Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 221646
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
1246 PM EDT TUE JUL 22 2014

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

&&

.SYNOPSIS...
ISSUED AT 204 AM EDT TUE JUL 22 2014

A WARM...SUMMER DAY IS EXPECTED TODAY AS HIGH PRESSURE EAST OF
INDIANA PROVIDES WARM AND HUMID SOUTHERLY FLOW TO CENTRAL INDIANA.
THIS WILL RESULT IN A TYPICAL SUMMER DAY. TONIGHT A QUICK MOVING
COLD FRONT WILL PUSH CENTRAL INDIANA FROM THE NORTHWEST. THIS WILL
RESULT IN CHANCES FOR LIGHT SHOWERS OR AN ISOLATED THUNDERSTORM
TONIGHT.

THE COLD FRONT WILL PUSH SOUTH OF CENTRAL INDIANA ON
THURSDAY...ALLOWING HIGH PRESSURE TO RETURN TO CENTRAL INDIANA
FROM THE UPPER MIDWEST. THE HIGH WILL BRING A RETURN TO COOLER
THAN NORMAL TEMPERATURES AND DRY CONDITIONS FOR THE REST OF THE
WORK WEEK.

ANOTHER FRONTAL SYSTEM WILL BRING MORE CHANCES FOR RAIN DURING
THE WEEKEND.

&&

.NEAR TERM /UPDATED DISCUSSION FOR TODAY/...

ISSUED AT 936 AM EDT TUE JUL 22 2014

ONLY MINOR CHANGES TO FIRST FEW HOURS BUT REMAINING PORTION OF THE
DAY APPEARS ON TRACK. WILL HAVE TO MONITOR INDY TEMPS TO SEE IF
WE MIGHT NOT SQUEAK OUT A MAX TEMP ABOVE 87F WE CURRENTLY PROJECT.

&&

.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...

ISSUED AT 204 AM EDT TUE JUL 22 2014

MAIN CHALLENGE DURING THIS PERIOD WILL BE THE COLD FRONT PASSAGE
EXPECTED TONIGHT.

NAM AND GFS CONTINUE TO KEEP A STRONG RIDGE IN PLACE ACROSS THE
WESTERN UNITED STATES. THIS IN TURN RESULTS IN A CONTINUED LEE
SIDE FLOW FROM THE NORTHWEST SPILLING INTO THE GREAT LAKES AND
INDIANA. TONIGHT...THE GFS AND NAM SUGGEST A SHORT WAVES SLIDES
DOWN THE FROM THE MIDWEST...WITH THE BEST DYNAMICS A FORCING
FLOWING ACROSS THE GREAT LAKES AND MICHIGAN. AN ASSOCIATED COLD
FRONT IS EXPECTED TO ACCOMPANY THIS FEATURE AND PASS ACROSS
INDIANA...MAINLY OVERNIGHT. ESSENTIALLY THE TAIL OF THIS COLD
FRONT IS WHAT IS LEFT AS IT PASSES ACROSS INDIANA...PROVIDING VERY
LIMITED FORCING. FORECAST SOUNDINGS AND TIME HEIGHT SECTIONS FAIL
TO SHOW DEEP SATURATION OVERNIGHT. GFS 310K ISENTROPIC SURFACE
SHOWS AN AXIS OF HIGH SPECIFIC HUMIDITIES PUSHING ACROSS THE
STATE...OVER 9 G/KG. HOWEVER NO UPGLIDE IS PRESENT. LOWER LEVEL Q
VECTOR CONVERGENCE IS VERY GOOD ACROSS CENTRAL INDIANA AS THE
FRONT PASSES TONIGHT. HOWEVER...LLJ REMAINS WEAK...WITH SPEEDS
AROUND 20-25 KNTS THROUGH THE NIGHT. THUS CONFIDENCE IS LOW FOR A
SOAKING RAIN...ALTHOUGH A FEW LIGHT SHOWERS CANNOT BE RULED OUT.
WILL USE SOME LOW CHANCE POPS OVERNIGHT. GIVEN AT LEAST THE
EXPECTED CLOUD COVER WILL TREND LOW TEMPS WARMER THAN MAVMOS.

GOOD COLD AIR ADVECTION AND SUBSIDENCE THEN TAKE PLACE ACROSS THE
AREA ON WEDNESDAY AS FORECAST SOUNDING SHOW A DRY COLUMN. SURFACE
HIGH PRESSURE BUILDS INTO CENTRAL INDIANA...DIVING SOUTHEAST OUT
OF SOUTH CENTRAL CANADA...BRINGING A COOLER AND DRY CONTINENTAL
AIR MASS TO OUR REGION. THIS WILL RESULT IN DRY AND COOLER WEATHER
THROUGH THURSDAY NIGHT AT LEAST. FORECAST SOUNDINGS ON THURSDAY
SUGGEST ATTAINABLE CONVECTIVE TEMPERATURES WITH A MID LEVEL
INVERSION...ONCE AGAIN SUGGEST SOME HARMLESS...LOW-TOPPED FLAT CU
DURING THE AFTERNOON HOURS. GIVEN THE GOOD COLD AIR ADVECTION IN
PLACE ON WEDNESDAY AND WEDNESDAY NIGHT WILL TREND HIGHS AND LOWS
COOLER THAN MAVMOS. NORTHERLY SURFACE SLOW CONTINUES THROUGH
THURSDAY NIGHT. GIVEN THIS PATTERN WILL WORK A BLEND OF THE MAVMOS
AND METMOS.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...

ISSUED AT 258 AM EDT TUE JUL 22 2014

MODELS ARE CLOSE ENOUGH THAT THE ALLBLEND INITIALIZATION WAS
ACCEPTED FOR MOST PARAMETERS.

FRIDAY LOOKS TO REMAIN DRY. A FRONT WILL MOVE INTO THE AREA AND
STALL OUT THIS WEEKEND. AREAS OF LOW PRESSURE WILL MOVE ALONG THE
FRONT. THIS WILL KEEP THE THREAT FOR SHOWERS AND THUNDERSTORMS IN
THE FORECAST FOR FRIDAY NIGHT THROUGH SUNDAY NIGHT.

CONFIDENCE IN WHICH PERIOD WILL HAVE THE BEST THREAT FOR RAIN IS LOW
SINCE TIMING OF THE WAVES OF LOW PRESSURE IS UNCERTAIN THAT FAR OUT.
WILL KEEP ALLBLEND/S CHANCE POPS.

FOR MONDAY AN UPPER TROUGH WILL DIG INTO THE AREA AND BRING ANOTHER
COLD FRONT. THIS WILL ALSO BRING CHANCES FOR RAIN TO THE AREA.

TEMPERATURES WILL AVERAGE NEAR TO BELOW NORMAL THROUGH THE
PERIOD...WITH THE COOLEST READINGS COMING MONDAY AS THE UPPER TROUGH
MOVES IN.

&&

.AVIATION /DISCUSSION FOR 221800Z TAFS/...

ISSUED AT 1245 PM EDT TUE JUL 22 2014

THUNDERSTORMS ARE POSSIBLE BEGINNING LATE TONIGHT AS A WEAK FRONT
PASSES. THERE IS MAJOR UNCERTAINTY IN HOW WIDESPREAD THEY WILL BE.
THE LATEST MODEL RUNS INDICATE STORMS WILL BE COMMON ENOUGH IN THE
NORTH TO CALL FOR VCTS AT KLAF. TO THE SOUTH THE PROSPECTS FOR
THUNDER ARE MORE UNCERTAIN AND IT IS TOO EARLY TO MENTION ANYTHING
IN THE TAFS. THIS MAY CHANGE WITH UPDATES.

MVFR CEILINGS AND VISIBILITIES WILL BE POSSIBLE AS THE FRONT PASSES.
THESE ARE UNCERTAIN AND IF THEY DO OCCUR WILL BE OF SHORT DURATION.
IT IS PREMATURE TO SQUEEZE THEM INTO THE TAFS.

OTHERWISE...SCATTERED CUMULUS AROUND 5 THOUSAND FEET THIS AFTERNOON
WILL BE REPLACED BY MID LEVEL CLOUDS THIS EVENING.  THESE IN TURN
WILL BE REPLACED BY CEILINGS AROUND 35 HUNDRED FEET LATE TONIGHT.
WINDS ARE FORECAST TO STAY BELOW 10 KNOTS AS THEY VEER FROM
SOUTHWEST TODAY...TO WEST TONIGHT...AND THEN TO NORTH OR NORTHWEST
TOMORROW.

&&

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

$$

SYNOPSIS...PUMA
NEAR TERM...TUCEK
SHORT TERM...PUMA
LONG TERM....50
AVIATION...JK

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