Area Forecast Discussion
Issued by NWS Northern Indiana

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49

FXUS63 KIWX 211753

Area Forecast Discussion
National Weather Service Northern Indiana
153 PM EDT Sun May 21 2017

Issued at 130 PM EDT Sun May 21 2017

A cold front and collocated showers exit the region during the
afternoon allowing for some breaks in the clouds heading into
tonight. Dry conditions are expected tonight and Monday as high
pressure moves into the region. However, another low pressure
system returns for Tuesday and Wednesday resulting in showers and
possibly some thunder. Rain is still possible Thursday, but to a
lesser extent as the system finally exits the area. Lows tonight
will be able to fall into the upper 40s, but highs will rebound
into the upper 60s to low 70s on Monday and Tuesday. Wednesday and
Thursday will have below normal highs only reaching the mid to
upper 60s before temps finally rebound into the 70s and possibly
into the 80s for the weekend.


Issued at 1042 AM EDT Sun May 21 2017

Update issued to more succinctly capture narrow frontally forced
convection. So far relatively shallow cells, quite limited
pulse/flash activity past hour, however additional modest
upstream destabilization along with 40-50m/12 hour height falls
should be sufficient to get increase in depth for more potential
isolated lightning flashes. Wrap around moisture progressively
filling in across northeast IL and will increase cloud coverage
with a partial blend towards latest hi-res model trends. Quick
eastward progression of the linear convection/cloud coverage
requiring downward trend to temps as well.


.SHORT TERM...(Today and Tonight)
Issued at 454 AM EDT Sun May 21 2017

The cold front will move across the area today, bringing an end to
the showers and storms. Some storms are possible, but the storms are
not expected to reach severe limits given limited instability.
Little additional rainfall is expected over the areas that had
heavier rain last night.


.LONG TERM...(Monday through Saturday)
Issued at 454 AM EDT Sun May 21 2017

After a break in the rainy weather Monday, another round of rain is
expected during the middle of the week as a strong impulse drops
into the long wave pattern over eastern North America. For this
package, have favored a GFS solution of an upper low cutting off
around or north of the Ohio River Wednesday night. Rainfall
amounts from this next system could range from half an inch to an
inch and a half by Thursday morning. It looks like temperatures
will be held in the low 60s Wednesday given clouds and rain. The
upper level winds should become more southwest by late in the week
and allow temperatures to rise well into the 70s and possibly
into the 80s this upcoming weekend.


.AVIATION...(For the 18Z TAFS through 18Z Monday Afternoon)
Issued at 130 PM EDT Sun May 21 2017

Cold front pushes out of the area during the afternoon changing
wind direction, scouring out moisture and allowing for some wind
gusts this afternoon. Conditions are back into VFR for this
afternoon. However, will have to watch a 700mb trough move through
between 00z and 06z tonight for a reduction back to MVFR before
conditions improve to VFR again for Monday.




SHORT TERM...Skipper
LONG TERM...Skipper

Visit us at

Follow us on Facebook...Twitter...and YouTube at: is the U.S. government's official web portal to all federal, state and local government web resources and services.