000 FXUS63 KGRR 211708 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 1208 PM EST Fri Feb 21 2020 LATEST UPDATE... Aviation .SYNOPSIS... Issued at 330 AM EST Fri Feb 21 2020 - Dry weather is expected through Sunday - Warming trend into the weekend - Chances for rain/snow next week in complex evolution - Cool down again mid to late next week && .DISCUSSION...(Today through next Thursday) Issued at 330 AM EST Fri Feb 21 2020 -- Dry weather is expected through Sunday -- Sprawling high pressure over much of the eastern two thirds of the country will result in dry weather for the Great Lakes region. We will be dry from today through at least through Sunday, a rare 3 day stretch of dry weather in the Great Lakes for this time of year. BUFKIT profiles are about as dry as I have seen in months with very limited moisture from the surface through 25,000ft all the way out into Sunday night. Sunday night is the time frame where some low level moisture begins to show up. -- Warming trend into the weekend -- A "warming" trend, at least by February standards is expected as we head through the next few days. 850mb temperatures are near -10 C at this time, warming to -4C midday today to zero C midday Saturday and to +1C midday Sunday. This will result in highs reaching the 30s today and 40s in many areas on Saturday and Sunday. Normal highs are in the mid 30s, so in some areas by Sunday we will be approaching 15 degrees warmer than normal. Guidance high temperatures on Sunday are approaching 50F for many areas to the south and east of GRR. -- Chances for rain/snow next week in complex evolution -- The pattern early to mid next week is what I would describe as a complex evolution for sure. The initial shortwave to affect our area is currently off the Southern California coast. It moves east and induces surface cyclogenesis east of the Rockies on Sunday. The low moves our direction and eventually weakens Monday night into Tuesday as it moves into confluent upper flow. The ECMWF is favored as it has pretty consistently shown the low to move up the Ohio Valley. The GFS has been further north and is now trending south towards the ECMWF track. A second upper shortwave enters the picture on Monday from the Northern Plains with this resulting in a deepening trough over the plains and Great Lakes. As northern stream energy begins to interact with this second upper shortwave mid week a full latitude trough develops over the eastern half of the country. A rapidly deepening low moves up the Appalachians and into Quebec. In terms of what to expect in terms of sensible weather we are looking at precipitation likely holding off until into Monday. Rain will trend towards rain and snow into Monday night with snow being the dominant precipitation type into Tuesday and Wednesday. We could be looking at some accumulating snow during the Tuesday night and Wednesday time frame as the low deepens off to our east. The snow does not look all that heavy, but several inches appear possible with the current ECWMF across Southern Lower Michigan. -- Cool down again mid to late next week -- As the deep low moves into Eastern Canada, colder air is pulled south into the Great Lakes region. -15C air is in place midday Thursday. Highs next Thursday and Friday will likely be back into the 20s F. && .AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon) Issued at 1207 PM EST Fri Feb 21 2020 VFR will continue through Saturday. Southwest winds will gust over 20 knots at times through this evening. && .MARINE... Issued at 330 AM EST Fri Feb 21 2020 A strong pressure gradient sets up across the Great Lakes today between a 1035mb high in the Ohio Valley and a 980`s mb low over Hudson Bay. 40-45 knot gales are likely on Lake Michigan, especially the north half of the lake. In our area, 35-40 knot gales look likely. Waves will build steadily through the course of the day, reaching 6 to 9 feet at sunset across the entire nearshore area. The highest waves will be found to the north towards Big and Little Sable Points. Waves will peak near midnight around 10 feet. We have a Gale Warning and a now a Lakeshore Flood Advisory from 100pm this afternoon through 100am tonight. Water level models show the lakeshore flood aspect being a bit less of a concern but we are still expecting beach/dune erosion. Some webcams and photos from the lakeshore recently have shown quite a bit of ice, but this is not consistent up and down the length of the lakeshore. Therefore, there is not a buffer from the water/waves in many areas. Case in point, the shortwave IR which shows ice fairly clearly on a clear winter night (like the Straits and Saginaw Bay) shows no ice in our nearshore which means what is there is very narrow or none at all. We will need a Small Craft Advisory on the back end of the Gale once we drop that headline tonight. The SCA will be needed overnight and through Saturday as it will take all day Saturday for the waves to fall below 4 feet. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...Lakeshore Flood Advisory until 1 AM EST Saturday for MIZ037-043- 050-056-064. LM...Gale Warning until 1 AM EST Saturday for LMZ844>849. && $$ SYNOPSIS...Duke DISCUSSION...Duke AVIATION...Ostuno MARINE...Duke

NWS GRR Office Area Forecast Discussion