Severe Thunderstorm Warning 145, NWS Grand Rapids, MI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
345 PM EDT WED SEP 6 2006

.SHORT TERM...
AS EXPECTED...ISOLATED THUNDERSTORMS DEVELOPED THIS AFTERNOON...SOME
REACHING SEVERE LEVELS. AT THIS POINT...WE HAVE NOT ATTAINED SEVERE
REPORTS FROM THE TWO WARNINGS...BUT THE ELEVATED CORES WERE HIGH
ENOUGH FOR SEVERE HAIL. EXPECT THE ISOLATED SHOWERS AND STORMS TO
CONTINUE INTO THE EVENING BEFORE DISSIPATING TOWARD SUNSET OR
SHORTLY THEREAFTER. OVERNIGHT EXPECT A REPEAT OF THE AREAS OF FOG
ONCE AGAIN...GIVEN GOOD RADIATIONAL COOLING CONDITIONS. AFTER
TONIGHT...FOCUS IN THE SHORT TERM SWITCHES TO THE COLD FRONT THAT IS
PROGD TO DROP INTO THE AREA FROM THE NORTH FRIDAY AND FRIDAY NIGHT.
THE MODELS HAVE GOTTEN A BIT CLOSER IN THERE SOLUTIONS REGARDING
POSITION.

ON THURSDAY...THE COLD AIR REMAINS AT 500MB/S AND THERE IS A WEAK
SHORTWAVE SWINGING THROUGH THE AREA. THE 500MB AIR IS SLIGHTLY
WARMER HOWEVER AND HAVE DECIDED TO MAINTAIN THE DRY FORECAST. WE
WILL NEED TO MONITOR THE POTENTIAL FOR PRECIPITATION THURSDAY
AFTERNOON THOUGH AS WE COULD HAVE A REPEAT PERFORMANCE OF WHAT HAS
OCCURRED THE LAST TWO DAYS.

THURSDAY NIGHT...SHOULD BE THE MOST QUIET PERIOD OF THE SHORT TERM
AS WEAK RIDGING SLIDES OFF TO THE SOUTH AND SOUTHERLY FLOW TAKES
OVER. EXPECT PRECIP ASSOCIATED WITH THE APPROACHING FRONT TO REMAIN
NORTH OF THE AREA.

FRIDAY AND FRIDAY NIGHT...THE FRONT DROPS INTO THE FORECAST AREA
WITH TIME. CONVERGENCE ALONG THE FRONT AND SOME RESIDUAL MOISTURE
SHOULD BE ENOUGH FOR SCATTERED SHOWER AND THUNDERSTORM ACTIVITY.
USED A BLEND OF THE ETA AND THE GFS. THE FRONTAL BOUNDARY POSITION
DIFFERENCE IS ABOUT 100 MILES...WITH THE GFS FURTHER NORTH INTO OUR
AREA...WHILE THE ETA HAS THE FRONT PUSHING THROUGH NORTHERN INDIANA
AT 12Z SAT.

.LONG TERM...
THE FRONTAL BOUNDARY WILL CONTINUE TO SINK SSE SATURDAY AND WE WILL
STILL HAVE A CHC OF SHOWERS ACROSS OUR SOUTHERN CWA THROUGH SATURDAY
AFTERNOON. THE FCST FOR THE REMAINDER OF THE WEEKEND IS VERY TRICKY
SINCE THERE CONTINUE TO BE FAIRLY LARGE DISCREPANCIES IN MEDIUM
RANGE GUIDANCE IN HOW FAR SOUTH THE BOUNDARY WILL MAKE IT. FOR NOW
WE WILL STICK WITH A DRY FCST FROM SATURDAY NIGHT THROUGH SUNDAY
SINCE THE MAJORITY OF GUIDANCE AND TRENDS IMPLY THAT THE BOUNDARY
WILL IN FACT SINK SOUTH OF OUR AREA IN A WEAK NE FLOW REGIME AND
WITH WEAK SFC RIDGING IN PLACE.

BEYOND THAT FOR EARLY NEXT WEEK SOME MEDIUM RANGE GUIDANCE TRENDS
ARE BEGINNING TO SUGGEST THAT A COMBINATION OF A WEAK SFC LOW ALONG
WITH AN UPPER LOW OVER THE UPPER MIDWEST COULD BRING SHOWERS EARLY
TO MIDWEEK. WE VERY STRONGLY CONSIDERED ADDING POPS FOR RAIN FOR
THAT TIME FRAME GIVEN OVERALL GUIDANCE TRENDS. HOWEVER AT THIS POINT
TO PRESERVE CONTINUITY WITH OUR PREVIOUS EXTENDED RANGE FCST AND
AFTER COLLAB WITH SURROUNDING OFFICES WE WILL KEEP THE FCST DRY FOR
NOW. HOWEVER FUTURE SHIFTS MAY NEED TO STRONGLY CONSIDER ADDING POPS
EARLY TO MIDWEEK... EVEN THE ECMWF NOW APPEARS TO BE SUGGESTING AN
UPPER LOW COULD DRIFT IN FROM THE WNW IN THAT TIME FRAME.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...NONE.

&&

DUKE

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1215 PM EDT WED SEP 6 2006

LMZ844>849-MIZ037>040-043>046-050>052-056>059-064>067-071>074-071015-
ST JOSEPH TO SOUTH HAVEN-SOUTH HAVEN TO HOLLAND-
HOLLAND TO GRAND HAVEN-GRAND HAVEN TO WHITEHALL-
WHITEHALL TO PENTWATER-PENTWATER TO MANISTEE-MASON-LAKE-OSCEOLA-
CLARE-OCEANA-NEWAYGO-MECOSTA-ISABELLA-MUSKEGON-MONTCALM-GRATIOT-
OTTAWA-KENT-IONIA-CLINTON-ALLEGAN-BARRY-EATON-INGHAM-VAN BUREN-
KALAMAZOO-CALHOUN-JACKSON-
1215 PM EDT WED SEP 6 2006

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

.DAY ONE...TODAY AND TONIGHT

A FEW THUNDERSTORMS ARE POSSIBLE THIS AFTERNOON AND EARLY EVENING
ACROSS SOUTHWEST MICHIGAN. THE PROBABILITY OF STORMS IS QUITE SMALL.
SEVERE THUNDERSTORMS ARE NOT EXPECTED. BRIEF HEAVY RAIN...CLOUD TO
GROUND LIGHTNING STRIKES AND PEA SIZE HAIL WOULD BE THE MAIN
THREATS. A FEW OF THE STRONGER STORMS COULD PRODUCE HAIL UP TOWARD
ONE HALF TO THREE QUARTERS OF AN INCH.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

WAVES ON LAKE MICHIGAN WILL BUILD TO 3 TO 5 FEET ON THURSDAY NIGHT
AS WINDS INCREASE OUT OF THE SOUTHWEST. THE NEXT CHANCE OF
THUNDERSTORMS WILL BE FRIDAY AFTERNOON AND NIGHT AS A COLD FRONT
DROPS SOUTH FROM CANADA.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED.

MEADE DUKE