Special Weather Statement, NWS Grand Rapids, MI

Area Forecast Discussion
National Weather Service Grand Rapids MI
757 PM EDT FRI AUG 12 2016

LATEST UPDATE...
Aviation

.SYNOPSIS...
Issued at 326 PM EDT Fri Aug 12 2016

A heavy rain threat exists tonight mainly along and south of I-96.
Showers and thunderstorms capable of producing heavy rain will
continue into Saturday morning. After low pressure passes through,
drier air will move in for the latter part of the weekend and early
next week.

&&

.SHORT TERM...(This evening through Sunday night)
Issued at 326 PM EDT Fri Aug 12 2016

Forecast concerns deal with the heavy rain threat tonight. Heavy
rainfall fell early this morning south of I-96. Many locations
received over an inch and a couple exceeded 2 inches. The south flow
that is in place across the Great Lakes will continue tonight as the
low level jet increases to 35 knots by Saturday morning. A sfc low
with upper support is progd to cross the lake tonight and will
encounter a very moist atmosphere with pwats between 2.4 and 2.8
inches. The resulting showers and storms that develop will have the
potential for producing torrential rain. Would not be surprised to
see additional rainfall over 2 inches tonight. As such we issued a
flood watch through 8am Saturday. Shear values increase to 30-35
knots tonight so a strong or severe storm can't be ruled out either.

The weather will quiet down Saturday afternoon after the low moves
through. Drier and slightly cooler air will move into the state
Saturday and highs Saturday and Sunday will be in the lower 80s.
Despite the cooler air, humid conditions will continue since
dewpoints will only fall to the mid 60s.

.LONG TERM...(Monday through Friday)
Issued at 326 PM EDT Fri Aug 12 2016

It is looking more and more like this will end up being a wet period
for Southwest Michigan.  It will likely be warmer than normal
through most of this period too.

As I have been writing about for the past few days that tropical
system over northern Gulf, near New Orleans, which has been moving
little over the past few days will get brought north but a digging
northern stream trough and being on the west side of the bermuda
high. Now the ECMWF is once again bringing the system into Southwest
Michigan in Tuesday into Wednesday time frame. The GFS ensembles
continue to support this system being brought northward into
Southwest Michigan, as it has for the past few days. I would plan on
Tuesday being a very wet day in Southwest Michigan.

Once that system is through the trailing upper trough brings another
period of showers and thunderstorms to the area. It will also warm
it up here for a few days. This would mean only Monday would be a
rain free day.

&&

.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 757 PM EDT Fri Aug 12 2016

Widespread MVFR conditions this evening should be going down to
IFR later tonight as heavy rain is expected to move in. IFR and
periods of LIFR will continue into Saturday morning with
improvement to VFR from west to east on Saturday afternoon.

&&

.MARINE...
Issued at 326 PM EDT Fri Aug 12 2016

Outside of thunderstorms, marine conditions will be fairly tame.
High pressure building into the Great Lakes Saturday will cause
waves to build to 1 to 3 feet.

&&

.HYDROLOGY...
Issued at 352 PM EDT Fri Aug 12 2016

Training moderate/heavy rain showers and storms occurred over
portions of Allegan and Barry counties early Friday morning (and
now also this afternoon). Where the most persistent heavy rain
fell, rates over 1 inch per hour were measured, and 1 to 2 inches
of rain in a 3-hour period was common over the larger area. After
12 days of dry weather, this rain was a a welcome sight and mostly
absorbed by the ground. There was some standing water on streets
noted in Allegan County Friday afternoon.

Confidence in localized flood potential has increased since
yesterday, as both global and mesoscale models are advertising
widespread rain occurring in multiple batches. Deep tropical
atmospheric moisture will be over the area, with precipitable
water values at least 2.0 to 2.25 inches. These PW values are in
the range of daily records for this time of year based on the DTX-
area upper air sounding climatology (since 1948). Conditionally
unstable lapse rates in place this afternoon will tend to
transition to moist neutral overnight. In the presence of moderate
lifting associated with a frontal wave, multiple rounds of heavy
rain appear possible Friday afternoon into Saturday morning.

While the ground is generally quite dry, rain this this morning
and afternoon is conditioning it to be less accommodating to any
additional heavy rain that may fall overnight. Also of note is
that tonight's convection may tend to be lower-topped with less
lightning, however can still produce copious rainfall rates via
warm rain processes (collision-coalescence). As such, there is
some concern for those out driving in heavy rain in the dark, as
they may encounter flooded roads amidst low visibility. Standing
water on roads will tend to occur in urban areas and low spots
with slow drainage.

&&

.GRR Watches/Warnings/Advisories...
MI...Flood Watch through Saturday morning for MIZ056>059-064>067-
     071>074.

LM...None.
&&

SYNOPSIS...04
SHORT TERM...04
LONG TERM...WDM
AVIATION...Ostuno
HYDROLOGY...CAS
MARINE...04

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
354 AM EDT FRI AUG 12 2016

MIZ037>040-043>046-050>052-056>059-064>067-071>074-130800-
MASON-LAKE-OSCEOLA-CLARE-OCEANA-NEWAYGO-MECOSTA-ISABELLA-MUSKEGON-
MONTCALM-GRATIOT-OTTAWA-KENT-IONIA-CLINTON-ALLEGAN-BARRY-EATON-
INGHAM-VAN BUREN-KALAMAZOO-CALHOUN-JACKSON-
354 AM EDT FRI AUG 12 2016

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHWEST LOWER
MICHIGAN.

.DAY ONE...TODAY AND TONIGHT

RAIN WILL BE HEAVY AT TIMES THROUGH TONIGHT. AN ELEVATED RISK FOR
FLOODING EXISTS. URBAN AND POOR DRAINAGE AREAS LOOK MOST PRONE.
IF THE THUNDERSTORMS REPEAT OVER THE SAME AREA...SMALLER STREAMS
AND RIVERS COULD SEE FLOODING AS WELL.

A MARGINAL RISK FOR SEVERE WEATHER EXISTS...MAINLY ALONG AND SOUTH
OF A MUSKEGON TO LANSING LINE. DAMAGING WINDS ARE THE PRIMARY
RISKS.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

THE HEAVY RAIN COULD PERSIST INTO EARLY SATURDAY MORNING WITH
FLOODING POSSIBLE.

NON SEVERE THUNDERSTORMS ARE POSSIBLE TUESDAY INTO THURSDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED INTO TONIGHT.

LMZ844>849-130800-
ST JOSEPH TO SOUTH HAVEN MI-SOUTH HAVEN TO HOLLAND MI-
HOLLAND TO GRAND HAVEN MI-GRAND HAVEN TO WHITEHALL MI-
WHITEHALL TO PENTWATER MI-PENTWATER TO MANISTEE MI-
354 AM EDT FRI AUG 12 2016

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHWEST LOWER
MICHIGAN.

.DAY ONE...TODAY AND TONIGHT

THUNDERSTORMS COULD CONTAIN GUSTY WINDS AND FREQUENT CLOUD TO
WATER LIGHTNING STRIKES. WAVES COULD BE LOCALLY HIGHER NEAR AND
THUNDERSTORMS.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

NON SEVERE THUNDERSTORMS ARE POSSIBLE TUESDAY INTO THURSDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED INTO TONIGHT.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
745 PM EDT FRI AUG 12 2016

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0744 PM     HEAVY RAIN       2 W ADA                 42.95N 85.53W
08/12/2016  M2.67 INCH       KENT               MI   NWS EMPLOYEE

            ONE HOUR RAINFALL BETWEEN 315 PM AND 415 PM. DAILY RAIN
            TOTAL 2.75 THROUGH 7 PM.

&&

JK

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1014 PM EDT FRI AUG 12 2016

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0210 PM     TORNADO          3 NW FENNVILLE          42.62N 86.15W
08/12/2016                   ALLEGAN            MI   NWS STORM SURVEY

            EF-0 TORNADO TOUCHED DOWN BRIEFLY NEAR RIVERSIDE ROAD.
            ONE OUTBUILDING WAS DESTROYED. TWO HOMES HAD MINOR SIDING
            OR ROOFING DAMAGE FROM DEBRIS AND FALLEN TREES.
            SIGNIFICANT TREE DAMAGE ALONG THE PATH THAT WAS ABOUT ONE
            QUARTER MILE LONG AND 25-50 YARDS WIDE.

&&

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1040 PM EDT FRI AUG 12 2016

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1035 PM     HEAVY RAIN       3 W ZEELAND             42.81N 86.08W
08/12/2016  M1.78 INCH       OTTAWA             MI   TRAINED SPOTTER

            DAILY RAINFALL TOTAL THROUGH 10 PM.

&&

JK

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
114 AM EDT SAT AUG 13 2016

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0100 AM     HEAVY RAIN       PAW PAW                 42.22N 85.89W
08/13/2016  M3.50 INCH       VAN BUREN          MI   TRAINED SPOTTER

            .

&&

OSTUNO

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
121 AM EDT SAT AUG 13 2016

MIZ066-073-130615-
EATON-CALHOUN-
121 AM EDT SAT AUG 13 2016

...A STRONG THUNDERSTORM WILL AFFECT SOUTHWESTERN EATON AND CENTRAL
CALHOUN COUNTIES...

AT 121 AM EDT...A STRONG THUNDERSTORM WAS LOCATED OVER BROWNLEE
PARK... MOVING NORTHEAST AT 25 MPH.

WINDS IN EXCESS OF 40 MPH ARE POSSIBLE WITH THIS STORM.

LOCATIONS IMPACTED INCLUDE...
ALBION...MARSHALL...BATTLE CREEK...BELLEVUE...LEVEL PARK-OAK PARK...
BROWNLEE PARK...MARENGO...OLIVET AND CERESCO.

LAT...LON 4232 8530 4235 8530 4242 8514 4242 8507
      4245 8507 4253 8491 4220 8473 4213 8519
TIME...MOT...LOC 0521Z 245DEG 21KT 4230 8517

MJS