440
FXUS63 KIWX 130525
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
125 AM EDT FRI JUN 13 2025
KEY MESSAGES
- AN INCREASING CHANCE (40% TO 70%) FOR SHOWERS AND
THUNDERSTORMS FRIDAY MORNING THROUGH AT LEAST SATURDAY.
- PERIODS OF HEAVY RAIN POSSIBLE SATURDAY AFTERNOON.
- SEASONABLY WARM WITH HIGHS IN THE 80S OR NEAR 80 THROUGH THE
NEXT SEVEN DAYS.
DISCUSSION
ISSUED AT 218 PM EDT THU JUN 12 2025
THE MID-LATITUATDE JET IS DISPLACED POLEWARD, ALONG THE NORTHERN US
BORDER, AS SEEN ON WATER VAPOR THIS AFTERNOON. A WEAK STATIONARY
FRONT IS NOTED ACROSS CENTRAL AND SOUTHERN MI. THIS COULD STILL BE
THE FOCUS FOR AN ISOLATED AFTERNOON THUNDERSTORM. A SECONDARY AREA
OF INTEREST FOR A POP-UP STORM WOULD BE ON THE LAKE ERIE LAKE BREEZE
THAT IS SLOWLY PUSHING WESTWARD INTO WAUSEON, OH. CONFIDENCE IN A
STORM OCCURRING IS LOW PRIMARILY DUE TO WEAK FORCING MECHANISMS AND
LINGERING LOW-LEVEL DRY AIR. YET, NOT ENOUGH CONFIDENCE TO REMOVE
FROM THE INHERITED FORECAST.
ALSO OF NOTE ON WATER VAPOR IS A LOW LIFTING IN FROM THE LOWER-
MISSISSIPPI VALLEY. THIS LOW GRADUALLY LIFTS NORTH ATOP A SOUTHEAST
US RIDGE. THESE LATE-MORNING RUNS OF THE HRRR APPEAR A LITTLE OVER
ZEALOUS WITH THE START TIME OF RAIN FRIDAY WHEN COMPARED TO OTHER
HREF MEMBERS. ADDITIONALLY, CROSS SECTIONS FAVORS A SLOWER ONSET DUE
TO DRY AIR, THUS, THE ARRIVAL TIME FOR SHOWERS HAS SLOWED FOR
FRIDAY. AT LEAST SCATTERED SHOWERS AND THUNDERSTORMS ARE ANTICIPATED
BY THE AFTERNOON WITH AMPLE MOISTURE AND HIGH PRESSURE NOW
DISPLACED OVER WESTERN QUEBEC. SEVERE WEATHER IS NOT EXPECTED DUE TO
MARGINAL INSTABILITY AND WEAK SHEAR NEAR 25 KNOTS.
THIS LOW LINGERS IN THE AREA THROUGH SATURDAY NIGHT. SOME GUIDANCE
IS KEYING IN ON HEAVY RAIN FROM THE DEFORMATION ZONE OF THIS LOW ON
SATURDAY AFTERNOON. SOUNDINGS SHOW A DEEP MOISTURE LAYER THOUGH THE
COLUMN WITH A WARM CLOUD LAYER OF ALMOST 12K FEET, WEAK FLOW, AND
PWATS THAT EXCEED THE 90TH PERCENTILE. THESE ARE INGREDIENTS FOR
LOCALIZED FLOODING THAT WILL NEED TO BE MONITORED. CAN'T RULE OUT A
STRAY SHOWER OR STORM SUNDAY AFTERNOON SOUTHEAST OF US 24 ON THE
WESTERN EDGE OF THE LOW. OTHERWISE, MAINLY DRY.
THE NEXT SHORTWAVE, USHERED ALONG BY THE DISPLACED MID-LATITUDE JET,
ARRIVES MONDAY WITH ANOTHER TO FOLLOW TUESDAY. A SHARP TROUGH MOVING
THROUGH THE UPPER MIDWEST THEREAFTER WILL BE WORTH WATCHING FOR A
SEVERE WEATHER RISK IN THE MIDWEST.
AVIATION /06Z TAFS THROUGH 06Z SATURDAY/
ISSUED AT 114 AM EDT FRI JUN 13 2025
EAST FLOW HAD INCREASED A LITTLE WITH A FAIRLY TIGHT SFC MOISTURE
GRADIENT OVER THE REGION RANGING FROM DEW POINTS NEAR 70 AT RCR
TO THE LOWER 40 OVER FAR SOUTHEAST LOWER MICHIGAN. GFS BUFKIT
SOUNDING SHOWED A DRY AREA IN THE MID LEVELS OVER NORTHERN
INDIANA. THE BIGGEST CHALLENGE IS HOW FAR NORTH THE
PRECIPITATION FROM THE APPROACHING UPPER LOW/TROF WILL MAKE IT.
BACKED OFF A LITTLE BIT AT SBN. IT APPEARS THE HRRR IS AN
OUTLIER AND DOESN'T SEEM TO TAKE INTO ACCOUNT THE SATURATION OF
THE DRY MID LEVEL LAYER. WILL LET CATEGORICAL RAIN RIDE AT FWA
FOR NOW AND WAIT TO SEE IF MODEL AND OBS TRENDS GO ONE WAY OR
THE OTHER.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...NONE.
DISCUSSION...BROWN
AVIATION...SKIPPER
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