Area Forecast Discussion
Issued by NWS Grand Rapids, MI
Issued by NWS Grand Rapids, MI
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159 FXUS63 KGRR 161159 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 759 AM EDT Sun Jun 16 2024 .KEY MESSAGES... - Excessive Heat Watch For Most of our Area Monday - Friday - Low Risk for Showers and Isolated Storms Today - Heat and Humidity To Continue Through the Work Week - Much of the Upcoming Week Trending Towards Dry Weather && .DISCUSSION... Issued at 348 AM EDT Sun Jun 16 2024 - Excessive heat watch for most of our area Monday - Friday It will become very hot and humid Monday as upper level ridging strengthens and h8 temps moderate to around 20 C. This in conjunction with southerly flow waa and ample sun with 500mb heights reaching near 590dm will result in high temps reaching the low to mid 90s for much of our area tomorrow. This along with with dew pt values reaching the upper 60s to lower 70s will yield heat indices which will approach the 100 degree mark tomorrow afternoon. Thx for extensive coord on the excessive heat watch headline IWX/DTX/APX. - Low risk for showers and isolated storms today Increasing moisture and an upper disturbance in conjunction with weak instability will result in scattered showers and isolated convection mainly north of the I-96 corridor today as suggested by the 00Z HREF and to some extent our latest CAMs. Otherwise dry wx will prevail for much of the day and it will become hotter with high temps reaching the middle to upper 80s. - Heat and Humidity To Continue Through the Work Week We continue to be concerned with the heat and humidity through the work week and potentially into next weekend as well. We are leaning more on the ECMWF guidance as it has been consistent with the persistent warmth. The GFS has trended warmer with higher 500mb heights with each model run. Evening 850mb temperatures each day this week are between +19C and +21C over GRR. This should yield high temperatures in the lower 90s. When combined with dew points that should be in the upper 60s to around 70 we should have heat index values approaching 100 degrees each day this week. For that reason the Excessive Heat Watch was issued. The cumulative affect of many days of that kind of heat with no relief at night (lows in the 70s) will take its toll, especially on folks without air conditioning. We did not issue for the U.S. 10 row at this point but they may need to be added in as well. Each shift going forward will reevaluate the heat headlines. The current configuration was what we were most comfortable with at this point. Coordinated headlines will all neighboring offices. 500mb heights are impressive with both the GFS and ECMWF showing 590s dm heights the majority of the week. The surface boundary in the ECMWF has trended further northwest in the early to mid week time frame which should keep us more on the sunny side of the ledger. Bottom line, it is going to be a hot and humid week and we will need to check in on folks without air conditioning. People that work outdoors will need to take frequent breaks and drink plenty of water to stay hydrated. - Much of the Upcoming Week Trending Towards Dry Weather Given the high heights and warm mid level temperatures we are becoming less concerned with chances for clouds and precipitation. The one day possibly that we could see precipitation is Thursday as the boundary that was off to our north sags in. The boundary is very much losing definition though and washing out with time as the ridge is dominant. Much if not all the week is looking dry though. Mid summer heat and humidity with little in the way of precipitation is the weather story. && .AVIATION /12Z TAFS THROUGH 12Z MONDAY/... Issued at 758 AM EDT Sun Jun 16 2024 VFR weather is in place across Southwest Lower Michigan at 12Z, while showers and thunderstorms are moving east across Wisconsin. The question is how much if any of this activity makes it into our area later this morning and afternoon. Our feeling at this point is much of if not all of the activity will remain northwest of the TAF sites today. The clouds today will be of the mid and high variety with bases at or above 8,000 feet for the most part. Tonight we may see some shower and thunderstorm activity spill into Central Lower Michigan from the north, but this will also largely miss the TAF sites. Winds today will be gusty out of the south at 15 to 25 knots. && .MARINE... Issued at 348 AM EDT Sun Jun 16 2024 A small craft advisory and beach hazards statement is in effect from Grand Haven northward through late tonight. South winds will continue to increase today to near 30 kts at times. This will cause wave heights to build to around 4 to 6 feet from Grand Haven northward. Winds and waves will subside a bit very late tonight and Monday. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...Beach Hazards Statement through late tonight for MIZ037-043-050- 056. Excessive Heat Watch from Monday afternoon through Friday evening for MIZ043>046-050>052-056>059-064>067-071>074. MARINE...Small Craft Advisory until 2 AM EDT Monday for LMZ847>849. && $$ DISCUSSION...Duke/Laurens AVIATION...Duke MARINE...Laurens