Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 240713
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
313 AM EDT Sun Jun 24 2018

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

.SYNOPSIS...
Issued at 253 AM EDT Sun Jun 24 2018

A wave of low pressure will track through the region today
producing some showers and perhaps a thunderstorm. A large area of
high pressure will build in behind it for Monday. This will result
in dry weather. A warm front moves in from the southwest on
Tuesday. Thus some rain will be possible then.

&&

.SHORT TERM...(Today through Tuesday)
Issued at 253 AM EDT Sun Jun 24 2018

Models are in relative agreement in tracking a shortwave eastward
through the CWA today. The best lift and moisture is focused over
northern zones mainly this morning. This is the region where I
will feature the highest POPs. Radar trends are supporting a
somewhat further south location of the showers...so I will bump up
POPs for central zones over the guidance. There is some slight
instability forecasted...so a storm or two is possible. The winds
will feature a northerly component especially on the backside of
the system. This will act to hold back temperatures today.

A large high pressure system ridges in from the northwest tonight
and Monday. This will support dry conditions. A decent amount of
sunshine looks likely for Monday...thus temperatures will likely
end up warmer for Monday.

This high pressure system will be on the move so that by
Tuesday...warm air advection will be underway. A mid level low and
associated warm front moves in during the day on Tuesday. Will
feature high POPs. With some instability forecasted...will feature
the risk for storms as well. The nose of a low level jet is shown
to reach into the CWA. Thus...a risk for heavier rain may develop.
Deep layer shear is forecasted to increase as well. Thus we will
need to monitor the risk for organized convection.



.LONG TERM...(Tuesday night through Saturday)
Issued at 253 AM EDT Sun Jun 24 2018

A sfc and upper level low pressure system will combine to bring
showers and thunderstorms Tuesday night into Wednesday. Dew point
values will reach well into the 60`s with precipitable water values
in the 1.5 to 2 inch range. Therefore some locally rain is possible.

There is also potential for some stronger convection Tuesday through
Tuesday night as deep layer wind shear ramps up. Potential for any
severe wx will be largely contingent on how much instability
develops.

Fair weather will return late Wednesday and Thursday as that system
moves east and a high pressure ridge builds in. A consensus of
latest medium range guidance continues to indicate that temperatures
will undergo a significant moderating trend late in the week into
next weekend as an upper level ridge amplifies over our region.
High temps by Friday through the weekend could easily reach the
lower to middle 90`s.

&&

.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1145 PM EDT Sat Jun 23 2018

A mix of MVFR/VFR conditions will continue overnight with MVFR due
to low clouds. IFR/LIFR conditions are also possible overnight
into Sunday morning mainly at KMKG where conditions remain LIFR at
the moment. Some showers will also redevelop overnight and Sunday
but the relatively best chance for those will be north of all the
terminals. Conditions will slowly improve to MVFR and then VFR
Sunday afternoon and evening.


&&

.MARINE...
Issued at 253 AM EDT Sun Jun 24 2018

Winds and waves are expected to remain below headline criteria
through Monday. Today winds of 15 to 20 knots from the north up
near Little an Big Sable Points are possible. This will be the
result of the wave of low pressure that tracks through the region.

&&

.HYDROLOGY...
Issued at 1223 PM EDT Sat Jun 23 2018

With locally heavy rainfall over the last 24 hours, most
locations along the Kalamazoo River are running near to above
normal for late June. The Grand River basin is running mainly near
normal, with the Muskegon River running near normal. Expected
rainfall over the next 24 hours will be highest across the
Muskegon River basin, where flows are lower with respect to normal
than other basins. Flooding is not expected.

For Tuesday and Wednesday, precipitable water values surge toward
the 1.8"-2.0" range. Any convection that develops could produce
locally heavy rainfall once again. Areas that currently have
saturated soils due to significant rains in recent days may be
prone to localized flooding if storms materialize.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...None.
&&

$$

SYNOPSIS...MJS
SHORT TERM...MJS
LONG TERM...Laurens
AVIATION...Laurens
HYDROLOGY...Hoving
MARINE...MJS



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