Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 271355
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
955 AM EDT WED APR 27 2016

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

&&

.SYNOPSIS...
ISSUED AT 347 AM EDT WED APR 27 2016

SHOWERS AND EMBEDDED THUNDERSTORMS WILL ONCE AGAIN INCREASE ACROSS
THE REGION LATER TODAY AND TONIGHT AS A FRONTAL BOUNDARY REMAINS
ACROSS CENTRAL INDIANA. ADDITIONAL STORMS ARE POSSIBLE THURSDAY AS
LOW PRESSURE TRACKS INTO THE AREA. DRY WEATHER IS EXPECTED FRIDAY
BEFORE RAIN AND STORMS RETURN FOR THE WEEKEND AS ANOTHER LOW
PRESSURE SYSTEM TRACKS THROUGH THE OHIO VALLEY.

&&

.NEAR TERM /TODAY/...

ISSUED AT 942 AM EDT WED APR 27 2016

SURFACE ANALYSIS LATE THIS MORNING SHOWS A STATIONARY FRONT
ACROSS KENTUCKY. COOL NORTHEAST FLOW WAS IN PLACE ACROSS CENTRAL
INDIANA WITH TEMPS IN THE 50S. RADAR SHOWS A AREA OF RAIN SHOWERS
WITH ISOLATED THUNDERSTORMS STRETCHING ACROSS SOUTHERN ILLINOIS
INTO CENTRAL KENTUCKY.

WATER VAPOR IMAGERY SHOW AN UPPER SHORT WAVE ACROSS MISSOURI
POISED TO PIVOT INTO THE OHIO VALLEY LATER THIS AFTERNOON. AS THIS
OCCURS...THE FRONTAL SYSTEM TO THE SOUTH WILL ONCE AGAIN MOVE BACK
NORTHWARD INTO CENTRAL INDIANA AND BE A FOCUS FOR PRECIPITATION
DEVELOPMENT LATER THIS AFTERNOON AND EVENING. GIVEN RECENT RADAR
TRENDS...HAVE LOWER POPS FOR THE NEXT 1-2 HOURS...FOCUSING BEST
POPS DURING THE LATE AFTERNOON HOURS. ALSO GIVEN THE CLOUD COVER
AND THE COOL NORTHEAST FLOW ACROSS THE FORECAST AREA...TRENDED
HIGHS COOLER THAN THE PREVIOUS FORECAST...CLOSER TO THE ONGOING
LAV GUIDANCE.

&&

.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
ISSUED AT 347 AM EDT WED APR 27 2016

FORECAST CHALLENGES PRIMARILY FOCUS ON PRECIP CHANCES TONIGHT
THROUGH THURSDAY NIGHT WITH THE FRONTAL BOUNDARY CONTINUING TO
MEANDER ACROSS THE REGION.

SURFACE LOW PRESSURE WILL STEADILY WEAKEN OVER THE MISSOURI VALLEY
TONIGHT WITH A WEAKENING OCCLUDED FRONT PRESSING EAST TO A LOCATION
NEAR THE WABASH RIVE BY DAYBREAK THURSDAY. INSTABILITY AXIS WILL
PERSIST IN THE WARM SECTOR BETWEEN THE WARM FRONT DRAPED ACROSS THE
REGION AND THE APPROACHING OCCLUDED BOUNDARY...WITH RENEWED
CONVECTIVE DEVELOPMENT EXPECTED OVER THE MID MISSISSIPPI VALLEY THIS
EVENING. CONVECTION WILL EXPAND NORTHEAST INTO THE FORECAST AREA
THIS EVENING INTO THE OVERNIGHT...AIDED BY DIFFLUENCE ALOFT AND AN
INCREASE IN MOIST LOW LEVEL FLOW AHEAD OF THE BOUNDARY. THE RESULT
WILL BE THE BEST POTENTIAL FOR WIDESPREAD SHOWERS AND EMBEDDED
THUNDER. WILL CONTINUE WITH CATEGORICAL POPS FOR THE ENTIRE FORECAST
AREA TONIGHT. STORMS SHOULD REMAIN SUBSEVERE THIS EVENING WITH ONLY
POSSIBLE EXCEPTION ACROSS THE LOWER WABASH VALLEY WHERE POTENTIAL
FOR CONVECTION TO BECOME SURFACE BASED AS THE WARM FRONT LIFTS
NORTH. HIGH PRECIP WATER VALUES SUPPORTS RAINFALL AMOUNTS IN EXCESS
OF AN INCH BY THURSDAY MORNING...ESPECIALLY SOUTH OF I-70. COULD SEE
LOCALIZED FLOODING AS MANY OF THESE AREAS RECEIVED AN INCH OR BETTER
ON TUESDAY AFTERNOON AND EVENING.

THE WEAKENED SURFACE WAVE WILL KICK OUT TO THE EAST WITH THE UPPER
ENERGY...TRACKING ACROSS THE LOWER GREAT LAKES THURSDAY NIGHT BEFORE
DEPARTING TO THE EAST. SOUTHERLY FLOW AND MODEST INSTABILITY
DEVELOPING ON THURSDAY WITH THE BOUNDARY LINGERING OVER THE AREA
SUPPORTIVE OF SCATTERED CONVECTION ORGANIZING...ESPECIALLY DURING
PEAK HEATING IN THE AFTERNOON. BRIEF PERIOD OF DECENT BL SHEAR
DURING THE AFTERNOON MAY BE ENOUGH TO SUPPORT A LOW SEVERE WEATHER
RISK OVER EASTERN PORTIONS OF THE FORECAST AREA WITHIN THE UNSTABLE
AIRMASS. WBZERO VALUES BETWEEN 7-8KFT SUGGEST LARGE HAIL WOULD BE A
PRIMARY CONCERN ALONG WITH STRONGER WIND GUSTS AS CORES COLLAPSE.
LACK OF DEEPER MOISTURE MUDDLES THE POTENTIAL SOMEWHAT...BUT THIS
WILL BE SOMETHING TO MONITOR GOING FORWARD.

SHOWERS WILL END THURSDAY NIGHT AS THE LOW DEPARTS OFF TO THE EAST.
ARRIVAL OF WEAK SURFACE HIGH PRESSURE AND A RIDGE ALOFT WILL PROVIDE
DRY PLEASANT WEATHER FOR FRIDAY. MODEL SOUNDINGS ONCE AGAIN SHOW A
LINGERING SHALLOW LAYER OF MOISTURE BENEATH AN INVERSION WHICH
SUGGESTS THE POSSIBILITY OF A STUBBORN LOWER CLOUD DECK TAKING TIME
TO MIX OUT ON FRIDAY. MOISTURE WILL QUICKLY EXPAND INTO THE LOWER
OHIO VALLEY LATE FRIDAY NIGHT AS LOW PRESSURE KICKS OUT INTO THE
SOUTHERN PLAINS. WILL CONTINUE WITH INTRODUCING A LOW CHANCE FOR
SHOWERS IN THE WABASH VALLEY IN THE PREDAWN HOURS SATURDAY BUT WITH
BETTER ISENTROPIC LIFT REMAINING TO THE WEST...EXPECT MOST OF THE
AREA WILL REMAIN DRY THROUGH 12Z SATURDAY.

TEMPS...LOW LEVEL THERMALS SUPPORTED A MOS BLEND FOR HIGHS ON
THURSDAY AS MOST OF THE AREA SHOULD RISE INTO THE 70S. PREFER THE
COOLER MAVMOS GUIDANCE FOR FRIDAY WITH UNCERTAINTY ON LOW CLOUD
DEPARTURE AS DISCUSSED ABOVE. MAVMOS GUIDANCE LOOKED REASONABLE FOR
OVERNIGHT LOWS THROUGH THE PERIOD.

&&

.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 271200Z TAF ISSUANCE/...
ISSUED AT 616 AM EDT WED APR 27 2016

IFR CONDITIONS SHOULD GIVE WAY TO MVFR BY MID MORNING...WITH PERHAPS
A FEW HOURS OF VFR DURING THE AFTERNOON. CONVECTION WILL RETURN LATE
AFTERNOON/EARLY EVENING.

INVERSION WILL KEEP LOW CLOUDS TRAPPED FOR MOST OF THE DAY. THERE
SHOULD BE A GRADUAL INCREASE IN CEILING HEIGHTS AS THE DAY
PROGRESSES. CONFIDENCE IS LOW IN SPECIFIC TIMING OF THE CEILINGS
THOUGH.

A WEAKENING LINE OF CONVECTION MAY MOVE IN AROUND 18Z...BUT
CONFIDENCE IS TOO LOW IN ITS COVERAGE TO MENTION. A BETTER CHANCE OF
CONVECTION WILL OCCUR CLOSER TO 00Z...WHICH SHOULD LAST INTO THE
EVENING HOURS.


&&

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

$$

SYNOPSIS...RYAN
NEAR TERM...TDUD
SHORT TERM...RYAN
LONG TERM...50
AVIATION...50


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