Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 151554

Area Forecast Discussion
National Weather Service Northern Indiana
1154 AM EDT Fri Sep 15 2017

Issued at 248 AM EDT Thu Sep 14 2017

Mostly sunny to partly cloudy skies will persist today allowing
highs to reach the upper 70s to lower 80s. Temperatures will
continue to warm into the weekend with highs in the lower to mid
80s. The next chance of showers and a few thunderstorms will
arrive for Sunday afternoon into Sunday night.


Issued at 1145 AM EDT Fri Sep 15 2017

Fog has diminished this morning, with quiet weather for the
remainder of the afternoon. Best stratocu coverage is expected to
develop across east/southeast portions of the forecast area, but
most locations are expected to remain mostly sunny. Previous
forecast in good shape with highs 75-80 with coolest temps across
far southeast where greatest coverage low clouds are expected.
Patchy shallow fog may develop again tonight, particularly across
extreme northeast Indiana/northwest Ohio. Early indications
suggest this threat will not be as widespread as past few nights
and confined mainly to northwest Ohio/south central Lower


.SHORT TERM...(Today and Tonight)
Issued at 248 AM EDT Fri Sep 15 2017

Main focus will be fog coverage and possible impacts on the
morning commute.

Thus far, a handful of observation sites have shown brief drops in
visibility from what is likely rather shallow ground fog. 7Z obs
showed 3 sites in the quarter to half mile range. Most locations
were now at or below their crossover temperatures in the upper 50s
to lower 60s, suggesting that fog may begin to increase in
coverage over the next several hours. Past grids had patchy fog
mentioned NW third with areas of fog after 9Z in SE 2/3rds of the
area. See no reason to deviate for now and potential for dense
fog still exists. No headlines will be issued at this time, but
may be needed over the next couple of hours.

Any fog should dissipate quickly Friday morning with the
continuation of above normal temperatures in store. Somewhat
warmer overnight lows Friday night and a slight increase in
boundary layer winds should reduce fog potential for the area.


.LONG TERM...(Saturday through Thursday)
Issued at 248 AM EDT Fri Sep 15 2017

Above normal temperatures look to dominate the period as trough to
the west digs into the plains and generally remains west of the
region. A weak cool front will attempt to pass through the area
with a chance of showers (thunder?) Sun afternoon into Sunday
night. Models agree on this eventually washing out Monday with
trough digging even further. Weak ripples in the trough could
bring sporadic shower chances to the area into the middle of the
week as dewpoints reach into the 60s providing at least some
limited instability for the waves to interact with. With the
longwave pattern not set to modify much, no more than slight chc
to chc pops warranted at this point.


.AVIATION...(For the 12Z TAFS through 12Z Saturday Morning)
Issued at 608 AM EDT Fri Sep 15 2017

Mvfr/ifr visibilities in br/fg at most airports around the area
early this morning, but so far not at sbn/fwa. Temps at the
terminals have fallen several degrees below crossover temp, though
appears moisture may be shallow enough to prevent sgfnt vsby
restrictions. Plan to cont with current tafs mention of brief
tempo mvfr vsby restrictions at sbn and ifr at fwa early this
morning. No vsby restrictions and just sct cu expected the rest of
the day. Shallow moisture will remain in place tonight, but
gradient winds should be a bit stronger, so left tafs vfr for now.




LONG TERM...Fisher

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