FXUS63 KJKL 192320
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
720 PM EDT Thu Jul 19 2018
Issued at 720 PM EDT THU JUL 19 2018
A few small showers/thunderstorms have popped up in southeast KY.
Will look for them to die out with loss of heating this evening,
but in the mean time, have added a 20 percent POP.
.SHORT TERM...(This evening through Friday night)
Issued at 303 PM EDT THU JUL 19 2018
A very challenging forecast in store for the latter half of the
short term. The primary forecast issues will be the potential for
severe weather late in the day on Friday and heavy rain and
flooding Friday night. At this time, the various forecast models
are in very poor agreement regarding the timing of the passage of
a cold front and upper level trough tomorrow night and Saturday
across the region. The front would normally prove to be the
primary catalyst for storm initiation, but the timing of the front
is in question. There is also the potential, depending on which
model you believe, for outflow boundaries left over from early
morning convection to act as triggers for new storm formation
Friday afternoon. There will also be the potential for locally
heavy rainfall that could lead to flooding issues Friday night.
All that being said, and accounting for the amount of uncertainty
involved, have decided to focus on the Friday afternoon and
evening time frame for the potential for severe weather, with a
gradual transition to heavy rain and flooding potential Friday
night. The primary severe weather threats for Friday afternoon and
evening will be damaging winds and large hail.
Temperatures will continue to be warm, with lows the next two
nights forecast to fall into the mid to upper 60s across the area.
Highs on Friday should be tempered somewhat by cloud cover and
precipitation. Highs are expected to be mostly in the low to mid
80s across the area, which is slightly below normal for this time
.LONG TERM...(Saturday through Thursday)
Issued at 359 PM EDT THU JUL 19 2018
The models are in good agreement with an amplified long wave
pattern to remain in place across the country, as ridging
dominates across the southwestern CONUS, while troughing rules
east of the Mississippi River. An upper level low will gradually move
south from the Great Lakes to the Gulf Coast by late Tuesday,
keeping unsettled weather across the Ohio and Tennessee valleys.
Another trough will be moving east within the northern stream
across south central Canada, bringing another surface cold
front through our region into Wednesday. At least modest
troughiness will linger into Thursday, allowing for a continued
threat of chance POPs.
This weekend, likely to categorical POPs will be on tap as the
upper level and surface lows draw closest to the region.
Depending on how much rainfall occurs leading up to this system,
some localized flooding may be possible this weekend. POPs then
become more diurnally influenced into early next week, before the
next front approaches Wednesday. Temperatures will start out below
normal for the weekend and then trend more towards normal next
.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
ISSUED AT 145 PM EDT THU JUL 19 2018
Surface high pressure has shifted to the northeast of the
Commonwealth, bringing one more day of dry conditions today. This
will keep all TAF sites at VFR until a low pressure system brings
showers and thunderstorms into the Ohio Valley beginning tomorrow
morning. With this system, MVFR conditions as well as VCTS will
overspread all TAF sites by 12Z and last through the end of the
TAF period. However, there still remains a fair amount of
uncertainty with the timing of the system moving into eastern
Kentucky. Southeast winds at around 5 kts will become more
southerly and increase to 5 to 10 kts by tomorrow afternoon.
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