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 270303
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
1103 PM EDT Mon Jun 26 2017

LATEST UPDATE...
Update/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.

&&

.UPDATE...
Issued at 1103 PM EDT Mon Jun 26 2017

I adjusted the probability of precipitation for the evening to
show the showers will be mostly north of Big Rapids. The showers
will weaken as they move east of Big Rapids.

&&

.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 00Z TAFS through 00Z Tuesday evening)
Issued at 727 PM EDT Mon Jun 26 2017

Expect VFR conditions through Tuesday and for that matter most of
Wednesday at all of our TAF sites.

We have a band of scattered showers moving away from our eastern
TAF sites (LAN and JXN) as I write this. However this is one more
band of showers (23z) from PLN to TVC to GRB that will rotate
through our TAF sites in the 03z to 09z time frame. Since the sun
will have set by then I would think most of these showers will
have dissipated, even so here is enough dynamic forcing with the
upper level system that it is possible they would hold together.
Even so the VSBY and CIG will remain VFR. Once they move through
the sky should clear totally. Tomorrow is the last day under this
weather system so we will have one more day of afternoon CU/TCU
and isolated rain showers. This will be more of an issue for the
eastern TAF sited due to the west wind. I put VCSH in the forecast
for those sites for Tuesday afternoon. It should not be as windy
during the day tomorrow as the system will be moving out by then.

So periods of VFR cigs tonight into Tuesday with lighter winds
Tuesday.


&&

.MARINE...
Issued at 1103 PM EDT Mon Jun 26 2017

I expunged the probability for waterspouts due to ending showers.
The marine headlines have been extended into the morning hours
due to persisting higher winds and waves in the southern near
shore zones.

&&

.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 5 AM EDT Tuesday for MIZ037-043-
     050-056-064-071.

LM...Small Craft Advisory until 5 AM EDT Tuesday for LMZ844>849.

&&

$$

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



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