Scientific Forecaster Discussion
Area forecast discussion...updated
National Weather Service Jackson Kentucky
650 am EST Friday Mar 7 2014
issued at 645 am EST Friday Mar 7 2014
Light returns continue to show up in the far east...though no
reports or observation of any precipitation making it to the surface have been received.
Have continued low probability of precipitation in the grids for this assigning flurries or
sprinkles to the weather term. Also...issued a graphical Nowcast to address
this. Have updated the grids to mainly tweak the T/TD/sky grids per
current conditions and trends. These have been sent to the ndfd and
Short term...(today through saturday)
issued at 325 am EST Friday Mar 7 2014
07z surface analysis shows low pressure moving up the southeast coast.
This is throwing middle and high level clouds back west into far eastern
Kentucky. The nearest measurable precipitation still appears to be at least a
County or so on the other side of the Virginia border where rain and
snow have been reported. A few specks of likely just virga are
showing up in the latest radar scans over far eastern parts of the
County Warning Area. Temperatures through the area vary mainly by ridge and valley
with the former in the middle and upper 30s while the latter have
dropped into the upper 20s. Should any of those rogue returns reach
the ground in the valleys there could be some freezing on elevated
sfcs...but the risk of actual icy spots developing is quite remote.
The latest hrrr continues to support minimal probability of precipitation across the area
through this morning. However...will continue to closely monitor the
situation for possible inclusion in the forecast if the returns
become more distinct and persistent.
The models are in good agreement aloft through the short term
portion of the forecast as they all take the southeast low to the
northeast and just off shore as it passes Cape Hatteras later this
evening. Upstream from this...east Kentucky be in the midst of flat
ridging at middle levels with some hints of very weak energy riding east
out of the High Plains. A developing trough well to the west will
interact with another trough moving in the northern stream later
Saturday. This northern feature will then cut southeast into the Ohio
Valley and across Kentucky Saturday night with a blend of the similar
GFS and European model (ecmwf) preferred over the slower Gem solution.
Sensible weather will feature a quiet and mild period of weather in
the wake of the exiting southeast low. Weak high pressure will hold
court through the day Friday and into Saturday ahead of an
approaching cold front from the northwest. This front will bring in
lowering and thickening clouds through the day Saturday before
rain chances spread into the County Warning Area from the north later that evening
and overnight. Have brought in some low probability of precipitation for this starting late
in the afternoon over locations generally north of Interstate 64.
Used the consshort and bcconsshort as a starting point for T...TD...
and wind grids through the first part of tonight. For the remainder
of the short term the consall and bcconsall were blended into the
existing forecast before minor adjustments. As for probability of precipitation...have gone a
bit higher than guidance for probability of precipitation late Saturday...otherwise they
were kept near zero.
Long term...(saturday night through thursday)
issued at 445 am EST Friday Mar 7 2014
The models are in good agreement with a split flow pattern regime to
reign across the Continental U.S.. details within the general flow remain more
uncertain...especially by the middle of next week. As such...have
stuck close to the blended guidance.
A cold front will move through the Ohio and Tennessee valleys Saturday
night into early Sunday morning...providing a good chance of light
rain. Dry weather will follow and continue into Tuesday...before a
more significant storm system takes aim at the area from late
Tuesday afternoon through early Thursday morning.
The models remain in disagreement with this system...with a less
phased...faster...and weaker solution advertised by the GFS...while
the European model (ecmwf) remains more phased...slower...and deeper. As such...have
stuck close to the given blended guidance...allowing for good chance
to likely probability of precipitation Tuesday night into early Wednesday...and chance probability of precipitation
continuing into early Thursday. Colder air will wrap in behind the
system...allowing for the chance of some snow before the moisture
For temperatures...readings will moderate to well above normal
through early next week...with highs peaking on Tuesday in the middle
60s. Temperatures will then return to below by Thursday...with highs
back down into the 30s and 40s.
Aviation...(for the 12z tafs through 12z Saturday morning)
issued at 650 am EST Friday Mar 7 2014
VFR conditions will persist through the taf forecast period. An area
of low pressure tracking to the southeast of Kentucky will continue
to support scattered to broken middle and high level clouds across
the eastern portion of the area this morning...but any measurable
precipitation will likely stay east of Kentucky and the taf sites.
The clouds will clear out to the east by early afternoon. Light and
variable winds can be expected through the period.