219
FXUS63 KIWX 181835
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
235 PM EDT THU JUL 18 2019
SYNOPSIS
ISSUED AT 235 PM EDT THU JUL 18 2019
AREAS OF RAIN AND THUNDERSTORMS THIS AFTERNOON WILL GIVE WAY TO
MAINLY DRY CONDITIONS TONIGHT THROUGH SATURDAY MORNING. CHANCES
FOR SHOWERS AND THUNDERSTORMS RETURN SATURDAY AFTERNOON THROUGH
SUNDAY. HOT AND HUMID OTHERWISE ON FRIDAY AND SATURDAY AS HIGHS
REACH THE 90S AND PEAK AFTERNOON HEAT INDICES REACH TO BETWEEN 100
AND 100 DEGREES. THIS WILL BE FOLLOWED BY A PERIOD OF COOLER AND
LESS HUMID WEATHER CONDITIONS NEXT WEEK.
SHORT TERM
(THIS AFTERNOON THROUGH SATURDAY)
ISSUED AT 235 PM EDT THU JUL 18 2019
CLUSTERS OF SHOWERS/STORMS ASSOCIATED WITH A CONVECTIVELY ENHANCED
WAVE AND WARM ADVECTION SURGE SHOULD EXIT EAST BY LATE THIS
AFTERNOON. AN ISOLATED STRONG STORM WILL BE POSSIBLE. ESTABLISHED
COLD POOL WITH THIS ACTIVITY REALLY PUT ON DAMPER ON HEAT/HUMIDITY
TODAY, MAINLY ALONG/NORTHWEST OF US 24. SOME LATE DAY RECOVER IS
EXPECTED HERE BUT LIKELY NOT ENOUGH FOR HEADLINE LEVEL APPARENT T
VALUES. PUSHED BACK THE EXCESSIVE HEAT WARMING TO FRIDAY ACROSS
NORTHERN ZONES AS A RESULT...AND MAY NEED TO DO SOMETHING SIMILAR
IN OUR SOUTHERN ZONES.
EXCESSIVE HEAT WILL FINALLY BE THE MAIN STORY THEN INTO FRIDAY
AND SATURDAY AS SUBTROPICAL RIDGE BUILDS NORTH (592 DAM HEIGHTS AT
500 MB) AND BAROCLINIC WESTERLIES SHIFT FARTHER NORTH TOWARD THE
US/CANADA BORDER. THE MAIN/ACTIVE FRONTAL ZONE ON THE SOUTHERN
FRINGE OF THESE ZONAL WESTERLIES WILL SET UP FROM THE UPPER
MIDWEST EAST INTO THE CENTRAL/NORTHERN GREAT LAKES DURING THIS
TIME. THIS SHOULD ALLOW A PLAINS EML CAP TO BUILD IN LOCALLY WITH
CONVECTIVE COMPLEXES FOCUSED NORTH AND NORTHWEST OF THE IWX CWA.
WITH THAT SAID, CANNOT COMPLETELY RULE OUT CONVECTION (10-30%
POPS) LATER TONIGHT-FRIDAY IN LOWER MI/FAR NW OH, AND AGAIN
SATURDAY AFTERNOON ACROSS THE ENTIRE AREA, AS OUTFLOW BOUNDARIES
POSSIBLY SURVIVE INTO THIS INCREASINGLY UNSTABLE/HUMID AIRMASS.
OVERALL EXPECTATIONS ARE FOR MAINLY DRY CONDITIONS TONIGHT THROUGH
SATURDAY, WITH HEAT AND HUMIDITY THE MAIN CONCERN.
LONG TERM
(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 235 PM EDT THU JUL 18 2019
FRONTAL BOUNDARY AND/OR COMPOSITE OUTFLOW WILL SINK SLOWLY SOUTH
THROUGH THE AREA SATURDAY NIGHT INTO SUNDAY WITH PERIODIC CHANCES
FOR SHOWERS/STORMS. LOCALLY HEAVY RAINFALL AND ISOLATED
STRONG/SEVERE STORMS APPEAR BE THE PRIMARY THREATS. MAINLY DRY
WEATHER, MUCH LOWER HUMIDITY LEVELS, AND TEMPS NEAR TO SLIGHTLY
BELOW NORMAL WILL FOLLOW THIS FRONTAL PASSAGE FOR MUCH OF NEXT
WEEK.
AVIATION
(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 120 PM EDT THU JUL 18 2019
CONVECTION WILL KEEP CONFIDENCE LOW FOR THE 18Z TAF CYCLE. PRIMARY
LINE OF CONVECTION HAS JUST MOVED THROUGH THE KFWA TERMINAL WHILE
GENERAL SHOWERS ARE PREVAILING AT KSBN. HAVE HELD ONTO TEMPO GROUP
FOR KFWA WHILE KEEPING SHOWERS PREVAILING AT KSBN FOR THE FIRST
FEW HOURS. IN GENERAL A BROAD AREA OF CONVECTION WILL SLOWLY
PROGRESS TO THE EAST THROUGH 21Z. HAVE THEN GONE WITH A GENERAL
IMPROVING TREND WITH VFR CONDITIONS THROUGH THE OVERNIGHT HOURS.
GUSTY WINDS ARE POSSIBLE.
IWX WATCHES/WARNINGS/ADVISORIES
IN...EXCESSIVE HEAT WARNING UNTIL 8 PM EDT SATURDAY FOR INZ009-017-
018-020-022>027-032>034.
EXCESSIVE HEAT WARNING FROM 8 AM EDT /7 AM CDT/ FRIDAY TO 8 PM
EDT /7 PM CDT/ SATURDAY FOR INZ003>008-012>016.
MI...EXCESSIVE HEAT WARNING FROM 8 AM FRIDAY TO 8 PM EDT SATURDAY FOR
MIZ077>081.
OH...EXCESSIVE HEAT WARNING UNTIL 8 PM EDT SATURDAY FOR OHZ001-002-
004-005-015-016-024-025.
LM...NONE.
SYNOPSIS...STEINWEDEL
SHORT TERM...STEINWEDEL
LONG TERM...STEINWEDEL
AVIATION...CM
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