National Weather Service Raw Text Product
Displaying AFOS PIL: AFDIWX Received: 2017-10-18 08:03 UTC
Previous in Time Latest Product Next in Time
View All KIWX Products for 18 Oct 2017 View All AFD Products for 18 Oct 2017 View As Image Download As Text
209 FXUS63 KIWX 180803 AFDIWX Area Forecast Discussion National Weather Service Northern Indiana 403 AM EDT Wed Oct 18 2017 .SYNOPSIS... Issued at 359 AM EDT Wed Oct 18 2017 Another pleasant day is in store today as high pressure lingers over the area. Mostly sunny skies will give way to high temperatures in the upper 60's and low 70's. Lows tonight will be primarily in the upper 40's. Quiet weather will continue through Saturday, with temperatures warming to well above normal. Highs through the rest of the week will range from the upper 60's to the mid-upper 70's. && .SHORT TERM...(Today and Tonight) Issued at 359 AM EDT Wed Oct 18 2017 As they say, "big bubble no trouble" for the short term. High pressure remains at the surface with a building ridge aloft. 850mb temps rise to the 10-12C range through Thursday, which keeps our high temperatures in the upper 60's and low 70's, and overnight lows in the 40's. Low pressure swinging through northern ontario will cause a brief increase in the pressure gradient, and thus it will be a bit breezy this afternoon-especially near Lake Michigan. A small craft advisory is in effect for the nearshore waters as gusts will be near 22-25 knots and waves will build to 3 to 4 feet. && .LONG TERM...(Thursday through Tuesday) Issued at 359 AM EDT Wed Oct 18 2017 A couple of interesting topics to discuss for the long term forecast, with chances for rain starting Saturday night associated with a frontal boundary, and perhaps a few Lake effect rain showers Tuesday into Wednesday.Thankfully, models are closing in on timing for the frontal passage on Saturday night-Sunday. Given the reasonable output and general agreement during this time frame, have allowed the consensus chance to likely pops to remain. Kept chance pops through Monday-though they may be slightly overdone (especially between 06-12Z). In actuality there may be a break in precipitation before the secondary front arrives, but I kept them given the uncertainty of the timing. If the first front takes longer to exit, and then the second lags a little slower as the GFS suggests we could have some lingering precipitation to deal with. Where things begin to differ significantly is Monday afternoon- mainly due to the differences with how the models handle the secondary trough to our north. The ECMWF is much deeper, and brings the trough through Monday afternoon- developing a closed low over the eastern Upper Peninsula of Michigan. It then drags the low across the Great Lakes through Wednesday, bringing a touch of colder air in its wake (thus some chances for lake effect rain showers Tue-Wed). However, the GFS is slower to develop this deeper trough and bring it through-and it differs in strength/location from the ECMWF. This would put a larger gap in between precipitation batches-keeping things dry all day Monday and early Tuesday. The one thing that both models have in common, despite the variances in location-is that they develop a long north- northwesterly fetch across Lake Michigan by Tuesday night and Wednesday. Of course, given decent instability on Lake Michigan from the falling temperatures, synoptic forcing aloft with the upper low, and enough moisture to work with-think that the probability of seeing some sort of Lake Effect band (rain) is high Tuesday night into Wednesday. Kept the higher probabilities where I felt it was most likely based on the current forecasted wind direction. Of course with any lake effect it's uncertain where any one band would develop, but given the pattern and time of year it's a pretty good chance it will play out. We'll see how it evolves over the next few days. Otherwise, we'll keep above normal temperatures through Sunday, with high temperatures reaching as high as the mid-upper 70's on Friday- Saturday (especially in the far southwest). Temps for the remainder of the weekend and the start of next week are a little trickier-as we are not confident on the general timing of that secondary front- which has substantially colder air behind it. Leaned on the colder side for Tuesday/Wednesday per collaboration with surrounding offices and earlier shifts, given the pattern is typically one we see with the colder, rainier conditions. For now, I have highs in the low-mid 50's for both days, with lows in the 40's. && .AVIATION...(For the 06Z TAFS through 06Z Wednesday Night) Issued at 1234 AM EDT Wed Oct 18 2017 VFR conditions to prevail through the period and beyond. Mixing of somewhat stronger wind fields aloft will occur once inversion is lost with some gusts near 20 kts. Quick loss of gustiness will occur after 00Z. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...Small Craft Advisory from 10 AM this morning to 4 AM EDT Thursday for LMZ043-046. && $$ SYNOPSIS...MCD SHORT TERM...MCD LONG TERM...MCD 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