Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 280434
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
1234 AM EDT THU APR 28 2016

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

&&

.SYNOPSIS...
ISSUED AT 217 PM EDT WED APR 27 2016

AN ACTIVE WEATHER PATTERN WILL CONTINUE FOR THE NEXT SEVERAL DAYS.
A WARM FRONT SOUTH OF INDIANA ALONG WITH AN APPROACHING LOW
PRESSURE SYSTEM FROM THE WEST WILL BRING SHOWERS AND
THUNDERSTORMS TO CENTRAL INDIANA TONIGHT. LESSER CHANCES FOR RAIN
WILL CONTINUE THROUGH THURSDAY NIGHT AS THE FRONTAL SYSTEM WILL
REMAIN LINGERING NEAR CENTRAL INDIANA.

WEAK HIGH PRESSURE WILL BUILD ACROSS CENTRAL INDIANA ON
FRIDAY...RESULTING IN THE BEST CHANCES FOR DRY WEATHER THEN. MORE
CHANCES FOR RAIN LOOK IN STORE FOR THE WEEKEND AS YET ANOTHER LOW
PRESSURE SYSTEM IS EXPECTED TO PUSH THROUGH THE OHIO VALLEY.

&&

.NEAR TERM /TONIGHT/...

ISSUED AT 217 PM EDT WED APR 27 2016

SURFACE ANALYSIS EARLY THIS AFTERNOON SHOWS LOW PRESSURE CENTERED
OVER EASTERN NEBRASKA ALONG WITH A WARM FRONT EXTENDING SOUTHEAST
ACROSS NRN MISSOURI...SOUTHERN ILLINOIS TO KENTUCKY. RADAR SHOWS A
BAND OF PRECIP OVER SW CENTRAL INDIANA LIFTING NORTHWARD. WATER
VAPOR IMAGERY SHOWS A SHORT WAVE ACROSS EASTERN MISSOURI AND
WESTERN ILLINOIS...PIVOTING NORTHEAST AROUND A DEEP UPPER LOW OVER
NEBRASKA. COOL NORTHEAST SURFACE FLOW WAS IN PLACE ACROSS
INDIANA...WITH TEMPS MAINLY IN THE 50S.

MANY FAVORABLE INGREDIENTS COMING TOGETHER TONIGHT FOR RAIN. THE
PREVIOUSLY MENTIONED SHORT WAVE AND COLD FRONT ARE EXPECTED TO
LIFT NORTH ACROSS THE FORECAST AREA...PROVIDING GOOD FORCING.
WATER VAPOR SHOW PLENTY OF MOISTURE BEING PULLED NORTH INTO THE
OHIO VALLEY FROM THE DEEP SOUTH. 300K GFS ISENTROPIC SURFACE SHOWS
EXCELLENT LIFT THROUGH THE EVENING WITH SPECIFIC HUMIDITIES OVER
7 G/KG. FORECAST SOUNDINGS SHOW A SATURATED COLUMN THROUGH THE
EVENING HOURS ACROSS CENTRAL INDIANA AS THESE FEATURES PASS. AFTER
06Z...BEST FORCING APPEARS LOST TO THE EAST AND ISENTROPIC LIFT
APPEARS TO BE GONE. TIME HEIGHTS SHOWING DRYING IN THE MIDDLE
LEVELS...WITH LINGERING LOWER LEVEL MOISTURE. THUS CANNOT RULE OUT
A BRIEF SHOWER/SPRINKLE/DRIZZLE AFTER 06Z...BUT MEASURABLE PRECIP
SHOULD BE CONTAINED TO THE AFTERNOON AND EVENING HOURS. GIVEN THIS
WILL TREND TOWARD CATEGORICAL POPS DURING THE AFTERNOON AND EVENING
HOURS...DECREASING TOWARD LOW CHC POPS OVERNIGHT.

GIVEN THE MINIMAL TEMPERATURE ADVECTION AND EXPECTED CLOUDS AND
RAIN...WILL TREND LOWS WARMER THAN MAVMOS.

&&

.SHORT TERM /THURSDAY THROUGH SATURDAY/...

ISSUED AT 217 PM EDT WED APR 27 2016

MODELS SUGGEST AN ACTIVE WEATHER PATTERN TO CONTINUE THROUGH THIS
PERIOD. SURFACE BOUNDARY IS EXPECTED TO BE LINGERING ACROSS THE
FORECAST AREA ON THURSDAY AND THURSDAY NIGHT. MINIMAL FORCING
APPEARS AVAILABLE ON THURSDAY MORNING AS MODELS DEPICT A SHORT
WAVE EXITING THE AREA. HOWEVER BY AFTERNOON...FORECAST SOUNDINGS
SHOW STEEP LAPSE RATES IN PLACE WITH REACHABLE CONVECTIVE TEMPS.
FURTHERMORE...A WEAK LOW PRESSURE SYSTEM APPEARS  TO PUSH EAST
ALONG THE FRONT OVER THE STATE...AGAIN PUSHING THE FRONTAL
BOUNDARY FARTHER SOUTH. WITH MARGINAL FORCING IN PLACE THIS
TIME...WILL CONTINUE TO NEED POPS THROUGH THURSDAY
EVENING...ALBEIT LOW CHC POPS. FRONTAL POSITION WILL BE A KEY
PLAYER IN THURSDAY/S HIGHS/ GIVEN THIS WILL STICK CLOSE TO A BLEND
EXPECT ACROSS THE SOUTHERN PARTS OF THE FORECAST AREA WHERE WARM
AIR ADVECTION AND SW FLOW MAY ALLOW TO GUIDANCE TO BE EXCEEDED.
WILL STICK CLOSE TO A BLEND ON LOWS THURSDAY NIGHT.

FORCING APPEARS LOST ON FRIDAY AND FRIDAY NIGHT AS THE SURFACE
FRONT SINKS FARTHER SOUTH TOWARD KENTUCKY AND HIGH PRESSURE NORTH
OF THE GREAT LAKES PROVIDES COOL NORTHEAST SURFACE FLOW. MEANWHILE
ALOFT...RIDGING BUILDS ACROSS INDIANA WHILE A WEAK RIDGE RIDING
SHORT WAVE LOOKS TO PUSH THROUGH THE TENNESSEE RIVER VALLEY. WITH
FORECAST SOUNDINGS SHOWING MAINLY A DRY COLUMN...WILL TREND TOWARD
A DRY FORECAST. AS FOR TEMPS...LINGERING LOWER LEVEL CLOUDS AND
COOL NORTHEASTERLY FLOW WILL KEEP TEMPS FROM RISING MUCH. A BLEND
OF MAVMOS AND METMOS WILL WORK OK.

MODELS SUGGEST YET ANOTHER LOW PRESSURE SYSTEM SPINNING UP OVER
THE CENTRAL PLAINS ON SATURDAY...PUSHING EAST AND ONCE AGAIN
PULLING THE FRONTAL BOUNDARY BACK NORTH TOWARD INDIANA FOR THE
WEEKEND. FORECAST SOUNDINGS AGAIN BEGIN TRENDING TOWARD A
SATURATED COLUMN AS THESE SIMILAR FEATURES ONCE AGAIN PUSH INTO
THE AREA. BEST TIMING AT THIS POINT APPEARS TO BE DURING THE
AFTERNOON...THUS WILL TRY AND TREND POPS HIGHER DURING THE
AFTERNOON.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
ISSUED AT 230 AM EDT WED APR 27 2016

MODELS ARE SIMILAR...BUT RUN TO RUN CONSISTENCY HAS NOT BEEN THAT
GREAT. THAT LEADS TO A LOWER CONFIDENCE FORECAST...SO JUST ACCEPTED
THE SUPERBLEND INITIALIZATION FOR MOST ITEMS.

AN UPPER LOW WILL MOVE ACROSS THE REGION DURING THE LONG TERM.
LATEST OPERATIONAL RUNS HAVE SPED THINGS UP...BUT ENSEMBLE QPF PLOTS
SHOW MANY MEMBERS HOLDING ONTO RAIN LONGER THAN THE OPERATIONAL
RUNS. THUS WITH THE UNCERTAINTY...AND TO AVOID FLIP-FLOPPING...LEFT
POPS IN THROUGHOUT THE LONG TERM.

TEMPERATURES SHOULD REMAIN NEAR NORMAL THROUGH THE PERIOD.

&&

.AVIATION /DISCUSSION FOR THE 280600Z TAFS/...
ISSUED AT 1234 AM EDT THU APR 28 2016

SCATTERED SHOWERS/ISOLATED THUNDERSTORMS CONTINUE TO LINGER AHEAD OF A
VORTICITY LOBE MOVING THROUGH WESTERN ILLINOIS. APPEARS THERE WILL BE
SHOWER ACTIVITY IN THE VICINITY OF THE TERMINALS THROUGH ABOUT
280900Z AS THIS VORTICITY LOBE MOVES THROUGH. THERE ARE SOME
SCATTERED STORMS CURRENTLY MOVING TOWARD SOME SITES...BUT BY VALID
TIME PERHAPS ONLY KIND WILL SEE THUNDER. WILL WAIT UNTIL ISSUANCE
TIME FOR ANY BRIEF INCLUSION OF THUNDER.

OTHERWISE...CONTINUED WARM/MOIST ADVECTION OVER A FRONTAL ZONE TO
THE SOUTH SHOULD ALLOW FOR A GRADUAL INCREASE OF IFR CEILINGS DURING
THE COURSE OF THE NIGHT. SHOWER ACTIVITY MAY TEND TO KEEP WIDESPREAD
IFR CEILING FROM DEVELOPING UNTIL AFTER 280900Z. EXPECTING IFR
CEILINGS TO LINGER INTO THE MIDDAY HOURS OF THURSDAY...WITH CEILING
LIFTING ABOVE IFR BY THEN AS A COLD FRONT MOVES THROUGH.

SURFACE WINDS 090-120 DEGREES AT 7-10 KTS OVERNIGHT EXPECTED TO
DIMINISH WITH TIME AS THE FRONTAL ZONE APPROACHES. WINDS SHOULD
BECOME 240-270 DEGREES AT 8-11 KTS BY LATE MORNING THURSDAY WITH THE
PASSAGE OF A COLD FRONT.

&&

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

$$

SYNOPSIS...PUMA
NEAR TERM...PUMA
SHORT TERM...PUMA
LONG TERM...50
AVIATION...JAS/50



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