Severe Thunderstorm Warning 64, NWS Northern Indiana

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
126 PM EST THU MAY 18 2000

FCST DILEMMA ARE POPS/TEMPS AND SVR/HEAVY RAIN THREAT THIS EVENING.

17Z SFC MAP SHOWING TRIPLE POINT LOW NR KCNC AND WARM FRONT SNAKING
EWD ALG A KOXV...KDVN...KVPZ...KDTX LINE. DEEPENING COLD POOL IN
ASSOC/W DVLPG CONVECTIVE CLUSTER OVR N IL/IN PUSHING BNDRY SWD THRU
N IL/IN ATTM. ADDITIONAL STORMS DVLPG INVOF TRIPLE POINT LOW SWD ALG
TRAILING COLD FRONT THRU NE MO. PROFILER/VWP ALL SHOWING STG LOW
LVL JET IN PLACE ACRS WARM SECTOR COINDICENT WITH APPROACHING MID
LVL SPEED MAX AND SHORTWAVE TROF IN MO.

12Z MODELS IN DECENT AGREEMENT WITH LG SCALE FTRS. ETA INITIALIZED
SFC LOW IN IA BETTER AND ITS 6HR QPF PICKS UP DVLPG CONV BEST.
MAIN PROBS THIS AFTERNOON/EVENING ARE CONT SVR THREAT AND GROWING
POTENTIAL FOR HEAVY RAIN. 12Z RAOBS/VIS IMAGERY CONT TO INDICATE
MAJORITY OF WARM SECTOR REMAINS CAPPED. WITH LOW LVL JET PROGGED TO
CONT BACKING AHD OF LOW AND TREMENDOUS LG SCALE ASCENT/CVRG ON NOSE
OF JET AND HIGH PWATS...SVR THREAT TO CONT INTO THIS EVENING
WITH FLOODING A BIGGER CONCERN OVERNIGHT. THIS IS SIMILAR TO WHAT HAS
OCCURRED OVR THE KGRR FA. ETA/NGM QPFS PRETTY GENEROUS WITH 1.5-2.0
INCHES PROGGED.

LOW CONTS TO FILL OVERNIGHT WITH 850MB CONV BNDRY PARKED OVR N HALF
OF CWA WHICH WILL CONT RAIN INTO TOMORROW AM. OTHERWISE CAA ON
BACKSIDE OF SYS AND CLDS WILL KEEP DIURNAL TEMP RISE AT A MINIMUM.
CONT CYCLONIC FLOW FRI NIGHT WILL KEEP CLDS IN UNTIL RIDGE AXIS
WORKS IN SAT AND THINGS FINALLY DRY OUT.

WILL WAIT UNTIL ISSUANCE TIME BEFORE MAKING DECISION ON NEED FOR FFA.

.IWX...TOR WATCH FOR IND COUNTIES UNTIL 21Z...SEVERE WATCH 5UNTIL 00Z
FOR REMAINDER OF FA.

TEH

INZ003>009-012>018-020-022>027-032>034-MIZ077>081-OHZ001-002-004-005-
015-016-024-025-190100-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE NORTHERN INDIANA
1017 AM EST THU MAY 18 2000

...SEVERE THUNDERSTORMS ARE EXPECTED TO DEVELOP ACROSS THE AREA THIS
AFTERNOON...

A STRONG LOW PRESSURE SYSTEM WAS LOCATED OVER SOUTHERN IOWA THIS
MORNING WITH A WARM FRONT EXTENDING EASTWARD INTO EXTREME NORTHERN
INDIANA AND A SIGNIFICANT UPPER LEVEL JET STREAK COMING OUT OF
MISSOURI. THIS COMBINED WITH INCREASING DESTABILIZATION AHEAD OF
THIS SYSTEM WILL ALLOW FOR RAPID THUNDERSTORM DEVELOPMENT BY EARLY
AFTERNOON. PRIMARY THREATS WILL BE LARGE HAIL NORTH OF THE WARM
FRONT AND DAMAGING WINDS AND ISOLATED TORNADOES ALONG AND SOUTH OF
THE WARM FRONT. THE ENTIRE AREA IS AT RISK FOR SEVERE THUNDERSTORMS
THIS AFTERNOON WITH THE GREATEST RISK FOR ISOLATED TORNADOES ALONG
AND SOUTH OF A KNOX TO DEFIANCE LINE. CURRENT INDICATIONS POINT TO
RAPID THUNDERSTORM DEVELOPMENT OVER NORTHWEST INDIANA BETWEEN 1100 AM
AND 100 PM.

SKYWARN SPOTTER ACTIVATION WILL BE NEEDED THIS AFTERNOON.

STAY TUNED TO NOAA WEATHER RADIO...LOCAL RADIO OR TELEVISION OR
CABLE TELEVISION FOR THE LATEST ON THIS DEVELOPING SEVERE WEATHER
THREAT.

TEH