000
FXUS63 KIND 201454
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
1050 AM EDT MON MAY 20 2013

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

&&

.SYNOPSIS...
ISSUED AT 300 AM EDT MON MAY 20 2013

A LARGE UPPER LOW CURRENTLY OVER THE PLAINS IS EXPECTED TO BRING
UNSETTLED WEATHER TO THE AREA THROUGH THURSDAY AS IT SLOWLY MOVES
EAST AND WEAKENS WITH TIME. HIGH PRESSURE IS EXPECTED TO BUILD IN
BEHIND THIS SYSTEM TOWARDS THE END OF THE WEEK. ANOTHER FRONTAL
SYSTEM MAY APPROACH THE AREA BY NEXT SUNDAY.

&&

.NEAR TERM /REST OF TODAY/...
ISSUED AT 1045 AM EDT MON MAY 20 2013

OUTFLOW BOUNDARY CURRENTLY MOVING INTO THE WESTERN BORDER ZONES
SEEMS TO BE LOSING ITS EASTWARD PUSH...BUT STILL QUITE A DEWPOINT
GRADIENT ALONG IT WITH DEWPOINTS FALLING INTO THE UPPER 50S BEHIND
BOUNDARY.

REMNANTS OF THIS BOUNDARY MAY MOVE FARTHER INTO THE AREA THIS
AFTERNOON AS IT WEAKENS. CONVECTION MAY DEVELOP ALONG THIS BOUNDARY
LATER THIS AFTERNOON AS AIR MASS IS EXPECTED TO BECOME VERY
UNSTABLE...HOWEVER A MID LEVEL CAP NOTED ON THIS MORNING/S UPPER AIR
MAY HELP SUPPRESS CONVECTION. MODEL DATA WEAKEN THIS CAP BY MID TO
LATE AFTERNOON...BUT SOME QUESTION AS TO WHETHER THIS WILL ACTUALLY
HAPPEN. WILL KEEP CHANCE POPS GOING FOR MAINLY LATER THIS AFTERNOON.
IF STORMS CAN BREAK THE CAP...LAPSE RATES QUITE FAVORABLE FOR
SEVERE...ALTHOUGH DEEP SHEAR CONTINUES TO LOOK RATHER WEAK.

QUITE A BIT OF CLOUD COVER HAS DEVELOPED OVER THE PAST COUPLE OF
HOURS...ALTHOUGH SATELLITE INDICATES SOME THINNING RECENTLY. AS A
RESULT...WILL LOWER THE HIGHS TODAY A COUPLE OF DEGREES.

PREVIOUS DISCUSSION FOLLOWS.

MODELS STILL HINTING AT A WEAK BOUNDARY ORIGINATING FROM CONVECTIVE
ACTIVITY TO THE WEST THAT WILL MOVE INTO THE AREA THIS AFTERNOON. AS
SO...THE AIR MASS WILL BECOME VERY UNSTABLE LATER TODAY WITH LIFTED
INDEXES AROUND -7/-8 AND STEEP LLVL LAPSE RATES. WILL CONTINUE TO
CARRY CHANCE POPS WITH THE HIGHEST AMOUNTS TO THE NORTH. VERY WARM
TEMPERATURES EXPECTED TODAY...AND ALONG WITH THE HIGHER DEW POINTS
WILL MAKE IT FEEL MUCH LIKE A MID SUMMER/S DAY. LEANED CLOSER TO THE
WARMER MET FOR HIGH IN THE UPPER 80S TO AROUND 90.

&&

.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
ISSUED AT 300 AM EDT MON MAY 20 2013

MODELS PROGGING BETTER CHANCES FOR SHOWERS AND THUNDERSTORMS...AND
POTENTIALLY SEVERE FOR TONIGHT...AS MUCH OF THE CWA IS IN A SLIGHT
RISK. BUMPED UP MUCH OF THE FORECAST AREA TO LIKELY BASED ON GOOD
MODEL CONSENSUS.

THE REST OF THE PERIOD LOOKS VERY UNSETTLED WITH ROUNDS OF
CONVECTION MAKING THE POSITION OF THE COLD FRONT HARD TO FIND.
HOWEVER IT APPEARS MODELS HAVE BUMPED UP THE TIMING OF THE MAIN COLD
FRONT TO WED...RATHER THAN WED NIGHT. HAVE LIKELY POPS IN FOR
WED...BUT BEFORE AND AFTER THAT CANNOT REALLY PIN DOWN ANY PERIODS
TO CONCENTRATE HIGH POPS ON...SO WILL CONTINUE TO BROADBRUSH HIGH
CHANCE POPS TUESDAY THRU TUE NIGHT AND AGAIN WED NIGHT.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
ISSUED AT 233 AM EDT MON MAY 20 2013

END OF AN ACTIVE WX PERIOD IS ANTICIPATED IN THE LONG TERM PORTION
OF THE FORECAST...AS LOW PRESSURE PULLS OUT OF THE AREA AND A
BROAD SURFACE RIDGE SETTLES INTO THE REGION DOWNSTREAM OF AN UPPER
RIDGE ACROSS THE CENTRAL PORTION OF THE COUNTRY. NOT OVERLY
PLEASED WITH ALLBLEND INITIALIZATION POPS BEYOND THURSDAY AS IT
WANTS TO INTRODUCE ANOTHER LENGTHY PERIOD OF SLIGHT CHANCE TO
CHANCE POPS OVER THE WEEKEND AND INTO NEXT WEEK...EVEN WITH THIS
SURFACE RIDGE ACROSS THE AREA AND LIMITED IF ANY UPPER LEVEL
SUPPORT FOR PRECIPITATION. HAVE GONE DRY FROM THURSDAY NIGHT ON.

ON TEMPS...EXPECTING NUMBERS CLOSER TO SEASONABLE LEVELS...IF NOT
SLIGHTLY BELOW AT TIMES THROUGHOUT THE PERIOD. IF DRY FORECAST
HOLDS...COULD MAKE FOR A VERY PLEASANT HOLIDAY WEEKEND ACROSS
CENTRAL INDIANA.

&&

.AVIATION /DISCUSSION FOR THE 201500Z IND TAF UPDATE/...

BRIEF MVFR CIGS ARE EXPECTED THE NEXT 1-2 HOURS.  OBSERVATIONAL TRENDS AND
SATELLITE SHOW BKN CU ACROSS SEVERAL OF THE TAF SITES. AS HEATING
CONTINUES CCL/S ARE EXPECTED TO RISE ABOVE 3000FT AND VFR CIGS
WILL BE THE RULE THIS AFTERNOON.

PLENTY OF CAPE AND INSTABILITY STILL APPEAR AVAILABLE THIS
AFTERNOON BASED UPON FORECAST SOUNDINGS. THUS FOR NOW THE ONGOING
VCTS SEEMS REASONABLE.

PREVIOUS DISCUSSION BELOW

/DISCUSSION FOR THE 20/12Z TAFS/...
ISSUED AT 713 AM EDT SUN MAY 19 2013

MVFR CONDITIONS AT SOME SITES EARLY IN THE PERIOD IN FOG AND STRATUS
WILL GIVE WAY TO VFR CONDITIONS LATER TODAY...OUTSIDE OF ANY
POTENTIAL SHOWERS AND THUNDERSTORMS.

WARM MOIST AIRMASS IN PLACE ACROSS THE AREA...PRIMED FOR POSSIBLE
SHOWERS AND STORMS LATER TODAY AND TONIGHT. UNCERTAINTIES IN TIMING
AND COVERAGE PRECLUDE EXPLICIT MENTIONS BEYOND VCTS/CB FROM MIDDAY
ON.

WINDS WILL GENERALLY BE OUT OF THE SOUTH AND WILL BECOME GUSTY
TODAY...INTO THE LOW TO MID 20KT RANGE. GUSTS WILL SUBSIDE THIS
EVENING BUT WINDS WILL REMAIN NEAR 8-10KT.


&&

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

$$

SYNOPSIS...SMF
NEAR TERM...SMF/JAS
SHORT TERM...SMF
LONG TERM....NIELD
AVIATION...NIELD/JP

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