Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 251055
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
555 AM EST THU DEC 25 2014

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

&&

.SYNOPSIS...
ISSUED AT 303 AM EST THU DEC 25 2014

HIGH PRESSURE WILL BUILD INTO THE OHIO VALLEY TODAY...WITH LIGHT
DRIZZLE AND FLURRIES ENDING THIS MORNING. CLOUDS WILL BE SLOWER TO
DEPART...WITH CLEARING NOT COMING UNTIL LATE THIS AFTERNOON INTO THE
EVENING. DRY MILD WEATHER IS ANTICIPATED FRIDAY BEFORE UNSETTLED
WEATHER RETURNS WITH A COLD FRONT MOVING THROUGH THE REGION DURING
THE FIRST HALF OF THE WEEKEND. DRIER AND COOLER CONDITIONS WILL THEN
RETURN TO CENTRAL INDIANA FOR THE FIRST HALF OF NEXT WEEK.

&&

.NEAR TERM /TODAY/...
ISSUED AT 303 AM EST THU DEC 25 2014

LIGHT DRIZZLE OCCASIONALLY MIXED WITH FLURRIES CONTINUE ACROSS THE
REGION EARLY THIS MORNING IN THE BACKWASH OF THE STILL DEEPENING
SURFACE LOW NOW LOCATED NORTH OF THE GREAT LAKES. TEMPS WERE IN THE
LOWER AND MIDDLE 30S AS OF 08Z.

A QUIETER DAY IN STORE FOR CHRISTMAS AS WE FINALLY SAY GOOD RIDDANCE
TO A STORM SYSTEM THAT SEEMED TO BEFUDDLE MODEL GUIDANCE AND
FRUSTRATE METEOROLOGISTS OVER THE LAST SEVERAL DAYS. UPPER TROUGH
AXIS STILL MAKING ITS WAY THROUGH THE REGION...AND NOT LIKELY TO
SHIFT COMPLETELY EAST OF THE HOOSIER STATE UNTIL LATER THIS MORNING.
PATCHY LIGHT DRIZZLE/FLURRIES WILL PERSIST UNTIL THIS HAPPENS AND
POSSIBLY EVEN LINGER WELL INTO THE MORNING OVER THE EASTERN COUNTIES
AS DRIER AIR ALOFT INTERACTS WITH A LINGERING LOW LEVEL INVERSION.
ANY LIGHT PRECIS SHOULD BE DONE BY LATE MORNING AS UPPER RIDGING
QUICKLY BUILDS INTO THE OHIO VALLEY.

THE REMAINING ISSUE FOR TODAY FOCUSES ON HOW LONG THE STRATUS DECK
LINGERS BEFORE THE DRIER AIR CAN WEAKEN AND PUNCH THROUGH THE
INVERSION. CONSIDERING THAT THE BACK EDGE OF THE DECK EXTENDS WEST
OF THE MISSISSIPPI RIVER CURRENTLY...SUSPECT SOME OF THE MODEL
GUIDANCE /OP GFS IN PARTICULAR/ IS BEING TOO PROGRESSIVE IN BREAKING
UP THE CLOUDS. HAVE TRENDED TOWARDS THE RAP/NAM SOLUTIONS WHICH HOLD
ONTO THE LOW CLOUDS WELL INTO THE AFTERNOON WITH SOME CLEARING
TAKING PLACE LATE DAY FROM THE SOUTHWEST. WINDS WILL REMAIN BRISK AS
THE SURFACE PRESSURE GRADIENT SLOWLY RELAXES WITH HIGH PRESSURE
PASSING TO THE SOUTH. EXPECT A STEADY 10-15MPH THROUGH MUCH OF THE
DAY WITH SPORADIC HIGHER GUSTS.

TEMPS...THE LINGERING CLOUDS AS DISCUSSED ABOVE STRONGLY SUPPORT
UNDERCUTTING MOS GUIDANCE WHICH HAS LOOKED TOO WARM THE LAST FEW
DAYS ANYWAYS DESPITE DEVELOPING WARM AFFECTION. KEEPING NORTHEAST
HALF OF THE FORECAST AREA IN THE UPPER 30S WITH LOWER 40S OVER THE
SOUTHWEST WITH SOME SUN DEVELOPING LATE.

&&

.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
ISSUED AT 303 AM EST THU DEC 25 2014

FORECAST CHALLENGES FOCUS ON TEMPS THROUGH THE PERIOD AND PRECIS
CHANCES BEGINNING FRIDAY NIGHT THROUGH EARLY SUNDAY AS A SLOW MOVING
COLD FRONT IMPACTS THE REGION.

PLEASANT DAY BY LATE DECEMBER STANDARDS COMING FOR FRIDAY AS THE
OHIO VALLEY REMAINS WEDGED BETWEEN HIGH PRESSURE CENTERED OVER THE
CAROLIN AS AND THE AFOREMENTIONED COLD FRONT TRACKING INTO THE
CENTRAL PLAINS AND WESTERN GREAT LAKES. SUNNY START TO THE DAY WITH
MID AND HIGH LEVEL CLOUDS INCREASING BY AFTERNOON. COULD EVEN SEE
STRATUS RETURN INTO WABASH VALLEY BY LATE DAY AS DEEPER MOISTURE IS
DRAWN NORTH INTO THE REGION AND INVERSION ATTEMPTS TO REESTABLISH.
COMBINATION OF A MODEST SURFACE PRESSURE GRADIENT AND A 35-40KT LOW
LEVEL JET WILL CONTRIBUTE TO A BREEZY AFTERNOON WITH GUSTS TO NEAR
25MPH.

LOWER CLOUD DECK WILL FULLY REDEVELOP OVER MOST OF THE REGION FRIDAY
NIGHT AS LOW PRESSURE TRACKS INTO THE GREAT LAKES AND THE FRONT
APPROACHES. BRIEF PERIOD OF MODEST IS ENTROPIC LIFT NOTED THROUGH
290K FRIDAY EVENING BEFORE SHIFTING NORTH OVERNIGHT WITH THE LOW
MOVING INTO WESTERN MICHIGAN. THE LIFT MAY BE ENOUGH TO GENERATE A
FEW LIGHT SHOWERS OR DRIZZLE AT THE VERY LEAST AS EARLY AS FRIDAY
EVENING IN OUR WESTERN COUNTIES.

DEEPER MOISTURE AND AN INCREASE IN FORCING ALOFT WILL BRING
SCATTERED SHOWERS INTO THE AREA AROUND DAYBREAK SATURDAY...EXPANDING
ACROSS THE ENTIRE FORECAST AREA THROUGH THE COURSE OF THE DAY.
PRECIS AMOUNTS WILL LARGELY BE A QUARTER INCH OR LESS...BUT EXPECTED
COVERAGE SUPPORTS 50-60 POPS SATURDAY/SATURDAY NIGHT WITH HIGHEST
POPS OVER SOUTHERN HALF OF THE FORECAST AREA WHERE BETTER LIFT WILL
RESIDE. COLDER AIR WILL SEEP INTO THE REGION AS THE FRONT SHIFTS
SOUTH OF THE OHIO RIVER SATURDAY NIGHT. CRITICAL THICKNESSES AND
MODEL SOUNDINGS SHOW LOW LEVEL BECOMING SUFFICIENT TO SUPPORT LIGHT
SNOW MIXING IN BEFORE THE PRECIS COMES TO AN END.

TEMPS...LOW LEVEL THERMALS AND EXPECTED IMPACTS FROM CLOUDS/PRECIS
AT VARIOUS POINTS DURING THE SHORT TERM LARGELY SUPPORT LEANING
TOWARDS COOL END OF GUIDANCE DURING THE DAY. THIS WILL RESULT IN
HIGH TEMPS IN THE UPPER 40S BOTH FRIDAY AND SATURDAY...POSSIBLY EVEN
LOWER 50S OVER SOUTHERN FORECAST AREA FRIDAY. TRENDED TOWARDS MAVIS
FOR LOWS THROUGH THE PERIOD.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
ISSUED AT 325 AM EST THU DEC 25 2014

THE INITIALIZATION FROM THE REGIONAL MODEL WILL BE ACCEPTED.
FORECAST CONFIDENCE IS HIGH MOST OF THE PERIOD. IT BECOMES
MODERATE WEDNESDAY.

EARLY IN THE PERIOD THE EUROPEAN...GFS...AND GFS ENSEMBLE MODELS ALL
HAVE THE REGIONS WEATHER CONTROLLED BY HIGH PRESSURE. THEY ALSO
FORECAST FAIRLY SIMILAR 850 MILLIBAR TEMPERATURES. WITH THEM ALL
PREDICTING ABOUT THE SAME THING...PROBABLY THAT WILL HAPPEN.

WEDNESDAY LARGER DIFFERENCES ARISE. THE DIFFERENCES ARE NOT SO
EXTREME AS TO MAKE A TOTAL DIFFERENCE IN THE WEATHER INDIANA GETS.
STILL...THE RANGE OF POSSIBILITIES IS GREATER THAN EARLIER IN THE
WEEK

&&

.AVIATION /DISCUSSION FOR THE 251200 TAF ISSUANCE/...

ISSUED AT 555 AM EST THU DEC 25 2014

MVFR CEILINGS WILL BE WIDESPREAD DURING THE MORNING. CLOUDS SHOULD
BECOME SCATTERED FROM THE WEST BY MID AFTERNOON AS A RIDGE MOVES IN
FROM THE WEST. AFTER RESIDUAL CLOUDS DISSIPATE AROUND SUNDOWN MOSTLY
CLEAR SKIES WILL PREVAIL.

WINDS CAN BE EXPECTED TO BACK FROM WEST TO SOUTH TODAY AND STAY
SOUTH OVERNIGHT. DAYTIME SPEEDS ARE GOING TO BE MOSTLY 10-15 KNOTS.
SOME GUSTS TO 20 KNOTS CAN BE EXPECTED IN THE AFTERNOON. WINDS
OVERNIGHT ARE LIKELY TO STAY BELOW 10 KNOTS...BUT SHOULD BE
SUFFICIENT TO PREVENT FOG.


&&

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

$$

SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....JK
AVIATION...JK

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