Area Forecast Discussion
Issued by NWS Northern Indiana

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

FXUS63 KIWX 150528

Area Forecast Discussion
National Weather Service Northern Indiana
128 AM EDT Sat Aug 15 2020

Issued at 356 AM EDT Fri Aug 14 2020

Scattered showers and thunderstorms are possible at times through
Sunday. The best chances most periods will be over northwest Ohio
into northeast Indiana and into far southern Lower Michigan.
Highs will be around 80 to near 85 each day through this weekend
with lows from 60 to 65. Somewhat cooler, less humid and dry
conditions will follow Monday and Tuesday.


.SHORT TERM...(This Evening through Sunday)
Issued at 325 PM EDT Fri Aug 14 2020

Vorticity from an upper low helps to force showers and thunderstorms
this afternoon and evening. Pockets of 1000 to 2000 J/kg of SBCAPE
traverses the area, but with minimal shear to work with. DCAPE
actually does reach around 1000 J/kg across the area and areas west
of I-69 show low level inverted-v profiles allowing for a good
chance for gusty downdrafts. Columnar moisture is limited, however,
paired with slow storm motions and 1.25 in PWATs, could see some
locally heavy rainfall. Expect showers and storms to die down by
sunset tonight and depending on where the rain falls, could see some
fog formation as good subsidence occurs and a fairly strong low
level inversion forms. Lows tonight fall back towards the low to mid

Saturday, the vorticity from the upper low moves east during the day
and the cold front approaches from the west for the overnight. With
1500 to 2500 J/kg of SBCAPE, could see another resurgence of pop up
showers and storms, but this time the question will be what do we
have to force the storms. There is some lingering weak 700 mb vort
energy to work with so perhaps that forces a few showers and storms.
However, there is a better chance that storm formation waits until
the evening for the front to arrive. Some lingering speed shear is
being modeled by the NAM, but otherwise some shear would be
possible associated with the approaching front from the west.
Again, the main threats look to be damaging winds gusts and
locally heavy rain. SPC has tagged the area with a marginally for
the storms forced by the approaching cold front in our west. Highs
Saturday warm to the low to mid 80s.

Sunday, the cold front continues to march across the forecast area
from west to east so that areas mainly east of I-69 have the best
chance for showers and storms. The NAM actually holds the front back
so that it`s over IN-15 by 00z Monday, but the lower res models have
it pushed through by then. Will include some mention of showers and
storms in the aforementioned area, but as previously discussed this
depends on the speed of the front through the area. SPC has a
marginal risk of severe weather in NW OH for this time period. Have
highs cooler again, in the low 80s.


.LONG TERM...(Monday through Friday)
Issued at 325 PM EDT Fri Aug 14 2020

A high amplitude pattern takes over after Sunday`s cold front moves
through with an upper low sliding south from Central Canada and a
building ridge in the west. This allows for northwest flow across
the area and for mid-September like weather. Cooler highs in the 70s
to rising to the low 80s by the end of the week and lows in the 50s
with dry weather will be the main story for this time period. Models
do produce some precipitation for Monday afternoon as a trof moves
through, but am not ready to introduce more than a silent 14 PoP
quite yet with how much dry air is around.


.AVIATION...(For the 06Z TAFS through 06Z Saturday Night)
Issued at 124 AM EDT Sat Aug 15 2020

VFR expected this period, except there is a small chance for MVFR
fog this morning. Scattered showers and thunderstorms can be
expected again this afternoon and evening, with the better chances
near KFWA in the late afternoon. Showers could approach KSBN after
16/00Z with the incoming cold front. Winds will be light and
easterly through today, and will shift to the northwest behind the
front Saturday night.




LONG TERM...Roller

Visit us at

Follow us on Facebook...Twitter...and YouTube at: is the U.S. government's official web portal to all federal, state and local government web resources and services.