Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 202332
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
732 PM EDT FRI MAY 20 2016

LATEST UPDATE...
Aviation

.SYNOPSIS...
Issued at 300 PM EDT Fri May 20 2016

A high pressure ridge will continue to dominate the weather
pattern and produce fair weather along with a continued moderating
trend of temperatures through the weekend into early next week.
The next chance for showers will come late Tuesday or Tuesday night
with a better chance for showers and perhaps some
thunderstorms beginning Wednesday.

&&

.SHORT TERM...(This evening through Sunday night)
Issued at 300 PM EDT Fri May 20 2016

Short term fcst concerns remain minimal. Decided to introduce
mention of a small chc of light rain showers over our far se fcst
area late tonight and Saturday based on a consensus of short range
computer model guidance trends the past 24 hrs.

A few light rain showers and sprinkles are already noted across
northern IN. A few light showers may clip our extreme sse fcst area
in the vicinity of a sfc trof and in pva as an upper level trough
moves through.

Otherwise fair wx will continue for the vast majority of our fcst
area tonight through the weekend as the high pressure ridge remains
in control of the wx pattern. High temps this weekend will reach the
lower to middle 70`s.

12z short range guidance consensus time height rh x sections
suggest a fair amount of high cloud cover will linger through
tonight and much of Saturday with more sun for Sunday.

.LONG TERM...(Monday through Friday)
Issued at 300 PM EDT Fri May 20 2016

Narrow upper ridge across the central Great Lakes on Sunday and
Monday begins to break down on Tuesday. Showers could move in as
early as Monday night, but the chances are low enough to leave out
of the forecast for now.

Coverage of storms should increase on Wednesday as sfc based
instability is expected to be sufficient. Strong moisture return
results in sfc dew points surging into the lower to mid 60s.

Showers and a few thunderstorms  linger through Friday as sfc
boundary becomes aligned with upper flow and stalls over or just
south of Lower Michigan with at least one wave moving along it. We
will carry chance POPs  along with slight chance for thunderstorms
Thursday and Friday.

&&

.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 731 PM EDT Fri May 20 2016

VFR conditions will prevail through 00z Sunday at all TAF sites.
There is a storm system passing off to the southeast of Lower
Michigan tonight into Saturday. The rain from that system may get
a far northwest as JXN between 05z and 12z if the HRRR or RAP
models are correct. if the rain does get that far northwest JXN
would likely still be VFR so for now I did not include this in the
TAF. Elsewhere and otherwise...skies (mid and high clouds)should
clear from west to east Saturday afternoon into Saturday evening.


&&

.MARINE...
Issued at 300 PM EDT Fri May 20 2016

High pressure centered over the Great Lakes region will continue
to result in minimal wind and wave action with wave heights aob 2
ft through the weekend.


&&

.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...Laurens
SHORT TERM...Laurens
LONG TERM...Ostuno
AVIATION...WDM
HYDROLOGY...JAM
MARINE...Laurens



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