Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 260809
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
409 AM EDT WED AUG 26 2015

.SYNOPSIS...
ISSUED AT 405 AM EDT TUE AUG 25 2015

LINGERING CLOUDS ASSOCIATED WITH A DEEP LOW PRESSURE AREA WILL
PERSIST THROUGH THE AT LEAST MIDDAY. A FEW SPRINKLES OR LIGHT
SHOWERS ARE POSSIBLE...ESPECIALLY OVER FAR NORTHERN INDIANA AND
SOUTHERN LOWER MICHIGAN. IT WILL REMAIN COOL...AS HIGHS ONLY REACH
THE UPPER 60S TO AROUND 70. LOWS TONIGHT WILL FALL BACK INTO THE
LOWER 50S.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 404 AM EDT WED AUG 26 2015

HIGHLY AMPLIFIED MID/UPR FLOW ACROSS CONUS AT PRESENT
CHARACTERIZED BY TX PANHANDLE TO ERN MT RIDGE BETWIXT SHARP/SLOWLY
EXITING TROF ACROSS SERN CANADA INTO LOWER GREAT LAKES AND 140W
CENTERED TROF. WHILE STRONG SHORTWAVE TO OVERTOP/DERIDE UPSTREAM
RIDGE OVER NEXT 24 HOURS...LOW LEVEL FLOW/TEMPERATURE PROFILES TO
REMAIN LARGELY STATUS QUO TODAY/TONIGHT. MINOR CHANGES TO ONGOING
FORECAST INCLUDE...SLIGHT LOWERING OF TEMPS THROUGH TODAY ALONG WITH
INCREASED CLOUD COVER/LOW POP AND/OR SPRINKLES MENTION ACROSS
NORTHERN TIER. 925-8H RIDGE WELL UPSTREAM OVER MISSOURI RIVER VALLEY
TO MAKE ONLY SLIGHT EWD PROGRESS TODAY. MAINTENANCE OF STRATOCU
APPEARS FAVORABLE WITH CYCLONIC LOW LEVEL FLOW INTO MIDDAY/AFTN
BEFORE WANING. FURTHERMORE...CORE OF THERMAL TROF THROUGH CWA AND
UPSTREAM MID LEVEL SHORTWAVES ENTERING BASE OF TROF BODES WELL FOR
SLOWER CLEARING TREND. CLOUD COVER TO QUICKLY DERIDE THIS EVENING AS
DEEP LAYER SUBSIDENCE OVERWHELMS AMID RELAXING LOW LEVEL FLOW.
SELECTIVE DOWNWARD NUDGES TO MIN TEMPS IN FAVORED DRAINAGE REGIONS
INCLUDING LAKESHORE/KBEH/KOXI/KGSH SITES.

&&

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 404 AM EDT WED AUG 26 2015

LOW LEVEL THERMAL TROUGHING WILL HOLD FOR ONE MORE DAY ON
THURSDAY...AS UPPER LEVEL TROUGHING BEGINS TO DEPART THE OHIO
VALLEY. LOW LEVEL AIR MASS WILL CONTINUE TO MODIFY THURSDAY AS MID
LEVEL HEIGHTS BEGIN TO RISE. DIURNALLY ENHANCED STRATOCU APPEARS
TO BE MOST LIKELY ACROSS EASTERN AREAS...BUT OTHERWISE A GOOD DEAL
OF INSOLATION IS EXPECTED FOR THE REMAINDER OF THE AREA. TAKING
THE ABOVE FACTORS INTO ACCOUNT...EXPECTING AT LEAST A COUPLE OF
DEGREES OF MODERATION IN COMPARISON TO WEDNESDAY...WITH HIGHS
GENERALLY IN THE UPPER 70S. DRY AIR MASS IN PLACE/CLEAR SKIES WILL
ALLOW FOR IDEAL RADIATIONAL COOLING CONDITIONS ONCE AGAIN THURSDAY
NIGHT WITH LOWS DROPPING WELL INTO THE 50S.

FOR FRIDAY-SUNDAY ATTENTION WILL TURN TO UPPER LEVEL TROUGH EJECTING
OUT OF BAJA OF CALIFORNIA REGION. THIS TROUGH SHOULD GET REINFORCED
BY AN UPPER PV ANOMALY DROPPING SOUTHEAST OUT OF NORTHERN STREAM.
THIS CONSOLIDATED PV ANOMALY IS THEN EXPECTED TO AFFECT THE LOCAL
AREA FOR THE FRIDAY NIGHT-SUNDAY PERIOD...ALTHOUGH VARIOUS
DETERMINISTIC SOLUTIONS STILL EXHIBITING QUITE A SIGNIFICANT SPREAD
IN TERMS OF STRENGTH OF THIS FEATURE WHICH IS SOMEWHAT DEPENDENT ON
EXTENT OF UPSTREAM PHASING. NONETHELESS...AN UPSWING IN ISENTROPIC
LIFT IS EXPECTED LATE FRIDAY AFTERNOON/NIGHT IN ADVANCE OF THIS
TROUGH. LOW LEVEL MOISTURE IS EXPECTED TO REMAIN RATHER MEAGER INTO
FRIDAY NIGHT AS MORE VEERED LOW LEVEL FLOW MAY INITIALLY NOT BE
EFFECTIVE IN SUBSTANTIAL MOISTURE TRANSPORT GIVEN HISTORY OF
SYNOPTIC SUBSIDENCE OF UPSTREAM AIRMASS. THUS...HAVE OMITTED THUNDER
FROM FRIDAY NIGHT AND JUST MAINTAINED LOW CHANCE SHRA POPS ACROSS
THE NORTH IN ASSOCIATION WITH ISENTROPIC FORCING.

UNSETTLED PATTERN TO CONTINUE SATURDAY/SUNDAY AS THIS PV ANOMALY
SLOWLY ERODES/ATTENUATES ACROSS THE REGION. BEST CHANCES OF THUNDER
SHOULD BE SATURDAY AFTERNOON ACROSS THE EAST...ALTHOUGH SOME ISOLD
THUNDER CANNOT BE RULED OUT THROUGH MOST OF THE UPCOMING WEEKEND.
IMPACTS OF CLOUDS/SCT SHOWERS SHOULD LIMIT HIGHS TO UPPER 70S OR
AROUND 80.

NO MAJOR CHANGES FOR THE REMAINDER OF FORECAST WITH UPPER RIDGING
BUILDING BACK ACROSS THE REGION AND A STEADY WARMING TREND THROUGH
THE MIDDLE OF NEXT WEEK.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 202 AM EDT WED AUG 26 2015

CEILINGS HEIGHTS CONTINUE TO LOWER ACROSS SOUTHERN MI AND FAR
NORTHERN IN WITHIN CORE OF DEEP COLD AIR IN CONCERT WITH NOCTURNAL
COOLING AND ADDITIVE LAKE MOISTURE EFFECTS. APPROACH OF WEAK
SHORTWAVE TOWARD DAYBREAK SHOULD ILLICIT INCREASE LIGHT SHRA
COVERAGE NEAR AND NORTHWEST-NORTH OF KSBN AND ADDED NOMINAL
INCLUSION THOUGH NO ANTICIPATED REDUCTION TO VISIBILITY. SOUTHERN
FRINGE OF HIGH END MVFR CLOUDS MAY BRIEFLY SETTLE INTO KFWA
VCNTY NEAR/SHORTLY AFTER DAYBREAK...HOWEVER EXTREMELY LOW CHANCE
OF BECOMING SIGNIFICANT...AT/BELOW 2KFT AGL...AND HAVE MAINTAINED
MORE PROBABLE VFR CONDITIONS.

&&

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

$$

SYNOPSIS...MURPHY
SHORT TERM...MURPHY
LONG TERM...MARSILI
AVIATION...MURPHY


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