Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 221450
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
1050 AM EDT FRI AUG 22 2014

.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.

&&

.SYNOPSIS...
ISSUED AT 235 AM EDT FRI AUG 22 2014

AN ACTIVE AND WARM WEATHER PATTERN WILL REMAIN IN PLACE THROUGH
THE WEEKEND AS A RIDGE OF HIGH PRESSURE BUILDING ACROSS THE
MISSISSIPPI RIVER VALLEY. THIS WILL ALLOW VERY WARM AND HUMID AIR
TO PUSH INTO THE OHIO VALLEY. MEANWHILE...SEVERAL UPPER LEVEL
WEATHER DISTURBANCES ARE EXPECTED TO PUSH INTO NORTHERN AND
CENTRAL INDIANA ALONG A LINGERING FRONTAL BOUNDARY. THIS WILL
RESULT IN DAILY CHANCES FOR SHOWERS OR STORMS THROUGH THE WEEKEND.

NEXT WEEK ANOTHER FRONTAL SYSTEM WILL BRING ADDITIONAL CHANCES
FOR RAIN AND WILL EVENTUALLY BRING A RETURN TO NEAR AVERAGE
TEMPERATURES.

&&

.NEAR TERM /REST OF TODAY/...
ISSUED AT 1050 AM EDT FRI AUG 22 2014

CONVECTION CONTINUES TO WEAKEN AND DECREASE IN COVERAGE OVER THE
NORTHERN HALF OF THE FORECAST AREA AS OF 1430Z. CLOUDS AND RAIN
WERE KEEPING TEMPS IN THE 70S ACROSS MUCH OF THE AREA WITH SOME
LOWER 80S OVER FAR SOUTHERN PORTIONS OF THE REGION.

VERY HIGH UNCERTAINTY IN THE FORECAST FOR THE REST OF THE DAY.
MODEL GUIDANCE REMAINS POOR AT BEST IN DEPICTING THE MESOSCALE
DETAILS THAT CONTINUE TO DRIVE THE FORECAST. WHILE WEAKENING TO
CURRENT CONVECTION OVER THE REGION SHOULD CONTINUE INTO EARLY
AFTERNOON WITH THE LOSS OF THE NOCTURNAL JET...REDEVELOPMENT TO
STORMS OVER WESTERN ILLINOIS POSING MORE QUESTIONS WITH RESPECT TO
DOWNSTREAM IMPACTS LATER THIS AFTERNOON. THESE STORMS BEING AIDED
BY YET ANOTHER WAVE ALOFT OVERTOPPING THE RIDGE. EXPECT CONVECTION
TO RIDE THE THETA E RIDGE AND EXTRAPOLATION WOULD TRACK THESE
STORMS INTO THE FORECAST AREA AFTER 18Z.

SHORT RANGE GUIDANCE DOES DESTABILIZE THE AIRMASS ONCE AGAIN BY
THIS AFTERNOON...BUT THAT IS ASSUMING SOME REMOVAL OF THE CLOUD
DEBRIS. WHILE CLOUDS ARE LIKELY TO HOLD ACROSS MUCH OF OUR
FORECAST AREA INTO THE AFTERNOON...EVEN THINNING OF THE DECK
SHOULD ENABLE SOME HEATING AND DESTABILIZATION TO OCCUR LATE
TODAY. ANOTHER FACTOR IS A WELL DEVELOPED OUTFLOW BOUNDARY THAT
SURGED SOUTH FROM OVERNIGHT CONVECTION ALL THE WAY INTO SOUTHERN
INDIANA. RECENT VIS SATELLITE ANALYSIS SHOWS THIS BOUNDARY NOW
SHIFTING BACK NORTH INTO THE AREA AND MAY SERVE AS AN ADDITIONAL
FOCUS FOR CONVECTION LATER TODAY. CONSIDERING ABOVE THOUGHTS...WILL
MAINTAIN CONVECTIVE CHANCES FOR THE ENTIRE FORECAST AREA FOR THE
REST OF THE DAY.

HAVE ALSO CHOSEN TO EXPAND THE FLASH FLOOD WATCH BACK WEST TO
TIPPECANOE/CARROLL COUNTIES TO ENCOMPASS THE HEAVIEST RAINFALL
AREAS OVER THE LAST 24-30 HOURS. RAINFALL TOTALS OF 3-4`+ ARE
COMMON ACROSS THE WATCH AREA WITH A BULLSEYE OF 6-8" HAVING FALLEN
SINCE THURSDAY MORNING OVER DELAWARE/RANDOLPH COS. ANY RAINFALL
WILL EXACERBATE ONGOING FLOODING. WILL REEVALUATE POTENTIAL TO
EXPAND WATCH IN TIME WITH AFTERNOON FORECAST PACKAGE.
FINALLY...BUMPED HIGHS DOWN A FEW DEGREES MOST AREAS WITH CLOUDS
LIMITING HEATING THIS MORNING. EVEN A SHORT WINDOW OF FILTERED SUN
HOWEVER SHOULD ENABLE TEMPS INTO THE 80S.

ZONE AND GRID UPDATE OUT.

&&

.SHORT TERM /TONIGHT THROUGH MONDAY/...

ISSUED AT 235 AM EDT FRI AUG 22 2014

GFS AND NAM SUGGEST LITTLE OVERALL CHANGE IN THE ONGOING PATTERN
TONIGHT AND SATURDAY. THE UPPER RIDGE TO THE WEST CONTINUES TO ALLOW
WEAK UPPER DISTURBANCES TO SPILL SOUTHEAST INTO INDIANA. THE
WARM...HUMID AND CONDITIONALLY UNSTABLE AIRMASS REMAINS IN PLACE.
FORECAST SOUNDINGS REMAIN DEEPLY SATURATED WITH VERY HIGH
PRECIPITABLE WATER VALUES. LINGERING SURFACE BOUNDARY REMAINS IN
PLACE ALSO. THUS WILL RAISE POPS TONIGHT AND ON SATURDAY AS THESE
FEATURES CONTINUE TO REMAIN IN PLACE. GIVEN THE EXPECTED CLOUDS AND
RAIN...WILL CONTINUE TO TREND OF LEANING WARMER THAN MAVMOS ON LOWS
AND COOLER ON HIGHS.

ON SATURDAY NIGHT THROUGH MONDAY...THE UPPER RIDGE AXIS BEGINS TO
DRIFT EAST...WHICH BEGINS TO ALLOW DRIER AIR TO ENTER THE FORECAST
COLUMN. THE UPPER STEERING FLOW BEGINS TO SHIFT ANY RIDGE RIDING
SHORT WAVES WELL EAST OF INDIANA. WITH ET DRIER AIR ARRIVING
PRECIPITABLE WATER IN THE FORECAST SOUNDINGS FALLS TO LESS THAN
1.75 IN. ALSO 700MB TEMPS RISE TOWARD 10C...OFTEN A KEY CAPPING
TEMPERATURE. THUS WILL TREND POPS AT OR BELOW MAVMOS ON SUNDAY
THROUGH MONDAY. AS FOR TEMPS...WILL TREND HIGHS AND LOWS WARMER
THAN MAVMOS GIVEN THE VERY WARM AIR MASS THAT IS EXPECTED ACROSS
THE AREA.

&&

.LONG TERM /MONDAY NIGHT THROUGH NEXT THURSDAY/...

ISSUED AT 235 AM EDT FRI AUG 22 2014

ENSEMBLES SUGGEST UPPER RIDGE INITIALLY OVER THE AREA AT THE
BEGINNING OF THE PERIOD WILL EVENTUALLY GET SUPPRESSED BACK TO THE
SOUTH AS AN UPPER TROUGH MOVES INTO THE NORTHERN MIDWEST OR GREAT
LAKES BY THE MIDDLE OF NEXT WEEK.

ENSEMBLES SUGGEST PRECIPITATION POTENTIAL WILL MOVE BACK INTO THE
AREA STARTING NEXT TUESDAY AS UPPER RIDGE BEGINS TO FLATTEN
OUT...WITH THE BEST CHANCES NEXT WEDNESDAY AND THURSDAY AS A FRONTAL
SYSTEM ASSOCIATED WITH THE APPROACHING UPPER TROUGH MOVES IN. WILL
KEEP CHANCE POPS GOING IN THE FORECAST FROM TUESDAY THROUGH NEXT
THURSDAY.

&&

.AVIATION /DISCUSSION FOR THE 221500Z TAF UPDATE/...
ISSUED AT 1028 AM EDT FRI AUG 22 2014

AREA OF THUNDERSTORMS HAS WEAKENED SO HAVE PULLED IMMEDIATE THUNDER
THREAT FROM THE TAFS. THERE ARE SOME AREAS OF PATCHY MVFR BOTH IN
AND OUT OF THE RAIN AREAS...SO HAVE PUT TEMPOS IN TO COVER THIS.
MUCH UNCERTAINTY EXISTS IN HOW CONVECTIVE SITUATION WILL EVOLVE
UPSTREAM...SO HAVE JUST PUT IN VCTS AT KIND AND KHUF FOR THE
AFTERNOON.

PREVIOUS DISCUSSION FOLLOWS...
THUNDERSTORM CLUSTERS CONTINUE TO DROP SOUTHEAST ACROSS NORTHERN
ILLINOIS AND NORTHERN INDIANA. INTENSITY HAS FOR THE MOST PART BEEN
FAIRLY STEADY...ALTHOUGH CLOUD TOPS HAVE SHOWN A TENDENCY TO COOL
OVER THE PAST HOUR. PROFILERS STILL SHOWING DECENT INFLOW OF 25-30
KTS INTO THE CLUSTERS...SO EXPECTING CONVECTION TO CONTINUE FOR
AWHILE LONGER BEFORE WEAKENING LATER THIS MORNING. APPEARS KLAF/KIND
AND PROBABLY KHUF HAVE A GOOD CHANCE OF A DIRECT IMPACT FROM
CONVECTION THROUGH ABOUT 221600Z...WITH LOWER CONFIDENCE AT KBMG.
PERIODS OF IFR VISIBILITY RESTRICTIONS EXPECTED IN THE HEAVIER CELLS.

SHOULD SEE A BREAK IN THE CONVECTIVE THREAT AROUND MIDDAY INTO THE
AFTERNOON HOURS...BUT MODELS SUGGEST A RENEWED THREAT AFTER ABOUT
222100Z-222200Z AND ON INTO THE EVENING HOURS WITH A POTENTIAL UPPER
WAVE MOVING OUT OF THE IOWA REGION.

OUTSIDE OF CONVECTION...CEILINGS GENERALLY ABOVE 050 TODAY WITH
SURFACE WINDS 210-240 AT 6-8 KTS. VARIABLE AND GUSTY WINDS ALONG
WITH LOWER CEILINGS IN AND NEAR CONVECTION.

&&

.IND WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 10 PM EDT THIS EVENING FOR INZ021-
029>031-038>042-049.

&&

$$

SYNOPSIS...PUMA
NEAR TERM...RYAN
SHORT TERM...PUMA
LONG TERM...JAS
AVIATION...JAS/50

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