Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Jackson Kentucky
1047 PM EDT Monday Jun 1 2015
issued at 1046 PM EDT Monday Jun 1 2015
Precipitation is all south and east of the jkl forecast area. Can not
rule out some showers sneaking back into our southeast counties...but the
pop for tonight was able to be lowered further.
Update issued at 714 PM EDT Monday Jun 1 2015
A few light showers remain...especially in the southeast part of
the area...but most precipitation has exited and is south and east of the
jkl forecast area. Models do not suggest much in the way of
redevelopment tonight...and have trimmed back probability of precipitation.
Short term...(this evening through Tuesday night)
issued at 355 PM EDT Monday Jun 1 2015
18z surface analysis shows an area of low pressure over far southeast
Kentucky along a cold front that has pressed deep into the County Warning Area.
This boundary is being dragged south with the help of a cluster of
storms moving east through eastern Kentucky at this time with heavy rains
and some lightning strikes. Otherwise...mainly showers and patches
of fog are found through the area with very cool middle afternoon
temperatures for our northwest counties while the southeast
managed to get close to normal before the rain moved in.
Specifically...readings ranged from the middle 50s in the Bluegrass
to around 80 degrees near the Virginia border this afternoon while
dew points varied from the middle 60s ahead of the boundary to the
lower 50s well behind it. Winds for much of the area are from the
north at 5 to 10 miles per hour and light and variable nearer the Virginia
border. For the day...the sky has been covered by low clouds with
only some temporary improvements as the storms moved through the
far southeast. The thunder has been limited to the far east for
most of the afternoon and expect this to be the case into the
first part of the evening as the western parts of the area has
The models are in fairly good agreement aloft through the short
term portion of the forecast primarily dealing with the slow
eastward movement and deepening of a closed low over the area. The
core of this system will contain middle level energy around its
center that will swirl over eastern Kentucky for at least the next
48 hours. Have followed a general model blend for this forecast
with an emphasis on the hrrr and nam12 for details .
Sensible weather will feature gradually diminishing storms and
coverage through the evening as the instability wanes. Following
this...the upper low will keep the clouds low and showers around
the area along with areas of fog. The best precipitation chances will be
east of the low center through the period. Along with
this...thunderstorms will possible in the afternoon and early
evening on Tuesday...with a continued threat of showers in the
far east into Tuesday night...along with patchy fog.
Once again started with the shortblend for the T/TD/wind grids
into Tuesday before populating with the superblend through 12z
Wednesday. Made only small ridge and valley temperature
adjustments for lows and hourly temperatures both tonight and Tuesday
night. As for probability of precipitation...ended up generally in line with a blend of
the wetter mav numbers and the drier met through the period.
Long term...(wednesday through monday)
issued at 250 PM EDT Monday Jun 1 2015
Models are coming into better agreement with respect to the upper
level low this week. With this...confidence is improving on the
forecast through much of the week. The model trend towards keeping
the upper level low more centered over eastern Kentucky continues.
This will keep plenty of cloud cover in place through the week. It
will also set up some diurnally driven showers each afternoon from
Wednesday through Friday. However...instability really does not
recover until we get closer to Friday...so will leave thunder out
except for late in the week. Modified soundings (75/60) only
yields 400j/kg of cape on Wednesday and just slightly better
600j/kg using 78/60 on Thursday. By Friday...warmer temperatures
should return...boosting cape values a bit higher. The upper level
low will slowly migrate eastward through the week...but won't
really get pushed out until Saturday when a kicker shortwave drops
across the Ohio River valley...finally booting the upper level low
out of the picture. However...this may provide the area with
better chances for showers and storms as better forcing moves in
overhead. Will continue to go with the highest chances for rain
each afternoon...although by Saturday...probability of precipitation may be tied more to
the shortwave energy and thus may not show as much of a diurnal
trend. Will remain below guidance on highs through Thursday with
the upper level low overhead...and trend back towards guidance for
Friday through the weekend as highs return to the 80s.
Aviation...(for the 00z tafs through 00z Tuesday evening)
issued at 851 PM EDT Monday Jun 1 2015
At the start of the period...conditions were mostly IFR...with
some low end MVFR. The poor conditions were due largely to
ceilings. This general scenario should persist through the night.
On Tuesday...improvement is expected from middle-morning to middle-day
as ceilings rise and start to break up...with a return to
generally VFR in the afternoon.