Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 270539
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
139 AM EDT THU AUG 27 2015

.SYNOPSIS...
ISSUED AT 759 PM EDT WED AUG 26 2015

HIGH PRESSURE WILL MOVE INTO THE REGION OVERNIGHT AND BRING
CLEARING SKIES. AREAS OF FOG ARE EXPECTED TO DEVELOP BY DAYBREAK.
LOWS TONIGHT WILL BE ON THE COOL SIDE...PRIMARILY IN THE LOWER
50S. HIGHS ON THURSDAY WILL PUSH INTO THE LOWER 70S UNDER MOSTLY
SUNNY SKIES.

&&

.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
LITTLE 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 NORTHEASTWARD. 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 CROSS 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 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 133 AM EDT THU AUG 27 2015

CLOUD COVER HAS DISSIPATED AROUND KSBN AND PUSHED MORE TOWARDS THE
LAKE SHORE AREAS. VFR CIGS WERE PERSISTING AT KFWA IN THICKER AREA
OF CLOUDS. IF CLOUDS HOLD...FOG MAY BE LESS OF AN ISSUE AT KFWA
BUT WILL HOLD WITH PAST TAFS AND MONITOR TRENDS FOR NEXT COUPLE OF
HOURS. AT KSBN...CROSS OVER TEMP OF 54 HAS BEEN MET...BUT SOME
MIXING OUT HAS OCCURRED WITH DEWPTS STILL FALLING. A FEW SITES
HAVE SHOWN SHALLOW FOG WITH HIGHLY VARIABLE VSBYS...MAKING THE
TAFS EVEN MORE CHALLENGING AS EVEN THE TEMPO REQUIREMENTS MAY NOT
BE FULLY MET. AS WITH KFWA WILL WATCH TRENDS AND AMEND AS NEEDED.

BY MID MORNING...ANY CONCERNS WILL BE GONE AS SUBSIDENCE TAKES
FULL HOLD AND LITTLE MORE THAN A FEW CU CAN BE EXPECTED WITH LIGHT
WINDS.

&&

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

$$

SYNOPSIS...MURPHY
SHORT TERM...LEWIS
LONG TERM...SKIPPER
AVIATION...FISHER


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