Area Forecast Discussion
Issued by NWS Grand Rapids, MI
Issued by NWS Grand Rapids, MI
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104 FXUS63 KGRR 170747 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 347 AM EDT Mon Jun 17 2024 .KEY MESSAGES... - Heat Advisory For Most Of Our Area Today - Friday - A Few Showers and Storms Today - Heat and Humidity Continue Through Mid to Lake Week - Small Chances for Precipitation Mid Week - Cooler Weather Behind a Cold Front Next Sunday && .DISCUSSION... Issued at 347 AM EDT Mon Jun 17 2024 - Heat Advisory For Most Of Our Area Today - Friday It will be hot and humid today and again on Tuesday with persistent southerly flow waa and as h8 temps moderate to 20 C. This in conjunction with the amplifying upper ridge over the eastern CONUS as h5 heights reach around 590 dM over our area will result in high temps reaching into the lower to perhaps middle 90s today and tomorrow. This combined with dew pt values in the upper 60s to lower 70s will result in heat indices reaching around 100 this afternoon and early evening and again tomorrow. We have decided to issue a heat advisory for most of our area as a result. Thx for extensive coord on headline decisions DTX/IWX/APX. - A Few Showers and Storms Today Rain and thunderstorms are still in progress early this morning over our se fcst area tied to the mcv that is moving slowly east across that area. Severe wx potential has subsided overnight but there is still potential for localized flooding given slow movement of this precipitation across the same areas. We expect pcpn to taper off over our se fcst area toward daybreak with mostly dry conditions from mid to late morning into the afternoon. A few showers and convection will likely redevelop this afternoon with instability from daytime heating and perhaps in the vicinity of boundaries from this early morning activity. - Heat and Humidity Continue Through Mid to Lake Week Heat and humidity look to continue mid to late week and likely into Saturday as well. The upper level ridge actually builds into the Southern Great Lakes mid to late week with 590+ dm 500mb heights. 850mb temperatures are not overly warm, but are largely in the +18C to around +20C range. These values should push surface high temperatures to around 90 or into the lower 90s from Wednesday through Saturday. Surface dew points in the upper 60s to around 70 should push heat index values towards 100 at times through the Wednesday through Saturday time frame. Heat Advisory looks good at least through Friday. A prolonged heat event for sure. - Small Chances for Precipitation Mid Week There are small chances that we may see some shower and thunderstorm activity spill into the forecast area at times, with the best of those chances being Wednesday night into Thursday. It is this time frame that a boundary sags into the area from the north. Both the operational GFS and ECMWF show some activity making inroads into the region. Do not think this will be an all day all night type of event though and feel the headlines are still warranted this far out. Could see the stout ridge winning out though and the better bet is we will likely stay dry. - Cooler Weather Behind a Cold Front Next Sunday The heat at humidity that really began yesterday (Sat the 16th) will likely stretch all the way to Saturday the 22nd. It is not until Sunday when a pattern change occurs with an upper low pushing into the Great Lakes along with a surface cold front. Models are fairly consistent that the cold front will move through on Sunday. Sunday night lows dip back into the 50s in parts of the area. && .AVIATION /06Z TAFS THROUGH 06Z TUESDAY/... Issued at 110 AM EDT Mon Jun 17 2024 Lingering showers and thunderstorms at our southeast terminals at the moment will gradually end during the next few hours. Primarily VFR conditions are then expected at the terminals overnight but some patchy MVFR fog will develop toward daybreak. Any patchy fog will burn off by mid morning with VFR conditions expected for the rest of the day. Isolated showers and thunderstorms are possible in the afternoon and evening but there is not enough potential or confidence in timing to warrant mention in the terminal forecasts at this time. && .MARINE... Issued at 347 AM EDT Mon Jun 17 2024 Winds and waves will remain below sca criteria early this week. Southerly winds to around 15 to 20 kts will build wave heights to around 2 to 4 feet across our northern nearshore zones with lower wave heights further south. Isolated thunderstorms could pose a hazard to mariners. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...Air Quality Alert until midnight EDT tonight for MIZ037-043-050- 056-064-071. Heat Advisory from noon today to 8 PM EDT Friday for MIZ043>046- 050>052-056>059-064>067-071>074. MARINE...None. && $$ DISCUSSION...Duke/Laurens AVIATION...Laurens MARINE...Laurens