Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 172335
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
735 PM EDT Thu Oct 17 2019

.SYNOPSIS...
Issued at 120 PM EDT Thu Oct 17 2019

A Frost Advisory is in effect for most areas tonight. As skies
clear and winds drop off, expect frost to form before daybreak
Friday. Warmer and continued dry Friday and Saturday. Lows tonight
will drop to near freezing in most locations. Highs in the middle
50s to lower 60s Friday and lower to middle 60s Saturday.

&&

.SHORT TERM...(This Evening through Friday)
Issued at 211 PM EDT Thu Oct 17 2019

Latest surface analysis has ridge axis over the mid MS valley as
deep low has moved off to the NE US. Weak short wave depicted on
water vapor imagery moving down through the western great lakes in
NW flow aloft. Continued drying of boundary layer and clearing
skies expected tonight as ridge axis moves overhead. This has
current forecast on track for widespread frost over much of the
area by early morning hours Friday as lows dip down toward the
freezing mark. Quiet weather day on tap for Friday as surface high
pressure slides to the east and brings a more southerly flow on
the backside by the afternoon. Decent low level WAA combined with
upper level ridging will have temps recovering closer to normal
with highs in the upper 50s to lower 60s.

&&

.LONG TERM...(Friday Night through Thursday)
Issued at 211 PM EDT Thu Oct 17 2019

Low pressure in the western gulf of Mexico will ride along
stalled frontal boundary Saturday to limit return moisture
associated with northern stream system moving across southern
Canada that will drag weak frontal boundary across the area
Saturday night. Upper level forcing will be detached well to the
north with parent surface low to further limit precip potential so
see no problem staying with current forecast that limits POPs to
low chance. Warming trend continues ahead of this system with low
level thermal ridge bringing 850mb temps to 10C Saturday afternoon
and resulting highs 65-70F. Meanwhile stronger system developing
in the plains this weekend will lift out and affect the area
beginning of next week. Closed upper low will move northward into
SW Ontario Monday night and bring potent mid-upper level support
into our area as 75kt+ mid level speed max will be accompanied by
140kt+ upper jet. Even strongest outlier amongst enemble members
just under 500J/kg of CAPE and mean around 100J/kg so an otherwise
favorable unidirectional wind profile for damaging wind potential
may have insufficient instability to work with. Dry forecast
behind this system for Wednesday but with fast moving quasi-zonal
flow may have another system moving across the region by day 7 but
will stay with dry forecast for now. No significant cold air
behind this system but temps will trend back below normal.

&&

.AVIATION...(For the 00Z TAFS through 00Z Friday Evening)
Issued at 733 PM EDT Thu Oct 17 2019

Overnight, stratus continues to break up as shortwave dives southeast
away from our area and subsidence occurs allowing a good low
level inversion as noted in forecast soundings. With the cool air
continuing to stream over the warmer lake waters, SBN may hold
onto MVFR for a few more hours with clouds continuing to form, but
do think it eventually improves to VFR during the overnight. Wind
gusts will be able to relax with high pressure overhead and a
loosening pressure gradient.

High presure pushes east of the area Friday keeping the area in
VFR conditions and with light winds. However, the winds should
veer ending up out of the south by the end of period after
starting out, out of the northwest.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...Frost Advisory from 2 AM EDT /1 AM CDT/ to 9 AM EDT /8 AM CDT/
     Friday for INZ004>009-012>018-020-022>027-032>034.

MI...Frost Advisory from 2 AM to 9 AM EDT Friday for MIZ078>081.

OH...Frost Advisory from 2 AM to 9 AM EDT Friday for OHZ001-002-004-
     005-015-016-024-025.

LM...NONE.
&&

$$

SYNOPSIS...Lewis
SHORT TERM...JAL
LONG TERM...JAL
AVIATION...Roller


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