Area Forecast Discussion
Issued by NWS Paducah, KY
FXUS63 KPAH 260834
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PADUCAH KY
334 AM CDT Sat Jul 26 2014
.SHORT TERM...(Today through Sunday night)
Issued at 249 AM CDT SAT JUL 26 2014
Biggest forecast challenge this period is on how to deal with
MCS development this afternoon and possibly again early tonight.
Much of the meso-convective models this morning point to rapid
destabilization this afternoon as surface temperatures soar into
the 90s and dew points climb into the upper 60s to near 70. Thing
is, most of the region should remain under thermal capping until
later in the day. MCS development is likely to occur over se IA and
west central MO this afternoon, then propagate ese toward the I-70
and I-64 corridors late in the day as the capping weakens. There is
some question as to whether this initial convection will brush by
just to our north or actually clip the I-64 corridor of IL/sw IN.
Given the extreme instability expected and decent wind fields
aloft, what convection does form later today has a very good
chance of being severe at times, with damaging wind gusts, large
hail and even isolated tornadoes possible. Even if this initial
convection/MCS misses our forecast area, additional thunderstorm
development will be possible along its outflow boundary early this
evening and into the night.
Cold front enters the scene late tonight into Sun AM, and will
likely be located somewhere near the OH River by noon. Depending on
the degree of heating that can occur along ahead of this front,
more strong thunderstorm development could occur in areas along
and south of the OH River Sunday afternoon. Should finally clear
out Sunday night behind the sfc front as much cooler and drier air
flows back into the region.
.LONG TERM...(Monday through Friday)
Issued at 249 AM CDT SAT JUL 26 2014
A very tranquil week is coming up for the region next week. By 12Z
Monday, the upper level wave and associated sfc front will be in the
eastern Great Lakes region and will continue to move off the eastern
seaboard by 12Z Tuesday. During the week, our region will be under
the influence of a large trough across the eastern half of the
country, with amplified ridging taking place out west. Models bring
a weak lobe of energy southward across the area on Monday, but it
should only result in some passing clouds, as moisture is limited.
The 00Z NAM/GFS hints at a possible shower to two in parts of
southwest IN where moisture might be a little better, but will leave
dry for now. However, the bigger story to start out the week, will
be the below normal temperatures.
High pressure from central Canada will migrate south/southeastward
toward us early next week and bring a much cooler/drier airmass into our
region. While we will see much cooler temperatures on Monday as
compared to the projected weekend heat, the coolest air will likely
take until about Tuesday to arrive. This means that we should
experience another few degree drop in temperatures then, with some
places likely only reaching the upper 70s for highs. Guidance
numbers have been rather consistent for the past few days so no real
changes to temperatures needed right now.
With high pressure influencing the weather through at least
Thursday, we should expect a mainly rain free forecast with
temperatures moderating back into the low to mid 80s by mid to late
week. Northwest flow can be tricky with regards to figuring out if
there could be any decent chances for rain, but moisture will
definitely be limited to just the lower levels. By Thursday night
and into Friday though, the sfc high breaks down and deeper moisture
advects into the area. This increase in moisture, along with a lobe
of energy pivoting down in the northwest flow aloft, could mean some
chances convection by the end of the week.
Issued at 620 PM CDT FRI JUL 25 2014
A warm front is forecast to move eastward across the TAF sites
through the period. With the exception of MVFR fog at KCGI/KPAH,
VFR conditions should prevail at all sites through the period.
Southerly winds AOB 6 knots will continue through the night, then
pick up out of the south southwest after 15Z generally AOB 10
knots, however there could be gusts up to 15 knots at KCGI/KPAH.