Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 011953
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
353 PM EDT FRI AUG 1 2014

.SYNOPSIS...
ISSUED AT 329 AM EDT THU AUG 1 2014

SCATTERED...MAINLY AFTERNOON AND EARLY EVENING...SHOWERS AND
THUNDERSTORMS ARE EXPECTED THROUGH SATURDAY AS AN UPPER LEVEL
TROUGH MOVES ACROSS THE REGION. DRY CONDITIONS ARE EXPECTED ON
SUNDAY AS THE UPPER LEVEL SYSTEM MOVES OFF TO THE EAST. LOWS
TONIGHT ARE EXPECTED TO BE IN THE UPPER 50S AND LOWER 60S... WITH
HIGHS SATURDAY MAINLY IN THE LOWER 80S... EXCEPT COOLER NEAR LAKE
MICHIGAN.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 346 PM EDT FRI AUG 1 2014

SHRTWV MOVG THROUGH BASE OF TROF INTO NW INDIANA PROVIDED FORCING TO
KICK OFF SCT TSTMS ACROSS NWRN PORTION OF THE CWA EARLY THIS AFTN.
INITIAL STORMS HAVE BECOME OUTFLOW DOMINANT AND GENERALLY SHOWING
WKNG TREND FOR PAST HOUR... BUT ADDITIONAL STORMS EXPECTED TO
DEVELOP ALONG OUTFLOW BOUNDARY WHICH WAS PUSHING INTO SERN 1/2 OF
THE AREA WHERE MODERATE INSTABILITY WAS IN PLACE. WK SHEAR AND
LIGHT WIND REGIME SHOULD KEEP STORMS PULSE TYPE AND SUB-SEVERE...
BUT STEEP LAPSE RATES MAY RESULT IN SOME SMALL HAIL... AND SLOW
MOVEMENT OF STORMS WITH SOME UPWIND PROPAGATION SUGGESTS LOCALLY
HEAVY RAINFALL STILL PSBL LATE THIS AFTN. STORMS SHOULD GRDLY
WEAKEN WITH LOSS OF HEATING OVERNIGHT. MODERATE DIURNAL
INSTABILITY EXPECTED TO DEVELOP AGAIN ON SATURDAY WITH TROF
AXIS/COOL POOL ALOFT MOVG THROUGH THE AREA. THIS SHOULD ALLOW SCT
TSTMS TO DEVELOP ONCE AGAIN... WITH HIGHEST POPS SAT AFTN AHEAD OF
THE TROF OVER ERN PORTION OF THE CWA. LITTLE CHANGE IN TEMPS FROM
THE LAST COUPLE DAYS IS EXPECTED THROUGH THE SHORT TERM PERIOD
WITH LOWS TONIGHT IN THE U50S/L60S AND HIGHS SATURDAY IN THE
U70S/L80S. EXCEPTION SHOULD BE NEAR LAKE MICHIGAN SATURDAY WHERE
WK NORTHERLY GRADIENT ENHANCED BY LAKE BREEZE SHOULD DEVELOP IN
WAKE OF TROF PASSAGE.

&&

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 346 PM EDT FRI AUG 1 2014

QUIET START TO THE LONG TERM PERIOD AS MIDLEVEL TROUGH AXIS SHIFTS
SOUTHEAST OF THE AREA AND SHORTWAVE RIDGING LEADS TO A BRIEF PERIOD
OF DRY/SUBSIDENT CONDITIONS. POSTFRONTAL THERMAL PROFILES NOT ALL
THAT DIFFERENT FROM CURRENT AIRMASS AND EXPECT HIGH TEMPS ONCE AGAIN
NEAR 80F ON SUNDAY AND MONDAY WITH LOWS AROUND 60F.

FORECAST CONFIDENCE HEADING INTO THE MIDDLE AND END OF NEXT WEEK IS
STILL LOW. ANOTHER SHORTWAVE EMBEDDED IN PREVAILING NORTHWEST FLOW
ALOFT WILL SEND A WEAK FRONTAL BOUNDARY ACROSS THE SOUTHERN GREAT
LAKES ON TUESDAY. LITTLE TO NO MOISTURE ADVECTION AND OVERALL MODEST
SYNOPTIC FORCING SUGGEST LOWER END CHANCE POPS WARRANTED AT THIS
TIME. THIS FRONT WILL THEN STALL SOMEWHERE OVER THE OHIO VALLEY AND
POSSIBLY LIFT BACK NORTH AS A WARM FRONT LATER IN THE WEEK. HIGH
DEGREE OF RUN-TO-RUN AND MODEL-TO-MODEL VARIABILITY REGARDING THE
DETAILS OF THIS EVOLUTION. SUSPECT THERE IS POTENTIAL FOR DECENT
RAIN AT SOME POINT IN THE MIDDLE TO END OF NEXT WEEK BUT DETAILS ARE
FAR FROM CERTAIN AT THIS POINT. WILL MAINTAIN BLANKET LOW CHANCE
POPS FOR NOW...WITH TEMPS NEAR SEASONAL NORMS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 103 PM EDT FRI AUG 1 2014

SCT TSTMS DEVELOPING OVER THE AREA EARLY THIS AFTN AS CONVECTIVE
TEMPS IN THE M-U70S REACHED AHEAD OF APCHG WK SHRTWV. CONVECTION
MOST WIDESPREAD IN DIFFERENTIAL HEATING ZONE SOUTH OF LM AND THESE
SHOULD IMPACT SBN TERMINAL WITH MVFR OR PSBLY IFR CONDITIONS IN TSRA
EARLY IN THE PERIOD. GIVEN WK SHEAR/PULSE NATURE TO STORMS... CONTD
WITH JUST VCTS THIS AFTN AT FWA BUT WILL MONITOR AND MAY NEED TO
INCLUDE A TEMPO TSRA THERE AS WELL. CONVECTION EXPECTED TO
DIMINISH WITH LOSS OF HEATING THIS EVENING. SOME CLEARING LIKELY
ESPECIALLY AT SBN AS UPR LEVEL TROF AXIS MOVES TO NE INDIANA. THIS
SHOULD ALLOW BR TO DEVELOP WITH VSBYS LOWERING TO MVFR AT THE
TERMINALS BY MORNING.

&&

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

$$

SYNOPSIS...JT
SHORT TERM...JT
LONG TERM...AGD/JT
AVIATION...JT


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