Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 262020
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
420 PM EDT WED AUG 26 2015

.SYNOPSIS...
ISSUED AT 1109 AM EDT WED AUG 26 2015

SPRINKLES TO LIGHT SHOWERS ARE POSSIBLE TODAY IN NORTHERN INDIANA
SOUTHERN MICHIGAN AND NORTHWESTERN OHIO AS A LOW STILL ROTATES IN
CANADA AND HIGH PRESSURE IS TO THE NORTHWEST. THIS HIGH WILL MOVE
INTO THE REGION TONIGHT CLEARING UP THE SKIES. HIGH TEMPERATURES
TODAY WILL RANGE FROM THE UPPER 60S IN SOUTHERN MICHIGAN TO THE
MIDDLE 70S NEAR THE OHIO RIVER. LOWS TONIGHT WILL BE ON THE COOL
SIDE IN THE LOWER 50S.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 417 PM EDT WED AUG 26 2015

LONGWAVE PATTERN WITH RIDGE ACROSS THE WESTERN HALF OF THE CONUS AND
TROF CENTERED OVER THE GREAT LAKES TO THE GULF OF MEXICO SHOWS LITTE
IN THE WAY OF MAJOR CHANGE FOR THE NEXT 24 TO 36 HOURS. TROF IS
SHOWING SIGNS OF WEAKENING AND DAMPENING OUT...AS THE DEFORMATION
AXIS CONTINUES TO BE STRETCHED NORTEASTWARD. THE WESTERN RIDGE
REMAINS HIGHLY AMPLIFIED WITH SUBTLE HINTS OF THE RIDGE SHIFTING
SLIGHTLY EASTWARD BY THE END OF THE SHORT TERM.

LINGERING SHOWERS/SPRINKLES WILL PERSIST THROUGH SUNSET
TONIGHT...BEFORE THE DRIER AIR BEGINS TO FILTER IN. EXPECT TO SEE
CLEARING IN THE SOUTHWEST PORTION OF THE CWA...WITH CLOUDS ERODING
AND CLEARING SPREADING NORTHEAST OVERNIGHT. THIS CREATES ANOTHER
PROBLEM AND MODEL CROSSS SECTIONS AND BUFR SOUNDINGS STRONGLY
SUPPORT AND FAVOR FOG FORMATION. COMBINED WITH THE LIGHT RAINFALL
THAT FELL OVER THE PAST FEW HOURS...AND THE PUMP IS PRIMED FOR FOG
FORMATION. HAVE INCLUDED PATCHY/AREAS FOG BEGINNING AROUND 2 AM AND
CONTINUING THROUGH 8 OR 9 AM THURSDAY. THIS WILL NEED TO BE WATCHED
CLOSELY AS SOME OF THE HIGH RES MODELS WOULD SUPPORT DENSE FOG. THIS
WILL DEPEND ON THE AMOUNT OF CLEARING.

BETTER DAY WITH MORE SUNSHINE THEN CLOUD ON THURSDAY. ALSO EXPECT
TO SEE TEMPERATURES RISE APPRECIABLY OVER HIGHS TODAY.

&&

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 417 PM EDT WED AUG 26 2015

AN UPPER LEVEL TROF NEAR SALT LAKE CITY THIS AFTERNOON WAS ASCENDING
THE BACK SIDE OF THE UPPER LEVEL RIDGE OVER THE CENTRAL CONUS.
NCEP/WPC MODELS AND OTHER MODELS SEEMED TO HAVE INITIALIZED THIS
SYSTEM WELL. THE TROF IS EXPECTED TO TOP THE UPPER RIDGE THURSDAY
AND REACH THE FORECAST AREA EARLY THIS WEEKEND. MADE SOME MINOR
ADJUSTMENTS TO THE TIMING OF THE SHOWERS AND STORMS ASSOCIATED WITH
THIS SYSTEM BASED THE THE LATEST MODEL RUNS. OVERALL...MID LEVEL
LAPSE RATES SHOULD BE RELATIVELY STABLE AND BULK SHEAR SHOULD BE
WEAK...SO DO NOT EXPECT ANY STORMS TO BECOME SEVERE. THE UPPER
LEVEL RIDGE SHOULD CONTINUE TO BUILD INTO EARLY NEXT
WEEK...ALLOWING TEMPERATURES TO RISE ABOVE NORMAL. AFTER
COORDINATION WITH SURROUNDING OFFICES... RAISED HIGHS WELL INTO
THE 80S TUESDAY. MUCH UNCERTAINTY EXISTS WHERE TROPICAL STORM
ERICA WILL EVENTUALLY TRACK. THE LATEST NHC FORECAST INDICATED THE
SYSTEM BECOMING A HURRICANE NEAR MIAMI MONDAY MORNING. ALTHOUGH
STILL MUCH UNCERTAINTY...SOME CANADIAN AND GFS ENSEMBLES BRING
THIS SYSTEM INTO THE GULF OF MEXICO. IF ONE OF THESE TRACKS
VERIFIES...MOISTURE FROM ERICA MAY EVENTUALLY SPREAD NORTH OF THE
OHIO RIVER AND REACH THE FORECAST AREA NEXT WEEK.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 132 PM EDT WED AUG 26 2015

PERSISTENT LOW CLOUDS WRAPPING AROUND THE BOUNDARY LAYER TROF/SFC
LOW WILL CONTINUE TO CREATE WIDESPREAD MVFR AND ISOLATED IFR
CONDITIONS THROUGH THE EARLY EVENING. SATELLITE SHOWS YET ANOTHER
TROF/WAVE MOVING SOUTH ACROSS LAKE MI AND THIS APPEARS TO BE THE
FINAL PUSH OF COLD AIR. WITH LIGHT WINDS...DECREASING CLOUD COVER
TONIGHT AND VERY LIGHT SHOWERS EXPECT TO SEE NEARLY IDEAL
CONDITIONS FOR FOG FORMATION IN THE LATE OVERNIGHT/EARLY MORNING
THURS. HAVE INTRODUCED TEMPO IFR CONDITIONS FOR REDUCED VSBY AND
LOW STRATUS...HOWEVER CONFIDENCE IS HIGHER FOR FOG AND NOT AS HIGH
FOR THE STRATUS. THIS WILL HAVE TO BE MONITORED CLOSELY. MODEL
CROSS SECTIONS AND BUFR MODEL SOUNDINGS ALL SUPPORT PRONOUNCED
NEAR SURFACE INVERSION - WHICH WOULD FAVOR SOME STRATUS FORMATION.


&&

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

$$

SYNOPSIS...LOTHAMER
SHORT TERM...LEWIS
LONG TERM...SKIPPER
AVIATION...LEWIS


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