290
FXUS63 KIND 091048
AFDIND
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
648 AM EDT FRI MAY 9 2025
KEY MESSAGES
- BRIEFLY COOLER TODAY, THEN WARMER TEMPERATURES THIS WEEKEND INTO
NEXT WEEK
- MAINLY ISOLATED/SCATTERED SHOWERS/T-STORMS MONDAY-WEDNESDAY
- EXPECT VERY WARM CONDITIONS W/MODERATE HUMIDITY LATE NEXT WEEK
SHORT TERM (TODAY AND TONIGHT)
ISSUED AT 300 AM EDT FRI MAY 9 2025
NORTHEASTERLY WINDS BETWEEN 10 TO 15 MPH REMAIN AHEAD OF AN
APPROACHING SURFACE HIGH FROM THE NORTH. WINDS GRADUALLY DIE DOWN
THROUGH THE AFTERNOON TODAY AS THE SURFACE HIGH CENTER ARRIVES THIS
EVENING. LIGHT AND VARIABLE TO CALM WINDS THEN PERSIST THROUGH THE
REMAINDER OF THE SHORT TERM PERIOD.
THE AIR MASS ARRIVING WITH THE HIGH IS FAIRLY DRY, ESPECIALLY
BETWEEN 925MB AND 500MB. LITTLE IN THE WAY OF CLOUD COVER IS
ANTICIPATED GIVEN THE DRY AND SUBSIDENT COLUMN. THERE IS A BIT OF
MOISTURE AT 250MB ALONG WITH A NORTHEAST TO SOUTHWEST ORIENTED JET
STREAK, WHICH COULD LEAD TO SOME THIN CIRRUS AT TIMES.
BACK TOWARDS THE SURFACE, MODEL SOUNDINGS SHOW FAIRLY DEEP MIXING
WHICH WILL PROMOTE TEMPERATURES REBOUNDING INTO THE HIGH 60S TO NEAR
70. OUR PRIMARY FORECAST CHALLENGE MAY BE DEW POINTS, GIVEN THE VERY
DRY AIR LOCATED BETWEEN 925MB AND 850MB. GUIDANCE CAN STRUGGLE WITH
DEEP BOUNDARY LAYER MIXING AND FAIL TO CAPTURE HOW MUCH DRY AIR
MIXES TO THE SURFACE. WE WILL ADD MORE WEIGHT TO THE HRRR (WHICH MAY
BE TOO DRY) IN ORDER TO BRING TDS DOWN A BIT. RELATIVE HUMIDITY
VALUES MAY DROP AS LOW AS 20-25 PERCENT, ESPECIALLY ACROSS OUR
NORTHERN COUNTIES.
LIGHT AND VARIABLE WINDS ALONG WITH MAINLY CLEAR SKIES WILL PROMOTE
IDEAL RADIATIONAL COOLING CONDITIONS TONIGHT. TEMPERATURES SHOULD
DROP QUICKLY AFTER SUNSET AND FALL INTO THE 40S FOR MOST LOCATIONS.
A FEW ISOLATED LOCATIONS MAY DIP INTO THE UPPER 30S. NOT EXPECTING
MUCH IN THE WAY OF FOG, GIVEN THE DRY ATMOSPHERE IN PLACE...BUT SOME
PATCHY GROUND FOG CANNOT BE RULED OUT OVER SOUTHERN INDIANA IN
TYPICALLY FOG-PRONE LOCATIONS.
LONG TERM (SATURDAY THROUGH THURSDAY)
ISSUED AT 312 AM EDT FRI MAY 9 2025
A BROAD AND OVERALL RETRACTED UPPER-LEVEL PATTERN IN A SORT OF WEAK
REX-BLOCK FORMATION WILL PROMOTE A SLOW TRANSITION...FROM PLEASANT
LATE-SPRING CONDITIONS THIS WEEKEND...TO OCCASIONAL SHOWERS, AMID
INCREASING HUMIDITY, AND EVENTUALLY WARMTH, BY THE MIDDLE OF NEXT
WEEK. BROAD YET RATHER WEAK SURFACE HIGH PRESSURE EXTENDING FROM
EASTERN ONTARIO TO THE OHIO VALLEY THIS WEEKEND WILL PROVIDE LIGHT
BREEZES UNDER MOSTLY CLEAR SKIES, WHILE ABOVE NORMAL HEIGHTS BRING
READINGS INDICATIVE OF LATE MAY, RANGING FROM THE 50S TO MID/UPPER
70S.
DRY CONDITIONS THROUGH SUNDAY NIGHT WILL BE REPLACED BY CHANCES FOR
ISOLATED TO SCATTERED SHOWERS/T-STORMS THAT SHOULD EXHIBIT
DIURNAL ENHANCEMENT, ACROSS THE MONDAY TO WEDNESDAY TIMEFRAME.
STACKED YET WEAK LOW PRESSURE OVER THE LOWER MISSISSIPPI VALLEY
WILL SLOWLY LIFT TOWARDS THE MIDWEST AS THE BLOCKED SLOWLY BREAKS
DOWN. AMPLE PRECIPITABLE WATER VALUES IN THE 1.25-1.50 INCH RANGE
AND SURFACE DEWPOINTS CLIMBING THROUGH THE 50S TO AT LEAST THE LOW
60S WILL POSE THE POTENTIAL FOR PRECIPITATION, ALTHOUGH
DISORGANIZED LIFT FROM THE BROAD TROUGH'S REMNANT FRAGMENTS
SHOULD LIMIT HEAVIER RAINFALL TO ISOLATED LOCATIONS.
TOWARDS THE END OF THE LONG TERM, THE LEFT-OVER SOUTHERN
CIRCULATION SHOULD INTERACT WITH A MORE NORTHERN-STREAM TROUGH
NEAR THE HIGH PLAINS TO ACT AS A SORT OF WARM-FRONTAL ZONE...AHEAD
OF AN UPPER SUBTROPICAL RIDGE BUILDING NORTHWARD FROM THE
SOUTHERN PLAINS. THIS MAY WELL ALLOW THE LOCAL REGION'S FIRST VERY
WARM TO PERHAPS MARGINALLY HOT DAYS OF THE YEAR, WITH WIDESPREAD
MID TO UPPER 80S ON THE TABLE FOR THE LATE WORKWEEK SHOULD THE
PATTERN TREND AS CURRENTLY EXPECTED. THE NORMAL MAX/MIN AT
INDIANAPOLIS THROUGH THE LONG TERM IS 72/52.
AVIATION (12Z TAF ISSUANCE)
ISSUED AT 647 AM EDT FRI MAY 9 2025
IMPACTS:
- NONE.
DISCUSSION:
VFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD.
NORTHEASTERLY WINDS AROUND 10 KNOTS SHOULD PERSIST THIS MORNING
HOURS BEFORE TAPERING OFF DURING THE AFTERNOON. WINDS DIE DOWN EVEN
FURTHER BECOMING LIGHT AND VARIABLE TONIGHT INTO SATURDAY. WINDS
TURN NORTHWESTERLY SATURDAY AFTERNOON BUT REMAIN LIGHT.
CLOUD COVER SHOULD BE LIMITED TO OCCASIONAL THIN CIRRUS.
IND WATCHES/WARNINGS/ADVISORIES
NONE.
SHORT TERM...ECKHOFF
LONG TERM...AGM
AVIATION...ECKHOFF
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