440
FXUS63 KLMK 051727
AFDLMK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
127 PM EDT MON OCT 5 2026
KEY MESSAGES
* SEASONABLY MILD WEATHER WILL KICK OFF THE WEEK WITH HIGHS
GENERALLY IN THE 70S THROUGH TUESDAY. MANY LOCATIONS WILL CLIMB
BACK INTO THE 80S WEDNESDAY THROUGH SATURDAY.
* OVERNIGHT LOW TEMPERATURES MAY FALL INTO THE UPPER 30S IN LOW-
LYING RURAL AREAS MONDAY NIGHT, BUT THE PROBABILITY OF FROST IS
LOW.
* MILD-MODERATE DROUGHT CONDITIONS, WORST OVER SOUTHERN KENTUCKY,
WILL WORSEN THIS WEEK AS DRY WEATHER PREVAILS. THE NEXT (40-60%)
CHANCE FOR BENEFICIAL RAINFALL WILL ARRIVE LATE SATURDAY EVENING
INTO SUNDAY.
DISCUSSION
ISSUED AT 305 AM EDT MON OCT 5 2026
LOOKING AT A NEARLY PICTURE PERFECT STRETCH OF WEATHER AS WE ENTER
THE FIRST PART OF THE NEW WORK WEEK. EXPANSIVE HIGH PRESSURE WILL
BUILD INTO THE GREAT LAKES REGION TODAY, AND THEN SLIDE ESE TO THE
MID ATLANTIC COAST BY TUESDAY. MEANWHILE, UNREMARKABLE/DRY NW FLOW
ALOFT WILL DOMINATE THE UPPER PATTERN. OTHER THAN A FEW HIGH CLOUDS
ACROSS SOUTHERN AND CENTRAL KY THIS MORNING, THIS EARLY WEEK PATTERN
WILL YIELD VIRTUALLY CLOUDLESS SKIES AND LIGHT TO STEADY NNE TO ENE
WINDS. WILL BE KIND OF INTERESTING TO SEE WHERE TEMPS END UP GIVEN
THE FULL SUN, BUT ALSO A SOMEWHAT LIMITING NE SURFACE FLOW. IT
IS CREATING A FAIRLY IMPRESSIVE SPREAD BETWEEN MAV/MET GUIDANCE
FOR TODAY, AND HAVE TENDED TO LAND IN THE MIDDLE BETWEEN THE
MILDER MAV AND MUCH COOLER MET. THIS SHOULD YIELD HIGHS MOSTLY
IN THE MID 70S TODAY AND TOMORROW.
A VERY WELL MIXED BOUNDARY LAYER THIS AFTERNOON WILL LIKELY YIELD
IMPRESSIVE DRY AIR MIX DOWN GIVEN MIXING HEIGHTS EXTENDING UP INTO A
NOTABLE HYDROLAPSE ABOVE 900MB. SOMETHING TO BE MINDFUL OF AS WE DRY
OUT FROM THE WEEKEND RAIN THIS UPCOMING WORK WEEK.
LOOK FOR SOME CRISP TO DOWN RIGHT COOL OVERNIGHT LOWS AS WELL GIVEN
LIGHT SURFACE WINDS AND CLOUDLESS SKIES. RADIATIONAL COOLING SHOULD
ALLOW FOR MOST MIN TEMPS IN THE 45-50 DEGREE RANGE TONIGHT, HOWEVER
SOME LOWER 40S WILL BE MORE COMMON ACROSS THE NE CWA CLOSER TO THE
CENTER OF THE SURFACE HIGH OVER THE OH/PA/WV CONFLUENCE. COULD SEE
SOME OF THE COOLEST SHELTERED VALLEYS DROP INTO THE UPPER 30S AS
THEY COMPLETELY DECOUPLE FROM A LIGHT SURFACE WIND. NOT SURE WE WILL
GET COLD ENOUGH FOR ANY FROST CONCERNS, BUT IF SO, IT WOULD BE
EXTREMELY ISOLATED. UNLIKELY WOULD BE A GOOD WAY TO CHARACTERIZE IT.
TUESDAY NIGHT LOWS WILL COULD BE A TOUCH MILDER (46 TO 51F FOR MOST)
AS THE SURFACE HIGH SLIDES EAST OF THE AREA AND A VERY LIGHT S
SURFACE FLOW RETURNS BY DAWN WEDNESDAY. THAT BEING SAID, SOME LOW
40S ARE STILL EXPECTED FOR THE COOLER NE CWA VALLEYS.
WEDNESDAY - SUNDAY...
SLIGHTLY WARMER THAN AVERAGE TEMPERATURES AND LOW RH PERSIST
THROUGHOUT THE WEEK; ESPECIALLY PREVALENT WEDNESDAY, THURSDAY, AND
FRIDAY, WE COULD SEE MAX TEMPS IN THE MID-80S WITH MIN DEW POINTS
PUSHING THE LOW-40S. LIGHT SURFACE FLOW OUT OF THE SOUTHWEST ON WED
AND THE NORTH/NORTHWEST ON THURS AS A WEAK SFC HIGH SITS OVER THE
RIDGE OF THE APPALACHIANS. A THICK MIXING LAYER DURING THE DAY AND
THE LOW RH VALUES SHOULD PREVENT THE OVERNIGHT LOW-LEVEL INVERSION
FROM CREATING FOG EXCEPT IN LOW-LYING RIVER AREAS. OVERNIGHT LOWS
SHOULD REMAIN IN THE UPPER 40S AND LOW 50S FOR
WEDNESDAY/THURSDAY/FRIDAY NIGHTS.
SATURDAY AND SUNDAY IS A BIT OF A DIFFERENT STORY, WITH A POTENTIAL
FOR OUR NEXT RAIN AS TROPICAL MOISTURE PUSHES ITS WAY NORTH. WHILE
THIS IS STILL A WEEK OUT, THE LAST SEVERAL MODEL RUNS HAVE BEEN
CONSISTENT WITH THE MOISTURE, WITH THE ECMWF BEING THE ONLY OUTLIER.
RAINFALL TOTALS COULD SEE AROUND AN INCH FOR THE SOUTHERN PORTION OF
THE CWA, WITH THE SYSTEM CREATING A SHARPER GRADIENT OF A QUARTER
INCH FOR THE SOUTHERN INDIANA PORTION. AS THIS OCCURS, MID- TO LOW-
LEVEL CLOUDS SHOULD SET IN ACROSS THE CWA, LIMITING OUR DECOUPLING
POTENTIAL AT NIGHT AND KEEPING RH HIGHER AND OVERNIGHT MINS IN THE
UPPER-50S AND LOW-60S. DAYTIME HIGHS ARE A LITTLE MUGGIER WITH
HIGHER DAYTIME DEWPOINTS AND TEMPS IN THE LOW-80S.
AVIATION /18Z TAFS THROUGH 00Z WEDNESDAY/
ISSUED AT 126 PM EDT MON OCT 5 2026
VFR CONDITIONS WILL PREVAIL AS HIGH PRESSURE SHIFTS FROM THE MIDWEST
TODAY INTO THE APPALACHIANS TOMORROW. CONSEQUENTLY, NORTHEAST WINDS
AROUND 8-13 KT THIS AFTERNOON WILL EASE THIS EVENING AND VEER TO AN
EASTERLY DIRECTION TOMORROW MORNING. WE SHOULD HOLD ONTO ENOUGH OF A
WIND OVERNIGHT TO PREVENT FOG FORMATION, THOUGH IT CAN'T BE
COMPLETELY RULED OUT AT RGA AND HNB (5-10% CHANCE).
LMK WATCHES/WARNINGS/ADVISORIES
KY...NONE.
IN...NONE.
DISCUSSION...BJS/JPH
AVIATION...JRB
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page