Area Forecast Discussion
Issued by NWS Grand Rapids, MI
Issued by NWS Grand Rapids, MI
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865 FXUS63 KGRR 132335 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 635 PM EST Wed Nov 13 2024 .KEY MESSAGES... - Rain Tonight and Thursday - Chance of showers on Sunday - Stronger system possible Tuesday/Wednesday && .UPDATE... Issued at 635 PM EST Wed Nov 13 2024 The forecast remains on track from the previous discussion. The onset of rain may be delayed slightly due to the dry air in place, but once we saturate rain will continue through Thursday. && .DISCUSSION... Issued at 350 PM EST Wed Nov 13 2024 - Rain Tonight and Thursday Some minor tweaks to timing of POPS moving in this evening, otherwise no changes to the previous forecast. Leading edge of rain is currently across central Ill/Ind and moving north. It will be reaching the southwest zones around 23Z. Upper level divergence courtesy of a coupled jet structure will have deep Gulf inflow to work with and storm total QPF of 0.75 to 1 inch is expected before the center of the low jumps to the East Coast. Once that happens on Thursday afternoon, the steadier rains are expected to diminish to showers and some lake-enhanced rain bands as drier air starts advecting in from the north. - Chance of showers on Sunday While there may be a lingering rain shower that lasts into Friday, we should see mostly dry conditions for Friday and Saturday. Ridging will be building over the area in the wake of the system moving through tonight and Thursday. There looks to be just a few lake effect rain showers that persist right near the lakeshore with the flow from the NNW. These will end by later Friday, and give way to dry conditions that will continue through Saturday. The amplified, yet progressive upper air pattern will keep systems moving across the CONUS. A large long wave trough coming into the western portion of the country will be the next system up for the area on Sunday. The models are suggesting that a low will cutoff over the desert SW, and the northern stream of the jet will progress across the northern tier of the country. This will move in for the Sunday time frame. If the branches of the jet indeed split, the moisture for the northern branch will be meager without a connection to the Gulf. This system will move out quickly by Monday, allowing for another dry day, with only slightly cooler temperatures in its wake. - Stronger system possible Tuesday/Wednesday The upper low that is forecast to cut-off from the long wave trough later this week, is forecast to eventually be picked up by another long wave trough moving onshore over the Western U.S., and be lifted NNE toward the region. If this occurs, this system will draw quite a bit of Gulf moisture northward with it, and bring a much better chance of widespread rain to the area. This would likely happen in the Tuesday/Wednesday time frame. && .AVIATION /00Z TAFS THROUGH 00Z FRIDAY/... Issued at 635 PM EST Wed Nov 13 2024 VFR conditions will gradually deteriorate as rain moves in from the southwest. Low level wind shear will also be present with the low level jet over the western half of the area mainly between 3-6Z. As the low pressure system advances expect ceilings to drop to IFR values from 6-12Z from west to east. MVFR visibilities are also likely looking at current visibilities upstream. Low ceilings, reduced visibilities, and rain continue through the day Thursday. && .MARINE... Issued at 350 PM EST Wed Nov 13 2024 Offshore winds through Thursday will generally remain below 25 knots with waves 2 to 4 feet. Both winds and waves will be higher out at the 5 mile mark and less near the shore. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...None. && $$ UPDATE...RAH DISCUSSION...Ostuno/NJJ AVIATION...RAH MARINE...Ostuno