387
FXUS63 KIWX 091041
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
641 AM EDT SUN AUG 9 2020
SYNOPSIS
ISSUED AT 307 AM EDT SUN AUG 9 2020
DRY CONDITIONS TODAY INTO THIS EVENING WILL GIVE WAY TO CHANCES
FOR SHOWERS AND THUNDERSTORMS LATER TONIGHT THROUGH MONDAY NIGHT.
BECOMING HUMID OTHERWISE WITH HIGHS BETWEEN 85 AND 90 DEGREES.
MAINLY DRY CONDITIONS AND SEASONABLE TEMPERATURES INTO TUESDAY
AND WEDNESDAY WILL BE FOLLOWED BY PERIODIC CHANCES FOR SHOWERS AND
THUNDERSTORMS THURSDAY AND FRIDAY.
SHORT TERM
(TODAY THROUGH MONDAY NIGHT)
ISSUED AT 307 AM EDT SUN AUG 9 2020
RIDGING ALOFT WILL ALLOW FOR ANOTHER DRY/MOSTLY SUNNY DAY WITH
CONVECTION FOCUSED NEAR A SFC WARM FRONT IN THE MID MS VALLEY,
AND UP ACROSS THE UPPER MIDWEST/NORTHERN LAKES ON SOUTHERN FRINGE
OF WESTERLIES. LOW LEVEL SOUTHWEST FLOW WILL ALLOW FOR AN UPTICK
IN TEMPS AND HUMIDITY OTHERWISE WITH HIGHS INTO THE UPPER 80S
FOLD OVER OF DEEPER UPSTREAM MOISTURE WILL ALLOW SHOWER/STORM
CHANCES TO ENTER THE FORECAST LATER TONIGHT THROUGH MONDAY EVENING.
FOCUS INITIALLY WILL RELY ON A REMNANT OUTFLOW/MCV TO SPILL
SOUTHEAST INTO THE AREA FROM THE UPPER MIDWEST INTO SW MI AND
WESTERN IN. POOR DIURNAL TIMING AND OUTRUN FROM BETTER SUPPORT
SUPPORTS A WEAKENING TREND AND LOW-MID CHANCE POPS MONDAY
MORNING/EARLY AFTERNOON. IF THIS OUTFLOW AND POSSIBLE MCV IS
SLOWER, ALLOWING FOR GREATER DIURNAL HEATING, THERE COULD BE AN
UPTICK IN CONVECTION MID-LATE AFTN INTO NE IN/SC MI/NW OH.
RELIANCE ON THESE SMALLER SCALE (CONVECTIVELY AIDED) FEATURES
MAKES FOR A LOW CONFIDENCE FCST AND NOTHING MORE THAN A LOW-MID
CHANCE POP.
A COLD FRONT WILL TRAIL A NORTHERN LAKES SHORTWAVE INTO THE AREA
MONDAY NIGHT WITH SLIGHTLY BETTER PROSPECTS FOR SHOWERS AND
STORMS, ESPECIALLY WESTERN ZONES LATE EVENING/EARLY OVERNIGHT AS
AMPLE MOISTURE AND THE POTENTIAL FOR ANOTHER CONVECTIVELY AIDED
VORT ACCOMPANIES THE SOUTHWARD SAGGING FRONT.
LONG TERM
(TUESDAY THROUGH SATURDAY)
ISSUED AT 307 AM EDT SUN AUG 9 2020
SLOW MOVING CONVECTIVE COMPLEXES AND A LINGERING INSTABILITY
GRADIENT WILL IMPACT THE MID MS/OH VALLEYS MID-LATE WEEK, WHILE
RIDGING ALOFT AND AT THE SFC BUILDS OVER THE GREAT LAKES AND SE
CANADA. THIS REGIME SHOULD BE ENOUGH TO KEEP THE BULK OF
SHOWER/STORM ACTIVITY SSW OF THE AREA TUESDAY INTO WEDNESDAY, THOUGH
SOME LOWER POPS REMAIN OVER SOUTHERN ZONES GIVEN CLOSE PROXIMITY
TO THE LINGERING BOUNDARY. RETAINED BROADBRUSH LOW-MID CHANCE POPS
AREA-WIDE (HIGHEST PM) THEREAFTER AS CONFIDENCE WANES REGARDING
POSITIONING OF THE BOUNDARY AND TRACK/TIMING OF A SLOW MOVING MID
MS TROUGH. SEASONAL TEMPS OTHERWISE WITH HIGHS GENERALLY LOW-MID
80S.
AVIATION
(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 640 AM EDT SUN AUG 9 2020
VFR CONDITIONS THROUGH THE FORECAST PERIOD. EASTERN FLANK OF
HIGHER SURFACE DEWPOINTS/DIURNAL INSTABILITY POOL TO PROGRESS
GRADUALLY EASTWARD FROM MID MISSISSIPPI VALLEY/UPPER MIDWEST INTO
NORTHERN INDIANA THROUGH THE FORECAST PERIOD. FOCUS FOR DEEP
MOIST CONVECTION HOWEVER, APPEARS TIED TO NORTHERN STREAM
SHORTWAVE WELL UPSTREAM WITH POSSIBLE DECAYING MESOSCALE
CONVECTIVE SYSTEM ARRIVAL LATE IN THE FORECAST PERIOD INTO KSBN.
CHANCES APPEAR QUITE LOW AT THIS TIME AND OPT TO EXCLUDE MENTION.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
SYNOPSIS...STEINWEDEL
SHORT TERM...STEINWEDEL
LONG TERM...STEINWEDEL
AVIATION...MURPHY
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