Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 040227
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
1028 PM EDT SUN MAY 3 2015

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

&&

.SYNOPSIS...
ISSUED AT 226 PM EDT SUN MAY 3 2015

A FRONTAL SYSTEM IS EXPECTED TO STALL OVER OR NEAR THE NORTHERN
ZONES EARLY THIS WEEK...BEFORE DISSIPATING BY THE MIDDLE OF THE
WEEK. ANOTHER FRONTAL SYSTEM MAY AFFECT THE AREA BY NEXT WEEKEND.

&&

.NEAR TERM /REST OF TONIGHT/...
ISSUED AT 949 PM EDT SUN MAY 3 2015

SHOWERS AND THUNDERSTORMS ASSOCIATED WITH AN UPPER LEVEL WAVE ACROSS
NORTHERN ILLINOIS CONTINUE TO WEAKEN AS THEY MOVE INTO AN
UNFAVORABLE AIRMASS. CANNOT RULE OUT A SPRINKLE ACROSS THE EXTREME
NORTHWEST FORECAST AREA LATE THIS EVENING...BUT ODDS OF MEASURABLE
PRECIPITATION ARE TOO LOW TO MENTION.

FOCUS THEN TURNS TO OVERNIGHT AS CONVECTION CURRENTLY ACROSS THE
UPPER MIDWEST SLIDES SOUTHEAST TOWARD THE AREA. PREVIOUS FORECAST
HAS TRENDS WELL IN HAND SO ONLY MADE MINOR TWEAKS TO POPS.
CONVECTION WILL WEAKEN AS IT MOVES INTO THE AREA SO ONLY NORTHWEST
AREAS SHOULD SEE CHANCES BEFORE 12Z.

PREVIOUS DISCUSSION FOLLOWS...
MODEL DATA SUGGEST COLD FRONT CURRENTLY DROPPING SOUTHEAST THROUGH
THE NORTHERN MIDWEST WILL SAG INTO FAR NORTHERN ILLINOIS BY DAYBREAK
ON MONDAY. APPEARS THE MAIN THREAT OF CONVECTION WITH THIS FRONT
WILL REMAIN NORTHWEST OF THE LOCAL AREA TONIGHT...ALTHOUGH SOMETHING
COULD SNEAK INTO THE NORTHWEST ZONES TOWARDS DAYBREAK AS THE 850MB
JET SAGS INTO THAT AREA. WILL PUT SOME SMALL CHANCE POPS OVER THESE
AREAS TOWARDS SUNRISE.

BASED ON LOW LEVEL THICKNESSES...THE GFS MOS LOWS FOR TONIGHT LOOK
OK FOR THE MOST PART...SO ONLY MINOR ADJUSTMENTS PLANNED.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
ISSUED AT 226 PM EDT SUN MAY 3 2015

FRONTAL ZONE IS EXPECTED TO GET HUNG UP EITHER OVER THE NORTHERN
ZONES OR FARTHER NORTH ACROSS NORTHERN INDIANA ON MONDAY...BEFORE
EVENTUALLY DISSIPATING BY WEDNESDAY AS UPPER RIDGE BUILDS OVERHEAD.

OPERATIONAL MODELS ARE PROBABLY OVERESTIMATING THE AMOUNT OF
INSTABILITY SOUTH OF THE FRONT MONDAY AND TUESDAY DUE TO ERRONEOUSLY
HIGH DEWPOINTS TYPICAL OF THIS TIME OF YEAR...BUT THINK THERE WILL
BE SOME POTENTIAL FOR CONVECTION WITH THE FRONT NEARBY.
OVERALL...THE ENSEMBLES ARE WETTER THAN THE OPERATIONAL MODELS.
WILL GO WITH CHANCE POPS FOR MONDAY THROUGH TUESDAY...WITH THE
HIGHEST POPS IN THE NORTH.

MODELS ALSO SUGGEST SOME THREAT FOR DIURNAL CONVECTION ON WEDNESDAY.
CONSIDERING THE BUILDING UPPER RIDGE AND THE DISSIPATION OF THE
SURFACE FRONT...WILL CONTINUE TO KEEP THAT PERIOD DRY FOR NOW.

BASED ON PROGGED LOW LEVEL THICKNESSES...THE GFS MOS TEMPERATURE
GUIDANCE LOOKS REASONABLE FOR THE MOST PART. THE EXCEPTION IS THE
HIGHS ON TUESDAY...WHICH LOOK A LITTLE COOL. WILL RAISE THE NUMBERS
A CATEGORY AT THAT TIME

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
ISSUED AT 248 PM EDT SUN MAY 3 2015

THE RETURN OF RIDGING ALOFT CENTERED OVER THE EASTERN OHIO AND
TENNESSEE VALLEYS WILL BRING THE MOST PROLONGED STRETCH OF VERY
WARM WEATHER FOR THE REGION SO FAR THIS YEAR. IT FRANKLY WILL FEEL
LIKE SUMMER FOR MUCH OF THE EXTENDED.

KEY FEATURE THROUGHOUT THE PERIOD MAY END UP BEING A POSSIBLE
DEVELOPING LOW PRESSURE OFF THE SOUTH CAROLINA COAST. BULK OF THE
EXTENDED MODELS ARE PICKING UP ON THIS SYSTEM ORGANIZING NORTH OF
THE BAHAMAS LATE WEEK AND DRIFTING SLOWLY NORTH JUST OFF THE
COAST. WHILE THIS SYSTEM WILL NOT IMPACT OUR WEATHER DIRECTLY...
ITS LOCATION IN THE WESTERN ATLANTIC WOULD SERVE TO HOLD THE UPPER
RIDGE IN PLACE OVER THE OHIO VALLEY LONGER THAN PREVIOUSLY
THOUGHT AND SUBSEQUENTLY FORCE THE UPPER ENERGY OVER THE FOUR
CORNERS REGION TO TRACK INTO THE NORTHERN PLAINS. GLOBAL MODELS
ARE STARTING TO CAPTURE THIS TREND AND EVEN THE OP GFS IS SLOWER
WITH THE DEPARTURE OF THE RIDGE THAN A FEW DAYS AGO.

THIS WOULD RESULT IN A WARMER DRIER SCENARIO FOR LATE WEEK WITH
MORE WIDESPREAD CONVECTIVE POTENTIAL BACKING OFF UNTIL NEXT
WEEKEND IF NOT LONGER. WHILE ISOLATED DIURNAL CONVECTION IS
POSSIBLE BOTH THURSDAY AND FRIDAY IN THE WARM AIRMASS...CHANCES
ARE LOW ENOUGH TO KEEP CONDITIONS LARGELY DRY. BRING CHANCE POPS
INTO CENTRAL INDIANA FOR SATURDAY AND SUNDAY AS THE RIDGE SLOWLY
FLATTENS AND ENABLES A FRONTAL BOUNDARY TO MOVE INTO THE LOWER
GREAT LAKES.

WITH THE UPPER RIDGE REMAINING THE DOMINANT INFLUENCE FOR MUCH OF
THE EXTENDED...SEE NO REASON TO DEVIATE FROM SUPERBLEND GUIDANCE
WITH HIGHS IN THE 80S POSSIBLE EVERY DAY. CLIMATOLOGICALLY...COULD
SEE THE MOST 80+ DEGREE DAYS IN INDY OVER THE FIRST 10 DAYS OF MAY
SINCE 2001 SHOULD THIS ALL PAN OUT.

&&

.AVIATION /DISCUSSION FOR 040300Z KIND TAF UPDATE/...
ISSUED AT 1028 PM EDT SUN MAY 3 2015

MINOR TWEAKS MADE TO KIND TAF TO BETTER MATCH CURRENT CONDITIONS.
NO OTHER CHANGES ARE NEEDED AT THIS TIME.

PREVIOUS AVIATION DISCUSSION FOLLOWS...
MOSTLY VFR...BUT SCATTERED SHOWERS AND A FEW THUNDERSTORMS POSSIBLE
OVER THE NORTHERN HALF OF THE REGION AFTER DAYBREAK MONDAY.

A COLD FRONT OVER WESTERN IOWA AND WESTERN WISCONSIN WILL MOVE TO
NORTHWEST INDIANA BY END OF THE FORECAST PERIOD AND THEN BECOME
STATIONARY ACROSS NORTHERN INDIANA MONDAY NIGHT.

EXPECT MAINLY SCATTERED MID/HIGH CLOUDS EARLY ON. HIGH RESOLUTION
MODELS INDICATE SHOWERS AND A FEW THUNDERSTORMS MAY REACH KLAF AFTER
10Z AND WILL BEGIN MENTION OF VCSH AND THEN VCTS LATER  AT KLAF.
THESE SHOWERS AND THUNDERSTORMS COULD EVENTUALLY REACH AS FAR AS
KIND AND KHUF. BUT MODELS ARE IFFY WHETHER THEY WILL GET THAT FAR.
THUS FOR NOW WILL MENTION A PROB THUNDER MAINLY MONDAY AFTERNOON AT
KIND AND KHUF.  CHANCES FOR ANYTHING REACHING KBMG ARE TOO LOW TO
MENTION AT THIS TIME.

WINDS WILL BE FROM THE SOUTH 6 TO 10 KNOTS OVERNIGHT AND SOUTHWEST
UP TO 40 KNOTS AND FEW GUSTS TO 20 KNOTS ON MONDAY.

&&

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

&&

$$

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

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