075
FXUS63 KLMK 041929
AFDLMK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
229 PM EST SUN DEC 4 2022
SHORT TERM
(THIS EVENING THROUGH MONDAY)
ISSUED AT 211 PM EST SUN DEC 4 2022
A QUIET WEATHER DAY ACROSS SOUTHERN INDIANA AND CENTRAL KENTUCKY
TODAY AS 1030MB HIGH PRESSURE MEANDERS ACROSS THE REGION. MID AND
HIGH CLOUD CONTINUE TO ADORN THE SKIES OVER MUCH OF THE AREA, BUT
CLEARING CONTINUES TO WORK IT'S WAY SOUTHWARD AS PLACES ROUGHLY
NORTH OF I-64 SEE BLUER SKIES PREVAIL. KY MESONET SHOWS TEMPERATURES
REACHING TO AROUND 40 SO FAR TODAY WITH CONTINUED LIGHT AND VARIABLE
WINDS.
EXPECT THE W-E ORIENTED WAVE OF HIGH CLOUD TO UNDULATE OVER THE NEXT
12 HOURS OR SO, AS A GOOD AMOUNT OF CLEARING TAKES PLACE OVER MUCH
OF THE CWA BEFORE FILLING BACK IN OVERNIGHT. THE BREAK IN CLOUD
COVER SHOULD BE ENOUGH TO ALLOW TEMPERATURES TO FALL ONCE AGAIN INTO
THE MID 20S NORTH OF THE PARKWAYS AND TO AROUND AND JUST ABOVE
FREEZING THE CLOSER ONE GETS TO THE KY/TN BORDER.
ON MONDAY, A WEAK SHORTWAVE WILL MOVE THROUGH THE ZONAL PATTERN
ALOFT BRINGING RAIN CHANCES BACK TO THE AREA AS SOUTHERLY FLOW PULLS
MOIST GULF AIR INTO THE REGION WITH PWATS BREACHING THE 90TH
PERCENTILE ACCORDING TO SPC SOUNDING CLIMATOLOGY. THOUGH THERE IS
GOOD AGREEMENT AMONG LATEST HI-RES MODELS ON RAIN ENTERING THE AREA
MONDAY, TIMING DISCREPANCIES EXIST. MOST MODELS KEEP MUCH OF THE
AREA DRY THROUGH THE MORNING, BUT A FEW ADVERTISE ONSET AS EARLY AS
05/12Z NEAR BWG AND AREAS SW. WITH THAT BEING SAID, SOUTHERN KY, SAY
SOUTH OF THE PARKWAYS, STANDS THE BEST CHANCE AT SEEING LIGHT
RAINFALL MONDAY MORNING; OTHERWISE, RAIN SHOULD HOLD OFF UNTIL LATER
MONDAY AFTERNOON. INCREASING CLOUD COVER AND RAINFALL WILL DECREASE
THE EFFECTIVENESS OF WAA ASSOCIATED WITH SOUTHERLY FLOW, WITH
AFTERNOON MAX TEMPERATURES REACHING 45-50F ACROSS SOUTHERN INDIANA
AND NORTH CENTRAL KY AND 50-54F ROUGHLY SOUTH OF I-64. RAIN AND A
GENERAL WET PATTERN WILL CONTINUE INTO THE LONG TERM PERIOD...MORE
ON THAT BELOW.
LONG TERM
(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 226 PM EST SUN DEC 4 2022
*********************************************************************
KEY MESSAGES FOR NEXT WEEK:
1) MULTIPLE ROUNDS OF RAINFALL EXPECTED THROUGH MUCH OF NEXT WEEK.
LATEST TREND IN MODELS HAS BEEN TO SHIFT THE HEAVIEST AXIS OF RAIN
FROM CENTRAL TENNESSEE INTO CENTRAL KENTUCKY.
2) SEVERAL INCHES OF RAINFALL WILL BE POSSIBLE BY THE END OF THE
WEEK. SOME OF THIS COULD RESULT IN HYDRO ISSUES, ESPECIALLY IF THE
HEAVY RAINFALL AXIS SETS UP OVER OUR REGION.
3) A THREAT FOR STRONG OR SEVERE STORMS, CONDITIONAL ON LOW TRACK
AND ANY AVAILABLE INSTABILITY, WILL BE POSSIBLE THURSDAY INTO EARLY
FRIDAY.
*********************************************************************
AN UNSETTLED PATTERN LOOKS TO DEVELOP IN THE LONG TERM WITH MULTIPLE
ROUNDS OF PRECIPITATION LEADING TO POTENTIALLY SEVERAL INCHES OF
ACCUMULATED RAINFALL BY THE END OF THE WEEK. A FRONTAL BOUNDARY OVER
THE SOUTHERN U.S. WILL LIFT NORTHWARD NEAR OUR REGION AND WAVER
THROUGH MIDWEEK, ALL WHILE SEVERAL PERTURBATIONS/WAVES WITHIN A
SUBTROPICAL JET AT THE MID/UPPER LEVELS PASS OVERHEAD. COMBINE THIS
WITH A NEAR CONSTANT, ENHANCED LOW/MID LEVEL MOISTURE FLUX OFF OF
THE GULF OF MEXICO ALONG WITH SOME PACIFIC INFLUENCES... WIDESPREAD
RAINS ARE A NEAR CERTAINTY FOR MOST.
RAINFALL WILL LIKELY BE ONGOING FOR PORTIONS OF THE REGION MONDAY
NIGHT AS THE FIRST WAVE ARRIVES. WE MAY SEE BREAKS IN SUBSEQUENT
WAVES OF MOISTURE, BUT THEY WILL LIKELY BE SHORT-LIVED UNTIL ABOUT
THURSDAY NIGHT OR FRIDAY WHEN A SHORTWAVE TROUGH AND ASSOCIATED COLD
FRONT KICKS THROUGH THE REGION AND UPPER LEVEL RIDGING BUILDS IN
BEHIND IT TO CHANGE UP THE PATTERN A BIT. A CONCERNING TREND IN
MODELS OVER THE LAST 24 HOURS HAS BEEN TO SHIFT THE HEAVY RAIN AXIS
FARTHER NORTH INTO CENTRAL KENTUCKY (WHEREAS PREVIOUSLY IT WAS OVER
CENTRAL TENNESSEE). WE'VE SEEN MODELS WAVER WITH THE HEAVY RAIN AXIS
OVER THE LAST SEVERAL DAYS, SO NOTHING IS SET IN STONE YET, BUT IT'S
WORTH MONITORING BECAUSE ENSEMBLE MEAN/AVERAGES IN THE HEAVIEST RAIN
AXIS TEND TO EXCEED 3", AND LOCALLY HIGHER AMOUNTS ARE A NEAR
CERTAINTY GIVEN POTENTIAL FOR CONVECTIVELY ENHANCED RAINFALL (WHICH
COARSER MODELS WON'T RESOLVE).
GIVEN DRY ANTECEDENT CONDITIONS, WE SHOULD BE ABLE TO HANDLE A LOT
OF THE RAIN FAIRLY WELL THROUGH THE FIRST PART OF THE WEEK, BARRING
ANY SIGNIFICANT LOCALIZED/PERSISTENT HEAVY RAINS. AS WE GET CLOSER
TO THE END OF THE WEEK, DEPENDING ON WHERE THE HEAVY RAIN AXIS HAS
SET UP, WE MAY BEGIN TO SEE SOME HYDRO ISSUES ARISE AS SOGGY SOILS
WILL BE LESS INCLINED TO ABSORB MODERATE TO HEAVY RAINFALL AHEAD OF
THE SHORTWAVE TROUGH AND SURFACE COLD FRONT FOR THURSDAY/EARLY
FRIDAY. WE MIGHT ALSO HAVE TO KEEP AN EYE OUT ON A LOW-END SEVERE
THREAT THURSDAY INTO EARLY FRIDAY, DEPENDING ON THE TRACK OF THE LOW
AND HOW FAR NORTH RICH LOW-LEVEL MOISTURE ADVECTS POLEWARD. THERE
WILL BE PLENTY OF SHEAR IN PLACE AHEAD OF THE COLD FRONT, BUT
INSTABILITY REMAINS VERY UNCERTAIN FOR ANY SEVERE POTENTIAL.
THE SHORTWAVE TROUGH AND FRONT SHOULD CLEAR THE REGION SOMETIME
FRIDAY. DRY CONDITIONS ARE EXPECTED IN ITS WAKE AS UPPER LEVEL
RIDGING BUILDS IN, BUT IT MIGHT BE SHORT-LIVED AS YET ANOTHER SYSTEM
MAY BE ON THE HEELS OF THE RIDGE AND IMPACT US LATE SATURDAY INTO
SUNDAY.
AVIATION
(18Z TAF ISSUANCE)
ISSUED AT 1235 PM EST SUN DEC 4 2022
IMPACTS: POTENTIAL MVFR CIGS IN LIGHT RAIN DURING SDF PLANNING
PERIOD.
DISCUSSION: EXPANSIVE SURFACE HIGH PRESSURE EXISTS ACROSS THE OH
VALLEY TODAY AS HIGH CLOUDS STREAM OVERHEAD. LIGHT VARIABLE WINDS
WILL CONTINUE THIS AFTERNOON BEFORE TAKING ON A MORE PREDOMINATELY
SE DIRECTION OVERNIGHT AND INTO TOMORROW MORNING. CEILINGS WILL
BEGIN TO DROP BY TUESDAY LATE MORNING WITH A CHANCE OF LIGHT RAIN
ENTERING INTO BWG BY AS EARLY AS 05/15Z AND A FEW HOURS LATER AT THE
OTHER TAF SITES (HNB AND LEX PROBABLY AROUND 20Z, JUST OUTSIDE OF
THIS TAF CYCLE). CIGS WILL LIKELY DROP TO MVFR SHORTLY AFTER RAIN
BEGINS WITH IFR CIGS LIKELY TUESDAY NIGHT INTO WEDNESDAY MORNING.
CONFIDENCE: MEDIUM TO HIGH ON TIMING OF RAIN AND MVFR CIGS. HIGH ON
ALL OTHER FORECAST ELEMENTS.
LMK WATCHES/WARNINGS/ADVISORIES
IN...NONE.
KY...NONE.
SHORT TERM...CG
LONG TERM...DM
AVIATION...CG
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