087  
FXUS63 KLMK 181723  
AFDLMK  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE LOUISVILLE KY  
1223 PM EST WED JAN 18 2017  
   
..UPDATED AVIATION DISCUSSION
 
 
   
FORECAST UPDATE
 
 
ISSUED AT 1115 AM EST WED JAN 18 2017  
 
LOW STRATUS REMAINS ENTRENCHED ACROSS THE REGION THIS MORNING.  
TEMPERATURES GENERALLY WERE IN THE LOWER TO MIDDLE 40S. SOME BREAKS  
IN THE CLOUDS WERE NOTED ACROSS SOUTH-CENTRAL KY DOWN TOWARD THE  
LAKE CUMBERLAND REGION. OVERALL, THE MODEL GUIDANCE IS FAIRLY GOOD  
AGREEMENT WITH KEEPING THINGS MOSTLY CLOUDY THROUGHOUT THE REST OF  
THE DAY. THIS IDEA HAS SUPPORT BASED ON THE LATEST SATELLITE DATA.  
FOR NOW, HAVE ADJUSTED THE CLOUD COVER UP A BIT IN THE FORECAST AND  
LOWERED DAYTIME HIGHS SLIGHTLY. HIGHS OF 40-45 ARE MORE LIKELY  
ACROSS SOUTHERN IN AND NORTHERN KY WITH 45-50 IN AREAS SOUTH OF THE  
WK AND BG PARKWAYS.  
 

 
   
SHORT TERM (NOW THROUGH THURSDAY)
 
 
ISSUED AT 245 AM EST WED JAN 18 2017  
 
A SURFACE ANALYSIS EARLY THIS MORNING HAD HIGH PRESSURE CENTERED  
OVER MISSOURI WHILE YESTERDAY'S COLD FRONT NOW WAS ALONG THE  
APPALACHIANS OF NC/VA/WV. ALOFT, WATER VAPOR IMAGERY SHOWED A TIGHT,  
QUICK MOVING SHORTWAVE DROPPING THROUGH INDIANA AND OHIO, WHILE  
SATELLITE IMAGERY SHOWED PLENTY OF STRATUS ACROSS THE LOWER OHIO  
VALLEY AND BACK UPSTREAM TOWARD THE UPPER MIDWEST. LOCALLY, READINGS  
WERE IN THE UPPER 30S TO MIDDLE 40S.  
 
THE MAIN FORECAST CHALLENGE FOR TODAY IS SKY COVER. THE 00Z ILX  
SOUNDING AND CURRENT HRRR/RAP SOUNDINGS SHOW THIS MOISTURE IS  
TRAPPED WITHIN A 850-900 MB INVERSION. FORECAST SOUNDINGS THROUGH  
THE DAY SHOW SOME DRY AIR WORKING DOWN ON THIS LAYER ALONG WITH SOME  
MIXING THROUGHOUT THE DAY BUT WITH SLOW PROGRESS. EXPECT OVERCAST  
SKIES THIS MORNING AND INTO THE FIRST PART OF THE AFTERNOON, BUT  
SOME BREAKS AND PEAK OF SUN BY LATE AFTERNOON ARE EXPECTED. HIGHS  
MAINLY IN THE MIDDLE 40S TO LOWER 50S.  
 
THE FIRST IN A SERIES OF SOUTHERN STREAM IMPULSES ARRIVES LATE  
TONIGHT THROUGH THURSDAY AS A CLOSED UPPER LOW TAKES SHAPE OVER THE  
CENTRAL PLAINS. THIS WILL OPEN UP THE GULF WITH A GOOD AMOUNT OF  
MOISTURE SURGING NORTHWARD. PWATS WILL CLIMB TO 1.3 INCHES, OR  
ROUGHLY 3 STANDARD DEVIATIONS ABOVE NORMAL FOR THURSDAY,SUGGESTING  
THE POTENTIAL FOR SOME LOCALLY HEAVY RAIN PRODUCING SHOWERS. WITH  
GOOD ISENTROPIC LIFT AND MOISTURE TRANSPORT, SHOWERS ARE EXPECTED TO  
BREAK OUT EARLY THURSDAY MORNING ACROSS SOUTHWEST AND SOUTH-CENTRAL  
KY THEN MOVE NORTH/NORTHEAST THROUGH THE DAY. GIVEN THE HIGH  
AGREEMENT AND CONSISTENCY IN THE LATEST FORECAST MODELS,  
PRECIPITATION CHANCES WERE BROUGHT UP INTO THE 70-90 PERCENT RANGE  
FOR THURSDAY, ESPECIALLY IN THE AFTERNOON HOURS. SOME WEAK ELEVATED  
INSTABILITY MAY BRING A FEW RUMBLES OF THUNDER AS WELL, MAINLY  
ALONG/SOUTH OF THE OHIO RIVER THURSDAY AFTERNOON. THE RECENT STRETCH  
OF RAIN AND SATURATED SOILS MAY RESULT IN LOCALIZED LOW-LYING  
FLOODING ISSUES, AND RISES ON STREAMS AND CREEKS.  
   
LONG TERM (THURSDAY NIGHT THROUGH TUESDAY)
 
 
ISSUED AT 300 AM EST WED JAN 18 2017  
 
...ABOVE NORMAL TEMPERATURES AND FREQUENT ROUNDS OF RAIN DURING  
EXTENDED PERIOD...  
 
THURSDAY NIGHT - FRIDAY NIGHT...  
 
THE LATEST MEDIUM RANGE GUIDANCE CONTINUES TO SUGGEST MULTIPLE  
ROUNDS OF SIGNIFICANT RAINFALL IN A VERY MERIDIONAL LONGWAVE  
PATTERN. THE FIRST EVENT WILL BE WELL UNDERWAY BY THURSDAY EVENING.  
A CLOSED UPPER LOW WILL MOVE INTO THE MIDWEST REGION AND SWING A  
NEGATIVELY TITLED TROUGH INTO THE OHIO VALLEY THURSDAY NIGHT. THIS  
PVA REGIME WILL PROMOTE EXCELLENT LIFT ACROSS THE AREA OVERNIGHT.  
WITH RIDGING CENTERED OVER THE ATLANTIC COAST, DEEP SOUTHERLY FLOW  
WILL PUMP IN COPIOUS AMOUNTS OF MOISTURE FOR THIS TIME OF YEAR. THE  
LATEST GFS FEATURES MAX PRECIPITABLE WATER VALUES AROUND 1.3 INCHES  
00-06Z FRIDAY. THE NAEFS INDICATES PWATS RUNNING BETWEEN 2-3  
STANDARD DEVIATIONS ABOVE CLIMATOLOGY. SO EXPECT ANOTHER NICE SLUG  
OF RAIN THURSDAY NIGHT WITH LOWS ONLY IN THE UPPER 40S TO MID 50S.  
GIVEN RECENT RAINFALL AND FAIRLY SATURATED SOILS, MINOR FLOODING  
ISSUES MAY BECOME MORE COMMON LATE THIS WEEK.  
 
RAIN CHANCES DIMINISH FROM WEST TO EAST FRIDAY MORNING. WEAK RIDGING  
BUILDS THROUGH THE OHIO VALLEY ON FRIDAY. DRY WEATHER WILL PERSIST  
THROUGH FRIDAY NIGHT WITH CENTRAL KENTUCKY AND SOUTHERN INDIANA IN  
BETWEEN WEATHER SYSTEMS. FRIDAY LOOKS QUITE WARM, WITH HIGHS WELL  
INTO THE 60S.  
 
SATURDAY - TUESDAY...  
 
SATURDAY LOOKS A BIT WARMER STILL WITH SOUTHERLY FLOW OUT AHEAD OF  
YET ANOTHER STORM SYSTEM IN THE PLAINS. HIGHS WILL LIKELY REACH THE  
MID TO UPPER 60S, AND 70 DEGREES IS A POSSIBILITY. RAIN CHANCES  
START TO INCREASE DURING THE LATTER HALF OF SATURDAY AS LOW PRESSURE  
DEEPENS IN THE SOUTHERN PLAINS. THE GFS AND ECMWF HAVE ACTUALLY BEEN  
PRETTY CONSISTENT FORECASTING A MID-LEVEL WAVE WRAPPING UP INTO A  
CLOSED LOW ACROSS THE SOUTHEAST U.S. SATURDAY NIGHT THROUGH SUNDAY  
NIGHT. MULTIPLE ROUNDS OF RAIN APPEAR LIKELY, AND THE RAIN MAY BE  
HEAVY AT TIMES. THERE IS A DECENT CHANCE FOR THUNDERSTORMS ON SUNDAY  
AS THE PRIMARY LOW MOVES INTO THE REGION. PWAT VALUES ONCE AGAIN  
EXCEED 1 INCH BY SUNDAY EVENING. RAIN CHANCES FINALLY DIMINISH  
MONDAY NIGHT, AND TUESDAY LOOKS DRY.  
 
SOMEWHAT COOLER AIR WILL WORK BACK INTO CENTRAL KENTUCKY AND  
SOUTHERN INDIANA EARLY NEXT WEEK WITH HIGHS IN THE 50S.  
 

 
   
AVIATION
 
(18Z TAF ISSUANCE)  
ISSUED AT 1220 PM EST WED JAN 18 2017  
 
MVFR STRATUS DECK STICKING AROUND A FEW MORE HOURS, AND ARE CLOSE  
ENOUGH AT LEX TO IFR LEVELS TO HAVE A THREAT THERE FOR AT LEAST  
ANOTHER HOUR. STILL EXPECT THE STRATUS TO ERODE AS THE LAYER OF  
CLOUDS ARE FAIRLY THIN. BY EARLY EVENING, ALL SITES SHOULD BE VFR.  
AFTER A BRIEF SHOT AT FOG AT LEX TOWARD DAYBREAK THURSDAY, THE NEXT  
ISSUE WILL BE A STORM SYSTEM BRINGING RAIN CHANCES AND LOWER CIGS BY  
LATE MORNING AT BWG AND THEN AFTERNOON AT SDF.  
 

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

 
 

 
 
UPDATE...MJ  
SHORT TERM...ZT  
LONG TERM...EBW  
AVIATION...RJS  
 
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