Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 191923

Area Forecast Discussion
National Weather Service Grand Rapids MI
323 PM EDT Mon Mar 19 2018

Synopsis/Short Term/Long Term/Marine/Hydro

Issued at 323 PM EDT Mon Mar 19 2018

A quiet and cool week is expected across the area as the main storm
track will stay south of the area through Friday. Dry air will also
continue to feed in over the area, helping to keep the area dry.

A chance of snow will develop on Saturday and linger into Saturday
night with a developing storm system to our South and West. The main
area of precipitation will likely stay south of the area, but a
chance will remain.


.SHORT TERM...(This evening through Wednesday night)
Issued at 323 PM EDT Mon Mar 19 2018

Dry weather is expected through the short term. The main upper jet
will remain well south of the area. This will keep the system over
MO this afternoon south of the area, along with the confluent NW
flow aloft over our area. In addition, a dry NE flow will continue
to pump in very dry air in from NE Canada.

The only fly in the ointment would be some possible lake effect
clouds that could affect the ern portion of the area. The air is so
dry however, that we expect only some clouds in the worst case
scenario at this time.

Temps will remain cool and slightly below average through Wed with
the feed of cool and dry air feeding in from Canada.

.LONG TERM...(Thursday through Monday)
Issued at 323 PM EDT Mon Mar 19 2018

The main feature in the long term is the possible s pcpn from a
system that will be moving through somewhere in the region for the
Sat/Sat night time frame.

Quiet weather will rule for Thu through Fri night for the area with
slowly moderating temperatures. We will see the fairly amplified
upper ridge over the Plains slowly build toward the area.
Temperatures will slowly warm as the feed of cool and dry air
weakens, and the stronger sun angle moderates the air mass.

We have maintained a chance of mainly snow for the srn half of the
area from Sat through Sat night. We will see a low organize to the
lee of the Rockies later on Fri as upper energy ejects out of the
long wave western trough. Eventually it will tap Gulf warmth and
moisture, and battle with colder air funneling down from Canada.
This will set up stronger fgen, and expand pcpn.

Models are in fairly good agreement that the front/sfc low will end
up tracking toward the Ohio River. That is a fairly decent distance
from our area to provide decent amounts of pcpn here. We feel that
as is typical with the models this far out, the dry air is not
represented accurately, and it will eat away at the pcpn that tries
to form this far north. We are leaving some chcs of pcpn in for the
southern areas. This will likely be mostly snow if it does make it
this far North.

Once the Sat system moves by, upper ridging will likely build back
in and bring more dry weather to the area into next Mon.


.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 116 PM EDT Mon Mar 19 2018

Only real impact to aviation operations over the next 24 hours
will be wind gusts during the daylight hours. We expect wind gusts
up to around 25 knots until about 00z tonight, and then after 14z
on Tue once diurnal mixing gets going. A wind of around 10-12
knots will likely remain up through the night, with no gusts

Conditions should remain VFR at all sites. We can not rule out a
little bit of lake stratocumulus cloud cover coming from Lake
Huron with the NE flow. The air is so dry though that the clouds
should remain quite limited, if it happens at all.


Issued at 323 PM EDT Mon Mar 19 2018

Brisk East/Northeast winds will continue through Wednesday with a
decent pressure gradient in place. Winds appear that they will
approach Small Craft Advisory, but will probably stay just under
criteria with the stable layer over the water, and the offshore flow.


Issued at 323 PM EDT Mon Mar 19 2018

Dry weather through the end of the week will ensure that river
levels continue declining. The Portage River at Vicksburg will
continue to remain elevated for a few days yet, however. River
levels should remain near to below normal for the foreseeable future.




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