555  
FXUS64 KLZK 201105 AAA  
AFDLZK  
 
AREA FORECAST DISCUSSION...UPDATED  
NATIONAL WEATHER SERVICE LITTLE ROCK AR  
605 AM CDT MON AUG 20 2018  
   
AVIATION
 
12Z FORECAST  
PREVAILING CONDITIONS WILL BE VFR, THOUGH THERE COULD BE SOME  
BRIEF MVFR RESTRICTION WITH SCATTERED SHOWERS/STORMS THAT DEVELOP.  
WINDS WILL INCREASE TO SUSTAINED SPEEDS AROUND 10 KNOTS, WITH  
HIGHER GUSTS AS A COLD FRONT MOVES THROUGH ARKANSAS TODAY AND  
TONIGHT.  

 
   
PREV DISCUSSION
 
(ISSUED 323 AM CDT MON AUG 20 2018)  
SHORT TERM...TODAY THROUGH TUESDAY NIGHT  
SURFACE MAP THIS MORNING SHOWS LOW PRESSURE OVER NORTHWEST  
MISSOURI, WITH A FRONTAL BOUNDARY EXTENDING FROM WESTERN MISSOURI  
INTO EASTERN OKLAHOMA. OUT AHEAD OF THAT ARE SEVERAL MESOSCALE  
BOUNDARIES LEFT OVER FROM OVERNIGHT STORMS.  
 
UPPER LOW CURRENTLY OVER EASTERN KANSAS/SOUTHERN NEBRASKA IS  
SHOWING UP WELL ON SATELLITE THIS MORNING. THIS WILL SEND AN  
ATTENDANT TROUGH THROUGH THE REGION LATER THIS MORNING, WITH THE  
SURFACE FRONT MOVING IN AS WELL.  
 
THE FAVORED REGION FOR SHOWERS AND THUNDERSTORMS TODAY WILL BE THE  
EASTERN HALF OR SOUTHEAST HALF OF ARKANSAS AS INSTABILITY WILL BE  
HIGHEST THERE, DAYTIME HEATING WILL BE MAXIMIZED, AND THE MOST  
SIGNIFICANT MOISTURE WILL BE POOLING AHEAD OF THE FRONT (DEWPOINTS  
75+). AS WAS THE CASE YESTERDAY EVENING AND INTO THE OVERNIGHT, A  
FEW SEVERE STORMS WILL BE POSSIBLE, WITH WINDS THE PRIMARY  
CONCERN. ALSO, WITH HIGH PRECIPITABLE WATER EXPECTED, AND THE  
TENDENCY OF STORMS TO FORM AND MOVE OVER THE SAME AREAS, HEAVY  
RAIN IS A POSSIBILITY.  
 
THE AFOREMENTIONED COLD FRONT SHOULD MOVE INTO EASTERN ARKANSAS  
LATE THIS AFTERNOON OR EARLY TONIGHT, WITH RAIN CHANCES WINDING  
DOWN AS COOLER AND DRIER AIR FOLLOWS.  
 
LONG TERM...WEDNESDAY THROUGH SUNDAY  
A RIDGE OF HIGH PRESSURE CENTERED OVER NORTHWEST TEXAS WILL KEEP  
NORTHWESTERLY FLOW OVER THE REGION THROUGH THE END OF THE WEEK. THIS  
WILL ALSO HELP TO KEEP TEMPERATURES REASONABLY COOL FOR LATE AUGUST.  
IN FACT, THURSDAY WILL BE OUR COOLEST DAY ACROSS ARKANSAS WITH HIGHS  
IN THE MID 70S TO UPPER 80S. A FEW AREAS COULD STILL TOUCH 90  
DEGREES ACROSS THE FAR SOUTH.  
 
THE GFS AND ECMWF DISAGREE SLIGHTLY ON PLACEMENT OF THE HIGH  
PRESSURE RIDGE, AS WELL AS AMPLIFICATION OF THE UPPER LEVEL FEATURE  
THROUGH THE WEEKEND. HOWEVER, THE MODELS REGAIN UNIFORMITY AS AN  
UPPER LEVEL SHORTWAVE PASSES ACROSS THE MIDWEST AND GREAT LAKES  
REGION ON FRIDAY. THIS WILL RETURN RAIN CHANCES TO THE WESTERN AND  
NORTHERN PORTIONS OF THE STATE THURSDAY AND FRIDAY. AT THIS TIME,  
HAVE ONLY INCLUDED SLIGHT CHANCES, AS THE BETTER FORCING WILL BE  
WELL NORTH OF THE STATE.  
 
MEANWHILE SURFACE WINDS WILL SHIFT TO A MORE SOUTHERLY DIRECTION,  
WHICH WILL HELP TO ADVECT MOISTURE BACK INTO THE REGION. THIS WILL  
GRADUALLY INCREASE TEMPERATURES AND RELATIVE HUMIDITY VALUES AS  
WELL. BY SATURDAY, HIGH TEMPERATURES WILL BE BACK IN THE UPPER 80S  
AND 90S STATEWIDE AND WILL REMAIN THAT WAY TROUGH MONDAY. HEAT INDEX  
VALUES COULD ALSO APPROACH OR EXCEED 100 DEGREES THIS WEEKEND,  
ALTHOUGH AT THIS TIME, EXPECT TO STAY BELOW HEAT ADVISORY CRITERIA.  
 
BY SUNDAY MORNING, THE AFOREMENTIONED RIDGE OF HIGH PRESSURE WILL  
BUILD AND ADVANCE EASTWARD, CENTERING OVER THE OKLAHOMA/ARKANSAS  
BORDER. THIS WILL WEAKEN THE FLOW ALOFT, BUT KEEP IT GENERALLY OUT  
OF THE NORTH.  
 
AT THE VERY END OF THE TERM, BOTH THE ECMWF AND GFS DEPICT A DIGGING  
UPPER LEVEL LOW ALONG THE PACIFIC NORTHWEST, WHICH SHOULD MOVE  
SOUTHEAST INTO THE FOUR CORNERS REGION. WHILE THIS FEATURE WON'T  
IMPACT ARKANSAS INITIALLY, IF THE SYSTEM HOLDS TOGETHER, IT COULD  
PROVIDE AN INTERESTING SCENARIO AS WE HEAD INTO SEPTEMBER.  
 
FIRE WEATHER...  
NO SIGNIFICANT FIRE WEATHER ISSUES ARE EXPECTED THROUGH THE NEXT  
SEVEN DAYS.  
 

 
   
LZK WATCHES/WARNINGS/ADVISORIES
 
NONE.  

 
 

 
 
AVIATION...57  
 
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