Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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000 FXUS63 KGRR 221909 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 309 PM EDT Sun Apr 22 2018 LATEST UPDATE... Synopsis/Short Term/Long Term/Marine/FireWeather/Hydro .SYNOPSIS...
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Issued at 309 PM EDT Sun Apr 22 2018 The warmest day of the week will likely be Monday, with temperatures climbing to near 70 degrees for the first time in 6 months (except in areas near I-94, which already reached the 70s on April 12). Temperatures near to below normal then return for the rest of the week. Rain showers are most probable on Tuesday and Friday, but amounts will not be particularly heavy.
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&& .SHORT TERM...
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(This evening through Tuesday night) Issued at 309 PM EDT Sun Apr 22 2018 Clear skies, dry air, and light east winds will allow temperatures to fall into the 30s overnight. We will be situated under an eroding ridge on Monday, separating the cutoff low over Dixie and an approaching shortwave trough digging through south-central Canada. Mid/upper level winds will become southerly on Monday, advecting moisture and developing patches of alto/cirrostratus by late in the day. If those clouds remain thin enough for most of the day, many locations do have a good chance of reaching 70 degrees. 850 mb temperatures Monday will be 3-4 C warmer than today, so boundary layer mixing up to that level will make at least upper 60s a good bet as the ground becomes increasingly dry. East to southeast surface winds 5-10 mph will keep the lake breeze front close to the shore especially south of Muskegon, so even those communities will likely climb into the mid-upper 60s. The NAM and GFS advertise scattered showers developing in southern Michigan Monday evening from 850-800 mb moisture, but the potential is low. As the low to our south becomes reintroduced into the upper-level westerlies and starts lifting northeast into the Ohio valley on Tuesday, a cloudy day is expected with a chance of light rain. Temperatures Tuesday morning will start off fairly mild in the 40s, but highs will struggle to reach 60. Winds from the north increase Tuesday night with a cold front passing through, dropping temperatures below normal. .LONG TERM...(Wednesday through Sunday) Issued at 309 PM EDT Sun Apr 22 2018 To start the period there are some differences in the models with regard to the handling of the mid level low east of the region...but even the westernmost solution keeps the nearly all the showers east of the CWA. Will forecast a dry day for Wednesday...but will need to monitor trends on this storms position in the coming days. The next storm system will be a mid level wave that digs down from the northwest Thursday into Friday. The GFS is faster than the High Res Euro with the precipitation with this system...but even that solution supports a dry forecast for Thursday...which is what I will forecast. The moisture deepens up and lift increases with the wave moving in Thursday night. Forecast soundings from the GFS could support a rain/snow risk for far northern zones. Will feature that in the forecast...but confidence is rather low. If the High Res Euro verifies...there would be no snow up north. We will have to monitor the temperature forecast for Friday. MOS guidance from the models has values in the 50s...while GFS forecast sounding would support 40s. For now will hold values generally in the 50 to 55 degree range which are well below normal for this time of the year. Mid level heights are shown to rise going through the weekend. This will support a gradual warmup.
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&& .AVIATION...(For the 18Z TAFS through 18Z Monday afternoon) Issued at 106 PM EDT Sun Apr 22 2018 The main issue with the TAFs will be the variable wind conditions this afternoon. We have already seen the surface winds...which have been gusty at times...varying between northeast and southeast for inland sites. That will likely continue for the afternoon. Then along the lakeshore...a lake breeze was developing near KMKG. This will have to battle the prevailing easterly winds to make it further inland. It appears that the winds around KMKG will remain rather light this afternoon and continue to be variable. && .MARINE...
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Issued at 309 PM EDT Sun Apr 22 2018 Light winds from the east or north through Tuesday will keep waves low. North winds strengthen Tuesday night into Wednesday, creating hazardous conditions for small craft.
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&& .FIRE WEATHER...
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Issued at 309 PM EDT Sun Apr 22 2018 Sunday afternoon relative humidity 15-25 percent, dry vegetation, and winds gusting 15-20 mph in some locations have resulted in elevated fire danger. Winds will decrease and RH will increase after sunset. Elevated fire wx conditions are again expected Monday, with RH falling to 25-40 percent.
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&& .HYDROLOGY...
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Issued at 309 PM EDT Sun Apr 22 2018 Lowland nuisance flooding near some riverbanks will be ongoing over the next few days as water from last weekend`s mixed precipitation event moves through the river basins. Since no heavy rain events are anticipated in the next week, rivers will gradually subside.
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&& .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. LM...None. && $$ SYNOPSIS...CAS SHORT TERM...CAS LONG TERM...MJS AVIATION...MJS FIRE WEATHER...CAS HYDROLOGY...CAS MARINE...CAS

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