Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Grand Rapids Michigan
1246 PM EST Thursday Dec 25 2014

Latest update...
aviation

Synopsis...
issued at 310 am EST Thursday Dec 25 2014

Low pressure that brought rain and some light snow to west Michigan
continues to move away and will be replaced by a ridge which will
generate dry weather for a day or so. Light rain will move back into
west Michigan Friday night and Saturday ahead of a cold front that
will move through Saturday. Temperatures will fall back to the 30s
and 20s from Sunday through middle week amid low chances of light snow.

&&

Short term...(today through saturday)
issued at 310 am EST Thursday Dec 25 2014

Forecast concerns are minimal this morning and mainly deal with the
next system moving in Friday night and Saturday.

Kgrr-88d shows light snow showers moving across the central County Warning Area but
echos have been diminishing over the past few hours as the upper
trough axis moves east across lower Michigan. Not looking for much
after middle morning and have dry grids this afternoon.

South winds will develop tonight and temperatures will warm Friday.
High pressure over the southeast US will push highs into the lower
to middle 40s under partly sunny skies. The next chance of rain arrives
Friday night and Saturday as a cold front approaches. Models are
hinting a wave of low pressure will ride northeast along the frontal
boundary and push light rain into lower Michigan by midnight Friday
night. Light rain will continue Saturday but may become mixed with
light snow during the afternoon across the northern County Warning Area.

Long term...(saturday night through wednesday)
issued at 310 am EST Thursday Dec 25 2014

To start the long term period...temperatures will initially be warm
enough to warrant a r/S mix for the Jackson to Lansing region as a
low pressure system tracks through Michigan. Cold air advection
strengthens on the backside of this departing system...so by 06z sun
what precipitation is left behind...should be snow. Temperatures do
not cool down enough to warrant widespread lake effect snow Sunday
into Monday...so only very low probability of precipitation forecasted.

High pressure ridges in for Tuesday. This will act to keep any snow
shower activity to a minimum. A cold front arrives for Wednesday.
This will act to lower the temperatures into the middle part of the
week.

&&

Aviation...(for the 18z tafs through 18z Friday afternoon)
issued at 1246 PM EST Thursday Dec 25 2014

Aviation impacts over the next 24 hours will be much less than the
past 24 hours have had. MVFR ceilings of 1500-2500 feet are currently
impacting the area. We are expecting a clearing line across eastern
Illinois/WI and Lake Michigan to advance through the area later this
afternoon and early this evening. Winds gusts of 20-25 knots will
continue until sunset and will then diminish while becoming south-southwest.

There are some indications that after the low clouds clear
out...that some of them may try to expand back into the northern
portions of the area late tonight near a frontal system to our
north and with somewhat of an onshore flow off of Lake Michigan.
Winds remaining up around 5-10 knots will limit fog potential...
but could help low clouds redevelop. We have added a 2500 feet deck
back into kmkg around 10z Friday...however the confidence in this is
low at this time.

&&

Marine...
issued at 310 am EST Thursday Dec 25 2014
we extended the Small Craft Advisory through Friday. Waves should remain above 3 feet
through middle afternoon before decreasing to 2 to 4 feet by evening.



&&

Hydrology...
issued at 310 am EST Thursday Dec 25 2014

Flood advisories continue for the Looking Glass river near Eagle...
Sycamore Creek at Holt... and the Maple River at Maple Rapids. Only
minor lowland flooding is expected as these will crest below
bankfull. Additional appreciable precipitation is not expected today or
Friday.

&&

GRR watches/warnings/advisories...
Michigan...none.
Lm...Small Craft Advisory until 6 PM EST Friday for lmz844>849.

&&

$$

Synopsis...93
short term...93
long term...mjs
aviation...njj
hydrology...93
marine...93

National Weather Service Glossary of Abbreviations