029  
FXUS63 KIND 191036  
AFDIND  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE INDIANAPOLIS IN  
636 AM EDT SUN MAY 19 2019  
   
UPDATE
 
 
THE AVIATION SECTION HAS BEEN UPDATED BELOW.  
 

 
   
SYNOPSIS
 
 
ISSUED AT 354 AM EDT SUN MAY 19 2019  
 
SHOWERS AND THUNDERSTORMS WILL IMPACT CENTRAL INDIANA THROUGH THIS  
EVENING WITH THE POSSIBILITY OF SEVERE WEATHER THIS AFTERNOON AND  
EVENING AHEAD OF A COLD FRONT. THE FRONT WILL SWING THROUGH THE  
REGION LATE THIS EVENING WITH COOLER AND DRIER CONDITIONS TO START  
THE NEW WEEK AS HIGH PRESSURE TRACKS THROUGH THE GREAT LAKES. MUCH  
WARMER WEATHER RETURNS BY MIDWEEK AND WILL CONTINUE INTO THE HOLIDAY  
WEEKEND ALONG WITH PERIODIC THREATS FOR SHOWERS AND THUNDERSTORMS AS  
A FRONTAL BOUNDARY MEANDERS ACROSS THE OHIO VALLEY.  
 

 
   
NEAR TERM /TODAY THROUGH THIS EVENING/
 
 
ISSUED AT 354 AM EDT SUN MAY 19 2019  
 
CLOUDS WERE INCREASING OVER CENTRAL INDIANA EARLY THIS MORNING WITH  
AREAS OF SHOWERS LIFTING NORTHEAST INTO THE WABASH VALLEY. WINDS  
WERE BECOMING GUSTY OVER ILLINOIS AS WELL WITH AN EXPANDING LOW  
LEVEL JET APPROACHING FROM THE WEST. 07Z TEMPERATURES RANGED FROM  
THE UPPER 60S TO THE MID 70S.  
 
THE APPROACH OF A COLD FRONT LATER TODAY WILL BRING THE THREAT FOR  
RAIN AND THUNDERSTORMS ACROSS THE FORECAST AREA THROUGHOUT THE DAY  
WITH AN INCREASING THREAT FOR SEVERE WEATHER FOCUSED THIS AFTERNOON  
INTO THE EARLY EVENING. IN ADDITION...WINDY CONDITIONS ARE EXPECTED  
ALL DAY WITH NON-THUNDERSTORM WIND GUSTS PEAKING AROUND OR JUST  
ABOVE 40 MPH IN SPOTS.  
 
THE AFOREMENTIONED LOW LEVEL JET WILL ADVECT DEEPER MOISTURE INTO  
THE REGION OVER THE NEXT SEVERAL HOURS...WITH SHOWERS AND PERHAPS A  
FEW THUNDERSTORMS INCREASING IN COVERAGE AS THE MORNING PROGRESSES.  
WHILE VARIATIONS IN CONVECTIVE EVOLUTION EXISTS THROUGHOUT THE CAMS  
AND OTHER MODEL GUIDANCE...FEEL AN INCREASINGLY LIKELY SCENARIO IS  
TWO PRIMARY PERIODS OF CONVECTION IMPACTING CENTRAL INDIANA. THE  
FIRST WILL BE LATER THIS MORNING INTO THE EARLY AFTERNOON AS THE  
PLUME OF DEEPEST MOISTURE MOVES ACROSS THE AREA. PRECIP WATER VALUES  
ARE LIKELY TO PEAK AT 1.50 TO 1.75 INCHES WITH THE LOW LEVEL JET  
PROVIDING AMPLE LIFT TO MAINTAIN REGENERATE CONVECTION INTO THE  
EARLY AFTERNOON. THE PRESENCE OF INCREASING LEVELS OF BL SHEAR AND  
HELICITY DO SUPPORT STRONGER STORMS FROM THIS FIRST BATCH OF  
CONVECTION...ESPECIALLY BY MIDDAY AS HEATING INCREASE. THAT BEING  
SAID...LAPSE RATES AND INSTABILITY LEVELS ARE NOT OVERLY IMPRESSIVE  
THROUGH 18Z AND WHILE ANY ELEVATED CORE MAY TAP INTO THE LOW LEVEL  
JET AND PULL STRONGER WINDS TO THE SURFACE...EXPECT MUCH OF THE  
STORMS THROUGH EARLY AFTERNOON REMAIN SUBSEVERE WITH PERHAPS AN  
UPTICK IN INTENSITY AS THE LINE MOVES INTO A MORE FAVORABLE  
ENVIRONMENT OVER EASTERN COUNTIES IN THE 18-21Z PERIOD BEFORE MOVING  
OFF TO THE EAST.  
 
ONCE THE FIRST BATCH OF CONVECTION SHIFTS EAST WITH THE DEEPER  
MOISTURE PLUME AND LOW LEVEL JET CORE HOWEVER...NUMEROUS SIGNS POINT  
TO A MORE CONDUCIVE ATMOSPHERE FOR SEVERE CONVECTION WITHIN A WINDOW  
ENCOMPASSING LATE AFTERNOON INTO THE EARLY EVENING ALONG AND  
IMMEDIATELY AHEAD OF THE COLD FRONT. BOUNDARY LAYER FLOW WHILE NOT  
AS STRONG AS EARLIER IN THE DAY REMAINS SUPPORTIVE FOR RENEWED  
CONVECTIVE DEVELOPMENT. DIFFLUENCE ALOFT WILL ENHANCE WITH THE  
ARRIVAL OF THE NEGATIVELY TILTED UPPER TROUGH AND A WEAK UPPER  
JETLET WILL BE IN AN IDEAL LOCATION TO ENHANCE CONVECTIVE  
REDEVELOPMENT. OF NOTED INTEREST IS THE HINT OF A SMALL WAVE  
DEVELOPING ALONG THE FRONT BY EARLY EVENING WHICH COULD CONCEIVABLY  
PRODUCE A SHORT PERIOD WITH BACKED BOUNDARY LAYER FLOW AND  
CONSEQUENTLY AN AXIS OF STRONGER BL SHEAR AND HELICITY IMMEDIATELY  
AHEAD OF THE FRONT. THE LACK OF DEEPER MOISTURE BY LATE AFTERNOON  
MAY BE A MITIGATING FACTOR AT LEAST FROM A COVERAGE STANDPOINT BUT  
CAPES LEVELS TO 1000 J/KG OR GREATER WOULD LIKELY BE ENOUGH  
INSTABILITY TO GENERATE A BROKEN LINE OF CONVECTION AHEAD OF THE  
FRONT...SOMETHING BEING SUGGESTED BY SEVERAL OF THE CAMS.  
 
WHILE THE SETUP IS NOT NEARLY AS CLEAN AS DESIRED...THE PRIMARY  
SEVERE WEATHER THREAT WILL LIKELY RESIDE WITHIN THIS 4-6 HOUR  
WINDOW FROM MID AFTERNOON INTO THE EARLY EVENING AS THE INITIAL  
BATCH OF CONVECTION SHIFTS EAST FOLLOWED BY THE BROKEN LINE OF  
CONVECTION AHEAD OF THE FRONTAL BOUNDARY. WHILE DAMAGING WIND  
GUSTS REMAIN THE PRIMARY THREAT CONSIDERING THE STRONGER FLOW IN  
THE UPPER LEVELS OF THE BOUNDARY LAYER...LARGE HAIL AND A FEW  
TORNADOES REMAIN A POSSIBILITY CONSIDERING THE INCREASE IN  
DIRECTIONAL SHEAR SETTING UP JUST AHEAD OF THE COLD FRONT.  
 
TEMPS...CLOUDS AND CONVECTION THROUGH THE MORNING WILL SLOW TEMP  
RISES BUT POTENTIAL FOR SOME SUN PRIOR TO THE CONVECTION WITH THE  
COLD FRONT LATER TODAY SHOULD ENABLE MUCH OF THE AREA TO WARM INTO  
THE MID AND UPPER 70S. UTILIZED A MODEL BLEND WHICH WAS SUPPORTED BY  
LOW LEVEL THERMALS.  
 

 
   
SHORT TERM /OVERNIGHT TONIGHT THROUGH TUESDAY NIGHT/
 
 
ISSUED AT 354 AM EDT SUN MAY 19 2019  
 
FORECAST CHALLENGES FOCUS ON TEMPERATURES THROUGH THE SHORT TERM AND  
RETURNING PRECIP CHANCES BY TUESDAY NIGHT.  
 
ANY LINGERING CONVECTION WILL DEPART THE EASTERN COUNTIES AROUND OR  
SHORTLY AFTER 06Z TONIGHT AS THE COLD FRONT SWEEPS EAST OF THE  
REGION. DESPITE A COOLER...DRIER AIRMASS EXPANDING INTO THE FORECAST  
AREA OVERNIGHT...MODEL SOUNDINGS SHOW A SHALLOW BUT STOUT INVERSION  
DEVELOPING AND PERSISTING THE REST OF THE NIGHT AND POTENTIALLY  
THROUGH MOST OF MONDAY MORNING. WILL KEEP CLOUD COVERAGE UP A BIT  
THROUGH DAYBREAK MONDAY WITH SKIES BECOMING PARTLY CLOUDY DURING THE  
DAY AS PROGRESSIVELY DRIER AIR SUBSIDES INTO THE BOUNDARY LAYER.  
WITH COLD ADVECTION IN THE WAKE OF THE FRONT FOR MONDAY...LIKELY TO  
BE SOME REDEVELOPMENT OF DIURNAL CU AS WELL...ESPECIALLY FOCUSED  
ACROSS THE NORTHERN HALF OF THE FORECAST AREA.  
 
HIGH PRESSURE WILL EXPAND ACROSS THE REGION MONDAY INTO TUESDAY WITH  
DRY AND COOLER WEATHER AS WINDS CARRY A NORTHERLY COMPONENT THROUGH  
MONDAY NIGHT. AN INCREASINGLY AMPLIFIED FLOW REGIME WILL DEVELOP  
ALOFT THROUGH THE SHORT TERM AS AN IMPRESSIVE UPPER LOW KICKS OUT OF  
THE SOUTHERN ROCKIES MONDAY NIGHT THEN ROTATES INTO THE HIGH PLAINS  
BY TUESDAY NIGHT. A RAPIDLY DEEPENING SURFACE WAVE WILL ACCOMPANY  
THE UPPER LOW FROM THE TEXAS PANHANDLE NORTH INTO WESTERN NEBRASKA  
RESULTING IN A MULTI-DAY WIDESPREAD SEVERE WEATHER THREAT ACROSS THE  
SOUTHERN AND CENTRAL PLAINS EXPANDING EAST INTO THE OZARKS AND  
MISSOURI VALLEY. DOWNSTREAM RIDGING WILL ONCE AGAIN STRENGTHEN  
ACROSS THE MISSISSIPPI AND OHIO VALLEYS BY TUESDAY BEFORE SHIFTING  
EAST BY EARLY WEDNESDAY.  
 
ANY LINGERING CU FROM MONDAY AFTERNOON WILL DIMINISH MONDAY EVENING  
WITH MAINLY CLEAR SKIES DEVELOPING. CLEARING WILL BE SHORT LIVED AS  
MID AND HIGH LEVEL CLOUDS ASSOCIATED WITH CONVECTION ACROSS THE  
PLAINS SPREADS EAST INTO THE REGION EARLY TUESDAY BEFORE LIFTING  
NORTH LATER IN THE DAY. A DRY EASTERLY FLOW WILL PERSIST IN THE  
BOUNDARY LAYER FOR MUCH OF TUESDAY BEFORE VEERING TUESDAY NIGHT.  
DEEPER MOISTURE AND LIFT WILL EXPAND INTO THE OHIO VALLEY AHEAD OF  
AN OCCLUDED BOUNDARY WITH NUMEROUS SHOWERS AND THUNDERSTORMS  
ARRIVING LATE TUESDAY NIGHT.  
 
TEMPS...EXPECT COOLER TEMPERATURES THROUGH MUCH OF THE SHORT TERM  
BEFORE WARMTH RETURNS MIDWEEK. TRENDED TOWARDS THE COOLER MET  
GUIDANCE FOR HIGHS MONDAY WITH COLD ADVECTION ACROSS THE AREA. AN  
OVERALL MODEL BLEND SHOULD WORK FINE FOR TUESDAY AS TEMPERATURES  
RECOVER INTO THE UPPER 60S AND LOWER 70S. COOLER NIGHTS ARE EXPECTED  
THROUGH THE SHORT TERM AS WELL...WITH THE LOWEST TEMPS MONDAY NIGHT  
INTO THE 40S WITH A FEW SPOTS POTENTIALLY SLIPPING INTO THE LOWER  
40S.  
 

 
   
LONG TERM /WEDNESDAY THROUGH SATURDAY/
 
 
ISSUED AT 240 AM EDT SUN MAY 19 2019  
 
ENSEMBLES INDICATE MEAN UPPER RIDGING IS EXPECTED OVER THE OHIO  
VALLEY DURING MOST OF THIS PERIOD. A SHORT WAVE TROUGH MAY PASS  
THROUGH THE GREAT LAKES TOWARDS NEXT WEEKEND, WHICH MAY SUPPRESS  
THE RIDGE SOMEWHAT BY THEN.  
 
ENSEMBLES ARE IN BETTER AGREEMENT IN PUSHING A WEAKENING FRONTAL  
SYSTEM THROUGH THE AREA ON WEDNESDAY. WILL KEEP POPS IN THE  
FORECAST FOR WEDNESDAY TO COVER THIS FRONT.  
 
THERE MAY BE A RELATIVE LULL IN THE PRECIPITATION THREAT WEDNESDAY  
NIGHT, BEFORE ANOTHER FRONT MAY SETTLE INTO THE AREA TOWARDS THE  
END OF THE EXTENDED. WILL HOLD ONTO POPS IN THE THURSDAY TO  
SATURDAY TIME FRAME, BUT AT THIS POINT, IT APPEARS THE BETTER  
PRECIPITATION THREAT MAY BE NEXT FRIDAY AND SATURDAY.  
 

 
   
AVIATION /DISCUSSION FOR THE 191200Z TAFS/
 
 
ISSUED AT 635 AM EDT SUN MAY 19 2019  
 
SHORT TERM MODEL DATA SUGGEST AN AREA OF ORGANIZED LIFT MOVING OUT  
OF THE ARKANSAS REGION WILL BE MOVING OVER THE TERMINALS FROM THE  
LATE MORNING INTO THE MID AFTERNOON HOURS. FAIRLY WIDESPREAD  
RAIN, AND POSSIBLY SOME EMBEDDED LIGHTNING STRIKES, IS EXPECTED IN  
THE VICINITY OF THE TERMINALS DURING THOSE TIMES. BRIEF IFR  
VISIBILITY RESTRICTIONS IN THE HEAVIER PRECIPITATION.  
 
AN ADDITIONAL THREAT FOR SCATTERED CONVECTION MAY DEVELOP OVER THE  
WESTERN TERMINALS TOWARDS EVENING AS A COLD FRONT MOVES IN FROM  
ILLINOIS.  
 
OTHERWISE, AREAS OF MVFR CEILINGS 015-030 EXPECTED TO MOVE IN FROM  
THE SOUTHWEST TOWARDS THE LATE MORNING HOURS. SURFACE WINDS  
190-210 DEGREES WITH OCCASIONAL TO FREQUENT GUSTS AROUND 25 KTS BY  
THE MID MORNING HOURS. GUSTS IN EXCESS OF 30 KTS POSSIBLE BY THE  
MID TO LATE AFTERNOON HOURS.  
 

 
   
IND WATCHES/WARNINGS/ADVISORIES
 
 
NONE.  

 
 

 
 
SYNOPSIS...RYAN  
NEAR TERM...RYAN  
SHORT TERM...RYAN  
LONG TERM....JAS  
AVIATION...JAS  
 
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