Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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666
FXUS63 KGRR 171745
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
145 PM EDT Tue Oct 17 2017

LATEST UPDATE...
Aviation

.SYNOPSIS...
Issued at 305 AM EDT Tue Oct 17 2017

A large area of high pressure over the Central Appalachians will
remain nearly stationary over the next couple of days. This fair
weather system will lead to dry weather here in Lower Michigan.
Conditions will be breezy at times with a moderating trend to the
temperatures through Wednesday.

&&

.SHORT TERM...(Today through Thursday)
Issued at 305 AM EDT Tue Oct 17 2017

The high pressure system setting up over the Central Appalachians
will remain nearly stationary over the next couple of days. There
will be a cold front dropping down from the northwest on
Wednesday. The low pressure system associated with this front will
be rather deep with sub 980 mb pressure readings as it tracks
eastward through the Canadian Prairies through Wed. As a
result...a tight pressure gradient will set up between the low and
high pressure systems. This will support a rather long period of
gusty winds...especially during the warmest parts of the day.
Temperature values will end up well above normal for the period
given the persistent warm air advection that will be in place.

While a front will be dropping down from the northwest on
Wednesday...this feature looks dry. This is because the main
forcing and better saturation remains well to the north in Canada.
The front will also be weakening as it moves in.

.LONG TERM...(Thursday night through Monday)
Issued at 305 AM EDT Tue Oct 17 2017

Unseasonably warm and pleasant wx will continue Thursday night
through Saturday in a south to southwest flow warm air advection
pattern on the back side of the eastern CONUS ridge. High
temperatures Friday through Saturday will range from the upper 60`s
to middle 70`s which is ten to twenty degrees above normal for this
time of year.

A cold front will move in from the west and bring a chance of
showers Sunday. Unsettled wx will then continue early next week as a
significant wx pattern change occurs as an upper level trough
amplifies over our region. As such we expect showers to linger early
next week. High temperatures Monday will reach the lower to perhaps
middle 60`s. Cooler wx will follow for Tuesday and Wednesday with
high temps Tuesday only in the 50`s.

&&

.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 144 PM EDT Tue Oct 17 2017

The main weather feature in terms of aviation the next 24 hours
will be the wind. Southwest winds of 15-25 knots are expected
through about 23z, at which time it should diminish to about 5-10
knots. South winds will pick up again on Wednesday morning after
14z to 12-25 knots. Otherwise look for VFR conditions and mainly
clear skies the next 24 hours.

&&

.MARINE...
Issued at 305 AM EDT Tue Oct 17 2017

A weak cold front will press down from the northwest Wednesday
into Thursday. As this feature bumps into the high pressure system
over the Central Appalachians...the pressure gradient will tighten
up over the nearshore zones. This will support gusty winds at
times leading to hazardous marine conditions for small craft.


&&

.HYDROLOGY...
Issued at 1104 AM EDT Mon Oct 16 2017

Rivers seem to be cresting lower than expected. Most likely
relatively dry soil, low inland lake levels, and fairly low river
level base states (due to abnormally dry weather the past few
months) have mitigated many of the impacts. Some impacts still
remain in southern Van Buren and western Kalamazoo counties where
rain totals ranged between 6 and 9 inches. Roughly 10 roads were
closed due to flooding in southern Van Buren and some may have been
washed out. The Paw Paw and Black Rivers are running high, perhaps
out of banks in spots, but appear to be cresting today. Dry weather
the rest of this week will allow rivers to subside.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...Small Craft Advisory until 8 PM EDT Wednesday for LMZ844>849.

&&

$$

SYNOPSIS...MJS
SHORT TERM...MJS
LONG TERM...Laurens
AVIATION...Duke
HYDROLOGY...CAS
MARINE...MJS



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