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000
FXUS63 KABR 240912
AFDABR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ABERDEEN SD
412 AM CDT FRI MAY 24 2013

.SHORT TERM...TODAY THROUGH SUNDAY
CURRENT SURFACE ANALYSIS SHOWS A DEEPENING LOW WORKING ITS WAY
INTO EASTERN WYOMING THIS MORNING AND A VERY STRONG PRESSURE
GRADIENT HAS SET UP ACROSS WESTERN SOUTH DAKOTA. ALREADY SEEING
SEVERAL SITES ACROSS WESTERN SOUTH DAKOTA REPORTING GUSTS IN
EXCESS OF 30 MPH THIS MORNING. ALSO WATCHING WARM MOIST AIR SURGE
INTO THE CENTRAL PLAINS...ALONG WITH AN ASSOCIATED STRATUS LAYER
NOSING INTO FAR SOUTHWEST SOUTH DAKOTA. THE WARM AIR ADVECTION AND
RETURN OF MOISTURE WILL INHIBIT MIXING POTENTIAL THIS
AFTERNOON...BUT BASED OFF THE STRENGTH OF THE SURFACE PRESSURE
GRADIENT AND THE BUFKIT MOMENTUM TRANSFER TOOL CONSISTENTLY
SHOWING 35 TO 40 KTS AVAILABLE TO BE MIXED TO THE
SURFACE...BELIEVE THAT THE WESTERN HALF OF THE CWA WILL REACH WIND
ADVISORY CRITERIA THIS MORNING AND AFTERNOON. ALSO...THERE MAY BE
SOME SHOWERS THAT DEVELOP DUE TO ISENTROPIC LIFT ACROSS THE
EASTERN CWA THIS AFTERNOON /NO OTHER UPPER LIFT TO SPEAK OF WITH
THE UPPER RIDGE OVERHEAD/. VERY LITTLE IF ANY INSTABILITY ACROSS
THIS REGION...SO MAINLY EXPECTING VERY LIGHT RAIN SHOWERS...WITH
PERHAPS AN ISOLATED THUNDERSTORM IN THE AFTERNOON.

BY SATURDAY...THE UPPER RIDGE SLOWLY BEGINS TO SHIFT EASTWARD AS
THE UPPER CLOSED LOW SPINS AROUND THE PACIFIC NORTHWEST/NORTHERN
ROCKIES/SOUTHWEST CANADA. EVEN THOUGH THE UPPER FLOW TRANSITIONS
TO A MORE SOUTHWESTERLY DIRECTION...STILL NOT SEEING ANY
SIGNIFICANT 500 MB HEIGHT FALLS...AND IT IS HARD TO PICK OUT ANY
DISTINCT SHORTWAVES MOVING ACROSS THE REGION. HOWEVER...GULF
MOISTURE WILL CONTINUE TO SURGE NORTHWARD AND ML CAPE VALUES WILL
RISE TO 2000 J/KG ACROSS SOUTH CENTRAL SOUTH DAKOTA. ALONG WITH
0-6 KM SHEAR VALUES IN THE 30 TO 40 KT RANGE...THE ENVIRONMENT
WILL CERTAINLY BE CONDUCIVE FOR STRONG THUNDERSTORM DEVELOPMENT.
AT THIS POINT IT LOOKS LIKE IT MAY BE A SITUATION WHERE
THUNDERSTORMS WILL BEGIN ACROSS THE WESTERN PART OF THE STATE AND
TRACK EASTWARD.

NOT SEEING A REAL STRONG OR WELL DEFINED LLJ JET SET UP SATURDAY
NIGHT/SUNDAY MORNING...HOWEVER SUNDAY AFTERNOON WILL BE VERY
SIMILAR TO SATURDAY...WITH PLENTY OF MOISTURE...INSTABILITY AND
SHEAR ACROSS THE CWA. MODELS ARE ALSO SUGGESTING SEVERAL WAVES OF
ENERGY MOVING THROUGH SOUTHWEST FLOW ALOFT ON SUNDAY. WILL HAVE TO
MONITOR TIMING AND WHERE/WHEN STORMS MAY INITIATE.

.LONG TERM...SUNDAY NIGHT THROUGH THURSDAY
STILL LOOKING AT A PROLONGED PERIOD OF SWRLY FLOW ALOFT UNTIL
THURSDAY /AT THE EARLIEST/...WITH SHORT-WAVES ABOUNDING IN SAID
UPPER FLOW. AT SOME POINT LATE IN THE WEEK...THE MAJORITY OF
EMBEDDED SHORTWAVE ENERGY WITHIN THE WESTERN CONUS LONGWAVE TROF
INFLUENCES THE PAC NW UPPER TROF TO EMERGE OUT ONTO THE NORTHERN
PLAINS...TRANSITIONING PRECIPITATION THREAT FROM TRANSIENT ROUNDS
OF CONVECTION TO MORE OF A SYNOPTIC SCALE LOW PRESSURE DRIVEN
WAA-FORCED BROADER AND SLOWER MOVING PRECIPITATION SHIELD. NO
PLANS TO STRAY FROM SUPER WET ALLBLEND POPS IN THE EXTENDED. AS
FOR TEMPERATURES...925HPA AND 850HPA THERMAL PROGS DO SHOW A
WARMING TREND THROUGH THE WEEK FROM HIGHS CLOSER TO 70 ON MONDAY
TO HIGHS CLOSER TO 80 ON THURSDAY.

&&

.AVIATION...
06Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS

VFR CONDITIONS WILL PREVAIL OVERNIGHT AND THROUGH THE DAY FRIDAY.
SOUTH TO SOUTHEASTERLY WINDS WILL INCREASE INTO THE 20 TO 35 MPH
RANGE BY LATE MORNING. SCATTERED SHOWERS...AND A THUNDERSTORM OR
TWO...ARE POSSIBLE DURING THE AFTERNOON HOURS AS WELL. FOR
NOW...HAVE JUST MENTIONED VCSH AT ALL TAF SITES DUE TO UNCERTAINTY
OF TIMING AND EXACT LOCATION OF DEVELOPMENT.

&&

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

$$
SHORT TERM...SERR
LONG TERM...DORN
AVIATION...DORN

WEATHER.GOV/ABERDEEN