Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 201130

Area Forecast Discussion
National Weather Service Grand Rapids MI
730 AM EDT Tue Mar 20 2018


Issued at 318 AM EDT Tue Mar 20 2018

Cool dry weather is expected through Friday. Today is expected to
be the coolest and breeziest day of this week. A storm system is
likely to pass just south of our area Saturday. There is still a
slight chance of snow Saturday mostly near and south of I-94.


.SHORT TERM...(Today through Thursday)
Issued at 318 AM EDT Tue Mar 20 2018

Our biggest issue today will be just how warm it gets in the
afternoon. Otherwise with the Canadian high, centered over
Southern Hudson Bay into Wednesday a storm system tracking south
of Michigan today and up the East Coast Wednesday, we will have a
continued feed of cool, dry Canadian air.

We have a northern stream shortwave to our west digging southward
into the western Great Lake by Wednesday as a southern stream wave
tries to phase with the northern stream wave on Wednesday. That
results in another significant eastern CONUS storm. Here through
we will only have the upper trough coming through the area
Wednesday night and shortwave ridging follows by Thursday evening.
This will mean today will be the coolest day then a slow warm up
begins and continues through Thursday.

All of the precipitation with the southern stream system will stay
south of here and the northern stream shortwave has to little mid
level moisture to result in precipitation so dry conditions will

.LONG TERM...(Thursday night through Monday)
Issued at 318 AM EDT Tue Mar 20 2018

A high pressure ridge will remain in control of the wx pattern late
in the week and produce fair wx with seasonable temperatures for
this time of year Thursday night through Friday.

A low pressure system over the lower Ohio/TN valley regions will
bring potential for light snow over our southern fcst area Saturday
into Saturday night. However a consensus of latest medium range
guidance suggests that the more significant pcpn will stay south
across Indiana Saturday in an area of strong isentropic upglide to
the north of the warm front across the TN valley region.

A high pressure ridge anchored to the northeast of our region should
bring fair wx Sunday. Temperatures should undergo a slow moderating
trend late in the weekend into early next week.


.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
Issued at 730 AM EDT Tue Mar 20 2018

A narrow ribbon of MVFR cloud cover streaming in from Saginaw Bay
is occasionally reaching as far as GRR and MKG. This will likely
be the case through tonight. Otherwise the only other cloud layer
will be around FL200. Northeast winds will increase after sunrise
and boost gusts to around 25 kt. After sunset, winds will diminish
slightly but gusts could still occur.


Issued at 318 AM EDT Tue Mar 20 2018

Winds and waves will stay just under criteria for a Small Craft
Advisory (SCA)today and then winds diminish tonight and remain
lighter tomorrow. With winds from the Northeast today into this
evening the bigger waves will be well off shore. So, do not plan
to issue a SCA at this point.


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.




LONG TERM...Laurens
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