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Area forecast discussion 
National Weather Service Grand Rapids Michigan
626 am EDT Monday may 4 2015

Latest update...

issued at 314 am EDT Monday may 4 2015

A cold front will move through lower Michigan today bringing showers
and thunderstorms with it. After moving south over northern
Indiana...the front will move north Tuesday. Showers and storms will
remain in the forecast through Wednesday as the frontal boundary
moves across lower Michigan. Severe weather is not expected at this
time. A warm week is expected with highs in the 70s and 80s except
Tuesday when highs will reach the lower 60s.


issued at 626 am EDT Monday may 4 2015

I have updated our forecast for today to significantly decrease
the chance for having any precipitation once the remaining area of
showers moves out of this area by middle morning. There is
considerable middle level subsistence behind this shortwave and all of
our short range models...including all high resolution models show
this drying out of the middle levels after 09 am. There is some risk
the Interstate 69 area could see some convection re-develop this
afternoon but even that seems unlikely now. Most of the convection
this afternoon will near and south of intestate 80. In fact...I
would not be surprised to see a fair amount of sunshine over the
area by middle to late afternoon.


Short term...(today through wednesday)
issued at 314 am EDT Monday may 4 2015

Forecast concerns deal with the evolution of the frontal boundary
that will be moving through the County Warning Area today. The forecast hasn't
changed much and showers and storms are expected through Wednesday.

Radar shows showers and embedded storms moving across the County Warning Area at this time.
This activity is ahead of the cold front which is still over
Wisconsin. The echo pattern appears as a pseudo warm front aided by
the low level jet aimed at SW lower Michigan. Cloud tops are warming over Wisconsin
and we should see a general decrease in echo intensity toward
morning when the cold front approaches. Highest probability of precipitation this afternoon
will be over the southern County Warning Area as the front moves over northern

We/ll keep showers/storms in the grids tonight as the European model (ecmwf) shows a
wave developing on the boundary over southern Iowa and moving east.
The GFS/NAM Don/T really show the wave but do show some precipitation near
the boundary Tuesday. This boundary will lift north in response to a
deepening plains low. Tuesday will be the coolest day of the short
term with highs in the 60s. After the frontal boundary moves
north...temperatures will climb into the 70s Wednesday.

Long term...(wednesday night through sunday)
issued at 314 am EDT Monday may 4 2015

Expect above normal temperatures through the long term period. While
there is some threat for thunderstorms each day the chances seem
highest Saturday through Monday. There is some potential for strong
storms late in the weekend into early next week.

A closed upper low off the coast of the state of Washington and
southern British Columbia early this morning digs southeast into the
southwestern Continental U.S. By late this week. This builds an upper level
ridge over the eastern Continental U.S. Thursday into Friday. That should for
the most part keep the threat of showers down and increase the
chance for highs in the lower to middle 80s. There is a shortwave that
tries to come out of the western system Thursday but the energy for
that should mostly be west of Michigan. During the weekend a much
more powerful Pacific system boots the system over the southwest
into the central Continental U.S. By Sunday. It is in the Sunday to Monday time
frame our risk for stronger storms and heavy rain would be greatest.
Model agreement on this is reasonable but given how far out in time
this is... deals will surely change as we get closer to next weekend.

My bottom line is warm and mostly dry Thursday and Friday...showers
and thunderstorms Saturday into Monday.


Aviation...(for the 12z tafs through 12z Tuesday morning)
issued at 626 am EDT Monday may 4 2015

Once this area of convection ahead of the cold front clears the
area by 12z over the western sections and 15z over the eastern
sections the area of MVFR ceilings currently over Wisconsin will
follow for th 13z to 16z time frame. That will move out of the
area by 16z to 18z leaving mostly sunny skies and a northwest wind
around 10 knots for the remainder of the day. This evening should
see VFR conditions continue through around 06z. Then a wave on the
front will bring showers back to the area with lowering ceiling and


issued at 314 am EDT Monday may 4 2015

Scattered to numerous showers and thunderstorms are expected through
Wednesday. Outside of thunderstorms winds and waves will be below
Small Craft Advisory criteria.


issued at 1136 am EDT sun may 3 2015

Rivers are running well within banks and remain steady...if not
falling ever-so-slightly. Though flooding is not anticipated at
this time...the pattern becomes active over the course of the
upcoming week and we may see within bank rises.

Precipitation is expected to developed and progress from north to
south beginning late tonight. The frontal boundary responsible for
the precipitation will stall near the Southern Lower Michigan
border which will lead to some of the higher totals aligning along
and south of I-94. This front then returns north near midweek and
provides another decent shot at precipitation for central lower
Michigan during that time frame. Yet another round of wet weather
is poised to move through late in the week and into next weekend.

The main impacts would likely be minor and not really felt until we
get into the new work week. Locations that are already rain soaked
and receive any additional convective precipitation could see
minor ponding on roadways...or low lying areas that are typically
affected by heavier rain. An additional note is that we are dry now
and green-up is occurring in many locations. This will definitely
help in taking up a lot of the moisture that falls.


GRR watches/warnings/advisories...


short term...04
long term...wdm

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