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000
FXUS63 KIND 181421
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
1021 AM EDT TUE JUN 18 2013

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

&&

.SYNOPSIS...
ISSUED AT 402 AM EDT TUE JUN 18 2013
AN UPPER WAVE WILL MOVE THROUGH TODAY KEEPING CHANCES FOR
THUNDERSTORMS IN THE FORECAST. UPPER RIDGING BUILDS IN TONIGHT AND
BRINGS DRY WEATHER TO THE AREA INTO THE WEEKEND. THE UPPER RIDGE
COULD START TO BREAK DOWN OVER THE WEEKEND AND THIS ALLOWS LOW
CHANCES FOR THUNDERSTORMS TO MAKE THEIR WAY BACK INTO THE FORECAST
FROM SATURDAY NIGHT ON. NEAR NORMAL TEMPERATURES WILL BE IN PLACE
FOR THE NEXT COUPLE OF DAYS BUT VERY WARM HUMID AIR ARRIVES IN
TIME FOR THE WEEKEND.

&&

.NEAR TERM /REST OF TODAY/...

ISSUED AT 930 AM EDT TUE JUN 18 2013

SHOWERS ACROSS THE SOUTHERN FORECAST AREA CONTINUE TO WEAKEN...BUT
SOME ISOLATED SHOWERS HAVE DEVELOPED AND MOVED INTO THE NORTHERN
FORECAST AREA. HAVE ADDED SLIGHT CHANCE POPS THIS MORNING TO THE
NORTHERN FORECAST AREA...BUT THESE SHOWERS DO NOT LOOK TO LAST LONG
PER LATEST TRENDS. KEPT LOW POPS ACROSS THE SOUTH AS THE SHOWERS
CONTINUE TO WEAKEN.

REMAINDER OF FORECAST STILL LOOKS ON TRACK. MOST MODELS CONTINUE TO
SHOW DEVELOPMENT OF SCATTERED SHOWERS AND STORMS AS UPPER SHORTWAVE
MOVES IN THIS AFTERNOON. MOST OF AREA REMAINS IN SLIGHT RISK FOR
SEVERE STORMS PER STORM PREDICTION CENTER.

PREVIOUS DISCUSSION FOLLOWS...
FORECAST FOCUS FOR TODAY IS ON POPS AND SEVERE THUNDERSTORM CHANCES.
A COLD FRONT WILL MOVE THROUGH THE AREA TODAY ALONG WITH AN UPPER
SHORTWAVE. MODELS ARE SHOWING GOOD INSTABILITY WITH SFC BASED CAPES
OF 1000-2000 AND FAVORABLE MID LEVEL LAPSE RATES. FRONTAL FORCING IS
FAIRLY WEAK...BUT A DECENT 500 MB SHORTWAVE SHOULD PROVIDE THE EXTRA
LIFT NEEDED. SHEAR LOOKS MARGINAL AT BEST THOUGH AND THIS WILL BE
THE LIMITING FACTOR FOR WIDESPREAD SEVERE. THINK LOW END SEVERE HAIL
AND DAMAGING WINDS WILL BE THE MAIN THREATS.

AS FAR AS POPS ARE CONCERNED MET NUMBERS ARE MUCH HIGHER THAN MAV.
NAM/S FEATURES ARE MUCH STRONGER WITH THIS SYSTEM THAN OTHER
MODELS SO GENERALLY STUCK CLOSER TO THE GFS/MAV NUMBERS THAT WERE
IN MUCH BETTER AGREEMENT WITH ECMWF/GEM ON FEATURES. BEST TIMING
FOR THUNDERSTORMS WILL BE LATE AFTERNOON INTO EARLY EVENING WHEN
INSTABILITY PEAKS AND THE SHORTWAVE ARRIVES. FOR TEMPERATURES
GUIDANCE NUMBERS WERE SIMILAR SO USED AN AVERAGE.

&&

.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...

ISSUED AT 402 AM EDT TUE JUN 18 2013

FORECAST FOCUS IS ON POPS EARLY TONIGHT AND THEN TEMPERATURES.
SOME DISAGREEMENT AMONGST THE MODELS ON HOW FAST PRECIP CHANCES WILL
MOVE OUT OF THE AREA TONIGHT...WITH THE NAM HOLDING ON TO PRECIP
LONGER THAN THE GFS. WITH THE SHORTWAVE JUST ARRIVING IN THE WESTERN
COUNTIES AT 0Z SO EVEN THOUGH THE COLD FRONT WILL BE THROUGH THINK
SOME CHANCES WILL CONTINUE IN THE SOUTHEAST FOR A COUPLE OF HOURS.
INSTABILITY WILL COME TO AN END FAIRLY QUICKLY THOUGH WITH END OF
SOLAR HEATING AND ADVECTION IN OF DRY AIR SO WILL GO DRY ACROSS THE
AREA BY MIDNIGHT. AFTER THAT UPPER RIDGING AND SURFACE HIGH PRESSURE
BUILDS IN AND THE REST OF THE SHORT TERM WILL BE DRY.

TONIGHT WITH SKIES CLEARING AFTER MIDNIGHT AND COLD DRY ADVECTION IN
PLACE FAVORED COOLER MAV NUMBERS. FOR HIGHS WEDNESDAY PREFERRED THE
COOLER MET NUMBERS THAT BETTER MATCH THE COOLER 850 MB TEMPERATURES
OF 11-13C. PREFERRED WARMER THAN GUIDANCE TEMPS FOR WEDS NIGHT WITH
WARM ADVECTION AND POSSIBLY SOME CIRRUS. GUIDANCE CONSENSUS FOR
THURSDAY AND MODEL CONSENSUS FOR THURSDAY NIGHT MATCHED THE UPPER
RIDGING PATTERN WELL.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...

ISSUED AT 402 AM EDT TUE JUN 18 2013

AN UPPER RIDGE WILL DOMINATE OUR WEATHER THROUGH THE LONG TERM AS
ITS AXES MOVES EAST FROM THE MISSISSIPPI RIVER VALLEY EARLY ON
TO THE TENNESSEE AND OHIO VALLEY BY DAY 7.   MODELS INDICATE A
COUPLE OF UPPER DISTURBANCES WILL COME OVER THE TOP OF THE UPPER
RIDGE WITH ONE MOVING BY SATURDAY NIGHT AND SUNDAY AND A STRONGER
ONE TOWARDS THE END OF DAY 7.   CONFIDENCE ON EXACT TIMING IS LOW...
SO ONLY MADE SLIGHT CHANGES FROM ALL BLEND POPS.

MODELS INDICATE 850 MB TEMPERATURES WILL WARM UP TO +18 TO +20
CELSIUS OVER THE WEEKEND AND COOL JUST SLIGHTLY DAY 7 WITH THE
SECOND UPPER DISTURBANCE.  RAISED MAX TEMPERATURES A DEGREE OR TWO
IN OVER WEEKEND THE WEEKEND GIVEN THE WARM 850 MB TEMPERATURES.
OTHERWISE...ONLY SLIGHT CHANGES MADE TO ALL BLEND TEMPERATURES.

&&

.AVIATION /DISCUSSION FOR THE 181200Z TAFS/...

ISSUED AT 1020 AM EDT TUE JUN 18 2013

1430Z UPDATE...NO CHANGES ATTM. PREV DISC FOLLOWS...

VFR THROUGH THE PERIOD.

RADAR INDICATES A FEW SHOWERS VCNTY KBMG AT THE START OF THE
FORECAST PERIOD.  OTHERWISE...LOOK FOR SCATTERED CU TO DEVELOP
ACROSS THE AREA THIS MORNING.

AN UPPER AIR DISTURBANCE OVER NORTHEAST IOWA WILL MOVE TO CENTRAL
INDIANA BY THIS EVENING.  THIS DISTURBANCE WILL BE ARRIVING AT TIME
OF MAXIMUM DAYTIME HEATING AND MODELS INDICATE AN UNSTABLE AIRMASS
WILL BE ACROSS OUR REGION. RAPID REFRESH MODEL INDICATES SCATTERED
THUNDERSTORMS WILL BE DEVELOPING BY 19Z-20Z.  SPC HAS CENTRAL
INDIANA UNDER A SLIGHT RISK OF SEVERE STORMS.

WILL MENTION VCTS IN TAFS FROM ABOUT 19Z-01Z TIME FRAME. OTHERWISE...
LOOK FOR SCATTERED CU THIS EVENING AND MOSTLY CLEAR CONDITIONS
AFTER MIDNIGHT AS DRIER AIR SPREADS INTO OUR REGION.

WINDS WILL BECOME NORTH UP TO 10 KNOTS BY MIDDAY AND NORTHEAST
3 TO 7 KNOTS TONIGHT.

&&

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

$$

SYNOPSIS...CP
NEAR TERM...CP/50
SHORT TERM...CP
LONG TERM....JH
AVIATION...SMF/JH

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