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Displaying AFOS PIL: AFDGRR Received: 2019-03-15 19:18 UTC

FXUS63 KGRR 151918

Area Forecast Discussion
National Weather Service Grand Rapids MI
318 PM EDT Fri Mar 15 2019


Issued at 318 PM EDT Fri Mar 15 2019

- Light snow accumulations possible west of U.S.-131 tonight with 
  any wet roads becoming slick overnight

- Small chances for rain and snow showers at times through Wednesday

- Cooler than average temperatures through early next week, then 
  warming to average and slightly above average  


.DISCUSSION...(This evening through next Friday)
Issued at 318 PM EDT Fri Mar 15 2019

We will see cool and unsettled weather settle in through the first 
portion of next week. Some rain and snow showers will be possible at 
times, however we are expecting little to no impacts at this time. 
The weather should settle down for the second half of next week, 
with moderating temperatures expected.

Probably the best chance of accumulating snow in the next seven days 
will come this evening for the western half of the area. Rain is 
trying to change over to snow with the melting layer slowly dropping 
this afternoon. Temps right at the sfc are staying just warm enough 
with the solar insolation and limited cold air advection to prevent 
a complete change over for now. This will change this evening once 
the sun goes down and the sfc can cool down a little more. The snow 
showers this evening could produce up to an inch on grassy areas 
before the upper trough passes east, and snow showers diminish in 

We remain in cyclonic flow aloft through Monday. Short waves will 
rotate through the region, but look to actually go south of the 
area, especially on Sunday. 850 mb temperatures will remain cold 
enough for lake effect being around -13C or so. What will keep the 
area from getting much lake effect will be drier low level air, and 
sfc temps over the land areas warming enough that modifies the air. 
It actually looks like we may have more diurnal cloud cover due to 
diurnal instability with the cyclonic flow overhead. We will see the 
cyclonic flow aloft push east Monday evening. 

A short wave does dive south into the mid-Mississippi Valley on 
Tuesday. This looks to stay far enough away to limit any impacts on 
Lower Michigan. A trough does go through the area on Wednesday, but 
will have limited moisture available. So we will have just small 
chances for rain or snow showers depending on the amount of diurnal 
warmth at the particular time of the day.

The weather should quiet down beyond Wednesday, with moderating 
temperatures expected. Once the wave moves out on Wednesday, the 
long wave ridge will build toward the area through next Friday, and 
beyond. Temperatures should warm to the above average category by 
next Friday. 


.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 139 PM EDT Fri Mar 15 2019

Light rain is in the process of changing over to light snow from
west to east this afternoon. We are seeing IFR cigs for the
western terminals, while MVFR cigs are present across the east.
Some spotty IFR vsbys are also present with drizzle and also where
pcpn has changed over to snow up north. We expect a general
improvement with cigs and vsbys over the next few hours,
before vsbys drop again for a few hours later this afternoon and 
this evening as snow showers intensify as the wave moves through.

Once the wave moves through, we expect a lasting improving trend
to VFR overnight and through Sat. Some light snow showers will be
possible, but should produce little to no impacts. Some locations
inland may even clear out tonight, like at KLAN and KJXN. Wind
gusts will come down overnight.  


Issued at 318 PM EDT Fri Mar 15 2019

There is still minor area flooding in central and west-central 
Michigan where some snowpack remains, and deeper snowbanks may be 
plugging up drainage routes, but the flooding is not as much of an 
urgent concern as it was Thursday night.

Generally minor river flooding is expected on a number of Grand and 
Muskegon basin forecast points. Newaygo and Bridgeton may reach 
moderate flood stage on Saturday but are forecast to stay below the 
crest of Feb 2018. Other rivers have their own varied histories, but 
generally the crests on most rivers will not exceed other crests 
seen in the last 1 or 2 years. Nonetheless, some road closures and 
basement flooding of vulnerable houses are possible.

Relatively dry pattern setting up for the next week, and 
temperatures which will not rapidly melt off the snowpack nor create 
new river ice. This will allow a more orderly discharge of high 
river flows.