Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 230546
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
146 AM EDT THU OCT 23 2014

.SYNOPSIS...
ISSUED AT 351 PM EDT WED OCT 22 2014

HIGH PRESSURE WILL BE ACROSS THE REGION TONIGHT INTO THURSDAY.
SKIES WILL GENERALLY BE CLEAR OVER WESTERN PORTIONS OF
MICHIGAN AND INDIANA. CLOUDS OVER EASTERN AREAS WILL SLOWLY ERODE
THIS EVENING LEAVING BEHIND PARTLY CLOUDY TO MOSTLY CLEAR SKIES.
LOWS TONIGHT WILL DROP INTO THE LOWER AND MIDDLE 30S. HIGHS ON
THURSDAY WILL REACH THE MIDDLE AND UPPER 50S.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 351 PM EDT WED OCT 22 2014

DESPITE HIGH PRESSURE OVER THE AREA AND RELATIVELY QUIET WEATHER
CONDITIONS...A FEW WEATHER ISSUES DO PERSIST WITH RESPECT TO CLOUD
COVER AND TEMPERATURES TONIGHT INTO THURSDAY MORNING.

VISIBLE SATELLITE IMAGERY TELLS THE STORY WITH STRATUS DECK STILL
LINGERING OVER EASTERN HALF OF FORECAST AREA AS OF 18Z. SOME SLOW
EROSION HAS BEEN NOTED OVER WESTERN EDGE AND SOME CLEARING
APPROACHING FROM NORTHEAST PER LIGHT NORTHEAST LOW LEVEL WINDS.
MODELS REMAIN RATHER PERSISTENT THAT AREA OF STRATUS WILL CONTINUE
TO THIN AND DISSIPATE THIS EVENING PER HRRR RH AND TOTAL CLOUD COVER
PLOTS ALONG WITH LATEST RAP13 RH FIELDS IN THE 900-850MB LAYERS.
CONCERN THOUGH LIES WITH LIGHT NORTHERLY FLOW EXPECTED TONIGHT WITH
A RATHER STOUT LOW LEVEL INVERSION. 925-850MB THERMAL RIDGE REMAINS
OVER EASTERN IL AND WESTERN IN THROUGH THE NIGHT ALONG WITH 500MB
RIDGE AXIS. TYPICALLY STRATUS EROSION DOES NOT OCCUR UNTIL PASSAGE
OF THESE FEATURES. HOWEVER...SOUNDINGS SHOW A VERY DRY AIRMASS
SITTING ATOP VERY THIN LAYER OF CLOUDS AND INCREASING SUBSIDENCE
LATE THIS AFTERNOON AND EVENING MAY CONTINUE TO ERODE THE CLOUD DECK
AS ADVERTISED. HAVE CONTINUED TO SLOW THE EROSION IN THE SKY COVER
GRIDS BUT DID KEEP THE OPTIMISTIC ATTITUDE IN ORDER TO MATCH
SURROUNDING SITES FOR A MORE CONSISTENT LOOKING FORECAST.

TEMPERATURES TO BE IMPACTED SIGNIFICANTLY IF THESE CLOUDS DO HOLD ON
THROUGH THE NIGHT. FOR NOW STAYED WITH PERSISTENCE AND OPTIMISTIC
FORECAST WITH LOWS DROPPING INTO THE LOWER AND MID 30S. PREVIOUS
GUIDANCE HAS BEEN THE BEST PERFORMING GUIDANCE OVER THE LAST
WEEK...15 DAYS AND 30 DAYS SO WILL RIDE WITH THAT. FORECAST
SOUNDINGS ALSO SHOW A VERY MOIST SHALLOW LAYER NEAR SURFACE UNDER
STRONG INVERSION WITH VERY DRY AIR ALOFT AND LIGHT WINDS THROUGH A
DEEP COLUMN. THIS USUALLY AN IDEAL SETUP FOR FOG DEVELOPMENT SO
ADDED PATCHY FOG TO GRIDS.

EXPECT THURSDAY TO REMAIN DRY AHEAD OF NEXT WEAK SHORT WAVE WITH
INCREASING HIGH CLOUDS IN THE WEST DURING THE AFTERNOON. RAWBLEND
GUIDANCE PERFORMING BEST WITH MID TO UPPER 50S EXPECTED FOR HIGHS.

&&

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 351 PM EDT WED OCT 22 2014

AN UPPER LEVEL TROF WILL MOVE ACROSS THE AREA THURSDAY NIGHT. UPPER
LEVEL SUPPORT WAS LAGGING BEHIND LOWER LEVELS...WITH QUESTIONABLE
SATURATION THROUGH THE CLOUD LAYER. REFINED THE TIMING OF THE CHANCE
FOR SHOWERS GIVEN THE LATEST MODEL EXPECTATIONS. VERY LITTLE
RAINFALL IS EXPECTED WITH THIS SYSTEM GIVEN LIMITED  SATURATION...
WEAK LIFT AND LACK OF MOISTURE. A BACK DOOR TYPE OF FRONT SHOULD
MOVE ACROSS THE AREA THIS WEEKEND AND BECOME STATIONARY NEAR OR OVER
THE FORECAST AREA. KEPT THE FORECAST DRY GIVEN LIMITED MOISTURE AND
LIMITED LOW LEVEL FORCING ALONG THE FRONT. LOWERED HIGHS SUNDAY INTO
THE 50S NORTHEAST OF THE FRONT. THERE WAS MUCH UNCERTAINTY WITH THE
TIMING AND STRENGTH OF THE NEXT SYSTEM. FAVOR THE GFS WHICH HAS
BETTER RUN TO RUN CONSISTENCY THAN THE ECMWF WITH THE BEST CHANCE
FOR RAIN ABOUT TUESDAY.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 141 AM EDT THU OCT 23 2014

STRATOCU DECK HAS DISSIPATED ACROSS THE AREA. THE CLEARING
COMBINED WITH MOIST CONDITIONS AND LIGHT WINDS WILL CONTINUE TO
SET THE STAGE FOR FOG DEVELOPMENT...ESPECIALLY AROND KFWA WHICH
HASN`T HAD A CHANCE TO MIX OUT ALL THE MOISTURE FROM RECENT RAINS
DUE TO CLOUDS. HAVE HELD WITH MVFR FOR NOW AT BOTH SITES...BUT
CAN`T RULE OUT SOME WIDELY VARIABLE VSBYS AT KFWA THAT COULD
IMPINGE ON IFR. WHILE THIS MAY OCCUR...ANY FOG SHOULD BE SHALLOW.

SKIES WILL CLEAR WITH VFR CONDITIONS THE REMAINDER OF THE PERIOD.
THE NEXT SYSTEM WILL BRING INCREASING HIGH CLOUDS TOWARDS
00Z/FRI WITH A CHANCE FOR A FEW SPRINKLES OR A LIGHT SHOWER AT
KSBN. NOT WORTHY OF ANY MENTION AT THIS POINT.

&&

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

$$

SYNOPSIS...FISHER
SHORT TERM...LASHLEY
LONG TERM...SKIPPER
AVIATION...FISHER


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