National Weather Service Raw Text Product

Displaying AFOS PIL: AFDGRR Received: 2020-05-22 07:13 UTC


101 
FXUS63 KGRR 220713
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
313 AM EDT Fri May 22 2020

LATEST UPDATE...
Synopsis/Discussion/Marine

.SYNOPSIS...
Issued at 313 AM EDT Fri May 22 2020

- Mostly Cloudy With a Few Showers Further Southeast Today

- Warm and Humid into the Holiday Weekend With Stormy Saturday Night

- Summery With Showers and Storms Persisting into Next Week

&&

.DISCUSSION...(Today through next Thursday)
Issued at 313 AM EDT Fri May 22 2020

-Mostly Cloudy With a Few Showers Further Southeast Today-

Most areas will see fair weather today, however skies will be mostly 
cloudy as the system that brought us record rainfall slips northeast 
through southern Ohio. We may also see a few light rain showers 
mainly within southeastern lower MI, but most areas should stay dry. 

-Warm and Humid into the Holiday Weekend With Stormy Saturday Night-

Weak and brief surface ridging will move into place Saturday 
allowing for continued fair weather. By Saturday evening, a warm 
front associated with an upper level disturbance will bring a chance 
for storms Saturday night into Sunday morning. There is a potential 
that these storms could be strong to severe as deep layer shear 
moves in, however, a good portion of the more abundant instability
still appears to stay too our south. Regardless, some organized 
convection could occur upstream in eastern IA, northern IL, and 
southern WI where there is a slightly better zone of moisture and
warm air advection. The potential exists for an elevated MCS or 
organized convection reaching us as the system moves through 
overnight. 

Beyond Saturday a warmer and more humid airmass will move in 
place thanks to deep layer southwest flow. High temperature will 
warm into the 80s with dewpoints near 70 by Monday. Guidance still
suggests fair weather Sunday and Sunday evening, then by Monday 
there is a low chance for showers as the warm and moist air mass 
interacts with an approaching trough ejecting out of Iowa. 

-Summery With Showers and Storms Persisting into Next Week-

Guidance suggests this warm and moist profile will remain in place 
well into next week with prolonged southwest flow. A frontal boundary 
will stall out over lower MI near mid-week, offering periodic 
chances for shower and thunderstorm activity thanks to weak 
shortwave impulses and possible frontal and lake breeze boundaries. 
Building high pressure to our northwest then looks to push this 
frontal boundary southeast near the end of the week. 

&&

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 141 AM EDT Fri May 22 2020

Low level moisture will be abundant today leading to impacts for
the TAF sites. IFR and possibly lower conditions look likely for
the southern TAF sites of KAZO...KBTL and KJXN. How far north
those conditions go is less certain. Outside of any IFR today will
feature abundant MVFR cloud cover. There could even be some shower
activity...especially around KJXN. An onshore wind around KMKG
could result in a bump in the ceilings there. 

&&

.MARINE...
Issued at 313 AM EDT Fri May 22 2020

Wave heights will stay low across the West Michigan lakeshore 
into the weekend as winds stay easterly. Higher water levels will 
be possible however due to recent rains, as well as prolonged 
easterly winds supporting flow from Lake Huron into Lake Michigan 
through the Straits. 

The main concerns into the weekend will be a chance for showers and 
storms Saturday night into Sunday, as well as a few diurnal storms 
into the start of next week. We may also see some possible fog along 
the lakeshore Sunday through the rest of the holiday weekend as a 
humid air mass moves over cooler lake water. 

&&

.HYDROLOGY...
Issued at 325 PM EDT Thu May 21 2020

Many of our rivers have now crested, or will be very soon, and 
begun a slow fall after the heavy rains from earlier in the week. 
The exception is on the Grand River, where the crest is currently 
located near Ada. Minor flooding is expected in Ada and Grand 
Rapids, with crests expected in the next 12 hours. Flood-prone 
locations in Comstock Park are currently experiencing major 
flooding, with roads, basements, and homes flooded. Meanwhile, as 
the crest continues down the river, a crest is expected tomorrow 
in Robinson Township, with moderate flooding of streets and some 
homes expected. Overall, this crest is expected to be the most 
significant on much of the Grand River since the flooding 
experienced in February of 2018. Here are some of the noteworthy 
crests experienced so far on the Grand River:

Ionia: 7th highest crest on record (1.20 feet less than 2018) 
Lowell: 8th highest crest on record (1.02 feet less than 2018) 
Ada: 4th highest crest on record so far (0.99 feet less than 2018)
Comstock Park (forecast): 7th highest crest (0.65 ft less than 2018)
Grand Rapids (forecast): 5th highest crest (1.17 ft less than 2018)
Robinson Twp (forecast): 6th highest crest (0.48 ft less than 2018)

The threat for rain returns to our area on Saturday night, with 
the chance for rain and storms continuing into next week. At this 
point we are not anticipating enough rain to affect the falling 
trend that will be in place by late this weekend on all of our 
rivers. 

&&

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

$$

SYNOPSIS...Thielke
DISCUSSION...Thielke
AVIATION...MJS
HYDROLOGY...AMD
MARINE...Thielke