Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 020440
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
1140 PM EST SUN MAR 1 2015

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

&&

.SYNOPSIS...
ISSUED AT 347 PM EST SUN MAR 1 2015

SNOW WILL COME TO AN END THIS EVENING ACROSS THE AREA AS A LOW
PRESSURE SYSTEM PULLS OFF TO THE EAST. AN AREA OF HIGH PRESSURE
WILL PROVIDE A BRIEF BREAK FROM SIGNIFICANT WEATHER BEFORE A
STRONG LOW PRESSURE SYSTEM DEVELOPS ACROSS THE PLAINS AND MOVES
THROUGH THE GREAT LAKES TOMORROW NIGHT INTO WEDNESDAY. THIS SYSTEM
APPEARS LIKELY TO BRING AT LEAST A PERIOD OF FREEZING RAIN AND
SLEET...MIXING AT TIMES...LATE MONDAY NIGHT INTO TUESDAY.
PRECIPITATION WILL CHANGE TO ALL RAIN TUESDAY AFTERNOON AND
EVENING...WITH SOME LIGHT SNOW POSSIBLE LATE TUESDAY NIGHT INTO
WEDNESDAY. FLOODING WILL BE A CONCERN AS AN INCH OR MORE OF
RAINFALL APPEARS POSSIBLE COUPLED WITH DEEPLY FROZEN GROUND AND A
DEEP SNOWPACK WITH UP TO AN INCH OF LIQUID EQUIVALENT. QUIETER BUT
COLDER WEATHER CAN BE EXPECTED LATER IN THE WEEK.

&&

.NEAR TERM /REST OF TONIGHT/...

ISSUED AT 926 PM EST SUN MAR 1 2015

UPDATE...
PRECIPITATION HAS COME TO AN END ACROSS CENTRAL INDIANA...AND HIGH
PRESSURE IS SLOWLY BUILDING INTO THE AREA. MOSTLY CLOUDY SKIES
WILL LINGER THROUGH MIDNIGHT...WITH GRADUAL CLEARING FROM
NORTHWEST TO SOUTHEAST AFTER THAT. RADIATIONAL COOLING LATE IN THE
NIGHT WILL RESULT IN LOWS DIPPING INTO THE TEENS. UPDATED GRIDS
HAVE BEEN SENT.

PREVIOUS DISCUSSION...
EXPECT TEMPS TO GET DOWN WELL INTO THE TEENS...AND WOULD NOT BE
SURPRISED TO SEE A FEW SINGLE DIGIT READINGS DEPENDING ON HOW LOW
DEWPOINTS CAN GET ACROSS THE NORTH. THIS IS GENERALLY AT OR
SLIGHTLY BELOW CONSENSUS NUMBERS.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
ISSUED AT 347 PM EST SUN MAR 1 2015

MAIN FOCUS DURING THE SHORT TERM WILL BE THE SYSTEM IMPACTING THE
AREA LATE MONDAY NIGHT THROUGH WEDNESDAY.

THERMAL PROFILES APPEAR SUPPORTIVE OF FROZEN OR FREEZING
PRECIPITATION ACROSS THE AREA LATE MONDAY NIGHT AND TUESDAY
MORNING...ALTHOUGH WITH EXTREMELY STRONG WARM ADVECTION ON THE
BACK OF A PROGGED 70KT LOW LEVEL JET...PRECIPITATION LATE TUESDAY
MORNING INTO THE AFTERNOON WILL RAPIDLY CHANGE OVER TO RAIN. MAY
REQUIRE SOME SORT OF HEADLINE FOR THE TUESDAY MORNING COMMUTE BUT
WITH SOME UNCERTAINTY REMAINING AND AN EVENT STILL ONGOING/WINDING
DOWN WILL HOLD OFF ON ADDITIONAL HEADLINES FOR NOW AND RELY ON
HWO/GRAPHICS TO HIGHLIGHT NEXT THREAT.

IN ADDITION TO THE WINTRY PRECIPITATION THREAT...FLOODING MAY ALSO
BECOME AN ISSUE AS PRECIPITABLE WATER VALUES PUSHING THE 99TH
PERCENTILE...OR MORE THAN 2 STANDARD DEVIATIONS ABOVE
CLIMATOLOGICAL NORMAL FOR THE TIME OF YEAR...WILL ACCOMPANY THIS
SYSTEM...COMBINED WITH A WIDESPREAD SNOWPACK WITH LIQUID
EQUIVALENT APPROACHING ONE INCH IN SPOTS...WHICH WILL BE RAPIDLY
MELTING AS THE EVENT WEARS ON.

THE GROUND IS ALSO FROZEN FAIRLY DEEPLY AND WILL BE MUCH SLOWER TO
WARM THAN THE AIR OBVIOUSLY...WHICH MEANS THE VAST MAJORITY OF
RAIN FALLING WITH THE SYSTEM WILL BE RAPIDLY CONVERTED TO RUNOFF.

ADDITIONALLY...URBAN FLOODING MAY BE A PROBLEM AS PARTIALLY MELTED
SNOW CLOGS STREET DRAINS AND ALLOWS RUNOFF TO POOL ON ROADS.

PROBABILISTIC QPF PROGS PLACE THE HIGHEST THREAT OF ONE INCH OR
MORE OF RAINFALL ACROSS NORTHERN KENTUCKY...BUT EVEN RAINFALL
APPROACHING ONE INCH MAY CAUSE SIGNIFICANT PROBLEMS ACROSS THE AREA.

LINGERING PRECIPITATION MAY CHANGE TO SNOW LATE TUESDAY NIGHT INTO
WEDNESDAY...BUT LITTLE ACCUMULATION APPEARS POSSIBLE AT THIS TIME.

USED CONSENSUS NUMBERS FOR TEMPERATURES GENERALLY...WITH SOME
MINOR TWEAKS.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
ISSUED AT 240 PM SUN MAR 1 2015

LOW CHANCES OF SNOW SHOULD LINGER INTO WEDNESDAY EVENING OVER
CENTRAL AND SOUTHEAST SECTIONS AS THE EURO AND GEMNH HAVE TRENDED A
LITTLE SLOWER WITH A FRONTAL SYSTEM AND UPPER DISTURBANCE TO OUR
SOUTHEAST.  OTHERWISE...THE REST OF THE LONG TERM WILL BE DRY AS A
COUPLE OF HIGH PRESSURE SYSTEMS MOVE EAST ACROSS OUR REGION.

THURSDAY WILL BE QUITE COLD WITH 850 MB TEMPERATURES AS LOW AS -17
CELSIUS. BUT TEMPERATURES WILL MODERATE SOME OVER THE REST OF THE
LONG TERM AS MODELS INDICATE 850 MB TEMPERATURES NEAR OR SLIGHTLY
BELOW ZERO.  IN MOST CASES A MODEL BLEND ON TEMPERATURES SEEM
REASONABLE.

&&

.AVIATION /DISCUSSION FOR THE 020600Z TAF ISSUANCE/...

ISSUED AT 1145 PM EST SUN MAR 1 2015

THE WIDESPREAD MVFR CEILINGS FROM EARLIER THIS EVENING ACROSS ARE
STARTING TO IMPROVE TO VFR ALREADY VERY EARLY THIS MORNING. AFTER
LOOKING AT CONDITIONS UPSTREAM APPEARS KLAF WILL REMAIN AT VFR FOR
THE REST OF THE PERIOD. THEN ALL SITES WILL SCATTER OUT IN THE LOW
LEVELS FOR GOOD BY 08-11Z THIS MORNING. LIGHT NORTHWEST WINDS WILL
SHIFT TO THE NORTHEAST EARLY THIS AFTERNOON AS HIGH PRESSURE BUILDS
INTO OUR REGION.

MID LEVEL CLOUDS WILL BEGIN TO INCREASE ACROSS THE AREA AGAIN
LATER THIS AFTERNOON AND EVENING AS A STRONG LOW PRESSURE SYSTEM
ADVANCES TOWARD THE AREA. PUT IN A MVFR GROUP AT THE TAIL OF THE
THE KIND TAF PERIOD AROUND 10Z FOR A WINTRY MIX...-FZRAPL WITH
MVFR CEILINGS AND VISIBILITIES. CONDITIONS ARE EXPECTED TO
RAPIDLY DETERIORATE AFTER 12Z TUESDAY WITH A WIDESPREAD AREA OF
HEAVY WINTRY MIX PRECIPITATION FORECAST FOR CENTRAL INDIANA ON TUESDAY.
THIS IS OUTSIDE OF THE OTHER TAF FORECAST PERIODS BUT LIKELY WILL BE
INCLUDED IN SUBSEQUENT AVIATION FORECAST UPDATES.

&&

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

$$

SYNOPSIS...NIELD
NEAR TERM...NIELD/TDUD
SHORT TERM...NIELD
LONG TERM...JH
AVIATION...SMF

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