Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 251847
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
245 PM EDT WED MAR 25 2015

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

&&

.SYNOPSIS...
ISSUED AT 237 AM EDT WED MAR 25 2015

A WEAK COLD FRONT WILL PASS INDIANA TODAY. OVERNIGHT A LOW
PRESSURE SYSTEM WILL CROSS THE SOUTHERN PART OF OUR STATE. THIS
SYSTEM WILL BE STRONG ENOUGH TO KEEP CONTROL OF THE WEATHER
THROUGH THURSDAY NIGHT AS IT HEADS OFF THE EAST.

FRIDAY A HIGH PRESSURE SYSTEM WILL MOVE IN AND DOMINATE HOOSIER
WEATHER INTO SUNDAY. NEXT...LOW PRESSURE AND AN ASSOCIATED COLD
FRONT SHOULD MOVE BY. AS MONDAY GOES ON...MORE HIGH PRESSURE IS
PREDICTED TO ARRIVE FROM THE WEST.

&&

.NEAR TERM /REST OF TODAY/...
ISSUED AT 1005 AM EDT WED MAR 25 2015

COLD FRONT WAS ACROSS SOUTHEAST INDIANA AND WILL STALL ACROSS
NORTHERN KENTUCKY PER MODELS.  RAIN SHOWERS HAVE MOVED OFF WELL TO
THE EAST...BUT SATELLITE INDICATES LOTS OF POST FRONTAL CLOUDS WERE
ACROSS MUCH OF THE AREA.  RUC SOUNDINGS INDICATE LOW CLOUDS SHOULD
BREAK UP BY LATE AFTERNOON. I EXPECT IT TO BE MOSTLY CLOUDY THROUGH
EARLY AFTERNOON AND THEN PARTLY CLOUDY BY LATE AFTERNOON.

GIVEN THAT COLD ADVECTION WAS ALREADY OCCURRING AND CLOUDS SHOULD
PERSIST THROUGH EARLY TO MID AFTERNOON...WILL LOWER TEMPERATURES A
LITTLE ACROSS NORTH AND CENTRAL SECTIONS.  WILL LEAVE THE SOUTH
UNCHANGED AS THERE WILL BE A LITTLE MORE SUN THERE AND THEY WILL
ALSO BE CLOSER TO THE COLD FRONT.

IT LOOKS LIKE HIGHS TODAY WILL BE IN THE 50S OVER NORTH AND CENTRAL
SECTIONS TO THE MIDDLE AND UPPER 60S FAR SOUTH.

&&

.SHORT TERM /TONIGHT THROUGH SATURDAY/...

ISSUED AT 237 AM EDT WED MAR 25 2015

THE MOST DIFFICULT PROBLEM IS TEMPERATURES.

THE MODELS CONCUR ABOUT STRONG COLD ADVECTION DEVELOPING LATE
TONIGHT AND CONTINUING THURSDAY. GRADIENTS ARE GOING TO BE TIGHT. A
TIMING ERROR OF A FEW HOURS COULD MAKE A BIG DIFFERENCE.

THIS RELATIVELY UNUSUAL SITUATION IS NOT THE SORT OF THING MOS IS
BEST AT. SOMETHING FROM A GOOD DETERMINISTIC MODELS IS APT TO BE
BETTER. GIVEN CONSHORT IS A GOOD DETERMINISTIC MODEL IT WILL BE USED.

AFTER THURSDAY TEMPERATURE GRADIENTS WILL WEAKEN AND NORMAL DIURNAL
PATTERNS BECOME BETTER ESTABLISHED. THIS IS WHERE MOS COMES INTO ITS
OWN. THE MAV WILL BE USED BECAUSE OF ITS LONGER TRAINING PERIOD.

ALL THE GUIDANCE POINTS TO RAIN TONIGHT...ENDING FROM THE
NORTHWEST THURSDAY...AND THEN A DRY PERIOD. CLOUDS ARE APT TO HANG
ON AT LEAST INTO FRIDAY AS WE RETAIN A SLIGHT CYCLONIC FLOW ACROSS
THE EASTERN LAKES.

CAPES ARE JUST HIGH ENOUGH TO MENTION THUNDER IN THE FORECAST
TONIGHT. THE RAIN MAY BE HEAVY AT TIMES IN THE SOUTHERN CWA THANKS
TO PROXIMITY TO THE WELL DEVELOPED SURFACE LOW WHILE A RATHER STRONG
WAVE PASSES ALOFT.

THICKNESS PATTERNS THURSDAY SUGGEST THE RACE WILL BE ON WHETHER THE
PRECIPITATION WILL END BEFORE IT CHANGES TO SNOW. GIVEN THE
UNCERTAINTY ABOUT THIS A CHANCE OF SNOW WILL BE INCLUDED IN THE
FORECAST.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...

ISSUED AT 245 PM EDT WED MAR 25 2015

12Z ECMWF AND GFS SUGGEST A CHANGE IN THE PATTERN OVER THE
CONTINENTAL UNITED STATES BY EARLY TO MID WEEK OF NEXT WEEK WITH THE
ALL TOO FAMILIAR WESTERN RIDGE AND EASTERN TROUGH DUO DEPARTING IN
FAVOR OF MORE ZONAL FLOW.

THE EXTENDED WILL START OFF COOL AND DRY SATURDAY NIGHT UNDER THE
INFLUENCE OF SURFACE HIGH PRESSURE. HOWEVER...THE HIGH WILL SHIFT TO
THE SOUTHEASTERN STATES ON SUNDAY ALLOWING FOR RETURN FLOW OFF THE
GULF AHEAD OF AN APPROACHING COLD FRONT. THIS SETUP WILL ALLOW FOR
WARMING TEMPERATURES BUT CHANCES OF RAIN SUNDAY AND SUNDAY NIGHT PER
THE REGIONAL BLEND. THE MODELS DIVERGE AFTER THAT...ALTHOUGH
GENERALLY UPPER FLOW WILL BECOME MORE ZONAL. IN ADDITION...ANOTHER
FRONTAL SYSTEM ON THE BACK SIDE OF THIS HIGH WILL BE APPROACHING
MIDWEEK ALLOWING FOR EVEN WARMER TEMPERATURES ALONG WITH RAIN
CHANCES. COULD SEE HIGHS IN THE 60S BY TUESDAY PER REGIONAL BLEND.

&&

.AVIATION /DISCUSSION FOR THE 251800Z TAF ISSUANCE/...

ISSUED AT 1230 PM EDT WED MAR 25 2015

MVFR CONDITIONS EXPECTED TO IMPROVE TO VFR 19Z-20Z. A COLD FRONT
WILL STALL ACROSS SOUTHERN INDIANA THIS AFTERNOON. THEN...A WAVE OF
LOW PRESSURE WILL LIFT NORTHEAST ALONG THE FRONT TONIGHT. THE WAVE
ALONG WITH DEEPENING MOISTURE SHOULD RESULT IN MODERATE RAIN ACROSS
ALL BUT LAF AFTER 06Z TONIGHT. BMG COULD EVEN SEE SOME HEAVY
RAIN...IFR CONDITIONS AND PERHAPS EMBEDDED THUNDERSTORMS.
HOWEVER...DO NOT PLAN ON PUTTING THAT IN THE TAFS UNTIL IT GETS
CLOSER...SO TIMING CAN BE PINNED DOWN BETTER. LAF ON THE OTHER
HAND...MAY ONLY SEE LIGHT RAIN. THE RAIN SHOULD MOVE OUT AFTER 12Z.
WOULD NOT RULE OUT A BRIEF SWITCH TO SNOW BEFORE ENDING AT LAF...BUT
CONFIDENCE NOT HIGH ENOUGH TO MENTION SNOW THERE AT THIS TIME.
CONDITIONS SHOULD IMPROVE TO VFR AFTER 16Z TOMORROW.

WINDS WILL VEER FROM WEST TO NORTH OVERNIGHT. THE GUSTS SHOULD END
AT IND AND BMG EARLY TODAY AS THE LOW LEVEL JET SHIFTS EAST TO THE
APPALACHIANS...AND THE SURFACE PRESSURE GRADIENT WEAKENS.
HOWEVER...WINDS WILL PICK UP A BIT TO UP TO 10 KNOTS OVERNIGHT AS
THE GRADIENT TIGHTENS IN THE WAKE OF THE SURFACE WAVE MOVING PAST.

&&

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

$$

SYNOPSIS...JK
NEAR TERM...JH
SHORT TERM...JK
LONG TERM....MK
AVIATION...MK

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