Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 191912
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
312 PM EDT TUE MAY 19 2015

.SYNOPSIS...
ISSUED AT 124 PM EDT TUE MAY 19 2015

A RIDGE OF HIGH PRESSURE WILL SETTLE ACROSS THE WESTERN GREAT
LAKES REGION TONIGHT PROVIDING DIMINISHING WINDS...ALLOWING LOW
TEMPERATURES TONIGHT TO RANGE FROM THE MID 30S ACROSS SOUTH
CENTRAL LOWER MICHIGAN...TO THE UPPER 30S AND LOWER 40S ACROSS
MUCH OF NORTHERN INDIANA AND NORTHWEST OHIO. SOME PATCHY FROST IS
POSSIBLE LATE TONIGHT INTO EARLY WEDNESDAY MORNING ACROSS NORTHERN
INDIANA...EXTREME NORTHWEST OHIO AND SOUTHERN LOWER MICHIGAN.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 307 PM EDT TUE MAY 19 2015

STRATOCU DECK SLOW TO MIX OUT THIS AFTERNOON IN NW FLOW/CAA
REGIME...AS BROAD S/W TROF EXITS EAST OUT OF THE EASTERN GREAT LAKES
THROUGH THIS EVENING. EXPECTING CLOUDS TO SCATTER OUT TOWARD 00Z
ACROSS THE AREA AS DRIER AIR ADVECTS INTO THE REGION. AS
AFOREMENTIONED TROF EXITS INTO SE ONTARIO/QUEBEC...A MORE ZONAL FLOW
REGIME WILL DOMINATE ACROSS THE AREA OVERNIGHT...WILL SFC RIDGING
CENTERED ACROSS THE UPPER MIDWEST NOSES E/SE INTO THE AREA. COLD
AIRMASS IN PLACE WITH DRYING LOW LEVELS DOES RAISE SOME CONCERNS FOR
TEMPS FALLING INTO THE MID 30S OVERNIGHT WITH PATCHY FROST POSSIBLE.
TWO KEY THINGS ARE WORKING AGAINST WIDESPREAD FROST DEVELOPMENT.
FIRST...UPPER LEVEL CLOUDS EXPECTED TO SPILL OVER THE REGION THROUGH
THE OVERNIGHT IN ADVANCE OF EJECTING CENTRAL PLAINS LOW PRESSURE.
THIS WILL LIMIT SIGNIFICANT RADIATIONAL COOLING ACROSS THE AREA.
SECOND...EXPECTING SOME GRADIENT FLOW OVERNIGHT AS SFC HIGH CENTER
REMAINS NW OF THE FORECAST AREA. THERE COULD BE SOME BL DECOUPLING
ACROSS THE FAR NW PART OF THE FORECAST AREA...WITH LIGHTER
WINDS...HOWEVER WESTERN AREAS ARE EXPECTED TO HAVE THE MOST UPPER
CLOUD COVER AS THE NEXT SYSTEM APPROACHES. OVERALL FEELING IS THAT
FROST POTENTIAL IS MARGINAL...AND ANY DEVELOPMENT WILL MAINLY BE IN
ISOLATED/LOW LYING AREAS. THEREFORE...WILL OPT AGAINST ANY FROST
HEADLINES FOR THIS FORECAST ISSUANCE...HOWEVER HAVE EXPANDED MENTION
OF PATCHY FROST IN THE ZONES SOUTH AND WESTWARD ACROSS THE AREA
FROM THE PREVIOUS FORECAST MENTION. WILL ALSO MENTION PATCHY FROST
POTENTIAL IN HWO. AS FAR AS TEMPERATURES GO...WENT WITH A BIAS
CORRECTED MOS GUIDANCE BLEND FOR TEMPERATURES...WHICH HAS
PERFORMED WELL IN SIMILAR REGIMES OVER THE PAST SEVERAL WEEKS.
THIS IS YIELDING TEMPS IN THE 37 TO 38 DEGREE RANGE IN AREAS WHERE
PATCHY FROST IS MENTIONED...WITH ISOLATED SPOTS DROPPING TO 35-36
DEGREES...ESPECIALLY ACROSS NORTHERN BERRIEN AND NW CASS COUNTIES.

SHEARING S/W WILL EJECT OUT OF PLAINS WEDNESDAY AND TRACK TOWARD THE
REGION. PRECIP CHANCES WILL INCREASE FROM WEST TO EAST ACROSS THE
AREA LATE MORNING THROUGH THE AFTERNOON. DECENT FORCING/MID LEVEL
ASCENT AND 700-500MB MOISTURE ADVECTION WILL HAVE TO OVERCOME RATHER
DRY SUB 700MB LAYER AND E/NE FLOW REGIME. OVERALL...SLOWED DOWN THE
ARRIVAL OF POPS DURING THE LATE MORNING/EARLY AFTERNOON HOURS...WITH
THE BEST CHANCES ACROSS THE SW PART OF THE FORECAST AREA. NO MAJOR
CHANGES TO MAX TEMPS ON WEDNESDAY.

&&

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 307 PM EDT TUE MAY 19 2015

LONG TERM BEGINS RELATIVELY QUIET AND BENIGN BUT LATTER HALF OF
FORECAST BECOMES MORE ACTIVE ONCE AGAIN.

SOUTHERN STREAM WAVE WILL BE PASSING BY TO OUR SOUTH AT BEGINNING OF
PERIOD WEDNESDAY EVENING. ELONGATED HIGH PRESSURE RIDGE AT SURFACE
TO LIKELY KEEP MUCH OF THE AREA DRY. ENOUGH MOISTURE AND WEAK LIFT
ACROSS FAR SOUTHERN AREAS TO WARRANT CONTINUATION OF LOW CHANCE POPS
TAPERING OFF FURTHER NORTH. ANY PCPN AMOUNTS WILL BE
LIGHT...GENERALLY UNDER A TENTH OF AN INCH AND THAT WOULD ONLY BE IN
THE FAR SOUTH.

ANOTHER WEAK NORTHERN STREAM SHORT WAVE AND WEAK SFC FRONT WILL DROP
ACROSS THE REGION THU NIGHT. MOISTURE VERY LIMITED AND FOR NOW ONLY
GOING WITH A SUBTLE INCREASE IN CLOUDS OVER THE NORTHEAST. 850MB
TEMPS BEHIND THIS FRONT ACTUALLY MODIFY AND END UP BEING SLIGHTLY
WARMER THAN THU. WITH SUN ON FRIDAY EXPECT TEMPS MOST AREAS TO BE A
FEW DEGREES WARMER WITH EXCEPTION MAYBE IN THE FAR NORTHEAST WHERE
FRI HIGHS WILL BE SIMILAR TO THU.

WARMING TREND CONTINUES INTO THE WEEKEND WITH HIGH PRESSURE DRIFTING
ACROSS THE AREA. SUPERBLEND NUMBERS REASONABLE AND ACCEPTED. PATTERN
ONCE AGAIN SHIFTS BACK TO SOUTHWEST FLOW DURING LATTER HALF OF
WEEKEND INTO NEXT WEEK. UPPER LOW DRIFTS INTO CENTRAL PLAINS WHILE
WARM AND MOIST SOUTHWEST FLOW DEVELOPS AHEAD OF IT FOCUSED INTO OUR
REGION. MOIST AND UNSTABLE CONDITIONS EXPECTED WHICH WILL SET THE
STAGE FOR SCATTERED SHOWERS AND THUNDERSTORMS ONCE AGAIN. LIKE THIS
PAST WEEK AND WEEKEND...COVERAGE AND TIMING REMAINS QUESTIONABLE
GIVEN COMPLICATED CONVECTIVE NATURE SO CONTINUED TO CONFINE POPS TO
HIGH CHANCE RANGE SHY OF SUPERBLEND LIKELY CATEGORY FOR SEVERAL
PERIODS. YES THERE WILL BE ROUNDS OF PCPN BUT CONFIDENCE IN DURATION
AND SPECIFIC PERIODS REMAIN LOW AND THUS ACTUAL 12 HOUR POP REMAINS
BELOW 60 PERCENT. MORE DETAIL ADDED AS TIME NEARS. TIMING OF ACTUAL
PCPN AND CLOUD COVER WILL ALSO IMPACT TEMPS NEXT WEEK. POTENTIAL FOR
WARMER TEMPS EXIST BUT PREFER TO STAY IN MIDDLE OF ROAD WITH
POPULATED SUPERBLEND FOR NOW.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 120 PM EDT TUE MAY 19 2015

EXPANSIVE STRATOCU DECK WILL CONTINUE TO GRADUALLY LIFT EARLY IN
THE TAF PD...AND SCATTER OUT CLOSER TO 00Z AT TERMINALS. SOME HIGH
END MVFR CIGS POSSIBLE IN THE FIRST FEW HOURS OF THE
PERIOD...ESPECIALLY AT KSBN...ELSE VFR CIGS EXPECTED. GUSTY NW
WINDS WILL SUBSIDE TOWARD 00Z...SLOWLY VEERING N-NE THROUGH THE
END OF THE PD. LOW END -RA CHANCES RETURN TOWARD THE END OF THE
TAF PD...PRIMARILY AT KFWA...HOWEVER CONFIDENCE TOO LOW TO INCLUDE
IN FCST ATTM.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...BEACH HAZARDS STATEMENT UNTIL 4 PM CDT THIS AFTERNOON FOR INZ003.

MI...BEACH HAZARDS STATEMENT UNTIL 5 PM EDT THIS AFTERNOON FOR MIZ077.

OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR LMZ043-
     046.

&&

$$

SYNOPSIS...MARSILI/NG
SHORT TERM...NG
LONG TERM...LASHLEY
AVIATION...NG


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