Severe Thunderstorm Warning 54, NWS Northern Indiana

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
230 PM EST MON JUN 13 2005

.SHORT TERM...
TONIGHT AND TUESDAY.

FOR THE SHORT TERM...WILL USE A BLEND OF THE RUC40/NAM.

VISIBLE SATELLITE IMAGERY THIS AFTN DEPICTED A LINE OF SHOWERS AND
THUNDERSTORMS LOCATED FROM CNTRL WISCONSIN...SOUTHEAST INTO
NORTHWEST INDIANA.  RUC40 AND SFC ANALYSIS SHOWED THAT THESE SHOWERS
AND THUNDERSTORMS WERE ALONG A SFC TROF.  ALSO...A WEAK S/WV ALOFT
WAS LOCATED ABOVE THE SFC FEATURE.  A MOIST AND UNSTABLE AIRMASS HAS
COMBINED WITH THESE LIFTING MECHANISMS...AND THUS HAVE RESULTED IN
THE SHOWERS AND THUNDERSTORMS.  RUC40 FCSTS THE SFC TROF AND UPR LVL
S/WV TO BE ALONG A SWRN MICHIGAN TO EXTREME NW OHIO AXIS BETWEEN 00Z
AND 03Z.  AT THIS POINT...HAVE PENCILED IN 20 POPS IN THE ENTIRE
CWFA FOR THIS EVENING...BUT WILL MAKE A LAST MINUTE DECISION TO SEE
IF THIS HAS TO BE RAISED.

THE MAIN THUNDERSTORM ACTIVITY WILL COME DURING THE OVERNIGHT HOURS
AS A POTENT UPR LVL LOW CENTERED OVER NE NEBRASKA LIFTS NE INTO SE
MINNESOTA BY 12Z TUESDAY. AS IT DOES...SPOKES OF S/WV ENERGY WILL
ROTATE AROUND IT...SOME OF WHICH WILL PASSES ACRS
ILLINOIS/WISCONSIN.  MEANWHILE...A MODERATELY STRONG MID TO UPR LVL
JET AROUND 90 KTS WILL ACCOMPANY THIS S/WV ENERGY.  THESE WX
ELEMENTS WILL PROVIDE THE UPR DIVERGENCE.  IN THE LOW LVLS...AN
INCREASING LOW LVL JET WILL PROVIDE THE LOW LVL CONVERGENCE.  THE
RESULT OF THE UPR DIV/LOW LVL CONV COUPLET WILL BE AN OUTBREAK OF
SUPERCELLS ACRS WISCONSIN AND ILLINOIS.  AS THESE STORMS MOVE ENE
TOWARD AN AXIS OF INSTABILITY OVER INDIANA...THEY SHOULD CONGEAL
INTO A SQUALL LINE DUE TO A MORE UNIDIRECTIONAL SHEAR PROFILE ACRS
THE FCST AREA.  HENCE...WILL GO WITH LIKELY POPS ACRS THE ENTIRE
FCST AREA FOR THE OVERNIGHT HOURS...AND WILL PLACE SEVERE WX WORDING
IN THE ZONES.  AT THIS TIME...THE PRIMARY SEVERE WX THREAT SHOULD BE
DAMAGING WINDS...BUT SOME LARGE HAIL CAN NOT BE RULED OUT.

THUNDERSTORM ACTIVITY SHOULD WANE IN INTENSITY AND COVERAGE BY DAY
BREAK TUESDAY.  THUS...AM ONLY EXPECTING PERHAPS A SHOWER OR
THUNDERSTORM DURING THE MORNING HOURS (30 POP).  AS THE
AFOREMENTIONED UPR LVL LOW MOVES EAST TOWARD LAKE MICHIGAN...AN
ATTENDANT COLD FRONT WILL MOVE EAST AS WELL.  THE NAM FCSTS THIS
FRONT TO BE NEAR THE INDIANA/ILLINOIS BORDER BY 18Z...AND JUST EAST
OF THE CWFA BY 00Z WEDNESDAY.  AN ASSOCD S/WV WITH THE COLD
FRONT...COMBINED WITH THE FRONT ITSELF...SHOULD PROVIDE ENOUGH
DYNAMICS FOR SOME SHOWERS AND THUNDERSTORMS.  THE HIGHEST CHC WILL
OCCUR ACRS THE EAST WITH THE LEAST IN THE WEST.  WILL LAYER POPS
FROM 50 EAST TO 30 WEST.  SOME SEVERE WX IS ALSO
POSSIBLE...ESPECIALLY OVER THE ERN HALF OF THE CWFA.

AS FOR TEMPS...MET VALUES FOR TONIGHT LOOK GOOD...SO HAVE USED IT.
USED THE NAM THICKNESS VALUES AT 21Z TUESDAY TO COME UP WITH A
TEMPERATURE GRADIENT ACRS THE FCST AREA.  THIS METHOD YIELDS HIGHS
IN THE LOWER 80S WEST TO THE UPPER 80S EAST.

&&

.LONG TERM...
TUESDAY NIGHT INTO MONDAY

VIGOROUS LOW PRESSURE SYSTEM WILL CONTINUE TO SLOWLY MIGRATE WITH A
FEW DISTURBANCES ROTATING AROUND SYSTEM LIKE A PINWHEEL. THIS MAY
PRODUCE ADDITNL SHRA/TSRAS TUE NIGHT AFTR CLD FNT PASSES. THE LAST
OF SHWVS W/ THIS SYS EFFECTING THE CWA WILL BE DIURNALLY DRIVEN ON
WED...REINTRODUCED POPS DURING THE DAY.

MODELS STILL NOT GRASPING THE LONGER RANGE WELL. GFS DEPICTS A 500
MB LOW WAY TO FAR SOUTH AND WEST MID-LATE WEEK. NAM SHOWS TRIPLE
POINT DVLPG BY 84 HRS OVER NEW ENGLD. BOTH GFS/NAM AGREE WITH A JET
MAX PUSHING THROUGH OHIO VALLEY THU NIGHT...BUT NAM IN AGREEMENT
WITH ECMWF ON H50 LOW DVLPG FURTHER TO THE NW OVER SE ONTARIO. I CAN
NOT SEE A CLOSED H50 LOW DVLP FURTHER SW OVER N OH WITH 100+KT JET
MAX MOVG OVER CENTRL OH VLY AT 90HR AS 12Z GFS RUN FCSTS. WITH 85H
AND 70H LOW OVER ALBANY AS GFS DEPICTS...A FURTHER NORTH SOLN MAKES
MORE SENSE. SO WITH THAT IN MIND WILL NOT TREND COOLER LATE WEEK AS
MAV AND MEX/MEN GUIDANCE SUGGESTS.

VERY STRONG RIDGE WILL HOLD AND BUILD OVER THE PLAINS AND INTO S
CTRL CANADA AS TROF DEEPENS OUT IN THE W PAC. WV CURNTLY SHOWS
STRONG UPR JET STARTING TO DIG S-WARD NEAR ALEUTIAN ISLS. THIS
SETUP WILL LEAVE US HIGH AND DRY INTO NEXT WEEK AS RIDGE HOLDS FIRM
OVR CENTRAL CONUS...IGNORED GFS THINKING OF CLOSED LOW FORMING IN SE
US.

&&

.AVIATION...
VISIBLE SATELLITE IMAGERY THIS AFTN WAS SHOWING THAT THE PESKY LOW
CLOUDS OVER THE ERN TWO THIRDS OF THE CWFA WERE FINALLY DEVELOPING
INTO A CUMULUS DECK.  AM EXPECTING BY TAF ISSUANCE THAT KSBN AND
KFWA SHOULD BE ABOVE THE MVFR 3000 FT THRESHOLD.

MEANWHILE...THE LATEST RUC40 DEPICTED A WEAK SFC TROF AXIS FROM SWRN
WISCONSIN INTO NRN ILLINOIS.  THIS FEATURE...COMBINED WITH A WEAK
S/WV ALOFT...WAS CAUSING SOME SHOWERS AND THUNDERSTORMS TO DEVELOP
OVER THAT REGION.  RUC40 SLIDES THIS WEAK TROF AND UPR LVL S/WV NE
INTO WRN INDIANA BY 21Z.  SOME OF THE SHOWERS AND THUNDERSTORMS MAY
MAINTAIN THEMSELVES...SO SATELLITE AND RADAR TRENDS WILL HAVE TO BE
MONITORED.

OTHERWISE...THE MAIN THUNDERSTORM ACTIVITY IS EXPECTED OVERNIGHT AS
S/WV ENERGY ROTATING AROUND AN UPR LOW OVER THE CNTRL PLAINS
INTERACTS WITH A DEVELOPING SFC TO 850 MB LOW LVL JET OVER WISCONSIN
AND NRN/CNTRL ILLINOIS THIS EVENING.  THE RESULT WILL BE SUPERCELLS
ACRS WISCONSIN AND ILLINOIS.  AS THESE STORMS MOVE ENE...THEY WILL
LIKELY CONGEAL INTO A SQUALL LINE AS HODOGRAPHS INDICATE A MORE
UNIDIRECTIONAL SHEAR ENVIRONMENT OVER INDIANA.  HAVE PLACED A TEMPO
TSRA AT THIS POINT AT BOTH KSBN AND KFWA DURING THE OVERNIGHT
HOURS.  THE MAIN SVR WEATHER THREAT FROM THE STORMS WILL BE DAMAGING
WINDS.  HAVE NOT SPECIFICALLY PLACED STRONG WINDS IN THE TAF AT THIS
POINT AS IT IS STILL TOO PREMATURE...BUT LATER FCSTS WILL HAVE TO
HONE IN ON POTENTIAL SQUALL LINE AND ITS ASSOCD WIND DAMAGE THREAT.

THEREAFTER...FCST AREA SHOULD FIND ITSELF IN A LULL BETWEEN 12Z AND
18Z.  A COLD FRONT WILL REACH THE ILLINOIS/INDIANA BORDER AROUND 18Z
TUESDAY...AND WILL THEN MOVE ACRS THE CWFA THROUGH 00Z WEDNESDAY.
THIS FRONT...COMBINED WITH DAY TIME HEATING...WILL CAUSE SCATTERED
THUNDERSTORMS TO DEVELOP ALONG AND AHEAD OF IT AFTER 18Z.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
.IN...NONE.
.MI...NONE.
.OH...NONE.
.LK MI...NONE.

&&

SHORT TERM...HICKMAN
LONG TERM...WAMSLEY

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE NORTHERN INDIANA
846 AM EST MON JUN 13 2005

INZ003>009-012>018-020-022>027-032>034-MIZ077>081-OHZ001-002-004-005-
015-016-024-025-141344-
ADAMS IN-ALLEN OH-ALLEN IN-BERRIEN MI-BLACKFORD IN-BRANCH MI-CASS MI-
CASS IN-DE KALB IN-DEFIANCE OH-ELKHART IN-FULTON OH-FULTON IN-
GRANT IN-HENRY OH-HILLSDALE MI-HUNTINGTON IN-JAY IN-KOSCIUSKO IN-
LA PORTE IN-LAGRANGE IN-MARSHALL IN-MIAMI IN-NOBLE IN-PAULDING OH-
PULASKI IN-PUTNAM OH-ST. JOSEPH MI-ST. JOSEPH IN-STARKE IN-
STEUBEN IN-VAN WERT OH-WABASH IN-WELLS IN-WHITE IN-WHITLEY IN-
WILLIAMS OH-
INCLUDING THE CITIES OF...ANGOLA...ARCHBOLD...AUBURN...
BENTON HARBOR...BENTON HEIGHTS...BERNE...BLUFFTON...BREMEN...BRYAN...
BUCHANAN...BUTLER...COLDWATER...COLUMBIA CITY...DECATUR...DEFIANCE...
DELPHOS...DOWAGIAC...DUNKIRK...DUNLAP...ELKHART...FAIR PLAIN...
FAIRMOUNT...FORT SHAWNEE...FORT WAYNE...GARRETT...GAS CITY...
GEORGETOWN...GOSHEN...GRANGER...GRISSOM AFB...GULIVOIRE PARK...
HARTFORD CITY...HICKSVILLE...HILLSDALE...HUNTINGTON...KENDALLVILLE...
KNOX...LA PORTE...LAGRANGE...LIGONIER...LIMA...LOGANSPORT...MARION...
MICHIGAN CITY...MISHAWAKA...MONTICELLO...MONTPELIER...NAPOLEON...
NAPPANEE...NEW HAVEN...NILES...NORTH MANCHESTER...OSSIAN...OTTAWA...
PERU...PLYMOUTH...PORTLAND...ROCHESTER...SIMONTON LAKE...
SOUTH BEND...ST. JOSEPH...STURGIS...SWANTON...SYRACUSE...
THREE RIVERS...TRAIL CREEK...TRI-LAKES...UPLAND...VAN WERT...
WABASH...WARSAW...WAUSEON...WESTVILLE...WINAMAC AND WINONA LAKE
846 AM EST MON JUN 13 2005

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

.DAY ONE...TODAY AND TONIGHT

THUNDERSTORMS WILL DEVELOP TOWARDS EVENING OVER WESTERN PORTIONS OF
THE REGION AHEAD OF A LOW PRESSURE SYSTEM DEVELOPING IN THE MIDWEST.
THUNDERSTORMS WILL CONTINUE TO DEVELOP OVERNIGHT WITH LARGE HAIL AND
DAMAGING WINDS BEING THE MAIN THREATS. AN ISOLATED TORNADO WILL ALSO
BE POSSIBLE.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

STRONG LOW PRESSURE SYSTEM WILL MOVE FURTHER EASTWARD ON TUESDAY. ITS
ASSOCIATED COLD FRONT WILL TRIGGER THUNDERSTORMS FROM LATE MORNING
INTO THE AFTERNOON. WIDESPREAD SEVERE WEATHER IS POSSIBLE WITH
DAMAGING WINDS AND LARGE HAIL THE MAIN THREATS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE REQUIRED TONIGHT AND TUESDAY.

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

LMZ043-046-061-141344-
846 AM EST MON JUN 13 2005

THIS HAZARDOUS WEATHER OUTLOOK IS FOR EXTREME SOUTHEAST LAKE
MICHIGAN.

.DAY ONE...TODAY AND TONIGHT

THUNDERSTORMS WILL DEVELOP TOWARDS EVENING OVER WESTERN PORTIONS OF
THE REGION AHEAD OF A LOW PRESSURE SYSTEM DEVELOPING IN THE MIDWEST.
THUNDERSTORMS WILL CONTINUE TO DEVELOP OVERNIGHT WITH LARGE HAIL AND
DAMAGING WINDS BEING THE MAIN THREATS. AN ISOLATED TORNADO WILL ALSO
BE POSSIBLE.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

STRONG LOW PRESSURE SYSTEM WILL MOVE FURTHER EASTWARD ON TUESDAY. ITS
ASSOCIATED COLD FRONT WILL TRIGGER THUNDERSTORMS FROM LATE MORNING
INTO THE AFTERNOON. WIDESPREAD SEVERE WEATHER IS POSSIBLE WITH
DAMAGING WINDS AND LARGE HAIL THE MAIN THREATS.

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

WAMSLEY