Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 300952
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
552 AM EDT SAT APR 30 2016

.SYNOPSIS...
ISSUED AT 354 AM EDT SAT APR 30 2016

RAIN WILL OVERSPREAD THE AREA FROM SOUTHWEST TO NORTHEAST
TODAY...BRINGING A HALF INCH OR MORE OF RAIN TO THE AREA. A
THUNDERSTORM IS POSSIBLE IN A FEW AREAS THIS AFTERNOON AND EARLY
EVENING SOUTH OF ROUTE 30. THE CLOUDS AND RAIN WILL KEEPS
TEMPERATURES ON THE COOL SIDE...REACHING IN TO THE 50S FOR HIGHS.
LOWS TONIGHT WILL RANGE FROM THE MIDDLE 40S NORTH TO AROUND 50
SOUTH.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 354 AM EDT SAT APR 30 2016

DRY CONDITIONS SHOULD PERSIST FOR MOST AREAS THROUGH 12Z THIS
MORNING AS SFC WARM FRONT AND INCREASED THETA E SURGE REMAINS
FROM EAST OF KANSAS CITY TO NORTH OF ST LOUIS INTO NW KENTUCKY.
WHILE NORTHWARD PROGRESS IS BEING MADE IT IS VERY SLOW AS
SUGGESTED TO BY MAJORITY OF MODELS. SOME LIGHTER PRECIP WAS NOTED
FROM SE IOWA INTO CENTRAL IL BUT LITTLE MORE THAN SPRINKLES NOTED.
SUSPECT THIS AREA WILL WEAKEN SOME AS IT PROGRESSES NORTH AND
ENCOUNTERS A SOMEWHAT DRIER NE FLOW BUT COULD BRING SOME SPRINKLES
OR BARELY MEASURABLE PRECIP INTO FAR SW AREAS PRIOR TO 12Z. BASED
ON THIS HAVE CONTINUED WITH A SOMEWHAT SLOWER TREND TO ARRIVAL OF
RAIN AS ISENTROPIC LIFT BEGINS AFTER 12Z SAT AND PEAKS 18Z TO 00Z
SUN WITH 40 TO 50 KT CROSS FLOW OVER 295 TO 300K PRESSURE SURFACES
YIELDING WHAT SHOULD TURN OUT TO BE A LARGE AREA OF STEADY RAIN.
CAN`T RULE OUT SOME THUNDER EMBEDDED WITHIN THE AREA...BUT
GREATEST CHANCE FOR CONVECTION WOULD OCCUR ON THE SOUTHERN FLANK
OF THE AREA CLOSER TO THE WARM FRONT AND LIMITED INSTABILITY. HAVE
LEFT SLGT CHC THUNDER MENTION LATE AM INTO EARLY EVE GENERALLY
SOUTH OF US 30 WITH NO SIG CHANGES FOR THE AREA ON THE NEW DAY 1
SPC OUTLOOK. MOST LOCATIONS SHOULD SEE ONE HALF TO THREE QUARTERS
OF AN INCH OF RAIN WITH POTENTIAL FOR SOME LOCATIONS TO SEE AN
INCH OR SO.

RAINFALL COULD BEGIN TO WIND DOWN TOWARDS 00Z SUN IN SW AREAS BUT
HAVE KEPT CAT POPS INTO EARLY EVE BEFORE TAPERING OFF TO CHC
SHOWERS/STORMS INTO THE OVERNIGHT HOURS. NO MAJOR CHANGES IN
TEMPERATURES AS WARM FRONT WILL GENERALLY REMAIN NEAR/SOUTH OF US-24
CORRIDOR BY 12Z SUN.

&&

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 354 AM EDT SAT APR 30 2016

A LULL IN GREATER RAIN COVERAGE SHOULD CONTINUE INTO EARLY SUNDAY AS
LEAD SHORT WAVE SHIFTS OFF TO THE NORTHEAST AND LOW LEVEL FLOW
BECOMES MORE VEERED. RAIN SHOWER COVERAGE SHOULD INCREASE ONCE AGAIN
BY SUNDAY AFTERNOON AS DAMPENING/SHEARING UPPER LEVEL PV ANOMALY
APPROACHES THE SOUTHERN GREAT LAKES/OHIO VALLEY. IT STILL APPEARS AS
THOUGH BEST CHANNELED DCVA SHOULD AFFECT ESPECIALLY SOUTHEAST HALF
OF FORECAST AREA SUNDAY AFTERNOON. OF LOW CONFIDENCE FOR SUNDAY IS
CONVECTIVE POTENTIAL AND EXTENT OF THUNDER. SUBTLE DIFFERENCES IN
LOW LEVEL FEATURES WILL HAVE A LARGE IMPACT ON THERMODYNAMIC
PROFILES SUNDAY WITH NAM/GFS EXHIBITING QUITE A LARGE DIFFERENCE IN
AFTERNOON INSTABILITY. 00Z NAM REMAINS A FAST/STRONG OUTLIER IN
TERMS OF SFC REFLECTION THROUGH THE AREA EARLY SUNDAY MORNING IN
COMPARISON TO BULK OF OTHER GUIDANCE. HAVE SOME CONCERN THAT NAM MAY
BE TOO INFLUENCED BY PRIOR 12-24 HOUR UPSTREAM CONVECTION AND
PERHAPS A LITTLE CONTAMINATED WITH SFC/LOW LEVEL EVOLUTION EARLY
SUNDAY. WITH PREFERENCE TO SLOWER EC/GFS...LOW LEVEL THERMAL
RIDGING/INSTABILITY AXIS WOULD EXHIBIT GREATER NORTHWARD ADVANCEMENT
ACROSS CENTRAL/NORTHERN PORTIONS OF THE FORECAST AREA SUNDAY
AFTERNOON. WHILE MID LEVEL LAPSE RATES SHOULD STEEPEN SUNDAY
AFTERNOON DUE TO DIFFERENTIAL ADVECTION...DEPTH OF MOISTURE AND
ABILITY TO REALIZE THESE STEEPER MID LEVEL LAPSE RATES REMAINS AN
ITEM OF LOWER CONFIDENCE. DID EXPAND ISOLD THUNDER MENTION ACROSS
FAR NORTHERN INDIANA. CANNOT COMPLETELY RULE OUT POTENTIAL OF FEW
STRONGER STORMS ACROSS SOUTHEAST HALF OF THE AREA SUNDAY AFTERNOON
GIVEN POTENTIAL WEAK-MODERATE INSTABILITY AND INCREASING SHEAR
PROFILES ASSOCIATED WITH UPPER SPEED MAX NOSING ACROSS THE OHIO
RIVER VALLEY PLACING THE AREA IN FAVORABLE LEFT EXIT REGION...BUT
AGAIN CONFIDENCE IS ON THE LOW SIDE DUE TO UNCERTAINTY IN REGARDS TO
WHERE SHARPER BAROCLINIC ZONE/LOW LEVEL MOISTURE GRADIENT SETS UP.

FOR SUNDAY NIGHT...POCKET OF STEEPER MID LEVEL LAPSE RATES SHOULD BE
EXITING THE EAST WITH UPPER PV ANOMALY SLOW TO DEPART. THIS SHOULD
ALLOW FOR SCATTERED SHOWERS TO PERSIST INTO SUNDAY EVENING BEFORE
DIMINISHING OVERNIGHT. CLOUDS WILL DECREASE ON EARLY MONDAY WITH
JUST SOME FAIR WEATHER CU DEVELOPING IN THE AFTERNOON. HIGHS ON
MONDAY SHOULD REACH INTO THE UPPER 50S/LOWER 60S...BUT AIR MASS WILL
BE CONSIDERABLY DRIER.

GENERAL THEME OF THE REMAINDER OF THE LONG TERM REMAINS UNCHANGED
WITH UPPER VORT EXPECTED TO DROP ACROSS GREAT LAKES REGION
WEDNESDAY/THURSDAY WITH NEXT FROPA FOR WEDNESDAY. LOW LEVEL W-NW
FLOW WILL LIMIT SIGNIFICANT MOISTURE RETURN AHEAD OF THIS FRONT BUT
WILL KEEP CHANCE POPS IN PLACE WITH BAND OF SHOWERS LIKELY TO
ACCOMPANY THIS FRONTAL BOUNDARY. UPON COLLABORATION WITH SURROUNDING
WFOS DID GO A LITTLE COOLER FOR THE THURSDAY-FRIDAY PERIOD AS
CONFIDENCE IN BROAD LOW LEVEL THERMAL TROUGHING IS BEGINNING TO
INCREASE FOR THIS PERIOD WHICH SHOULD KEEP TEMPS BELOW SEASONABLE
NORMS FOR END OF THE WEEK.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 546 AM EDT SAT APR 30 2016

LEADING EDGE OF AN AREA OF RAIN WAS WORKING NORTHEAST. INITIALLY
LITTLE OVERALL IMPACT AS CIGS WILL TAKE SOME TIME TO
LOWER...EVENTUALLY REACHING MVFR NEAR/AFTER 15Z AND THEN DROPPING
RAPIDLY INTO IFR BY AFTERNOON AS HEAVIER RAIN MOVES IN. THE
STEADY RAIN SHOULD DEPART AFTER 00Z...BUT LOW CLOUDS AND FOG WILL
LINGER THROUGH THE REMAINDER OF THE PERIOD WITH IFR/LIFR CIGS AND
VSBYS EXPECTED. AS WITH 6Z TAFS...NO MENTION OF THUNDER HAS BEEN
ADDED BUT TRENDS WILL NEED TO BE WATCHED ON BACK EDGE OF THE RAIN
AREA AS WELL AS DURING THE OVERNIGHT HOURS OF SUNDAY AS MODEST
INSTABILITY WILL START TO MOVE IN.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&

$$

SYNOPSIS...FISHER
SHORT TERM...FISHER
LONG TERM...MARSILI
AVIATION...FISHER


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