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Area forecast discussion 
National Weather Service Grand Rapids Michigan
330 PM EDT Friday may 22 2015

Latest update...
synopsis/short term/long term/marine

Synopsis...
issued at 330 PM EDT Friday may 22 2015

The Holiday weekend will start out nice on Saturday with sunshine
and comfortable temperatures. However rain is expected to arrive on
Sunday...mainly across central lower. Better chances of rain move
into southern lower by Sunday night and Monday.

The wet period is expected to continue into middle week...before drying
out for the latter half of the week. Temperatures will remain
warm...mainly in the upper 70s and lower 80s.

&&

Short term...(this evening through Sunday night)
issued at 330 PM EDT Friday may 22 2015

Will issue a frost advisory for most areas along and north of I-
96...and a freeze warning for the far NE counties. Clear skies and
light winds will allow temperatures to dip into the 30s...and there may be
a few 20s far NE.

Quiet weather into Saturday evening...then the risk of showers and a
few storms arrive late Saturday and into Sunday.

High pressure remains in control. We will see temperatures rebound into
the low and middle 70s for Sat and sun as southerly flow takes over
behind the high.

Added a 20 pop to areas north of I-96 Saturday night as we will see
moisture advection into the area ahead of a warm front advancing
northward. Also seeing some elevated instability which supports
some isolated thunder.

The main thrust of moisture and lift associated with the warm front
moves into central lower Sunday...and southwest lower late Sunday
night. This is the timing used to include likely probability of precipitation. Instability
never becomes strong as there should be a fair amount of clouds
around. So not expecting severe storms during this period.



Long term...(monday through friday)
issued at 330 PM EDT Friday may 22 2015

A more summerlike pattern shaping up for next week with above normal
temperatures and increasingly humid conditions. Although the pattern
will feature southwest flow aloft with a chance of showers and thunderstorms
each day... the whole week certainly will not be a washout with
several dry periods inbetween the scattered convection.

After the warm front pushes north through the Monday... offering a
high chance of showers and storms... we stay in a warm and humid air
mass much of next week with continued daily chances of showers and
thunderstorms. Confidence is low however on the daily coverage and timing of
convection especialy since the surface front looks rather weak and ill
defined.

The GFS/European model (ecmwf) do seem to agree on a decent looking shortwave lifting
northeast into the area from the Central Plains on Wednesday.
Perhaps this feature will offer a more widespread/higher probability
of rain... if the current solution holds.

&&

Aviation...(for the 18z tafs through 18z Saturday afternoon)
issued at 152 PM EDT Friday may 22 2015

With high pressure and a very dry air mass dominating our
weather...confidence is very high that VFR weather/clear skies will
continue the next 24 hours. Northwest surface winds will occasionally
gust to 20 kts through sunset then go calm tonight. By middle morning
Saturday the winds will increase out of the south to around 10
kts.

&&

Marine...
issued at 330 PM EDT Friday may 22 2015

With high pressure in control winds and waves remain low tonight.
Southerly winds take over Saturday through Sunday night and stay
under 20 kts.

&&

Hydrology...
issued at 1226 PM EDT Friday may 22 2015

Dry weather is expected through Saturday night. Rain is expected
to move in Sunday afternoon and be most widespread Sunday night.
This will be the start of a warmer and wetter pattern that will
persist through next week. National guidance advertises uniform
rainfall totals of 0.5-1.5 inches across southwest lower Michigan
through Thursday night.

Confidence in flooding remains low at this time. Rises on area
rivers can certainly be expected next week. Thunderstorms have
the potential to produce higher rainfall amounts in a short
period of time. The risk for stronger storms and heavy rainfall
will continue to be assessed over the Holiday weekend.

&&

GRR watches/warnings/advisories...
Michigan...frost advisory from midnight tonight to 8 am EDT Saturday for
miz037-038-043>046-051-052-057>059-067.

Freeze warning from midnight tonight to 8 am EDT Saturday for
miz039-040.

Lm...none.
&&

$$

Synopsis...jk
short term...jk
long term...Meade
aviation...Meade
hydrology...ebw
marine...jk

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