Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 180754
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
254 AM EST THU DEC 18 2014

.UPDATE...
THE SYNOPSIS...NEAR TERM AND SHORT TERM SECTIONS HAVE BEEN UPDATED BELOW.

&&

.SYNOPSIS...
ISSUED AT 252 AM EST THU DEC 18 2014

HIGH PRESSURE IS EXPECTED ACROSS THE AREA THROUGH THE END OF THE
WEEK. THE NORTHERN FRINGES OF A LOW PRESSURE SYSTEM PASSING THROUGH
THE GULF COAST STATES MAY AFFECT PARTS OF THE AREA BY THE END OF
WEEK. A SIGNIFICANT LOW PRESSURE SYSTEM MAY MOVE INTO THE AREA BY
THE EARLY TO MIDDLE PARTS OF NEXT WEEK.

&&

.NEAR TERM /TODAY/...
ISSUED AT 252 AM EST THU DEC 18 2014

WEAK UPPER WAVE CAUSING SOME SNOW OVER THE PLAINS EARLY THIS MORNING
IS EXPECTED TO MOVE INTO THE LOCAL AREA THIS AFTERNOON AND DAMPEN
OUT UNDER THE CONFLUENT FLOW OVER THE NORTHEAST PARTS OF THE
COUNTRY. LIFT CONTINUES TO LOOK RATHER WEAK AT THIS TIME...ALTHOUGH
THE PRECIPITATION BEARING LAYER NEARLY SATURATES. THERE IS STILL
QUITE A BIT OF DRY AIR UNDER THE PRECIPITATION BEARING LAYER...SO
THIS STILL LOOKS LIKE A FLURRY/TRACE EVENT AT THIS TIME. SOME OF THE
FINER SCALE SHORT TERM GUIDANCE IS MORE AGGRESSIVE WITH THE LIFT
THIS AFTERNOON...SUGGESTING A DUSTING OF SNOW IS POSSIBLE THIS
AFTERNOON. FOR NOW...WILL STICK WITH THE FLURRY MENTION AND LATER
SHIFTS WILL NEED TO MONITOR THE PRECIPITATION TRENDS AS THE DAY GOES
BY.

GIVEN THE CLOUD COVER TODAY...THE GFS MOS HIGHS FOR TODAY LOOK A
LITTLE WARM. WILL NUDGE THE HIGHS DOWN A COUPLE OF DEGREES.

&&

.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
ISSUED AT 252 AM EST THU DEC 18 2014

MODEL DATA SUGGEST THERE MAY STILL SOME REMNANT ENERGY MOVING
THROUGH THE AREA THIS EVENING ASSOCIATED WITH TODAY/S
DISTURBANCE...SO WILL EXTEND THE FLURRY MENTION INTO THE EVENING
HOURS TONIGHT.

OTHERWISE...A SPLIT FLOW IS EXPECTED TO DEVELOP BY THE END OF THE
WEEK AS THE UPPER BLOCK OVER SOUTHERN CANADA BREAKS DOWN. A SOUTHERN
STREAM DISTURBANCE IS EXPECTED TO SCOOT ALONG THE GULF COAST
STATES...WHILE A DRIER NORTHERN STREAM SYSTEM DIGS INTO THE GREAT
LAKES BY SATURDAY. OPERATIONAL GUIDANCE IS IN PRETTY GOOD AGREEMENT
IN KEEPING THE MAIN PRECIPITATION THREAT TIED UP IN THE SOUTHERN
STREAM AND WELL SOUTH OF THE LOCAL AREA. THERE ARE SOME ENSEMBLES
THAT DRAW ENOUGH MOISTURE NORTH FOR A THREAT FOR LIGHT SNOW AND
MINOR ACCUMULATIONS OVER THE SOUTHERN/SOUTHEASTERN ZONES LATE FRIDAY
NIGHT INTO SATURDAY. TO COVER THIS POSSIBILITY...WILL KEEP SOME
CHANCE POPS GOING FOR LIGHT SNOW DURING THOSE PERIODS OVER ABOUT THE
SOUTHEAST HALF OF THE FORECAST AREA.

GIVEN THE DEGREE OF CLOUD COVER EXPECTED OVER THE NEXT COUPLE OF
DAYS...WILL CONTINUE TO NARROW THE DIURNAL RANGE OF THE GFS MOS
TEMPERATURE GUIDANCE THROUGH THE PERIOD.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
ISSUED AT 135 PM EST WED DEC 17 2014

THE INITIALIZATION FROM THE REGIONAL MODEL WILL BE ACCEPTED...BUT
THIS IS A VERY LOW CONFIDENCE FORECAST.

THE EUROPEAN MODEL AND THE GFS BOTH DEVELOP VERY STRONG SYSTEMS
ALOFT AND AT THE SURFACE BY MIDWEEK.  WITH SUCH SYSTEMS EVEN A SMALL
DIFFERENCE IN LOCATION COULD HAVE A BIG IMPACT ON THE SENSIBLE
WEATHER.

DIFFERENCES BETWEEN THE MODELS ARE GREAT. DEPENDING ON WHAT IS
CORRECT...INDIANA COULD HAVE A MAJOR WINTER STORM OR A MUCH LESSER
EVENT THE MIDDLE OF NEXT WEEK. IT PROBABLY WONT BE POSSIBLE TO MAKE
A HIGH CONFIDENCE FORECAST UNTIL SUNDAY OR EVEN MONDAY. UNTIL THEN
THE BEST STRATEGY MAY BE TO PLAN FOR THE WORST AND HOPE FOR THE BEST.

&&

.AVIATION /DISCUSSION FOR 180600Z TAF ISSUANCE/...

ISSUED AT 1200 AM EST THU DEC 18 2014

MVFR STRATUS DECK WILL PREVAIL THROUGH THE ENTIRE PERIOD.

MVFR CONDITIONS WILL CONTINUE THROUGH THE OVERNIGHT...THEN EXPECT
ONLY A VERY GRADUAL IMPROVEMENT IN CEILINGS TO HIGHER END MVFR BY
LATE THIS MORNING. THE INVERSION STRENGTHENS AGAIN BY EARLY THIS
EVENING WITH ALL SITES EXPECTED TO MAINTAIN AN MVFR STRATUS DECK.
LEANED WITH NAM GUIDANCE WHICH MORE ACCURATELY DEPICTS THIS
HAPPENING AS OPPOSED TO THE OVERLY OPTIMISTIC MAV/GFS WHICH IS
COMMON DURING THIS TIME OF YEAR. THOUGH THE NAM HAS BEEN SLIGHTLY
MORE OPTIMISTIC THIS MODEL RUN ABOUT SEEING A FEW SITES WITH LOW
END VFR CEILINGS LATE IN THE PERIOD. WILL STICK WITH PERSISTENCE
FORECASTING WITH THIS ISSUANCE AND WHETHER TO GO VFR LATER TODAY
MAY BE DECIDED WITH SUBSEQUENT AVIATION FORECASTS...HOWEVER NOT AT
THIS TIME.

W/NW WINDS 8KT OR LESS THOUGH THE ENTIRE PERIOD.


&&

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

$$

SYNOPSIS...JAS
NEAR TERM...JAS
SHORT TERM...JAS
LONG TERM...JK
AVIATION...SMF

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