Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 011428
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
1028 AM EDT WED OCT 1 2014

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

&&

.SYNOPSIS...
ISSUED AT 242 AM EDT WED OCT 1 2014

QUIET WEATHER IS EXPECTED TODAY BEFORE A FEW ACTIVE WEATHER DAYS
CONCLUDE THE WORK WEEK.

HIGH PRESSURE OVER THE GREAT LAKES IS EXPECTED TO DEPART TO THE
EAST TODAY...PROVIDING ONE LAST DAY OF QUITE PLEASANT WEATHER. A
WARM FRONT AHEAD OF AN AREA OF LOW PRESSURE WILL ARRIVE IN CENTRAL
INDIANA ON THURSDAY MORNING...AND MAY BRING A FEW SHOWERS TO THE
AREA ON THURSDAY MORNING. IN THE WAKE OF WARM FRONT...WARM
SOUTHERLY WINDS WILL PUSH A VERY WARM AND MORE HUMID AIR MASS INTO
CENTRAL INDIANA BY THURSDAY AFTERNOON.

AS LOW PRESSURE THEN PUSHES NORTH OF INDIANA ON THURSDAY NIGHT AND
FRIDAY...THE LOW WILL DRAG A COLD FRONT ACROSS INDIANA. THIS WILL
RESULT IN SOME SHOWERS AND PERHAPS A FEW THUNDERSTORMS.

IN THE WAKE OF THE COLD FRONT...MUCH COLDER AIR WILL ARRIVE IN
CENTRAL INDIANA FOR THE WEEKEND...PUSHING TEMPERATURES TO BELOW
SEASONAL NORMALS.

&&

.NEAR TERM /TODAY/...

ISSUED AT 242 AM EDT WED OCT 1 2014

SURFACE ANALYSIS EARLY THIS MORNING SHOWS HIGH PRESSURE IN PLACE
OVER THE GREAT LAKES. LOW PRESSURE WAS FOUND OVER THE UPPER
MIDWEST. SKIES WERE MOSTLY CLEAR ACROSS CENTRAL INDIANA AND DEW
POINTS WERE IN THE COMFORTABLE MIDDLE TO LOWER 40S. TEMPERATURES
RANGED FROM THE LOW 40S ACROSS THE NORTHEAST...43 IN MUNCIE AT
THIS TIME!...TO THE UPPER 50S SOUTHWEST. WATER VAPOR SHOWED A
RIDGE OF HIGH PRESSURE ALOFT OVER THE GREAT LAKES WITH SUBSIDENCE
IN PLACE OVER INDIANA.

GFS AND NAM CONTINUE TO SUGGEST THAT THE HIGH PRESSURE SYSTEM AND
RIDGE ALOFT WILL SLOWLY MOVE EAST TODAY AND BEGIN TO EXIT THE
AREA. FORECAST SOUNDINGS AND TIME HEIGHT SECTIONS REMAIN QUITE
DRY. FORECAST SOUNDINGS SHOW CONVECTIVE TEMPERATURES IN THE LOWER
80S TODAY...SOME SO ISOLATED CU CANNOT BE RULED OUT...PARTICULARLY
ACROSS THE SOUTH. THUS WILL AIM FOR A MOSTLY SUNNY DAY.

AS FOR TEMPS...WEAK WARM AIR ADVECTION IS EXPECTED AS THICKNESSES
RISE SLIGHTLY ALONG WITH 850MB TEMPS. SURFACE FLOW ALSO BEGINS A
MORE SOUTHEASTERLY COMPONENT. THUS WILL TREND HIGHS SLIGHTLY
WARMER THAN PERSISTENCE WHICH WILL BE A GOOD BLEND BETWEEN THE
MAVMOS AND METMOS. METMOS IS NOTABLY TOO COLD ACROSS THE EAST
AND NORTHEAST.

&&

.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...

ISSUED AT 242 AM EDT WED OCT 1 2014

ACTIVE WEATHER PATTERN BEGINS TONIGHT AS THE GFS AND NAM SUGGEST A
WARM FRONT ARRIVING TOWARD 12Z THURSDAY. TIME HEIGHTS AND FORECAST
SOUNDINGS SHOW SATURATION BEGINNING IN THE LOWER LEVELS LATE
TONIGHT AMID WEAK LIFT. 305K GFS ISENTROPIC SURFACE SHOWS A SURGE
OF SPECIFIC HUMIDITIES OVER 7 G/KG WITH GOOD LIFT. LOWER LEVEL Q
VECTORS ARE A BIT MORE MARGINAL...SHOWING BEST CONVERGENCE FARTHER
WEST. UPPER SUPPORT APPEARS MARGINAL AS A WEAK WAVE APPEARS TO BE
EJECTED OUT OF THE BROADER...DEEPER SHORT WAVE TO THE WEST. THUS
WILL KEEP THE FORECAST DRY DURING T HE EVENING HOURS AND KEEP A
LOW CHC POPS FOR A SHOWER TOWARD 12Z DUE TO LOWER LEVEL MOISTURE
AND POSSIBLE ISENTROPIC LIFT. AS FOR TEMPS WILL TREND LOWS WARMER
THAN MAVMOS GIVEN THE WARM AIR ADVECTION AND SOUTHERLY FLOW.

GFS AND NAM SUGGEST THAT INDIANA WILL BE FIRMLY IN TH WARM SECTOR
ON THURSDAY...AND AFTER ANY MORNING CLOUDS AND ISOLATED SHOWERS
DEPART SOME GOOD HEATING SHOULD OCCUR AS WARM AIR IS ADVECTED
INTO THE AREA ON SOUTHERLY WINDS. GFS 305 ISENTROPIC SURFACE SHOWS
GOOD MOISTURE PUSHING THROUGH THE AREA OVER THE COURSE OF THE DAY
AND FORECAST SOUNDINGS SHOW SATURATION ALOFT. THUS WILL STICK
CLOSE TO THE MAVMOS POPS AS LINGERING PRECIP WILL BE POSSIBLE IN
THE MORNING AND AN AFTERNOON SHOWERS AMID THE WARM AND HUMID AIR
MASS CANNOT BE RULED OUT. GIVEN THE WARM AIR ADVECTION..BUT
EXPECTED CLOUDS AND POSSIBLE PRECIP WILL TREND HIGHS COOLER THAN
MAVMOS. STILL MID 80S ACROSS MUCH OF CENTRAL INDIANA LOOKS REASONABLE.

MODELS AGREE THAT THE STRONG COLD FRONT WILL PUSH ACROSS THE
FORECAST AREA LATE THURSDAY NIGHT AND EARLY ON FRIDAY. STRONG
FORCING WILL BE PLACE ALOFT AS THE MODELS SUGGEST A DEEP TROUGH
WILL BE PUSHING OUT OF THE CENTRAL PLAINS TOWARD THE OHIO VALLEY.
PLENTY OF MOISTURE LOOKS TO REMAIN IN PLACE DUE TO THE WARM AND
SOUTHERLY FLOW AHEAD OF THE SYSTEM. 305K ISENTROPIC SURFACE SHOWS
SPECIFIC HUMIDITIES IN EXCESS OF 6 G/KG. BY 12Z FRIDAY...FORECAST
SOUNDINGS SHOW DEEP SATURATION WITH PWATS OVER 1.50 INCHES. THUS
WILL WILL TREND POPS HIGHER ON THURSDAY NIGHT AND FRIDAY AS ALL OF
THESE FEATURES PASS THROUGH. GIVEN THE EXPECTED CLOUDS...RAIN AND
COLD AIR ADVECTION WILL EXPECT STEADY OR SLOWLY FALLING
TEMPERATURES THROUGH THE COURSE OF THE DAY ON FRIDAY.

ON FRIDAY NIGHT...MUCH DRYER AIR ARRIVES ALOFT AS THE COLD FRONT
PASSES AND STRONG COLD AIR ADVECTION WILL BE IN PLACE THE
DEEPENING LOW OVER THE GREAT LAKES A STRONG PRESSURE GRADIENT
LOOKS TO BE IN PLACE RESULTING IN GUSTY WEST WINDS AS 850MB TEMPS
FALL TO BELOW 0C BY 12Z SAT. ALOFT STRONG FORCING REMAINS IN PLACE
AS A DEEP UPPER TROUGH PUSHES INTO THE OHIO VALLEY. MOISTURE WILL
REMAIN APROBLEM...HOWEVER...CANNOT RULE OUT ANY WRAP AROUND
PRECIP AT THIS POINT GIVEN THE STRONG DYNAMICS. THUS WILL STICK TO
LOW CHC POPS. WILL TREND LOWS AT OR BELOW MEXMOS LOWS.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...

ISSUED AT 242 AM EDT WED OCT 1 2014

ENSEMBLES INDICATE THAT A DEEP PROGRESSIVE UPPER TROUGH WILL BE
PASSING OFF TO THE EAST AT THE BEGINNING OF THE EXTENDED. COULD BE
SOME LIGHT INSTABILITY SHOWERS OR SPRINKLES ON SATURDAY WITH 850MB
TEMPERATURES PROGGED TO BE NEAR OR BELOW FREEZING. HOWEVER...GIVEN
THE LOCAL AREA WILL BE UNDER THE SUBSIDENCE REGION OF THE UPPER
TROUGH...THINK THE THREAT FOR MEASURABLE PRECIPITATION IS STILL TOO
LOW TO MENTION AT THIS POINT. WILL KEEP SATURDAY DRY FOR NOW.

OTHERWISE...ENSEMBLES SUGGEST ANOTHER UPPER DISTURBANCE WILL DROP
INTO THE AREA AROUND SUNDAY AND MONDAY. WILL GO WITH CHANCE POPS AT
THOSE TIMES. LONG RANGE OPERATIONAL MODELS SUGGEST SOME CONVECTIVE
POTENTIAL WITH THIS SYSTEM.

BY NEXT TUESDAY...UPPER FLOW MAY TEND TO FLATTEN OUT AS HEIGHTS
BEGIN TO RISE. WILL GO DRY FOR NEXT TUESDAY.

&&

.AVIATION /DISCUSSION FOR THE 011200Z TAFS/...

ISSUED AT 1026 AM EDT WED OCT 1 2014

1425Z UPDATE...NO CHANGES NEEDED AT THIS TIME. PREVIOUS
DISCUSSION FOLLOWS.

AREA OF LOW CEILINGS 004-007 AGL HAS BEEN STEADILY PROGRESSING
WEST...CURRENTLY MOVING INTO EAST CENTRAL INDIANA. SHORT TERM MODELS
SUGGEST THE WESTERN EDGE OF THESE CEILINGS MAY GET CLOSE TO KLAF/KIND
AROUND 011200Z-011300Z BEFORE DISSIPATING BY LATE MORNING. AT THIS
TIME...CONFIDENCE IS NOT HIGH ENOUGH TO INCLUDE IN THE
FORECAST...BUT WILL MAKE A LAST MINUTE DECISION AT ISSUANCE TIME.

OTHERWISE...A LIGHT WIND HAS PREVENTED RADIATIONAL FOG FROM FORMING.
MAY SEE SOME BRIEF VISIBILITY RESTRICTIONS AROUND SUNRISE...BUT
DON/T THINK ANYTHING WILL BE TOO WIDESPREAD. SOME LIMITED DIURNAL
CLOUD BASED 030-040 MAY DEVELOP BY EARLY AFTERNOON...ESPECIALLY OVER
THE MORE SOUTHERN TAF SITES. LIGHT SURFACE WINDS BECOMING 090-110
6-8 KTS BY MIDDAY.

&&

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

$$

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

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