Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Jackson Kentucky
345 am EDT sun Mar 9 2014
Short term...(today through monday)
issued at 345 am EDT sun Mar 9 2014
The latest surface map features a weak cold front aligned from the
middle-Atlantic down across the Tennessee Valley...with high pressure
centered across the Southern Plains. The cold front brought some
light rain showers across eastern Kentucky earlier...with just some
patchy drizzle currently leftover in its wake.
High pressure will work in from the west today...with low clouds
gradually diminishing through the morning from north to south. Highs
will be cooler today...ranging from near 50 north of I-64...to the middle
50s bordering Tennessee and Virginia. High pressure will weaken and
become more consolidated across the Gulf through Monday...allowing
for return southwest flow. This will set the stage for a decent
Ridge/Valley temperature split tonight...with cooler locations
likely dipping down below 30 degrees...while broader valleys and
ridges stay in between 35 and 40 degrees under mostly clear skies.
Monday will feature a mostly sunny day...besides a few passing higher
clouds and perhaps a touch of cumulus. Southwest winds...gusty at times...
will help to push highs back into the lower and middle 60s.
Long term...(monday night through saturday)
issued at 345 am EDT sun Mar 9 2014
Continuing to track a split flow set up heading into the
extended...with general flow being westerly...and low level winds
bringing in warmer southerly air. This pattern will continue our
more Spring-like trend through the middle week...at which point a
closed low affects the region...followed by a deepening trough that
will bring the return of colder air by late day 4. Luckily this
trough will be progressive...and quickly move out of the
region...bringing the return of more zonal flow and warming temperatures
through the remainder of the extended.
Main concern during the extended period will be the above mentioned
closed low and troughing that will move eastward and affect much of
Kentucky Tuesday night through Wednesday night. At the surface...a low
pressure system will continue to gain strength during the day
Tuesday across the Southern Plains...before making the push eastward
fairly quickly into Kentucky by Wednesday evening/night. This will push a
cold front across the region...and be The Gateway for the colder
push of Arctic air flowing into the region Wednesday afternoon and
continuing through Thursday.
Models seem to be coming into a better agreement with this latest
run as far the precipitation that will accompany this system.
Several things will be interacting that will influence the extent
and type of precipitation we will receive. First...the closed
shortwave to the south...along with southerly winds ahead of the
front...will both work to pull in warm and moist Gulf Coast air.
With Kentucky/S location in the split flow pattern...warm air being
brought in...but colder Arctic air to the north...another baroclinic
zone will set up...also helping to intensify precipitation over the
region. With the initial push of warm air...and pre-existing warm
conditions...expect the majority of the precipitation to fall in the form
of rain beginning Tuesday night and into Wednesday. Then as the
system passes over Kentucky...it will continue to gain strength...allowing
moisture to become wrapped around the backside and continue to
affect Kentucky even after the frontal passage. Temperatures will begin
falling Wednesday afternoon behind the front...reaching the freezing
mark by late Wednesday evening. Models are still in a bit of
disagreement about the timing and extent of this wrap around
moisture...but still in good confidence that it will linger during
and after temperatures have fallen below freezing. Quantitative precipitation forecast remains quite
low...but could be enough to see rain change over to snow...with a
light dusting of accumulation across portions of the area. The European model (ecmwf)
tries to pull the moisture out the quickest...by 12z Thursday...but
both the Gem and GFS are showing some lingering moisture across the
highest terrain through the morning hours. Previous experience with
lingering moisture and upslope flow would tend to lean more towards
the Gem and GFS solutions at this time.
Overnight lows both Wednesday night and Thursday night will drop
back down into the 20s...but a warm front to our north and winds
turning more southerly by Friday will work to boost temperatures back up
into the 50s for days 6 and 7...with overnight lows in the upper 30s
to around 40.
Aviation...(for the 06z tafs through 06z Sunday night)
issued at 140 am EST sun Mar 9 2014
MVFR to IFR ceilings and or visibilities will move in from northwest
to southeast behind a cold front. Some patchy drizzle may also occur.
Winds will shift to the northwest behind the front at around 10 kts.
Lower ceilings will mix out by mid-morning...with a return to VFR
conditions thereafter. Winds will become more westerly during the
day...and will range from 5 to 10 kts.