Severe Thunderstorm Warning 38, NWS Detroit, MI

SOUTHEAST MICHIGAN AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
130 PM EDT TUE JUN 25 2002

CU FIELD BUILDING OVER THE SOUTH HALF OF THE CWA THIS AFTERNOON IN
RESPONSE TO MOISTURE SURGE FROM THE OHIO VALLEY. MODELS DIPICT THIS
NICELY ON 850 MB THETA-E FIELDS...WHICH SHOW FAIRLY STRONG ADVECTION
THIS AFTERNOON AND EVENING...ESPECIALLY ACROSS THE SOUTH AND EASTERN
PORTIONS OF THE CWA. BUFKIT SOUNDINGS STILL SHOW A FAIRLY STRONG CAP
THOUGH AT 12K FEET...WITH SOME EROSION OF THE CAP THIS
EVENING...CAPES ALSO SURGING INTO THE 3000J/KG RANGE ON LATEST LAPS
ANALYSIS...AND PRECIPITABLE WATER ON THE INCREASE AS DEEPER MOISTURE
MOVES INTO THE CWA...THUS IT APPEARS AS THOUGH SCATTERED CONVECTION
WILL DEVELOP OVER THE CWA THIS EVENING...WITH RELATIVELY SLOW
MOVEMENT AND POTENTIAL FOR SOME LOCALLY HEAVY RAIN. ANEMIC SHEAR
PROFILE AND HIGH FREEZING LEVELS SHOULD PRECLUDE ANY SEVERE.

MODELS IN GENERAL AGREEMENT THROUGH 60 HOURS...HOWEVER THE AVN IS A
LITTLE QUICKER WITH FRONTAL PASSAGE WEDNESDAY NIGHT AND THURSDAY
MORNING. PREFER THE QUICKER AVN SOLUTION AS THE ETA MODEL TREND IS
ALSO SLIGHTLY FASTER THIS RUN. FIRST CONCERN IS CONVECTION
OVERNIGHT. MODELS SHOW WEAK UPPER WAVE CURRENTLY OVER THE WESTERN
OHIO VALLEY SLOWLY PUSHING NORTHEAST INTO THE CWA OVERNIGHT...THIS
SHOULD PROVIDE THE FOCUS FOR SCATTERED CONVECTION THROUGH MOST OF
THE NIGHT...WITH AN EMPHASIS ACROSS THE SOUTHERN PORTION OF THE CWA.
MCS INITIATION OVER MINNESOTA LAST NIGHT AND EARLY THIS MORNING WAS
NOT REAL IMPRESSIVE AND FELL APART FAIRLY QUICKLY THIS
MORNING...REMAINING SHOWERS AND CLOUD COVER CURRENTLY MOVING ACROSS
NORTHERN WISCONSIN...AND MAY BRUSH NORTHERN PART OF THE CWA THIS
EVENING. 850 MB JET WEAKER TONIGHT ACROSS THIS REGION...THICKNESS
DIFLUENCE FIELD MUCH WEAKER...AND CORFIDI VECTORS NIL...THUS
INDICATING ANEMIC LOW LEVEL JET...THUS BELIEVE MCS POTENTIAL TONIGHT
WILL BE MINIMAL...AND RESULTING CLOUD COVER ON WEDNESDAY WILL BE
LESS THAN WHAT THE ETA IS INDICATING. WITH MORE SUNSHINE AND LESS
CLOUD FROM MCS DEBRIS IT APPEARS AS THOUGH CAPES IN THE
2000-3000J/KG RANGE ARE MUCH MORE REALISTIC ON WEDNESDAY. ANTICIPATE
BEST ORGANIZED CONVECTION OVER THE NORTHERN PORTION OF THE CWA
WEDNESDAY AFTERNOON IN BETTER CONVERGENCE JUST AHEAD OF THE COLD
FRONT AND IN WEAK UPPER DIFLUENCE IN ASSOCIATION WITH RIGHT REAR
QUADRANT OF 300 MB JET. BETTER CHANCE FOR CONVECTION DROPS SOUTH
DURING THE EVENING. SOUNDING PROFILES UNIDIRECTIONAL AND SHOWING
WEAK SPEED SHEAR...THUS ANY SEVERE POTENTIAL APPEARS TO BE MARGINAL
LATE WEDNESDAY AFTERNOON AND EVENING.

AVN STABILIZES AIRMASS QUICKLY WEDNESDAY NIGHT ACROSS THE NORTHERN
PORTION OF THE CWA...KILLING ANY CONVECTIVE THREAT THERE. HOWEVER
RATHER BROAD SURFACE TROF AND SECONDARY UPPER WAVE WILL REQUIRE
MENTION OF SHOWERS THROUGH THE EARLY MORNING HOURS. AVN/ETA VERY
AGGRESSIVE IN DRYING OUT MID LEVELS ON THURSDAY ACROSS THE ENTIRE
CWA...THIS KILLING ANY CONVECTIVE POTENTIAL...AVN EVEN MORE SO.

PREFER THE WARMER NGM AND AVN GUIDANCE TEMPERATURES ON WEDNESDAY DUE
TO ANTICIPATION OF LESS CLOUD COVER.

.DTX...NONE.

GSS

MIZ047>049-053>055-060>063-068>070-075-076-082-083-260900-

HAZARDOUS WEATHER OUTLOOK FOR SOUTHEAST MICHIGAN
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
215 PM EDT TUE JUN 25 2002

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

DISPATCHERS...PLEASE NOTIFY YOUR EMERGENCY MANAGERS IMMEDIATELY.

HAZARD...
SCATTERED THUNDERSTORMS ARE EXPECTED SOUTH OF INTERSTATE 69 THIS
AFTERNOON...AND ACROSS ALL OF SOUTHEAST LOWER MICHIGAN TONIGHT.
WHILE THESE STORMS ARE NOT EXPECTED TO BECOME SEVERE...THEY MAY
PRODUCE HEAVY RAINFALL AND LOCALIZED FLOODING. WIND GUSTS TO 30 MPH
ARE ALSO POSSIBLE. STORMS THAT DEVELOP WILL MOVE EAST AT 15 MPH.

DISCUSSION...
MOISTURE WILL CONTINUE TO INCREASE ACROSS SOUTHEAST LOWER MICHIGAN
THIS AFTERNOON...LEADING TO ADDITIONAL THUNDERSTORM DEVELOPMENT
INTO THE EVENING HOURS. A COLD FRONT OVER NORTHERN WISCONSIN WILL
MOVE INTO LOWER MICHIGAN ON WEDNESDAY. ADDITIONAL THUNDERSTORMS MAY
DEVELOP AHEAD OF THIS FRONT...MAINLY AFTER MIDNIGHT ACROSS SOUTHEAST
LOWER MICHIGAN.

SPOTTER ACTIVATION...
SPOTTER ACTIVATION IS NOT ANTICIPATED.

OUTLOOK FOR WEDNESDAY AND THURSDAY...
THERE IS A SLIGHT CHANCE OF SEVERE WEATHER ON 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)

BRAVENDER