Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 212353
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
753 PM EDT THU MAY 21 2015

.SYNOPSIS...
ISSUED AT 753 PM EDT THU MAY 21 2015

VARIABLE CLOUD COVER OVERNIGHT AS A WEAK FRONT DROPS SOUTH
THROUGH THE REGION...WITH JUST A SMALL CHANCE OF SOME BRIEF
SPRINKLES OVERNIGHT. LOWS TONIGHT WILL BE IN THE MIDDLE TO UPPER
40S. SKIES WILL BECOME MOSTLY SUNNY ON FRIDAY WITH HIGHS INTO THE
MIDDLE 60S TO AROUND 70...EXCEPT COOLER NEAR LAKE MICHIGAN.

&&

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 257 PM EDT THU MAY 21 2015

QUIET/SEASONABLY COOL WX WILL PERSIST THIS PERIOD IN NW FLOW AS
JAMES BAY NEGATIVE HEIGHT ANOMALY DROPS INTO SOUTHERN QUEBEC.
VORT LOBE ROTATING THROUGH THE SOUTHWEST FRINGE OF THIS FEATURE
WILL DROP A WEAKENING COLD FRONT THROUGH THE AREA LATER TONIGHT.
DECENT CONVERGENCE/LAPSE RATES NOTED IN THE NORTH BUT EXPECTING
NOTHING MORE THAN ISO-SCT SPRINKLES/LIGHT SHOWERS AT BEST ACROSS
NORTHERN/EASTERN ZONES LATER TONIGHT GIVEN SHALLOW MOISTURE/LIFT.
DRY/MAINLY CLEAR OTHERWISE POST FRONTAL TOMORROW WITH DEEP
MIXING/AMPLE SUNSHINE LIKELY ENOUGH TO OFFSET WEAK CAA...WHICH
SHOULD ALLOW AFTERNOON HIGHS TO MAKE A RUN AT THE MID-UPPER 60S
(COOLER NEAR LAKE MI).

&&

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 257 PM EDT THU MAY 21 2015

WATER VAPOR SHOWS UPPER LOW OFF THE WEST COAST THIS AFTERNOON AND
THIS WILL BE OUR MAIN IMPACT PLAYER FOR LATER IN THE HOLIDAY
WEEKEND THROUGH THE MIDDLE PART OF NEXT WEEK. UPPER TROUGH TO
DRIFT INTO WESTERN CONUS WHILE HEIGHTS RISE OVER OUR AREA AND
SOUTHWEST FLOW DEVELOPS. THIS WILL LEAD TO SLOW WARMING TREND
ALONG WITH INCREASING HUMIDITY. SHORT WAVE RIDGING ALONG WITH SFC
HIGH TO OUR EAST SHOULD KEEP THE AREA DRY UNTIL AT LEAST SUNDAY.
AS WE HAVE DISCUSSED FOR DAYS...MODELS WERE INITIALLY OVERDONE
WITH QPF AND CONVECTIVE DEVELOPMENT AND ARE CONTINUING TO TREND
SLOWER WITH LESS COVERAGE ASSOCIATED WITH LEAD SHORT WAVES. HAVE
CONTINUED TO SCALE POPS BACK FOR SATURDAY NIGHT AND EARLY SUNDAY
AND CONFINED JUST TO THE WESTERN THIRD SUNDAY MORNING.

BY LATER SUNDAY INTO MONDAY HEIGHTS BEGIN TO FALL AS UPPER TROUGH
INCHES CLOSER. BETTER LOW LEVEL MOISTURE IN PLACE AND SCATTERED
SHOWERS AND THUNDERSTORMS BECOME MORE LIKELY WITH ANY SHORT
WAVES...ESPECIALLY WEST. WILL KEEP LIKELY POPS CONFINED TO WEST
AND NORTH WHERE BETTER FORCING AND MOISTURE WILL COEXIST AND
LEAVE CENTRAL AND EASTERN AREAS IN CHANCE CATEGORY.

TROUGH WILL OPEN AND FILL AS IT MOVES EAST BUT WEAK QUASI
STATIONARY BOUNDARY LIKELY WILL BE LEFT BEHIND IN THE GREAT LAKES
OR MIDWEST REGION. EXPECT SOME CONVECTIVE DEVELOPMENT AND
POSSIBLE MCS ACTIVITY WHICH COULD IMPACT OUR AREA. BROAD CHANCE
POPS THROUGH END OF PERIOD GIVEN THIS SETUP BUT AGAIN...EXPECT
SCATTERED CONVECTION AND MANY HOURS OF DRY TIME.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 750 PM EDT THU MAY 21 2015

VFR MET CONDS THROUGH THE FORECAST PD WITH PRIMARY ATTENTION TO
SFC WIND DIRECTIONS. ANTICIPATE EVENING SFC FLOW TO BACK
CONSIDERABLY/SHORTLY AHEAD OF E-W TROUGH AXIS MOVG SWD THROUGH
THE GREAT LAKES. SHARPLY VEERED FLOW IN WAKE OF PASSAGE TOWARD
DAYBREAK...EXCEPT ANTICIPATE SOME LATER BACKING/NWLY FLOW SHIFT
AT KSBN DUE TO RAMPING LAKE BREEZE INFLUENCE. SPRINKLES FROM AM
MIDDECK LOW AND OMITTED GIVEN LOW PROB/ANTICIPATED ISOLD COVERAGE
AT BEST.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&

$$

SYNOPSIS...MURPHY
SHORT TERM...STEINWEDEL
LONG TERM...LASHLEY
AVIATION...MURPHY


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