993  
FXUS63 KPAH 200447  
AFDPAH  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE PADUCAH KY  
1147 PM CDT TUE MAR 19 2019  
   
UPDATE
 
 
ISSUED AT 1147 PM CDT TUE MAR 19 2019  
 
THE AVIATION SECTION HAS BEEN UPDATED FOR THE 06Z TAF ISSUANCE.  
 

 
   
SHORT TERM
 
(TONIGHT THROUGH THURSDAY NIGHT)  
ISSUED AT 325 PM CDT TUE MAR 19 2019  
 
SURFACE HIGH PRESSURE WILL CONTINUE TO RETREAT TO THE EAST OF THE  
WFO PAH FORECAST AREA THIS AFTERNOON AND THIS EVENING IN ADVANCE  
OF SHORTWAVE/CLOSED LOW OVER CENTRAL AND EASTERN NEBRASKA. THE  
SHORTWAVE WITH AN EMBEDDED LOW WILL SLOWLY ROTATE SOUTHEAST  
THROUGH KANSAS AND MISSOURI TONIGHT AND WEDNESDAY, REACHING INTO  
SOUTHEAST MISSOURI LATE AFTERNOON ON WEDNESDAY. A PRE-FRONTAL  
TROUGH AXIS WILL DEVELOP DURING THE DAY, WORKING NORTHWEST TO  
SOUTHEAST THROUGH THE AREA. THE AGEOSTROPHIC FORCING WILL LIKELY  
GENERATE SOME PARCEL TRANSFER IN THE BOUNDARY LAYER, PRODUCING  
SOME GUSTY SOUTHWEST WINDS FROM LATE MORNING AND THROUGH THE  
AFTERNOON. IN THE ABSENCE OF DEEP LAYER MOISTURE, ANTICIPATE JUST  
LIGHT RAIN AMOUNTS FROM DAYBREAK WEDNESDAY THROUGH EARLY WEDNESDAY  
EVENING ACROSS THE WFO PAH FORECAST AREA. PRECIPITATION AMOUNTS  
(QPF) SHOULD REMAIN BETWEEN A TRACE AND 0.20 OF AN INCH FOR  
RAINFALL TOTALS FOR THE EVENT.  
 
AS THE SHORTWAVE AND TROUGH EXIT THE WFO PAH FORECAST AREA BY  
MIDNIGHT WEDNESDAY NIGHT, THE LEADING EDGE OF A SURFACE TO UPPER  
LEVEL RIDGE WILL PUSH ACROSS THE AREA THURSDAY AND THURSDAY NIGHT.  
 
WITH INCREASE SOUTHERLY FLOW TONIGHT INTO WEDNESDAY, ANTICIPATE  
TEMPERATURES REMAINING SOME 5 TO 7 DEGREES ABOVE THIS MORNING'S  
LOW TEMPERATURES, WITH HIGHS ON WEDNESDAY AT OR SLIGHTLY HIGHER  
THAN TODAY, EVEN WITH CLOUD COVER AND INCREASING RAIN CHANCES.  
TEMPERATURES ON THURSDAY AND THURSDAY NIGHT WILL DROP BACK ONLY A  
FEW DEGREES AS THICKNESSES INCREASE IN THE WAKE OF THE DEPARTING  
TROUGH, BALANCING WITH RADIATIONAL LOSS IN TEMPERATURES THURSDAY  
NIGHT.  
   
LONG TERM
 
(FRIDAY THROUGH TUESDAY)  
ISSUED AT 325 PM CDT TUE MAR 19 2019  
 
RIDGING WILL CONTINUE TO DOMINATE THE WFO PAH FORECAST AREA  
THROUGH SATURDAY. PREVIOUS (FROM THIS PAST WEEKEND) AND CURRENT  
MEDIUM RANGE NUMERICAL MODEL TRENDS HAVE BEEN SHOWING THAT THE  
RIDGE WOULD REMAIN DOMINATE THROUGH SATURDAY, MOVING EAST SATURDAY  
NIGHT. THE NORTHWARD MOISTURE TRAJECTORY FROM THE WESTERN GULF OF  
MEXICO CONTINUES TO REMAIN PERSISTENT FROM RUN TO RUN IN THE  
MEDIUM RANGE MODEL SUITE, FOCUSING MOST OF THE RAIN IN A  
NORTH/SOUTH CORRIDOR, BALANCES BY THERMAL INSTABILITY DUE TO THE  
MOISTURE FROM THE SOUTH AND THE DYNAMIC INSTABILITY ASSOCIATED  
WITH THE NEXT SERIES OF SHORTWAVES AMPLIFYING THE QUASI-ZONAL FLOW  
OVER THE NORTHWEST QUARTER OF THE NATION ON SUNDAY INTO MONDAY.  
THERE IS HIGH CONFIDENCE OF THE RAIN CHANCES ASSOCIATED WITH THE  
SYSTEM MOVING ACROSS SUNDAY AND MONDAY, BUT THE MECHANISM OF LIFT  
IS SOMEWHAT UNCERTAIN, DEPENDING ON THE MODEL GUIDANCE YOU PREFER.  
WITH THAT IN MIND, HAVE LOW FORECAST CONFIDENCE ON TUESDAY AND  
TUESDAY NIGHT ON THE COVERAGE AND TYPE OF PRECIPITATION. THE GFS  
DETERMINISTIC SOLUTION FAVORS A MORE DISTINCT AND PROGRESSIVE  
SHORT WAVELENGTH TROUGH-RIDGE-TROUGH PATTERN EARLY NEXT WEEK,  
WHILE THE ECMWF DEPICTS AN EXITING EASTERN U.S. TROUGH AND AND  
APPROACHING SPLIT FLOW WITH A NORTHERN RIDGE/SOUTHERN TROUGH  
ENVELOPING THE WFO PAH FORECAST AREA ON TUESDAY.  
 
THE INSTABILITY FORECAST (FOR THUNDERSTORM MENTION) MAY CHANGE  
MARKEDLY SUNDAY INTO MONDAY FOR THE NEXT FEW FORECAST CYCLES UNTIL  
THE ORIENTATION AND PLACEMENT OF SHORTWAVE TRANSVERSING ACROSS THE  
AREA BECOMES MORE WELL DEFINED. GIVEN THE POTENTIAL MESOSCALE  
NATURE OF THE SHORTWAVE, ANY DEFINED THUNDERSTORM COVERAGE MAY NOT  
COME INTO MORE DISTINCT VIEW UNTIL THE FRIDAY FORECAST PACKAGE.  
 
FROM A SENSIBLE WEATHER PERSPECTIVE, THERE IS HIGH FORECAST  
CONFIDENCE FOR RAIN SUNDAY INTO MONDAY AND LESS CONFIDENCE TUESDAY  
AND BEYOND.  
 

 
   
AVIATION
 
 
ISSUED AT 1147 PM CDT TUE MAR 19 2019  
 
COMPLEX UPPER PATTERN THROUGH THE PERIOD, WITH A PAIR OF MINOR  
IMPULSES BRINGING SOME LIGHT SHOWERS TO THE REGION THROUGH THE  
DAY, AND THEN A LARGER-SCALE UPPER TROUGH BRINGING MORE PROLONGED  
RAINS TO SOUTHWEST INDIANA AND WEST KENTUCKY THROUGH THE EVENING.  
THERE IS NO WELL-DEFINED SURFACE BOUNDARY, SO LEANED TOWARD THE  
OPTIMISTIC SIDE OF GUIDANCE AND KEPT CONDITIONS IN THE UPPER HALF  
OF MVFR AT ALL SITES IN THE RAIN. SOME GUIDANCE SUPPORTS IFR  
CEILINGS IN THE RAIN IN THE LATE AFTERNOON AND EVENING, SO  
ADJUSTMENTS LOWER MAY BE NECESSARY WITH SUBSEQUENT FORECASTS.  
 

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

 
 

 
 
UPDATE...DRS  
SHORT TERM...SMITH  
LONG TERM...SMITH  
AVIATION...DRS  
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab KY Page
The Nexlab IL Page
The Nexlab IN Page
The Nexlab MO Page Main Text Page