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Area Forecast Discussion
Issued by NWS Grand Rapids, MI
Issued by NWS Grand Rapids, MI
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086 FXUS63 KGRR 112231 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 631 PM EDT Sun Aug 11 2024 .KEY MESSAGES... - Still looks dry into Monday night and close to normal for temps for Monday - Mostly dry through midweek, the rain chances increase && .DISCUSSION... Issued at 231 PM EDT Sun Aug 11 2024 - Still looks dry into Monday night and close to normal for temps for Monday While we maintain some cyclonic flow in the mid levels being on the backside of the departing low in southern Ontario, the flow here in MI will be confluent. This will act to limit any updrafts. An area of low level convergence over far eastern parts of the CWA is shown by a few models to develop several showers Monday afternoon that quickly move east of the CWA, but most models and ensembles keep it dry. As a result its likely that the region generally stays dry through Monday night. A decaying complex will be tracking south to southwest of MI Monday with the main impact of that being the potential for clouds in our CWA. However despite some cloud cover, with the coolest air shifting east of the CWA, much of the region is expected to make a run at 80 degrees, which is close to normal for this time of the year. - Mostly dry through midweek, the rain chances increase The first part to the middle of the week looks pretty typical of August: partly cloudy, somewhat humid, and highs in the lower 80s. After that, we`ll see some changes. As the upper trough begins to slide east, the cooler temperatures will go with it and be replaced by ridging nosing into the Great Lakes. That will bring an increase in low level dewpoints and upper level heights which will be reflected in highs in the 80s. As we progress toward the end of the week, confidence is increasing that we`ll see some troughing develop over the Great Lakes. A phasing of the northern and southern streams may bring in a couple of short waves that help to carve out the upper trough beginning Thursday. The resulting surface low will slowly move east across the state Thursday night through at least Sunday night, and perhaps have an influence on our weather through the following Tuesday. Showers and thunderstorms are in the forecast beginning Thursday and continuing through the weekend. Most members of the ECMWF ensembles point toward rain...perhaps at least a half inch...during this time. Temperatures that rise into the 80s Tuesday-Thursday will retreat to the 70s late week and over the weekend as clouds and precipitation develop. && .AVIATION /00Z TAFS THROUGH 00Z TUESDAY/... Issued at 627 PM EDT Sun Aug 11 2024 Diurnal cumulus are diminishing with most terminals going SKC overnight. The exception is GRR and MKG where nearby stratocu development supports FEW clouds in the 6kft-8kft range. Daytime Cu develop late morning tomorrow in the 4kft-7kft range with a cirrus deck providing high VFR cigs. Isolated showers cannot be ruled our near LAN/JXN after 18z Monday but given low confidence and low potential coverage will leave the TAFs dry. Winds from the west at or below 10 knots are expected through the TAF window. && .MARINE... Issued at 231 PM EDT Sun Aug 11 2024 Waves were generally in the around 3 feet and trending slowly downward. Webcams at several sites suggest the waves are a bit higher near the piers. Thus, some swim risk still exists. No further increase in the values are predicted this evening as the pressure gradient and mixing heights decrease. We will let the marine/coastal headlines expire at 5 pm today. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...None. && $$ DISCUSSION...MJS/04 AVIATION...Thomas MARINE...MJS