Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 250816

Area Forecast Discussion
National Weather Service Northern Indiana
416 AM EDT Tue Jul 25 2017

Issued at 409 AM EDT TUE Jul 25 2017

High pressure will provide another comfortable day with relatively
low humidity and high temperatures near 80. A brief warmup will
occur Wednesday prior to the arrival of a cold front. Highs will
reach the middle 80s with slightly higher humidity. Showers and
thunderstorms are likely late Wednesday night into Thursday. Some
storms could be severe along with heavy rainfall, especially over
north central Indiana. Drier and cooler conditions will return
Friday and continue into the weekend.


.SHORT TERM...(Today and Tonight)
Issued at 408 AM EDT Tue Jul 25 2017

Quiet and comfortable weather for late July expected through
Wednesday. High pressure centered over the Great Lakes will
continue to slowly slide east today. Highs expected to top out
near 80 with comfortable dew points in the 50s to lower 60s. As
the high moves to the mid Atlantic region on Wednesday low level
flow will become more southerly allowing a return of low level
moisture. Dew points will creep up slowly during the day but
should remain in the 60s. Coupled with temps into the lower and
middle 80s it will feel a little more humid, especially in the
southwest, but nothing oppressive.


.LONG TERM...(Wednesday through Monday)
Issued at 408 AM EDT Tue Jul 25 2017

Focus in the long term period is Wednesday night and Thursday with
possibility of MCS producing severe weather and heavy rainfall once
again. Outside of this system, remainder of long term looks quiet
and quite comfortable for late July.

Moisture will continue spreading northeast Wednesday night ahead of
a strong short wave and approaching cold front. Models coming closer
together on timing of this system. Seasonably deep and convectively
enhanced low pressure is shown by most models to develop along
surface front late Wednesday and move into western CWA overnight.
Strong deep layer shear on order of 50-60 knots expected as mid
level flow increases. Surface low a concern as low level winds back
significantly yielding strong low level directional shear. Overnight
timing though complicates severe potential as instability is limited
with MUCAPEs between 1000-1500 j/kg. However, this may be enough to
sustain approaching MCS into our southwest counties with a severe
wind risk and even an isolated tornado possibility if winds
indeed back near the warm front.

Heavy rainfall and possible flooding just as much of a concern as
model PWATs are well over 2 inches and warm frontal boundary will be
near southern counties that have seen their share of heavy rainfall
over last month. Low level jet of 30-35 knts coincident with theta-e
surge is focused into this region and being lifted over warm front.
Rainfall amounts of 1 to 2 inches look easily obtainable and locally
higher amounts not out of question if storms train north of surface

Lingering showers and storms expected Thursday with decreasing pcpn
chances from west to east during the day. High pressure then moves
back in to the Great Lakes and remains in place through the weekend.
Fast moving weak short wave may move through the region late in the
weekend or early next week but pcpn chances and amounts look small
at this time.


.AVIATION...(For the 06Z TAFS through 06Z Tuesday Night)
Issued at 1252 AM EDT Tue Jul 25 2017

Sfc High pressure ridge movg east across the wrn grtlks overnight
will result in little cloudiness with light/variable winds. Dwpt
depression down to 0-4F now across nrn IN and some ifr vsbys in
fog have been reported at MGC. Based on eve soundings and bufr
fcst soundings, low levels too dry for anything more than ground
fog mainly in rural locations, so continued with vfr conditions
in the tafs. As sfc ridge moves east Tuesday, light e-se flow will
develop across the area. VFR will continue with just a few cu
psbl during the aftn along with some cirrus debris spilling se
from nrn plains/upr midwest convection.




SHORT TERM...Lashley
LONG TERM...Lashley

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