Area Forecast Discussion
Issued by NWS Northern Indiana

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037
FXUS63 KIWX 261959
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
359 PM EDT TUE APR 26 2016

.SYNOPSIS...
ISSUED AT 400 PM EDT TUE APR 26 2016

DRY AND COOL AIR FILTERING INTO THE REGION WILL ALLOW TEMPERATURES
TO DIP INTO THE 40S OVERNIGHT. MOSTLY CLOUDY CONDITIONS OVERNIGHT
WILL GIVE WAY TO SOME SUN ON WEDNESDAY WITH TEMPERATURES WARMING
INTO THE 60S. A CHANCE OF SHOWERS AND THUNDERSTORMS RETURN IN THE
AFTERNOON FOR NORTHERN INDIANA. MOST AREAS WILL THEN HAVE SHOWERS
AND A FEW THUNDERSTORMS WEDNESDAY NIGHT.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 347 PM EDT TUE APR 26 2016

FRONTAL BOUNDARY WELL SOUTH OF CWA WITH STRONG LOW LEVEL THETA-E
SUPPRESSION TO MAINTAIN DRY FORECAST WITH E/W ORIENTED SURFACE BASED
CONVECTION ALONG/S I70 CORRIDOR THIS EVENING/OVERNIGHT. SUSPECT
LATENT SUBSIDENCE INVERSION/SHALLOW NATURE OF POST FRONTAL MOISTURE
SCOUR AND WELL MIXED BOUNDARY LAYER TO BECOME FOCUS FOR STRATUS
REFORMATION/SWD EXPANSION LATE TONIGHT AND MAINTAIN SLIGHTLY WARMER
SFC TEMPS/CLOSER TO BLEND. ALSO HAVE RELEGATED POPS MUCH LATER TO
PRIMARILY LATE AFTERNOON GIVEN TEMPORARY MID LEVEL LOW AMPLITUDE
RIDGING AS COMPLEX CENTRAL ROCKIES/SWRN STATES VORTEX LIFTS THROUGH
PLAINS/TOWARDS MID MS VLY IN HIGHLY NEG TILT FASHION. HIEST POPS IN
SWRN CWA LATE AFTERNOON IN PROXIMITY TO STRONGEST 1000-850MB
MOISTURE FLUX CONVERGENCE...THOUGH CONVECTION TO REMAIN QUITE
ELEVATED/NON SEVERE OWING TO COOL BACKED LOW LEVEL FLOW.

&&

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 347 PM EDT TUE APR 26 2016

BEST SURGE OF 295-300K ISENTROPIC UPGLIDE WILL ARRIVE WEDNESDAY
NIGHT. BETTER PRECIP CHANCES ALSO SUPPORTED BY LOW-MIDLEVEL THETA-E
ADVECTION WEDNESDAY EVENING AS MIDLEVEL RIDGE AXIS SHIFTS EASTWARD
AND BETTER S/SW FLOW DEVELOPS ALOFT. EMBEDDED VORTICITY LOBE WILL
ALSO LIFT THROUGH THE AREA EARLY THURSDAY MORNING AND COMBINATION OF
THESE FACTORS SHOULD SUPPORT WIDESPREAD LIGHT RAIN DESPITE DRY
EASTERLY FLOW AT THE SURFACE. THIS IS ESPECIALLY TRUE IN OUR W/SW
COUNTIES WHERE CATEGORICAL POPS MAINTAINED. CHANCES NOT AS HIGH IN
OUR NE WHERE LINGERING HIGH PRESSURE AND LOW LEVEL DRY AIR MAY EAT
INTO PRECIP AMOUNTS A BIT. SCT SHOWERS WILL THEN CONTINUE THROUGH
THURSDAY AND THURSDAY NIGHT AS MAIN PV ANOMALY OPENS UP AND SHEARS
EASTWARD. FORCING BECOMES RATHER MUDDLED DURING THIS PERIOD BUT
STILL EXPECT PERIODIC LIGHT SHOWERS WITH THE BEST CHANCES ALONG
EVENTUAL TRACK OF DECAYING VORT MAX. SOME ISOLATED THUNDER POSSIBLE
GIVEN A FEW HUNDRED J/KG OF ELEVATED CAPE BUT WILL NOT BE WIDESPREAD
AND NO SEVERE WEATHER IS EXPECTED. ANOTHER TIGHT TEMP GRADIENT
EXPECTED ON THURSDAY WITH SURFACE FRONT DRAPED OVER OUR AREA.
MICHIGAN REMAINS LOCKED UNDER INVERSION WITH TEMPS ONLY IN THE LOW
50S WHILE OUR SOUTHERN COUNTIES MIX OUT TO LOW 70S. HIGH BUST
POTENTIAL EITHER WAY DEPENDING ON WHERE EXACTLY FRONT SETS UP.

DRY CONDITIONS EXPECTED ON FRIDAY BUT WILL BE SHORT-LIVED. SECOND
TROUGH...CURRENTLY DIGGING INTO THE PACIFIC NORTHWEST...WILL EJECT
EASTWARD IN ALMOST IDENTICAL FASHION TO MIDWEEK SYSTEM. ANOTHER
SURGE OF MOIST ISENTROPIC ASCENT EXPECTED LATE SATURDAY WITH RAIN
CHANCES CONTINUING THROUGH SUNDAY AS MIDLEVEL VORT MAX SHEARS EAST.
12Z MODEL SUITE IN BETTER AGREEMENT BUT EVENT IS STILL SEVERAL DAYS
OUT AND STILL CURRENTLY OVER THE DATA-SPARSE NORTH PACIFIC. RAISED
POPS A BIT BUT FURTHER ADJUSTMENTS ARE POSSIBLE. ALSO SIMILAR TO
MIDWEEK...SOME THUNDER POSSIBLE BUT CHANCES LOW GIVEN CURRENT
FORECAST TRACK/POSITION OF SURFACE FEATURES. HIGH TEMPS REMAIN JUST
SLIGHTLY ON THE COOL SIDE OF CLIMO AND NO FROST CONCERNS AT THIS
POINT.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 135 PM EDT TUE APR 26 2016

DIFFICULT FORECAST FOR NORTHERN INDIANA AND HAVE SIDED MORE
PESSIMISTIC WITH RESPECT TO DURATION OF STRATUS LAYER. COLD AIR
ADVECTION INTO RICH LOW LEVEL MOISTURE TO LIKELY CONTINUE TO
SUPPORT WIDESPREAD IFR TO LOW END MVFR STRATUS DECK THROUGHOUT THE
UPPER GREAT LAKES. CHANCE OF SCATTERING OUT BRIEFLY THIS EVE AT
KSBN...THOUGH WITH TIME SATURATION BENEATH SUBSIDENCE INVERSION
AND PERSISTENT MIXING/NE-E CLOUD LAYER FLOW TO LIKELY LEND STRATUS
TO SOLIDIFY AND ADVANCE SWD INTO KFWA VCNTY AS WELL. HELD AOA 600
FT AND GENERALLY GOOD VSBYS AS ELEVATED STRATUS SUGGESTED BY
HRRR/NAM AND CONCEPTUAL MODEL. AS OPPOSED TO THIS MORNING/LIFT OUT
SHOULD BE SIGNIFICANTLY MORE RAPID WITH STRONGER
INSOLATION/TRANSITION TO LOW LEVEL WARM AIR ADVECTION.

&&

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

$$

SYNOPSIS...MURPHY
SHORT TERM...MURPHY
LONG TERM...AGD
AVIATION...MURPHY


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