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000
FXUS63 KIND 232047
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
447 PM EDT THU MAY 23 2013

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

&&

.SYNOPSIS...
ISSUED AT 300 PM EDT THU MAY 23 2013

UPPER TROUGH ACROSS THE LOWER GREAT LAKES WILL MOVE SOUTHEAST ACROSS
THE APPALACHIANS ON FRIDAY AS COOL CANADIAN HIGH PRESSURE SETTLES
ACROSS THE GREAT LAKES AND OHIO VALLEY. THIS WILL RESULT IN CLEARING
TONIGHT WITH BELOW TEMPERATURES THROUGH THE MEMORIAL DAY WEEKEND.
SHOWER CHANCES WILL RETURN BY SATURDAY. TEMPERATURES WILL RETURN TO
NEAR NORMAL MEMORIAL DAY AND ABOVE NORMAL BY MIDWEEK NEXT WEEK.
THUNDERSTORM CHANCES WILL ALSO RETURN NEXT WEEK AS GULF MOISTURE
SPREADS NORTH ACROSS THE OHIO VALLEY.

&&

.NEAR TERM /TONIGHT/...
ISSUED AT 300 PM EDT THU MAY 23 2013

MAIN CHALLENGES TONIGHT WILL BE TIMING OF END OF SHOWERS...CLEARING
AND FINALLY TEMPERATURES AS AN UPPER LOW DROPS SOUTHEAST ACROSS THE
LOWER GREAT LAKES AND COOL CANADIAN HIGH SURFACE BUILDS IN BEHIND A
COLD FRONT.

MODELS IN GOOD AGREEMENT ON DROPPING AN UPPER TROUGH...ACROSS THE
WESTERN GREAT LAKES THIS AFTERNOON...TO LAKE ERIE BY FRIDAY MORNING.
IN ADDITION...COOL CANADIAN HIGH PRESSURE WILL BUILD IN BEHIND A
COLD FRONT THAT WAS PRESENTLY NEAR AN IND-HUF LINE. THIS WILL ALLOW
CLEARING FROM NORTHWEST TO SOUTHEAST AS WELL AS AN END TO THE
SHOWERS. THE SHOWERS SHOULD ONLY HANG AROUND TIL DARK ACROSS OUR
EASTERN COUNTIES...SO PULLED SLIGHT CHANCE SHOWER POPS AFTER 02Z.
LEANED TOWARD THE COLDER 12Z NAM MOS WHICH WAS BRINGING OVERNIGHT
LOWS IN THE UPPER 30S ACROSS OUR NORTHWEST OVERNIGHT AND 40S
ELSEWHERE. NORTHWEST WINDS WILL DROP TO BELOW 10 KNOTS AT DARK AS
WELL.

&&

.SHORT TERM /FRIDAY THROUGH SUNDAY/...
ISSUED AT 300 PM EDT THU MAY 23 2013

MAIN FOCUS TO THE SHORT TERM WILL BE ON POPS FOR THE MEMORIAL DAY
WEEKEND WITH SO MANY OUTDOOR ACTIVITIES ON TAP.

MODELS IN GOOD AGREEMENT ON COOL CANADIAN HIGH PRESSURE...KEEPING
TEMPERATURES BELOW NORMAL THROUGH THE WEEKEND AS UPPER RIDGE CAMPS
OUT ACROSS THE PLAINS. MODEL TIME SECTIONS SUGGEST CLEAR SKIES
FRIDAY AND FRIDAY NIGHT WITH A DRY COLUMN AND HIGH PRESSURE IN
PLACE. HOWEVER...MODELS IN AGREEMENT ON BRINGING QPF TO ALL OR PARTS
OF CENTRAL INDIANA SATURDAY THROUGH SUNDAY AS UPPER WAVES TOP THE
CENTRAL RIDGE AND DROP SOUTHEAST ACROSS CENTRAL INDIANA. IN
ADDITION...305K ISENTROPIC LIFT WILL BE PLACE WITH INCREASING
MOISTURE. THUS...WILL ADD SMALL POPS SATURDAY AND SATURDAY NIGHT
ACROSS ALL BUT NORTHEASTERN PARTS OF THE FORECAST AREA AND RAISE
POPS SLIGHTLY ON SUNDAY WITH GENERALLY CHANCE POPS WEST OF
INTERSTATES 69 AND 65 AND SLIGHT CHANCE POPS EAST. GULF MOISTURE
DOES NOT START INCREASING UNTIL EARLY NEXT WEEK...AND MODEL TIME
SECTIONS ALSO REVEAL DRY AIR BELOW 850 MILLIBARS. SO...AM
COMFORTABLE WITH THE LOWER ALLBLEND POPS. WOULD NOT RULE OUT THUNDER
SUNDAY...BUT BEST INSTABILITY WILL BE WEST OF CENTRAL INDIANA.

ALLBLEND TEMPERATURES RESEMBLE THE CLOSE MOS AND LOOK REASONABLE
WITH THE COOL CANADIAN AIR POISED TO HANG AROUND.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
ISSUED AT 152 AM EDT THU MAY 23 2013

MODELS ARE SIMILAR ENOUGH FOR THE MOST PART THAT THE ALL BLEND
INITIALIZATION WAS USED FOR MOST ITEMS.

A WARM FRONT WILL REMAIN IN THE NEIGHBORHOOD EARLY IN THE
EXTENDED...WHICH WILL ALLOW SOME SHOWERS AND THUNDERSTORMS TO
DEVELOP. LOCATION OF FRONT AND TIMING OF ITS MOVING NORTHEAST
REMAINS SOMEWHAT UNCERTAIN...SO RELUCTANTLY KEPT LOW POPS IN SUNDAY
NIGHT INTO WEDNESDAY /EVEN THOUGH IT LIKELY WILL NOT RAIN EACH
PERIOD/. RIDGING WILL THEN BUILD IN FOR THE END OF THE PERIOD.

TEMPERATURES WILL WARM THROUGH THE PERIOD AS THE FRONT LIFTS
NORTHEAST AND UPPER RIDGING BUILDS IN.

&&

.AVIATION /DISCUSSION FOR 232100Z TAF UPDATE/...

ISSUED AT 447 PM EDT THU MAY 23 2013

MOST OF THE SCATTERED CONVECTION HAS SHIFTED SOUTH OF I-70 WITH ONLY
POSSIBLE IMPACT AT KBMG AND EVEN THERE THE RAIN THREAT WILL END BY
22Z. STILL AN ABUNDANCE OF LOW STRATOCU. TWEAKED CEILINGS AND WINDS
BASED ON CURRENT OBS.

18Z DISCUSSION FOLLOWS.

GENERALLY MVFR CONDITIONS THROUGH ABOUT THE FIRST HALF OF THE TAF
PERIOD...THEN VFR.

EXTENSIVE MVFR AND PATCHY IFR CONDITIONS EXIST BEHIND A SURFACE
BOUNDARY THAT WILL HAVE PASSED MOST TAF SITES BY SHORTLY AFTER VALID
TIME. MOST CEILINGS ARE BELOW BKN020...SO WILL KEEP CEILINGS THAT
LOW FOR MUCH OF THE AFTERNOON. CANNOT RULE OUT BRIEF PERIODS OF IFR
OR VFR AS CEILINGS BOUNCE AROUND EARLY IN THE PERIOD.

WILL ALLOW A SLOW RISE THROUGH THE MVFR CATEGORY FROM LATE AFTERNOON
INTO THE EVENING HOURS AS TROUGH AXIS EXITS. CLEARING SHOULD WORK IN
LATE EVENING INTO THE EARLY OVERNIGHT. HIGH PRESSURE WILL THEN BUILD
IN AND PROVIDE CLEAR SKIES FOR FRIDAY.

WINDS BECOME GUSTY NORTHWEST TO AROUND 20 MPH BEHIND THE BOUNDARY
AND THESE CONDITIONS SHOULD CONTINUE THROUGH 00Z OR SO.

&&

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

&&

$$

SYNOPSIS...MK
NEAR TERM...MK
SHORT TERM...MK
LONG TERM....50
AVIATION...50/RYAN

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