Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 271625

Area Forecast Discussion
National Weather Service Northern Indiana
1225 PM EDT Tue Jun 27 2017

Issued at 345 AM EDT Tue Jun 27 2017

High pressure will build across the area today resulting in fair
weather. As the high pressure system moves east Wednesday, southerly
winds will develop over our area leading to warmer and more humid
conditions. A frontal system will drop slowly southeast across the
area Thursday and Friday bringing periodic chances for showers and


.SHORT TERM...(Today through Tonight)
Issued at 345 AM EDT Tue Jun 27 2017

Ridging sfc and aloft will build across the srn lakes this period
with tranquil wx as a result. Much less cloud cover this aftn within
weakening low level thermal trough will result in slightly warmer
temps vs yesterday.


.LONG TERM...(Wednesday through Monday)
Issued at 345 AM EDT Tue Jun 27 2017

Rapid temp moderation to start the period on Wed as sfc ridge
quickly shifts off through the ern OH valley ahead of sw trough and
attendant frontal zone progressing through the nrn plains. Deep
mixing within wrn periphery of stronger low level warm
advection/more robust thermal ridging will propel temps back into
the low 80s west to upper 70s east. Low level moisture return tepid
at best with far better forcing overlapping more sig low level theta-
e ridging lining up across ern IA/wrn IL and see no need to hold
onto slight chc pops nw Wed aftn.

Thereafter unsettled pattern aloft sets up across the lakes as
frontal zone stalls within initial flat wrly flow aloft. Lead nrn
plains disturbance will excite a pronounced warm advection wing Wed
night as upper wave temporarily closes off over the nrn lakes and
prior grids still fit well with latest 00Z progs. Otherwise a period
of mid level subsidence in wake of lead sw likely to follow Thu am
and will cut back from prior gridded pops. Regardless favorable
diurnal destabilization expected Thu aftn and with frontal
boundary...perhaps composited in with leftover the
vicinity should trigger sct storms late aftn/evening. Will modify
blended guidance to favor nrn zones for higher pops including Thu
evening ahead of resurging low level jet ahead of next upstream
potent nrn plains sw amplifying sewd across the dakotas.

Otherwise vigorous frontal wave and attendant cold front will across
the wrn lakes late Fri with widespread storms expected.


.AVIATION...(For the 18Z TAFS through 18Z Wednesday Afternoon)
Issued at 1220 PM EDT Tue Jun 27 2017

The surface high pressure area will shift east tonight, allowing
return flow to begin. By 14Z, winds should be south at 10-15
knots; otherwise, conditions will remain VFR.





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