Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 210433
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
1233 AM EDT TUE APR 21 2015

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

&&

.SYNOPSIS...
ISSUED AT 357 PM EDT MON APR 20 2015

A LARGE UPPER LOW WILL CONTINUE TO CONTROL THE WEATHER OVER CENTRAL
INDIANA THROUGH MOST OF THE PERIOD. WINDY CONDITIONS WILL BE PLACE
TUESDAY AS A SURFACE LOW MOVES AWAY FROM THE AREA. TEMPERATURES WILL
DROP BELOW NORMAL AND STAY THERE UNDER NORTHWEST FLOW AND MAINLY DRY
CONDITIONS WILL ENSUE AS WELL WITH THE EXCEPTION OF GOOD RAIN
CHANCES FRIDAY NIGHT AND SATURDAY.

&&

.NEAR TERM /TONIGHT/...
ISSUED AT 1000 PM EDT MON APR 20 2015

HELD ON TO SLIGHT CHANCE OF SHOWERS A LITTLE LONGER PER RADAR AND
HRRR TRENDS. REMAINDER OF FORECAST IN GOOD SHAPE. PREVIOUS
DISCUSSION FOLLOWS.

ISSUED AT 357 PM EDT MON APR 20 2015

SCATTERED LIGHT SHOWERS THIS AFTERNOON WILL GIVE WAY TO A SLIGHT
CHANCE FOR SHOWERS IN THE NORTH TONIGHT AS A WEAK UPPER WAVE MOVES
THROUGH NORTHERN INDIANA THROUGH THE MAIN UPPER LOW. AFTER THAT WILL
SLOWLY SEE CLOUD COVER DECREASE DURING THE NIGHT. WINDS GUSTS WILL
DROP OFF BUT WINDS SHOULD STAY UP DURING THE NIGHT SO DON/T EXPECT
TEMPERATURES TO DROP BEYOND THE LOW 40S WHICH WAS WARMER THAN MOS
GUIDANCE NUMBERS.

&&

.SHORT TERM /TUESDAY THROUGH THURSDAY/...
ISSUED AT 357 PM EDT MON APR 20 2015

MAIN FORECAST FOCUS IS ON WINDS TUESDAY AND THEN TEMPERATURES.
MODELS ARE IN DECENT AGREEMENT SO WILL GENERALLY USE AN AVERAGE.

THE PRESSURE GRADIENT ACROSS THE AREA ON TUESDAY LOOKS SIMILAR TO
TODAY TO START BUT COULD WEAKEN A BIT DURING THE DAY. A LOW LEVEL
JET WILL PASS THROUGH THE NORTH DURING THIS TIME BRINGING WITH
SPEEDS OF 40-50 KTS IN BOTH THE NAM AND GFS. FORECAST SOUNDINGS
INDICATE A VERY DEEP MIXED LAYER WITH WESTERLY WINDS THROUGH THE
LAYER. THIS SHOWS POTENTIAL TO MIX DOWN 40+ KT WINDS FROM 5000+ FT.
THUS HAVE ISSUED A WIND ADVISORY FROM LATE MORNING THROUGH THE DAY.
WIND GUSTS SHOULD LESSEN BEFORE SUNSET.

A WEAK UPPER WAVE WILL MOVE THROUGH THE AREA ON TUESDAY NIGHT. THERE
WILL BE LITTLE MOISTURE TO WORK WITH BUT COULD SEE THIS PRODUCE VERY
LIGHT RAIN IN A FEW SPOTS SO INCLUDED LOW POPS. THINK MET NUMBERS
ARE SIGNIFICANTLY OVERDONE CONSIDERING THE AVAILABLE MOISTURE...AND
EVEN CUT FROM THOSE OF THE DRIER MAV. WITH THE EXTRA CLOUD COVER
THOUGH LEANED WARMER THAN GUIDANCE LOWS.

HIGH PRESSURE BUILDS IN FOR WEDNESDAY THROUGH THURSDAY. WENT WITH
CONSENSUS HIGHS/LOWS DURING THAT TIME. MAY HAVE TO CONSIDER
INCLUDING FROST FOR WEDNESDAY NIGHT/THURSDAY MORNING WITH LATER
ISSUANCE BUT RIGHT NOW TOO MUCH UNCERTAINTY ON WINDS DROPPING OFF
QUICKLY ENOUGH.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
ISSUED AT 222 PM EDT MON APR 20 2015

COOL AND MAINLY DRY PATTERN LOOKS TO REMAIN IN PLACE FOR THE FIRST
PART OF THIS PERIOD...AS A BROAD TROUGH REMAINS IN PLACE OVER THE
EASTERN HALF OF THE UNITED STATES. BY SATURDAY NIGHT THE TROUGH
BEGINS TO DEPART TO THE EAST AND THE ECMWF AND GFS DEPICT A WEAK
UPPER DISTURBANCE PUSHING THROUGH THE TENNESSEE VALLEY. LIMITED
MOISTURE LOOKS TO BE IN PLACE AHEAD OF THIS SYSTEM AS GULF
MOISTURE REMAINS CUT OFF AND BEST FORCING REMAINS SOUTH OF THE
FORECAST AREA. FOR NOW...HAVE INCLUDED LOW CHANCE POPS AS THIS
SYSTEM PASSES.

RIDGING AND THEN BUILDS ALOFT ON SUNDAY AND MONDAY...ENDING ANY
RAIN THREAT...HOWEVER NORTHEASTERLY SURFACE FLOW WILL CONTINUE TO
KEEP TEMPERATURES COOL.

&&

.AVIATION /DISCUSSION FOR THE 210600Z TAF ISSUANCE/...

ISSUED AT 1231 AM EDT TUE APR 21 2015

GOOD CONFIDENCE VFR CONDITIONS WILL PERSIST THROUGH AT LEAST 06Z
WEDNESDAY PER MODEL SOUNDINGS AND RH TIME SECTIONS. SHOULD SEE
MOSTLY CLEAR SKIES OVERNIGHT AND INCREASING AFTERNOON MID DECK
BEFORE CU ROLLS IN THIS EVENING AND OVERNIGHT AHEAD OF AN UPPER WAVE
AROUND THE BASE OF THE ONTARIO UPPER LOW.

WINDS WILL BE THE MAIN ISSUE AS SURFACE PRESSURE GRADIENT REMAINS
TIGHT IN BETWEEN THE AREA OF LOW PRESSURE OVER THE GREAT LAKES AND
HIGH PRESSURE OVER THE SOUTH.

WEST WINDS 10 TO 15 KNOTS BUT INCREASE AGAIN AFTER 14Z WITH
SUSTAINED WINDS TO 25 KNOTS AND GUSTS TO NEAR 40 KNOTS BY AFTERNOON
AT LAF AND IND. HUF AND BMG SHOULD NOT BE QUITE AS GUSTY BUT SHOULD
STILL SEE GUSTS OVER 30 KNOTS TOMORROW AFTERNOON. WINDS WILL THEN
ONCE AGAIN DROP OFF A BIT AFTER SUNSET.

&&

.IND WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 11 AM THIS MORNING TO 8 PM EDT THIS EVENING
FOR INZ021-028>031-035>049.

&&

$$

SYNOPSIS...CP
NEAR TERM...CP/NIELD
SHORT TERM...CP
LONG TERM...PUMA
AVIATION...KOCH

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