning as a very slow moving
cold front continues to sag southward across eastern Kentucky.
Areas of rain have been intermittent and scattered leading to
ceilings to vary between MVFR and IFR. However...LIFR ceilings are likely
behind the front...and this is already apparent at ksym where the
front just pushed through. Brief gusty winds are also possible
with the frontal passage. The front will eventually reach the Tennessee
and Virginia borders by this afternoon where it is expected to stall.
This front will be the focus for continued rain...and will also
help lower ceilings throughout the day today as it pushes through the
area. Therefore...expect light rain and mainly IFR to at times LIFR
conditions to persist through the taf period. Winds will be light
and variable except with the frontal passage.