Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 220833
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
433 AM EDT TUE APR 22 2014

.UPDATE...

THE AVIATION SECTION HAS BEEN UPDATED BELOW.

&&

.SYNOPSIS...
ISSUED AT 401 AM EDT TUE APR 22 2014

A COLD FRONT WILL BE CLEARING THE AREA AROUND THE START OF THE
FORECAST PERIOD...WITH HIGH PRESSURE BUILDING IN QUICKLY BEHIND
IT. THE HIGH WILL KEEP THINGS DRY THROUGH AT LEAST EARLY
THURSDAY INTO THURSDAY NIGHT...WHEN AN ELONGATED AREA OF LOW PRESSURE
AND ASSOCIATED COLD FRONT WILL MOVE THROUGH THE AREA...BRINGING
SHOWERS AND SOME THUNDERSTORMS TO THE AREA. SOME FROST APPEARS
POSSIBLE TOMORROW NIGHT...BUT TEMPERATURES WILL BE BORDERLINE
ACROSS MUCH OF THE AREA. MODELS SUGGEST A CHANGE BACK TO A COOLER
AND DAMP PATTERN LATER IN THE PERIOD AS A LOW PRESSURE SYSTEM
DROPS INTO THE CENTRAL PORTION OF THE COUNTRY AND BEGINS T0 CUT
OFF.

&&

.NEAR TERM /TODAY/...
ISSUED AT 401 AM EDT TUE APR 22 2014

EXPECT FRONT TO BE ON ITS WAY OUT OF THE AREA AT 12Z...AND PRECIP
HAS BEEN ISOLATED AND VERY LIGHT AT BEST FOR SEVERAL HOURS...SO
CONFIDENT THAT NO POPS WILL BE NECESSARY TODAY. CLEARING LINE IS
ADVANCING STEADILY...AND EXPECT MOST OF THE AREA TO BE CLEAR OR
MOSTLY CLEAR BY MID TO LATE MORNING.

MODEL SOUNDINGS SUGGEST FAIRLY GOOD MIXING TODAY AND SOME WIND
GUSTS UP TO 30 MPH...AND HAVE INCLUDED THIS IN THE GRIDS. GUSTS
WILL DIE DOWN IN TYPICAL DIURNAL FASHION THIS EVENING.

CONSENSUS NUMBERS APPEARED TOO COOL BASED ON UPSTREAM NUMBERS AND
LOW LEVEL THICKNESSES...SO BUMPED UP CLOSER TO A MOS BLEND.

&&

.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
ISSUED AT 401 AM EDT TUE APR 22 2014

MAJORITY OF THE SHORT TERM LOOKS DRY AS HIGH PRESSURE CONTROLS THE
AREA. SOME GUIDANCE WANTS TO DEVELOP SOME PRECIP ACROSS THE
NORTH/NORTHWEST WEDNESDAY NIGHT ASSOCIATED WITH AN AREA OF
MIDLEVEL FRONTOGENESIS...BUT LOW LEVELS REMAIN DRY PER FORECAST
SOUNDINGS AND CONTINUED SURFACE RIDGE PRESENCE. WILL CARRY NO POPS
UNTIL THURSDAY AFTERNOON WHEN THE FRONTAL BOUNDARY APPROACHES.
HIGH END LIKELIES APPEAR WARRANTED WITH THE FRONT AS IS PASSES
THURSDAY EVENING...TAPERING QUICKLY AS THE FRONT PASSES LATE IN
THE OVERNIGHT. K INDEX AND DEEP LAYER SHEAR PROGS SUGGEST
POTENTIAL FOR ORGANIZED CONVECTION...BUT NEAR SURFACE INSTABILITY
IS MINIMAL AND INSTABILITY PROFILES ARE VERY NARROW. SPC DAY 3 SEE
TEXT/5 PERCENT SEVERE PROBS ARE REASONABLE.

MODEL CONSENSUS TEMPS APPEARED A BIT TOO COOL ACROSS THE BOARD ON
HIGHS...SO MOST PERIODS LEANED TOWARD THE WARMER MOS BLEND. MAY
END UP NEEDING FROST ADVISORY HEADLINES FOR PORTIONS OF THE AREA
TOMORROW NIGHT...BUT TEMPERATURES LOOK BORDERLINE AT THE MOMENT
AND WINDS STAY UP A BIT. WILL CARRY SOME FROST IN THE GRIDS BUT
HOLD OFF ON ANY HEADLINES FOR THE TIME BEING.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
ISSUED AT 312 AM EDT TUE APR 22 2014

EXTENDED MODEL GUIDANCE COMING INTO BETTER AGREEMENT ON AN UPPER
LEVEL PATTERN CHANGE TAKING PLACE DURING THE EXTENDED...FROM A
PROGRESSIVE ZONAL FLOW TO A MUCH MORE BLOCKY PATTERN ALOFT BY
EARLY NEXT WEEK. THIS WILL RESULT IN A SHIFT TO MORE UNSETTLED AND
LIKELY COOLER WEATHER OVER THE OHIO VALLEY FOR NEXT WEEK.

OCCLUDED LOW PRESSURE WILL BE LOCATED OVER THE GREAT LAKES FRIDAY
MORNING WITH RAIN AND THUNDERSTORMS WITH THE ASSOCIATED BOUNDARY
WELL EAST OF THE FORECAST AREA. ZONAL FLOW IN THE WAKE OF THE
OCCLUDED FRONT AND A RESUMPTION OF LOW LEVEL WARM ADVECTION AND
SOUTHWEST FLOW WILL MAKE FRIDAY THE WARMEST DAY OF THE EXTENDED
WITH TEMPS MAINLY IN THE LOWER/MIDDLE 70S. A TRAILING UPPER WAVE
AND SURFACE LOW WILL PINWHEEL BEHIND THE OCCLUDED LOW FRIDAY NIGHT
AND DROP A SECONDARY FRONT INTO THE REGION. HARD TO JUSTIFY MORE
THAN LOW CHANCE POPS FOCUSED OVER THE NORTHERN COUNTIES FRIDAY
NIGHT WITH MOISTURE LACKING ALONG THE FRONT AND BULK OF THE
FORCING ALOFT REMAINING TO OUR NORTH OVER THE GREAT LAKES.

THE MORE SUBSTANTIAL CHANGE FROM THE PASSAGE OF THE FRONT WILL BE
A SHIFT BACK TO COOLER TEMPERATURES AS CANADIAN HIGH PRESSURE
POKES DOWN INTO THE REGION FOR SATURDAY. AFTER DRY WEATHER
SATURDAY...INCREASINGLY UNSETTLED CONDITIONS DEVELOPING FOR THE
SECOND HALF OF THE WEEKEND AND POTENTIALLY INTO THE FIRST HALF OF
NEXT WEEK. HIGHLY AMPLIFIED BLOCKY FLOW ALOFT DEVELOPING WITH A
SHARPENING UPPER WAVE OVER THE ROCKIES. AS THE UPPER LOW DEEPENS
AND SHIFTS INTO THE HIGH PLAINS...A STRONG SURFACE LOW WILL EJECT
OUT INTO THE PLAINS WITH A WARM FRONT EXTENDING EAST INTO THE OHIO
VALLEY. STILL SOME DIFFERENCES REGARDING WHERE THE WARM FRONT SETS
UP AND THE EVENTUAL TRACK OF THE SURFACE LOW...BUT PRESENCE OF
STRONG HIGH PRESSURE OVER JAMES BAY SUGGESTIVE OF A MORE
SUPPRESSED SOLUTION WITH CENTRAL INDIANA LIKELY REMAINING NORTH OF
THE WARM FRONT. WILL MAINTAIN POPS FROM SATURDAY NIGHT THROUGH THE
END OF THE PERIOD. LEANED TOWARDS COOLER ALLBLEND WITH HIGHS
LARGELY REMAINING IN THE 50S AND LOWER 60S SUNDAY AND MONDAY.

EXTENDED GUIDANCE FAVORING THE UPPER LOW OVER THE PLAINS BECOMING
CUTOFF FROM THE MEAN FLOW AS IT MEANDERS EAST INTO THE OHIO AND
TENNESSEE VALLEYS NEXT WEEK. STRONGLY SUGGESTIVE OF A CLOUDY COOL
DAMP PATTERN TO FINISH OUT THE MONTH.

&&

.AVIATION /DISCUSSION FOR THE 220900Z TAF UPDATE/...
ISSUED AT 433 AM EDT TUE APR 22 2014

ALL OF THE PRECIP HAS SHIFTED EAST OF THE TERMINALS AS THE COLD
FRONT IS ABOUT TO PASS KHUF AND KIND. WINDS WILL GRADUALLY VEER TO
NORTHWEST AND INCREASE TO 10-15KTS BY DAYBREAK AS THE FRONT PASSES.
POCKETS OF MVFR VISIBILITIES AND STRATUS BEHIND THE BOUNDARY WILL
IMPACT ALL OF THE TERMINALS OVER THE NEXT 2-4 HOURS. CLEARING SKIES
WILL THEN FOLLOW AS THE HIGH BUILDS IN.

06Z DISCUSSION FOLLOWS.

MOSTLY VFR...HOWEVER FIRST TO START OFF THE PERIOD A PERIOD OF MVFR
CEILINGS POSSIBLE THROUGH EARLY THIS MORNING WITH SCATTERED SHOWER
ACTIVITY. MODERATE TO BRISK WINDS WILL OCCUR TODAY...FIRST ALONG THE
FRONT AND THEN POST FRONTAL PASSAGE.

WILL CONTINUE TO OMIT MENTION OF THUNDER AS THERE CURRENTLY IS VERY
LITTLE CONVECTION ON THE RADAR. FOLLOWING THE COLD FRONT MUCH DRIER
AIR WILL SPREAD IN FROM THE NORTHWEST CAUSING RAPID CLEARING BY MID
OR LATE MORNING. WINDS WILL BE BECOMING NORTHWEST AND INCREASING UP
TO 15 KNOTS AND GUSTS TO 25 KNOTS BY 15Z THIS MORNING.

&&

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

&&

$$

SYNOPSIS...NIELD
NEAR TERM...NIELD
SHORT TERM...NIELD
LONG TERM...RYAN
AVIATION...SMF/RYAN

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