Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 181642

Area Forecast Discussion
National Weather Service Northern Indiana
1242 PM EDT Mon Sep 18 2017

Issued at 1242 PM EDT Mon Sep 18 2017

A weak cold front may touch off a few showers and perhaps a
thunderstorm south of Route 24 this afternoon into early this
evening. Dry and mild conditions are expected elsewhere with highs
in the upper 70s. An upper level system will bring increasing
chances for rain to the entire area later tonight into Tuesday
morning. Lows tonight will drop into the 60s, with highs in the
mid 70s to low 80s on Tuesday. Unseasonably warm and dry
conditions are then expected for the remainder of the week into
next weekend as an upper level ridge builds in.


.SHORT TERM...(Today and Tonight)
Issued at 329 AM EDT Mon Sep 18 2017

Progress of the weak cold front has slowed over the past several
hours as it outruns what limited flow existed to the west of the
area. Pockets of widely scattered, mainly light showers were
persisting across the southeastern half of the area. Hi res models
all point towards this trend continuing through the morning
generally southeast of a Monticello to Wauseon line. Coverage of
showers may increase this afternoon in all areas, especially SE of
this line as steepening lapse rates and increasing instability
occur. However, models have backed off on more extensive coverage
until after 00Z tues and especially after 6Z associated with
another piece of energy moving into the region. As a result have
made changes to pops to better reflect trends today and slower SW
to NE arrival of shower chances later tonight.

Temperatures will be cooler than yesterday given expected cloud
cover and slightly cooler 850 mb temps behind the front. If more
clearing takes place than currently forecasted, highs could nudge
a few degrees higher.


.LONG TERM...(Tuesday through Sunday)
Issued at 329 AM EDT Mon Sep 18 2017

Showers and a few thunderstorms may be ongoing for the start of
the period until the departure of the upper level energy. Slight
chance to chance pops warranted into Tuesday evening before
frontal boundary moves back north of the area.

Models continue to advertise strengthening upper level trough to
the west and strong ridging to the east which should keep the
region high and dry with temperatures 5 to 10 degrees above
normal. While some instability will exist each afternoon/evening
lack of clear forcing mechanisms and influence of high pressure
over the eastern US should curtail any meaningful precip chances
through the remainder of the period. As has been the case the past
several days, have removed spurious pops Tues night through
Thursday night.


.AVIATION...(For the 18Z TAFS through 18Z Tuesday Afternoon)
Issued at 1242 PM EDT Mon Sep 18 2017

A BKN/high MVFR stratocumulus deck at KFWA should lift/mix out to
VFR by 19/20z as drier air mixes in post-frontal. Dry/VFR
conditions and light nne winds can be expected otherwise into this
evening before the front lifts back north as a warm front with
deteriorating flight conditions and increasing rain chances.




LONG TERM...Fisher

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