Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 251023
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
623 AM EDT SAT APR 25 2015

.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.

&&

.SYNOPSIS...
ISSUED AT 407 AM EDT SAT APR 25 2015

ACTIVE WEATHER TODAY AND TONIGHT AS A FRONTAL SYSTEM MOVES THROUGH
THE MISSOURI AND OHIO VALLEYS WILL GIVE WAY TO DRY AND QUIET WEATHER
UNDER HIGH PRESSURE FOR MUCH OF THE WEEK. COOLER THAN NORMAL
TEMPERATURES WILL MODERATE BACK TO NORMAL BY AROUND MIDWEEK.

&&

.NEAR TERM /TODAY/...

ISSUED AT 407 AM EDT SAT APR 25 2015

FORECAST FOCUS IS ON TIMING OF RAIN/STORMS AND POTENTIAL FOR SEVERE.
ISENTROPIC AND UPPER FORCING WILL INCREASE OVER THE NEXT FEW
HOURS...INCREASING COVERAGE OF RAIN SHOWERS ACROSS THE AREA
ESPECIALLY IN THE SOUTHWEST HEADING INTO THE MORNING. INSTABILITY
ALOFT WILL MOVE IN FROM THE WEST AND COULD SEE ISOLATED EMBEDDED
THUNDERSTORMS WITHIN SOME OF THE SHOWERS BEFORE 12Z.

DURING THE MORNING AN UPPER SHORTWAVE WILL MOVE THROUGH CENTRAL
INDIANA AND RAIN WILL OVERSPREAD THE ENTIRE AREA. AGAIN WITH SOME
ELEVATED INSTABILITY EXPECT TO SEE INITIALLY ISOLATED THUNDERSTORMS
OVER THE WEST AND SOUTH AND THEN BY 15Z OR SO THE RISK FOR
THUNDERSTORMS WILL COVER THE ENTIRE AREA. INSTABILITY PROGS REMAIN
GREATEST ACROSS THE SOUTH THROUGH THE DAY SO INCREASED THUNDER
COVERAGE TO SCATTERED FOR THE SOUTHERN HALF OR SO OF THE AREA BY
18Z...AND IN THE SOUTHWEST AND SOUTHERN COUNTIES WENT AHEAD WITH
JUST THUNDERSTORM WORDING.

BASED ON MODELS FIELDS AND UPPER FORCING COULD SEE A LULL IN
ACTIVITY FOR A BIT THIS AFTERNOON. AT THIS POINT THE MOST LIKELY
TIMING FOR A LULL WOULD BE IN THE 17-21Z TIMEFRAME. NOT CONFIDENT
ENOUGH OF THIS EXACT TIMING/PLACEMENT ACROSS THE AREA TO GO ANY
LOWER THAN LIKELY POPS THOUGH WITH THE SURFACE LOW MOVING FROM
MISSOURI TO SOUTHERN ILLINOIS/WESTERN KENTUCKY DURING THIS TIME.

IT LOOKS LIKE THE FORECAST AREA WILL STAY NORTH OF THE WARM FRONT
FOR THE MAJORITY IF NOT ALL OF THIS EVENT SO THUNDERSTORM ACTIVITY
SHOULD REMAIN ELEVATED. THE POSSIBLE EXCEPTION TO THIS WOULD BE IN
THE FAR SOUTHWESTERN COUNTIES WHERE THE WARM FRONT GETS CLOSE AROUND
18Z OR SO AND SOME DRY AIR COULD WORK IN ALOFT ALLOWING FOR LESS
CLOUD COVER AND THE POTENTIAL FOR INSTABILITY TO BECOME SURFACE
BASED. THINK THIS IS AN OUTSIDE CHANCE AT BEST AND STILL THINK
STRONGEST AND MOST WIDESPREAD SEVERE THREAT WILL REMAIN OUT OF THE
FORECAST AREA. THAT SAID THE UPPER JET MOVING THROUGH WILL GIVE A
BOOST TO CONVECTION IN THE SOUTHERN COUNTIES AND THERE WILL BE
FAVORABLE LOW LEVEL SHEAR. THUS THINK ISOLATED SEVERE THREAT
REMAINS IN THE SOUTHWEST AND SOUTH.

ONE OTHER CONCERN TO NOTE ABOUT THE RAIN TODAY IS THE POTENTIAL FOR
SOUTHERN STORMS TO ROB MOISTURE FROM MAKING IT TO CENTRAL INDIANA.
RIGHT NOW HAVE RAINFALL TOTALS OF AROUND HALF AN INCH NORTHEAST TO
AROUND AN INCH AND A HALF SOUTHWEST BUT THAT COULD BE OVERDOING IT
IF THE AFOREMENTIONED SCENARIO DEVELOPS.

&&

.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...

ISSUED AT 407 AM EDT SAT APR 25 2015

AS TONIGHT BEGINS THE SURFACE LOW WILL BE NEAR SOUTHERN
ILLINOIS/WESTERN KENTUCKY WITH A WARM FRONT GENERALLY NEAR OR SOUTH
OF THE OHIO RIVER. A SHORTWAVE TROUGH WILL BE MOVING THROUGH THE
AREA SO EXPECT RAIN TO BE ONGOING AT THE BEGINNING OF THE TONIGHT
PERIOD. THERE IS SOME UNCERTAINTY REGARDING HOW MUCH INSTABILITY
WILL BE LEFT TO WORK WITH BUT MODELS ARE SHOWING SOME POSITIVE
MUCAPES IN THE FAR SOUTHERN COUNTIES SO WILL CONTINUE WITH AN
ISOLATED THUNDER MENTION THERE THROUGH 3Z. AFTER THAT THE CENTER OF
THE SURFACE LOW MOVES PRETTY RAPIDLY OFF TO THE EAST AND SHOULD SEE
QUICKLY DECREASING POPS ACROSS THE AREA WITH COMPLETELY DRY
CONDITIONS ACROSS THE AREA BY 12Z SUNDAY.

THE REMAINDER OF THE SHORT TERM WILL BE DRY UNDER THE INFLUENCE OF
HIGH PRESSURE. THE HIGH WILL BUILD IN SLOWLY AND UPPER TROUGHING
WILL CONTINUE TO INFLUENCE THE AREA THROUGH MONDAY NIGHT ALLOWING
FOR SOME DIURNAL CU SUNDAY AND MONDAY AFTERNOONS. FOR TEMPERATURES
GUIDANCE IS VERY SIMILAR AND A CONSENSUS WAS USED. MAY NEED TO WATCH
CONDITIONS SUNDAY NIGHT AND MONDAY NIGHT FOR SOME FROST
POTENTIAL.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...

ISSUED AT 243 AM EDT SAT APR 25 2015

ECMWF AND GFS CONTINUE TO KEEP A SURFACE LOW PRESSURE SYSTEM
PASSING THROUGH THE DEEP SOUTH ON TUESDAY AND WEDNESDAY. GULF
MOISTURE AND BEST FORCING REMAINS WELL SOUTH OF THE OHIO VALLEY.
MEANWHILE ALOFT...WEAK RIDGING REMAINS IN PLACE ACROSS INDIANA
UNTIL WEDNESDAY. THE ECMWF SHOWS A DEEP UPPER LOW SINKING OUT OF
THE GREAT LAKES AND INTO INDIANA ON WEDNESDAY...HOWEVER...MOISTURE
REMAINS UNAVAILABLE AND LOWER LEVEL FEATURES ARE POORLY ORGANIZED.
SUPERBLEND HINTS AT LOW CHC POPS AT THIS FEATURE...WHICH DOES NOT
APPEAR UNREASONABLE GIVEN THE LACK OF COORDINATION OF FEATURES.
THUS CONFIDENCE IS LOW. THE REST OF THE FORECAST PERIOD LOOKS DRY
AS UPPER RIDGING AND HIGH PRESSURE THEN BUILDS INTO THE AREA BY FRIDAY
AS THE NEXT WEEKEND BEGINS.

&&

.AVIATION /DISCUSSION FOR THE 251200Z TAFS/...

ISSUED AT 618 AM EDT SAT APR 25 2015

DETERIORATING FLYING CONDITIONS AS MVFR TO IFR CIGS ARE EXPECTED
TO ARRIVE TODAY.

LOW PRESSURE OVER KANSAS IS EXPECTED TO TREK INTO THE OHIO VALLEY
TODAY. THE LOW IS EXPECTED TO PUSH TOWARD THE SOUTHERN PARTS OF
CENTRAL INDIANA BY THIS EVENING. AS THE SYSTEM APPROACHES...A WARM
FRONT WILL SET UP ACROSS CENTRAL INDIANA...PROVIDING AN
OVERRUNNING SITUATION WITH MVFR TO IFR CIGS LATE THIS MORNING AND
THIS AFTERNOON. FORECAST SOUNDINGS THROUGH THIS PERIOD SHOW
SATURATION IN THE LOWER LEVELS.

IMPROVEMENT IS EXPECTED AFTER 06Z TONIGHT AS THE LOW DEPARTS TO
THE EAST AND DRIER AIR ARRIVES. FORECAST SHOW DRY AIR ARRIVING AND
A RETURN TO VFR CONDITIONS BY 12Z SUNDAY.

&&

.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SYNOPSIS...CP
NEAR TERM...CP
SHORT TERM...CP
LONG TERM....PUMA
AVIATION...JP

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