Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Jackson Kentucky
930 am EST sun Dec 8 2013
issued at 930 am EST sun Dec 8 2013
Surface temperatures are slowly beginning to climb. Its been apparent
that the greatest threat south of I-64 this morning has been the
ice...while snow/sleet remains a bigger threat to the north. The
freezing rain threat will continue to inch northward this morning
taking over the snow as the warm nose continues to push overhead. It
may take a good chunk of the day for surface temperatures to respond to
the north. Will go ahead and let the southern most portion of the
Winter Weather Advisory expire at the top of the hour as temperatures
have warmed to 33/34 in most areas.
Update issued at 647 am EST sun Dec 8 2013
A band of sleet and freezing rain and snow moving northward across
the forecast area this morning. This band of wintry precipitation
extends from north of the mountain Parkway to the I-64 corridor. Ice
accumulations of around one tenth of an inch still expected with
light accumulations of sleet and snow also possible in the far
northwest portion of the forecast area. The wintry mix will continue
to change over to rain from south to north through this afternoon.
Heavy rain will be possible at times from late this morning through
late tonight...leading to rises on area rivers...creeks...and
streams...and perhaps more flooding problems. The forecast overall
was in good shape with updated Winter Weather Advisory and Flood
Watch products also out. No update to the forecast was needed.
Short term...(today through monday)
issued at 352 am EST sun Dec 8 2013
Complicated forecast for the first half of the day today. Wide band
of wintry precipitation...consisting mostly of sleet...moving across
the central portion of the forecast area at afd issuance. So far only
very light accumulations of ice have been reported with this band of
precipitation. The precipitation so far has been light. With mostly sleet
falling...feel like the ongoing advisory will suffice to deal with
any wintry precipitation that falls over the next several hours. The
far northwestern portion of the area...basically along and north of
the I-64 corridor...could still see a slushy inch or so of snow
today...with around a tenth of an inch of ice accumulation still
expected area wide. The highest ice accumulations would likely occur
across the two tiers of counties across the center of the forecast
area. Did not make many big changes to the first 8 hours or so of
the forecast as the current forecast looks pretty good compared to
ongoing conditions. Made a few modifications here and there per
latest conditions and expected trends. The nam12 and sref model data
was used to shore up the rest of the forecast through 0z
Tuesday...with HPC quantitative precipitation forecast highlights used to calculate the latest
expected rainfall totals today through Monday. Still expecting the
potential for locally heavy rainfall and perhaps further flooding
issues on area rivers...creeks...and streams through the first of the
Temperatures will slowly rise above freezing area wide from south to
north throughout the morning. Highs in the 40s are anticipated this
afternoon southeast of a line from Montana Vernon to Paintsville. Areas
northwest of this line will likely not make it out of the 30s.
Temperatures should remain warm enough Sunday night for all rain to
occur...with highs on Monday rising into the 40s for most of the area.
Long term...(monday night through saturday)
issued at 352 am EST sun Dec 8 2013
Models are in good agreement aloft as they sweep a large...full
latitude trough from the plains into the Great Lakes and gradually
south through the rest of the eastern U.S. By late Thursday or early
Friday. Successive...smaller disturbances or short waves track
through the mean flow of the larger trough with the most significant
providing a chance for some precipitation on Tuesday. Thereafter...
during the latter part of the work week and into the weekend the
pattern will become more split as the eastern trough moves off to
the northeast and a southern stream low crosses the Southern Plains.
This southern stream low appears to phase with energy dropping out
of the intercontinental west before reaching the Tennessee Valley at the
end of the forecast window.
For sensible weather...a surface wave of low pressure or two lifting
northeast along the Arctic frontal boundary draped across the Tennessee
Valley continue a threat of light snow or rain Monday night and into
Tuesday...mainly in our far southeast. High pressure will then build
into the region keeping most of any weather well to the north of
Kentucky through midweek even as cold air filters in to reinforce
the air mass in place over the County Warning Area. A frontal boundary will pass
through the Ohio Valley late Wednesday but should have little impact
on our weather other than to shift our winds and reinforce the cold
air in place across the commonwealth. Dry weather then continues
until the weekend when another system approaches from the west to
deliver our next most likely chance at widespread precipitation.
Temperatures remain below normal through the extended...but with some
moderation towards next weekend due to the approaching storm system.
Aviation...(for the 12z tafs through 12z Monday morning)
issued at 627 am EST sun Dec 8 2013
IFR ceilings with freezing rain and sleet across the area this morning.
Both jkl and loz reporting freezing rain with some pl at tat issuance. The
band of wintry precipitation had just moved north of sme when the taf
was issued. Expecting wintry precipitation to change over to moderate
to heavy rain around 13z at loz and sme...and around 15z at jkl and sjs.
A light glaze of ice will persist through middle morning on all exposed
surfaces...before finally being melted off by the rain. The
widespread rainfall will be the weather issue of note at the taf
sites through Monday morning...reducing visibilities at times to MVFR
levels. IFR to LIFR ceilings will persist at all four taf sites through the
end of the period...with ceilings hovering between 300 and 800 feet.
Winter Weather Advisory until 4 PM EST this afternoon for kyz044-
Flood Watch through Monday morning for kyz058>060-068-069-079-
Winter Weather Advisory until 1 PM EST this afternoon for kyz058-