Area Forecast Discussion
Issued by NWS Grand Rapids, MI

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS63 KGRR 180556
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
156 AM EDT Fri May 18 2018

LATEST UPDATE...
Aviation

.SYNOPSIS...
Issued at 301 PM EDT Thu May 17 2018

Dry weather will continue through Friday with highs reaching the
lower 70s in many areas. Rain chances return Friday night with
thunderstorms possible around I-94 Saturday afternoon. Chances for
showers and thunderstorms will continue for much of the weekend. Dry
conditions return Tuesday and last through most of the remaining
week. Highs will generally be in the 70s through the period.

&&

.SHORT TERM...(This evening through Saturday)
Issued at 301 PM EDT Thu May 17 2018

No substantial forecast changes. Currently seeing gusts approaching
30 mph around Alma in closest proximity to the northeast wind off
Saginaw Bay. Dry advection with the northeast winds will keep low
clouds from being an issue overnight.

Friday will see cooler high temperatures overall with the warmest
readings most likely along the Lake MI lakeshore or slightly farther
inland. High level cloudiness should begin to increase from south to
north in the afternoon and have introduced a slight chance for rain
showers along I-94 by late afternoon.

Agree with previous forecast regarding limited precipitation
amounts. Latest guidance is less wet with total accumulations only
as high as a couple tenths of an inch around I-94. This is also
where thunderstorms would be most likely to occur, especially
around Jackson, although probabilities are not high.

.LONG TERM...(Saturday night through Thursday)
Issued at 301 PM EDT Thu May 17 2018

Late Sunday into early Monday could see a healthier round of
convection associated with a strong upper PV max accompanied by low
level theta-e advection. Thunderstorms look more likely overall with
this system. Precipitation is expected to linger through Monday and
exit by Tuesday morning. Afterwards, the rest of the week generally
looks dry with a warming trend as northwest flow aloft remains in
place.

&&

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 156 AM EDT Fri May 18 2018

The majority of the fcst period will be VFR with only gusty winds
causing impacts. The end of the period will see more impacts
develop with MVFR-IFR cigs and some rain move in.

Only high clouds are affecting the region early this morning. A
dry air mass and a well mixed boundary layer is keeping fog
potential down to about zero this morning. Winds will become gusty
mid-morning, and will last through mid evening.

Mid level clouds will arrive late this afternoon ahead of the next
system. Low clouds will then move in after 00z with some chances
for rain showers developing. We may approach IFR conditions right
before the end of the fcst period. MVFR does look likely after
00z. Wind gusts will diminish around or just after 00z.

&&

.MARINE...
Issued at 301 PM EDT Thu May 17 2018

Easterly/offshore flow expected through Saturday which will limit
wave growth. Winds tonight could approach 20+ knots farther north,
but this is marginal and rather uncertain.


&&

.HYDROLOGY...
Issued at 149 PM EDT Thu May 17 2018

River levels are high across southern Lower Michigan due to the
recent heavy rains. The rivers in central Lower Michigan are near to
a little above normal. A river flood warning continues for the
Portage River near Vicksburg. All other sites have crested below
flood stage. Under three tenths of an inch of rain is expected
Friday night and Saturday with additional rain possible early next
week. This may lead to a slowdown or pause of the river level falls.

&&

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

$$

SYNOPSIS...TJT
SHORT TERM...TJT
LONG TERM...TJT
AVIATION...NJJ
HYDROLOGY...63
MARINE...TJT



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.