Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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117
FXUS63 KGRR 161148
AFDGRR

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

LATEST UPDATE...
Aviation

.SYNOPSIS...
Issued at 327 AM EST Thu Feb 16 2017

After a seasonably cold day today, a significant warmup will
commence Friday and persist well into next week. Highs in the 50s
will be frequent during this time particularly over southern Lower
Michigan. Dry conditions will persist through the weekend followed
by a chance for rain showers during the early part of next week.

&&

.SHORT TERM...(Today through Saturday)
Issued at 327 AM EST Thu Feb 16 2017

No significant changes to the forecast or concerns during the
period.

.LONG TERM...(Saturday night through Wednesday)
Issued at 327 AM EST Thu Feb 16 2017

The main challenge in the long term deals with the timing of any
showers.  Overall the confidence is lower than usual given that the
models are having some issues with initializing the upper jet over
the Western Pacific.  This jet breaks down into many smaller jet
streaks with time.  Timing these smaller features will be a
challenge going forward.

The long term period starts out with a sharpening mid level ridge
tracking eastward through the Great Lakes region Saturday Night into
Monday. Clouds will be thickening up especially as the ridge goes by
on Monday.  A low level jet is shown to arrive Monday or Monday
Night. That feature will act to draw some Gulf Moisture into the
CWA. There could be showers with the arrival of the low level
jet...especially over western parts of the CWA Monday Night as a
mid level wave flattens the ridge over the region leading to
height falls.

I will keep the pattern warmer than normal and unsettled going
through the middle part of the week.  Mid level west to southwest
flow is shown.  The GFS does show another shortwave moving in for
Wednesday into Wednesday Night...while the High Res Euro brings a
ridge in.  Despite the ridge...the High Res Euro does bring in a
higher pwat airmass along with elevated instability by Thursday.
Will keep the mention of mostly showers going.

&&

.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
Issued at 648 AM EST Thu Feb 16 2017

We continue to see lake effect clouds with occasional light snow
affecting mainly the inland terminals, but don`t expect this to
last much longer. Both visibility and ceilings should stay above
IFR / fuel alternate thresholds. There may be a period of ceilings
dropping close to 2000 ft agl at KGRR and KLAN this morning.
After 18z, there is much better certainty for VFR conditions
across the area.

&&

.MARINE...
Issued at 327 AM EST Thu Feb 16 2017

Have cancelled the small craft advisory. Winds and waves will be
greatly reduced today as surface high pressure becomes established
over the area. Conditions are expected to remain below small
craft advisory criteria through the weekend.


&&

.HYDROLOGY...
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.

&&

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

$$

SYNOPSIS...TJT
SHORT TERM...TJT
LONG TERM...MJS
AVIATION...TJT
HYDROLOGY...63
MARINE...TJT



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