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Area Forecast Discussion (AFD)

Issued by Wilmington, OH (ILN)

                            
000
FXUS61 KILN 241427
AFDILN

AREA FORECAST DISCUSSION
National Weather Service Wilmington OH
1027 AM EDT Mon Jun 24 2019

.SYNOPSIS...
Thunderstorms will move through today in advance of a cold front.
High pressure and dry conditions will work into the region for
Tuesday. A weak frontal boundary will move through the area for
Wednesday.

&&

.NEAR TERM /UNTIL 8 PM THIS EVENING/...
Update to forecast this morning in a few areas 1) speed up the 
exit of the precipitation chances this evening with a gap 
between pre- frontal rain chances and narrow band of dying 
showers along the cold front that will likely be separated by 
several hours of drying and 2) drop high temps this afternoon 
in the far west with clouds/rain likely to temper any warming. 
Timing and magnitude of rain chances look great so no other
changes. 

GOES East satellite loops and radar mosaics show a large shield
of clouds/rain lifting NNE toward the western side of the ILN 
forecast area at 14Z. Some breaks in the clouds downstream over 
the eastern half of the ILN CWA which is allowing for 
destabilization to begin. Leading area energy over western KY/IN
ahead of strong shortwave trough over IA/MO is driving this 
shield of precipitation northeast into the area. 

RAP/HRRR/CAMs all suggest an evolution to a similar scenario.
Expect the leading shortwave energy over KY/IN to induce weak
surface low / low level circulation across Kentucky /already in
progress/ which will lift rapidly northeast into the Scioto
Valley this afternoon. Attendant to this feature will be noted
increase in low/mid level flow /increased shear profile/ while
this area will also be far enough removed from stratiform
precipitation shield further west to allow for decent
destabilization /MLCAPE to 1000 j/kg. Thus, expect deep
convection to slowly develop over Kentucky /already in progress
near Fort Campbell Kentucky/ and lift into the Scioto Valley 
this afternoon with a favorable overlap of forcing/instability 
and wind shear. Greatest relative severe threat in the ILN CWA 
will be Maysville/Portsmouth/Lancaster corridor between 2 PM and
6 PM before things quickly shunt to the east and stabilize. In 
this corridor, low level flow may back just enough ahead of weak
low level circulation to allow a brief/weak tornado threat with
any discrete cell - but overall storm mode should be 
linear/multicellular/clusters with evolving/expanding cold pools
for primarily a wind damage threat. 

Further west - really liked the 13Z SWODY1 update from SPC which
removed threat from areas west of I-75. Instability minimum is
here during peaking heating owing to thick clouds and
precipitation which will greatly limit severe threat through the
afternoon. Think severe threat slowly increases east of I-75 and
primarily exists east of I-71 to a maximum in the corridor
mentioned above.  

Severe threat aside - all areas get a good dose of rain today
but progressive nature to the forcing and anticipated storm mode
suggest that flash flood threat should remain limited. Most
concern is for local training of the deeper convection in the
Scioto Valley/northeast Kentucky.

Rapid end to the precipitation in the eastern CWA by 6 or 7PM -
with a 3-4 hour gap between that back edge - and cold frontal
forced showers approaching the CWA after 10 PM. These will be in
a weakening/dying state late in the evening to early overnight
and only warranted a 15-25% coverage before dissipation.  

&&

.SHORT TERM /8 PM THIS EVENING THROUGH 6 PM TUESDAY/...
Thunderstorms will be ongoing at the start of the short term,
however expect them to move out of the region early in the short
term. Some residual shower activity will remain through around
midnight before pushing out of the region.

High pressure and dry conditions will work into the region for
Tuesday. Went close to guidance for temperatures with high
temperatures in the lower 80s. Winds will gust at times again
with wind gusts ranging from 20 to 30 mph.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
Heights will be rising at the beginning of the period, but a short 
wave moving across the Great Lakes will help push a boundary into at 
least northern Ohio and Indiana on Wednesday. Outside of the 00Z 
GFS, the trend has been for associated convection to be further 
north. Still have low chance PoPs across the entire area, but if 
trends continue, then it is possible that much of the forecast area 
could be dry on Wednesday.

Upper ridge will build into the area for the end of the week. Cannot 
rule out isolated diurnal convection Thursday and Friday, but at 
this point forcing looks limited and weak. A deep trough over 
eastern Canada will push southeast over the weekend. The tail end of 
this trough will brush by the region but also push a back door cold 
front across the area. This will bring a chance of showers and 
thunderstorms both Saturday and Sunday. 

Temperatures will be above normal through the period with Friday 
being the warmest day of the week.

&&

.AVIATION /14Z MONDAY THROUGH FRIDAY/...
Generally dry conditions are expected at the start of the TAF
period. Some MVFR and IFR cigs will near KDAY this morning and
therefore have a tempo MVFR cig in for a couple hours.  Winds 
will begin to pick up during the day today with wind gusts 
around 20 to 25 knots possible outside of thunderstorm activity.
An approaching cold front will allow for shower and 
thunderstorm development during the day. Timed in the best 
chance for thunderstorm activity today. Vsbys will be reduced 
with the thunderstorm activity.

Residual shower activity will linger into the night, however
expect dry conditions to return by the end of the TAF period.

OUTLOOK...Thunderstorms are possible Wednesday.

&&

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

&&

$$
SYNOPSIS...Novak
NEAR TERM...Binau
SHORT TERM...Novak
LONG TERM...
AVIATION...Novak