346  
FXUS63 KLMK 220703  
AFDLMK  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE LOUISVILLE KY  
303 AM EDT SUN OCT 22 2017  
   
SHORT TERM
 
(TODAY THROUGH MONDAY)  
ISSUED AT 255 AM EDT SUN OCT 22 2017  
 
HIGH PRESSURE CENTERED OVER THE MID-ATLANTIC REGION CONTINUED TO  
PROVIDE DRY WEATHER ACROSS THE LOWER OHIO VALLEY EARLY THIS MORNING  
AS THE LATEST SATELLITE IMAGERY SHOWS A STREAM OF CIRRUS MOVING  
OVERHEAD. THIS COMBINED WITH SOUTHEAST WINDS 5 TO 10 MPH HAS KEPT  
READINGS ELEVATED IN THE 50S TO LOWER 60S.  
 
FOR TODAY, PLAN ON ONE MORE SEASONABLY WARM DAY BEFORE UNSETTLED  
WEATHER AND LARGE TEMPERATURE CHANGES ARRIVE FOR MOST OF NEXT WEEK.  
A COLD FRONT, CURRENTLY ALONG A LINE FROM NEAR MINNEAPOLIS TO  
OKLAHOMA CITY WILL SLOWLY ADVANCE EASTWARD TOWARD OUR AREA TODAY.  
AHEAD OF THIS FRONT, A WELL MIXED BOUNDARY LAYER AND TIGHTENING  
PRESSURE GRADIENT WILL PROMOTE SOUTHERLY WIND GUSTS 20 TO 25 MPH AT  
TIMES. THIS WILL ALSO ALLOW TEMPERATURES TO RISE WELL INTO THE 70S,  
WITH A FEW LOCATIONS POSSIBLY HITTING THE 80 DEGREE MARK DESPITE  
SOME INCREASING HIGH CLOUDS.  
 
THE LATEST SUITE OF HI-RES MODELS CONTINUE TO SLOW THE PROGRESSION  
OF THE RAIN SHOWERS THIS AFTERNOON AND EVENING. THE BULK OF  
PRECIPITATION WILL LIKELY HOLD OFF UNTIL AFTER SUNSET, THOUGH A FEW  
SHOWERS MAY DEVELOP AHEAD OF THE MAIN LINE ACROSS SOUTHWEST INDIANA  
AND PORTIONS OF WEST CENTRAL KENTUCKY LATER THIS AFTERNOON.  
 
AS THE MAIN UPPER LEVEL ENERGY DROPS INTO ARKANSAS AND MISSISSIPPI  
TONIGHT, WIDESPREAD SHOWERS ARE EXPECTED TO LIFT INTO SOUTH CENTRAL  
KENTUCKY THEN SPREAD NORTHWARD THROUGH THE ENTIRE AREA OVERNIGHT  
INTO MONDAY MORNING. WILL MAINTAIN THE HIGHEST PRECIPITATION CHANCES  
FROM MID/LATE EVENING THROUGH MONDAY MORNING ACROSS THE ENTIRE AREA  
WHERE 1 TO 2 INCHES IS LIKELY. LOCALLY HIGHER AMOUNTS WILL BE  
POSSIBLE ACROSS SOUTH-CENTRAL KENTUCKY.  
 
THE ATMOSPHERE WILL BE CHARACTERIZED BY ANOMOUSOLY HIGH PWATS /1.5  
TO 1.7 INCHES/, STRONG MOISTURE TRANSPORT, AND DEEPLY SATURATED,  
WHICH ALL SUPPORT THE IDEA OF EFFICIENT RAIN PRODUCING SHOWERS. THIS  
COULD PRODUCE PERIODS OF HEAVY RAIN. THE ANTECEDENT DRY CONDITIONS  
WILL HELP AND WHILE LARGE SCALE FLOODING ISN'T A RISK, LOCALIZED  
SHORT TERM ISSUES COULD DEVELOP ACROSS CENTRAL KENTUCKY WHERE THE  
GREATEST RAINFALL RATES ARE LIKELY.  
 
THE UPPER SHORTWAVE AND SURFACE LOW WILL QUICKLY LIFT TO THE  
NORTHEAST OF THE AREA DURING THE DAY MONDAY, BRINGING A SOUTHWEST TO  
NORTHEAST END TO THE WIDESPREAD SHOWERS. IN ITS WAKE, A STRONG COLD  
FRONT WILL SWEEP THROUGH MONDAY EVENING AND MONDAY NIGHT, BRINGING A  
SURGE OF COLD AIR AND BREEZY NORTHWEST WINDS. PLAN ON LOWS MONDAY  
NIGHT IN THE 40S.  
 

 
   
LONG TERM
 
(MONDAY NIGHT THROUGH SATURDAY)  
ISSUED AT 256 AM EDT SUN OCT 22 2017  
 
THE TUESDAY THROUGH WEDNESDAY PERIOD WILL FEATURE WEATHER MORE LIKE  
NOVEMBER, NOT OCTOBER, WITH A LARGE UPPER LEVEL TROUGH ACROSS THE  
REGION BRINGING COOL TEMPERATURES AND CLOUDIER CONDITIONS. TUESDAY  
WILL BE A WINDY AND NOTICEABLY COLDER DAY WITH NORTHWEST WINDS  
GUSTING TO 20-30 MPH AT TIMES. THERE SHOULD BE PLENTY OF STRATO-CU  
DEVELOPMENT AND A CHANCE OF LIGHT RAIN SHOWERS OR SPRINKLES DURING  
THE DAY MAINLY ACROSS SOUTHERN INDIANA AND NORTHERN BLUEGRASS  
REGION. PLAN ON HIGHS TO STAY IN THE 50S.  
 
ON WEDNESDAY A QUICK MOVING NORTHWEST FLOW SYSTEM IS FORECAST TO  
DROP THROUGH THE UPPER MIDWEST INTO THE LOWER GREAT LAKES REGION.  
THE 22.00Z GUIDANCE POINTS TO THE MAJORITY OF ITS IMPACT CONFINED TO  
CENTRAL INDIANA AND CENTRAL OHIO, BUT WILL HAVE TO WATCH CLOSELY TO  
SEE IF IT BRUSHES PARTS OF SOUTHEAST INDIANA AND NORTHERN KENTUCKY  
WITH ANY SHOWERS. HIGHS ON WEDNESDAY WILL RANGE FROM THE LOW 50S  
ACROSS THE BLUEGRASS TO MID 50S CLOSER TO THE TN BORDER.  
 
DEPENDING ON TIMING AND HOW WINDS/CLOUDS MATERIALIZE, THURSDAY  
MORNING COULD BE ONE OF THE COOLEST MORNINGS SO FAR IN THE AUTUMN  
SEASON. A MODEL CONSENSUS PUTS LOWS IN THE MID TO UPPER 30S, WHICH  
COULD SUPPORT PATCHY FROST.  
 
BEYOND THURSDAY, FORECAST CONFIDENCE DROPS OFF CONSIDERABLY WITH THE  
POTENTIAL FOR ANOTHER WEATHER SYSTEM NEXT WEEKEND. THERE ARE PLENTY  
OF TIMING, THERMAL, AND SPATIAL DIFFERENCES IN THE 22.00Z GUIDANCE.  
FOR NOW, LEANED ON THE MODEL CONSENSUS WHICH ADVERTISES 20-40  
PERCENT RAIN CHANCES. TEMPERATURES COULD BE SEASONABLY COLD IN THE  
WAKE OF THAT SYSTEM BUT FOR NOW WILL SHOW HIGHS IN THE 50S AND LOWS  
IN THE 30S.  
 

 
   
AVIATION
 
(06Z TAF ISSUANCE)  
ISSUED AT 1245 AM EDT SUN OCT 22 2017  
 
PREVAILING VFR CONDITIONS EXPECTED THROUGH THE VALID TAF PERIOD.  
MAIN OVERNIGHT CHALLENGE IS WIND SHEAR, AS LOW-LEVEL JETTING WILL  
START TO PICK UP. WILL INITIALIZE BWG AND HNB WITH 35 KT AT 2000  
FEET, AND SPREAD THAT INTO SDF FOR THE PRE-DAWN HOURS. THOSE WINDS  
START TO MIX DOWN SHORTLY AFTER DAYBREAK, WITH 20-25 KT SFC WIND  
GUSTS LIKELY SUNDAY AFTERNOON.  
 
NEXT QUESTION IS THE TIMING OF PRECIP AS A COLD FRONT MAKES SLOW  
PROGRESS INTO THE OHIO VALLEY. WILL BRING AT LEAST PROB30 OR VCSH  
INTO HNB IN THE AFTERNOON, WITH PREVAILING SHRA AND MVFR CONDITIONS  
IN THE EVENING. SDF AND BWG WON'T SEE PRECIP UNTIL AFTER 00Z, AND  
NOT EXPECTING SIGNIFICANT CIG/VIS RESTRICTIONS AS DRIER AIR WILL  
TAKE SOME TIME TO OVERCOME. WILL KEEP LEX DRY AND VFR THROUGH 06Z.  
 

 
   
LMK WATCHES/WARNINGS/ADVISORIES
 
 
IN...NONE.  
KY...NONE.  

 
 

 
 
SHORT TERM...ZT  
LONG TERM...ZT  
AVIATION...RAS  
 
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