270
FXUS63 KIWX 270833
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
433 AM EDT SUN APR 27 2025
KEY MESSAGES
- COLD START THIS MORNING WITH SOME LOCATIONS DROPPING INTO THE
LOWER TO MID 30S. FROST ADVISORY FOR NORTHERN PARTS OF THE CWA
THROUGH 8 AM EDT. TEMPERATURES THEN TREND WARMER THROUGH
TUESDAY.
- THUNDERSTORMS POSSIBLE ACROSS THE AREA EARLY TUESDAY MORNING
THROUGH EARLY WEDNESDAY MORNING. BEST CHANCES FOR SEVERE
THUNDERSTORMS WILL BE FOR LOCATIONS SOUTHEAST OF I-69 ON
TUESDAY AFTERNOON AND EVENING. MAIN THREATS WILL BE GUSTY
WINDS AND LARGE HAIL. AN ISOLATED TORNADO OR TWO WOULD ALSO BE
POSSIBLE.
- AFTER A BRIEF REPRIEVE, RAIN QUICKLY RETURNS TO THE AREA MID
TO LATE WEEK WITH THUNDERSTORMS ALSO POSSIBLE AT TIMES.
DISCUSSION
ISSUED AT 317 AM EDT SUN APR 27 2025
COLD START THIS MORNING WITH A FEW LOCATIONS ACROSS THE
NORTHWEST PORTIONS OF THE CWA CURRENTLY AS OF 3 AM EDT DOWN TO
AROUND 33 DEGREES THIS MORNING. KSBN WAS REPORTING 36 DEGREES.
WILL SEE TEMPERATURES REBOUND LATER TODAY WITH RIDGING PUSHING
EASTWARD INTO THE REGION AND LIGHT WINDS TURNING MORE
SOUTHEASTERLY. DRIER AIRMASS STILL IN PLACE WITH DEW POINTS IN
THE UPPER 30S TO LOW 40S. HIGHS IN THE 60S ACROSS THE AREA
TODAY.
MONDAY WE START TO SEE SOUTHERLY WINDS INCREASING, GUSTS UP TO
35 MPH POSSIBLE, WHICH WILL START TO BRING AN INFLUX OF
MOISTURE WITH DEW POINTS INCREASING INTO THE UPPER 40S TO UPPER
50S BY MONDAY AFTERNOON. THIS IS AHEAD OF A SURFACE LOW PRESSURE
SYSTEM THAT PULLS OUT OF THE FOUR-CORNERS REGION AND MOVES
NORTHEASTWARD TOWARDS THE GREAT LAKES REGION BY TUESDAY. HIGHS
ON MONDAY WILL BE WARMER YET WITH TEMPERATURES IN THE 70S WITH A
FEW LOCATIONS IN OUR SOUTHWEST PARTS OF THE CWA PERHAPS GETTING
INTO THE LOWER 80S. THAT LOW PRESSURE SYSTEM WILL BRING SEVERE
WEATHER TO EASTERN IA, NORTHERN IL, AND SOUTHERN WI ON MONDAY
AFTERNOON AND EVENING. FURTHER INFLUX OF MOISTURE WILL CONTINUE
AHEAD OF THE COLD FRONT INTO THE AREA LATE MONDAY NIGHT INTO
EARLY TUESDAY AND SURFACE DEW POINTS WILL GET INTO THE 60S BY
TUESDAY MORNING.
THE RECENT GUIDANCE HAS BEEN INDICATING THAT THE COLD FRONT
WILL APPROACH OUR AREA A BIT EARLIER THAN ORIGINALLY THOUGHT.
ARRIVING BY EARLY TUESDAY MORNING. THIS WILL INCREASE CHANCES
OF SHOWERS AND THUNDERSTORMS TO ENTER THE WESTERN PORTIONS OF
THE CWA AROUND 1-2 AM EDT TUESDAY. A STRONG STORM WOULD STILL BE
POSSIBLE AS THE FRONT ARRIVES BUT WITH THE NIGHTTIME ARRIVAL
WILL HELP TO MITIGATE THE STRENGTH OF THE STORMS. THE EARLIER
FRONTAL PASSAGE WILL ALSO KEEP A MAJORITY OF THE AREA IN A NOT
SO IDEAL DIURNAL HEATING SETUP AND FURTHERMORE CAUSE INCREASED
CLOUD COVER ACROSS THE AREA WHICH WILL HELP TO MITIGATE DIRECT
SOLAR INSOLATION AND SUBSEQUENT SURFACE WARMING. MU CAPE VALUES
ON TUESDAY AFTERNOON WILL BE AROUND 1000-1500 J/KG, MID LEVEL
LAPSE RATES AROUND 6-7 DEG/KM, AND BULK SHEAR VALUES OF 30 TO
35 KTS. THESE INGREDIENTS DO MAKE FOR THE POTENTIAL FOR SOME
ORGANIZED SEVERE THREATS INCLUDING STRONG GUSTY WINDS AND HAIL.
A FEW ISOLATED TORNADOES WOULD NOT BE OUT OF THE QUESTION AS
HELICITY VALUES SOUTHEAST PORTIONS OF THE CWA WILL BE AROUND
100 M2/S2. SPC DAY 3 CONVECTIVE OUTLOOK DOES CURRENTLY HAVE OUR
SOUTHWEST PORTIONS OF THE CWA IN A SLIGHT RISK ON TUESDAY.
THE COLD FRONTAL BOUNDARY WILL PUSH SOUTHEAST BY EARLY
WEDNESDAY MORNING BUT WILL BECOME MORE ORIENTATED IN A EAST TO
WEST DIRECTION OVER THE SOUTHERN PORTIONS OF THE AREA AND BECOME
MORE OF A QUASI-STATIONARY BOUNDARY BEFORE PUSHING BACK
NORTHWARD AS A WARM FRONTAL BOUNDARY ON WEDNESDAY BRINGING
ISENTROPIC SHOWERS AND A FEW AFTERNOON THUNDERSTORMS ON
WEDNESDAY. ANY STORMS ARE NOT EXPECTED TO BE SEVERE AT THIS TIME.
HIGHS ON WEDNESDAY WILL BE IN THE 60S ACROSS THE AREA WITH THE
WARMER TEMPERATURES FOR THE SOUTHERN HALF OF THE AREA WHERE A
FEW LOCATIONS MAY SEE LOW 70S.
THE BOUNDARY PUSHES FURTHER NORTHWARD ON THURSDAY AGAIN WITH
INCREASED CHANCES OF RAIN SHOWERS AND EMBEDDED THUNDERSTORMS,
WITH THE BETTER CHANCES FOR T-STORMS ON THURSDAY AFTERNOON.
HIGH TEMPERATURES WARM BACK INTO THE UPPER 60S AND LOW 70S
ALBEIT TEMPORARILY AS TROUGHING OVER THE CENTRAL CONUS PUSHES
EASTWARD AND BRINGS COOLER TEMPERATURES AND DRIER CONDITIONS TO
THE AREA INTO THE WEEKEND. FRIDAY THROUGH SUNDAY HIGH
TEMPERATURES WILL ONLY BE IN THE LOW TO MID 60S.
AVIATION /06Z TAFS THROUGH 06Z MONDAY/
ISSUED AT 120 AM EDT SUN APR 27 2025
HIGH PRESSURE CENTERED RIGHT OVER THE UPPER GREAT LAKES REGION
TONIGHT WILL KEEP BOTH TERMINALS VFR WITH SOME HIGH CLOUDS AND
NEARLY CALM WINDS. AFTER SUNRISE WINDS STRENGTHEN OUT OF THE ESE
TO ABOUT 5-9 KNOTS. WE COULD SEE BRIEF MVFR CONDITIONS FROM BR
AT KFWA THIS MORNING WHERE LOW LEVEL MOISTURE RESIDES UNDER
FAVORABLE RADIATIONAL COOLING CONDITIONS/LIGHT WINDS. LEFT OUT
OF THE TAF FOR NOW GIVEN UNCERTAINTIES REGARDING THE IMPACT OF
THESE HIGH CLOUDS ON RADIATIONAL COOLING. GUIDANCE IS CONFLICTED
ON THIS AS WELL, SO WILL ADDRESS WITH AMENDMENTS IF NEEDED.
IWX WATCHES/WARNINGS/ADVISORIES
IN...FROST ADVISORY UNTIL 8 AM EDT /7 AM CDT/ THIS MORNING FOR
INZ005>008-012-014-103-104-116-203-204.
OH...NONE.
MI...FROST ADVISORY UNTIL 8 AM EDT THIS MORNING FOR MIZ078>081-177-
277.
MARINE...NONE.
DISCUSSION...ANDERSEN
AVIATION...MCD
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