Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 251817

Area Forecast Discussion
National Weather Service Northern Indiana
217 PM EDT Wed Apr 25 2018

Issued at 628 AM EDT Wed Apr 25 2018

Skies will gradually clear today but it will remain breezy and
cool. High temperatures will range from the upper 40s near lake
Michigan to the lower 60s over eastern Indiana and northwest Ohio.
The rest of the week through the weekend will feature mainly dry
conditions and temperatures averaging a little below normal for
late April. This will change early next week as much warmer air
arrives and temperatures look to climb well into the 70s and
possibly even flirt with 80 degrees to start May.


.SHORT TERM...(This Evening through Thursday)
Issued at 211 PM EDT Wed Apr 25 2018

Quiet weather in the short term as weak surface ridging builds
into the region tonight. Breezy northerly winds this afternoon
will quickly diminish this evening with weakening gradient as high
pressure center moves over the area. With the exception of
residual boundary layer moisture...nearly ideal conditions for
radiational cooling tonight will have lows dropping around 10F
below normal down into the low-mid 30s. Patchy frost and ground
fog will be possible for the early morning hours
Thursday...otherwise a very pleasant day with lots of
sunshine...light winds and near normal temperatures with highs
60-65F. Lake Michigan water temps in the low-mid 40s should have
sufficient land/water thermal gradient in light flow to generate
lake breeze and keep highs only in the upper 40s to lower 50s
close to the lakeshore.


.LONG TERM...(Thursday Night through Wednesday)
Issued at 211 PM EDT Wed Apr 25 2018

A couple of weak disturbances moving through the great lakes
region to begin the long term period. Strong jet dynamics coming
onshore in the Yukon will drive northern stream longwave trough
axis eastward into the great lakes region by Thursday night. A
couple of embedded short waves rotating through the base of this
trough will bring a chance for some light rain Friday and Friday
night. The first disturbance will be competing with a southern
stream wave lifting out of the TN valley up into the Virginia`s
and result in just a slight chance for a shower as associated
surface cold front moves through Friday morning. Second wave digs
a little further south and is accompanied by decent 50-70kt speed
max providing better forcing for precip chances Friday
night...especially northern CWA. A chilly start to the weekend as
high pressure over the western great lakes has our area in CAA on
a breezy NW flow with low level thermal trof bringing 850mb temps
down to -6C. Expect a pronounced lake shadow on temps with highs
only in the mid-upper 40s near the lake and SBN only near 50F.
Ridge axis shifts eastward over our area Saturday night and will
have lows dropping close to freezing as conditions favorable for
strong radiational cooling. Closed upper low moving onshore this
weekend will establish western US trough and building ridge over
the Rockies and plains Saturday. Ridging and subsequent height
rises spread eastward over our area Sunday into Monday and sets
the stage for a nice warmup into the 70s beginning of next week.
Energy ejecting out of western trof will push surface boundary
toward our area and bring precip chances back by the end of the


.AVIATION...(For the 18Z TAFS through 18Z Thursday Afternoon)
Issued at 100 PM EDT Wed Apr 25 2018

VFR through the period with northerly winds diminishing to light
and variable overnight. Patchy ground fog possible early morning
hours Thursday but no aviation impacts expected.


LM...Small Craft Advisory until 2 AM EDT Thursday for LMZ043-046.




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