Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 281928

Area Forecast Discussion
National Weather Service Grand Rapids MI
328 PM EDT Fri Oct 28 2016

Synopsis/Short Term/Long Term/Hydro/Marine

Issued at 328 PM EDT Fri Oct 28 2016

There will be a good chance for showers and thunderstorms from
Saturday evening into Sunday morning. Otherwise, dry conditions
are expected until Wednesday when another round of showers and
thunderstorms will be possible. High temperatures will be
unseasonably warm well into the 60s just prior to each of these
rain events...but otherwise seasonal in the 50s.


.SHORT TERM...(This evening through Sunday night)
Issued at 328 PM EDT Fri Oct 28 2016

Little change to the previous forecast. Kept the mention of thunder
Saturday night based on expectations for elevated instability and
decent upper forcing as also noted in the SPC day 2 outlook.

.LONG TERM...(Monday through Friday)
Issued at 328 PM EDT Fri Oct 28 2016

A warmer than normal period is expected during the long term period
(next week). Followed the ECMWF for guidance, but the GFS is not too
much different. The ECMWF has 850mb temps in the +10C to +14C range
most of the week. We should see highs at least in the upper 50s next
week. In fact we have highs around 70 in the south on Tuesday.

Zonal flow is expected the bulk of the week with fairly high heights
for this time of year. One shortwave trough of note will swing
through the northern Great Lakes Monday night into Tuesday. Have
small chances for showers across Central Lower Monday night. Another
shortwave trough is forecast to move through the area Wednesday
night into Thursday. The best chances for rain and even a few
thunderstorms will come Wednesday into Thursday of next week as a
warm front looks to be situated across southern Lower Michigan.
Surface high pressure builds in for Friday.

Bottom line, a warmer than normal week with the best chances for
rain coming mid week.


.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 155 PM EDT Fri Oct 28 2016

Low clouds continue to shift northward early this afternoon, with
KMKG the only site along/south of I96 still hanging on the MVFR
ceilings. This should change quickly as warmer air surging in knocks
out the low clouds.

The next item of note will be the wind. Winds are picking up
currently out of the south. A continued increase in the wind will
occur even into tonight. A core of wind will peak overhead around
2am, with southwest winds around 60 knots near 3000ft off the
ground. Down at the surface southwest winds of 15-30 knots will
be common after dark. Winds will taper back off after sunrise and
through the day on Saturday.

Low clouds will infiltrate the area once again tonight into
Saturday morning. MVFR ceilings will begin pushing back in from
the north after 05z overspreading the entire area by about 12z on
Saturday. There are some indications that we may even see IFR
ceilings on Saturday, but left that out for now.


Issued at 328 PM EDT Fri Oct 28 2016

Small Craft advisory looks on track with waves commonly 5 feet or
more overnight. Gusts around 35 knots will be possible, but not
frequent enough to justify a gale warning at this point. Main
concern moving forward will be whether the noon Saturday expiration
time looks on track. This may have to be extended into early
afternoon based on latest run of the GLERL model.


Issued at 328 PM EDT Fri Oct 28 2016

Total rainfall of up to three quarters of an inch is possible
tonight and Saturday night into Sunday over Southwest Lower
Michigan. As the rivers are running above normal for this time of
year, rivers and streams, though expected to mostly stay below
bankfull, may in fact end up in minor flood state.


LM...Small Craft Advisory until noon EDT Saturday for LMZ844>849.



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