Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 160511

Area Forecast Discussion
National Weather Service Grand Rapids MI
1211 AM EST Thu Feb 16 2017


Issued at 256 PM EST Wed Feb 15 2017

a ridge of high pressure will move over the state tonight. We`ll see
snow showers begin to diminish as drier and warmer air aloft arrive.
The next few days will be dry and warmer as temperatures climb into
the 50s by Saturday.


.SHORT TERM...(This evening through Friday night)
Issued at 256 PM EST Wed Feb 15 2017

Forecast concerns are minimal this afternoon and mainly deal with
the end of the current snow shower activity.

Latest sfc analysis shows a high pressure ridge extending from the
MN arrowhead south across western IA. This ridge will move over the
Lower Michigan tonight and push the deep upper currently in place to
the east. Warmer air on the back side of the ridge will begin moving
across the lake tonight and we`ll see snow showers diminish as a
result. We should be looking at generally dry conditons Thursday; a
few lingering flurries along the lake shore remain possible.
Thursday will still be chilly with highs in the lower 30s. However,
a warm front will lift north early Friday and temps will climb into
the 40s with 50s expected Saturday. Subsidence from the upper ridge
will result in some sunshine over the weekend.

.LONG TERM...(Saturday through Wednesday)
Issued at 256 PM EST Wed Feb 15 2017

Only weather maker in the extended is a northern stream low that
swings a weak front through Monday night or Tuesday. Still uncertain
on the timing and my preference is to go with the slower ECMWF given
shortwave ridging ahead of the low may be slower to yield to precip.
The trends are for less precip as this low remains separate from the
southern stream and so there is not as much Gulf moisture drawn
north. P-type looks to be all rain even up north as suggested by
thickness tools and forecast thermal profiles.

Another area of model disagreement occurs Tuesday night and
Wednesday as the GFS brings in a quick return of moisture with sfc
low moving in from the west. In contrast, the ECMWF has sfc ridging
during this period with the low minoring out west of Lower Michigan
on Wednesday as a more consolidated system forms over the Plains.
The blended POPs were lowered here with chance POPS spread out
across Tuesday night and Wednesday. Expect mostly rain with this,
although P-type could be an issue, especially up north, as there are
hints that some cold air is available via sfc ridging extending into
Lower Michigan from an arctic high centered near Hudson Bay.


.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1106 PM EST Wed Feb 15 2017

The low level moisture is forecasted to decrease through Thursday.
This will likely act to keep conditions VFR. A few snow showers
may persist to start the period...but they should be gone by 09Z.
Isolated impacts to MVFR may occur until then.


Issued at 256 PM EST Wed Feb 15 2017

Winds and waves will gradually decrease tonight as high pressure
moves overhead. The small craft advisory remains in effect through
late tonight.


Issued at 131 PM EST Wed Feb 15 2017

River levels continue above normal, but no flooding is expected
into next week. Little precipitation is expected, so river levels
should fall into next week.


LM...Small Craft Advisory until 5 AM EST Thursday for LMZ844>849.



LONG TERM...Ostuno
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