Severe Thunderstorm Warning 87, NWS Detroit, MI

SOUTHEAST MICHIGAN AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
440 PM EDT SUN SEP 9 2001

...ZONES ISSUED...

SEVERE THREAT CONTINUES FOR CWA TONIGHT. STRONG DYNAMICS WILL HELP
TO PROMOTE CONTINUED DEVELOPMENT OF THUNDERSTORMS. CONTRIBUTIONS
FROM POTENT DPVA...AND UPPER LEVEL DIVERGENCE WILL FUEL THUNDERSTORM
DEVELOPMENT. SEVERE THREAT WILL BE DEPEND UPON AMOUNT OF INSTABILITY
THAT CAN BE GENERATED. EARLIER TODAY...SEVERE TSRA IN MONROE
COUNTY...OCCURRED WITH 81/77 YIELDING 5800 J/KG OF CAPE.
HOWEVER...CLOUDS/RAIN HAVE PUSHED TEMPERATURES DOWN ACROSS MOST OF
THE CWA INCLUDING 77 AT MONROE. VIS LOOP SHOWS SOME BREAKS
DEVELOPING IN OVC. WINDS HAVE MADE A SUBTLE SHIFT TO THE SOUTH
ACROSS MUCH OF THE CWA...E.G...MBS HAS GONE FROM 120 AT 15Z TO 170
AT 20Z. STILL BEST TORNADIC POTENTIAL EXISTS NORTH AND EAST PORTION
OF THE CWA...PHN STILL AT 150.

MESOETA TIMING PUSHES ALL FORCING EAST OF CWA BY 06Z FOLLOWED BY
SURGE OF DRY AIR. HIGH PRESSURE BUILDS IN FROM THE SOUTH AND WEST
MONDAY THROUGH TUESDAY NIGHT THEN PULLS WEST WEDNESDAY AS NEXT FRONT
APPROACHES CWA. DRY CONDITIONS WITH NEAR TO SLIGHTLY BELOW NORMAL
TEMPERATURES WILL PREVAIL MONDAY THROUGH WEDNESDAY MORNING. AS FRONT
APPROACHES CWA ON WEDNESDAY WILL INTRODUCE CHANCE POPS FOR NORTHERN
THIRD OF CWA.

HIGH BUILDING IN IS OF PACIFIC ORIGIN...SO NOT EXPECTING OVERLY COOL
CONDITIONS. HOWEVER...IT WILL BE DRY...ALLOWING FOR NIGHTLY
RADIATIONAL COOLING TO OCCUR. WILL OPT FOR TEMPERATURES ABOUT IN
LINE WITH A BLEND OF MAV/S AND ETA 2M TEMPERATURES.

WILL MAINTAIN PATCHY FOG FOR MONDAY NIGHT. MOST OF THE CWA RECEIVED
CONSIDERABLE RAINFALL TODAY...AND WILL LIKELY RECEIVE MORE TONIGHT.
DO EXPECT GOOD DRYING TOMORROW...BUT WITH HIGH BUILDING IN AND
RESIDUAL MOISTURE IN BOUNDARY LAYER...WILL LIKELY SEE USUAL FOGGY
LOCALES EXPERIENCE PATCHY FOG.

.DTX...NONE.

OKEEFE

MIZ047>049-053>055-060>063-068>070-075-076-082-083-100200-

SEVERE WEATHER OUTLOOK FOR SOUTHEAST LOWER MICHIGAN
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
305 PM EDT SUN SEP 9 2001

...TORNADO WATCH NUMBER 734 IS IN EFFECT FOR ALL OF SOUTHEAST
MICHIGAN UNTIL 10 PM...

DISPATCHERS...PLEASE NOTIFY YOUR EMERGENCY MANAGERS IMMEDIATELY.

THE NATIONAL WEATHER SERVICE HAS ISSUED TORNADO WATCH 734 FOR ALL OF
SOUTHEAST MICHIGAN.  THIS WATCH IS IN EFFECT UNTIL 10 PM.  SOME
COMMUNITIES IN THE WATCH INCLUDE SAGINAW...MIDLAND...BAY CITY...BAD
AXE...SANDUSKY...FLINT...LAPEER...PORT HURON...PONTIAC...ANN ARBOR...
DETROIT...ADRIAN...AND MONROE.  SPOTTER ACTIVATION IS REQUESTED.

VERY MOIST AIR REMAINS OVER SOUTHEAST MICHIGAN AHEAD OF A COLD
FRONT.  THIS COLD FRONT...LOCATED NEAR THE SHORELINE OF WESTERN
LOWER MICHIGAN LATE IN THE AFTERNOON...WILL SLOWLY MOVE EAST...
SWEEPING THROUGH SOUTHEAST MICHIGAN BY 4 AM.  AS THE COLD FRONT
MOVES EAST...A STRENGTHENING LOW PRESSURE CENTER WILL MOVE NORTH
ALONG THE FRONT THROUGH CENTRAL AND NORTHERN LOWER MICHIGAN...
REACHING NORTHERN LAKE HURON LATE THIS EVENING.  ALL OF THESE WILL
PROVIDE FOR NUMEROUS THUNDERSTORMS.

THE MAIN THREAT FROM THUNDERSTORMS WILL BE DAMAGING WIND GUSTS
TO 80 MPH...HAIL TO AN INCH IN DIAMETER...AND HEAVY RAIN.  RAINFALL
RATES COULD EXCEED AN INCH IN A HOUR...RESULTING IN PONDING OF
WATER.  AS THE SURFACE LOW PRESSURE CENTER MOVES NORTH ACROSS
MICHIGAN...THOUGH...AN ISOLATED THUNDERSTORM COULD BE CAPABLE OF
PRODUCING A TORNADO.  ALL THUNDERSTORMS WILL TEND TO MOVE NORTHEAST
AT 40 MPH.

THE THREAT FOR SEVERE WEATHER SHOULD END BY 10 PM.  HOWEVER...OTHER
SHOWERS AND THUNDERSTORMS LIKELY WILL PERSIST BEYOND 10 PM...ENDING
IN THE TRI CITIES AROUND MIDNIGHT AND TOWARD LAKE HURON AND DETROIT
BY 4 AM.  AFTER 10 PM...THE PRIMARY THREAT FROM THUNDERSTORMS WILL
BE FREQUENT LIGHTNING...SMALL HAIL...AND WIND GUSTS TO 40 MPH.

STAY TUNED TO NOAA WEATHER RADIO...OR YOUR LOCAL RADIO...
TELEVISION...OR CABLE TELEVISION STATION...FOR THE LATEST WEATHER
INFORMATION.

DJF

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
444 PM EDT SUN SEP 9 2001

TIME(EDT)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0128 PM    2 N SAMARIA               MI   .75 INCH HAIL
09/09/01   MONROE                         REPORTED BY THE PUBLIC VIA
                                          LOCAL FIRE DEPARTMENT

0339 PM    MOUNT CLEMENS             MI   76 MPH TSTM WIND GUST
09/09/01   MACOMB                         OBSERVATION FROM KMTC

0405 PM    MARINE CITY               MI   WIND DAMAGE
09/09/01   ST CLAIR                       NUMEROUS TREES BLOWN DOWN
                                          AND TRAVEL TRAILER
                                          OVERTURNED AS REPORTED BY
                                          LAW ENFORCEMENT