Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 301650
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
1250 PM EDT SAT MAY 30 2015

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

&&

.SYNOPSIS...
ISSUED AT 217 AM EDT SAT MAY 30 2015

AN UPPER LEVEL WEATHER DISTURBANCE ARRIVING FROM THE SOUTHERN
PLAINS ALONG WITH A COLD FRONT PUSHING THROUGH THE OHIO VALLEY
WILL RESULT IN CHANCES FOR RAIN SHOWERS AND THUNDERSTORMS
TODAY...PARTICULARLY THIS AFTERNOON AND TONIGHT.

A FEW SHOWERS WILL LINGER ON SUNDAY MORNING AS THE LOW DEPARTS TO
THE EAST. BY SUNDAY AFTERNOON...COOLER NORTHERLY FLOW ASSOCIATED
WITH HIGH PRESSURE IN THE WAKE OF THE LOW WILL BRING A RETURN OF
DRY WEATHER...BUT COOLER TEMPERATURES.

HIGH PRESSURE IS THEN SET TO REMAIN ACROSS THE AREA THROUGH THE
MIDDLE OF NEXT WEEK...BRINGING DRY AND COOLER WEATHER.

&&

.NEAR TERM /TODAY/...

ISSUED AT 1015 AM EDT SAT MAY 30 2015

UPDATED THE HWO AND WEATHER STORY FOR THE SPC DAY1 SLIGHT RISK AND
WPC DAY1 EXCESSIVE RAINFALL GRAPHIC. FLASH FLOOD GUIDANCE IS IN
EXCESS OF 3 INCHES OVER NORTHWESTERN PARTS OF CENTRAL
INDIANA...WHERE THE MOST RAINFALL IS EXPECTED. THUS...DO NOT EXPECT
WIDESPREAD FLOODING...AND THUS DO NOT FEEL LIKE A FLOOD WATCH IS
NEEDED AT THIS TIME.

PREVIOUS DISCUSSION FOLLOWS...

ISSUED AT 217 AM EDT SAT MAY 30 2015

SURFACE ANALYSIS EARLY THIS MORNING SHOWS A BROAD TROUGH OF LOW
PRESSURE STRETCHING FROM THE GREAT LAKES...ACROSS ILLINOIS TO THE
SOUTHERN PLAINS. WARM AND MOIST SOUTHERLY FLOW REMAINED IN PLACE
ACROSS CENTRAL INDIANA AHEAD OF THE TROUGH. DEW POINTS WERE
HOLDING IN THE MOIST MIDDLE 60S. WATER VAPOR IMAGERY SHOWED A
SHORT WAVE ACROSS MISSOURI AND ARKANSAS PUSHING NORTHEAST. RADAR
SHOWS SOME SCT CONVECTION ACROSS ILLINOIS AND MISSOURI...ALBEIT IT
WAS ONLY GARDEN VARIETY SHOWERS AND STORMS.

MAIN FORECAST CHALLENGE TODAY WILL BE POPS. FORECAST SOUNDINGS AND
TIME HEIGHTS SHOW DEEP SATURATION ARRIVING BY LATE AFTERNOON. GFS
AND NAM SHOW STRONG FORCING ARRIVING FROM THE SOUTHWEST ALOFT
AFTER 18Z...TIMING WELL WITH DAYTIME HEATING. FORECAST SOUNDINGS
SHOWING AROUND 100 J/KG OF CAPE THIS AFTERNOON WITH PRECIPITABLE
WATER OVER 1.75 INCHES. LOWER LEVEL Q VECTORS SHOW BEST
CONVERGENCE ACROSS CENTRAL AND NORTHERN INDIANA...MAINLY LATE IN
THE DAY AND EARLY THIS EVENING. GIVEN ALL OF THE AVAILABLE
FORCING AND MOISTURE...WILL TREND POPS AT OR ABOVE MAVMOS IN MOST
CASES. AS THE BEST FORCING FAILS TO ARRIVE UNTIL THE
AFTERNOON...WILL TRY AND RAMP UP POPS AS THE DAY PROGRESSES...WITH
THE MOST DRY HOURS ACROSS THE EASTERN PARTS OF THE FORECAST AREA.

AS FOR TEMPS...WILL ONCE AGAIN TREND TOWARD
PERSISTENCE...ESPECIALLY IN THE EAST WHERE PRECIPITATION SHOULD
HOLD OFF THE LONGEST.

&&

.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...

ISSUED AT 217 AM EDT SAT MAY 30 2015

WET WEATHER LOOKS IN STORE FOR TONIGHT AS THE PREVIOUSLY
MENTIONED UPPER SHORT WAVE WILL BE PUSHING ACROSS INDIANA
OVERNIGHT. GFS AND NAM ALSO SUGGEST THE SURFACE LOW WILL TRACK
ACROSS CENTRAL INDIANA...A BIT FARTHER NORTH THAN PREVIOUS
RUNS...WHICH MAY RESULT IN THE HEAVIER AMOUNTS OF RAIN BEING
FOCUSED ACROSS THE NORTHERN PARTS OF CENTRAL INDIANA. STILL ALL
AREA SHOULD GET SOME PRECIP THIS EVENING AS THIS SYSTEM PASSES.
VERY GOOD LOWER LEVEL CONVERGENCE REMAINS ACROSS THE AREA AS THIS
SYSTEM PASSES. TIME HEIGHTS ALSO SHOW BEST FORCING AT 00Z THROUGH
ABOUT 06Z AS FORCING ALOFT PASSES. FORECAST SOUNDINGS SHOW DEEP
SATURATION. THUS WILL TREND TOWARD 100 POPS FOR MOST AREAS. ALONG
WITH TEMPS WARMER THAN MAVMOS GIVEN THE EXPECTED CLOUDS AND RAIN.

TIME HEIGHT SECTIONS SHOW FORCING ENDING QUICKLY ON SUNDAY
MORNING AS THE THE GFS AND NAM DEPICT THE SHORT WAVE ALOFT EXITING
QUICKLY. SOME TIME HEIGHTS CONTINUE TO SHOW SATURATED LOWER LEVELS
AND FORECAST SOUNDINGS SHOW A LAYER OF LOWER LEVEL CLOUD LINGERING
THROUGH THE DAY WITH DRY AIR ALOFT. MEANWHILE AT THE SURFACE...LOW
PRESSURE IS EXPECTED TO EXIT INDIANA AND PUSH TOWARD NORTHEAST
OHIO...KEEPING WEAK CYCLONIC FLOW IN PLACE ACROSS THE AREA ALONG
WITH COLD AIR ADVECTION. GIVEN THE LOSS OF FORCING...HEAVIER RAINS
SHOULD END ON SUNDAY RATHER QUICKLY...BUT GIVEN THE CYCLONIC FLOW
AND LOWER LEVEL CLOUDS...A FEW VERY LIGHT SHOWERS OR DRIZZLE
CANNOT BE RULED OUT. WILL TREND POPS AT OR BELOW
MAVMOS...ESPECIALLY ACROSS THE WEST WHERE FORCING IS LOST THE
SOONEST. AS FOR TEMPS WILL TREND AT OR BELOW MAVMOS GIVEN THE
EXPECTED CLOUD AND COOL NORTH WINDS.

ON SUNDAY NIGHT INTO MONDAY...THE GFS AND NAM SUGGESTS DRY...NW FLOW
IN PLACE ALOFT. MEANWHILE AT THE SURFACE...A LARGE AREA OF HIGH
PRESSURE IN THE WAKE OF THE DEPARTING LOW WILL BE PLACE ACROSS
THE GREAT LAKES...PROVIDING A COOL NORTHEAST FLOW OF DRY
CONTINENTAL FLOW TO INDIANA. FORECAST SOUNDINGS SHOW A DRY COLUMN
IN PLACE ON SUNDAY NIGHT THROUGH MONDAY. MEANWHILE...GOOD
SUBSIDENCE IS SEEN IN THE MIDDLE LEVELS. THUS WILL TREND TOWARD AS
DRY FORECAST DURING THIS PERIOD. AS FOR TEMPS...GIVEN THE COOL
NORTHEAST FLOW...A BLEND OF THE MAVMOS AND METMOS SHOULD WORK NICELY.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
ISSUED AT 229 AM EDT SAT MAY 30 2015

ENSEMBLES IN GOOD AGREEMENT EARLY IN THE EXTENDED IN DEVELOPING A
CUTOFF LOW OVER THE GULF COAST STATES...WITH RIDING BUILDING OVER
THE TOP OF THE CUTOFF ACROSS THE OHIO VALLEY. BY LATE NEXT
WEEK...THERE ARE SOME DIFFERENCES AS TO THE EVENTUAL TRACK OF THIS
CUTOFF. MOST OF THE ENSEMBLES DRIFT THIS CUTOFF SLOWLY EAST INTO THE
SOUTHEAST PARTS OF THE COUNTRY...WHILE A FEW MEMBERS LIFT THIS
FEATURE NORTH INTO THE OHIO VALLEY BY NEXT FRIDAY.

THERE SHOULD BE LITTLE THREAT FOR PRECIPITATION FOR MOST OF THIS
PERIOD AS UPPER RIDGE BUILDS OVERHEAD. WILL GO WITH A DRY FORECAST
FROM TUESDAY THROUGH THURSDAY. WILL KEEP CHANCE POPS IN THE FORECAST
FOR NEXT FRIDAY TO COVER THE POSSIBILITY OF THE NORTHWARD TRACK OF
THE UPPER LOW. A POTENTIAL SHORT WAVE MOVING OVER THE UPPER GREAT
LAKES LATE NEXT WEEK MAY ALSO ENHANCE POPS BY NEXT FRIDAY.

&&

.AVIATION /DISCUSSION FOR 301800Z TAF ISSUANCE/...

ISSUED AT 1249 PM EDT SAT MAY 30 2015

SCATTERED THUNDERSTORMS CAN BE EXPECTED AT THE SITES OFF AND ON
THROUGH THE AFTERNOON/EVENING HOURS. OUTSIDE OF STORMS MAINLY VFR
CONDITIONS...WITH IFR OR LOWER AT TIMES IN THE STORMS. CHANCES FOR
SHOWERS AND STORMS WILL CONTINUE UNTIL AFTER THE SYSTEM MOVES
THROUGH DURING THE OVERNIGHT HOURS. HIGH CONFIDENCE ON SCATTERED
COVERAGE OF THUNDERSTORMS DURING THE NEXT 6 HOURS...WITH LESSER
CONFIDENCE THAT THERE WILL STILL BE THUNDER LATER TONIGHT AND NOT
JUST RAIN. WITH THE SURFACE LOW MOVING OVER THE SITES OVERNIGHT ALSO
EXPECT TO SEE CEILINGS DROP AND COULD HAVE SOME VISIBILITY ISSUES AS
WELL. LOW CEILINGS LIKELY TO PERSIST THROUGH AT LEAST MIDDAY SUNDAY.

&&

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

$$

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

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