Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 241702
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
102 PM EDT SUN AUG 24 2014

.SYNOPSIS...
ISSUED AT 349 AM EDT SUN AUG 24 2014

REGION WILL BE SANDWICHED BETWEEN HOT...HUMID AND AT TIMES STORMY
CONDITIONS TO THE WEST AND SOMEWHAT COOLER AND LESS HUMID
CONDITIONS TO THE EAST. THIS WILL ALLOW FOR DRY CONDITIONS THROUGH
TONIGHT. HIGHS TODAY WILL CLIMB INTO THE 80S WITH LOWS TONIGHT
DROPPING BACK INTO THE MID TO UPPER 60S.

&&

.UPDATE...
ISSUED AT 1245 PM EDT SUN AUG 24 2014

A HIGHLY SHEARED VORT MAX WILL CONTINUE TO TOP MID LEVEL RIDGING
ACROSS THE WESTERN GREAT LAKES REGION THIS AFTERNOON. A FEW
SHOWERS TRIED TO FORM EARLIER THIS MORNING IN ADVANCE OF THIS
FEATURE...BUT EXPECTING THAT SHARED NATURE OF VORT WILL KEEP
FORCING WEAK ENOUGH TO LIMIT ANY ISOLATED SHOWER DEVELOPMENT THIS
AFTERNOON ACROSS THE NORTH. INFLUX OF DRIER EASTERLY LOW LEVEL
FLOW SHOULD ACT TO CONTRACT LOW LEVEL THETAE RIDGE THIS AFTERNOON
AND CONFINE IT MAINLY TO THE WESTERN HALF OR WESTERN TWO THIRDS
OF THE AREA. FORCING WILL REMAIN QUITE WEAK THROUGH THE DAY AND
WILL CONTINUE TO KEEP DRY FORECAST GOING...ALTHOUGH LATEST VISIBLE
SATELLITE TRENDS SUGGEST A ZONE OF WEAK LOW LEVEL CONVERGENCE
SETTING UP FROM NEAR ELKHART TO NORTH OF KFWA THAT COULD
EVENTUALLY YIELD A STRAY SHOWER OR STORM. TEMPERATURES APPEAR
REASONABLE...WITH AT LEAST SOME INSOLATION EXPECTED THIS AFTERNOON
EVEN ACROSS AREAS WHERE STRATUS LINGERS AT MIDDAY. UPDATED ZONES
HAVE BEEN SENT TO REFRESH MORNING WORDING.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 349 AM EDT SUN AUG 24 2014

MUCH MORE TRANQUIL SHORT TERM PERIOD APPEARS TO BE IN STORE FOR THE
NEXT 24 TO 36 HOURS AS DRIER EASTERLY FLOW CONTINUE TO PUSH THE MAIN
FOCUS FOR SHOWERS AND THUNDERSTORMS PRETTY MUCH OUT OF THE AREA.

FOG AND STRATUS HAVE BEEN MUCH SLOWER TO DEVELOP TONIGHT...LIKELY
LENDING TO SOMEWHAT DRIER AIRMASS AND 5 TO 8 KT WIND FROM THE EAST.
A FEW LOCATIONS HAVE BEGUN TO DROP INTO THE 4 TO 5 MILE RANGE AND
WOULD EXPECTED A BIT MORE OF A DROP WITH TIME. HAVE DECIDED TO ADD
PATCHY FOG THROUGH 12Z BUT LEAVE ANY DENSE MENTION OUT.

DURING THE DAY PARTLY CLOUDY SKIES (MAINLY IN THE FORM OF LINGERING
MID AND HIGH CLOUDS) SHOULD GIVE WAY TO INCREASING AMOUNTS OF SUN
INTO EARLY AFTERNOON BEFORE CU START TO FORM ACROSS THE AREA.
GREATEST CONCENTRATION WILL LIKELY BE IN FAR SW AREAS CLOSER TO
BETTER MOISTURE. IF TEMPS JUMP INTO THE 80S AS PROGGED...SURFACE
BASED CAPE IN THE 500 TO 750 J/KG RANGE WILL BE IN PLACE IN THESE
SAME AREAS WITH LITTLE OR NO INSTABILITY EAST OF US 31. WHILE A
STRAY SHOWER OR STORM CANNOT BE RULED OUT THIS AFTERNOON FAR
WEST...NO CLEAR TRIGGER OR SIGNAL THAT SOMETHING COULD DEVELOP. HAVE
FOLLOWED SUIT WITH MOST OTHER OFFICES AND REMOVED SLGT CHC OF STORMS
THIS AFTERNOON.

TONIGHT THERMAL RIDGE AXIS WILL BEGIN TO SHIFT BACK SLOWLY TO THE
EAST WITH LOWS IN THE MID TO UPPER 60S...WHICH IS STILL WARM FOR
THIS TIME OF YEAR...BUT A BIT MORE COMFORTABLE COMPARED TO PAST
SEVERAL NIGHTS.

&&

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 349 AM EDT SUN AUG 24 2014

UPR LEVEL RIDGE OVER THE OH VALLEY SHOULD RESULT IN DRY CONDITIONS
WITH CONTD ABOVE NORMAL TEMPS MONDAY. LESS CLOUDINESS THAN PREVIOUS
DAYS EXPECTED TO ALLOW FOR HIGHS IN THE U80S/L90S. LOW LEVEL
SOUTHERLY FLOW OVER THE AREA AS SE CANADA SFC HIGH MOVES TO THE MID
ATLANTIC COAST SHOULD ADVECT L70S DWPTS BACK INTO THE AREA RESULTING
IN HEAT INDEX READINGS MONDAY 5-10DEGREES HIGHER THAN ACTUAL TEMPS.

A CDFNT IS EXPECTED TO MOVE SE ACROSS THE UPR GRTLKS MONDAY
NIGHT...PSBLY CAUSING SOME TSTMS TO REACH THE NRN PORTION OF OUR
CWA. THE FRONT IS EXPECTED TO BECOME E-W ORIENTED AND SAG SLOWLY
SOUTH INTO VERY UNSTABLE AIRMASS OVER OUR AREA TUE-TUE NGT. RATHER
WK DEEP LAYER SHEAR SUGGESTS LIMITED SVR RISK DESPITE THE
INSTABILITY IN PLACE. HEAVY RAINFALL COULD BE A PROBLEM AS PWATS
AROUND 2" POOL ALONG THE FRONT WITH SMALL MBE VECTORS SUGGESTING
TRAINING/BACKBUILDING CELLS A POSSIBILITY.

FOR THE EXTENDED FCST... LARGE DIFFERENCES IN MODELS WITH ECMWF/GEM
CONTG TO CUT-OFF LOW IN OVER WRN U.S. BY WED WHILE GFS IS MORE
PROGRESSIVE MOVG THE WRN TROF EAST INTO THE PLAINS. GFS SOLUTIONS
SUGGESTS A GOOD CHC OF TSTMS MID-WEEK WITH DRY CONDITIONS BY THE
WEEKEND... WHILE SLOWER ECMWF/GFS OFFER UP THE OPPOSITE SCENARIO.
GIVEN LACK OF MODEL AGREEMENT AND POOR MODEL RUN-RUN CONSISTENCY...
STAYED CLOSE TO PREVIOUS FCST WITH A CHC OF TSTMS THROUGH THIS
PERIOD AND DOWNWARD TREND IN TEMPS BACK TO NEAR NORMAL.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1245 PM EDT SUN AUG 24 2014

LIGHT EASTERLY FLOW AT 10 KNOT OR LESS TO CONTINUE THROUGH THE
REMAINDER OF THE AFTERNOON. WEAK GRADIENT WILL PERSIST INTO
TONIGHT AS EASTERN GREAT LAKES HIGH PRESSURE SHIFTS SOUTHWARD INTO
THE MID ATLANTIC STATES. SOME VEERING OF LOW LEVEL WINDS LATER
TONIGHT WILL ALLOW FOR MOISTURE TO LIFT BACK NORTHWARD...AND WITH
WEAK GRADIENT PERSISTING SOME PATCHY FOG MAY REDEVELOP TONIGHT AND
SEE NO REASON TO DEVIATE FROM TEMPO MVFR CONDITIONS IN THE 09Z-13Z
TIMEFRAME. MID/UPPER LEVEL RIDGING TO REMAIN IN PLACE ACROSS THE
AREA MONDAY...WITH OVERALL SUPPORT FOR SYNOPTIC SCALE SUBSIDENCE.
VERY UNSTABLE CONDITIONS TO DEVELOP MONDAY AFTERNOON...BUT WITH
LACK OF ANY CLEAR TRIGGER AND WEAKLY SUBSIDENT REGIME
MONDAY...WILL CONTINUE TO MAINTAIN A DRY FORECAST THROUGH THE END
OF THIS FORECAST VALID PERIOD.

&&

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

$$

UPDATE...MARSILI
SYNOPSIS...FISHER
SHORT TERM...FISHER
LONG TERM...JT
AVIATION...MARSILI


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