Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 011707
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
107 PM EDT TUE SEP 1 2015

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

&&

.SYNOPSIS...
ISSUED AT 400 AM EDT TUE SEP 1 2015

A BROAD UPPER RIDGE OVER THE CENTRAL AND EASTERN U.S. WILL STRENGTHEN
NEXT SEVERAL DAYS AND THEN FLATTEN OUT SOME EARLY NEXT WEEK. EVEN
THOUGH HIGH PRESSURE SURFACE AND ALOFT COVERS MUCH OF THE REGION AN
UPPER DISTURBANCE OVER NORTH CENTRAL INDIANA MAY PRODUCE A CHANCE OF
THUNDERSTORMS LATER TODAY AND ACROSS FAR NORTHEAST SECTIONS TONIGHT AND
WEDNESDAY.  ANOTHER UPPER LEVEL DISTURBANCE MAY PRODUCE A FEW THUNDERSTORMS
NORTH AND CENTRAL SECTIONS THURSDAY AND MOST AREAS NEXT MONDAY.

OTHERWISE...IT WILL BE MOSTLY DRY WITH ABOVE NORMAL TEMPERATURES THROUGH THE
UPCOMING WEEK.

&&

.NEAR TERM /REST OF TODAY/...

ISSUED AT 931 AM EDT TUE SEP 1 2015

1330Z UPDATE...LATEST UPDATE OF THE HRRR SHOWS THE SHOWERS AND
THUNDERSTORMS CURRENTLY OVER EASTERN ILLINOIS SLOWLY MOVING
EASTWARD AND INTO THE WESTERN COUNTIES OF CENTRAL INDIANA OVER THE
NEXT FEW HOURS. HAVE SOME DOUBTS AS TO WHETHER THAT MUCH
PRECIPITATION COVERAGE WILL MOVE THIS FAST INTO THE AREA SINCE THE
UPPER LOW WILL REMAIN FAIRLY STATIONARY THROUGH AT LEAST 00Z.

NEVERTHELESS...UPDATED POPS MAINLY ACROSS THE WEST TO INCREASE
POPS SLIGHTLY BASED ON THE LATEST RADAR TRENDS AND THE HRRR
ANALYSIS. MADE A FEW OTHER MINOR TWEAK TO OTHER WEATHER ELEMENTS
FOR THE REST OF TODAY BASED ON THE LATEST TRENDS. MORE HUMID
CONDITIONS WITH HIGHS IN THE MID TO UPPER 80S WILL PREVAIL ACROSS
THE FORECAST AREA FOR THIS AFTERNOON. PREVIOUS DISCUSSION FOLLOWS.

WATER VAPOR SATELLITE INDICATED A SMALL CLOSED UPPER LOW WAS
LOCATED BETWEEN INDIANAPOLIS AND LAFAYETTE. MOST MODELS INDICATE
MORE CONVECTION DEVELOPING LATER TODAY...HOWEVER THE RAPID REFRESH
INDICATES CONVECTION RAPIDLY DEVELOPING OVER WESTERN SECTIONS OF
CENTRAL INDIANA IN THE NEXT FEW HOURS. I HAVE NOT SEEN ANY
EVIDENCE OF THIS HAPPENING SO FAR AND WILL KEEP EVERYTHING DRY
THROUGH 12Z.

HOWEVER THE COMBINATION OF THE THIS CLOSED UPPER LOW AND DAY TIME HEATING WILL
CAUSE SCATTERED THUNDERSTORMS LATER TODAY.  AS A RESULT WILL GO WITH CHANCE POPS
MOST AREAS TODAY AND SLIGHT CHANCE POPS ACROSS OUR SOUTHWEST.

WITH MORE CLOUDS LATER TODAY...TEMPERATURES SHOULD BE A DEGREE OR TWO COOLER THAN
WHAT THEY WERE YESTERDAY.  WENT WITH HIGHS IN THE MIDDLE 80S OVER NORTHERN SECTIONS
AND THE UPPER 80S ACROSS OUR SOUTH.

&&

.SHORT TERM /TUESDAY THROUGH THURSDAY/...
ISSUED AT 400 AM EDT TUE SEP 1 2015

MODELS DRIFT THIS UPPER DISTURBANCE EAST INTO OHIO TONIGHT AND
WEDNESDAY.  THE NAM INDICATES QUITE A BIT OF CONVECTION ACROSS OUR NORTH
WHILE THE GFS SHOWS LITTLE.  WITH LOSS OF DAYTIME HEATING...I DO NOT
EXPECT MUCH CONVECTION.  BUT WILL MENTION SLIGHT CHANCE POPS ACROSS
OUR NORTH AND EAST CENTRAL SECTIONS TONIGHT.

MODELS INDICATE SOME CONVECTION MAINLY OHIO WEDNESDAY AND WILL CONTINUE
SLIGHT CHANCE POPS FAR NORTHEAST.  OTHERWISE...THE BROAD UPPER RIDGE
SHOULD KEEP IT QUITE WARM AND DRY OVER THE REST OF THE REGION WEDNESDAY
AND WEDNESDAY NIGHT.

ANOTHER WEAK DISTURBANCE MAY PRODUCE A FEW THUNDERSTORMS OVER NORTHERN
INDIANA THURSDAY AFTERNOON.  THE MAIN ISSUE WITH THIS FORECAST IS THAT
MODELS INDICATE SOME CONVECTION OVER THE NEXT SEVERAL DAYS.  BUT IN MANY
CASES THEY SEEM TO BE OVER DOING THIS WITH THE BROAD UPPER RIDGE ACROSS
THE EASTERN U.S.

TEMPERATURES WILL REMAIN ABOVE NORMAL THROUGH THE SHORT TERM WITH HIGHS
IN THE MIDDLE TO UPPER 80S OVER MOST SECTIONS AND AROUND 90 IN THE SOUTHWEST.
LOWS WILL BE IN THE UPPER 60S TO AROUND 70.  IN MOST CASES WENT CLOSE
TO A MOS BLEND ON TEMPERATURES.

&&

.LONG TERM /FRIDAY THROUGH NEXT MONDAY/...
ISSUED AT 400 AM EDT TUE SEP 1 2015

ENSEMBLES IN GOOD AGREEMENT IN KEEPING A LARGE UPPER RIDGE ACROSS THE
EASTERN PARTS OF THE COUNTRY THROUGH THE END OF THE WEEK. HOWEVER...THE
ENSEMBLES ALSO SUGGEST A WEAKNESS IN THE UPPER RIDGE MAY EXTEND FROM THE
OHIO VALLEY INTO THE SOUTHEAST PARTS OF THE COUNTRY DURING THAT TIME.
THIS MAY RESULT IN SOME POTENTIAL FOR MAINLY AFTERNOON AND EARLY EVENING
CONVECTION FROM FRIDAY THROUGH SUNDAY. OTHER THAT THE WEAKNESS ALOFT...THERE
IS NOT A STRONG SIGNAL FOR PRECIPITATION WITH HIGH PRESSURE GENERALLY IN
CONTROL. FOR THESE REASONS...WILL KEEP THE FRIDAY THROUGH SUNDAY PERIOD DRY.

BY EARLY NEXT WEEK...THE ENSEMBLES SUGGEST A DECENT SHORT WAVE TROUGH MAY
MOVE ACROSS THE NORTHERN PLAINS AND GREAT LAKES...WHICH MAY EVENTUALLY FLATTEN
THE RIDGE. AN ASSOCIATED FRONTAL SYSTEM MAY APPROACH THE LOCAL AREA BY THAT TIME.
WILL GO WITH CHANCE POPS FOR NEXT MONDAY.

TEMPERATURES SHOULD BE ABOVE NORMAL GIVEN THE PRESENCE OF THE UPPER RIDGE.

&&

.AVIATION /DISCUSSION FOR 011800Z TAF ISSUANCE/...

ISSUED AT 106 PM EDT TUE SEP 1 2015

WIDELY SCATTERED THUNDERSTORMS ARE STARTING TO DWINDLE TO THE WEST
OF THE SITES AND STARTING TO PICK UP TO THE EAST. DON/T EXPECT ANY
OF THESE TO HAPPEN DIRECTLY OVER A SITE AT THIS POINT SO WILL LEAVE
OUT OF THE TAFS. AT KIND THOUGH WILL INCLUDE A VCTS WITH THUNDER
OCCURRING JUST TO THE NORTH AND WILL CARRY THIS FOR AN HOUR OR
TWO. VFR CU EXPECTED AT THE SITES THROUGH THE REST OF THE
AFTERNOON. DURING THE OVERNIGHT THE UPPER WAVE FORCING THE
CONVECTION WILL MOVE OUT AND ALLOW FOR MORE HIGH PRESSURE TO BUILD
IN WITH NEAR CALM WINDS AND PATCHY FOG. FOR NOW WILL GO WITH MVFR
FOG BASED ON LACK OF GROUND MOISTURE AT THE TAF SITES AND SOME
MIXING LEFT AS THE WAVE MOVES OUT.

&&

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

$$

SYNOPSIS...SMF/JH
NEAR TERM...SMF/JH
SHORT TERM...JH
LONG TERM...JAS
AVIATION...CP


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