Severe Thunderstorm Warning 8, NWS Grand Rapids, MI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
455 PM EDT SAT APR 25 2009

LATEST UPDATE...ALL SECTIONS EXCEPT LONG TERM AND AVIATION...

.SYNOPSIS...(455 PM EDT SAT APR 25 2009)
AN ACTIVE PERIOD OF WEATHER IS EXPECTED THE NEXT SEVERAL DAYS ACROSS
SOUTHWEST LOWER MICHIGAN AS A FRONTAL BOUNDARY OSCILLATES THROUGH
THE AREA. A COLD FRONT WILL DROP SOUTH OF THE AREA THIS EVENING AND
MOVE BACK NORTH AS A WARM FRONT ON SUNDAY. ANOTHER COLD FRONT WILL
PUSH THROUGH FROM THE WEST MONDAY NIGHT. SO...PERIODS OF SHOWERS AND
THUNDERSTORMS CAN BE EXPECTED THROUGH MONDAY NIGHT. RAINFALL OVER
THE COURSE OF THE NEXT FEW DAYS MAY PUSH INTO THE ONE TO TWO INCH
RANGE.

&&

.SHORT TERM...(455 PM EDT SAT APR 25 2009)
(TONIGHT THROUGH MONDAY NIGHT)
CONVECTIVE EVOLUTION WILL BE THE MAIN FORECAST CONCERN THROUGH THE
SHORT TERM...AS A FRONTAL BOUNDARY MOVES THROUGH THE REGION MULTIPLE
TIMES. A COLD FRONT WILL SLIP SOUTH THROUGH THE AREA TONIGHT...THEN
MOVE BACK NORTH AS A WARM FRONT ON SUNDAY. SUNDAY NIGHT AND MONDAY
SOUTHWEST LOWER MICHIGAN WILL BE IN THE WARM SECTOR ONCE AGAIN.
FINALLY...A COLD FRONT WILL SWEEP THROUGH THE AREA MONDAY NIGHT.
ROUNDS OF CONVECTION WILL LIKELY ACCOMPANY EACH FRONTAL PASSAGE
THROUGH THE FORECAST AREA.

THE FORECAST AREA IS NOT IN A SLIGHT RISK IN DAY TWO OR DAY THREE AT
THIS POINT...BUT THE STRENGTH OF THE LLJ SUNDAY EVENING AND SUNDAY
NIGHT IS A CONCERN. SUNDAY NIGHT A 50-60KT LLJ WILL BE IN PLACE
OVERHEAD...SO DAMAGING WIND GUSTS WILL BE A CONCERN IF ENOUGH
INSTABILITY CAN BE REALIZED.

PROBLEMATIC ISSUE WITH THE FORECAST IS THE AMOUNT OF CONVECTIVE
DEBRIS/RAIN THAT WILL BE IN PLACE IN ANY GIVEN FORECAST
PERIOD...WHICH WILL INHIBIT FURTHER DEVELOPMENT. AT THIS TIME...THE
TIME FRAMES TO KEY ON APPEAR TO BE SUNDAY EVENING/SUNDAY NIGHT AND
AGAIN ON MONDAY EVENING AHEAD OF THE COLD FRONT.

&&

.LONG TERM...(243 PM EDT SAT APR 25 2009)
(TUESDAY THROUGH SATURDAY)
THE MID RANGE MODELS ARE NOT IN GOOD AGREEMENT. THE GOING FORECAST
LOOKS TO BE FAVORING THE ECMWF. FEEL THAT THE GFS SOLUTION IS CLOSER
TO WHAT WILL HAPPEN. WITH SEVERE WEATHER ACROSS THE REGION TODAY AND
UNCERTAINTY WITH THE FORECAST... JUST LEANED THE GRIDS TOWARD THE
GFS SOLUTION. NO BIG CHANGES BEING MADE.

TUESDAY WILL SEE A COLD FRONT APPROACHING THE AREA WITH SHOWERS AND
THUNDERSTORMS. HIGH PRESSURE BUILDS IN TUESDAY NIGHT AND WEDNESDAY.
THIS FRONT WILL STALL SOUTH OF THE STATE. A LOW PRESSURE SYSTEM WILL
THEN MOVE FROM THE CENTRAL PLAINS JUST SOUTH OF THE AREA WITH
SHOWERS AND THUNDERSTORMS. THIS WILL KEEP THE FRONT IN THE REGION
AND PRECIPITATION AND CONVECTION ARE IN THE FORECAST THROUGH
SATURDAY.

WITH MAINLY ZONAL FLOW... TEMPERATURES WILL BE AT TO A LITTLE ABOVE
AVERAGE THROUGH THE EXTENDED PERIODS.

&&

.AVIATION...(455 PM EDT SAT APR 25 2009)
SHOWERS AND THUNDERSTORMS CONTINUE TO MOVE ACROSS SOUTHWEST LOWER
MICHIGAN THIS EVENING. THESE SHOWERS AND STORMS ARE ASSOCIATED WITH
A COLD FRONT THAT EXTENDS ACROSS THE REGION. THE FRONT IS SLOWLY
SLIDING SOUTHEAST AND IS EXPECTED TO STALL LATER TONIGHT. BEHIND THE
FRONT, SHOWERS AND THUNDERSTORMS CONTINUE TO DEVELOP ACROSS LAKE
MICHIGAN AS ANOTHER UPPER WAVE SLIDES EAST. WE WILL CONTINUE TO SEE
THE POSSIBILITY OF PRECIP THROUGH MUCH OF THE OVERNIGHT HOURS. DO
ANTICIPATE IFR TO LIFR CONDITIONS THROUGH 14Z SUN AS WARM FRONT
LIFTS NORTH ACROSS SITES. VISIBILITIES AND CLOUDS DECKS WILL
GRADUALLY INCREASE BY MID MORNING SUNDAY.

&&

.MARINE...(455 PM EDT SAT APR 25 2009)
A SMALL CRAFT ADVISORY CONTINUES INTO THIS EVENING AS WAVES REMAIN
UP A BIT FROM SOUTHWEST FLOW THE PAST 24 HOURS. WAVES WILL BE ON A
DOWN TREND TONIGHT AS THE FLOW GRADUALLY BECOMES OFF SHORE BEHIND A
SOUTHWARD SINKING COLD FRONT. WAVES WILL LIKELY BE FAIRLY SMALL IN
THE NEARSHORE WATERS INTO SUNDAY NIGHT...BEFORE SOUTHERLY FLOW KICKS
THINGS UP AGAIN.

&&

.HYDROLOGY...(455 PM EDT SAT APR 25 2009)
PERIODS OF SHOWERS AND THUNDERSTORMS OVER THE NEXT COUPLE OF DAY
WILL BRING THE AREA RAINFALL ON THE ORDER OF ONE TO TWO INCHES BY
TUESDAY. SOME LOCATIONS MAY HAVE ALREADY RECEIVED OVER A HALF AN
INCH OF RAIN...ESPECIALLY ACROSS CENTRAL LOWER MICHIGAN. STREAMFLOW
CONDITIONS ACROSS CENTRAL LOWER MICHIGAN ARE NEAR NORMAL AT THIS
POINT...SO RIVER UP THERE WILL LIKELY BE ABLE TO HANDLE THE
PRECIPITATION WITHOUT SIGNIFICANT ISSUES. IN THE SOUTH
HOWEVER...STREAMFLOW CONDITIONS ARE ALREADY HIGH AND ADDITIONAL
RAINFALL MAY HAVE MORE OF AN IMPACT. RIVER CONDITIONS WILL BE
MONITORED CLOSELY THIS EVENING AND NEW FORECASTS WILL LIKELY BE
FORTHCOMING.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY IN EFFECT THROUGH 00Z SUN FOR THE ENTIRE
NEARSHORE FROM ST. JOE TO MANISTEE.

&&

SYNOPSIS:     DUKE
SHORT TERM:   DUKE
LONG TERM:    IOD
AVIATION:     JB
MARINE:       DUKE
HYDROLOGY:    DUKE

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1123 PM EDT SAT APR 25 2009

MIZ037>040-043>046-050>052-056>059-064>067-071>074-260945-
MASON-LAKE-OSCEOLA-CLARE-OCEANA-NEWAYGO-MECOSTA-ISABELLA-MUSKEGON-
MONTCALM-GRATIOT-OTTAWA-KENT-IONIA-CLINTON-ALLEGAN-BARRY-EATON-
INGHAM-VAN BUREN-KALAMAZOO-CALHOUN-JACKSON-
1123 PM EDT SAT APR 25 2009

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

.DAY ONE...TODAY AND TONIGHT

A SLIGHT RISK OF SEVERE THUNDERSTORMS EXISTS THROUGH EARLY EVENING.
THE MAIN THREATS ARE DAMAGING WINDS AND LARGE HAIL. THUNDERSTORM
MOVEMENT WILL BE EAST NORTHEAST AT 35 TO 45 MPH. THE SEVERE WEATHER
THREAT WILL END BY 8 PM OR POSSIBLY EARLIER WITH THE PASSAGE OF A
COLD FRONT.

ADDITIONAL SHOWERS AND THUNDERSTORMS WILL OCCUR TONIGHT WITH LOCALLY
HEAVY RAINFALL POSSIBLE.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

THE THREAT FOR THUNDERSTORMS WILL LIFT NORTHWARD DURING THE DAY
SUNDAY AS A WARM FRONT PUSHES THE AREA OF STORMS NORTH TOWARD
ROUTE 10 BY EVENING. THESE STORMS ARE NOT EXPECTED TO BE SEVERE AT
THIS TIME.

ON MONDAY A COLD FRONT WILL PUSH EAST ACROSS THE AREA LATE IN THE
DAY AND BRING THE RISK OF STRONG TO SEVERE THUNDERSTORMS.

THURSDAY AND FRIDAY ANOTHER STORM SYSTEM WILL BRING BACK THE
THREAT FOR THUNDERSTORMS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL BE NEEDED TODAY.

LMZ844>849-260945-
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-
1123 PM EDT SAT APR 25 2009

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

.DAY ONE...TODAY AND TONIGHT

CONDITIONS HAZARDOUS FOR SMALL WATER CRAFT ARE EXPECTED THROUGH
THIS EVENING DUE TO STRONG SOUTHWEST WINDS THAT WILL VEER TO THE
NORTHWEST. IN ADDITION NUMEROUS THUNDERSTORMS ARE EXPECTED THIS
AFTERNOON INTO THE EARLY EVENING. LOCALLY HIGH WINDS AND WAVES ARE
POSSIBLE IN AND NEAR THE THUNDERSTORMS. AREAS OF FOG ARE
POSSIBLE AS WELL DUE TO WARM AIR MOVING OVER THE COLD LAKE.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

THE AREA OF THUNDERSTORMS WILL LIFT BACK NORTH ACROSS THE NEAR
SHORE WATERS SUNDAY. THE THREAT WILL MOSTLY BE NORTH OF LITTLE
SABLE POINT BY EVENING. GUSTY WINDS AND INCREASED WAVES HEIGHTS ARE
THE PRIMARY THREAT.

ADDITIONAL STORMS ARE EXPECTED WITH THE COLD FRONT MONDAY AFTERNOON
INTO THE EVENING. GUSTY WINDS AND HIGH WAVES ARE ONCE AGAIN
POSSIBLE. ONCE THE COLD FRONT COMES THROUGH NORTHWEST WINDS WILL
BUILD THE WAVE HEIGHTS TO THE POINT WERE THEY WILL BE HAZARDOUS FOR
SMALL WATER CRAFT. THESE CONDITIONS WILL SUBSIDE BY TUESDAY
EVENING.

MORE STORMS ARE POSSIBLE LATER IN THE WEEK.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS POSSIBLE THIS AFTERNOON INTO TONIGHT.

MEADE

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
539 PM EDT SAT APR 25 2009

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

0514 PM     NON-TSTM WND DMG MARSHALL                42.27N 84.96W
04/25/2009                   CALHOUN            MI   COUNTY OFFICIAL

            NUMEROUS TREES DOWN THROUGH OUT COUNTY.

&&

GWETZEL

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
543 PM EDT SAT APR 25 2009

MIZ051-052-058-059-066-252245-
CLINTON-EATON-GRATIOT-IONIA-MONTCALM-
543 PM EDT SAT APR 25 2009

...SIGNIFICANT WEATHER ADVISORY...

AT 542 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
STRONG THUNDERSTORMS ALONG A LINE EXTENDING FROM 10 MILES EAST OF
STANTON TO 6 MILES SOUTHEAST OF PORTLAND...MOVING EAST AT 55 MPH.

* LOCATIONS IN THE PATH OF THESE STORMS INCLUDE...

  FERRIS TWP...         CEDAR LAKE...         VICKERYVILLE...
  BUTTERNUT...          FENWICK...            CRYSTAL...
  VESTABURG...          MCBRIDE...            SHERIDAN...
  EDMORE...             STANTON...            MUIR...
  LYONS...              PALO...               PEWAMO...
  PORTLAND...           IONIA...              CARSON CITY...

THESE STORMS ARE CAPABLE OF PRODUCING SMALL HAIL...STRONG WIND
GUSTS...OCCASIONAL CLOUD TO GROUND LIGHTNING...AND BRIEF DOWNPOURS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

GUSTY WINDS MAY CAUSE SMALL BRANCHES TO BE BLOWN DOWN...AND LOOSE
OBJECTS TO BLOW AROUND. STAY AWAY FROM HIGH OBJECTS OUTDOORS SUCH AS
TREES. SEEK SHELTER IN A STURDY STRUCTURE UNTIL THESE STORMS HAVE
PASSED.

&&

LAT...LON 4276 8465 4278 8510 4346 8511 4345 8437
      4297 8436
TIME...MOT...LOC 2143Z 264DEG 49KT 4326 8486 4280 8483

MEADE

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
554 PM EDT SAT APR 25 2009

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

0520 PM     TSTM WND DMG     2 W LESLIE              42.45N 84.47W
04/25/2009                   INGHAM             MI   TRAINED SPOTTER

            NUMEROUS POWER POLES DOWN. 1/2 INCH HAIL REPORTED IN
            LESLIE.

&&

GWETZEL

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