Area Forecast Discussion Issued by NWS Aberdeen, SD
000
FXUS63 KABR 140021 AAA
AFDABR
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ABERDEEN SD
721 PM CDT THU JUN 13 2013
.UPDATE...
00Z AVIATION DISCUSSION UPDATED BELOW.
&&
.SHORT TERM...TONIGHT THROUGH SATURDAY NIGHT
THE FORECAST CHALLENGE SURROUNDS CONVECTIVE POTENTIAL LATE TONIGHT
AND ON FRIDAY...AND WHETHER OR NOT ANY OF IT BECOMES STRONG TO
SEVERE.
CURRENTLY...HIGH PRESSURE IN PLACE AND A MOSTLY SUNNY SKY OVERHEAD
HAVE TEMPERATURES WARMING INTO THE 70S ACROSS THE CWA ON EAST TO
SOUTHEAST WINDS.
LATE TONIGHT THE RETURN FLOW/ELEVATED WAA PATTERN THAT SETS UP AS
HIGH PRESSURE SHIFTS EAST WILL SUPPORT ELEVATED SHOWER AND
THUNDERSTORM DEVELOPMENT MAINLY ACROSS THE WESTERN HALF OF THE
CWA. ANY EARLY MORNING CONVECTION WILL WORK NORTHEASTWARD ACROSS
THE REGION...LIKELY ENDING BY LATE MORNING. INCREASING EFFECTIVE
LAYER SHEAR AND EML INSTABILITY COULD BE ENOUGH TO GENERATE A
STRONG ELEVATED STORM OR TWO. BUT A GREATER THREAT FOR STRONG TO
SEVERE STORMS APPEARS TO RESIDE ACROSS THE EASTERN FORECAST AREA
/ALONG AND EAST OF THE JAMES RIVER VALLEY/ WHERE A SLIGHT RISK
AREA CONTINUES AT THIS TIME. AS A COLD FRONT SWEEPS ACROSS THE CWA
ON FRIDAY...A FEW STRONG TO SEVERE /SUPER CELLULAR/ THUNDERSTORMS
COULD DEVELOP...IF THE CAP CAN BE ERODED ENOUGH. A STRONG
MID-LEVEL WARM LAYER AT AND ABOVE 700HPA WILL BE IN PLACE WHICH
COULD END UP KEEPING THE LID ON AFTERNOON/EVENING CONVECTION.
THE MAJORITY OF FRIDAY NIGHT THROUGH SATURDAY NIGHT LOOKS TO BE
DRY WITH STABLE HIGH PRESSURE IN PLACE.
.LONG TERM...SUNDAY THROUGH THURSDAY
SHORTWAVE/OCCLUDED LOW WILL BE DRIFTING OVER THE NORTHER
PLAINS...FROM MANITOBA TO NORTHERN MINNESOTA SUNDAY NIGHT. TROF
PASSAGE WILL HAVE ALREADY OCCURRED...SO UNDER WEAK WESTERLY MID
LEVELS FLOW...AND A RELATIVELY DRY BOUNDARY LAYER...PROFILES
DURING PEAK HEATING WILL BE CONVECTIVELY UNSTABLE. COLD ADVECTION
TAKES OVER FOR THE START OF THE WORK WEEK...WITH H85 TEMPERATURES
DIPPING TO +10 TO +12C BY MONDAY PM.
THERE WILL BE A WEAK SHORTWAVE EMBEDDED WITHIN NORTHWEST FLOW
MONDAY PM AS WELL. SOUNDINGS AT THIS TIME ARE RELATIVELY
STABLE...SO EXPECTING DRY CONDITIONS WITH JUST A WIND SHIFT.
WARM ADVECTION KICKS IN LATE TUESDAY AS THE RIDGE AXIS STARTS TO
SHIFT EAST OF THE FORECAST AREA. WARMEST MID LEVEL AIR WILL
FOLLOW...DELAYED UNTIL THE END OF THE FORECAST PERIOD...LEAVING US
WITH SEVERAL DAYS IN WHICH WE COULD SEE MORE THUNDERSTORM
ACTIVITY.
&&
.AVIATION...
00Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
AN UPPER LOW PRESSURE TROUGH OVER THE WESTERN US THIS EVENING WILL
KICK NORTHEAST AND INTO SOUTHERN CANADA AND CLOSE OFF THROUGH
FRIDAY EVENING. AS A RESULT...A SURFACE COLD FRONT WILL SWEEP
ACROSS THE REGION THROUGH FRIDAY EVENING. SCATTERED SHOWERS AND
THUNDERSTORMS IN FAR EASTERN WYOMING WILL SWEEP EAST ACROSS THE
CWA TONIGHT AND EARLY FRIDAY AS THE UPPER LEVEL FORCING ALONG WITH
AN INCREASING LLJ MOVE EASTWARD. SOME OF THESE SHOWERS AND STORMS
MAY AFFECT THE TERMINALS. DUE TO THE UNCERTAINTY AND TIMING...LEFT
OUT THE MENTION OF SHOWERS AND THUNDER AT THE TERMINALS AT THIS
TIME. ALSO...THE MODELS INDICATE THE LOW LEVEL MOISTURE INCREASING
THROUGH THE NIGHT AND EARLY FRIDAY. THUS...EXPECT AN MVFR STRATUS
DECK TO DEVELOP NORTHWARD INTO THE CWA LATER TONIGHT AND EARLY
FRIDAY AND TRANSLATE EASTWARD THROUGH FRIDAY EVENING. THIS WILL
THEN MIX OUT/BECOME VFR AS SURFACE HEATING INCREASES AND DRIER AIR
BEHIND THE COLD FRONT MOVES IN. IT SHOULD BECOME BREEZY FROM THE
SOUTH SOUTHEAST TONIGHT AND FRIDAY AT THE TERMINALS. THE WINDS
WILL THEN TURN NORTHWEST AND BREEZY AT 15 TO 20 KNOTS WITH HIGHER
GUSTS AT PIR AND MBG IN THE LATE MORNING AND AFTERNOON AS HIGHER
MOMENTUM AIR MIXES DOWN BEHIND THE COLD FRONT.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...MOHR
SHORT TERM...DORN
LONG TERM...CONNELLY
AVIATION...MOHR
WEATHER.GOV/ABERDEEN