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000
FXUS63 KIND 180820
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
420 AM EDT SAT MAY 18 2013

.UPDATE...

THE AVIATION SECTION HAS BEEN UPDATED BELOW.

&&

.SYNOPSIS...
ISSUED AT 143 AM EDT SAT MAY 18 2013

A WEAK AREA OF LOW PRESSURE WILL DRIFT INTO THE OHIO VALLEY AND
ACROSS SOUTHERN INDIANA. THIS WILL BRING CHANCES FOR SHOWERS AND
THUNDERSTORMS TODAY. A WEAK RIDGE OF HIGH PRESSURE WILL BUILD ACROSS
THE AREA ON SUNDAY. EARLY NEXT WEEK A LARGE TROUGH CARVES OUT OVER
THE WESTERN HALF OF THE COUNTRY INTO THE WEEKEND WHICH WILL BRING
WARMER AIR FOR MUCH OF NEXT WEEK ALONG WITH ANOTHER COUPLE DAYS OF
STORMY WEATHER MONDAY INTO MID WEEK.

&&

.NEAR TERM /TODAY/...
ISSUED AT 143 AM EDT SAT MAY 18 2013

MODELS DEPICT A WEAK UPPER LOW PUSHING THROUGH THE OHIO VALLEY AND
SOUTHERN INDIANA...THEN EXITING THE AREA BY LATE THIS AFTERNOON.
APPEARS WEAK FORCING ASSOCIATED WITH THE S/WV AND DAYTIME HEATING
WILL BE THE MAIN FORCING MECHANISMS FOR CONVECTIVE DEVELOPMENT.
GUIDANCE IS SHOWING CHANCES FOR THIS ACTIVITY ALL ACROSS THE
FORECAST AREA...WITH BEST CHANCES SOUTH OF I-70...BUT NOT LIMITED TO
THIS AREA. BUMPED UP POPS AND TRENDED TEMPS AT OR SLIGHTLY ABOVE MOS
DESPITE CLOUD COVER AND PRECIP CHANCES WE SHOULD EASILY BE ABLE TO
ACHIEVE TEMPS RANGING FROM UPPER 70S TO AROUND 80.

&&

.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
ISSUED AT 143 AM EDT SAT MAY 18 2013

DRIER AIR WILL QUICKLY BE INFILTRATING BACK INTO THE AREA BY THIS
EVENING...NOT BEFORE A FEW SHOWERS EXIT THE REGION TO THE EAST. WEAK
RIDGING BUILDS BACK OVER THE AREA TONIGHT AND SKIES WILL ATTEMPT TO
CLEAR OUT...BUT SOME MID TO HIGH LEVEL CLOUDS WILL REMAIN. POSSIBLY
SOME PATCHY FOG EARLY SUNDAY MORNING. WILL CONTINUE WITH A DRY
FORECAST STARTING LATE TONIGHT THROUGH EARLY MONDAY. 850 MB TEMPS
STILL LOOK QUITE WARM BY EARLY NEXT WEEK. LOOK FOR HIGH TEMPS IN THE
MID 80S BOTH SUNDAY AND MONDAY. MODELS ARE IN A BIT OF A
DISAGREEMENT WITH REGARD TO THE TIMING OF THE NEXT SYSTEM. FOR NOW
HAVE INTRODUCED SLIGHT CHANCE TO LOW CHANCE POPS STARTING MONDAY
AFTERNOON AND MONDAY NIGHT.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
ISSUED AT 229 AM EDT SAT MAY 18 2013

LONG TERM CONTINUES TO BE DOMINATED BY ONE MAIN SURFACE AND UPPER
LEVEL LOW MOVING EXTREMELY SLOWLY FROM THE NORTHERN PLAINS/UPPER
MIDWEST INTO THE OHIO VALLEY AND THE MIDATLANTIC STATES THROUGH
THE COMING WEEK. BROAD SOUTHWEST FLOW MOVING WARM MOIST AIR INTO
THE AREA WILL MERIT AT LEAST CHANCE POPS MOST ALL PERIODS THROUGH
THE LATE PORTION OF THE WEEK...WITH SOME LIKELIES LATE TUESDAY
INTO WEDNESDAY AS THE HEART OF THE SYSTEM APPROACHES THE AREA.
INITIALIZATION HANDLED THIS WELL AND ONLY A FEW MINOR TWEAKS WERE
REQUIRED.

TEMPS INITIALIZED WELL AND SHOULD BE GRADUALLY COOLING BACK DOWN
TO NEAR OR JUST SLIGHTLY BELOW NORMAL VALUES BY LATE IN THE WEEK
AS COOLER AIR MOVES INTO THE AREA ON THE BACK SIDE OF THE LOW.

&&

.AVIATION /DISCUSSION FOR THE 18/09Z TAF UPDATE/...
ISSUED AT 420 AM EDT SAT MAY 18 2013

FOG HAS BEEN SLOW TO DEVELOP SAVE FOR LAF WHERE CLEARING HAS
OCCURRED. LAF DOWN TO 1SM AND MAY GO LOWER...BUT WILL KEEP 1SM AS
THE LOWEST FOR NOW AND MONITOR. OTHERWISE...HAVE AMENDED IND/HUF/BMG
TO VFR/TEMPO MVFR FOR THE REMAINDER OF THE NIGHT. MAY NEED
ADDITIONAL AMENDMENTS FOR LOWER CONDITIONS IF MORE CLEARING
OCCURS...BUT THIS APPEARS UNLIKELY AT THE MOMENT. PREVIOUS
DISCUSSION FOLLOWS.

ISSUED AT 1241 AM EDT SAT MAY 18 2013

UPPER TROUGH WILL MOVE EAST ACROSS SOUTHERN INDIANA TONIGHT AND
SATURDAY MORNING. WOULD NOT RULE OUT ISOLATED SHOWERS OVERNIGHT AND
ISOLATED TO SCATTERED THUNDERSTORMS AFTER 15Z AS NORTHWEST FLOW
ALOFT DRAWS THE QUASI-STATIONARY SURFACE FRONT SOUTH TO NEAR A
BMG-HUF LINE BY 12Z AND SOUTH OF THE TERMINALS BY 00Z...AND MODELS
SHOW PLENTY OF INSTABILITY. HOWEVER...NO MAJOR FORCING...SO WILL GO
DRY UNTIL 15Z AND THEN VCTS FROM 15Z-20Z AT LAF AND HUF AND 22Z AT
IND AND BMG.

STILL COULD SEE SOME MVFR OR WORSE FOG AND OR CEILINGS AFTER
08Z...BUT IF THICK AC CAN HANG AROUND...IT COULD PREVENT THAT.
CONFIDENCE MEDIUM TO LOW ON MVFR OR WORSE CONDITIONS 08Z-13Z.

LIGHT TO CALM EAST AND SOUTHEAST WINDS TONIGHT SHOULD BE MOSTLY EAST
ON SATURDAY TO THE NORTH OF THE FRONT ESPECIALLY AT IND AND LAF. HUF
AND BMG MAY NOT SEE A WIND SHIFT UNTIL AFTERNOON. AT ANY
RATE...WINDS SHOULD BE LESS THAN 10 KNOTS DURING THE DAYTIME AND
LIGHT TO CALM AT NIGHT.

&&

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

&&

$$

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

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