Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
203 PM EDT TUE JUN 30 2015

.UPDATE...
THE SYNOPSIS...NEAR TERM AND SHORT TERM SECTIONS HAVE BEEN UPDATED BELOW.

&&

.SYNOPSIS...
ISSUED AT 204 PM EDT TUE JUN 30 2015

TWO WEATHER SYSTEMS WILL DOMINATE INDIANA WEATHER INTO THE WEEKEND. 
ONE IS AN OLD FRONT AND THE OTHER IS AN AREA OF HIGH PRESSURE.

AT TIMES THE FRONT IS GOING TO BE OVER INDIANA. AT OTHER TIMES IT 
WILL BE TO OUR SOUTH.  IT LOCATION IS GOING TO BE DETERMINED BY THE 
HIGH PRESSURE AREA.  THE AREA SHOULD REMAIN CENTERED TO OUR 
NORTH...BUT WILL CHANGE SIZE SEVERAL TIMES. WHEN IT IS LARGE...THE 
FRONT WILL BE PUSHED SOUTH. WHEN IT SHRINKS...THE FRONT WILL RETURN 
TO OUR STATE.

NEXT WEEK THERE SHOULD BE A CHANGE. HIGH PRESSURE IS FORECAST TO 
STRENGTHEN TO THE SOUTHEAST OF THE HOOSIER STATE AS ANOTHER FRONT 
APPROACHES FROM THE WEST. 


&&

.NEAR TERM /TONIGHT/...

ISSUED AT 204 PM EDT TUE JUN 30 2015

THE MAIN PROBLEM IS HOW MUCH PRECIPITATION THERE WILL BE. 

THE HRR SHOWS A LOT DEVELOPING THIS AFTERNOON. THIS SEEMS LOGICAL 
SINCE WE ARE CLOSE TO THE CONVECTIVE TEMPERATURE AND THERE IS CLOUD 
OVER CENTRAL ILLINOIS SUGGESTING A SHORT WAVE IS APPROACHING.

THE HRR ALSO SHOWS PRECIPITATION DYING VERY RAPIDLY AROUND 00Z. 
AGAIN...THIS IS LOGICAL. THE SHORT WAVE SHOULD BE PULLING AWAY JUST 
AS DAYTIME HEATING IS LOST.

ALL THIS MEANS AN EVENING PERIOD WITH SCATTERED STORMS IS IN ORDER. 
THE OVERNIGHT ITSELF WILL NEED ONLY A LESSER CHANCES EARLY ON FOR 
ANY RESIDUAL STUFF. GIVEN ALL THAT CONSIDERABLE CLOUDINESS EARLY 
SHOULD GIVE WAY TO CLEARING LATER.

TEMPERATURES ARE LIKELY TO BE SLIGHTLY COOLER THAN LAST NIGHT. 
ALTHOUGH THE BASIC PATTERN HAS NOT CHANGED MUCH SKIES WILL BE 
CLEARER. THIS PUTS LOWS IN LINE WITH MAV.


&&

.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...

ISSUED AT 204 PM EDT TUE JUN 30 2015


THE MAIN QUESTION REMAINS WHAT POPS WILL BE.

ALL MODELS AGREE THE OVERALL PATTERN IS NOT CHANGING MUCH. HOWEVER 
THE DEVIL IS IN THE DETAILS IN THESE SITUATIONS WHERE CONVECTION IS 
THE MAIN THING. 

THERE IS NO SOLUTION WE CAN HAVE GREAT CONFIDENCE IN...BUT THE GFS 
IS THE THING TO BASE THE FORECAST ON. ITS A STRONG MODEL AND IS 
PRETTY CONSISTENT WITH THE ENSEMBLE NAM. THIS GIVES CONFIDENCE  
IT WILL BE RIGHT. THE OPERATIONAL NAM IS AN OUTLIER. GIVEN IT OFTEN 
STRUGGLES WITH CONVECTION/LATENT ISSUES IT WONT GET MUCH WEIGHT.

ALL TOLD...THE MAV WILL BE USED WITH LITTLE ALTERATION. SIGNIFICANT 
CHANGES MAY BE NEEDED LATER AS WE GET A BETTER HANDLE ON DETAILS.

FOR QPF...THE HPC GUIDANCE LOOKS OK UNTIL FRIDAY NIGHT CONSIDERING 
WHERE THE RAIN SHOULD BE. AFTER THAT THE SUPERBLEND QPF WILL BE 
USED. HPC GUIDANCE SEEMS OUT OF LINE WITH WHERE THE POPS SHOULD BE 
HIGH.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...

ISSUED AT 147 PM EDT TUE JUN 30 2015

MODELS BEGIN TO SUGGEST A MODERATION OF THE HIGHLY AMPLIFIED UPPER
FLOW TRANSITIONING TOWARD MORE OF A ZONAL FLOW ON TUESDAY. FRIDAY
AND SATURDAY CONTINUE TO SHOW THE TROUGHY PATTERN IN PLACE ALOFT
ACROSS THE OHIO VALLEY. THIS ALONG WITH EXPECTED EMBEDDED
SHORTWAVES WITHIN THE FLOW SUGGEST CHANCES FOR SHOWERS AND STORMS
EACH DAY.

BY SATURDAY NIGHT AND SUNDAY THE UPPER PATTER BEGINS TO
FLATTEN...BECOMING MORE ZONAL. HOWEVER THE GFS SHOWS A
LINGERING...POORLY ORGANIZED UPPER LOW OVER THE OHIO VALLEY
THROUGH THE PERIOD. WITH A WARM AND MOIST AIR MASS STILL IN
PLACE...DAILY CHANCES FOR SHOWERS STILL CANNOT BE RULED OUT WITH
THIS FEATURE PRESENT.
 
AGAIN...WITH A LACK OF SOUTHERLY FLOW INTO THE OHIO VALLEY...WILL
TREND TEMPS BELOW SEASONAL NORMALS.

&&

.AVIATION /DISCUSSION FOR THE 301800Z TAFS/...

ISSUED AT 1249 PM EDT TUE JUN 30 2015

MAINLY VFR CONDITIONS ARE EXPECTED THIS TAF PERIOD.

TAIL FROM MCV CURRENTLY EXITING THE FORECAST AREA. FORECAST
SOUNDINGS CONTINUE TO SUGGEST ATTAINABLE CONVECTIVE TEMPS THIS
AFTERNOON WITH DECENT CAPE AVAILABLE...HOWEVER CONFIDENCE IS LOW
FOR DEVELOPMENT AS SUBSIDENCE WITHING THE WAKE OF THE DEPARTING
MCV APPEARS TO BE AN UNFAVORABLE AREA FOR DEVELOPMENT. THUS WILL
JUST TREND TOWARD VCTS WITH BKN CLOUDS AT THE CCL LEVELS NEAR 4K
FT THIS AFTERNOON TO ACCOUNT FOR POP UP SHOWERS.

LIGHT WINDS AND PLENTY OF LOWER LEVEL MOISTURE MAY LEAD TO SOME
MVFR FOG CONDITIONS AT LAF...BMG AND HUF.

A RETURN TO VFR WILL BE EXPECTED AGAIN ON WEDNESDAY AFTER 14Z AS
DAYTIME HEATING BURNS OFF ANY FOG AND DIURNAL CU ONCE AGAIN BEGINS
TO DEVELOP.


&&

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

$$

SYNOPSIS...JK
NEAR TERM...JK
SHORT TERM...JK
LONG TERM....PUMA
AVIATION...JP

VISIT US AT HTTP://WWW.WEATHER.GOV/IND

FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSINDIANAPOLIS
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS

National Weather Service Glossary of Abbreviations