000
FXUS63 KABR 200856
AFDABR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ABERDEEN SD
356 AM CDT THU JUN 20 2013
.SHORT TERM...TODAY THROUGH SATURDAY
CURRENTLY...THERE IS ONGOING CONVECTION ACROSS THE NORTHEAST
CWA...WITH ADDITIONAL DEVELOPMENT BEGINNING FURTHER WEST AS THE
NOSE OF THE LLJ MOVES EASTWARD THIS MORNING. KEPT SHOWER AND
THUNDERSTORMS MENTIONED IN THE FORECAST THOUGH THE MORNING HOURS.
UNSURE OF THE AMOUNT OF CLOUD COVER THAT WILL BE LEFT OVER ACROSS
THE REGION FROM THIS EARLY MORNING CONVECTION...BUT IT MAY
INHIBIT DAYTIME HEATING THIS AFTERNOON...SO SOME UNCERTAINTY
STILL REMAINS IN THE AFTERNOON FORECAST. OTHERWISE...THE SURFACE
LOW TRACKS EAST INTO THE CENTRAL PLAINS STATES WITH AN INVERTED
TROUGH/COLD FRONT MOVING ACROSS THE NORTHERN PLAINS. THIS
FEATURE...ALONG WITH WEAK SHORTWAVE ENERGY MOVING THROUGH
SOUTHWEST FLOW ALOFT...SHOULD RESULT IN ENOUGH LIFT TO SPARK
AFTERNOON THUNDERSTORMS. MODELS HAVE BEEN SLIGHTLY OVERDOING
DEWPOINTS OVER THE LAST COUPLE OF DAYS...HOWEVER...WITH THE
STRONG SOUTHERLY FETCH AND GULF MOISTURE STREAMING NORTHWARD...MID
TO UPPER 60S ARE LIKELY. MODEL ML CAPE VALUES ARE EXCEEDING 2000
J/KG AND 0-6 KM SHEAR AROUND 30-40 KTS...AND ALONG WITH STEEP MID
LEVEL LAPSE RATES...THE ATMOSPHERE WILL BE SUPPORTIVE OF SEVERE
STORMS THIS AFTERNOON...ESPECIALLY ACROSS THE EASTERN HALF OF THE
CWA. IT APPEARS AS THOUGH WIND AND HAIL WILL BE THE MAIN
THREATS...BUT CANNOT COMPLETELY RULE OUT THE TORNADO POTENTIAL
EITHER.
THE LLJ LOOKS LIKE IT WILL SET UP EAST OF THIS CWA THURSDAY
NIGHT/FRIDAY MORNING...SO THERE MAY BE A BRIEF BREAK IN THE
ACTION OVERNIGHT. THE SURFACE LOW WILL INTENSIFY OVER THE CENTRAL
PLAINS AND MOVE NORTH THROUGH THE AFTERNOON. THIS WILL RESULT IN A
NORTHWARD MOVING WARM FRONT...SITUATING ITSELF OVER OUR CWA DURING
PEAK HEATING ON FRIDAY AFTERNOON. MODELS HAVE CONSISTENTLY TRENDED
700 MB TEMPERATURES DOWNWARD /NOW ONLY RANGING FROM ABOUT 9 TO 12
C ACROSS THE CWA/...SO WHILE IT PREVIOUSLY APPEARED THAT THE
REGION WOULD BE CAPPED OF...IT SEEMS AS THOUGH THIS WILL NOW BE
LESS OF A FACTOR. IT WILL BE A VERY UNSTABLE ENVIRONMENT
SUPPORTIVE OF RAPID GROWTH AND SEVERE CONVECTION. ML CAPE VALUES
WILL EXCEED 3000 J/KG...ALONG WITH NICELY CURVED HODOGRAPHS AND
RESULTANT 0-6 KM SHEAR VALUES IN THE 40 TO 50 KT RANGE. CONFIDENCE
IN SEVERE STORMS FRIDAY AFTERNOON AND NIGHT INCREASES WITH EVERY
MODEL RUN.
THE SEVERE THREAT CONTINUES THROUGH SATURDAY AS WELL. THE SURFACE
LOW WILL MOVE NORTHEAST...PUSHING THE WARM FRONT NORTH OF THE
REGION AND SWEEPING A COLD FRONT ACROSS OUR CWA. THE VERY UNSTABLE
AIR MASS REMAINS IN PLACE. MOST MODELS AGREE ON 700 MB
TEMPERATURES FROM 12 TO 14 C ACROSS MOST OF THE CWA HOWEVER...SO
AFTERNOON CONVECTION MAY INITIALLY BE CAPPED OFF. WILL CONTINUE TO
MONITOR THE SEVERE POTENTIAL OVER THE WEEKEND.
.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY
THE REGION WILL BE UNDER SOUTHWESTERLY UPPER LEVEL FLOW WHEN THE
PERIOD BEGINS AS A COUPLE OF SHORTWAVE TROUGHS TRACK NORTHWEST OF
THE AREA BETWEEN SATURDAY NIGHT AND TUESDAY. THE FLOW BECOMES MORE
NORTHWESTERLY ON WEDNESDAY AS RIDGING BUILDS OVER THE ROCKIES.
SURFACE LOW PRESSURE WILL BE OVER THE NORTHERN AND CENTRAL PLAINS
SATURDAY NIGHT...WITH A BOUNDARY IN PLACE OVER THE CWA. WILL
LIKELY SEE ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS AS FAIRLY
STRONG INSTABILITY WILL BE IN PLACE DURING THE EVENING...WITH CAPE
VALUES IN EXCESS OF 5000 J/KG AND LIS BETWEEN -10 AND -12. 0-6 KM
BULK SHEAR VALUES ARE NOT REAL STRONG TO START THE EVENING...BUT
INCREASE TO 50 TO 60 KTS ACROSS THE WEST DURING THE OVERNIGHT
HOURS...ALONG WITH AN INCREASING LLJ. THE ONE POSSIBLE HINDERING
FACTOR WILL BE A MID LEVEL CAP...WITH H7 TEMPS IN THE +12 TO +14
DEGREE RANGE DURING THE EVENING. HOWEVER...THIS CAP DOES WEAKEN
QUITE A BIT AS THE OVERNIGHT PERIOD GOES ON. THE SYSTEM PUSHES OFF
TO THE NORTHEAST ON SUNDAY...WITH MOST OF THE REGION REMAINING DRY
SUNDAY AND SUNDAY NIGHT. MAY SEE A FEW SHOWERS AND STORMS MONDAY
AND MONDAY NIGHT AS ANOTHER SYSTEM PUSHES THROUGH...THEN THE
REGION LOOKS TO BE DRY TUESDAY AND WEDNESDAY AS HIGH PRESSURE
BUILDS IN.
ABOVE NORMAL TEMPERATURES WILL BE COMMON THROUGHOUT THE
PERIOD...WITH DAYTIME HIGHS IN THE 80S TO LOWER 90S...AND
OVERNIGHT LOWS IN THE 60S.
&&
.AVIATION...
06Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
SCATTERED THUNDERSTORMS WILL TRACK ACROSS PORTIONS OF THE
NORTHEASTERN CWA DURING THE OVERNIGHT HOURS...BUT WILL NOT AFFECT
KABR OR KATY. A FEW MORE MAY REACH THE FAR SOUTHWESTERN CWA
TOWARD SUNRISE...POSSIBLY AFFECTING KPIR. ANOTHER ROUND OF SHOWERS
AND THUNDERSTORMS IS EXPECTED TO DEVELOP DURING THE AFTERNOON AND
EVENING HOURS...AFFECTING MAINLY THE CENTRAL AND EASTERN CWA. MVFR
CIGS AND MVFR/IFR VSBYS ARE POSSIBLE WITH THE STRONGER STORMS.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
SHORT TERM...SERR
LONG TERM...PARKIN
AVIATION...PARKIN
WEATHER.GOV/ABERDEEN
