Area Forecast Discussion
Issued by NWS Northern Indiana

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818
FXUS63 KIWX 261026
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
626 AM EDT Mon Sep 26 2016

.SYNOPSIS...
Issued at 344 AM EDT Mon Sep 26 2016

A cold front will swing through this morning bringing a period of
rain. Breezy and mostly sunny conditions can be expected by this
afternoon as much drier and cooler air overspreads. Temperatures
today will generally hold in the 60s. Dry and cool conditions
will persist into tonight and Tuesday before an upper low brings
renewed rain chances and mainly cloudy skies Tuesday night into
Wednesday. Highs on Wednesday are forecast to only reach the low
to mid 60s.

&&

.SHORT TERM...(Today through Tuesday)
Issued at 344 AM EDT Mon Sep 26 2016

Shortwave trough taking on a negative tilt into the northwest Great
Lakes will invoke a frontogenetical response along the mid level
portion of cold front/moisture axis working east through the
region this morning. The result should be a blossoming, yet
narrow, area of rain which should exit our IN/MI zones by mid
morning and nw OH midday. Weak instability may support some
embedded thunder, best chances along/east of I-69 near sfc portion
of front.

Pronounced dry slot and post-frontal cold advection will provide a
trend toward mostly sunny skies and gusty winds (20-25 knots)
from west to east later this morning/afternoon, with sfc ambient
temps holding in the 60s. Dry westerly flow is then expected to
persist into tonight and Tuesday as main PV filament and mid-
upper level jetlet lifting through the Great Lakes deepens low
pressure just north of Lake Superior, which then becomes
vertically stacked by Tuesday. Winds will relax tonight but once
again become somewhat gusty during the day Tuesday given ample
sunshine and tight low level height gradient.

&&

.LONG TERM...(Tuesday Night through Sunday)
Issued at 344 AM EDT Mon Sep 26 2016

Clouds and shower chances return later Tuesday night into Wednesday
as deep tropospheric circulation drops in. Last several model cycles
have trended more aggressive with deep/smaller scale PV anomaly and
added lake response (stronger low level troughing) into the lower
Lakes later Tuesday night/Wednesday morning. Have increased
PoPs/QPF as a result, especially closer to Lake MI. Clouds/pcpn
should limit the diurnal temp response with highs Wednesday only
reaching the upper 50s to mid 60s.

The GFS/GEM have unfortunately come more inline with the ECMWF in
cutting off the upper low either overhead or just east of the area
Thursday through at least Saturday. Have increased Sky cover,
lowered the diurnal temp ranges a few degrees, and added a low
PoP each day to account for these trends.

&&

.AVIATION...(For the 12Z TAFS through 12Z Tuesday Morning)
Issued at 626 AM EDT Mon Sep 26 2016

Brief/transient mvfr restriction near term invof both terminals as
post frontal rain shield rapidly shifts ne. Otherwise vfr with abrupt
clearing expected mid to late morning in concert with deepening
subsidence aloft and strong low level caa/drying. Ramping mixed
layer no doubt accentuated by solar insolation will drive gusty west
winds to 25 knots this afternoon.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...Small Craft Advisory until 11 PM EDT Wednesday for LMZ043-046.

&&

$$

SYNOPSIS...Steinwedel
SHORT TERM...Steinwedel
LONG TERM...Steinwedel
AVIATION...T


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