954 
FXUS61 KILN 210147
AFDILN

AREA FORECAST DISCUSSION
National Weather Service Wilmington OH
947 PM EDT Tue Aug 20 2024

.SYNOPSIS...
The dry and cool airmass remains in place across the region
through mid week. Temperatures warm closer to the weekend and
into next week.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
High pressure remains centered over Lake Superior this evening,
with the Ohio Valley on the southern periphery of the high.
Gusty winds earlier in the day have diminished, with light NNE 
flow settling into the region. Compared to this time last night,
temperatures are running about 5-8 degrees cooler, and dewpoints
are running about 3-6 degrees drier. With mostly clear skies,
outside of some cirrus in the southeastern half of the CWA, this
will be a favorable night for radiational cooling. The min temp
forecast has been adjusted slightly downward in outlying areas,
particularly in central Ohio. Given the very dry air mass, and 
a lack of river valley fog yesterday morning outside of some 
spots in the far southeastern ILN CWA, thinking that confidence 
is low enough to leave this out of the forecast as of now.

Previous discussion >
The blocking pattern with a highly amplified ridge stretching 
from the Hudson Bay down through the Four Corners region remains
in place at the start of the period. This translates to 
continued dry conditions over the region. Daytime cumulus should
dissipate as we head into the evening hours. Radiative cooling 
processes take over and we should see some of the coolest 
overnight temperatures we've had in a while. Just for 
informational purposes, the Big Three records are as follows... 
CVG 45F (1950) CMH 44F (1950) DAY 46F (1950) Have most areas 
dropping into the low 50s/ upper 40s. The only site that may 
tickle a record would be DAY (forecast low of 47F), however, 
would not be surprised to see some low 40s during early morning 
hours in our cooler valley spots. 

Despite the dry air in place (PWATs still ~1.5-2 sigmas below
normal), HiRes guidance suggests that patchy river valley fog
may not be out of the question, though, confidence is low.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM THURSDAY/...
Blocking pattern continues to slowly shift east and Wednesday
will be very much like Tuesday, though with the exception that
it may be slightly less breezy and perhaps we'll see a few less
cu as the center of the surface high continues to creep closer.
Additionally, temperatures on Wednesday should also be a tad 
warmer, reaching the mid 70s. Dry conditions remain in place 
during the overnight hours and any diurnal cu clear out. 
Overnight lows again drop to the low 50s with upper 40s in 
spots. Once again, river valley fog may form but have not
included in the grids just yet.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
Surface high pressure will extend across the region on Thursday. 
After another cool start for mid/late August, plenty of sunshine and 
airmass modification will allow temperatures to warm into the mid 
70s to lower 80s. The center of the surface high will begin to 
settle over the mid Atlantic Thursday night. With light winds and 
clear skies, expect another cool night with lows in the lower to mid 
50s.

Models are generally similar in their upcoming synoptic pattern 
depiction that takes us into the weekend and into early next week. A 
mid level ridge (anomalous high in strength for the time of year) 
will slowly build north and east into the Great Lakes and Ohio 
Valley through this period. Meanwhile, the surface high will be off 
to our east along the eastern seaboard. This pattern will result in 
increasing temperatures each day along with some increase in 
dewpoints/humidity. Will still keep a dry forecast for now, but 
there are some hints that either a weak disturbance or just 
increasing heat/humidity could bring a low chance of a shower/storm 
in the latter part of the weekend into early next week. Otherwise, 
highs in the lower to mid 80s on Friday will warm into the lower to 
perhaps mid 90s by Monday/Tuesday. These temperatures by 
Monday/Tuesday will be some 10 degrees above normal for late August. 
Lows in the 50s to lower 60s Friday night will warm into the mid and 
upper 60s by Monday and Tuesday morning.

&&

.AVIATION /01Z WEDNESDAY THROUGH SUNDAY/...
VFR conditions are expected through the TAF period. Gusty
northeast winds should diminish after 00Z, with light northeast
flow of generally 5 knots or less overnight. The very dry air
mass will preclude fog formation for most locations, though some
MVFR conditions are possible at KLUK, and this has been included
in a TEMPO group.

Tomorrow, conditions will be similar to today, with scattered
diurnal cumulus clouds and NNE winds of about 10-15 knots.

OUTLOOK...No significant weather is expected.

&&

.ILN WATCHES/WARNINGS/ADVISORIES...
OH...None.
KY...None.
IN...None.

&&

$$
SYNOPSIS...CA
NEAR TERM...CA/Hatzos
SHORT TERM...CA
LONG TERM...Hickman
AVIATION...Hatzos