Area Forecast Discussion
Issued by NWS Indianapolis, IN

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS63 KIND 262033
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
432 PM EDT SAT JUL 26 2014

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

&&

.SYNOPSIS...
ISSUED AT 404 PM EDT SAT JUL 26 2014

SEVERE WEATHER IS EXPECTED TONIGHT AND EARLY SUNDAY AS A COLD FRONT
DROPS THROUGH THE OHIO VALLEY. SCATTERED STORMS WILL REMAIN A
POSSIBILITY SUNDAY AS LOW PRESSURE TRACKS THROUGH THE LOWER GREAT
LAKES. MUCH COOLER AIR WILL EXPAND INTO THE REGION FOR MUCH OF
NEXT WEEK AS A LARGE UPPER TROUGH DEVELOPS OVER THE EASTERN PART OF
THE COUNTRY. CHANCES FOR THUNDERSTORMS WILL RETURN FOR THE SECOND
HALF OF THE WEEK.

&&

.NEAR TERM /REST OF THE AFTERNOON AND TONIGHT/...
ISSUED AT 404 PM EDT SAT JUL 26 2014

STRATOCU DECK HAS ADVANCED FURTHER INTO THE FORECAST AREA FROM THE
NORTH THAN PREVIOUSLY THOUGHT THIS AFTERNOON. THE CLOUDS WERE
HELPING TO LIMIT TEMP RISES A BIT...BUT STRONG MOISTURE ADVECTION
PERSISTING WITH INCREASINGLY HUMID AIRMASS OVER THE REGION. TEMPS
WERE GENERALLY LOW TO MID 80S AT 19Z.

FOCUS REMAINS ON POTENTIAL FOR SEVERE WEATHER TONIGHT WITH GREATEST
CONCERN ON WIDESPREAD DAMAGING WINDS AND FLOODING RAINFALL. FEW MORE
VARIABLES THIS AFTERNOON MAKING FOR A FRUSTRATING LOWER CONFIDENCE
THAN DESIRED WITH REGARDS TO CONVECTIVE INITIATION AT THIS LATE
STAGE. SHORT RANGE MODEL GUIDANCE EXHIBITING STRUGGLES RELATED TO
THESE VARIABLES. REGARDLESS OF THE PARTICULARS...SEVERE WEATHER/
FLOOD THREAT REMAINS HIGH OVER CENTRAL INDIANA THIS EVENING INTO THE
OVERNIGHT.

AFOREMENTIONED CLOUD DECK IN GREATER ABUNDANCE THAN ORIGINALLY
ANTICIPATED. WHILE THIS IS CUTTING DOWN ON EXPECTED HIGHS BY A FEW
DEGREES...IT APPEARS TO BE HAVING LITTLE IMPACT ON THE
DESTABILIZATION DUE TO THE STRONG MOISTURE ADVECTION EXPERIENCED FOR
MUCH OF THE DAY. DEWPOINTS HAVE HAD NO DIFFICULTY IN RISING INTO THE
LOWER 70S OVER MUCH OF THE FORECAST AREA...AND GLANCES TO THE
SOUTHWEST SHOW THE MID 70S DEWPOINTS ARE NOT FAR AWAY. LAPS
SOUNDINGS AND 700MB ANALYSIS INDICATED WARMER AIR ALOFT CONTRIBUTING
TO CAP DEVELOPMENT. MESOANALYSIS SHOWING PLENTY OF INSTABILITY
PRESENT ABOVE THE CAP...WITH 3000J/KG+ MLCAPE PRESENT JUST TO OUR
WEST. THE CAP WAS KEEPING A RELATIVE LID ON CONVECTION IN THE
IMMEDIATE VICINITY...AND SUSPECT IT IS CONTRIBUTING TO THE
DIFFICULTIES IN UPWARD CONVECTIVE DEVELOPMENT WITH STORMS OVER
MISSOURI. AS LONG AS THE CAP HOLDS...WHICH STILL IS LIKELY TO BE
UNTIL 23-00Z...HARD TO JUSTIFY MUCH MORE THAN ISOLATED STORMS ACROSS
THE REGION OVER THE NEXT FEW HOURS.

THE ARRIVAL OF A STRONGER LOW LEVEL JET TO NEAR 35KTS THIS
EVENING...COMBINED WITH INCREASED BL SHEAR VALUES AS MCV OVER
MISSOURI APPROACHES AND COOLING MAINTAINING ITS DISAPPEARANCE BY MID
EVENING. THETA-E RIDGE REMAINS POINTED TOWARDS THE REGION AND SHOULD
BE A FOCUS FOR STORM DEVELOPMENT. ADDITIONALLY...REMNANT OUTFLOW
BOUNDARIES FROM EARLIER TODAY AND DIFFERENTIAL HEATING BETWEEN HOT
TEMPS IN THE LOWER OHIO VALLEY AND 80S HERE MAY CONTRIBUTE TO NEW
STORM GROWTH. AVAILABLE INSTABILITY AND MOISTURE WILL PROMOTE RAPID
UPWARD CONVECTIVE EXPANSION THROUGH THE EVENING WITH THE POTENTIAL
FOR SEVERE WEATHER FOCUSED FROM 00Z INTO THE EARLY PART OF THE
OVERNIGHT. WIDESPREAD DAMAGING WINDS REMAIN THE PRIMARY SEVERE
THREAT...WITH MODEL SOUNDINGS INDICATING BROAD DRY ADIABATIC FLOW BY
03Z. PWATS IN EXCESS OF 2 INCHES THIS EVENING...COMBINED WITH THE
FREEZING LEVEL NEAR 15KFT AND A WEST-EAST ORIENTED LOW LEVEL JET
SUPPORTS POTENTIAL FOR FLOODING FROM TORRENTIAL RAINFALL. AT THIS
POINT...LIKELY BEST FOCUS FOR HEAVIEST RAINFALL WILL BE ALONG AND
SOUTH OF I-70. WILL INTRODUCE A FLASH FLOOD WATCH FOR TONIGHT
FOCUSED FROM THE I-70 CORRIDOR SOUTH AS A RESULT.

STORMS WILL CONTINUE OVERNIGHT...BUT GRADUAL FOCUS TO HEAVIEST
STORMS WILL TRANSITION OFF TO THE SOUTH AND EAST AFTER 06-07Z WITH
COVERAGE DIMINISHING TOWARDS DAYBREAK.

TEMPS...LEANED TOWARDS WARMER MET GUIDANCE AS TEMPS SHOULD NOT GO
ANY LOWER THAN 70-75.

&&

.SHORT TERM /SUNDAY THROUGH TUESDAY/...
ISSUED AT 404 PM EDT SAT JUL 26 2014

FORECAST CHALLENGES FOCUS ON PRECIP AND SEVERE WEATHER CHANCES
SUNDAY...FOLLOWED BY TEMPS MONDAY/TUESDAY AS AN UPPER TROUGH
DEVELOPS OVER THE REGION.

CONVECTIVE EVOLUTION REMAINS UNCERTAIN FOR SUNDAY AND LARGELY
DEPENDENT ON HOW MUCH DESTABILIZATION CAN TAKE PLACE BEHIND
OVERNIGHT ACTIVITY. DEEPER MOISTURE WILL SHIFT EAST OF THE REGION AS
LOW PRESSURE DEVELOPS OVER SOUTHERN LOWER MICHIGAN. WHILE DRIER AIR
IS PRESENT AND BETTER FORCING LIKELY TO BE OFF TO THE EAST IN
OHIO...PRESENCE OF MODEST INSTABILITY AND STEEPENING LAPSE RATES IN
THE AFTERNOON REMAINS SUPPORTIVE OF SCATTERED CONVECTION...
ESPECIALLY ACROSS THE EASTERN HALF OF THE FORECAST AREA. SEVERE
POTENTIAL REMAINS UNCERTAIN AND LIKELY WILL DEPEND ON HOW UNSTABLE
ATMOSPHERE CAN GET IN THE AFTERNOON.

REMAINDER OF THE SHORT TERM WILL SEE A GRADUAL TRANSITION TO A DEEP
UPPER TROUGH SETTLING OVER MUCH OF THE EASTERN U S. THIS WILL
TRANSITION TO A MUCH COOLER PATTERN FOR CENTRAL INDIANA. PASSAGE OF
THE UPPER WAVE TO THE NORTHEAST OF THE AREA MONDAY WILL BRING A FEW
SHOWERS INTO THE EASTERN HALF OF THE FORECAST AREA. BEYOND
THAT...DRIER AIR WILL FILTER INTO THE OHIO VALLEY.

TEMPS...GENERALLY TRENDED TOWARDS MAVMOS GUIDANCE THROUGHOUT THE
PERIOD. WILL REMAIN WARM AND HUMID SUNDAY BEFORE TEMPS FALL EARLY IN
THE WEEK. HIGHS BY TUESDAY LIKELY TO BE A GOOD 10-15 DEGREES BELOW
NORMAL. TOOK A MOS BLEND ON LOWS. MAY SEE SOME UPPER 40S IN OUTLYING
AREAS MONDAY NIGHT.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...

ISSUED AT 230 PM EDT SAT JUL 26 2014

MAIN FORECAST CHALLENGE WILL BE PERIODIC CHANCES FOR PRECIPITATION.

THE PERIOD BEGINS WITH THE CONTINUATION OF STRONG UPPER LEVEL
RIDGING ACROSS THE WESTERN CONUS AND DECENT TROUGHING ACROSS THE
EAST. A STRONG UPPER LOW OVER HUDSON BAY WILL PUT CENTRAL INDIANA
BACK INTO A NORTHWEST FLOW PATTERN WITH THE POSSIBILITY OF SEVERAL
SHORTWAVES TO PASS THROUGH THE AREA. THEREFORE...DIURNAL CHANCES FOR
THUNDERSTORMS THROUGH THE END OF THE WORK WEEK...AS INDICATED BY THE
REGIONAL INITIALIZATION...CONTINUES TO APPEAR THE BEST WAY TO HANDLE
THINGS.

BOTH THE GFS AND ECMWF CLOSE OFF AN UPPER LOW ACROSS THE OHIO VALLEY
LATE IN THE PERIOD. THE BEST CHANCE FOR PRECIPITATION WILL DEPEND ON
THE EXACT PLACEMENT OF THIS SYSTEM AND ITS ASSOCIATED VORTICITY
MAXIMUMS.

TEMPERATURES WILL CONTINUE TO BE WELL BELOW NORMAL UNDER NORTHWEST
FLOW WITH READINGS TOPPING OUT IN ONLY THE UPPER 70S/LOW 80S THROUGH
THE PERIOD.

&&

.AVIATION /DISCUSSION FOR 26/2100Z KIND TAF UPDATE/...
ISSUED AT 432 PM EDT SAT JUL 26 2014

MINOR TWEAKS MADE TO KIND TAF TO BETTER MATCH CURRENT CONDITIONS. NO
OTHER CHANGES NEEDED AT THIS POINT. PORTION OF PREVIOUS AVIATION
DISCUSSION FOLLOWS...

MVFR CEILINGS OR LOW VFR CEILINGS WILL BE THE RULE WITH LOWER
CONDITIONS POSSIBLE WITH THUNDERSTORMS THIS EVENING AND TONIGHT.

THERE IS STILL PLENTY OF UNCERTAINTY IN REGARDS TO THE TIMING OF
STORMS ENTERING CENTRAL INDIANA. CURRENT THINKING IS THAT
STORMS...AND ASSOCIATED MVFR OR EVEN BRIEF IFR CONDITIONS IN HEAVY
RAIN...WILL IMPACT KLAF BETWEEN 23-01Z AND SPREAD EASTWARD TO THE
REMAINDER OF THE TERMINALS IMPACTING KIND AROUND 01-03Z. TIMING WILL
MORE THAN LIKELY NEED TO BE REFINED AS CONVECTION DEVELOPS TO THE
WEST LATER THIS AFTERNOON. OUTSIDE OF ANY STORMS...WINDS WILL
GENERALLY BE OUT OF THE SOUTHWEST AT 5-10 KTS.

TIMED THE EXIT OF STORMS AND RETURN FOR THE 07-09Z TIME FRAME WITH
LINGERING MVFR CEILINGS. WINDS WILL BEGIN TO TURN JUST A TAD MORE
WESTERLY REMAINING AROUND 5-10 KTS.

HAVE INTRODUCED VCTS FOR SUNDAY AFTERNOON IN THE 30 HOUR TAF FOR
KIND AS ANOTHER ROUND OF STORMS IS POSSIBLE TO END THE WEEKEND.
HOWEVER...THE LIKELIHOOD OF THESE STORMS IS LIKELY CONTINGENT ON THE
CONVECTIVE SCENARIO THAT PLAYS OUT TONIGHT AND EARLY SUNDAY.

&&

.IND WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH FROM 8 PM EDT THIS EVENING THROUGH SUNDAY
MORNING FOR INZ043>049-051>057-060>065-067>072.

&&

$$

SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....LEE
AVIATION...LEE/JH

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









USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.