Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 190005

Area Forecast Discussion
National Weather Service Northern Indiana
805 PM EDT Thu May 18 2017

Issued at 410 PM EDT Thu May 18 2017

Some scattered showers and isolated storms are expected this
evening, primarily along and south of Route 24. Noticeably cooler
air will then filter in overnight behind a cold front. Highs on
Friday will run about 15 to 20 degrees colder than today. Rain
chances return for the weekend as the frontal band lifts back
northward, with the best chances Saturday afternoon into Saturday


.SHORT TERM...(This Evening through Friday)
Issued at 356 PM EDT Thu May 18 2017

Corridor of 1000-1500 j/kg along with effective deep layer shear
of 30 knots with convection starting to fire amid prior robust
roll/cu streets. Lack of significant severe parameters, low level
forcing stabilizing boundary layer beyond 00 UTC and overall mid
level height rises. Upstream cold front attendant to dampening
yoop mid level vortex to bring substantially cooler albeit shallow
boundary layer south of cwa by daybreak Friday. Ensuing shower
chances on flank of return/elevated warm air advection
wing/especially southwest third to half cwa but not expected to be
widespread/robust until much later in weekend.


.LONG TERM...(Friday Night through Thursday)
Issued at 356 PM EDT Thu May 18 2017

As greater mid/upper level support lifts out of central Rockies
and into Upper Midwest/Mississippi Valley expect more fervor to
moisture return/destabilization for greater coverage of shra/tsra
Sat afternoon into Sat night. Drier/cooler behind second cold
frontal passage to start early next week followed by a strong
northern stream wave to redig cyclone farther south over southern
portions of Upper Great Lakes into Lower Ohio Valley. A bit more
selective with thunder chances, relegated to lesser slight chances
Tuesday afternoon with lesser low level lapse rates thereafter in
deeply cool/stacked system.


.AVIATION...(For the 00Z TAFS through 00Z Friday Evening)
Issued at 805 PM EDT Thu May 18 2017

Last in a series of storms will work across the KFWA airfield
thorugh 0030Z. Otherwise upstream stratiform shra
Upstream showers may extend through 01Z yet line continues to sag
swd and with diurnal instability waning...will continue to weaken
with time.

Elsewhere lake breeze had composited in with sfc cold front dropping
through nrn IN with rapid veering in its wake. Front xpcd to stall
through srn IN overnight and then begin mixing back north on Fri
ahead of potent upstream disturbance over the srn plains. As such
VFR conditions will hold through the period although shallow over
running Fri am likely to yield a lower bound VFR bkn stratocu deck.
Winds will continue to veer to easterly on Fri and stay aob 10 kts.


LM...Small Craft Advisory until 11 AM EDT Friday for LMZ043-046.



LONG TERM...Murphy

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