Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 130652
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
252 AM EDT SUN APR 13 2014

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

&&

.SYNOPSIS...
ISSUED AT 301 PM EDT SAT APR 12 2014

WARM SPRING WEATHER WILL CONTINUE INTO SUNDAY AS THE REGION REMAINS
UNDER THE INFLUENCE OF A HIGH PRESSURE RIDGE. A STRONG COLD FRONT
WILL TRACK ACROSS THE OHIO VALLEY SUNDAY NIGHT THROUGH EARLY
TUESDAY...BRINGING RAIN AND EMBEDDED THUNDERSTORMS ALONG WITH A
RETURN TO MUCH COOLER WEATHER. CHILLY TEMPS WILL PERSIST THROUGH
MIDWEEK...WITH TEMPS RECOVERING TO SEASONABLE LEVELS BY FRIDAY AND
SATURDAY. PRECIP CHANCES WILL RETURN BY THE END OF THE WEEK AS
WELL.

&&

.NEAR TERM /REST OF TONIGHT/...
ISSUED AT 935 PM EDT SAT APR 12 2014

CURRENT FORECAST IS ON TRACK...ONLY MINOR CHANGES IN GRIDS MAINLY TO
BACK OFF ON SKY COVER A LITTLE AS THICKER HIGH CLOUDS SHOULD REMAIN
TO OUR NORTH OVERNIGHT.  PORTION OF PREVIOUS NEAR TERM DISCUSSION
FOLLOWS...

HIGH PRESSURE RIDGE TO OUR EAST WILL KEEP DRY CONDITIONS ACROSS
CENTRAL INDIANA TONIGHT. HOWEVER...EXPECT AN INCREASE IN MID AND
HIGH CLOUDS OVERNIGHT COURTESY OF THE CONVECTION TO THE NORTHWEST.
COULD SEE SOME STRATOCU TONIGHT AS WELL WITH CONTINUED WARM
ADVECTION. EXPECT GUSTS TO DROP OFF NEAR OR SHORTLY AFTER SUNSET AS
THE MIXING LAYER BREAKS DOWN AND THE NOCTURNAL INVERSION
ESTABLISHES. PRESENCE OF TIGHT SURFACE PRESSURE GRADIENT AHEAD OF
THE FRONTAL BOUNDARY THOUGH SHOULD ENSURE SOUTHWEST WINDS HOLDING UP
AT 10-15MPH ALL NIGHT.

TEMPS...WITH WARM ADVECTION...NO DECOUPLING TO SURFACE WINDS AND
POTENTIAL FOR MORE CLOUD COVER TONIGHT...EXPECT LOWS TO REMAIN A
COUPLE DEGREES EITHER SIDE OF 60. MOS GUIDANCE SUPPORTS THIS
THINKING WELL.

&&

.SHORT TERM /SUNDAY THROUGH TUESDAY/...
ISSUED AT 301 PM EDT SAT APR 12 2014

FORECAST CHALLENGES FOCUS ON PRECIP CHANCES LATE SUNDAY INTO EARLY
TUESDAY...AND TEMPS MONDAY AND TUESDAY AS WINTER MAKES A
REAPPEARANCE.

SURFACE RIDGE WILL REMAIN ANCHORED OVER THE SOUTHEAST STATES SUNDAY
WITH SOUTHWEST FLOW ALOFT. AN UPPER WAVE WILL TRACK OUT OF THE
SOUTHERN ROCKIES AND INTO THE SOUTHERN PLAINS. AS IT DOES...IT WILL
PROMPT A SECONDARY STRONGER LOW PRESSURE TO DEVELOP ALONG THE FRONT
AND TRACK INTO THE MID MISSISSIPPI VALLEY BY SUNDAY NIGHT. THE UPPER
WAVE WILL FINALLY FORCE THE RIDGING TO BEGIN TO BREAK DOWN AND SHIFT
EAST INTO THE ATLANTIC...WITH THE COLD FRONT MOVING INTO THE REGION
EARLY MONDAY.

WHILE STILL UNDER THE INFLUENCE OF THE RIDGE SUNDAY...EXPECT ANOTHER
WARM WINDY DAY ACROSS CENTRAL INDIANA. POTENTIAL EXISTS FOR MORE
CLOUD COVER THAN TODAY AS LOW LEVEL MOISTURE ADVECTS INTO THE REGION
AND THE FRONT INCHES CLOSER FROM THE WEST. A LOW LEVEL JET WILL
PIVOT AROUND THE BASE OF THE LOW PRESSURE MOVING ALONG THE FRONT AND
INTO THE REGION DURING THE AFTERNOON. WITH THE BOUNDARY LAYER WELL
MIXED ONCE AGAIN...POTENTIAL EXISTS FOR WIND GUSTS OF 35-40MPH. CUT
BACK TO JUST LOW POPS OVER THE NORTHERN WABASH VALLEY AFTER 21Z AS
DEEPER FORCING ASSOCIATED WITH THE FRONT REMAINS WEST OF THE REGION.

THE STRONGER ISENTROPIC LIFT AND DEEPER MOISTURE WILL FINALLY
OVERSPREAD THE FORECAST AREA SUNDAY NIGHT WITH WIDESPREAD RAIN
DEVELOPING. INSTABILITY IS PRESENT BUT UNDERWHELMING TO SAY THE
LEAST. EXPECT EMBEDDED THUNDERSTORMS AT BEST AS THE INSTABILITY AXIS
SHIFTS EAST AHEAD OF THE FRONT EARLY MONDAY. FRONTAL PASSAGE TIMING
IS RELATIVELY CLOSE AMONGST THE VARIOUS MODEL GUIDANCE...PASSING
FROM NORTHWEST TO SOUTHEAST BETWEEN 12-18Z MONDAY. HEAVIEST RAINFALL
LIKELY TO ACCOMPANY THE BOUNDARY AND IMPACT THE FORECAST AREA
THROUGH EARLY AFTERNOON.

WHILE PRECIP COVERAGE IS LIKELY TO DIMINISH WITH RAINFALL RATES
LIGHTENING FOR A PERIOD OF TIME DURING THE AFTERNOON...MODEL
CONSENSUS FAVORING YET ANOTHER WAVE DEVELOPING ALONG THE FRONT OVER
THE TENNESSEE VALLEY AND TRACKING INTO OHIO MONDAY NIGHT. THE LOW
WILL STRENGTHEN AS AN INCREASINGLY AMPLIFIED UPPER WAVE DIVES ACROSS
THE PLAINS. THIS WILL SERVE TO SPREAD ANOTHER ROUND OF PRECIP INTO
THE FORECAST AREA FROM LATE MONDAY AFTERNOON INTO MONDAY NIGHT. AS
THAT TAKES PLACE...PROGRESSIVELY COLDER LOW LEVEL AIR WILL ADVECT
INTO THE REGION BEHIND THE FRONT MONDAY NIGHT. STILL APPEARS THAT
COLDER AIR WILL ARRIVE BEFORE PRECIP DEPARTS...ALLOWING FOR A FEW
HOURS WHERE RAIN COULD MIX WITH OR POSSIBLY CHANGEOVER COMPLETELY TO
SNOW BEFORE ENDING. NO ACCUMULATION EXPECTED CONSIDERING GROUND
TEMPERATURES AND THAT PRECIPITATION SHOULD BE VERY LIGHT.

ANY LINGERING PRECIP WILL END TUESDAY MORNING AS HIGH PRESSURE
BUILDS IN WITH DRY CHILLY AIR FOR THE REMAINDER OF THE DAY. EXPECT A
FAIRLY HEALTHY CU FIELD TO ESTABLISH WITH CONVECTIVE TEMPS IN THE
30S AND REGION RESIDING UNDER THE COLD POOL. GUSTY NORTHWEST WINDS
WILL MAKE FOR A RAW DAY ALL IN ALL. CONSIDER THIS A PARTING SHOT
FROM OLD MAN WINTER.

TEMPS...HAVE CONSISTENTLY WARMED A FEW DEGREES ABOVE GUIDANCE THE
LAST FEW DAYS AND SEE NO REASON SUNDAY WOULD BE ANY DIFFERENT...EVEN
WITH MORE CLOUD COVER. A FEW LOCATIONS IN OUR SOUTHEAST COUNTIES
COULD MAKE IT TO 80 SUNDAY AFTERNOON. MONDAY HIGHS WILL BE TRICKY
WITH TIMING OF THE FRONTAL PASSAGE BEING KEY. HAVE LEANED CLOSER TO
THE WARMER METMOS AS EXPECT TEMPS TO REBOUND A FEW DEGREES IN THE
MORNING BEFORE FALLING ONCE THE FRONT PASSES. UNDERCUT GUIDANCE
TUESDAY AS TEMPS ARE LIKELY TO STRUGGLE OUT OF THE LOW/MID 40S. FOR
LOWS...NEAR WARMER METMOS SUNDAY/MONDAY NIGHTS.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
ISSUED AT 252 AM EDT SUN APR 13 2014

MAIN FOCUS TO THE EXTENDED WILL BE ON TIMING OF POPS LATE NEXT WEEK
AND EARLY NEXT WEEKEND.

MODELS ARE NOT COMING ANYWHERE NEAR A CONSENSUS WITH THE STRENGTH
AND TIMING OF A LATE WEEK AND EARLY WEEKEND LOW PRESSURE SYSTEM WITH
THE 00Z GFS BEING BY FAR THE STRONGEST...LIFTING A SURFACE LOW
PRESSURE SYSTEM NORTHEAST ACROSS ILLINOIS AND INTO THE GREAT LAKES
ON FRIDAY. HOWEVER...ALL THE MODELS ARE REASONABLY CLOSE IN
SUGGESTING BY THEIR QPF FIELDS THAT RAIN SHOWERS WILL MOVE IN FROM
THE WEST BY EARLY FRIDAY...AND DEPART EAST FRIDAY NIGHT. SO...WILL
ACCEPT REGIONAL CHANCE POPS FOR THAT PERIOD THAT REFLECT THE ABOVE
THINKING. THE REST OF THE FORECAST LOOKS DRY AS HIGH PRESSURE BUILDS
IN FROM THE SOUTHWEST. INSTABILITY PROGS ARE NOT STRONGLY SUGGESTING
THUNDER...SO WILL LEAVE IT OUT FOR NOW.

LOW LEVEL THERMAL PROGS AND EXPECTED CLOUD COVER AND WEATHER SUGGEST
NOT DEVIATING MUCH FROM REGIONAL BLEND REGARDING TEMPERATURES WITH
TEMPERATURES RETURNING TO NEAR NORMAL BY THURSDAY AFTER A COOL START
WEDNESDAY.

&&

.AVIATION /DISCUSSION FOR THE 130600Z TAFS/...
ISSUED AT 1221 AM EDT SUN APR 13 2014

THIS EVENING/S UPPER AIR INDICATES 25-30KT WINDS AROUND 020. SHORT
TERM MODEL DATA SUGGEST THE LOW LEVEL JET WILL INCREASE DURING THE
NEXT FEW HOURS...WITH THE POTENTIAL FOR WINDS WITHIN THE JET OF
45-50KT...SUGGESTING THE POTENTIAL FOR LOW LEVEL WIND SHEAR. SURFACE
WINDS HAVE DROPPED OFF FOR NOW...BUT SHOULD PICK UP AGAIN LATER AS
THE LOW LEVEL JET STRENGTHENS. AT THIS TIME...APPEARS BOUNDARY LAYER
WILL REMAIN MIXED UP ENOUGH TO PREVENT MUCH OF A NOCTURNAL INVERSION
FROM DEVELOPING...SO ANY WIND SHEAR SHOULD BE BELOW CRITERIA. WILL
KEEP AN EYE ON SURFACE WIND TRENDS OVERNIGHT.

OTHERWISE...EXPECTING SURFACE WINDS TO BEGIN GUSTING OVER 20 KTS
WITHIN A COUPLE OF HOURS AFTER SUNRISE...WITH POTENTIAL FOR GUSTS
30-32 KTS BY 131800Z. SURFACE WIND DIRECTIONS FROM 190-210 DEGREES.

SOME CLOUD COVER BASED AROUND 050 MAY DEVELOP TOWARDS MIDDAY ON
SUNDAY...WITH HIGHER CLOUDS ABOVE. FINALLY...SHOULD SEE CEILINGS
LOWER AND SHOWERS MOVE IN AFTER 02Z SUNDAY NIGHT. MODELS WERE ALSO
SHOWING PLENTY OF INSTABILITY TO MERRITT VCTS.

&&

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

&&

$$

SYNOPSIS...RYAN
NEAR TERM...RYAN/JH
SHORT TERM...RYAN
LONG TERM...MK
AVIATION...JAS/MK

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