Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 212259
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
659 PM EDT THU AUG 21 2014

.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.

&&

.SYNOPSIS...
ISSUED AT 250 PM EDT THU AUG 21 2014

AN OLD FRONT WILL LINGER IN THE AREA THROUGH THE WEEKEND KEEPING
CHANCES FOR THUNDERSTORMS IN THE FORECAST. AN UPPER RIDGE WILL BRING
HOT AND HUMID CONDITIONS TO THE AREA AS WELL. NEXT WEEK ANOTHER
FRONTAL SYSTEM WILL BRING ADDITIONAL CHANCES FOR RAIN AND WILL
EVENTUALLY BRING A RETURN TO NEAR AVERAGE TEMPERATURES.

&&

.NEAR TERM /THIS EVENING AND TONIGHT/...
ISSUED AT 659 PM EDT THU AUG 21 2014

SEVERE THUNDERSTORM WATCH 472 HAS BEEN ISSUED FOR THE NORTHEAST
THIRD OF THE FORECAST AREA THRU 04Z...MAINLY ALONG AND N/E OF A
LAFAYETTE-NOBLESVILLE-NEW CASTLE LINE. CONVECTIVE CLUSTER CONTINUES
TO INTENSIFY DOWNWIND OF THE CHICAGO METRO. MESOANALYSIS SHOWING
THESE STORMS SHOULD TRACK E/SE AND EVENTUALLY COULD END UP MOVING
MORE SE AS THEY PROPAGATE ALONG THE THETA E RIDGE AND INSTABILITY
AXIS JUST SOUTH OF THE REMNANT WARM FRONT. HAVE BUMPED UP TO A
PERIOD OF LIKELY POPS THIS EVENING WITHIN THE WATCH AREA...WITH
GREATEST IMPACTS EXPECTED FROM KOKOMO TO MUNCIE.

ELEVATED CORES WITHIN MOST INTENSE CELLS WILL CERTAINLY POSE A HAIL
RISK...BUT THE DAMAGING WIND POTENTIAL IS GREATEST WITH SOME CONCERN
THAT CONVECTIVE COMPLEX WILL MATURE ENOUGH TO PRODUCE A WELL
DEVELOPED COLD POOL. ALREADY HAVE SEEN A COUPLE REPORTS OF 60MPH
WINDS OUT OF THE SOUTH CHICAGO SUBURBS. IN ADDITION TO THE WIND
THREAT...OPPRESSIVE CONDITIONS SUPPORTING TORRENTIAL RAINFALL WITH
THESE STORMS. FLOODING CONCERNS LIKELY TO BE ENHANCED OVER NORTHEAST
COUNTIES WHICH RECEIVED 2-3 INCHES FROM STORMS THIS MORNING. THIS
ROUND OF STORMS WILL ADD TO THE IMPRESSIVE LIGHTNING SHOWS
EXPERIENCED OVER THE LAST 48 HOURS AS WELL. ANY EVENING OUTDOOR
ACTIVITIES WILL BE IMPACTED.

FINALLY...EXPECT MOST OF INDY METRO AND POINTS FURTHER S/W WILL
REMAIN LARGELY DRY THROUGH THE EVENING AS LAPS SOUNDINGS INDICATE
PRESENCE OF A DEEPER LAYER OF WARM AIR IN THE MID LEVELS. ANY
OUTFLOWS DROPPING TO THE S/SW OUT OF THESE STORMS MAY SERVE TO
PROMOTE NEW DEVELOPMENT LATER THIS EVENING...ESPECIALLY AS THE LOW
LEVEL JET ORGANIZES AND CAPPING WEAKENS WITH 700MB TEMPS SLIPPING
BACK A BIT.

PERTINENT PORTIONS OF AFTERNOON DISCUSSION FOLLOWS.

OVERNIGHT AN UPPER WAVE WILL ROTATE AROUND THE UPPER HIGH AND
WILL BRING SOME ADDITIONAL FORCING. NOT CONFIDENT ENOUGH TO GO
LIKELY POPS...BUT WILL GO HIGH CHANCE NORTH /CLOSER TO THE ENERGY/
TO DRY EXTREME SOUTHWEST /CLOSEST TO THE UPPER HIGH/.

THE HOT AND HUMID CONDITIONS TO THE SOUTHWEST MAY PROVIDE SOME
DECENT INSTABILITY THIS EVENING...SO SOME STORMS MAY BECOME SEVERE
PER STORM PREDICTION CENTER.

FOR TEMPERATURES TONIGHT WENT A LITTLE COOLER THAN MOS ACROSS THE
NORTHEAST WHERE MORE RAIN IS POSSIBLE...OTHERWISE GENERALLY STAYED
CLOSE TO MAV MOS.

&&

.SHORT TERM /FRIDAY THROUGH SUNDAY/...
ISSUED AT 250 PM EDT THU AUG 21 2014

FOCUS IS ON RAIN CHANCES AND HEAT THROUGH THE PERIOD. MODELS ARE
STRUGGLING WITH PLACEMENT OF CONVECTION BUT ALL GENERALLY SHOW THE
IDEA. STUCK WITH A BLEND.

OVERNIGHT CONVECTION COULD LINGER FRIDAY MORNING...THEN MORE CAN
DEVELOP DURING THE AFTERNOON WITH AN OLD FRONT STILL IN THE AREA.
WILL GO CHANCE POPS NORTHEAST TO DRY FAR SOUTHWEST.

WITH FRONT AROUND THE AREA AND POTENTIAL FOR WAVES MOVING AROUND THE
UPPER HIGH...KEPT SIMILAR POPS FRIDAY NIGHT.

UPPER HIGH GRADUALLY GETS MORE CONTROL OVER THE AREA SATURDAY INTO
SUNDAY...HOWEVER MODELS STILL TRY AND CREATE SOME SCATTERED
CONVECTION ACROSS THE AREA. FEEL THAT THIS IS REASONABLE WITH MOST
INFLUENCE OF UPPER HIGH BEING FELT TO THE SOUTHWEST OF THE AREA.

WENT LOW CHANCE POPS MOST AREAS SATURDAY...WITH ONLY SLIGHT CHANCE
POPS SATURDAY NIGHT AND SUNDAY WITH THE UPPER HIGH GAINING MORE
INFLUENCE.

FOR TEMPERATURES...MAV MOS LOOKS TOO WARM FRIDAY GIVEN SOME CLOUD
COVER FROM EXPECTED CONVECTION. WENT CLOSER TO MET MOS. WENT WITH A
BLEND OF MODELS FOR LOWS FRIDAY NIGHT. MAV LOOKS BETTER SATURDAY
WITH MORE SUN SO STAYED CLOSE MOST AREAS.

HEAT INDICES WILL GET NEAR 100 MANY AREAS THIS WEEKEND WITH THE
RELATIVELY HIGH DEWPOINTS.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
ISSUED AT 250 PM EDT THU AUG 21 2014

THE LONG TERM PERIOD WILL START OUT DRY WITH RIDGING ALOFT AND
CENTRAL INDIANA BETWEEN FRONTAL BOUNDARIES AT THE SURFACE.  THE
RIDGE WILL SLOWLY START TO BREAK DOWN BY TUESDAY THOUGH AS A BROAD
UPPER TROUGH TRAVERSES THE NORTHERN PLAINS.  MEANWHILE...A FRONTAL
BOUNDARY AT THE SURFACE WILL MEANDER OVER THE GREAT LAKES
REGION...WITH CENTRAL INDIANA IN THE WARM SECTOR MOST OF THE TIME.
AS A RESULT...THERE WILL BE DAILY CHANCES FOR PRECIP FROM TUESDAY
THROUGH THURSDAY.  CHANCES WILL BE HIGHEST ON THURSDAY WITH SUPPORT
FROM THE UPPER TROUGH IN ADDITION TO DIURNAL ENHANCEMENT.  FOR
NOW...LATEST INITIALIZATION CAPTURES PATTERN WELL WITH CHANCE POPS
DURING THIS TIME FRAME.

TEMPS...HOT CONDITIONS WILL PERSIST THROUGH THE EXTENDED PERIOD AS
THE UPPER RIDGE DOMINATES MOST OF THE REGION.  SOUTHERLY FLOW WILL
CONTRIBUTE TO HIGH TEMPERATURES SOARING INTO THE LOW TO MID 90S WITH
OVERNIGHT LOWS IN THE UPPER 60S/LOW 70S.  TEMPS WILL BECOME CLOSER
TO NORMAL LATE IN THE PERIOD WHEN THE RIDGE BREAKS DOWN.

&&

.AVIATION /DISCUSSION FOR THE 21/21Z IND TAF UPDATE/...

ISSUED AT 436 PM EDT THU AUG 21 2014

RAISED WINDS A FEW KNOTS AND IMPROVED TO VFR BASED ON TRENDS.

PREVIOUS DISCUSSION FOLLOWS...

THE MAIN CHALLENGE OF TAF PERIOD IS TIMING OF ANY POSSIBLE
CONVECTION. AT THIS TIME...SHOWERS AND THUNDERSTORMS HAVE MOVED
EAST OF ALL TAF SITES...BUT A WARM FRONT AND UNSTABLE ENVIRONMENT
WILL BE CONDUCIVE TO MORE DEVELOPMENT LATER IN THE TAF PERIOD.
BEST CHANCES WILL BE AT KLAF AND KIND AFTER FRI 06Z WHEN A WEAK
VORT MAX DRIFTS OVER THE AREA. THIS EXTRA FORCING COMBINED WITH
LIFT FROM THE FRONT WILL MAKE DEVELOPMENT MOST FAVORABLE OVER
THOSE NORTHERN TAF SITES IN THE FRI 06-12Z TIME FRAME. OUTSIDE OF
ANY SHOWERS AND THUNDERSTORMS...CONDITIONS WILL BE VFR. WINDS WILL
BE WEST/SOUTHWESTERLY AT 3 TO 8 KTS.

&&

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

$$

SYNOPSIS...50
NEAR TERM...RYAN/50
SHORT TERM...50
LONG TERM...TDUD
AVIATION...TDUD/MK

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