521
FXUS63 KIWX 211739
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
139 PM EDT THU OCT 21 2021
SYNOPSIS
ISSUED AT 653 AM EDT THU OCT 21 2021
NOTABLY COOLER TODAY WITH NEARLY STEADY TEMPERATURES. SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS EAST OF INTERSTATE 69 WILL
TAPER OFF BY LATE MORNING. HOWEVER, ADDITIONAL RAIN SHOWERS ARE
POSSIBLE FOR SOME THIS AFTERNOON. OTHERWISE, EXPECT PARTLY TO
MOSTLY CLOUDY SKIES WITH GUSTY WEST WINDS AND TEMPERATURES IN THE
50S. SEASONABLY COOL THIS WEEKEND WITH WET WEATHER POSSIBLE
SUNDAY.
SHORT TERM
(TODAY AND TONIGHT)
ISSUED AT 409 AM EDT THU OCT 21 2021
SHOWERS AND THUNDERSTORMS ALONG A COLD FRONT WILL EXIT FROM WEST TO
EAST THROUGH THE REMAINDER OF THE EARLY MORNING HOURS. THE PARENT
UPPER- LEVEL LOW WILL GRADUALLY MEANDER EAST TODAY THROUGH
SOUTHERN MICHIGAN. ADEQUATE MOISTURE IS FOUND IN THE LOW- LEVELS,
AND SHOWERS ARE ONGOING IN THE VICINITY OF THE UPPER-LEVEL LOW.
SO, RAIN SHOWERS WILL REMAIN IN THE FORECAST TODAY FOR THOSE
NORTH OF US 24. LAPSE RATES AND INSTABILITY ARE MAXIMIZED ALONG
THE COLD FRONT, SO THE CHANCE OF THUNDER THIS AFTERNOON FROM THE
UPPER- LEVEL LOW IS MINIMAL.
DRY AIR ARRIVES OVERNIGHT, BRINGING AN END TO THE RAIN CHANCES.
SEASONABLY COLD TONIGHT WITH LOWS NEAR 40 FOR MOST; MID- 40S FOR
THOSE TOWARD WEST-CENTRAL INDIANA. AS AN ASIDE, THROUGH THE 20TH,
FORT WAYNE IS STILL EXPERIENCING THE WARMEST START TO OCTOBER WITH
AN AVERAGE TEMPERATURE OF 64.6. SOUTH BEND IS SEEING THEIR 2ND
WARMEST (BEHIND OCTOBER 1928), WITH AN AVERAGE TEMPERATURE OF
65.3.
LONG TERM
(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 409 AM EDT THU OCT 21 2021
CYCLONIC FLOW ALOFT WILL PREVAIL FRIDAY AND SATURDAY THANKS TO AN
UPPER-LEVEL LOW OVER EASTERN ONTARIO. THIS SENDS LOBES OF VORTICITY
THROUGH OUR AREA, WITH PERHAPS THE MOST PRONOUNCED LOBE PASSING
THROUGH FRIDAY NIGHT/SATURDAY. MOISTURE ALOFT IS LACKING BY THAT
TIME, SO THE DRY FORECAST WILL CONTINUE. OUR COLDEST LOWS OF THE
FALL SEASON LOOM SATURDAY NIGHT, ESPECIALLY IN SOUTH- CENTRAL
MICHIGAN WHERE LOWS IN THE MID-30S ARE FORECAST. PATCHY FROST HAS
BEEN INTRODUCED.
A WARM FRONT LIFTS IN ON SUNDAY AND STALLS OVER OUR AREA, LIKELY
BRINGING WIDESPREAD RAIN TO THE AREA AS THE DAY PROGRESSES. FLOW
THROUGH THE MID-LEVELS IS PARALLEL TO THE WARM FRONT AND CONVERGENT
OVER NORTHERN INDIANA. THIS IS PAIRED WITH PWATS NEAR THE 90TH
PERCENTILE FOR THIS TIME OF YEAR. AS A RESULT, THERE IS A NON-
ZERO THREAT OF LOCALLY HEAVY RAIN. THE SURFACE LOW EXITS MONDAY
NIGHT AT WHICH POINT RAIN CHANCES GRADUALLY DIMINISH.
WE'LL MOST LIKELY BE BETWEEN SYSTEMS BY MIDWEEK WITH A TROUGH TO
BOTH OUR WEST AND OUR EAST. DETERMINISTIC MODELS HAVE TRENDED DRY
ON WEDNESDAY WITH THIS 00Z RUN, BUT ENSEMBLES STILL OFFER THE
CHANCE FOR WET WEATHER. I HAVE BLENDED THE PREVIOUS AND LATEST
FORECASTS, WITH A FURTHER POP REDUCTION THEREAFTER. THE WESTERN
TROUGH AXIS SWINGS THROUGH THURSDAY NIGHT.
AVIATION
(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 139 PM EDT THU OCT 21 2021
A COLD FRONT HAS BEEN TRAVERSING WEST TO EAST ACROSS THE REGION
TODAY. LATEST RADAR TRENDS HAVE SHOWN THE INITIAL PRECIPITATION
TO BE WELL EAST OF THE TERMINAL SITES. WITH THE APPROACH OF THE
UPPER LOW REDEVELOPMENT OF SHRA IS EXPECTED THIS AFTN THAT COULD
IMPACT THE KSBN TERMINAL LATER IN THE AFTN/EVENING TIME PERIOD.
EXPECT MVFR CIGS AT KSBN THROUGH THE FCST PD WHILE BEGINNING AS
MVFR AT KFWA AND IMPROVING TO VFR AFTER 08Z TONIGHT. WEST WINDS
GUSTING TO 25 KTS AT TIMES WILL TURN NW THIS EVENING CLOSER TO
00Z.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 11 AM EDT FRIDAY FOR LMZ043-046.
SYNOPSIS...BROWN
SHORT TERM...BROWN
LONG TERM...BROWN
AVIATION...MF
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