National Weather Service Raw Text Product

Displaying AFOS PIL: AFDGRR Received: 2018-05-16 07:30 UTC

FXUS63 KGRR 160730

Area Forecast Discussion
National Weather Service Grand Rapids MI
330 AM EDT Wed May 16 2018

Synopsis/Short Term/Long Term/Marine

Issued at 330 AM EDT Wed May 16 2018

Dry weather is forecast through the end of the work week with high 
pressure in place across the Great Lakes region through that time. 
Skies will vary between mostly clear and partly cloudy through 
Friday. Highs will push into the 70s Wednesday, Thursday and Friday. 
A few spots may even reach the 80 degree mark. The weekend will 
feature some chances for rain as a couple of systems may track near 
our area.


.SHORT TERM...(Today through Friday)
Issued at 330 AM EDT Wed May 16 2018

Limited weather concerns in the short term with a dry forecast. Some 
cirrus is in place across Southern Lower Michigan at this time and 
it appears that may continue into this evening. Also in play today 
will be the chance for some cumulus to fill in, especially across 
the southern half of the forecast area. Mainly clear conditions are 
expected from tonight through Thursday night. The upper low to our 
south may throw some high clouds into the mix for Friday to take sky 
conditions to partly cloudy there. 850mb temps do not change much 
the next 3 days so high temperatures should be similar. The caveat 
though is on Thursday and Friday when we may see an increasing flow 
off of a cold Lake Huron.

.LONG TERM...(Friday night through Tuesday)
Issued at 330 AM EDT Wed May 16 2018

The main items of interest in the long term are the upper low to our 
south on Saturday, and the system that moves through on Sunday from 
the west. 

The chances for a few showers on Saturday are increasing a little 
bit. Latest model consensus indicates that the upper low to our 
south will lift up enough to bring a good deal of cloud cover, and 
maybe a few spotty showers. Better moisture and lift will stay well 
SE of the area. Still a decent amount of uncertainty as is typical 
regarding the movement of upper lows as they tend to wobble.

We are still thinking that there is a decent chance of rain later 
Sat night and on Sun. We will see a wave emerge from the Rockies 
over the Plains, and then eventually traverse the area just south of 
the state border. The system has some Gulf moisture to work with, 
however it is not the best moisture flow as the flow is a bit 
divergent out of the Gulf. Models indicate some elevated instability 
will be present, so we will go with a mention of thunder.

Once the Sun system departs the area, we should be dry with 
moderating temperatures into Tue. 


.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 156 AM EDT Wed May 16 2018

We are looking at a forecast period with little to impacts to
aviation operations. Clouds around 3-5k ft from earlier have just
about totally dissipated as of 0530z, with only high clouds
remaining. Other than patchy fog near standing water, we expect
that conditions will remain VFR through the morning. A cumulus
field will likely form this afternoon based around 4k ft at inland
locations. KMKG will likely remain mostly clear with a lake breeze
kicking in and bringing more stable air inland. Cumulus will
dissipate around sunset, and winds will go light and variable.


Issued at 330 AM EDT Wed May 16 2018

A very quiet period is expected out on Lake Michigan through 
Thursday morning. Winds will be light, under 10 knots, through that 
time with waves that will be 1 foot or less. Thursday afternoon 
through Friday, winds will pick up from the east as the pressure 
gradient tightens between a high over Canada and low pressure in the 
Ohio Valley. The east winds of 10 to 15 knots will not kick up waves 
much in the nearshore zone given its an off shore flow. Bottom line, 
limited wave action through the end of the week.


Issued at 146 PM EDT Tue May 15 2018

One to two inches of rain fell across the Kalamazoo River basin in 
the last 24 hours...with lesser amounts in the Grand and Muskegon 
basins.  This has increased the forecast crest for rivers in that 
system and/or pushed the time of crest out further in time.  

River flood warnings continue for the Sycamore at Holt, Grand at 
Jackson, and Portage at Vicksburg.  Some of the other sites that are 
seeing strong rises could flirt with flood stage...but forecast 
trend is for them to crest lower with each issuance so will not 
issue any other warnings at this point.

Scattered showers and thunderstorms this afternoon should not have 
the areal coverage or intensity to produce rainfall/runoff that will 
impact area rivers.  Dry weather for the rest of the work week will 
allow runoff to complete and the flood crests to move downstream 
without further enhancement.