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fxus63 kgrr 281927 

Area forecast discussion
National Weather Service Grand Rapids Michigan
327 PM EDT Fri Jul 28 2017

Latest update...
synopsis/short term/long term/Hydro/marine

issued at 327 PM EDT Fri Jul 28 2017

Lower Michigan is in store for a fine stretch of Summer weather
right through this weekend and into the first portion of next week.
Temperatures will start off mild, and gradually become very warm.
Humidity levels will be on the increase. The next chance of rain
will likely wait until at least mid-week next week.


Short term...(this evening through Sunday night)
issued at 327 PM EDT Fri Jul 28 2017

Dry weather will rule for the entire short term period that GOES
through Sunday night. We will see pleasant conditions through
Saturday, then getting a bit warmer on Sunday. Humidity levels will
likely stay low through the period.

Lower Michigan will remain under control of an upper ridge that will
remain almost stationary to our northwest through the period. At the sfc,
ridging to our northwest today through Saturday will pump in much drier
Canadian air from the NE. The sfc ridge will drop south by Sunday,
bringing a more west-northwest low level flow that will advect a bit more
warmer air over the area. The dry air and subsidence will keep the
dry conditions through the weekend.

Long term...(monday through friday)
issued at 327 PM EDT Fri Jul 28 2017

For the most part this period will see near normal tempeatures and
while it will remain dry Mon and Tuesday, it now seems the risk of
significant precipitation Wednesday into Thursday is increasing.

The long wave pattern features a split upper jet with then northern
branch locked up in Canada (which will keep the truly cold air near
the arctic) and more dominant southern branch. The longwave pattern
feature a West Coast ridge and and East Coast trough. Pacific storms
dig into the off shore West Coast trough, the ride over the western
Continental U.S. Ridge finally digging into the East Coast trough. Since
southwest Michigan is on upstream part of the eastern trough it will
remain dry here through Tuesday.

However there is a really strong storm from Siberia heading across
the Pacific early next week that will Load into the trough off the
West Coast. That will deepen the West Coast trough, build the
western ridge and finally dig the East Coast trough. It is this
scenario that I believe will finally lead to measurable
precipitation in the I-94 to I-96 area in the Wed/Thu time frame.
Given the system creating this is now leaving Asia, timing is
questionable but I do believe the chances of more than a tenth of an
inch of rain in the Wed/Thu time frame is improving.


Aviation...(for the 18z tafs through 18z Saturday afternoon)
issued at 111 PM EDT Fri Jul 28 2017

Solid VFR conditions will prevail through Saturday night (actually
into monday). There will be gusty winds this afternoon from the
northeast and scattered flat cumulus clouds with cloud bases
mostly above 4000 ft agl. Winds will diminish to around 5 knots
tonight with clear skies then gusty winds and a few cumulus clouds
during Saturday late morning into mid afternoon.


issued at 327 PM EDT Fri Jul 28 2017

Winds and waves have been behaving thus far today with the offshore
flow. Winds have been just below 20 knots, with most of the buoys
reporting 2 to 3 foot waves. With these conditions, we will hold off
on any Small Craft Advisory or beach hazards headlines.

We will likely see similar conditions on Saturday, approaching
criteria, but not strong enough to exceed it. We will continue to
monitor the potential need for headlines if conditions end up a
little stronger.


issued at 327 PM EDT Fri Jul 28 2017

A handful of rivers in central lower Michigan continue to run above
normal due to recent rainfall. The remainder of sites are near
normal and trending lower. A dry weekend and very little rainfall to
add over the course of the next week will allow above normal rivers
to fall with no change expected with current rises. No flooding is


GRR watches/warnings/advisories...



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