558
FXUS63 KIWX 181657
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
1257 PM EDT TUE SEP 18 2018
SYNOPSIS
ISSUED AT 332 AM EDT TUE SEP 18 2018
WARM CONDITIONS CAN BE EXPECTED THIS WEEK. HIGHS WILL GENERALLY
BE IN THE LOWER TO MIDDLE 80S EACH DAY, EXCEPT A BIT COOLER NEAR
LAKE MICHIGAN. THERE IS A SLIGHT CHANCE FOR THUNDERSTORMS THIS
AFTERNOON, THEN A CHANCE FOR SHOWERS AND THUNDERSTORMS ON
WEDNESDAY, AND AGAIN LATE THURSDAY NIGHT INTO FRIDAY. TEMPERATURES
WILL TREND COOLER, MORE SEASONABLE THIS WEEKEND INTO EARLY NEXT
WEEK.
SHORT TERM
(TODAY AND TONIGHT)
ISSUED AT 322 AM EDT TUE SEP 18 2018
LIKE A BROKEN RECORD, FOG WAS BEEN SEEN IN AREAS FOR YET ANOTHER
MORNING. BY IN LARGE IT IS NOT CAUSING MANY IMPACTS BUT POCKETS OF
BRIEF DENSE FOG HAVE BEEN NOTED. WILL MONITOR TRENDS BUT NOT
EXPECTED TO BE WIDESPREAD ENOUGH TO WARRANT MUCH MORE THAN A SPS
AT THIS POINT. UPSTREAM CONVECTION ACROSS MINNESOTA WILL BE THE
MAIN FOCUS INTO TODAY. SERIES OF OUTFLOW BOUNDARIES, PRE- FRONTAL
TROUGH AND FRONTAL BOUNDARY WILL ALL DRIFT SOUTHEAST INTO THE AREA
FOR MUCH OF THIS PERIOD AND INTO THE LONG TERM. NAMNEST APPEARS
TO HAVE BEST HANDLING OF CURRENT SITUATION WITH IT AND TO A LESSER
EXTENT HRRR/ARW SHOWING DECAYING STORMS MOVING TOWARDS THE AREA
THIS MORNING. HAVE BACKED OFF POPS THROUGH THE MORNING WITH TIMING
OF UPSTREAM CONVECTION AND LIKELY WEAKENING STATE ALL EXPECTED TO
REDUCE ANY CHANCES FOR MEASURABLE. LEFT TOKEN SLGT CHC POPS THIS
AFTERNOON WITH RESIDUAL BOUNDARIES AROUND. HIGHS TODAY WILL VARY
FROM NORTH TO SOUTH WITH WARMEST READINGS IN THE SOUTH (MID- UPR
80S VS UPR 70S-LOW 80S).
BRIEF LULL MAY TAKE PLACE IN PRECIP CHANCES BUT MAIN FRONTAL
BOUNDARY WILL BE IN THE AREA BY LATER TONIGHT INTO THE LONG TERMS
PERIOD TO BRING NON-ZERO CHANCES FOR A POP UP SHOWER/STORM.
THERMAL PROFILES DON'T CHANGE A WHOLE LOT WITH MAIN FORCING AND
COLDEST AIR REMAINING WELL NW OF THE AREA. LOWS IN THE 60S ARE
EXPECTED. MODELS HAVE BEEN HINTING AT SLIGHTLY BETTER CHANCE FOR
SOME FOG TONIGHT BUT WON'T ADD AT THIS POINT.
LONG TERM
(WEDNESDAY THROUGH MONDAY)
ISSUED AT 322 AM EDT TUE SEP 18 2018
FRONTAL BOUNDARY WILL RESIDE NEAR/SOUTH OF THE AREA DURING THE DAY
WEDNESDAY WITH YET ANOTHER COMPLEX OF STORMS EXPECTED UPSTREAM
TUESDAY NIGHT WHICH MAY MOVE INTO NW AREAS WEDS MORNING. LEFTOVER
OUTFLOW BOUNDARY MAY PROVIDE FOCUS FOR ADDITIONAL CONVECTION WEDS
AFTERNOON BEFORE MAIN SYNOPTIC FRONT STARTS TO PUSH BACK NORTH WEDS
NIGHT INTO THURSDAY WITH YET ANOTHER COMPLEX ALONG IT. MODELS VARY
GREATLY ON IMPACTS GIVEN WHAT WILL BE A CHALLENGING ENVIRONMENT.
WILL MAINTAIN MID RANGE CHC POPS UNTIL FRONT PUSHES BACK NORTH ON
THURSDAY. LOCATIONS SOUTH OF THE FRONT WILL BREEZY CONDITIONS AND
HIGHS WELL INTO THE 80S, WITH 850 MB TEMPS PUSHING 20 C SUGGESTING A
FEW SPOTS COULD APPROACH/EXCEED 90.
STRONGER COLD FRONT AND ASSOCIATED UPPER LEVEL TROUGH WILL FINALLY
SWING THROUGH DURING THE DAY FRIDAY WITH CHANCE OF SHOWERS AND
STORMS ALONG IT. COVERAGE SOMEWHAT QUESTIONABLE STILL WITH BEST
DYNAMICS REMAINING WELL NORTH BUT SHOULD STILL BE ENOUGH FOR MID TO
HIGH CHC POPS. MORE SEASONABLE AIR WILL ARRIVE BEHIND THE FRONT INTO
THE WEEKEND AND EARLY NEXT WEEK WITH HIGHS IN THE 60S TO LOWER
70S AND LOWS IN THE 50S.
AVIATION
(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1256 PM EDT TUE SEP 18 2018
CONVECTIVE ACTIVITY LIKELY TO REMAIN SUPPRESSED AMID OUTFLOW
DOMINANT ENVIRONMENT AND NOMINAL INSTABILITY ACROSS NORTHERN
INDIANA. CONCERN REMAINS FOR BRIEF VISIBILITY REDUCTION NEAR
SUNRISE IN SHALLOW/PATCHY FOG, THOUGH OVERALL ANY REDUCTIONS
SHOULD BE MINOR/BRIEF. LATER FORECAST ISSUANCES TO FURTHER ASSESS
THUNDERSTORM POTENTIAL LATER WEDNESDAY AFTERNOON.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
SYNOPSIS...FISHER
SHORT TERM...FISHER
LONG TERM...FISHER
AVIATION...MURPHY
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