Lightning Strike in Michigan, May 9, 2002

SOUTHEAST MICHIGAN AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
340 AM EDT THU MAY 9 2002

...SHOWERS AND THUNDERSTORMS FOLLOWED BY STRONG GRADIENT WINDS...

LOOKING BACK...MARINE INFLUENCE WAS A BIT STRONGER COMPARED TO THE
NCEP MODELS FORECAST (HENCE THE MAX TEMPS YESTERDAY ABOUT 1-2
CATEGORIES LOWER ACROSS THE CWA).  THE LOCALLY PRODUCE HI-RES WSETA
DID A VERY GOOD JOB WITH THE DEPICTION OF WARM FRONT (FURTHER SOUTH)
WITH A MUCH LONGER EAST WIND FLOW THAN THOSE FORECAST BY THE NCEP
MODELS.  IN FACT...WE ARE CURRENTLY LOOKING AT THE WARM FRONT
APPROACHING THE MICHIGAN BORDER BUT HALTING AS MARINE LAYER IS QUITE
DEEP (SFC-900MB).  THIS WILL BE OUR FIRST ISSUE TO BE QUICKLY
FOLLOWED BY THUDERSTORMS AND POTENTIALLY STRONG GRADIENT WINDS THIS
AFTERNOON.

H2O VAPOR LOOP NICELY SHOWS POTENT UPPER LOW OVER THE NORTHERN
PLAINS WITH DEEP MOISTURE RETURN HEADING NORTHEAST THRU THE
MISSISSIPPI RIVER VALLEY.  STRONG LLJ COMBINING WITH 100+ KTS
250/300MB AND POWERFUL COLD FRONT ALL COMBINING FOR CONVECTION (NOT
OVERLY ORGANIZED) ACROSS THE CENTER OF THE CONUS.
THEREAFTER...FROPA AROUND 18Z WITH QUICK ISALLOBARIC RISES AND
SUBSIDENCE/CAA TO BE FOLLOWED BY SFC AND MID LEVEL RIDGING FOR THE
END OF THE WEEK.  IT LOOKS LIKE WE WILL HAVE THE POTENTIAL FOR A
REPEAT PERFORMANCE THIS WEEKEND.

TODAY...
AT THE MOMENT WE FIND IT HARD TO GET SEVERE THUNDERSTORMS INTO THE
CWA.  FIRST WE HAVE TO ERODE THE STABLE MARINE LAYER ACROSS THE CWA
WHICH HAS PROVEN TO BE QUITE A FEAT.  THIS POINTS TO ELEVATED
ACTIVITY WITH BUFKIT SOUNDINGS FROM THE ETA (AND NEW AVN) SHOW
ELEVATED CAPES BETWEEN 500 AND 1000 J/KG AND SWI/S NEAR 0 (-1 TO -4C
PER AVN).  TRIPLE POINT AXIS IS FORECAST TO OCCUR NEAR CHICAGO AND
BE SOUTH OF THE CWA THRU THIS AFTERNOON WHICH REDUCES THE THREAT FOR
SFC BASED CONVECTION TO OCCUR.  SO WE WILL CONTINUE WITH THE
CATEGORICAL WORDING FOR SHOWERS AND THUNDERSTORMS THROUGH THIS
MORNING WEST AND EARLY AFTERNOON EAST.  SOME HEAVY RAINFALL IS
POSSIBLE WITH PWAT/S NEAR 1.50.  THEN WE TURN OUR ATTENTION TO
WINDS AFTER FROPA.  MIXING LAYER HEIGHTS BASED ON SFC MAX FORECAST
TEMPS WOULD BRING WIND GUSTS TO 40 KTS (OVER 45 MPH) WITH 6-HR
ISALLOBARIC PRES RISES PER AVN/ETA OF NEAR 8 MBS.  AS SAID IN THE
PREVIOUS AFD...THIS IS MUCH LESS THAN THE MARCH 9TH EVENT.  WE WILL
COORDINATE WITH OTHER OFFICES THIS MORNING... AND WE ARE LEANING
TOWARD HOLDING BACK WIND ADVISORY FOR THE CWA.

TONIGHT THRU FRIDAY...
WINDS WILL SUBSIDE A BIT OVERNIGHT (DECOUPLING?) WITH MOCLEAR SKIES
SOUTH AND PTCLOUDY NORTH.  SOME WRAP AROUND MOISTURE UNDER THE COLD
UPR LOW MAY BRING SOME AC TO THE NORTH.  OTHERWISE WITH 850 TEMPS
BELOW ZERO AND EQUALLY IMPRESSIVE 500MB TEMPS -23C COMBINING WITH A
GREAT DEAL OF SUNSHINE FRIDAY...TEMPS SHOULD REMAIN BELOW CLIMO.
MOS NUMBERS LOOK A BIT HIGH AND WILL DROP A FEW.

FRIDAY NIGHT AND SATURDAY...
PACIFIC JET BRINGS ANOTHER LOW ASHORE WITH LEE SIDE CYCLOGENESIS FOR
THE WESTERN HIGH PLAINS.  THIS WILL BRING ABOUT MOISTURE RETURN THRU
THE MISSISSIPPI RIVER VALLEY WITH OVERRUNNING RAIN/EMBEDDED
THUNDERSTORMS BY 12Z SATURDAY.  AVN AND 84 HR ETA ARE IN GOOD
AGREEMENT WITH MCS ACTIVITY TO CROSS OVER THE CWA DURING THE
AFTERNOON ON SATURDAY.

A BIT CONCERNED ABOUT THE POTENTIAL FOR SOME FLOODING ACROSS THE
SOUTHERN CWA SATURDAY NIGHT INTO SUNDAY.  PER THE AVN/GEM WE HAVE A
PROLONGED SOUTH FLOW WITH PWATS GETTING NEAR 1.75 PER THE AVN
SOLUTION.  WITH UPPER TROF STILL WEST OF THE REGION AND WAVES
HEADING NORTHEAST ALONG THE FRONT...TRAINING ECHOS IS A CONCERN.
DAY CREW WILL OVERLOOK THE SITUATION WITH NEW GUIDANCE.

THANX FOR THE COORD GRR...APX AND CLE  WE WILL HOLD OFF ON
HEADLINES BUT ISSUE AN HWO (SPS).

.DTX...GALE WARNING ALL OF LAKE HURON THIS AFTERNOON THRU TONIGHT.

BGM

MIZ047>049-053>055-060>063-068>070-075-076-082-083-092015-

HAZARDOUS WEATHER OUTLOOK FOR SOUTHEAST MICHIGAN
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
521 AM EDT THU MAY 9 2002

...SEVERE WEATHER POTENTIAL STATEMENT FOR SOUTHEAST MICHIGAN...

DISPATCHERS...PLEASE NOTIFY YOUR EMERGENCY MANAGERS IMMEDIATELY.

THREAT...
THUNDERSTORMS WILL AFFECT ALL OF SOUTHEAST LOWER MICHIGAN THIS
MORNING THROUGH EARLY AFTERNOON.  SOME THUNDERSTORMS MAY CONTAIN
GUSTY WINDS AND HEAVY RAIN BEFORE EXITING THE REGION WEST TO
EAST BETWEEN 1 PM AND 4 PM.  THEN STRONG WEST WINDS OF 20 TO 30 MPH
WITH GUSTS TO 40 MPH WILL OCCUR BEHIND THE DEPARTING THUNDERSTORMS.

DISCUSSION...
A WARM FRONT JUST SOUTH OF THE MICHIGAN STATE BORDER WILL SLOWLY
MOVE NORTHWARD THIS MORNING.  A FEW SHOWERS AND THUNDERSTORMS ARE
EXPECTED ALONG AND AHEAD OF THE WARM FRONT BUT NOT EXPECTED TO BECOME
SEVERE.  HOWEVER...A STRONG COLD FRONT OVER LAKE MICHIGAN EARLY THIS
MORNING WILL MOVE EAST ACROSS THE STATE AND EXIT THE REGION BY MID
AFTERNOON. THUNDERSTORMS ALONG AND AHEAD OF THIS COLD FRONT MAY BRING
WIND GUSTS TO NEAR 45 MPH ACCOMPANIED BY HEAVY RAINFALL. RAINFALL
AMOUNTS OF NEAR ONE HALF OF ONE INCH IS POSSIBLE. THUNDERSTORMS WILL
MOVE NORTHEAST BETWEEN 35 AND 40 MPH.

BEHIND THE DEPARTING COLD FRONT...STRONG WEST WINDS WILL DEVELOP.
SUSTAINED WIND SPEEDS OF 20 TO 30 MPH WITH GUSTS TO 40 MPH ARE
EXPECTED ACROSS ALL OF SOUTHEAST LOWER MICHIGAN.  THESE HIGH WINDS
WILL CONTINUE THROUGH THE EVENING HOURS BEFORE SLOWLY SUBSIDING
OVERNIGHT.

SPOTTER ACTIVATION...
SPOTTER ACTIVATION IS NOT ANTICIPATED TODAY.

OUTLOOK FOR FRIDAY AND SATURDAY...
NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

STAY TUNED TO NOAA WEATHER RADIO...OR LOCAL MEDIA OUTLETS...FOR
THE LATEST FORECAST INFORMATION. YOU CAN ALSO OBTAIN THE LATEST
FORECAST ONLINE AT:

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

BGM