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000
FXUS63 KIND 182015
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
415 PM EDT SAT MAY 18 2013

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

&&

.SYNOPSIS...
ISSUED AT 200 PM EDT SAT MAY 18 2013

A WEAK AREA OF LOW PRESSURE WILL EXIT THE OHIO VALLEY TONIGHT
BRINGING CHANCES FOR SHOWERS AND THUNDERSTORMS TO AN END. A WEAK
RIDGE OF HIGH PRESSURE WILL BUILD ACROSS THE AREA ON
SUNDAY...KEEPING DRY AND WARM WEATHER ACROSS CENTRAL INDIANA THROUGH
THE BEGINNING OF THE WORK WEEK. A FEW STORMY DAYS ARE POSSIBLE
DURING THE MIDDLE OF THE WEEK AS A STRONGER AREA OF LOW PRESSURE
DEVELOPS OVER THE PLAINS STATES AND ALLOWS MORE FAVORABLE CONDITIONS
FOR STORMS ACROSS INDIANA.


&&

.NEAR TERM /TONIGHT/...

ISSUED AT 200 PM EDT SAT MAY 18 2013

SURFACE ANALYSIS EARLY THIS AFTERNOON SHOWS A WEAK AREA OF LOW
PRESSURE OVER WESTERN KENTUCKY. EASTERLY SURFACE FLOW WAS IN PLACE
ACROSS CENTRAL INDIANA WITH TEMPERATURES IN THE UPPER 60S AND
LOWER 70S. SATELLITE IMAGES SHOW ABUNDANT CLOUD COVER ACROSS CENTRAL
INDIANA...HOWEVER THERE WERE A FEW BREAKS. RADAR HAS GONE QUIET.

MAIN FORECAST CHALLENGE WILL BE TRENDING POPS.

NAM AND GFS CONTINUE TO SUGGEST LIMITED FORCING THIS AFTERNOON.
WITH ABUNDANT CLOUD COVER ACROSS THE AREA DAYTIME HEATING APPEARS
TO BE LIMITED...HOWEVER FORECAST SOUNDINGS SHOW CONVECTIVE
TEMPERATURES IN THE MIDDLE TO UPPER 70S. A FEW BREAKS APPEARING IN
THE OVERCAST SEEM TO BE ALLOWING SOME HEATING.

THE WEAK LOW OVER KENTUCKY IS EXPECTED TO PUSH EAST AND DISSIPATE
OVERNIGHT. LOWER LEVEL Q VECTORS CONTINUE TO INDICATE STRONG
DIVERGENCE IN THE LOWER LEVELS.

THUS A FEW ISOLATED SHRA OR TSRA WILL BE POSSIBLE LATE THIS
AFTERNOON AND EARLY THIS EVENING...BUT WILL TRY TO AIM FOR A DRY
FORECAST AFT 00Z SUN AS HEATING IS LOST AND THE LOW CONTINUES TO
PUSH TO THE EAST. GIVEN THE EXPECTED CLOUDS ACROSS THE AREA WILL
TREND LOWS AT OR ABOVE MAVMOS.

&&

.SHORT TERM /SUNDAY THROUGH TUESDAY/...

ISSUED AT 200 PM EDT SAT MAY 18 2013

MAIN FORECAST CHALLENGE DURING THIS PERIOD WILL BE TEMPS.

THROUGH MONDAY...GFS AND NAM BOTH SUGGEST STRONG RIDGING BUILDING
ACROSS THE AREA. FORECAST SOUNDINGS SHOW A GOOD MID LEVEL
INVERSION IN PLACE WHICH SHOULD LIMIT CONVECTION EACH AFTERNOON.
GOOD WARM AIR ADVECTION DURING THE AFTERNOON HOURS SHOW 700MB
TEMPS REACHING 10C BY 00Z MONDAY. THUS WILL TREND TOWARD A DRY
FORECAST. NAM DOES HINT AS SOME UPPER SUPPORT PUSHING OUT OF THE
DEVELOPING LOW OVER THE CENTRAL PLAINS INTO NORTHWEST INDIANA ON
MONDAY AFTERNOON...HOWEVER CONFIDENCE IN THIS FEATURE IS NOT GREAT
AT THIS TIME...AND GFS APPEARS TO BE A BIT SLOWER.

850 MB TEMPS LOOK TO SOAR TO NEAR 14-16C ON SUNDAY AND MONDAY.
EVEN THOUGH SOME AFTERNOON CU WILL BE EXPECTED...PLENTY OF SUN
SHOULD BE SEEN UNDER THE RIDGE. THUS WILL TREND HIGHS ON SUNDAY
AND MONDAY AT OR ABOVE GUIDANCE. MONDAY MAY FEEL LIKE JULY WITH
HIGHS NEAR 90 AT MANY LOCATIONS. GIVEN THE WARM AIR MASS WILL ALSO
TRENDS LOWS AT OR ABOVE GUIDANCE...ESPECIALLY IN THE URBAN HEAT
ISLAND.

GFS AND NAM SUGGEST THE STRONG UPPER LOW OVER THE PLAINS STATES
WILL PUSH CLOSER TO INDIANA ON MONDAY NIGHT AND TUESDAY...EJECTING
SHORT WAVES INTO INDIANA. A WARM AND MOIST AIR MASS WILL BE IN
PLACE AT THE SURFACE WITH DEW POINTS IN THE MIDDLE 60S. MEANWHILE
THE NAM SUGGESTS A WARM FRONT SETTING UP OVER NORTHERN
INDIANA...PROVIDING A FOCUS FOR CONVECTION. FORECAST SOUNDINGS SHOW
GREAT AMOUNTS OF CAPE...OVER 2000 J/KG ON MONDAY NIGHT AND
TUESDAY...WITH VERY FAVORABLE LI/S INDICATING A STEEP LAPSE RATES.
18Z TUESDAY CONVECTIVE TEMPERATURES APPEAR TO BE IN THE UPPER
80S...BUT FALL AS THE AFTERNOON PROGRESSES. SHOULD THE CAP BE
BROKEN...TUESDAY COULD BE A SEVERE WEATHER DAY. THUS WILL
CONTINUE WITH CHANCES FOR TSRA BOTH ON MONDAY NIGHT AND TUESDAY.
AGAIN WITH THE VERY WARM AIR MASS IN PLACE WILL TREND HIGHS AND
LOWS AT OR ABOVE GUIDANCE.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...

ISSUED AT 200 PM EDT SAT MAY 18 2013

ENSEMBLES ARE IN FAIRLY GOOD AGREEMENT ON THE UPCOMING WEATHER
PATTERN OVER THE SECOND HALF OF NEXT WEEK. UPPER LOW INITIALLY OVER
THE PLAINS AT THE TAIL END OF THE SHORT TERM IS EXPECTED TO SLOWLY
SHIFT EAST ACROSS THE AREA DURING THIS PERIOD. ENSEMBLES ARE A
LITTLE SLOWER WITH THIS FEATURE THAN THEY WERE YESTERDAY...WITH A
FEW MEMBERS LINGERING THE EFFECTS OF THE UPPER LOW INTO FRIDAY. WILL
CONTINUE TO HIT THE POPS HARDEST ON WEDNESDAY...BUT IF CURRENT
TRENDS CONTINUE...MAY NEED TO INCREASE POPS ON THURSDAY AS WELL.
WILL ALSO KEEP SOME CHANCE POPS ON FRIDAY TO COVER THE POTENTIAL FOR
THE SLOWER SOLUTIONS.

WILL GO WITH A DRY FORECAST BY NEXT SATURDAY AS THE UPPER LOW
CONTINUES TO SHIFT EAST...HOWEVER THERE ARE A FEW MEMBERS THAT
SUGGEST THE TAIL END OF THE UPPER TROUGH MAY CUTOFF OVER THE OHIO
VALLEY NEXT WEEKEND. NOT THE MORE LIKELY SOLUTION AT THIS
POINT...BUT SOMETHING TO WATCH.


&&

.AVIATION /DISCUSSION FOR THE 182100Z IND TAF UPDATE/...
ISSUED AT 415 PM EDT SAT MAY 18 2013

PULLED VCTS AT LEAST FOR NOW AS DEVELOPMENT HAS BEEN WELL SOUTH AND
SHOWERS WERE ONLY DRIFTING NORTH.

PREVIOUS DISCUSSION FOLLOWS...

CONVECTIVE TEMPERATURES SHOULD BE REACHED OVER THE NEXT 2-3 HOURS
SO EXPECTING SCATTERED CONVECTION TO DEVELOP BY THEN. SHORT TERM
MODEL DATA SUGGESTS THERE MAY BE A WEAK VORTICITY LOBE HANGING
ACROSS THE AREA AS WELL...WHICH MAY AID IN DEVELOPMENT AS WELL. DUE
TO EXPECTED SCATTERED NATURE OF THE CONVECTION...FOR NOW WILL GO
WITH SCATTERED CB/S 181900Z-190100Z. BRIEF IFR VISIBILITY
RESTRICTIONS/GUSTY SHIFTING WINDS POSSIBLE IN THE VICINITY OF THE
HEAVIER CELLS. CONVECTIVE CLOUD BASES 020-030.

OUTSIDE OF CONVECTION...CEILINGS GENERALLY ABOVE 050 WITH NO WIND
ISSUES EXPECTED THROUGH LATE EVENING. AREAS MVFR VISIBILITY
RESTRICTIONS IN LIGHT FOG MAY DEVELOP AFTER ABOUT 190500Z.

&&

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

$$

SYNOPSIS...PUMA
NEAR TERM...PUMA
SHORT TERM...PUMA
LONG TERM....JAS
AVIATION...JAS/MK

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