645 FXUS63 KGRR 080518 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 118 AM EDT Fri Oct 8 2021 LATEST UPDATE... Aviation .SYNOPSIS... Issued at 330 PM EDT Thu Oct 7 2021 -Showers and a few storms through Saturday -Very warm and mainly dry Sunday into Monday, breezy -More showers and storms Mon ngt/Tues, still warm next week && .DISCUSSION...(This evening through next Thursday) Issued at 330 PM EDT Thu Oct 7 2021 -Showers and a few storms through Saturday Occasional showers and a few tstms can be expected through Saturday as a large/closed upper low currently near St Louis moves slowly northeast. The low will be near Chicago on Friday before drifting across Lwr MI as a negatively tilted/open wave on Friday night into Saturday. PWATS of around 1.5 inches (quite high for early October) are associated with this system so locally heavy rainfall is a possibility. Some narrow swaths of over 1.5 inches could develop per HREF guidance and if any of those overlap the localized heavy swaths from the previous event some minor flooding could occur. The best coverage/intensity of convection will probably occur on Friday afternoon and evening as the upper low is approaching and when instability is diurnally peaking. Around 1000 J/KG of sfc based cape is progged at 21Z Friday, with a better chance of a few breaks in the cloud cover than today. In addition to the threat of torrential downpours, a few funnel cloud reports cannot be ruled out in low LCL/upper low environment. The wave clears most of southwest lwr MI by 18Z Saturday, but associated widely scattered convection on it's wrn periphery may still impact the northeast and east portion of the GRR CWFA into early Saturday evening. -Very warm and mainly dry Sunday into Monday, breezy In the wake of the departing wave, deep southwesterly flow ahead of deep wrn U.S. trough sends unseasonably warm air into Michigan. Temperatures as much as 20 degrees above normal are expected, with highs on Sunday and Monday potentially topping 80 degrees. This isn't too far off from the record highs which are in the lower to mid 80s. (See the climate section below for the specifics.) Record high minimum temps could also be in jeopardy. We'll be inbetween waves on Sunday and Monday, and while the chance of rain isn't zero, believe most of the time it will be dry. The low level jet being overhead will lead to breezy days with gusts of 25-30 mph out of the south. -More showers and storms Mon ngt/Tues, still warm next week The next wave coming out of the wrn U.S. trough looks to arrive here late Monday into Monday night, lifting out on Tuesday afternoon. This wave should offer another good chance of showers and tstms, but very little chance of any noteworthy cool down in it's wake as the deep wrn trough persists. Confidence is high that temperatures will continue to average above to much above normal through most of next week. && .AVIATION...(For the 06Z TAFS through 06Z Friday night) Issued at 118 AM EDT Fri Oct 8 2021 Widespread LIFR stratus clouds are in place, with some light MVFR fog across the area. There are a few isolated breaks, but the fog satellite imagery shows the extensive cloud cover pretty well. This will continue through sunrise, before the conditions will slowly improve late this morning and this afternoon. We expect a few scattered showers will start to develop around the terminals toward and after about 09z this morning. Can not rule out a rumble of thunder, but the instability will be fairly limited early. Showers and storms will develop with the heating of the day and the wave moving overhead. The best chance of lightning/thunder will be after 18z and prior to 00z. Rain showers will likely gradually come to an end later this evening. We do not expect fog and stratus to be an issue tonight with the area being behind the low and drier air trying to move in. && .MARINE... Issued at 330 PM EDT Thu Oct 7 2021 Main focus for Lake Michigan is the potential for a strong southerly flow event beginning Saturday night and continuing Sunday, and possibly even into Monday as well. A Small Craft Advisory will likely be needed during this time, with the highest waves being north of Holland. Until then, winds and waves remaining on the lower side but a risk for ocnl tstms, torrential downpours, and patchy dense fog. && .CLIMATE... Issued at 330 PM EDT Thu Oct 7 2021 Record Highs for 10/10 (Sunday): GRR...85 in 1949 LAN...83 in 1879 MKG...84 in 1913 AZO...87 in 1938 Record Highs for 10/11 (Monday): GRR...85 in 1928 LAN...84 in 1879 MKG...81 in 1973 AZO...84 in 1962 && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. LM...None. && $$ SYNOPSIS...Meade DISCUSSION...Meade AVIATION...NJJ CLIMATE...Meade MARINE...Meade