Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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375
FXUS63 KGRR 261922
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
322 PM EDT Mon Jun 26 2017

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

.SYNOPSIS...
Issued at 322 PM EDT Mon Jun 26 2017

Another afternoon and evening of spotty showers and isolated storms
can be expected tonight as cool Canadian air continues to filter
across the area. Conditions will dry out overnight as the system
begins to pull out. A stray shower will be possible across eastern
areas Tuesday afternoon, but temperatures will warm a few degrees
compared to today.

An occasionally active weather pattern is looking more likely
beginning late Wednesday, and lasting at times through early next
week. Multiple waves of low pressure will move east through the
region at times. These waves will bring the threat of showers and
storms with dry periods in between.

&&

.SHORT TERM...(This evening through Wednesday night)
Issued at 322 PM EDT Mon Jun 26 2017

One more round of spotty showers is now beginning to rotate into the
CWFA this afternoon from the NW as one more major wave moves through
the region. The shower chances will linger into the early overnight
period before the wave rotates out. A rumble of thunder will remain
possible as the cold pool aloft interacts with the diurnal heating
this afternoon.

Tuesday should end up mainly dry across the area, however a slight
chance of a rain shower was inserted into the forecast for the
eastern counties. The models have trended toward the cyclonic flow
aloft lingering a little longer. The eastern counties will be on the
wrn periphery of the upper low Tuesday afternoon. Temperatures will
be a few degrees warmer than yesterday with the core of the coolest
air moving east of the area.

We will see a break in the weather then from Tuesday evening through
Wednesday morning. Rain chances will then increase Wednesday
afternoon and especially Wednesday evening. There is a short wave
that is currently coming onshore off of the Pacific to the CA/OR
coast. This short wave will move along the nearly zonal flow that
will take place once the current low moves out. A 60 knot low level
jet is expected to bring a very moist surge to the area. This will
help develop showers/storms over the area Wed afternoon/evening.
Right now, the heavier pcpn looks to occur across the northern
portion of the area given the forecast track of the wave.

Heavy rain is a concern given the heavy rain that has fallen across
portions of Central Michigan over the last week. There is a lot of
wind energy available also that could produce damaging winds. We
will continue to monitor the situation.

.LONG TERM...(Thursday through Monday)
Issued at 322 PM EDT Mon Jun 26 2017

A Low pressure system is expected to pass over Upper Michigan/Lake
Superior Thursday and drape a front across the region, bringing
showers and thunderstorms to Lower Michigan Thursday into Friday.
Instability, moisture, and lift may all be present in sufficient
quantities to make severe weather possible.

Another low pressure system will then move from southwest to
northeast across Lower Michigan Friday and Friday night, accompanied
by more rain and thunderstorms. If the focus of the heavy rain ends
up stretching across the area, we could see areal and river flooding
by the end of the week.

Temperatures will be around normal through the week. Normal highs
are around 80 degrees and normal lows are in the upper 50s.

&&

.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 129 PM EDT Mon Jun 26 2017

Isolated showers will become more numerous this afternoon, with
thunder also possible in the afternoon and evening. Some small
hail could occur. Even with this, conditions will be mostly at or
above VFR minimum levels through Tuesday afternoon.

West winds will be gusty today at 15 to 30 kts, stronger gusts
will be possible with stronger cells. Winds will decrease below
10 knots tonight.


&&

.MARINE...
Issued at 322 PM EDT Mon Jun 26 2017

The Small Craft Advisory and Beach Hazards Statement look good and
will be maintained. We will see one more uptick in the winds and
waves this afternoon as one more wave moves by and cooler air surges
in. Conditions will start to improve tonight and settle down more on
Tuesday.

We are looking at hazardous conditions likely returning to the
waters late Tuesday night and Wednesday as the next system
approaches the area. These will likely last at least through
Thursday.

&&

.HYDROLOGY...
Issued at 1119 AM EDT Mon Jun 26 2017

River levels are trying to return to normal across the region...with
the Chippewa River at Mt. Pleasant and Pine River at Alma above flood
stage. Scattered showers and thunderstorms...which will develop as
an upper low moves over the state this afternoon...are not expected
to produce the areal coverage or intensity of precipitation needed
to slow the falling of the stages. Therefore...expect river levels
to continue to fall steadily over the next 24 hours.

Another round of potentially heavy rainfall will occur later
Wednesday into Wednesday night. Deep moisture returns to the
region...and bands of heavy rainfall may occur across central
portions of Lower Michigan. Rivers in Isabella and Gratiot
counties are especially vulnerable to excessive rainfall...and
significant rises would likely develop on the Pine and Chippewa
rivers should the heavy rainfall occur in these basins.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Beach Hazards Statement until midnight EDT tonight for MIZ037-
     043-050-056-064-071.

LM...Small Craft Advisory until midnight EDT tonight for LMZ844>849.

&&

$$

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



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