Area Forecast Discussion
Issued by NWS Grand Rapids, MI
Issued by NWS Grand Rapids, MI
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831 FXUS63 KGRR 271945 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 345 PM EDT Thu Jun 27 2024 .KEY MESSAGES... - Chance of showers and storms Friday night into Saturday morning - Cooler and drier late Saturday through Monday - Rain chances increase Tuesday-Wednesday && .DISCUSSION... Issued at 344 PM EDT Thu Jun 27 2024 - Chance of showers and storms Friday night into Saturday morning While the mild weather will continue through the daytime Friday with temps getting back into the upper 70s to low 80s, an elongated mid level trough will bring instability through the region late Friday night into early Saturday. There will be lots of mid level moisture associated with this system. Models have varying timing but high confidence in the feature itself. Strongest flow will be the far southern Michigan with the main focus through Ohio and Pennsylvania. That said, there could be enough shear and instability to overcome any convective inhibition. As such there is a marginal risk for severe weather across lower Michigan south of a line extending from Saginaw Bay to St. Joseph. - Cooler and drier late Saturday through Monday We will have some lingering showers and storms that will be hanging around the area on Saturday. We should see the shower and storm activity from Friday night move out with the low level jet shifting east of the area. The cold front will remain NW of the area until later in the day as it passes through. There will be a bit of instability associated with it due to moisture pooling along the front. However, these situations with the rain and low level jet moving out are not usually conducive for lots of additional convection. Behind the frontal passage by later Saturday, we will see upper ridging and an expansive sfc ridge build toward the area. These features should be well entrenched over the area by Sunday. There will be a cooler and drier flow from the north, helping to clear things out. 850 mb temperatures dropping to +7 to +9C will support highs in the 70s with lower humidity levels. Monday will remain dry as the ridging starts to move east. Temperatures will warm up to around 80 as return flow on the backside of the sfc high shifts east. - Rain chances increase Tuesday-Wednesday It seems that the models and ensembles are locked on to rainfall chances next week being centered on the Tuesday/Wednesday time frame. The details are uncertain as to the exact timing and such. The upper ridge that will be bringing the cool and dry weather to the area Sunday and Monday will shift east of the area by Tuesday. A broad long wave trough will settle in over the Upper Midwest, and provide for a deep flow from the SW for Lower Michigan. We will see a couple of short waves embedded in the flow lift to the NE toward the area. In addition, the low level SSW flow will help to bring a bit of Gulf moisture up and over the area, and with warm and humid conditions. This will provide for showers and storms Tuesday through Wednesday at times. We should see a break in the rain chances for Thursday as the upper trough lifts out of the area, and ridging builds back in temporarily as another trough digs over the western portion of the country. Temperatures will not cool off that much as there is never really a push of cooler air behind the mid-week system. && .AVIATION /18Z TAFS THROUGH 18Z FRIDAY/... Issued at 128 PM EDT Thu Jun 27 2024 VFR conditions are expected to dominate through this forecast period. Only a few wisps of cirrus and a few fair weather cumulus clouds are present at the beginning of this period. This will remain the case until overnight as high clouds will thicken up, and lower to around 10-15k ft agl. This will remain the case through 18z Friday at all sites. Lower clouds and some rain will move in after this forecast period. Winds from the NNW will diminish overnight to less than 5 knots. Winds will then pick up from the SE by Friday afternoon. Some wind gusts can be expected of 18-22 knots Friday afternoon. && .MARINE... Issued at 342 PM EDT Thu Jun 27 2024 Northwest winds peaked this afternoon and continue to diminish. latest webcams show low waves. Waves will continue to diminish tonight as the high builds overhead and winds shift offshore. Models continue to show winds shifting more southerly Friday and building into the late morning to afternoon. These southerly winds will build wave heights early Friday into the afternoon and continue into Friday evening. Conditions will be hazardous to small craft and a beach hazard statement may be needed for this time period as well. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...Small Craft Advisory from noon Friday to 2 AM EDT Saturday for LMZ847>849. && $$ DISCUSSION...NJJ/Ceru AVIATION...NJJ MARINE...Ceru