868  
FXUS63 KPAH 181137  
AFDPAH  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE PADUCAH KY  
537 AM CST FRI JAN 18 2019  
   
UPDATE
 
 
ISSUED AT 530 AM CST FRI JAN 18 2019  
 
FOR AVIATION SECTION ONLY.  
 

 
   
SHORT TERM
 
(TODAY THROUGH SUNDAY NIGHT)  
ISSUED AT 338 AM CST FRI JAN 18 2019  
 
MAIN FORECAST CHALLENGES/CONCERNS IN THE SHORT TERM CONTINUES TO  
LIE WITH THE STORM SYSTEM EXPECTED TO AFFECT MUCH OF THE REGION  
TONIGHT THROUGH SATURDAY EVENING.  
 
IMPORTANT NOTE: THERE IS STILL A CONSIDERABLE AMOUNT OF MODEL  
UNCERTAINTY IN REGARDS TO THE WINTER ASPECT OF THIS SYSTEM  
SATURDAY AFTERNOON AND EVENING. CONFIDENCE REMAINS LOW AT THIS  
TIME, ESPECIALLY IN LOCATIONS ALONG AND SOUTH OF THE OHIO RIVER.  
 
WIDESPREAD MODERATE TO OCCASIONALLY HEAVY RAINS, AND EVEN A FEW  
ISOLATED THUNDERSTORMS (SOUTH AREAS), WILL SPREAD EAST ACROSS THE  
FORECAST AREA TONIGHT AS STRONG MID LEVEL FORCING GETS UNDERWAY  
AHEAD OF A POTENT MID LEVEL TROF MOVING EAST THROUGH THE SOUTHERN  
PLAINS/AR REGION. GENERAL RAINFALL AMOUNTS CLOSE TO AN INCH TO AN  
INCH AND A HALF ARE EXPECTED THROUGH SATURDAY, HIGHEST NUMBERS  
OVER WRN KY. WITH THE GROUND ALREADY QUITE WET, WE COULD SEE SOME  
MINOR FLOODING IMPACTS TO CREEKS, STREAMS AND CLOGGED DRAINAGES,  
ESPECIALLY WHERE THE RAIN COMES DOWN HARD AT TIMES. HOWEVER,  
WIDESPREAD FLOODING IS NOT EXPECTED TO POSE AN ISSUE, SO WILL HOLD  
OFF ON ANY HEADLINES AT THIS TIME.  
 
BIGGER QUESTIONS AND UNCERTAINTY COME INTO PLAY SATURDAY AFTERNOON  
AND SATURDAY NIGHT AS THE ASSOCIATED SURFACE LOW MOVES EAST  
THROUGH THE MID MS RIVER VALLEY. THOUGH MOST MODELS HAVE COME INTO  
AGREEMENT NOW ON A SURFACE LOW TRACK THROUGH WRN KY ON SAT, THERE  
ARE STILL DIFFERENCES ON HOW THEY HANDLE THE MID/UPPER LEVEL  
DYNAMICS AS NORTHERN AND SOUTHERN BRANCH TROFS INTERACT AND TRY TO  
POSSIBLY PHASE.  
 
FOR NOW, IT LOOKS AS THROUGH THERE IS DECENT CONSENSUS THAT AT  
LEAST SOME TYPE OF DEFORMATION ZONE WILL SET UP FOR A FEW HOURS  
AS MUCH COLDER AIR SWEEPS SOUTHEAST INTO THE REGION SATURDAY  
AFTERNOON AND EARLY EVENING. IF THIS SCENARIO INDEED OCCURS, WE  
WOULD HAVE THE POTENTIAL FOR A COUPLE INCHES OF SNOW ACROSS ABOUT  
THE NORTHERN HALF OF THE FORECAST AREA. GENERALLY LESS THAN AN  
INCH WOULD BE POSSIBLE FARTHER SOUTH OVER SOUTHERN PORTIONS OF  
WESTERN KY AND MO. HOWEVER, WITH RAPIDLY FALLING TEMPERATURES  
INTO THE 20S AND BLUSTERY NORTH WINDS HOWLING OVER 30 MPH, EVEN  
SMALL AMOUNTS OF ACCUMULATING SNOW COULD CAUSE SOME TRAVEL  
IMPACTS. GIVEN EXISTING UNCERTAINTY AND THE FACT THAT THE MAIN  
WINTER IMPACTS ARE NOT ANTICIPATED UNTIL LATER IN THE 3RD PERIOD  
OF THE FORECAST, WILL HOLD OFF ON HEADLINES WITH THIS PACKAGE AND  
LET THE DAY SHIFT TAKE ANOTHER LOOK AND HONE IT A BIT BETTER. IT  
IS STILL A SOMEWHAT FLUID SITUATION GIVEN THE COMPLEXITY OF THE  
MID/UPPER LEVEL DYNAMICS. WILL ISSUE A STRONGLY WORDED SPECIAL  
WEATHER STATEMENT WITH THIS FORECAST PACKAGE.  
 
CONDITIONS WILL BECOME QUITE BLUSTERY AND COLD SATURDAY NIGHT AS  
THE LOW PULLS OFF TO THE EAST, WITH TEMPS TUMBLING INTO THE MID  
TEENS TO NEAR 20. WIND CHILLS WILL LIKELY DIP INTO THE SINGLE  
DIGITS AT MOST LOCATIONS BY SUNRISE SUNDAY. AS THE BULK OF THE  
COLD AIR ARRIVES IN FORCE SUNDAY, HIGH TEMPS AT MOST LOCATIONS  
WILL NOT GET OUT OF THE 20S. IT COULD EVEN STAY IN THE TEENS TO  
NEAR 20 UP ALONG THE I-64 CORRIDOR IF THERE IS A DECENT COATING OF  
SNOW ON THE GROUND. SUNDAY NIGHT APPEARS IT WILL BE THE COLDEST  
NIGHT WITH THIS OUTBREAK AS THE SURFACE HIGH MOVES EAST OVER THE  
GREAT LAKES REGION. MOST LOCATIONS WILL FALL WELL INTO THE TEENS  
BY SUNRISE MONDAY.  
   
LONG TERM
 
(MONDAY THROUGH THURSDAY)  
ISSUED AT 338 AM CST FRI JAN 18 2019  
 
CONFIDENCE IN THE LONG TERM PORTION OF THE FORECAST STARTS OFF  
HIGHER THAN AVERAGE WITH GOOD OVERALL MODEL AGREEMENT AT THE START  
OF NEXT WEEK. HOWEVER, CONFIDENCE DROPS OFF BY MID WEEK WITH GREATER  
MODEL VARIABILITY OVER THE TIMING OF THE NEXT WEATHER SYSTEM.  
 
THE CORE OF ARCTIC HIGH PRESSURE WILL SHIFT TO THE EAST BY MONDAY AS  
OUR NEXT STORM SYSTEM APPROACHES FROM THE CENTRAL PLAINS. FLATTENING  
FLOW ALOFT AND LOW LEVEL SOUTHERLIES SHOULD BRING ABOUT A DECENT  
MODERATING TREND, WITH HIGHS ON MONDAY FORECAST BACK INTO THE 30S.  
THE CHANCE FOR PRECIPITATION WILL INCREASE LATE MONDAY NIGHT INTO  
TUESDAY AS THE PLAINS SYSTEM APPROACHES AND MAKES PASSAGE. THE BULK  
OF AVAILABLE GUIDANCE INDICATES A THERMAL PROFILE WARM ENOUGH TO  
SUPPORT MAINLY RAIN DURING THIS TIME. ENOUGH COLD AIR MAY WORK IN ON  
THE BACK EDGE OF THE PRECIPITATION SHIELD TO RESULT IN A TRANSITION  
TO A PERIOD OF SNOW OR A MIX BEFORE ENDING SOMETIME MID WEEK.  
 
THE FORECAST FROM WEDNESDAY ON IS REALLY SUBJECT TO CHANGE AT THIS  
POINT. THE MODEL BLEND HANGS ON TO A SMALL CHANCE OF SNOW THROUGH  
WEDNESDAY NIGHT AND THURSDAY MORNING. OF THE 00Z RUNS, THE CMC IS  
THE ONLY MODEL THAT SUPPORTS THIS, AS WAS THE CASE WITH ITS 12Z  
PREDECESSOR, PRIMARILY DUE TO ITS SLOWER/FURTHER WEST PROGRESSION OF  
A SECONDARY SOUTHERN STREAM WAVE. PRIOR TO THAT, THE ECMWF HAD BEEN  
THE SLOW OUTLIER. WITHIN THE 00Z GEFS, A QUARTER OF THE ENSEMBLE  
MEMBERS SUPPORT A SECONDARY ROUND OF WINTRY PRECIPITATION WEDNESDAY  
INTO EARLY THURSDAY. SO WHILE PROLONGING PRECIPITATION CHANCES IS  
NOT NECESSARILY THE FAVORED SOLUTION AT THIS TIME, IT CANNOT BE  
COMPLETELY RULED OUT. THUS, WILL MAINTAIN THE LOW CHANCES IN THE  
INITIALIZED BLEND FOR THE TIME BEING UNTIL CONFIDENCE IMPROVES.  
 

 
   
AVIATION
 
 
ISSUED AT 536 AM CST FRI JAN 18 2019  
 
EXPECT LOW END MVFR CIGS 1-2 KFT TO PERSIST MUCH OF THE FORECAST  
PERIOD, THO THESE CIGS ARE ALIKE TO DETERIORATE TO BLO 1 KFT FROM  
WEST TO EAST LATE TONIGHT 05-10Z SAT AS RAIN ARRIVES AHEAD OF THE  
NEXT WEATHER SYSTEM. WINDS WILL LIGHT.  
 

 
   
PAH WATCHES/WARNINGS/ADVISORIES
 
 
IL...NONE.  
MO...NONE.  
IN...NONE.  
KY...NONE.  

 
 

 
 
UPDATE...GM  
SHORT TERM...GM  
LONG TERM...RJP  
 
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