Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 162020

Area Forecast Discussion
National Weather Service Grand Rapids MI
318 PM EST Mon Jan 16 2017

Synopsis/Short Term/Long Term/Marine

Issued at 318 PM EST Mon Jan 16 2017

Low pressure moving across northern Indiana will produce a mix of
rain, snow, sleet, and freezing rain tonight over southwest Lower
Michigan. Ice accumulations around a tenth of an inch are possible
tonight north of I-96. After the low moves by Tuesday, we`ll see see
a couple of dry days. Temperatures will be above normal the rest of
the week with highs mainly in the 40s.


.SHORT TERM...(This evening through Wednesday night)
Issued at 318 PM EST Mon Jan 16 2017

Forecast concerns deal with p-type as low pressure moves across
Lower Michigan early Tuesday.

Radar continues to be active this afternoon with echos aoa 25 dbz
over the cwa. A mix of rain to the south and freezing rain/sleet in
the central/north will continue through tonight. Regional radar
shows a large area of pcpn extending from the low in northeast
Kansas east through Pennsylvania. We have quite a bit of pcpn to go
through yet.  Local observations have climbed to 36 in Kalamazoo and
35 in Battle Creek. It`s worth noting that MOS temps have been 2-5
degrees too high compared to actual temps this afternoon. As night
approaches we may see a degree or so decrease in temps and kept that
in mind as it related to current headlines. We have canceled the
freezing rain advisory in Allegan, Barry, and Calhoun counties as
temps there are the warmest. The remainder of the headlines are
unchanged. It`s possible that additional counties may be canceled
this evening depending on temperature trends. Until then, thermal
profiles favor freezing rain and perhaps some sleet. One thing to
consider is that sfc/roadway temps will be a degree or two colder
than the standard asos/awos observation. Temps are progd to rise a
bit overnight and pcpn over most of the cwa will turn to rain. The
exception will be the far northeast counties where freezing
rain/sleet will linger into Tuesday morning.

Once the low moves across the southern cwa Tuesday morning, we`ll
see pcpn end from northwest to southeast. Tuesday night through
Wednesday night look dry as high pressure moves over the Ohio

Short range models continue to

.LONG TERM...(Thursday through Monday)
Issued at 318 PM EST Mon Jan 16 2017

Confidence is fairly high that the area will see a fairly mild
period through the long term by January standards, with a couple
better chances of rain through next Monday.

The mild air expected through the period results from the northern
branch of the upper jet remaining mainly north and west of the
CONUS. We will see an upper ridge controlling our weather initially,
bringing some sun and mild temps for Thu. A threat of some mainly
rain will come in later Thu night into Fri as the upper system
currently across the Four Corners region will lift up toward the
area. This will weaken as it moves toward the upper ridge in place.
It will draw some Gulf moisture north toward the area.

We will see a break in the better chances for rain then for much of
the weekend, before they move back in for early next week. The ridge
will re-establish itself over the area as a strong Pacific jet
brings a fairly large amplitude trough over the Western U.S.. This
will keep the mild air in over the area, with 50 degrees not out of
the question next weekend.

Rain chances will then move back in by Mon, as the next Wrn trough
lifts out of the wrn states and toward the area. This will bring
another surge of warm and moist air up from the Gulf.


.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 1243 PM EST Mon Jan 16 2017

Our two main issues with the 18z fcsts are determining the timing
of the transition from freezing rain to rain, and then the
increase of IFR and lower conditions into the area.

As of 1730z, temperatures have pretty much come up above freezing
at the I-94 corridor terminals. This means that pcpn at these
sites should remain just rain from this point onward. The I-96
corridor terminals are all still freezing rain, and we expect
temperatures to warm above freezing by 19-20z. This will change
any fzra over to rain.

It appears now that based on the position of the IFR and lower
conditions just south of the area, that this will lag the change
over to rain by a couple of hours or so. We expect conditions to
drop from 20-22z into the IFR category, and then dropping further
after that. LIFR looks likely most of the time frame then, with
VLIFR very possible. In fact, data suggests that once the more
widespread rain moves out around daybreak Tue morning, conditions
may drop a bit more after that.


Issued at 318 PM EST Mon Jan 16 2017

The weak pressure gradient will continue through Wednesday resulting
in fairly light winds and low wave heights.


Issued at 122 PM EST Sat Jan 14 2017

Rivers are running above normal across the area due to rain, melted
snow and ice jams. The Grand River at Robinson Township has an
active warning for minor flooding. Multiple sites also have active
advisories. A period of colder than normal temperatures through the
weekend may allow river ice to thicken. Next week looks warmer than
normal with highs possibly reaching the 50s. This could melt the
river ice and allow the rivers to flush out.


MI...Freezing Rain Advisory until 2 AM EST Tuesday for MIZ050-
056>059-     067.

     Winter Weather Advisory until 9 AM EST Tuesday for MIZ037>040-



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