Area Forecast Discussion
Issued by NWS Grand Rapids, MI
Issued by NWS Grand Rapids, MI
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385 FXUS63 KGRR 290640 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 240 AM EDT Mon Apr 29 2024 .KEY MESSAGES... - Cold Front brings rain/thunder on Monday - Multiple Chances for Showers and Storms This Week - Warm Temperatures Through The Saturday && .UPDATE... Issued at 1007 PM EDT Sun Apr 28 2024 Minimal instability remains south of the warm front tonight. Mainly showers are expected overnight but some thunder can`t be ruled out. A steadier batch of showers is indicated by the 00z HRRR to arrive in the 06z-12z time frame. This activity is currently located across eastern Missouri but will head our way overnight. Looks like a wet morning commute especially along and west of a Big Rapids to Battle Creek line. && .DISCUSSION... Issued at 352 PM EDT Sun Apr 28 2024 - Cold Front brings rain/thunder on Monday Extensive cloudiness into this afternoon has so far muted any strong updrafts, although a few showers and towering cu have managed to form in the past couple hours across the southern half of the forecast area. Cannot rule out a few strong storms into early evening with deep layer shear values of 25 to 30 knots. Breaks in the clouds and surface heating could overcome the stabilizing influence of the extensive rain showers from last night into this morning. For tonight, we will watch whatever showers/storms are able to develop but they should diminish after sunset as sfc based instability diminishes, then look for showers and storms pushing in ahead of the advancing cold front overnight into Monday morning. Expect the bulk of those showers to come through between roughly 8 AM and noon on Monday with the potential for some stronger storms across the eastern forecast area as the airmass destabilizes. Scattered showers persist along and behind the cold front into Monday evening before drying works in from the west. - Multiple Chances for Showers and Storms This Week Tuesday will be the best chance for dry weather in the long term portion of the forecast thanks to a surface ridge and upper-level ridging forecast to move overhead. Ensemble probabilities have trended downward with precipitation chances for the Tuesday night into Wednesday timeframe due to questions on low-level moisture even with a vorticity maximum swinging through. An isolated shower can`t be ruled out north of M20 but given low confidence will leave the dry NBM PoPs as is. Showers and Thunderstorms more likely Wednesday into Thursday as a surface low to our west lifts a warm frontal boundary across Lower Michigan. Thursday could be the most active day of the long term period as MUCAPE values increase near to above 1000 J/kg Thursday afternoon in both ECMWF and GFS guidance with a 30-40 knot low-level jet. A shortwave then swings through the area Thursday night into Friday driving a front through keeping rain chances going. Predictability in the longwave pattern decreases notably into next weekend. While there are signals in cluster analysis and model guidance for a trough to setup over the central United States by next weekend, there is considerable variation in both the positioning and amplitude of this feature. - Warm Temperatures Through The Saturday Highs in the 60s are expected for Tuesday as a weak thermal trough quickly passes through the region. Temperatures warm for the mid to late work week into the 70s, with the 80s not out of the question, as southwest flow brings plenty of warm air into the Central Great Lakes. && .AVIATION /06Z TAFS THROUGH 06Z TUESDAY/... Issued at 241 AM EDT Mon Apr 29 2024 TAF sites are situated with a warm front along Interstate 96 and a cold front upstream over Iowa. The I-96 TAF sites are located right near the warm front and as such have been going in and out of IFR conditions. The warm front will move a bit north and VFR conditions develop and it drops south and 400 foot ceilings develop. Model forecasts show the front pushing north this morning so the IFR potential may just be for a few hours early this morning 06Z to 10Z or so. We will see some rain spread in from the southwest towards or around 09Z to 10Z. Several hours of rain are expected at any one TAF site, ending towards 16Z. VFR Weather should dominate after that with the cold front sweeping through mainly dry this evening. Winds will become southwest at 15 to 25 knots today after the morning rain. && .MARINE... Issued at 352 PM EDT Sun Apr 28 2024 Webcams and satellite do not show any extensive areas of dense fog over Lake Michigan this afternoon as winds have apparently been able to prevent its formation. We will keep mention of patchy fog in the marine zones for this evening. Winds and waves increase Monday afternoon and a Small Craft Advisory may be needed although conditions looks marginal. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...None. && $$ UPDATE...Hoving DISCUSSION...Ostuno/Thomas AVIATION...Duke/Thomas MARINE...Ostuno