Area forecast discussion National Weather Service Grand Rapids Michigan 121 PM EDT Thursday may 23 2013 Latest update... aviation Synopsis... issued at 327 am EDT Thursday may 23 2013 Showers will linger through the morning hours...but then as drier air moves in from the northwest the rains will come to an end through the afternoon and early evening from northwest to southeast. After a gloomy start to the day most areas will see some sunshine by late afternoon or early evening. This clearing will be the start of quiet period of weather which should last throughout the Holiday weekend. It will be much cooler today with highs only 55 to 60. Patchy frost will be seen tonight north of I-96. However temperatures will gradually rebound into the 60s for Friday and Saturday...and mainly into the 70s for Sunday through Wednesday. The next chance of rain should hold off until Tuesday and Tuesday night. && Update... issued at 1212 PM EDT Thursday may 23 2013 Cold front is situated across the far southeast portion of lower Michigan stretching from near the Detroit metropolitan area southwest into portions of Northeast Indiana. Clouds are in place across the entire forecast area with rain showers lingering Post frontal across the bulk of the forecast area yet. Heavier showers at this point continue from the Interstate 96 corridor south...with lighter showers and drizzle to the north. Expect a gradual end of the showers from north to south over the course of the next 6 to 8 hours...with the bulk of the rain over by 800pm or so. Clouds will begin to clear as well in the same fashion...with skies turning partly cloudy in the northwest toward Ludington this afternoon. Clouds will begin clearing out during the evening from Holland to Alma and in the southern County Warning Area towards sunset. High temperatures will be tempered by the clouds and rain with most sites seeing afternoon highs in the upper 40s to middle 50s. && Short term...(today through saturday) issued at 327 am EDT Thursday may 23 2013 A cold front cut across the County Warning Area this morning and it will continue to sag to the south today. Fgen behind the front was supporting a band of showers over eastern WI/Lake Michigan early this. This rain will swing through the County Warning Area from northwest to southeast through the course of the day. Upper dynamics were also helping this area of rain...and the right entrance region of the jet will slide over the County Warning Area with the rain. So needless to say the band of rain should hold together and it looks wet through the morning. Then the back edge of the rain will gradually sag southeast through the County Warning Area through the afternoon and early evening. Much drier air moves in and skies will clear late today. This should give most areas a late afternoon/early evening high temperature as a bit of sunshine boosts the temperatures up a bit. Will go ahead with a frost advisory across the northern County Warning Area tonight. This does not look like a prolong event with the nights being so short this time of year. Also with the winds likely staying up through the evening the actually time frost will develop should only be 3 to 5 hours. Localized areas may fall to below freezing in the normally cold low spots...but this should be too brief and too isolated to need to consider a freeze warning. High pressure and quiet weather prevails for Friday and Saturday. Frost potential appear to be lower for Friday night given that some middle/hi clouds should be moving in on the heels of warm advection aloft. Will mention patchy frost for now and will need to monitor cloud trends. Daytime temperatures warming slightly each day. Long term...(saturday night through wednesday) issued at 327 am EDT Thursday may 23 2013 A classic Hudson Bay high will visit our area into Monday providing little in the way of cloud cover and slightly below normal temperatures through Memorial Day. This will block any attempts of southern stream shortwaves from bringing any clouds and precipitation into the area. Beyond Memorial Day the forecast gets more uncertain. While we start out with an Omega block type pattern (which is why it should stay mostly clear into Memorial day) over time a powerful storm currently near Japan crosses the North Pacific gaining support from a system in the Bering Sea late in this weekend. The system reaches the West Coast in the Wednesday time frame. Now there already a system stalled along the West Coast. When the Japan system gets west of the dateline... that will force the current system inland and that will try to flatten the large ridge (1-2 Standard deviations from normal on the 500 mb heights) by midweek. That then sets US up to be in the line of fire for shortwaves traveling east on the southern stream jet. So just how this plays out is anyone guess... since the primary player in all of this has to cross the Pacific Ocean yet. So... all that being so I have to admit there will be a chance of showers and thunderstorms from Tuesday afternoon on. Thus in increased the pop to around 30 percent from then on through the rest of the forecast. What this means is the front stalls near US. Another aspect to this is it should get warm to hot as the upper ridge is pushed east a touch middle to late week. I could see highs well up into the 80s from Wednesday on. Again... timing shortwaves and such will be an issue with the temperatures... but bottom line Summer like weather returns by Wednesday continues well beyond Wednesday. && Aviation...(for the 18z tafs through 18z Friday afternoon) issued at 116 PM EDT Thursday may 23 2013 Moisture wrapping around the departing low pressure system will lead to a few hours if IFR weather from clouds...fog and rain to start the 18z tafs south and east of kgrr. Satellite imagery shows rapid clearing pushing southeastward toward kfks and kldm. This will be the trend for the taf sites in southwest Michigan later this afternoon. VFR weather to prevail tonight and Friday. Mixing will cause some gusty winds through 01z...but values should stay under 25 knots. && Marine... issued at 1212 PM EDT Thursday may 23 2013 Upgraded the Small Craft Advisory to a Gale Warning as gales have been occurring at the northern marine ob sites. Feel this will push south this afternoon and affect all marine zones with time. The observation at Muskegon and Holland may not show gales on land...but believe gales will likely be achieved at the edge of the nearshore zone out at 5 miles. Waves have already hit 11 feet at the southern Middle Lake buoy. && Fire weather... issued at 327 am EDT Thursday may 23 2013 More rain today will keep fire danger low. Much drier air arrives for Friday and Saturday with daytime relative humidity values lowering to around 35 percent. However winds will remain under 10 miles per hour for much of Friday and Saturday. && Hydrology... issued at 327 am EDT Thursday may 23 2013 Additional rain today will be persistent...but will be on the light side. Generally less than a quarter of inch is expected. River levels are high with one advisory valid for the Muskegon river near Croton. River levels should begin to slowly fall late today as the beginning of a dry spell moves in. && GRR watches/warnings/advisories... Michigan...frost advisory from 1 am to 7 am EDT Friday for miz037>040- 044>046. Lm...Gale Warning until 11 PM EDT this evening for lmz844>849. && $$ Update...Duke synopsis...jk short term...jk long term...wdm aviation...mjs fire weather...jk hydrology...jk marine...Duke