Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 241150

Area Forecast Discussion
National Weather Service Grand Rapids MI
750 AM EDT TUE MAY 24 2016


Issued at 330 AM EDT Tue May 24 2016

High pressure will slip away from the region today but should
provide one more dry day. A persistent southerly flow of air will
bring very warm and humid conditions for the mid to late week period
along with a daily risk of showers and thunderstorms.


.SHORT TERM...(Today through Thursday)
Issued at 330 AM EDT Tue May 24 2016

The sfc front remains to our west today and will be the primary
focus for convection. Will have a dry fcst with the exception of low
chance pops north of mkg late in the day as the front gets a bit
closer. Otherwise the stable southwest flow off lake michigan,
lack of any focus for convection, and capes of only a few hundred
joules support a dry fcst.

Even tonight as the front comes into the area the coverage of rain
should be minimal as diurnal component is lost, and will carry only
low chance pops. Actually the sfc front weakens overhead and becomes
rather ill-defined, then begins to rebound north as a warm front on
Wednesday. Better instability is progged on Wednesday with sfc based
capes near 2000 J/KG. However it`s unclear if the warm front will
still be in our area or will have lifted into nrn lower mi. Diurnal
convection should tend to favor the sfc convergence along this

The best chance of showers and storms in the short term period is on
Wednesday night as a shortwave and 40 kt low level jet impact
the area. Will carry likely pops during this time. After this
activity moves out of the area Thursday morning, some scattered
diurnal convection could re-fire east of the lake breeze front in the

.LONG TERM...(Thursday night through Monday)
Issued at 330 AM EDT Tue May 24 2016

Little change to the extended portion of the forecast.  The area
will remain warmer than normal, but periodic rains will be possible.

Upper ridging will still prevail over the eastern U.S. through the
weekend and into next week. This will continue to pump a warm and
moist air mass into the Great Lakes. This will keep daytime temps in
the upper 70s to mid 80s each day.  There should also be a period
from Thursday Night into Saturday where we should be rather humid,
with dew points expected to be in the 60s.

Showers and thunderstorms will be a possibility however through the
period.  The best chance of pcpn seems to be Friday and Saturday
when a northward moving low level jet sets up over the western Great
Lakes.  This will put Lower Michigan in an area of low level
convergence that will work with instability across the area.


.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
Issued at 750 AM EDT Tue May 24 2016

VFR will continue to prevail today and tonight with very dry air
still in place. the risk for a shower or storm tonight related to
incoming decaying front is too low to have in the tafs. It is
possible that some fog could develop after 09z Wednesday due to
progged higher dew points but confidence is rather low at this
time. Best chance of that would be at mkg.


Issued at 330 AM EDT Tue May 24 2016

Arrival of higher dew points over the cool lake michigan waters may
lead to areas of dense marine fog as we go through the week. Winds
and waves are expected to remain below advisory criteria in the
short term.


Issued at 607 AM EDT Tue May 24 2016

Given a summertime convective mode setting up across the region,
localized heavy rain is a possibility at times. While it certainly
won`t rain each day in every location, basin average rainfall may
end up being around an inch through the weekend, but locally more
than that could fall given mainly unidirectional flow...relatively
modest mean flow...and weaker low and mid level winds through the
period. Beginning Wednesday night...precipitable water values of
1.25-1.75 are expected and this will last through the holiday
weekend. Dew points in the 60s will advect in and could approach
70 on Friday. Flooding of main stem rivers does not seem likely at
this point given the synoptic setup, but quick rises of smaller
streams and rivers is a possibility.


.GRR Watches/Warnings/Advisories...


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