Hail and Damaging Winds in Michigan, July 20, 2003

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
750 AM EST SUN JUL 20 2003

UPDATED PUBLIC DISCUSSION...

WITH INITIAL WAVE PAST AND ONLY FEW CLOUDS OVER AREA EARLY THIS
MORNING...UPDATED GRIDS TO ACCOUNT FOR SUNSHINE THIS MORNING AND
PUSHED THUNDER CHANCES BACK TO LATE MORNING FAR NORTH AND MID TO
LATE AFTERNOON SOUTH. LOW LEVEL MOISTURE HAVING TROUBLE MAKING ITS
WAY BACK INTO AREA. MODEL INSTABILITY OVERDONE THIS MORNING DUE TO
LACK OF LOW LEVEL MOISTURE. AS SOUTHWEST FLOW INCREASES TODAY AHEAD
OF NEXT SHORT WAVE AND COLD FRONT...EXPECT THE LOW LEVEL MOISTURE TO
ADVECT BACK IN AND INSTABILITY TO INCREASE THIS AFTERNOON. THUS KEPT
THE HIGHER POPS IN THE NORTH AND CHANCE POPS SOUTH. REMAINDER OF
GRIDS UNCHANGED.

LASHLEY

AVIATION DISCUSSION FOR 12Z TAFS...
CLUSTER OF STORMS BEING WATCHED AT 6Z TAF ISSUANCE HAS WEAKENED AND
CONTINUE TO MOVE SE INTO MICHIGAN. AS A RESULT...ONLY SOME THINNING
MID CLOUDS WILL AFFECT THE TAF SITES THROUGH EARLY AFTERNOON.
QUESTION STILL REMAINS IF CONVECTION WILL POP UP THIS AFTERNOON
BEFORE THE MAIN SHOW TONIGHT. KEEPING VICINITY THUNDER IN FOR A FEW
HOURS THEN BRIEFLY END PRECIP. WILL CARRY PREDOMINATE THUNDER AFTER
3Z AT KSBN(4Z KFWA) FOR A FEW HOURS AS SHORT WAVE ENERGY BRINGS IN A
DECENT SQUALL LINE. WILL LIKELY BE GUSTY WINDS...BUT HELD OFF ON TAF
MENTION FOR NOW. AFTERWARDS...WENT WITH JUST SHOWERS THROUGH THE
REMAINDER OF THE TAF PERIOD TO COVER ANYTHING LINGERING BEHIND THE
LINE.

TODAY-TUESDAY...
WEAK SHORT WAVE COMBINING WITH LOW LEVEL WARM ADVECTION TO PRODUCE
SCT SHOWERS OVER THE CWA AT 07Z. THESE SHOULD MOVE OUT OF THE AREA
AROUND DAYBREAK. ANOTHER SHORT WAVE MOVG INTO NW WI EXPECTED TO MOVE
SE ACROSS THE CWA 15-18Z. INSTABILITY/MOISTURE WILL BE INCREASING
THIS MORNING SO GREATER COVERAGE/QPF WITH NEXT WAVE. BY LATE AFTN
AIRMASS FORECAST TO BECOME VERY UNSTABLE. MAIN FORCING MECHANISM
WILL JUST BE CONTINUED LOW LEVEL WARM/MOIST ADVECTION. STORMS
EXPECTED TO BE SCATTERED AND SOME POSSIBLY SVR GIVEN BUFKIT SOUNDING
FORECASTS OF SHEAR/INSTABILITY.  BETTER CHC OF SEVERE EXPECTED
TONIGHT AS A LOW PRESSURE DEEPENS AS IT MOVES EAST ACROSS THE GREAT
LAKES AND SENDS A STRONG COLD FRONT INTO THE CWA. MODERATE
INSTABILITY EXPECTED AHEAD OF THE FRONT ALONG WITH STRONG DEEP LAYER
SHEAR AND FORCING SHOULD ALLOW FOR SOME SEVERE STORMS TO DEVELOP.
HAVE CONTINUED WITH MENTION OF SEVERE STORMS FOR TONIGHT. PRECIP
WATER FORECAST 1.5-2 INCHES SO SOME HEAVY DOWNPOURS LIKELY...THOUGH
THINK FRONT WILL MOVE THROUGH QUICKLY ENOUGH SO THAT FLOODING
PROBLEMS WILL BE MINOR.

FRONT SHOULD MOVE THROUGH SERN PORTION OF CWA EARLY MONDAY. SOME
INSTABILITY SHOWERS MAY DEVELOP BEHIND THE FRONT LATER IN THE DAY AS
COLD AIR ALOFT AND A WEAK SHORT WAVE APPROACHES THE AREA. THIS LOW
CHC OF SHOWERS CONTINUES MONDAY NIGHT AS THE SHORT WAVE MOVES
THROUGH THE CWA. ALSO CONTINUED WITH A CHC OF SHOWERS TUESDAY AS
THERMAL TROUGH FORECAST BY GFS TO MOVE INTO THE AREA RESULTING IN
UNSTABLE CONDITIONS DURING THE DAY. JT

EXTENDED DISCUSSION...TUES NIGHT THROUGH SATURDAY
NOT OVERLY IMPRESSED WITH PRECIP CHCS FOR TUES NGT INTO WEDS. LOOKS
LIKE MAIN UPPER TROUGH WILL BEGIN SHIFTING EAST OF THE AREA...MAINLY
ON WEDS. BEING THAT FAR OUT AND TROUGH STILL IN THE GENERAL
AREA...WILL KEEP LOW CHC POPS. RIDGE MOVES IN FOR THURS AND
FRI...WITH RETURN FLOW SETTING UP FOR SAT AHEAD OF ANOTHER WEAK
SYSTEM. CONTINUED DRY FOR THURS AND FRI WITH CHC SHOWERS/STORMS INTO
SATURDAY. LF

.IWX...
IN...NONE.
MI...NONE.
OH...NONE.

INZ003>009-012>018-020-022>027-032>034-MIZ077>081-OHZ001-002-004-005-
015-016-024-025-210915-

HAZARDOUS WEATHER OUTLOOK...CORRECTED SPELLING
NATIONAL WEATHER SERVICE NORTHERN INDIANA
421 AM EST SUN JUL 20 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHERN INDIANA...NORTHWEST
OHIO AND SOUTHWEST LOWER MICHIGAN.

.DAY ONE...TODAY AND TONIGHT

THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND
TONIGHT ACROSS NORTHERN INDIANA... AND A SLIGHT RISK OVER SOUTHERN
MICHIGAN AND NORTHWEST OHIO. A COLD FRONT WILL MOVE INTO THE AREA
FROM THE WEST TONIGHT. SCATTERED THUNDERSTORMS ARE EXPECTED AHEAD OF
THE FRONT TODAY. SOME OF THESE STORMS MAY BE SEVERE THIS AFTERNOON
WITH LARGE HAIL AND DAMAGING WINDS.  AS THE STRENGTHENING COLD FRONT
APPROACHES OUR AREA TONIGHT...THUNDERSTORMS ARE EXPECTED TO FORM
INTO A LINE MOVING SOUTHEAST ACROSS THE AREA.  SEVERE STORMS ARE
AGAIN POSSIBLE. DAMAGING WINDS ARE THE MAIN THREAT TONIGHT. FORECAST WIND
PROFILES INDICATE THAT ISOLATED TORNADOES ARE ALSO POSSIBLE.  HEAVY
RAIN WILL LIKELY ACCOMPANY THE STORMS...HOWEVER...MOVEMENT OF THE
THUNDERSTORMS IS EXPECTED TO BE SUFFICIENT TO AVOID EXCESSIVE
RAINFALL.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SUNDAY
A LINE OF THUNDERSTORMS AHEAD OF THE COLD FRONT WILL LIKELY BE
ONGOING MONDAY MORNING ACROSS NORTHWEST OHIO AND SOUTHERN PORTIONS
OF NORTHEAST INDIANA.  SOME OF THESE STORMS MAY BE SEVERE WITH
DAMAGING WINDS POSSIBLE SOUTHEAST OF A LINE FROM HUNTINGTON INDIANA
TO ARCHBOLD OHIO.

ANOTHER COLD FRONT WILL MOVE THROUGH THE AREA SATURDAY...POSSIBLY
CAUSING THUNDERSTORMS AGAIN.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS LIKELY EITHER THIS AFTERNOON OR TONIGHT OR
BOTH.

STAY TUNED TO NOAA WEATHER RADIO FOR FURTHER DETAILS OR UPDATES, OR
CHECK OUR WEB SITE AT WWW.CRH.NOAA.GOV/IWX

JT