National Weather Service Raw Text Product

Displaying AFOS PIL: AFDGRR Received: 2019-01-11 00:01 UTC


872 
FXUS63 KGRR 110001
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
701 PM EST Thu Jan 10 2019

LATEST UPDATE...
Aviation

.SYNOPSIS...
Issued at 310 PM EST Thu Jan 10 2019

- Snow mostly misses us to the south Saturday.

- Potential for lake effect snow middle of next week.

&&

.DISCUSSION...(This evening through next Thursday)
Issued at 310 PM EST Thu Jan 10 2019

Forecast concerns deal with one system Saturday that will most 
likely miss the majority of the cwa. 

High pressure over Ontario is feeding colder air across the lake 
which is resulting in lake effect clouds covering the cwa. 
Instability is largely insufficient for snow at this point so we're 
left with clouds. 

A southern stream system is poised to develop over the southern 
Rockies by Friday morning and then move ENE across the TN Valley. 
The ECMWF and GFS are in good agreement that the system is going to 
form and basically where it's going to go. The difference is how far 
north the precipitation shield goes. The ECMWF is a tad farther 
north and pushes snow into far southern Lower, while the GFS keeps 
the snow south of I-80. The most impressive isentropic lift doesn't 
get much farther north than I-70 across central IN/OH. Little if any 
pressure advection was noted in the models across Michigan. We've 
stratified pops from near 0 in Montcalm county to low 60s south of I-
94. Snow potential in the southern row of counties Saturday looks 
like less than an inch. 

Mostly dry weather prior to and beyond Saturday. Highs during the 
period should range from the upper 20s to mid 30s. 

&&

.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 700 PM EST Thu Jan 10 2019

Ceilings will remain around 2500 feet AGL this evening then
gradually rise above 3000 feet overnight. VFR conditions are 
expected on Friday. Winds will be northwest less than 10 knots 
this evening then become southeast around 5 to 10 knots on Friday.

&&

.MARINE...
Issued at 310 PM EST Thu Jan 10 2019

The Small Craft Advisory will expire at 7 pm and we anticipate no 
changes to the headline. Wind and waves will slowly diminish this 
afternoon and through the evening. 


&&

.HYDROLOGY...
Issued at 330 PM EST Wed Jan 9 2019

Water levels are generally above normal for this time of year, but 
this will be changing this week with the return to winter 
temperatures. Precipitation will be in the form of snow, thus a 
trend toward dropping water levels is expected to take hold by the 
week's end across most of the rivers in West Michigan. Water 
temperatures are generally in the mid to upper 30s, except on the 
Muskegon River where lower 30s can be found. These values will 
fall through the weekend, and ice formation may be possible on 
rivers by next week. 

The Maple River at Maple Rapids continues to hover near bankfull, 
and is expected to remain around this level before a dropping trend 
starts by this weekend. No flooding is expected.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...None.
&&

$$

SYNOPSIS...04
DISCUSSION...04
AVIATION...Ostuno
HYDROLOGY...63
MARINE...04