Area Forecast Discussion
Issued by NWS Northern Indiana

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000 FXUS63 KIWX 281959 AFDIWX Area Forecast Discussion National Weather Service Northern Indiana 359 PM EDT Wed Sep 28 2016 .SYNOPSIS...
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Issued at 337 PM EDT Wed Sep 28 2016 A slow moving upper level disturbance will persist across the region through the first part of the weekend. This will lead to periodic scattered rain showers through Saturday. Isolated thunderstorms will also be possible each afternoon through Friday. Mainly dry conditions are then expected for the second half of the weekend. Low temperatures tonight will drop into the lower to mid 50s. High temperatures on Thursday will reach into the mid to upper 60s.
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&& .SHORT TERM...
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(This Evening through Thursday) Issued at 337 PM EDT Wed Sep 28 2016 Unsettled weather pattern to continue into at least first half of the weekend as meandering upper low will persist across the region. A series of disturbances will continue to rotate through broad upper low level, with center of parent circulation centered across northwest Indiana this afternoon. One of these short waves appears to be nosing across north central Indiana at this time. DPVA associated with this short wave combined with low level convergence along low level trough axis has led to some renewed convection across central Indiana into far south central portions of the forecast area this afternoon. As this wave continues to progress through parent circulation, low level cyclonic circulation axis will gradually reorient more in a northwest to southeast fashion across central portions of the forecast area. DPVA should also begin to increase as aforementioned vort max wraps northward across the southern Great Lakes. Given above evolution and establishment of cold pool aloft, have maintained trend to scattered-numerous PoPs across approximately northern half of the area by late afternoon/early evening. Did maintain these mid range PoPs through the night, especially north half, as low/mid level moisture axis wraps cyclonically across the southern Great Lakes. Have maintained isolated thunder mention through early evening, mainly across the southeast half where axis of 100-300 J/kg MLCAPES should reside. Some small hail will continue to be a possibility through late this afternoon, particularly southeast half of the area. Persistent cloud cover and moist air mass will limit diurnal temp ranges tonight, and have maintained lows in the lower to mid 50s. A similar setup appear to be in store for Thursday as upper low drops across the lower Ohio Valley. Upper speed max and associated short wave rotating through the base of this trough across mid MS Valley will begin to impact the area on Thursday with a renewed chance of showers/iso storms. Orientation of more favorable deeper moisture axis should support highest (likely) PoPs across the northern half. Maintenance of steep low level lapse rats will make thunder possible once again Thursday. Some small hail cannot be ruled out given proximity of cold core aloft, but freezing levels should be slightly higher on Thursday.
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&& .LONG TERM...
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(Thursday Night through Wednesday) Issued at 337 PM EDT Wed Sep 28 2016 Chance of showers will continue Thursday night, although have maintained somewhat lower chances for this period as some lull in stronger forcing is expected. Yet another stronger vort lobe will lift northeast through upper trough late Thursday night into Friday causing mid/upper level height minimum to lift back northward on Friday. Previous forecast already had likely PoPs for Friday and see no reason to deviate at this time. Lapse rates may not be quite as steep on Friday but plentiful moisture should result in enough weak instability for iso thunder mention in the afternoon. Scattered showers will likely persist into Saturday as upper low lifts across the southern Great Lakes. This feature should eventually get ingested by an upper level PV anomaly dropping out of southeast Canada, resulting in diminishing rain chances by Saturday night/Sunday. Moderating trend then expected for early next week with highs back into the mid 70s by Tuesday. Another chance of rain appears to be in store toward and just beyond this forecast period due to next approaching front.
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&& .AVIATION...
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(For the 18Z TAFS through 18Z Thursday Afternoon) Issued at 141 PM EDT Wed Sep 28 2016 Low confidence in evolution of flight restrictions and shower activity associated with upper low currently south of KSBN. Many of the Hi Res models suggested a lull in activity late AM into early PM with a uptick in convection during the afternoon and evening hours. This uptick may be underway across central Indiana but impacts on KFWA are far from certain. In addition, models also suggest large area of rain in SW Ohio will pivot back into the area this evening and impact parts of the area. Lower cigs are found west of the upper low circulation with VFR conditions elsewhere. Given southern track of the low may take some time for lower ceilings to work in with KFWA still possibly seeing them sooner. Minor changes to TAFs at both sites with spirit of downward trend still kept. Additional changes will be required in later forecasts.
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&& .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...Small Craft Advisory until 8 AM EDT Friday for LMZ043-046. && $$ SYNOPSIS...Marsili SHORT TERM...Marsili LONG TERM...Marsili AVIATION...Fisher Visit us at www.weather.gov/iwx Follow us on Facebook...Twitter...and YouTube at: www.facebook.com/NWSNorthernIndiana www.twitter.com/nwsiwx www.youtube.com/NWSNorthernIndiana

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