000
FXUS63 KABR 161801 AAA
AFDABR

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ABERDEEN SD
101 PM CDT THU MAY 16 2013

.UPDATE...
18Z AVIATION DISCUSSION UPDATED BELOW.

A COUPLE OF QUICK ADJUSTMENTS. FOR POPS...GETTING A LITTLE MORE
PROGRESSIVE MOVEMENT WITH LIGHT PRECIPITATION NORTH OF PIERRE TO
MOBRIDGE AND NORTHWEST OF ABERDEEN...AS WELL AS THE CONVECTIVE
CLUSTER IN NEBRASKA THAT WILL SKIRT SOUTH OF I90 FORECAST AREA.
AHEAD OF THIS...WINDS/DEWPOINTS HAVE NOT RESPONDED FAVORABLY...WITH
BETTER MIXING AND WARMER TEMPERATURES...SO HAVE ADJUSTED A FEW
SPOTS AND FIRE WEATHER FORECAST.


&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY THROUGH SATURDAY
PRECIPITATION/SEVERE CHANCES OVER THE NEXT COUPLE OF DAYS WILL BE
THE MAIN FORECAST CHALLENGE.

A VIGOROUS SHORT WAVE WILL TRACK ACROSS THE REGION OVER THE NEXT
24 HOURS. WHILE CAPE VALUES ARE RATHER UNIMPRESSIVE FOR MUCH OF
THIS CWA...THERE ARE DECENT ML-CAPE VALUES AND 0-6KM BULK SHEAR
VALUES ALONG AND SOUTH OF I-90 AFTER 18Z. WOULD NOT BE TOO
SURPRISED IF SOME THUNDERSTORMS SOUTH OF THIS CWA BECOME STRONG
AND PRODUCE SMALL HAIL. THIS SHORT WAVE WILL INTERACT WITH AN
INCREASING LLJ TONIGHT TO PRODUCE SHOWERS AND THUNDERSTORMS FOR
THE I-29 CORRIDOR. PCPN SHOULD EXIT THE REGION BETWEEN 15-18Z
FRIDAY WITH THE REST OF THE DAY BEING MOSTLY DRY AND WARM. HIGH
TEMPERATURES WILL WARM INTO THE 80S TO AROUND 90 DEGREES FOR
SOUTH CENTRAL SOUTH DAKOTA. WARM TEMPERATURES AT H7 OF 9C WILL
CAP OFF CONVECTION UNTIL THE LATE AFTERNOON ON FRIDAY. BASED ON
THE NAM12...STRONG TO PERHAPS SEVERE STORMS WILL DEVELOP ALONG A
DRY LINE OVER THE BLACK HILLS. THESE STORMS WILL MOVE DUE EAST
ALONG AN INSTABILITY AXIS WHICH WOULD CLIP THE SOUTHWEST CWA.

ADDITIONAL THUNDERSTORM ACTIVITY IS EXPECTED DURING THE AFTERNOON
HOURS ON SATURDAY AS A LOW PRESSURE SYSTEM MOVES ACROSS THE AREA.
WAA ALONG WITH MOISTURE ADVECTION WILL SPREAD INTO EASTERN SOUTH
DAKOTA WITH HIGHS LIKELY REACHING THE MID 80S. THIS WARM AIR ALONG
WITH DEW POINTS IN THE MID 60S WILL PRODUCE ML-CAPE VALUES OVER
4000 J/KG. WITH 0-6KM BULK SHEAR VALUES AROUND 30 KNOTS PLUS OVER
1000 J/KG OF CAPE IN THE HAIL GROWTH ZONE...LARGE HAIL SEEMS
HIGHLY POSSIBLE. BASED ON THE VGP AND 0-3KM HELICITY...TORNADOES
COULD BE POSSIBLE AS WELL. MAY NEED TO ADD SEVERE MENTION INTO THE
FORECAST IN THE NEAR FUTURE.



.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY
AN UPPER LEVEL TROUGH WILL BE OVER THE ROCKIES WHEN THE PERIOD
STARTS...WITH SHORTWAVE ENERGY RIDING UP THE EAST SIDE OF IT AND
OVER THE NORTHERN PLAINS. THE TROUGH BECOMES A CLOSED LOW THAT
WILL SPIN OVER THE NORTHERN PLAINS SUNDAY NIGHT THROUGH THE DAY
TUESDAY BEFORE GETTING PUSHED EAST AHEAD OF A BUILDING RIDGE.

AN ELONGATED SURFACE LOW WILL BE OVER THE WESTERN PLAINS SATURDAY
EVENING...THEN PUSHES EASTWARD AND SPINS UP OVER THE NORTHERN
PLAINS SUNDAY NIGHT THROUGH EARLY WEDNESDAY. A WIDE OPEN GULF WILL
ALLOW FOR AMPLE MOISTURE WITH THIS SYSTEM. THE MODELS ARE IN GOOD
AGREEMENT WITH FAIRLY POTENT INSTABILITY DEVELOPING ACROSS THE
ENTIRE AREA SATURDAY NIGHT...WITH SOMEWHAT WEAKER INSTABILITY
ACROSS THE EASTERN CWA SUNDAY NIGHT. THE ENTIRE CWA IS CURRENTLY
IN THE DAY 3 SLIGHT RISK OUTLOOK. WITH THE ABUNDANT MOISTURE AND
INSTABILITY AROUND...A 40-45 KT LLJ NOSING ITS WAY OVER THE
EASTERN PART OF THE CWA...AND H7 TEMPERATURES ONLY AROUND
+8...EXPECT THERE WILL BE SOME SEVERE STORMS AROUND SATURDAY
EVENING. GENERALLY LOOKING AT PRECIPITATION CHANCES SATURDAY NIGHT
THROUGH THE DAY TUESDAY. THE MODEL SOLUTIONS BEGIN TO DIVERGE
AFTER THAT WITH THE GFS KEEPING SCATTERED SHOWERS OVER THE AREA
TUESDAY NIGHT AND WEDNESDAY...WHILE THE ECMWF DROPS HIGH PRESSURE
AND DRY CONDITION OVER THE REGION. WILL STICK FAIRLY CLOSE TO THE
ALLBLEND TEMPERATURES...WHICH BEGIN TO TAPER OFF DRASTICALLY BY
TUESDAY NIGHT.

NEAR TO SLIGHTLY BELOW NORMAL TEMPERATURES ARE EXPECTED THROUGH
THE PERIOD...WITH THE COOLER TEMPERATURES OCCURRING ON SUNDAY AND
MONDAY WHEN ABUNDANT CLOUD COVER AND PRECIPITATION LOOK TO HINDER
WARMING.




&&

.AVIATION...
18Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS

A SHORT WAVE LOW PRESSURE TROUGH AND WAA WERE BRINGING MID LEVEL
CLOUDS ALONG WITH SOME MAINLY LIGHT SHOWERS TO CENTRAL AND NORTH
CENTRAL SOUTH DAKOTA EARLY THIS AFTERNOON. WITH NOT MUCH FOR
INSTABILITY ALONG WITH HIGH CLOUD BASES AND BIG DEW POINT
SPREADS/LOW LEVEL DRY AIR ACROSS THE REGION...DONT EXPECT MUCH
FOR ANY THUNDER WITH THIS AREA AS IT MOVES EAST INTO THE EVENING
ALONG WITH RAINFALL AT THE SURFACE. THUS...HAVE VFR MID LEVEL
CLOUDS IN THE TERMINALS ALONG WITH SHOWERS AT OR IN THE VICINITY
OF THE TERMINALS INTO THE AFTERNOON AND EVENING HOURS.



&&

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

$$
UPDATE...CONNELLY/MOHR
SHORT TERM...SD
LONG TERM...PARKIN
AVIATION...MOHR

WEATHER.GOV/ABERDEEN