Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 210700
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
300 AM EDT SAT MAY 21 2016

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

.SYNOPSIS...
Issued at 300 AM EDT Sat May 21 2016

Dry conditions will prevail until Tuesday...then from late Tuesday
through Friday there will be a continued chance for showers and
thunderstorms. High temperatures will generally increase from the
mid 70s this weekend to near 80 by the middle of next week. The
exception will be the lake shore which will be substantially
cooler due to lake breezes developing most afternoons.

&&

.SHORT TERM...(Today through Monday)
Issued at 300 AM EDT Sat May 21 2016

No impact weather expected and no real changes to the forecast.
Looking less likely our southeast forecast area will even see
sprinkles this morning. Substantial high clouds over lower Michigan
associated with the deformation zone north of the upper low should
shift east out of the area later today as the low tracks east.

.LONG TERM...(Monday night through Friday)
Issued at 300 AM EDT Sat May 21 2016

We will see a continuation of the dry and warm period linger into
the long term starting with Monday night. The pattern will shift a
bit then starting on Tuesday as a unsettled period is expected with
temperatures remaining warm.

We will see the upper ridge hold for a little while longer through
Monday night, and then move east on Tuesday. This will continue the
warm and dry pattern that we have seen for the past few days. We
will likely have at least a portion of the CWFA hit 80 degrees on
Tuesday before the unsettled weather moves in.

The upper ridge will slide east of the area then late Tue, allowing
for a SW flow aloft to establish itself over the region. This will
open up the door for better moisture to be drawn north out of the
Gulf of Mexico as short wave troughs ride the SW flow up over the
area. Chances for showers and storms will start late Tue and hold at
least into Thu when a stronger wave is shown to pass through. We
will remain on the warm side of the jet.

The forecast becomes a bit uncertain by Fri, mainly because of the
timing of additional waves moving out of the Wrn upper low. The may
be a break between the better wave moving through Wed/Thu and the
next wave poised to move through. It could occur as early as Fri, or
hold off until Sat. We will keep a chance of showers/storms in for
Friday with the moist SW flow holding in across the area.

&&

.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 132 AM EDT Sat May 21 2016

We are expecting that VFR conditions will prevail at all terminals
through 06z Sunday. We are seeing lots of mid cloud cover over the
terminals as of 05z, ranging from around 6k ft at KJXN, to 15k ft
at the I-96 terminals. This cloud cover will hang around through
the morning, before moving out. Some cumulus development will take
place this afternoon, with cigs around 5-6k ft if any cigs at all.
Skies will then clear around sunset, and winds will become light.

&&

.MARINE...
Issued at 300 AM EDT Sat May 21 2016

Some hi-res guidance such as the HRRR suggests that pockets of 15-
20kt winds will be possible near the Sable Points this afternoon and
waves could push 3 feet in spots.  Otherwise winds will generally
remain well under 15 knots with waves mostly under 2 feet.

&&

.HYDROLOGY...
Issued at 1200 PM EDT Fri May 20 2016

The lone advisory that is out at this time is Maple Rapids. River
levels may fall low enough to cancel this by early Saturday morning,
if not by late tonight. There are no concerns at this time.

Dry air continues to dominate the overall weather pattern for now.
A shower or two may develop along the Indiana/Michigan border, but
should stay far enough south to keep our forecast area void of
rainfall. We then get into plenty more sunshine Saturday through
the daytime hours Monday. Chances for rain gradually increase late
Monday through the middle of next week. While conditions look
wetter and more active for that period, variability in the medium
range models make the extent of this moisture questionable. By
that time, rivers will have fallen and may have some room to
maneuver.

&&

.GRR Watches/Warnings/Advisories...
MI...None.
LM...None.
&&

$$

SYNOPSIS...TJT
SHORT TERM...TJT
LONG TERM...NJJ
AVIATION...NJJ
HYDROLOGY...JAM
MARINE...TJT



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