Severe Thunderstorm Warning 83, NWS Detroit, MI

SOUTHEAST MICHIGAN AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
400 PM EDT SAT SEP 8 2001

FEW HOURS OF SUNSHINE THIS AFTERNOON HAS RESULTED IN LIS IN THE -7
RANGE OVER THE WESTERN AND NORTHERN PORTION OF THE CWA THIS
AFTERNOON...CAPES ARE ALSO CLIMBING TO NEAR 3000 J/KG. WATER VAPOR
LOOP SHOWS MID LEVEL DRYING TAKING PLACE OVER THE WESTERN CWA AS
WELL...THUS WHAT WE LACK IN MID LEVEL WINDS WILL BE ENHANCED BY
NEGATIVE BUOYANCY POTENTIAL AS DRY SLOT WORKS OVER THE REGION. IN
ADDITION MODELS INDICATE A WEAK UPPER WAVE TO BUSH ACROSS THE
NORTHERN PORTION OF THE CWA BETWEEN 18 AND 00Z...ALTHOUGH THIS WAVE
IS VERY HARD TO DISCERN ON SATELLITE LOOPS.

MODELS IN GOOD AGREEMENT THROUGH 60 HOURS...WITH FROPA EARLY MONDAY
MORNING. IN THE MEANTIME BROAD THERMAL AND THETA-E RIDGE AXIS TO
REMAIN OVER THE REGION. A WEAK WAVE WILL BRUSH THE WESTERN AND
NORTHERN PORTION OF THE CWA EARLY THIS EVENING...THEN A STRONG
SURFACE WAVE AND RIGHT REAR QUAD OF 300 MB JET TO DRIVE NORTHEAST
THROUGH THE CWA SUNDAY AFTERNOON. ALTHOUGH WE HAVE BETTER DYNAMICS
ON SUNDAY AFTERNOON SURFACE HEATING WILL BE CUT DOWN AS FRONTAL
CLOUD SHIELD MOVES CLOSER TO THE CWA...KEEPING CAPES AOB 1000 J/KG.
THUS ANOTHER MARGINAL CASE FOR SEVERE THUNDERSTORMS AGAIN SUNDAY
AFTERNOON...

MODELS SHOWING BETTER LOW LEVEL CONVERGENCE ALONG THE FRONT THIS
RUN...HOWEVER CONVERGENCE STILL WEAKENS AS FRONT MOVES INTO
SOUTHEAST LOWER AFTER MIDNIGHT SUNDAY...AND THEN SWEEPS EAST OF THE
STATE IN RESPONSE TO STRONG UPPER WAVE...THUS WILL USE LIKELY POPS
AT THIS TIME. MODELS TRYING TO HOLD ON TO A LITTLE INSTABILITY OVER
THE FAR SOUTHEAST PORTION OF THE CWA AROUND 12Z...THUS WILL STILL
MENTION A RUMBLE POSSIBLE THROUGH APPROXIMATELY 15Z IN MONROE/WAYNE
AREAS.

MAV TEMPERATURES GENERALLY LOOK GOOD. GUIDANCE IS NOT PICKING UP ON
FOG POTENTIAL FOR TUESDAY MORNING THROUGH AS WINDS DECREASE...AND
COLDER CONDENSES OUT AMPLY BOUNDARY LAYER MOISTURE...THUS WILL
MENTION PATCHY FOG WORDING IN ZONES.

 .DTX...NONE.

GSS

MIZ047>049-053>055-060>063-068>070-075-076-082-083-090100-

SEVERE WEATHER OUTLOOK FOR SOUTHEAST LOWER MICHIGAN
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
301 PM EDT SAT SEP 8 2001

...SEVERE THUNDERSTORM WATCH 728 IS IN EFFECT UNTIL 900 PM EDT...

DISPATCHERS...PLEASE NOTIFY YOUR EMERGENCY MANAGERS IMMEDIATELY.

THE NATIONAL WEATHER SERVICE HAS ISSUED SEVERE THUNDERSTORM WATCH
728 FOR MIDLAND...BAY...TUSCOLA...HURON...SAGINAW...SHIAWASSEE...
GENESEE...LIVINGSTON...WASHTENAW...AND LENAWEE COUNTIES UNTIL 900
PM EDT. THIS INCLUDES THE FOLLOWING COMMUNITIES...MIDLAND...BAY
CITY...CARO...BAD AXE...SAGINAW...OWOSSO...FLINT...HOWELL...ANN
ARBOR...AND ADRIAN. A SEVERE THUNDERSTORM WATCH MEANS THAT
CONDITIONS ARE FAVORABLE FOR WINDS OF 58 MPH AND HAIL OF DIME SIZE
OR LARGER.

SPOTTER ACTIVATION HAS TAKEN PLACE.

A MOIST HUMID AIR MASS WILL REMAIN IN PLACE ACROSS SOUTHEAST
MICHIGAN TODAY AND TONIGHT. THIS ENVIRONMENT WILL BE CONDUCIVE TO
THE DEVELOPMENT OF SEVERE THUNDERSTORMS. AS TEMPERATURES WARM THIS
AFTERNOON...SEVERE STORMS ARE POSSIBLE IN AND NEAR THE WATCH
AREA.

SCATTERED SEVERE THUNDERSTORMS ARE POSSIBLE IN THE WATCH AREA OF
SOUTHEAST MICHIGAN...WITH THE MOST LIKELY TIME FOR SEVERE
THUNDERSTORMS BETWEEN 3 PM AND 9 PM LATE THIS AFTERNOON AND EVENING.
THE MAIN THREAT FROM THESE STORMS WILL BE WIND GUSTS TO 60 MPH AND
DIME SIZE HAIL. THE STORMS WILL MOVE NORTHEAST AT 25 MPH. RAINFALL
COULD BE HEAVY WITHIN THESE THUNDERSTORMS...WITH RAINFALL RATES
APPROACHING ONE INCH PER HOUR.

OUTSIDE THE WATCH AREA...ISOLATED SEVERE THUNDERSTORMS ARE POSSIBLE
TONIGHT. TIMING AND THREAT OF THESE STORMS WILL BE THE SAME AS FOR
THOSE IN THE WATCH AREA.

STAY TUNED TO NOAA WEATHER RADIO...OR YOUR FAVORITE MEDIA OUTLET...
FOR THE LATEST WEATHER INFORMATION.

OKEEFE