Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 211941
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
240 PM EST SUN DEC 21 2014

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

&&

.SYNOPSIS...
ISSUED AT 301 AM EST SUN DEC 21 2014

A LOW PRESSURE SYSTEM WILL BRING PRECIPITATION TO CENTRAL INDIANA
MONDAY THROUGH WEDNESDAY. AFTER A DRY CHRISTMAS...CHANCES FOR
PRECIPITATION WILL RETURN FRIDAY WITH A WEAKER SYSTEM. WARM AIR
AHEAD OF THE FIRST SYSTEM COULD BRING THE WARMEST READINGS OF
DECEMBER ON TUESDAY...THEN TEMPERATURES WILL RETURN TO CLOSER TO
AVERAGE BY CHRISTMAS.

&&

.NEAR TERM.../REST OF TODAY/...
ISSUED AT 1027 AM EST SUN DEC 21 2014

PATCHES OF LOW CLOUDS LINGER ACROSS THE LOCAL AREA LATE THIS
MORNING...ESPECIALLY OVER THE NORTHWESTERN/NORTHERN ZONES. THESE
CLOUDS HAVE BEEN HOLDING STEADY OR SLOWLY RETREATING OVER THE PAST
COUPLE OF HOURS. SHORT TERM MODELS SUGGEST THE AIR MASS NEAR THE
CLOUD LEVEL WILL BE SLOWLY DRYING OUT TODAY...SO DON/T THINK THE LOW
CLOUDS WILL EXPAND ALL THAT MUCH TODAY.

CURRENT FORECAST HIGHS STILL LOOK GOOD. NO UPDATES PLANNED AT THIS
TIME.

PREVIOUS DISCUSSION FOLLOWS.

SKIES HAVE CLEARED ACROSS A GOOD PORTION OF CENTRAL INDIANA EARLY
THIS MORNING...BUT ADDITIONAL LOW CLOUDS WERE NEAR THE
ILLINOIS/INDIANA BORDER AND MOVING SLOWLY EAST.

CLOUD COVER WILL BE TOUGH TO PIN DOWN TODAY AND ONCE AGAIN
CONFIDENCE IS LOW IN THE DETAILS. LOW CLOUDS WILL MARCH INTO WESTERN
AND NORTHWESTERN SECTIONS OF THE AREA THIS MORNING. HOWEVER DRIER
AIR WILL FLOW INTO THE AREA AS WINDS INCREASE OUT OF THE SOUTHEAST.

FOR NOW WILL GO MOSTLY CLOUDY ACROSS THE NORTHWEST FORECAST
AREA...WITH SKIES REMAINING/BECOMING PARTLY CLOUDY ELSEWHERE.
ADJUSTMENTS WILL LIKELY HAVE TO BE MADE LATER THIS MORNING AS THE
EVOLUTION OF THE CLOUDS BECOMES CLEARER.

TEMPERATURES HAVE COOLED MORE THAN EXPECTED EARLY THIS MORNING DUE
TO THE PARTIAL CLEARING. THIS COLD START WILL HELP KEEP TEMPERATURES
BELOW MAV MOS AND CLOSER TO THE MET MOS TODAY.

&&

.SHORT TERM.../TONIGHT THROUGH TUESDAY NIGHT/
ISSUED AT 301 AM EST SUN DEC 21 2014

FOCUS IS ON CHANCES FOR PRECIPITATION THROUGH THE PERIOD. MODELS ARE
SHOWING DIFFERENCES AS WOULD BE EXPECTED WITH THE INCOMING SYSTEM
NOT FULLY SAMPLED YET. CANADIAN LOOKS TOO STRONG WITH THE
SYSTEM...WHILE THE LARGER CHANGE IN SOLUTIONS BETWEEN THE 12Z/00Z
ECMWF LEADS TO LOWER CONFIDENCE IN ITS SOLUTION THIS RUN. WILL USE A
BLEND OF REMAINING MODELS.

CLOUDS WILL INCREASE TONIGHT AS THE SYSTEM APPROACHES FROM THE WEST.
WILL GO A LITTLE WARMER THAN MAV MOS MOST AREAS.

ON MONDAY ISENTROPIC LIFT INCREASES DURING THE AFTERNOON. HOWEVER
DEEPER MOISTURE WILL BE SLOWER TO RETURN THANKS IN PART TO SOUTHEAST
WINDS IN THE LOWER LEVELS. WILL KEEP THE MORNING DRY AND GO WITH
SLIGHT CHANCE TO CHANCE POPS IN THE AFTERNOON. WITH THE CLOUDS AND
SOUTHEAST FLOW...MOS LOOKS TOO WARM FOR HIGHS. WILL CUT SOME.

MONDAY NIGHT AND TUESDAY FORCING RAMPS UP WITH SURFACE FRONT MOVING
INTO THE AREA...850MB WINDS APPROACHING 50KT...AND AN UPPER JET
MOVING IN. THUS WENT LIKELY POPS MOST AREAS BY LATE MONDAY NIGHT AND
LIKELY TO CATEGORICAL POPS ON TUESDAY.

CONTINUED LIKELY TO CATEGORICAL POPS TUESDAY NIGHT AS A SURFACE LOW
RIDES ALONG THE FRONT TOWARD CENTRAL INDIANA. LOOKS LIKE COLDER AIR
WILL BE SLOWER TO ARRIVE THAN PREVIOUSLY THOUGHT...SO WENT ALL RAIN
THROUGH TUESDAY NIGHT.

THE SYSTEM LOOKS TO BRING ENOUGH WARM UP INTO THE AREA ON TUESDAY
FOR HIGHS IN THE LOWER TO MIDDLE 50S...WHICH WILL BE THE WARMEST AIR
THIS MONTH ACROSS THE AREA.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
ISSUED AT 240 PM EST SUN DEC 21 2014

MAIN FOCUS FOR THE EXTENDED WILL BE ON PRECIPITATION POTENTIAL FOR
THE TAIL END OF A STRONG CHRISTMAS EVE SYSTEM ALONG WITH A FRIDAY
AND FRIDAY NIGHT SYSTEM.

MODELS AND ENSEMBLES AGREE FRONTAL SYSTEM WILL BE MOVING TO THE EAST
COAST CHRISTMAS EVE NIGHT WHICH SHOULD BRING AN END TO THE MIDWEEK
PRECIPITATION EVENT. PARTIAL MODEL THICKNESSES SUGGEST IT SHOULD BE
ALL SNOW WEDNESDAY NIGHT AND ENDING OVERNIGHT FROM EAST TO WEST.
SO...CHANCE POPS LOOK OK WITH LIKELY ONLY A MINOR ACCUMULATION.

UPPER RIDGING WILL RESULT IN DRY WEATHER WITH WARMING TEMPERATURES
LATE WEEK BEFORE ANOTHER FRONTAL SYSTEM BRINGS A SMALL CHANCE OF
RAIN ON FRIDAY AND SNOW FRIDAY NIGHT. AGAIN...ANY ACCUMULATION LOOKS
TO BE MINOR AT BEST. THE REST OF THE EXTENDED LOOKS DRY AS SURFACE
HIGH PRESSURE BUILDS IN FROM THE PLAINS.

SHOULD SEE SOME GUSTY WINDS MAINLY THROUGH FRIDAY NIGHT AS SURFACE
PRESSURE GRADIENT IS TIGHT. MEANWHILE...EXPECTED CLOUD COVER AND LOW
LEVEL THERMAL PROGS SUGGEST REGIONAL BLEND LOOKS GOOD WITH ABOVE
NORMAL HIGHS MAINLY IN THE 40S ON THURSDAY AND FRIDAY AND COLDER
TEMPERATURES FOR THE WEEKEND WITH HIGHS IN THE LOWER TO MID 30S.
OVERNIGHT LOWS SHOULD MOSTLY BE IN THE 30S CHRISTMAS EVE NIGHT AND
THURSDAY NIGHT AND THE 20S AFTER THAT.

&&

.AVIATION /DISCUSSION FOR 211800Z TAF ISSUANCE/...
ISSUED AT 1208 PM EST SUN DEC 21 2014

VFR CONDITIONS SHOULD CONTINUE THROUGH TONIGHT WITH MVFR CEILINGS
INCREASING AFTER 14Z MONDAY AS A WARM FRONT APPROACHES FROM THE
SOUTHWEST.

WINDS WILL BE SOUTHEAST TO NEAR 10 KNOTS THIS AFTERNOON...6 KNOTS OR
LESS AFTER 00Z TONIGHT AND 10 KNOTS OR MORE AFTER 14Z MONDAY.

&&

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

&&

$$

SYNOPSIS...50
NEAR TERM...50/JAS
SHORT TERM...50
LONG TERM....MK
AVIATION...MK

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