Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 171046

Area Forecast Discussion
National Weather Service Northern Indiana
646 AM EDT Tue Oct 17 2017

Issued at 332 AM EDT Tue Oct 17 2017

A breezy and sunny day is in store for the region, with high
temperatures in the 60`s. Expect continued dry conditions and a
gradual warming trend through the rest of the work week. Highs will
range from the upper 60`s to low-mid 70`s through the weekend.  The
next chance for rain will be late Saturday night into Sunday as a
frontal boundary works its way through the forecast area.


.SHORT TERM...(Today and Tonight)
Issued at 332 AM EDT Tue Oct 17 2017

Our quiet stretch of weather continues through the short term, as
surface high pressure expanding from the central and southern
plains rests overhead. This high will expand and strengthen
through the week. On the northwest side of the high lies a weak
shortwave/trough (per obs/satellite) that will serve to gradually
tighten the pressure gradient over our CWA as it moves closer.
This shortwave will quickly be washed out as it intersects the
building ridge aloft, so we won`t see any precip or really cloud
cover from this- but we`ll see an increase in the winds today,
with gusts up to 20-25 knots possible. A small craft advisory is
in effect for our nearshore zones, as the gusty southwest winds
will lead to choppy conditions. Highs today will be in the 60`s.
Lows tonight will drop into the 40`s. Despite clear skies and our
cooler airmass, stronger winds should keep temps a little warmer
tonight than they were last night.


.LONG TERM...(Wednesday through Monday)
Issued at 332 AM EDT Tue Oct 17 2017

Thanks to our expanding ridge aloft, high pressure will remain in
place through the weekend, with temperatures warming to above normal
for this time of year. Highs will range from the upper 60`s to low-
mid 70`s through the weekend.

Our next chances for precipitation will be Saturday night into
Tuesday. Last night, models agreed on the general plan for
precipitation yesterday but disagreed on the timing. The ECMWF was
slower in bringing the front through than the GFS/GEM. Today we see
the same story-but with slightly different overall timing than
yesterday. Sunday night was the timing from yesterdays run, now we
change to Saturday night-with the main front moving through sometime
Sunday (or Sunday evening if you go with the ECMWF). Significantly
lowered pops from the consensus blend forecast-capping it around 40-
45% due to lower confidence, and kept front timing in between the
two models.

Significant discrepancies arrive on Monday into Tuesday with respect
to the larger-scale patterns, and the associated precipitation
chances. ECMWF has a long wave trough diving over the Great Lakes,
deepening through Wednesday. The GFS has a closed low developing in
the generally same vicinity. Given the disagreement, opted to
stay more in line with the consensus but to lower pops
significantly (from likely to slight chance/chance). While there
is a good chance for precipitation given the upper level patterns,
there is little confidence in the placement of that


.AVIATION...(For the 12Z TAFS through 12Z Wednesday Morning)
Issued at 645 AM EDT Tue Oct 17 2017

Broad sfc ridge centered over the upper OH river will drift into the
Piedmont by Wed morning. As such expect continued a dry subsident
airmass to hold through the lakes within increasing swrly flow. Aftn
breezes will gusts to 20kts during peak mixing this aftn.


LM...Small Craft Advisory from 8 AM this morning to 5 PM EDT this
     afternoon for LMZ043-046.




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