Severe Thunderstorm Warning 113, NWS Detroit, MI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
130 PM EDT WED JUN 23 2004

.DISCUSSION...

CONVECTION TRYING TO FIRE AHEAD OF FRONT AND FRONTAL WAVE OVER
SOUTHERN WISCONSIN AND SHOULD DEVELOP OVER WEST CENTRAL LOWER AS
WELL AS CAPES HAVE INCREASED TO AROUND 1000J/KG. WOULD NOT BE
SURPRISED TO SEE CONVECTION FIRE A LITTLE FURTHER SOUTH OVER
NORTHERN ILLINOIS AS WELL AS NOSE OF 850 MB JET WORKS EAST ACROSS
THE NORTHERN OHIO VALLEY. FOCUSING MECHANISM LACKING OVER LOWER
MICHIGAN THIS AFTERNOON...SO ORGANIZED CONVECTION WILL BE HARD TO
GENERATE. LIMITING FACTOR ALSO WILL BE DEGREE OF INSTABILITY...SFC
DEW POINTS IN MID 50S...AND LACK OF GOOD SHEAR AT THE ONSET. BY 00Z
SHEAR SHOULD INCREASE SIGNIFICANTLY AS 850 MB JET APPROACHES
SOUTHERN LOWER MICHIGAN. HAIL ALSO A CONCERN WITH WET BULB ZERO
AROUND 8500 FT. MAIN THREAT FOR STRONG CONVECTION REMAINS FROM PTK
NORTHWARD.

MODELS IN GENERAL AGREEMENT THROUGH 84 HOURS. HOWEVER THE ETA IS
MUCH MORE AGGRESSIVE WITH SURFACE WAVE MOVING ACROSS NORTHERN LOWER
OVERNIGHT. PREFER THE STRONGER ETA SOLUTION AT THIS TIME AS LFQ OF
300 MB JET INTERACTS WITH THIS FEATURE. WATER VAPOR LOOP SHOWS NOSE
OF THIS JET ENTERING INTO SOUTHERN MINNESOTA AND APPROACHING THE
FRONTAL WAVE ALREADY. COMBINATION OF DEEPENING SURFACE WAVE AND
STRENGTHENING 850 MB JET COULD RESULT IN ORGANIZED CONVECTION EARLY
THIS EVENING OVER THE NORTHERN PORTION OF CWA.

MODELS SHOW LEAD COLD FRONT HANGING UP OVER NORTHERN LOWER THIS
EVENING AS SURFACE WAVE DEVELOPS RESULTING IN LACK OF GOOD LOW LEVEL
CONVERGENCE SOUTH OF PTK UNTIL AROUND MIDNIGHT. LEAD 500 MB
VORTICITY LOBE ALSO TRACKING ACROSS MAINLY NORTHERN PORTION OF CWA
LATE THIS EVENING...AND SECOND WAVE AROUND 09Z. THUS GREATER QPF AND
POPS OVER NORTH HALF OF CWA TONIGHT. WILL CONTINUE WITH MENTION OF
TRW THROUGH THE NIGHT AS WELL...WITH FRONTAL BOUNDARY HUNG UP OVER
NORTHERN LOWER PERSISTENT 850 MB THETA-E ADVECTION ACROSS THE CWA
OVERNIGHT AND MID LEVEL LAPSE RATES AROUND 6C.

GOOD SHOT OF 850-500 MB DPVA AS VORT SHEAR AXIS PUSHES THROUGH
NORTHERN CWA AROUND 00Z FRIDAY AND SOUTHERN CWA OVERNIGHT THURSDAY.
THUS WILL CONTINUE WITH CHANCE POPS FOR THURSDAY NIGHT. WILL ALSO
HAVE TO CONTEND WITH COLD UPPER CORE PASSING JUST NORTH OF CWA LATE
THURSDAY AFTERNOON INTO THE EVENING ACROSS THE NORTHERN PORTION OF
THE CWA. 500 MB TEMPERATURES COOL  TO -18C...HOWEVER 850 TEMPS
ALREADY PLUNGING...RESULTING IN VERTICAL TOTALS IN THE LOWER TO MID
20S. WILL MENTION ISOLATED TRW FROM MBS NORTHWARD 21Z THURSDAY
THROUGH 03Z FRIDAY.

FRONT TO FAR SOUTH AND RH FIELDS TO DRY FOR MENTION OF POPS ON
FRIDAY...EVEN WITH WEAK UPPER WAVE MOVING ACROSS THE FAR SOUTH.

PREFER THE COOLER FWC TEMPS FOR TONIGHT AND THE COOLER MET GUIDANCE
TEMPS FOR THURSDAY...GIVEN CLOUD COVER AND MAGNITUDE OF COLD AIR
ADVECTION IN THE AFTERNOON...ESPECIALLY NORTH OF PTK.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...NONE.

&&

GSS

EXPERIMENTAL GRAPHICAL FORECASTS ARE AVAILABLE ONLINE AT
HTTP://WWW.CRH.NOAA.GOV/DTX  (ALL LOWER CASE)

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
500 PM EDT WED JUN 23 2004

MIZ047>049-053-054-241000-
BAY-HURON-MIDLAND-SAGINAW-TUSCOLA-
500 PM EDT WED JUN 23 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR TRI-CITIES AND NORTHERN THUMB
REGION.

.DAY ONE...TONIGHT

THUNDERSTORMS ARE LIKELY THROUGH 4 AM. THERE IS A CHANCE OF ISOLATED
SEVERE THUNDERSTORMS THROUGH MIDNIGHT. THE MAIN HAZARDS WILL BE WIND
GUSTS TO 60 MPH AND HAIL UP TO ONE INCH IN DIAMETER. THUNDERSTORM
MOVEMENT WILL BE EAST AROUND 25 MPH.

A COLD FRONT WILL MOVE FROM NORTHERN LOWER MICHIGAN TO THE SAGINAW
VALLEY TONIGHT. THUNDERSTORMS WILL CONTINUE TO DEVELOP OVER THE
SAGINAW VALLEY AND THUMB REGIONS THROUGH MIDNIGHT. THE THREAT OF
THUNDERSTORMS WILL END WITH THE PASSAGE OF THE COLD FRONT LATE
TONIGHT.

.DAY TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

THERE IS A CHANCE OF ISOLATED THUNDERSTORMS THURSDAY AFTERNOON AND
EVENING.

.SPOTTER INFORMATION STATEMENT...

DISPATCHERS...PLEASE NOTIFY YOUR EMERGENCY MANAGER IMMEDIATELY.
SPOTTER ACTIVATION MAY BE NEEDED THIS EVENING.

MIZ055-060>063-068>070-241000-
GENESEE-LAPEER-LIVINGSTON-MACOMB-OAKLAND-SANILAC-SHIAWASSEE-
ST. CLAIR-
500 PM EDT WED JUN 23 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE I 69 AND M 59 CORRIDORS.

.DAY ONE...TONIGHT

SCATTERED THUNDERSTORMS WILL CONTINUE OVERNIGHT. THERE IS A CHANCE
OF ISOLATED SEVERE THUNDERSTORMS THROUGH MIDNIGHT. THE MAIN HAZARDS
WILL BE WIND GUSTS TO 60 MPH AND HAIL UP TO ONE INCH IN DIAMETER.
THUNDERSTORM MOVEMENT WILL BE EAST AT AROUND 25 MPH.

A COLD FRONT WILL MOVE FROM NORTHERN LOWER MICHIGAN TO THE SAGINAW
VALLEY TONIGHT. THUNDERSTORMS WILL CONTINUE TO DEVELOP OVER THE
SAGINAW VALLEY AND THUMB REGIONS THIS EVENING THEN DROP SOUTH INTO
THE I 69 AND M 59 CORRIDORS OVERNIGHT.

.DAY TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

DISPATCHERS...PLEASE NOTIFY YOUR EMERGENCY MANAGER IMMEDIATELY.
SPOTTER ACTIVATION MAY BE NEEDED THIS EVENING.

MIZ075-076-082-083-241000-
LENAWEE-MONROE-WASHTENAW-WAYNE-
500 PM EDT WED JUN 23 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR LOCATIONS SOUTH OF M-59.

.DAY ONE...TONIGHT

THERE IS A CHANCE OF THUNDERSTORMS TONIGHT. AN ISOLATED STORM COULD
BECOME SEVERE THROUGH MIDNIGHT. THE MAIN HAZARDS WILL BE WIND GUSTS TO
60 MPH AND HAIL UP TO ONE INCH IN DIAMETER. THUNDERSTORM MOVEMENT
WILL BE EAST AROUND 25 MPH.

A COLD FRONT WILL MOVE FROM NORTHERN LOWER MICHIGAN TO THE SAGINAW
VALLEY TONIGHT. SCATTERED THUNDERSTORMS WILL DEVELOP AHEAD OF THIS
FRONT AFTER 8 PM...THE THREAT OF SEVERE WEATHER WILL END AFTER
MIDNIGHT DUE TO THE LOSS OF DAYTIME HEATING.

.DAY TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

THERE IS A CHANCE OF THUNDERSTORMS THURSDAY.

.SPOTTER INFORMATION STATEMENT...

DISPATCHERS...PLEASE NOTIFY YOUR EMERGENCY MANAGER IMMEDIATELY.
SPOTTER ACTIVATION MAY BE NEEDED THIS EVENING.

GSS