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713
FXUS63 KGRR 301148
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
748 AM EDT FRI SEP 30 2016

LATEST UPDATE...
Aviation

.SYNOPSIS...
Issued at 315 AM EDT Fri Sep 30 2016

Low pressure will slowly spin across Lower Michigan bringing wet
weather through the weekend. Fair weather will finally arrive
early next wee as the low finally moves away.

&&

.SHORT TERM...(Today through Sunday)
Issued at 315 AM EDT Fri Sep 30 2016

No changes to the Flood Watch. Current radar loop shows steadier
rain moving into the SE forecast area with long fetch of moisture
streaming in as the upper cutoff low spins across the Ohio Valley.
It is forecast to move north back into Lower Michigan by the end
of the period then finally get kicked east as longwave trough
moves into the western CONUS.

Expect rains to continue this afternoon and into tonight and
persist into Friday before beginning to taper off as the occluded
low moves into the forecast area. Marginally steep lapse rates
this afternoon makes diurnal enhancement of thunderstorms
possible. The persistent nature of the flow regime and the
presence of tropical moisture feeding in will mean that excessive
rains are possible and the Flood Watch will remain in effect.

.LONG TERM...(Sunday night through Thursday)
Issued at 315 AM EDT Fri Sep 30 2016

A few showers may linger into Sunday evening before fair weather
returns Monday as the upper level low will finally move east of our
region as upper ridging builds in from the west.

Temperatures will be seasonable Monday before moderating to reach the
lower to perhaps middle 70`s by next Tue/Wed. The next chance for
showers will come Wednesday night and Thursday as a strong low
pressure system moves slowly northeast into the upper midwest.

&&

.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
Issued at 747 AM EDT Fri Sep 30 2016

Rain and low stratus will bring widespread IFR conditions to Lower
Michigan through tonight. East to northeast winds will gust to 20
knots at times through the afternoon.

&&

.MARINE...
Issued at 315 AM EDT Fri Sep 30 2016

Winds and waves will continue to be hazardous to small craft
into this evening. Conditions will slowly improve tonight but the
small craft advisory may be needed to continue through tonight as
the pressure gradient continues to generate wind gusts to 25
knots. Waves will be highest further away from shore because of
the offshore component of the wind.


&&

.HYDROLOGY...
Issued at 320 PM EDT Thu Sep 29 2016

Many locations between St Johns, Jackson, Kalamazoo, and Hastings
received 1 to 2.25 inches of rain since Wednesday. A number of Grand
River tributaries are rising in response, but most have a good bit
of room left to swell before reaching bankfull. The exception is
Sycamore Creek, which should reach or exceed bankfull tonight.
Greater runoff efficiency is expected in this area from any
subsequent rain events Friday into Saturday. This increases the
concern for minor areal and river flooding.

&&

.GRR Watches/Warnings/Advisories...
MI...Flood Watch through this evening for MIZ059-065>067-072>074.

LM...Small Craft Advisory until 6 PM EDT this evening for LMZ844>849.

&&

$$

SYNOPSIS...Ostuno
SHORT TERM...Ostuno
LONG TERM...Laurens
AVIATION...Ostuno
HYDROLOGY...CAS
MARINE...Ostuno