495  
FXUS63 KABR 231612 CCA  
AFDABR  
 
AREA FORECAST DISCUSSION...CORRECTED  
NATIONAL WEATHER SERVICE ABERDEEN SD  
1112 AM CDT SAT JUN 23 2018  
   
UPDATE
 
 
ISSUED AT 1105 AM CDT SAT JUN 23 2018  
 
UPPER LOW PRESSURE AREA SPINNING OVER CENTRAL SD THIS MORNING WILL  
MAKE ITS WAY SLOWLY EAST AND NORTHEAST INTO THIS EVENING. SHOWERS  
AND THUNDERSTORMS HAVE BEEN OCCURRING ALL MORNING NEAR THIS UPPER  
LOW PRESSURE AREA WITH SOME RADAR ESTIMATES UP TO 2 INCHES IN  
NORTHERN POTTER COUNTY. WITH THE LIFT FROM THIS UPPER LOW PRESSURE  
AREA ALONG WITH LITTLE TO NO CAP AND INCREASING INSTABILITY WITH  
SURFACE HEATING, EXPECT THE COVERAGE OF SHOWERS AND STORMS TO  
INCREASE QUITE A BIT INTO THE AFTERNOON. ALREADY HAVE IN LIKELY  
POPS AND IT LOOKS GOOD. THE SHOWERS AND CLOUD COVER WILL ALSO HOLD  
TEMPERATURES DOWN SOME. STILL EXPECT HIGHS TO BE MOSTLY IN THE  
UPPER 70S AND LOWER 80S. UPDATED FORECAST.  
 
UPDATE ISSUED AT 636 AM CDT SAT JUN 23 2018  
 
AVIATION DISCUSSION UPDATED BELOW FOR 12Z TAFS.  
 

 
   
SHORT TERM
 
(TODAY AND TONIGHT)  
ISSUED AT 402 AM CDT SAT JUN 23 2018  
 
SATELLITE/RADAR IMAGERY CLEARLY SHOWS A VORT MAXIMA MOVING NORTHWARD  
ACROSS NORTH CENTRAL SD INTO SOUTH CENTRAL ND, WITH SCATTERED SHOWER  
AND THUNDERSTORM ACTIVITY ASSOCIATED WITH IT. THE SURFACE TROUGH IS  
BACK OVER WESTERN SD AT THIS TIME. AS THE DAY PROGRESSES, THE  
SURFACE TROUGH WILL ADVANCE EASTWARD AND APPROACH THE JAMES RIVER BY  
LATE AFTERNOON. ALL MODELS AGREE FAIRLY WELL IN ADDITIONAL SHOWER  
AND THUNDERSTORM DEVELOPMENT BY MID TO LATE AFTERNOON IN AND AROUND  
THE JAMES RIVER VALLEY, WITH VARYING DEGREES OF AREAL COVERAGE.  
ALTHOUGH, IT APPEARS MORE PLACES WILL GET WET THAN NOT SO WILL  
CONTINUE WITH THE FAIRLY HIGH PRECIP CHANCES. WITH BROAD UPPER LEVEL  
LOW PRESSURE OVER THE REGION AND A HANDFUL OF SHORTWAVES ROTATING  
ACROSS THE DAKOTAS, WILL LIKELY SEE SCATTERED ACTIVITY ACROSS OTHER  
PORTIONS OF THE CWA AS WELL. A RIBBON OF INSTABILITY DOES SET UP  
ACROSS THE JAMES VALLEY THIS AFTERNOON WITH CAPE VALUES OVER 1000  
J/KG. BULK SHEAR IS LACKING, ALTHOUGH 0-1KM SHEAR IS AROUND 10 TO 20  
KNOTS. CAM SOLUTIONS SHOW SCATTERED THUNDERSTORMS DEVELOPING BY MID  
TO LATE AFTERNOON, AND WOULD NOT BE SURPRISED IF WE SEE A  
LANDSPOUT/WEAK TORNADO SOMEWHERE ACROSS THE CWA GIVEN THE BIT OF LOW-  
LEVEL WIND SHEAR ALIGNING WITH A SURFACE VORTICITY MAXIMA WITHIN THE  
TROUGH AXIS. DON'T EXPECT SUPERCELL TYPE STRUCTURED STORMS TODAY  
GIVEN THE LACK OF OVERALL BULK SHEAR VALUES.  
 
HIGH TEMPS TODAY ARE A BIT TRICKY SINCE WE WILL BE DEALING WITH  
PERIODS OF CLOUDINESS ALONG WITH PEEKS OF SUNSHINE HERE AND THERE. A  
BIT HARD TO DETERMINE OVERALL RESIDENCE TIME OF CLOUDS IN PLACES TO  
DETERMINE HIGHS. PLUS, AFTERNOON DEVELOPMENT OF PRECIPITATION WOULD  
PUT A HOLD ON TEMP CLIMBS. THAT SAID, DID FAVOR WARMER GUIDANCE,  
ESPECIALLY IN RECENT WARM SPOTS SUCH AS ABERDEEN. ALTHOUGH AGAIN,  
ANY ABUNDANCE OF MID-LEVEL CLOUDS AND/OR PRECIPITATION WOULD CAUSE  
HIGHS TO FALL A BIT SHORT OF FORECAST. DID INCREASE TEMPS A BIT OVER  
THE SOUTHWEST CWA AS GOOD WEST-NORTHWEST MIXING WINDS DEVELOP BEHIND  
THE SURFACE TROUGH THIS AFTERNOON AS WARMING 850MB TEMPS MOVE IN.  
   
LONG TERM
 
(SUNDAY THROUGH FRIDAY)  
ISSUED AT 402 AM CDT SAT JUN 23 2018  
 
WE HAVE THE INITIAL WAVE TODAY IN THE SHORT TERM, WHICH IS FOLLOWED  
UP WITH A SECOND SYSTEM COMING OUT OF THE ROCKIES EARLY SUNDAY,  
EJECTING A WEAK 500MB WAVE AHEAD OF THE MAIN UPPER TROUGH, THOUGH  
THERE IS LITTLE REFLECTION OTHER THAN SOME WEAK WARM ADVECTION IN  
THE MID LEVELS. LCLS REMAIN LOW, BETWEEN 1 AND 2KFT, AND PROFILES  
ARE MOIST ADIABATIC(MLCAPE ONLY ABOUT 500-1500J/KG) WITH GENERALLY  
WEAK SHEAR. THUS, ANTICIPATED RAPID DEVELOPMENT OF DIABATICALLY  
DRIVEN CONVECTION FROM EARLY THROUGH LATE AFTERNOON BEFORE LOSS OF  
DAYTIME HEATING AND A WELL MIXED ATMOSPHERE ENDS MOST PRECIPITATION.  
ONLY THREAT WILL BE FOR HEAVY RAIN AND GUSTY WINDS WITH SLOW MOVING  
PULSE CONVECTION.  
 
MONDAY, WE ARE UNDER THE INFLUENCE OF THE LEFT EXIT REGION OF A JET  
STREAK, WHILE THE CENTER OF THE 500MB LOW MOVES DIRECTLY OVERHEAD.  
THE SYSTEM RAPIDLY BECOMES STACKED LATE, WITH PROFILES STILL MOIST  
ADIABATIC AND WITH LITTLE SHEAR. LCLS REMAIN LOW - ABOUT 500FT,  
HOWEVER THERE IS LITTLE CAPE. THE FEATURE MAKES A SLOW DRIFT EAST  
AFTER THAT, WITH SOME FOLLOW ON SHOWERS GOING INTO TUESDAY.  
 
NOT CONFIDENT WITH THE BLENDED POP GUIDANCE THIS GO AROUND. SUNDAYS  
DIABATICALLY DRIVEN GENERIC "HEAT OF THE AFTERNOON" CONVECTION AND  
ABOUT 50% COVERAGE DURING THE AFTERNOON IS GOOD. AFTER THAT, TRENDED  
NUMBERS DOWN WITHOUT BROAD FORCING OVERHEAD AS THE CENTER OF THE  
UPPER LOW IS STILL WEST RIVER. AS THE UPPER LOW MOVES OVERHEAD  
MONDAY, GUIDANCE SUGGESTS A DECENT AREA OF HEAVIER QPF WITH A WELL  
DEVELOPED PV ANOMALY CROSSING EAST OF THE JAMES. TO THE WEST OF THIS  
FEATURE UNDER THE UPPER LOW, THERE WILL PROBABLY BE SOME SHOWER  
ACTIVITY, JUST NOT THRILLED WITH THE HIGH NUMBERS BLENDED GUIDANCE  
IS ADVERTISING, AND AS SUCH HAVE ADJUSTED DOWN FOR THE MISSOURI  
VALLEY AND WEST OF THE JAMES. PRECIPITATION WILL PROBABLY MIGRATE TO  
THE EAST AND OUT OF THE CWA QUICKER THAN ADVERTISED AS WELL WITH THE  
WEAKENING LOW.  
 
FLOW ALOFT IS MUCH MORE ZONAL FOR THE MIDDLE AND LATTER HALF OF THE  
WORK WEEK SO WE CAN ANTICIPATE A FEW WEAK/FAST MOVING WAVES, BEFORE  
FLOW BECOMES MORE OF A SOUTHWEST REGIME.  
 

 
   
AVIATION
 
(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)  
ISSUED AT 636 AM CDT SAT JUN 23 2018  
 
VFR CONDITIONS WILL PREVAIL EARLY ON IN THE TAF FORECAST PERIOD.  
AS THE DAY WEARS ON, -SHRA/SHRA AND -TSRA/TSRA WILL DEVELOP ACROSS  
THE REGION AND POSSIBLY AFFECT THE TAF SITES. LOWER END VFR CIGS,  
AND EVEN MVFR CIGS ARE POSSIBLE LATER TODAY AS THE PRECIPITATION  
DEVELOPS OVER THE AREA.  
 

 
   
ABR WATCHES/WARNINGS/ADVISORIES
 
 
SD...NONE.  
MN...NONE.  

 
 

 
 
UPDATE...MOHR  
SHORT TERM...TMT  
LONG TERM...CONNELLY  
AVIATION...TMT  
 
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