Severe Thunderstorm Warning 55, NWS Detroit, MI

SOUTHEAST MICHIGAN AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
300 PM EDT MON JUL 22 2002

CAPES IN THE 4000-5000J/KG RANGE APPEAR TO HAVE PEAKED ACROSS THE
CENTRAL PORTION OF THE CWA AND HAVE PUNCHED DOWN TO THE 3500J/KG
RANGE...HIGHER DEW POINTS APPEAR TO HAVE MIXED OUT AS WELL...WITH DEW
POINTS IN THE LOWER 70S CWA WIDE. BEST CONVERGENCE HAS ALSO SHIFTED
TO THE SOUTH AND EASTERN PORTIONS OF THE CWA. WATER VAPOR IMAGE
SHOWS A NARROW DRY SLOT OVER SOUTHERN LAKE MICHIGAN WHICH SHOULD
ROTATE INTO SOUTHEAST LOWER AROUND 6 PM...THIS MAY PRODUCE A BRIEF
INCREASE IN THE CONVECTION...THUS WITH CAPES STILL FAIRLY IMPRESSIVE
...A FEW OUTFLOW BOUNDARIES LEFT BEHIND AND PRE FRONTAL TROF MOVING
INTO THE CWA...ANTICIPATE WATCH TO CONTINUE TO EXPIRATION.
ANTICIPATE SKIES TO CLEAR FAIRLY QUICKLY OVERNIGHT...CLOUDS
ASSOCIATED WITH SECONDARY TROF AXIS OVER THE WESTERN UPPER WILL
STRUGGLE TO REACH SOUTHEAST LOWER AS TROF WEAKENS AND LOSS OF DIURNAL
COMPONENT.

MODELS IN GOOD AGREEMENT THROUGH 60 HOURS...PREFER THE SLIGHTLY
COOLER AVN SOLUTION BASED ON UPSTREAM TEMPERATURES AND DEW POINTS.

MODELS INDICATE 850 MB THETA-E RIDGE AXIS AND RIGHT REAR QUADRANT OF
UPPER JET TO SLIP SOUTH AND EAST OF THE CWA BY 00Z. PRECIPITATION
HAS ALSO DWINDLED ALONG THE COLD FRONT WHICH IS NOW PARALLEL TO THE
MID LEVEL FLOW...AND SHOWING VERY LITTLE LOW LEVEL CONVERGENCE. THUS
ANTICIPATE SHOWER THREAT TO END CWA WIDE BY MIDNIGHT.

HIGH PRESSURE AND ASSOCIATED COOL AND DRY NORTH TO NORTHEAST FLOW TO
AFFECT THE REGION FROM LATE TONIGHT THROUGH THURSDAY MORNING. WARM
AIR ADVECTION AND A COUPLE OF WEAK UPPER WAVES ON THURSDAY MAY BE
ENOUGH TO TRIGGER SOME SCATTERED CONVECTION...DEEPER MOISTURE ACROSS
FAR NORTHERN PORTION OF CWA...THUS WILL GRADUATE POPS FROM NORTH TO
SOUTH.

.DTX...NONE.

GSS

MIZ047>049-053>055-060>063-068>070-075-076-082-083-222300-

HAZARDOUS WEATHER OUTLOOK FOR SOUTHEAST MICHIGAN
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
133 PM EDT MON JUL 22 2002

...SEVERE THUNDERSTORM WATCH NUMBER 520 IN EFFECT UNTIL 700 PM FOR
SOUTHEAST MICHIGAN...

DISPATCHERS...PLEASE NOTIFY YOUR EMERGENCY MANAGERS IMMEDIATELY.

HAZARDS...

A SEVERE THUNDERSTORM WATCH IS IN EFFECT UNTIL 7 PM EDT FOR THE
FOLLOWING
COUNTIES...BAY...MIDLAND...SANILAC...SAGINAW...LAPEER...GENESEE...
SHIAWASSEE...MACOMB...OAKLAND...LIVINGSTON...WASHTENAW...LENAWEE...
HURON...TUSCOLA...ST. CLAIR...WAYNE AND MONROE.
THIS INCLUDES THE CITIES OF BAY
CITY...MIDLAND...SANDUSKY...SAGINAW...LAPEER...FLINT...OWOSSO...
WARREN...PONTIAC...HOWELL...ANN ARBOR...ADRIAN...CARO...PORT
HURON...DETROIT AND MONROE.

NUMEROUS THUNDERSTORMS WILL CONTINUE THIS AFTERNOON AND EVENING.
SOME OF THESE STORMS WILL PRODUCE WIND GUSTS UP TO 70 MPH...HAIL UP
TO THREE QUARTERS OF AN INCH IN DIAMETER AND VERY HEAVY RAINFALL.

DISCUSSION...
A STRONG COLD FRONT WILL MOVE ACROSS SOUTHEAST MICHIGAN LATE THIS
AFTERNOON THROUGH THIS EVENING. THUNDERSTORMS ARE STILL EXPECTED TO
DEVELOP AHEAD OF THIS COLD FRONT EARLY THIS AFTERNOON. DUE TO THE
UNSTABLE AIRMASS ALREADY IN PLACE ACROSS SOUTHEAST MICHIGAN...STORMS
WILL HAVE THE POTENTIAL OF DEVELOPING ANYWHERE IN SOUTHEAST MICHIGAN
EARLY THIS AFTERNOON. THE THREAT OF THUNDERSTORMS AND SEVERE WEATHER
WILL END WITH THE PASSAGE OF THE COLD FRONT. THE FRONT SHOULD PASS
THROUGH THE TRI CITIES AROUND 4 PM. FLINT AND THE THUMB SHOULD SEE
THE PASSAGE OF THE FRONT AROUND 6 PM...WHILE THE DETROIT METRO ARE
WILL SEE THE PASSAGE OF THE FRONT AROUND 8 PM. MOVEMENT OF
THUNDERSTORMS IS EXPECTED TO BE NORTHEAST AT 30 MPH.

SPOTTER ACTIVATION...
SPOTTERS HAVE ALREADY BEEN ACTIVATED.

OUTLOOK FOR TUESDAY AND WEDNESDAY...
NO HAZARDOUS WEATHER IS EXPECTED TUESDAY OR WEDNESDAY.

STAY TUNED TO NOAA WEATHER RADIO... OR LOCAL MEDIA OUTLETS... FOR
THE LATEST FORECAST INFORMATION FROM THE NATIONAL WEATHER SERVICE.
YOU CAN ALSO OBTAIN THE LATEST FORECAST ON THE NATIONAL WEATHER
SERVICE WEB SITE.

HTTP://WWW.CRH.NOAA.GOV/DTX/ (ALL LOWER CASE)

CONSIDINE