FXUS63 KIND 050854
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
354 AM EST SUN FEB 5 2012

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

&&

.SYNOPSIS...

CLOUDS WILL DEPART EARLY THIS MORNING WITH FOG BURNING OFF THROUGH
THE MORNING AS HIGH PRESSURE BUILDS INTO CENTRAL INDIANA. THE HIGH
WILL BRING DRY WEATHER AND MAINLY CLEAR SKIES THROUGH TUESDAY. A
WEAK UPPER LEVEL DISTURBANCE WILL PROVIDE A CHANCE FOR LIGHT RAIN
AND SNOW TUESDAY NIGHT AND WEDNESDAY. THE EXPANSION OF A BROAD UPPER
LEVEL TROUGH WILL SIGNAL A SHIFT TO COLDER TEMPERATURES FOR LATE
WEEK AND INTO NEXT WEEKEND.

&&

.NEAR TERM /TODAY/...

LIGHT PRECIP AND DRIZZLE RAPIDLY DECREASING IN COVERAGE TO THE
SOUTHEAST OF THE INDY METRO EARLY THIS MORNING...AND EXPECT IT TO BE
CLEAR OF THE FORECAST AREA BY 09-10Z. BACK EDGE OF LOWER CLOUDS ALSO
RAPIDLY DROPPING SOUTH AS DRIER AIR SPREADS INTO THE LOWER GREAT
LAKES. TEMPS WERE HOVERING NEAR FREEZING ACROSS FAR NORTHERN
SECTIONS OF THE FORECAST AREA WHERE SKIES HAD ALREADY CLEARED...WITH
MID AND UPPER 30S ELSEWHERE AT 08Z.

PRIMARY CHALLENGES FOR TODAY FOCUS OVER THE NEXT SIX HOURS THROUGH
MID MORNING WITH RESPECT TO LOW CLOUD COVERAGE AND THE POSSIBILITY
OF FOG DEVELOPMENT AS SKIES CLEAR. MOS AND LAMP GUIDANCE NOT
CAPTURING THE RAPIDITY OF THE CLEARING VERY WELL AND EVEN THE MOST
RECENT RUC DATA SEEMS TO BE FALLING BEHIND A BIT WITH RESPECT TO THE
SOUTHWARD SURGE IN CLEARING SINCE MIDNIGHT. ALREADY AT 08Z CLEARING
LINE IS APPROACHING THE NORTHERN INDY SUBURBS. HOWEVER...BACK EDGE
OF THE STRATOCU NOT PROGRESSING SOUTH AS QUICKLY OVER FAR EASTERN
INDIANA AND WESTERN OHIO. WITH LIGHT NORTHEAST FLOW THROUGH THE
LOWER LEVELS...QUITE PLAUSIBLE THAT THIS MAY SLOW THE DEPARTURE OF
THE STRATOCU ALONG THE I-70 CORRIDOR UNTIL CLOSER TO DAYBREAK. FOR
NOW...WILL MAINTAIN CLOUDS SOUTH OF I-70 THROUGH DAYBREAK WITH CLEAR
SKIES TO THE NORTH. POTENTIAL FOR FOG DEVELOPMENT IS GREATER OVER
NORTHERN COUNTIES WITH THE CLEARING. POSSIBILITY DOES EXIST FOR
THICKER FOG TO IMPACT A FEW LOCATIONS OVER FAR NORTHERN COUNTIES BUT
OVERALL LIGHT NORTHERLY FLOW AND CONTINUED EXPANSION OF DRIER
AIRMASS FROM THE NORTH SHOULD KEEP THICKER FOG CONFINED TO LOCALIZED
AREAS. WILL CARRY PATCHY FOG NORTH OF I-70 INTO MID MORNING AND
ADJUST ACCORDINGLY AS NEEDED. CONTINUING A MENTION OF PATCHY
FREEZING FOG OVER FAR NORTHERN COUNTIES WHERE SURFACE TEMPS LIKELY
TO BOTTOM OUT AT 28-30 DEGREES.

REMAINDER OF THE DAY WILL BE QUIET AS SKIES BECOME SUNNY UNDER
STRONG HIGH PRESSURE RIDGE. MODEL SOUNDINGS SHOW DEEP SUBSIDENCE
TAKING HOLD WITH CLEAR SKIES AND LIGHT NORTHERLY FLOW EXPECTED FOR
THE REST OF THE DAY.

TEMPS...MOS GUIDANCE SUPPORTED BY LOW LEVEL THERMALS AS TEMPS SHOULD
WARM INTO THE MID AND UPPER 40S THIS AFTERNOON.

&&

.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...

FORECAST CHALLENGES FOCUS ON PRECIP CHANCES TUESDAY NIGHT AS AN
UPPER LEVEL DISTURBANCE MOVES INTO THE REGION.

MUCH OF THE SHORT TERM WILL REMAIN TRANQUIL AS BROAD HIGH PRESSURE
RIDGE DOMINATES THE WEATHER PATTERN OVER THE OHIO VALLEY. MODEL
SOUNDINGS MAINTAIN DEEP SUBSIDENCE OVER CENTRAL INDIANA THROUGH
MONDAY NIGHT WHICH SHOULD KEEP SKIES LARGELY CLOUD-FREE. REMNANT
UPPER LEVEL FEATURE FROM SYSTEM THIS WEEKEND WILL PASS TO THE SOUTH
OF THE REGION WITH LITTLE FANFARE AS A RESULT. WEAK FRONTAL BOUNDARY
DROPS THROUGH THE FORECAST AREA LATE MONDAY NIGHT INTO TUESDAY BUT
WILL ONLY BRING A SUBTLE INCREASE IN HIGHER CLOUDS AS NO APPRECIABLE
MOISTURE IS PRESENT.

MODELS CONVERGING ON THE ARRIVAL OF ISENTROPIC LIFT AND MOISTURE
AHEAD OF A MID LEVEL SHORT WAVE TUESDAY NIGHT. WHILE TIMING OF THE
SHORT WAVE VARIES BETWEEN THE MODELS...INTRODUCTION OF LOW CHANCE
POPS FOR TUESDAY NIGHT APPEARS WARRANTED. ANALYSIS OF LOW LEVEL
THERMALS SUPPORT POTENTIAL OF A RA/SN MIX CHANGING PREDOMINANTLY
OVER TO LIGHT SNOW AS THE NIGHT PROGRESSES. AT THIS POINT...PRECIP
AMOUNTS LOOK LIMITED AT ONLY A COUPLE HUNDREDTHS WITH SNOW ACCUMS OF
A FEW TENTHS OF AN INCH AT BEST OVER NORTHERN COUNTIES.

TEMPS...LOW LEVEL THERMAL PROFILES SUPPORTED MOS GUIDANCE THROUGH
MUCH OF THE PERIOD. TEMPS ON MONDAY SHOULD BE A FEW DEGREES WARMER
THAN TODAY WITH ABUNDANT SUNSHINE AND SOUTHWEST FLOW DEVELOPING.
PASSAGE OF THE WEAK FRONT EARLY TUESDAY WILL SERVE TO KNOCK HIGHS
DOWN A FEW DEGREES TUESDAY...WITH COLDER AIR ARRIVING TUESDAY NIGHT.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...

THE MAIN FORECAST CHALLENGES FOR THE PERIOD ARE PRECIPITATION
CHANCES AND TEMPERATURES LATE IN THE PERIOD AS A DECENT PUSH OF
COLDER AIR SLIDES DOWN FROM CANADA.

THE MODELS ARE BEGINNING TO COME INTO AGREEMENT WITH THE TIMING OF
AN UPPER LEVEL WAVE PASSING THROUGH THE FORECAST AREA ON WEDNESDAY
WITH THE ECMWF JUST SLIGHTLY FASTER THAN THE GFS AND CANADIAN.
SUFFICIENT MOISTURE STILL LOOKS TO BE THE LIMITING FACTOR SO
STICKING WITH CHANCE POPS PROVIDED BY ALLBLEND SEEMS LIKE THE BEST
MOVE FOR NOW. ALSO INTRODUCED A SLIGHT CHANCE ACROSS THE EAST FOR
WEDNESDAY NIGHT TO ACCOUNT FOR THE SLIGHTLY SLOWER MODEL SOLUTIONS.
WITH TEMPERATURES CONTINUING TO BE AROUND NORMAL VALUES...LOWS IN
THE MID 20S AND HIGHS IN THE MID 30S...CONTINUED WITH A RAIN/SNOW
MIX IN THE GRIDS.

SURFACE HIGH PRESSURE WILL SLIDE ACROSS THE REGION ON THURSDAY. THIS
WILL CAUSE SOUTHWESTERLY WINDS TO RETURN ALLOWING TEMPERATURES TO
RISE TO ABOVE NORMAL VALUES ONCE AGAIN. HOWEVER...THE WARM UP WILL
BE SHORT LIVED AS A STRONG UPPER LOW NEAR HUDSON BAY TRANSPORTS A
MUCH COLDER AIRMASS TOWARDS CENTRAL INDIANA. DECREASED ALLBLEND
TEMPERATURES 2-3 DEGREES HEADING INTO THE WEEKEND WITH THE GFS
DEPICTING 850 MB TEMPERATURES APPROACHING -20 C.

&&

.AVIATION /DISCUSSION FOR THE 05/09Z TAF UPDATE/...

UPDATE...
THE NEXT FEW HOURS CONTINUE TO BE THE CRITICAL TIME FRAME FOR FOG
DEVELOPMENT AT KIND. CLEARING HAS ALREADY TAKEN PLACE AT
KLAF...AND THE LINE IS CURRENTLY JUST TO THE NORTH OF KIND.
HOWEVER...VISIBILITIES HAVE NOT DROPPED DRASTICALLY AT KLAF OVER
THE LAST FEW HOURS WITH CLEAR SKIES...SO WILL BASE KIND ON THAT
TREND FOR NOW. SO...ALL INDICATIONS AT THIS TIME ARE LEADING TO
MVFR CONDITIONS THROUGH DAYBREAK...AND CONTINUED IMPROVEMENT
AFTER THAT.


PREVIOUS DISCUSSION...
RESTRICTIONS LIKELY IN SOME FORM THROUGH THE MORNING
HOURS...IMPROVING TO VFR THEREAFTER.

QUESTION IS WHERE CLEARING WILL OCCUR AND FOG WILL DEVELOP. LAF MOST
LIKELY TO SEE CLEARING...BUT IND CANNOT BE RULED OUT. 10-12Z WILL BE
THE MOST CRITICAL TIME FRAME AT IND. IF MOISTURE SCOURS OUT ENOUGH
TO CLEAR...DENSE FOG COULD BE POSSIBLE. AS IT LOOKS NOW...EXPECTING
IFR LOW CLOUD TO CONTINUE THROUGH THE MORNING WITH MAINLY MVFR
VISIBILITIES.

WINDS WILL GO FROM EAST/NORTHEASTERLY TO MORE NORTHERLY
OVERNIGHT...BUT SPEEDS SHOULD GENERALLY REMAIN LESS THAN 10KT.


&&


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

&&

$$

SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....HOMANN/RYAN
AVIATION...NIELD/TDUD



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