Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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410
FXUS63 KGRR 261928
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
328 PM EDT Thu Apr 26 2018

LATEST UPDATE...
Short Term/Long Term/Marine/Hydro

.SYNOPSIS...
Issued at 132 PM EDT Thu Apr 26 2018

A series of cold fronts will bring the risk of showers early
Friday morning then a better chance of showers Friday evening into
Saturday morning. The showers may mix with snow Saturday morning.
The showers should come to an end by midday Saturday. Even so it
will continue to be breezy through the day with highs struggling
to make 50 degrees. Sunday should be mostly sunny with highs in
the 50s. A significant warm is expected Monday into Wednesday with
highs reaching well into the 70s Tuesday and Wednesday. Expect
some showers and thunderstorms too by mid week.

&&

.SHORT TERM...(This evening through Saturday night)
Issued at 327 PM EDT Thu Apr 26 2018

There are two cold fronts coming through Southwest Michigan
tonight and tomorrow night. The chances of seeing significant
precipitation is greatest with the second frontal system tomorrow
night into Saturday morning.

We have a 120 knot polar jet core heading southeast from central
Canada toward western Lake Michigan by Friday morning. The exit
region lift ahead of that jet core will result in a few showers as
the first of two cold fronts come through the area.

As that jet core heads into the base of the upper trough an upper
low closes off over Lower Michigan by early Saturday morning. That
puts southwest Michigan in the deep cold air and cyclonic side of
the polar jet. That suggests showers and over northern sections it
should get cold enough to see a few wet snow flakes early Saturday
morning. Based on the way the system is coming through it would
seem the area near and south of I-96 has will more likely see the
greatest precipitation from this event.

Typical of this month so far, we have more cold air heading this
way. The coldest air will arrive behind the second cold front
Saturday morning. I could see highs only in the 40s Saturday.



.LONG TERM...(Sunday through Thursday)
Issued at 327 PM EDT Thu Apr 26 2018

What may seem like change in our weather pattern, a surge of
nearly summer warmth is expected Monday into Wednesday before yet
another cold front comes through and brings the cooler air back
once again. Of courses with warm air in place and a frontal
system thunderstorms are a good bet with the cold front mid week.

This warm up is from a closed upper low being sheared out by and
upstream wave. Just how this all plays out will depend on how the
northern and southern stream jets interact. The models have been
all over the place with that, so when it actually rains remains to
be seen. It is more than possible we could see highs in the lower
80s between Tue and Wed depending on how much sun wee see.

&&

.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 132 PM EDT Thu Apr 26 2018

Solid VFR conditions are expected through most of the next 24hrs.
There is a frontal system moving through the area mid morning
Friday and that may have some rain showers with it, since this is
not a sure thing I put VCSH for that. There is likely to be a band
of MVFR cigs near and north of I-96 (about 3 hours wide) with the
front too. I would expect most of the TAF sites will remain VFR
even so. MKG has the greatest risk of seeing MVFR cigs for a few
hours mid morning Friday.

I expect there will be a lake breeze today and when it kicks in
and moves east expect an around an hour of gusty winds so I added
that to the TAFs around 21z.


&&

.MARINE...
Issued at 327 PM EDT Thu Apr 26 2018

I have issued a Small Craft Advisory for the northern sections of
the near shore from late tonight into mid morning Friday due to 3
to 5 foot waves. Winds and waves will subside for a time behind
the front Friday morning but increase even more so behind the
next front early Saturday morning. Likely a Small Craft Advisory
will be needed then too.

&&

.HYDROLOGY...
Issued at 327 PM EDT Thu Apr 26 2018

Steady or slowly falling stages continued this morning on area
rivers and streams.  River advisories for low area flooding remain
in effect for Evart...Ionia...Eagle...and Maple Rapids. These will
continue to fall slowly over the next few days.

Precipitation is expected tonight into Friday...but forecast amounts
are low and will not impact river stages.  Multiple precipitation
events are expected during the middle and latter portions of next
week...which may cause a new round of rises on area rivers.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...Small Craft Advisory from 2 AM to 11 AM EDT Friday for LMZ848-
     849.

&&

$$

SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...WDM
AVIATION...WDM
HYDROLOGY...MWS
MARINE...WDM



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