Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 211959
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
359 PM EDT TUE OCT 21 2014

.SYNOPSIS...
ISSUED AT 351 AM EDT TUE OCT 21 2014

LOW PRESSURE WILL DRIFT SLOWLY EAST OUT OF THE GREAT LAKES INTO
THE CAROLINAS BY WEDNESDAY. SKIES WILL CLEAR ACROSS WESTERN AREAS
BY LATE AFTERNOON WITH MOSTLY CLOUDY SKIES HOLDING UNTIL TONIGHT
IN THE EAST. HIGHS WILL CLIMB INTO THE 50S THIS AFTERNOON WITH
LOWS TONIGHT INTO THE LOWER TO MIDDLE 30S.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 357 PM EDT TUE OCT 21 2014

SECONDARY PUSH OF CAA NOW WELL UNDERWAY WITH THE PASSAGE OF THIS
MORNING`S SHORTWAVE AND ASSOCIATED SURFACE PRESSURE TROUGH. REGIONAL
LOW LEVEL WINDS HAVE GRADUALLY VEERED TO A MORE NNE DIRECTION...
ADVECTING COOL/DRY AIR INTO THE AREA AND LEADING TO AN UNFAVORABLE
TRAJECTORY FOR LAKE ENHANCEMENT IN OUR CWA. MIDLEVEL HEIGHTS ARE
ALSO BEGINNING TO RISE AS HIGH AMPLITUDE/SHORT WAVELENGTH RIDGE
FOLDS INTO THE GREAT LAKES. ASSOCIATED AVA WILL GENERATE STRONG
SUBSIDENCE AND SUPPORT THE MAINTENANCE OF A DECENT SURFACE
ANTICYCLONE OVER THE REGION TONIGHT THROUGH TOMORROW. LIGHT RAIN
SHOWERS HAVE GRADUALLY DISSIPATED THIS AFTERNOON AS EXPECTED AND DRY
CONDITIONS SHOULD PERSIST THROUGH TOMORROW. ONLY POSSIBLE EXCEPTION
MAY BE SOME LAKE EFFECT SHOWERS OFF OF HURON IN OUR FAR EASTERN
ZONES BUT CHANCES APPEAR VERY SLIM AND WILL MAINTAIN DRY FORECAST.
CAA HAS KEPT A LID ON AFTERNOON TEMPS AND EXPECT OVERNIGHT LOWS TO
TAKE A SIMILAR DIP. EXPECT GRADUAL CLEARING IN OUR WESTERN
COUNTIES...WITH A LIGHT NE WIND ALLOWING OVERNIGHT LOWS TO DROP INTO
THE LOW TO MID 30S. CLOUDS LINGER A BIT LONGER IN THE EAST AND WILL
HOLD WITH TEMPS IN THE MID TO UPPER 30S THERE. GROWING SEASON HAS
ENDED ACROSS THE CWA SO NO HEADLINES WARRANTED. STRATOCU WILL
GRADUALLY DISSIPATE IN EVEN OUR EASTERN COUNTIES BY TOMORROW
AFTERNOON AND EXPECT SOME MODERATION OF THERMAL PROFILES DESPITE
WEAK NORTHEAST FLOW. INHERITED FORECAST OF MID 50S IS IN LINE WITH
LATEST GUIDANCE AND NO MAJOR CHANGES NECESSARY.

&&

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 357 PM EDT TUE OCT 21 2014

A WEAKENING UPPER LEVEL SYSTEM WILL MOVE ACROSS THE AREA LATE
THURSDAY INTO THURSDAY NIGHT. UPPER LEVEL SUPPORT/DIFFERENTIAL
VORTICITY ADVECTION IN THE 500/300 MB LAYER WILL BE WANING AS THE
UPPER LEVEL TROF MOVES ACROSS THE AREA IN LIGHT OF THE BUILDING
UPPER LEVEL RIDGE IN THE SYNOPTIC SCALE. MADE SOME MINOR ADJUSTMENTS
TO THE ONGOING GRIDS/FORECAST WITH A SLIGHT CHANCE FOR SHOWERS OVER
WEST AREAS GIVEN THE LACK OF DEEP SATURATION AND WEAK LIFT PER 305K
ISENTROPIC SURFACE. VERY LITTLE RAINFALL IS EXPECTED. TEMPERATURES
SHOULD WARM TO MUCH ABOVE NORMAL BY EARLY NEXT WEEK. GIVEN ECMWF AND
GFS 850 MB TEMPS 13C TO 16C...HIGHS SHOULD BE ABLE TO CLIMB TO AT
LEAST AROUND 70 DEGREES WITH LITTLE IF ANY RAIN EXPECTED THROUGH THE
DAY MONDAY.  THE ECMWF AND GFS HAVE COME INTO BETTER AGREEMENT WITH
THE TIMING OF THE FRONT TUESDAY. TEMPERATURES SHOULD BE MILD MONDAY
NIGHT WITH A CHANCE FOR RAIN MONDAY NIGHT AND TUESDAY AS THE FRONT
MOVES INTO THE AREA. GUT FEELING IS RAIN CHANCES MAY NEED TO BE
RAISED TUESDAY GIVEN AVAILABLE MOISTURE...FRONTAL LIFT AND UPPER
LEVEL JET SUPPORT.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 126 PM EDT TUE OCT 21 2014

LOW LEVEL CONVERGENCE AND THETA-E FLUX FROM THE GREAT LAKES IS
SUPPORTING HIGH END MVFR CEILINGS ACROSS THE AREA AT PRESS TIME.
EXPECT THIS STUBBORN STRATOCU DECK WILL GRADUALLY ERODE BY LATER
THIS EVENING BUT EXACT TIMING OF TRANSITION TO VFR CONDITIONS
REMAINS SOMEWHAT UNCERTAIN. SATELLITE IMAGERY AND UPSTREAM OBS
STILL SHOW A LARGE AREA OF 3 KFT CEILINGS YET TO GO AND LATEST
MODEL GUIDANCE SUGGEST CLOUDS WILL NOT SCATTER UNTIL AT LEAST
21-00Z. HAVE THEREFORE PUSHED BACK THE TRANSITION TO VFR CATEGORY
BY A FEW HOURS. FOR TONIGHT AND TOMORROW...MUCH HIGHER CONFIDENCE
THAT VFR CONDITIONS WILL PREVAIL AS STRONG HIGH PRESSURE AND
SUBSIDENCE BUILD OVER THE REGION.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 5 AM EDT WEDNESDAY FOR LMZ043-046.

&&

$$

SYNOPSIS...FISHER/SKIPPER
SHORT TERM...AGD
LONG TERM...SKIPPER
AVIATION...AGD


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