Area Forecast Discussion
Issued by NWS Indianapolis, IN

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688
FXUS63 KIND 062215
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
615 PM EDT FRI MAY 6 2016

.UPDATE...

THE AVIATION SECTION HAS BEEN UPDATED BELOW.

&&

.SYNOPSIS...
ISSUED AT 142 PM EDT FRI MAY 6 2016

TONIGHT THE QUICK REPRIEVE FROM THE RECENT WET WEATHER WILL
LINGER. HOWEVER...SHOWERS AND THUNDERSTORMS ARE EXPECTED TO RETURN
TO THE FORECAST ON SATURDAY AFTERNOON THROUGH MUCH OF NEXT WEEK.

HIGH PRESSURE SOUTH OF INDIANA WILL EXIT TO THE SOUTHEAST ON
SATURDAY AS A COLD FRONT APPROACHES FROM THE UPPER MIDWEST.
SHOWERS AND STORMS ARE EXPECTED TO DEVELOP ALONG AND AHEAD OF THE
FRONT ON SATURDAY AFTERNOON AND EVENING AS IT PUSHES THROUGH THE
STATE.

THE FRONT IS EXPECTED TO STALL NEAR THE OHIO RIVER ON
SUNDAY...LINGERING THERE UNTIL MONDAY WHEN IT RETURNS TO CENTRAL
INDIANA AS A WARM FRONT. THIS WILL RESULT IN MORE CHANCES FOR RAIN
SHOWERS AS THE WEEKEND ENDS AND THE NEW WORK WEEK BEGINS.

THE WARM FRONT SHOULD STAY WITH INDIANA INTO WEDNESDAY...THEN BE
REPLACED BY A COLD FRONT. ANOTHER HIGH PRESSURE SYSTEM WILL ARRIVE
THURSDAY.

&&

.NEAR TERM /TONIGHT/...
ISSUED AT 142 PM EDT FRI MAY 6 2016

SURFACE ANALYSIS EARLY THIS AFTERNOON SHOWS HIGH PRESSURE CENTERED
OVER ARKANSAS...EXTENDING A RIDGE OF HIGH PRESSURE NORTHEAST INTO
INDIANA. LIGHT NW FLOW WAS IN PLACE ACROSS INDIANA WITH
COMFORTABLE DEW POINTS IN THE MIDDLE 40S. LOW PRESSURE WAS FOUND
ACROSS WESTERN ONTARIO...WITH A COLD FRONT SAGGING SOUTHWEST
ACROSS MINNESOTA AND INTO THE DAKOTAS. ALOFT THE WATER VAPOR
IMAGERY SHOWED RIDGING IN PLACE OVER THE GREAT LAKES WHICH IS PART
OF A LARGER OMEGA BLOCK ACROSS THE ENTIRE UNITED STATES.

MAIN FORECAST CHALLENGE TONIGHT WILL BE TEMPS.

FORECAST SOUNDINGS AND TIME HEIGHTS MAINTAIN A DRY COLUMN TONIGHT
AS THE SURFACE HIGH PRESSURE SYSTEM SETTLES ACROSS THE DEEP SOUTH.
WITH GOOD SUBSIDENCE WILL CONTINUE TO TREND TOWARD A MOSTLY CLEAR
SKY. AS FOR TEMPS...STRONG WARM AIR ADVECTION IS EXPECTED
OVERNIGHT AS THE GFS AND NAM SUGGEST A 850MB THERMAL RIDGE IN
APPROACHING AHEAD OF THE COLD FRONT. IN FACT...NAM SUGGESTS 850MB
TEMPS REACHING 14-15C BY 12Z SATURDAY. THUS WILL NOT EXPECT LARGE
TEMPERATURE FALLS OVERNIGHT...AND WILL TREND LOWS AT OR ABOVE
MAVMOS.

&&

.SHORT TERM /SATURDAY THROUGH MONDAY/...
ISSUED AT 142 PM EDT FRI MAY 6 2016

ACTIVE WEATHER IS EXPECTED TO RETURN TO CENTRAL INDIANA ON
SATURDAY. MODELS CONTINUE TO SUGGEST THE COLD FRONT WILL PUSH
SOUTH ACROSS CENTRAL INDIANA DURING THE AFTERNOON. FAVORABLE LOWER
LEVEL CONVERGENCE ALONG WITH DAYTIME HEATING LOOKS TO PROVIDE
FAVORABLE CONDITIONS FOR SHOWER AND STORM DEVELOPMENT. FORECAST
SOUNDINGS ON SATURDAY AFTERNOON SUGGEST MUCAPES IN EXCESS OF 2000
J/KG...ALONG WITH STEEP...FAVORABLE LAPSE RATES FOR CONVECTION.
CONVECTIVE TEMPS NEAR 80 APPEAR VERY REACHABLE. THUS WILL TREND
POPS AT OR ABOVE MAVMOS...MAINLY DURING THE AFTERNOON HOURS AS
CONVECTIVE TEMPS ARE REACHED. GIVEN THE WARM AIR ADVECTION AND
DECENT DAY OF HEATING AHEAD OF THE FRONT...WILL TREND HIGHS RIGHT
NEAR CONVECTIVE TEMPS.

SATURDAY NIGHT AND SUNDAY THE COLD FRONT LOOKS TO STALL ACROSS SOUTHWEST
INDIANA. THE UPPER FLOW THEN ALSO BEGINS TO BREAK DOWN...ALLOWING
NW FLOW TO OCCUR OVER THE FRONT. MINIMAL SUPPORT IS SEEN AT THIS
TIME...HOWEVER LOWER LEVEL CONVERGENCE REMAINS FAVORABLE ACROSS
THE SOUTHWEST...ALONG WITH FAVORABLE CONVECTIVE TEMPS AGAIN ON THE
WARM SIDE OF THE FRONT. MEANWHILE...BY SUNDAY...WEAK HIGH PRESSURE
SHOULD KEEP MUCH OF THE NORTH AND EAST PARTS OF CENTRAL INDIANA
DRY AND COOLER. THUS WILL FOCUS POPS ON SATURDAY NIGHT MAINLY
ACROSS THE SOUTH PARTS OF THE FORECAST AREA...AND ACROSS THE
SOUTHWEST ON SUNDAY. WILL STICK CLOSE TO GUIDANCE TEMPS ON LOWS
AND HIGHS...EXPECT NEAR THE FRONT WHERE WE WILL TREND LOWS WARMER
AND HIGHS COOLER GIVEN THE EXPECTED CLOUDS AND POSSIBLE PRECIP.

SUNDAY NIGHT AND MONDAY THE FLOW ALOFT BECOMES MORE SOUTHWEST AND
THE GFS AND NAM BOTH SEVERE SEVERAL SHORT WAVES PUSHING TOWARD
INDIANA FROM THE SOUTHWEST. THE LINGERING FRONTAL BOUNDARY WILL
ACT AS A FOCUS FOR DEVELOPING PRECIPITATION. FORECAST SOUNDINGS ON
SUNDAY NIGHT SHOW DEEP SATURATION AMID AN OVERRUNNING TYPE
PATTERN. 305K GFS ISENTROPIC SURFACE SUGGESTING EXCELLENT UPGLIDE
ACROSS INDIANA WITH A SURGE OF SPECIFIC HUMIDITIES IN EXCESS OF 5
G/KG. THUS WILL ONCE AGAIN TREND POPS HIGHER THAN GUIDANCE ON
SUNDAY NIGHT AS THIS WARM FRONT WITH DYNAMICS LIFTS NORTH ACROSS
CENTRAL INDIANA. GIVEN THE EXPECTED CLOUDS...RAIN AND WARMER AIR
MOVING IN...WILL TREND LOWS WARMER THAN MAVMOS.

MODELS THEN SUGGEST THE WARM FRONT LINGERING ACROSS THE NORTHERN
PARTS OF CENTRAL INDIANA ON MONDAY AS YET ANOTHER SHORTWAVE AMID
THE SOUTHWEST FLOW ALOFT PUSHES THROUGH CENTRAL INDIANA.
FURTHERMORE...FORECAST SOUNDINGS ON MONDAY SUGGEST STEEP LAPSE
RATES AGAIN...WITH AMPLE CAPE...NO CAP AND EASILY ATTAINED
CONVECTIVE TEMPERATURES. THUS WILL AGAIN NEED TO INCLUDE
POPS...PROBABLY AT OR ABOVE MEXMOS.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
ISSUED AT 247 PM EDT FRI MAY 6 2016

MODELS CONTINUE TO DEPICT ALMOST DAILY CHANCES FOR SHOWERS AND
STORMS IN THE LONG TERM PERIOD AFTER THE BREAKDOWN OF BLOCKING
PATTERN CURRENTLY IN PLACE.

HIGHEST POPS ARE MERITED EARLY IN THE PERIOD AS A LARGE LOW PRESSURE
SYSTEM MOVES OUT OF THE CENTRAL PORTION OF THE COUNTRY TOWARD THE
GREAT LAKES. LESSER CHANCES MUST STILL BE INCLUDED LATER IN THE WEEK
HOWEVER AS LESSER WAVES THREATEN PORTIONS OF THE AREA.

BLENDED INITIALIZATION HANDLED THIS RELATIVELY WELL AND FEW MAJOR
CHANGES WERE REQUIRED.

&&

.AVIATION /DISCUSSION FOR THE 07/00Z TAF ISSUANCE/...
ISSUED AT 615 PM EDT FRI MAY 6 2016

GOOD CONFIDENCE THAT FLYING CONDITIONS WILL BE VFR THROUGH THE TAF
PERIOD WITH THE POSSIBLE EXCEPTION OF BRIEF MVFR OR IFR IN
THUNDERSTORMS TOMORROW AFTERNOON AND EVENING. HOWEVER...CONFIDENCE
TOO LOW THAT FAR OUT WITH THE CONVECTIVE NATURE OF IT.
OTHERWISE...SHOULD NOT SEE FOG OVERNIGHT AGAIN LIKE LAST NIGHT AS
WINDS WEST AND SOUTHWEST WINDS SHOULD PICK UP A BIT TO NEAR 10 KNOTS
BY 12Z TOMORROW. WILL START VCTS AFTER 16Z SATURDAY AT LAF AND 18Z
ELSEWHERE AS A COLD FRONT GETS CLOSE. WILL LIKELY HAVE TO ADD TEMPO
MVFR THUNDERSTORM GROUPS AS THE EVENT GETS CLOSER TOMORROW.

WINDS WILL VEER TO CLOSER TO 310 DEGREES AND INCREASE TO 15 KNOTS OR
MORE WITH GUSTS TO 20 KNOTS OR MORE TOMORROW IN THE VICINITY OF THE
FRONT.

&&

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

&&

$$

SYNOPSIS...PUMA
NEAR TERM...PUMA
SHORT TERM...PUMA
LONG TERM...NIELD
AVIATION...MK



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