Severe Thunderstorm Warning 45, NWS Detroit, MI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
300 PM EDT THU JUN 1 2000

SHORT RANGE MODELS IN GENERAL AGREEMENT. SURFACE WARM FRONT HOVERING
OVER NORTHERN PART OF SOUTHEAST MI SHOULD PUNCH NORTHEAST OVERNIGHT
AS UPPER MS VALLEY STRENGTHENING LOW MOVES TO NEAR OR JUST NORTH OF
LAKE HURON BY 12Z FRIDAY. UNSEASONABLY STRONG COOL ADVECTION IN WAKE
OF ASSOCIATED COLD FRONT FRIDAY....BEFORE HIGH PRESSURE BUILDS IN
FROM THE WEST FRIDAY NIGHT AND SATURDAY. IN THE MID LEVELS...
WEAKENING LOBE OF VORTICITY PROGGED TO PASS ON THROUGH SOUTHEASTERN
LOWER MI OVERNIGHT INTO EARLY FRIDAY...THEN BRISK DRY NORTHWEST
FLOW. THE BIG QUESTION IS OUTCOME OF ANTICIPATED CONVECTION VICINITY
OF WARM FRONT...AND IN WARM SECTOR AHEAD OF COLD FRONT OVERNIGHT.
DYNAMICS WISE...MODEL TIME SECTIONS DEPICT BEST DEEP LIFT LATE
AFTERNOON AND THIS EVENING...OTHERWISE MAINLY WEAK SUBSIDENCE
THROUGH 48 HOURS. ALSO 850 TO 500 MB QVECTOR CONVERGENCE MODEST
OVERNIGHT...WITH DEPICTED 850/500 MB DIFFERENTIAL PVA AND LOW LEVEL
WARM ADVECTION BOTH PRETTY DECENT. GOOD 1000 TO 850 MB
FRONTOGENETICAL FORCING ALSO KICKS IN MAINLY AFTER MIDNIGHT...AND
SURFACE CONVERGENCE GENERALLY WEAK WITH THE COLD FRONT. SHARP
INCREASE IN 925 TO 850 MB WIND SPEEDS LATE AFTERNOON INTO THIS
EVENING OF NOTE AS WELL...TO WORK WITH SURFACE BASED CAPES AS HIGH
AS 2500 JOULES AND LIFTED INDICES TO ABOUT MINUS 7 LATE THIS
AFTERNOON/EVENING. ALSO...SOMEWHAT FAVORABLE 250 MB DIVERGENCE
OVERNIGHT. SO...MODEST DYNAMICS TO WORK WITH GOOD INSTABILITY
TONIGHT...AWAITING CONVECTION TO POP. SOME UNCERTAINTY
AS TO HOW MUCH CONVECTION WILL POP IN WARM SECTOR WITH FOCUSING BOUNDARIES
HARD TO FIND UNTIL COLD FRONT NEARS. RELATIVE HUMIDITY TIME SECTIONS SHOW
LOW AND OCCASIONAL MID MOISTURE TONIGHT...THEN LINGERING LOW
MOISTURE FRIDAY UNTIL EVEN THAT DROPS OFF FRIDAY NIGHT AS PER ALL
MODELS. OVERALL DRY MID AND UPPER LEVELS DRY OUT EVEN MORE FRIDAY
AND FRIDAY NIGHT...CONTINUING SATURDAY.

WILL BLEND FWC AND FAN TEMPERATURES. GOING CLOSER TO FAN
TEMPERATURES ESPECIALLY BEHIND COLD FRONT...GIVEN COOLNESS OF AIR
MASS AND DRYNESS OF AIR.

FOR THE EXTENDED PERIODS...MODELS POINT TO THIS BEING A BASICALLY
DRY PERIOD. MRF SHOWS A FAIRLY VIGOROUS MID LEVEL SHORTWAVE TROUGH
MOVING INTO SOUTHERN LAKES REGION BY MONDAY...WITH UKMET AND ECMWF
PRETTY MUCH SHOWING THIS TOO...AS DOES THE CANADIAN MODEL. HAVING
MOVED THROUGH...THE MODELS THEN SHOW CONSIDERABLE VARIANCE...WITH
MRF CLOSING OFF THIS SYSTEM OVER TENNESSEE VALLEY...WHEREAS OTHER 3
ABOVE MENTIONED DO NOT. AT THE SURFACE...MRF FARTHER NORTH WITH
SURFACE LOW PASSING SOUTH OF LAKES THAN UKMET OR ECMWF AND FASTER BY
ABOUT 12 HOURS THAN CANADIAN. LOCAL EXTENDED ETA SHOWS SURFACE LOW
MOVING ACROSS KY MONDAY...SLOWER AND A LITTLE FARTHER SOUTH THAN MRF
WITH RAINFALL MAINLY STAYING SOUTH OF MI. NOT TOO TRUSTING OF MRF
DETAILS...GIVEN ITS GREAT OSCILLATION OF THIS SYSTEM PAST FEW RUNS.
STILL...MRF/CANADIAN MOISTURE AND LIFT FIELDS WOULD SUPPORT MENTION
OF SHOWERS FOR MONDAY...SO WILL SO INCLUDE CHANCE SHOWER MENTION FOR
MONDAY...IN LIGHT OF MODEL UNCERTAINTIES...WITH BEST CHANCE IN THE
SOUTH.

.DTX...NONE.

DWD

MIZ047>049-053>055-060>063-068>070-075-076-082-083-021200-

SEVERE WEATHER OUTLOOK FOR SOUTHEAST LOWER MICHIGAN
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
845 PM EDT THU JUN 1 2000

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

DISPATCHERS...PLEASE NOTIFY YOUR EMERGENCY MANAGERS IMMEDIATELY.

...SEVERE THUNDERSTORM WATCH 403 IN EFFECT UNTIL 2 AM FOR MIDLAND...
BAY...SAGINAW...SHIAWASSEE...GENESEE...LIVINGSTON AND WASHTENAW.

A LINE OF THUNDERSTORMS FROM NORTHWESTERN LOWER MICHIGAN SOUTHWEST
ACROSS LAKE MICHIGAN...WILL BE MOVING SOUTHEAST AT 45 MPH INTO THE
WATCH AREA OF SOUTHEAST LOWER MICHIGAN STARTING AFTER 9 PM AND
CONTINUING THROUGH 2 AM.

SOME STORMS COULD PRODUCE WINDS IN EXCESS OF 58 MPH AND HAIL GREATER
THEN THREE QUARTERS OF AN INCH.

THE REST OF SOUTHEAST LOWER MICHIGAN IS STILL UNDER A THREAT FOR
SEVERE WEATHER OVERNIGHT.  A WATCH MAY BE NEEDED LATER AS THE
THUNDERSTORM@ ACTIVITY MOVES THROUGH THESE AREAS BETWEEN MIDNIGHT AND
4 AM.

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

DRC

MIZ047>049-053>055-060>063-068>070-075-076-082-083-021200-

SEVERE WEATHER OUTLOOK FOR SOUTHEAST LOWER MICHIGAN
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
1110 PM EDT THU JUN 1 2000

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

DISPATCHERS...PLEASE NOTIFY YOUR EMERGENCY MANAGERS IMMEDIATELY.

...SEVERE THUNDERSTORM WATCH 403 IN EFFECT UNTIL 2 AM FOR MIDLAND...
BAY...SAGINAW...SHIAWASSEE...GENESEE...LIVINGSTON AND WASHTENAW.

...SEVERE THUNDERSTORM WATCH 405 IN EFFECT UNTIL 3 AM FOR HURON...
TUSCOLA...SANILAC...LAPEER...OAKLAND...ST CLAIR...MACOMB...WAYNE...
LENAWEE AND MONROE.

AT 1110 PM...A LINE OF THUNDERSTORMS FROM NORTH OF MT PLEASANT TO
AROUND KALAMAZOO WILL MOVE SOUTHEAST AT 50 MPH INTO SOUTHEAST LOWER
MICHIGAN.

SOME STORMS COULD PRODUCE WINDS IN EXCESS OF 58 MPH AND HAIL GREATER
THEN THREE QUARTERS OF AN INCH.

THE MAIN LINE OF POTENTIALLY SEVERE THUNDERSTORMS SHOULD MOVE EAST
OF THE WATCH AREAS BY 3 AM.  OTHER SHOWERS AND THUNDERSTORMS WILL
MOVE THROUGH BEHIND THIS LINE THROUGH SUNRISE...HOWEVER...THOSE
ARE NOT EXPECTED TO BE SEVERE.

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

DRC