Area Forecast Discussion
Issued by NWS Aberdeen, SD

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS63 KABR 081526 AAA
AFDABR

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ABERDEEN SD
1026 AM CDT TUE JUL 8 2014

.UPDATE...
NO MAJOR CHANGES PLANNED TO THE CURRENT FORECAST. CLOUDS WILL
BEGIN TO INCREASE OVER THE NORTHEASTERN CWA OVER THE NEXT COUPLE
OF HOURS AND ISOLATED SHOWERS ARE STILL POSSIBLE THIS
AFTERNOON.


&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY THROUGH THURSDAY

NORTHWEST FLOW ALOFT WILL BRING BELOW NORMAL TEMPERATURES TO THE
REGION TODAY WITH HIGHS IN THE 70S TO THE LOWER 80S. SEVERAL
MODELS SUGGEST INSTABILITY SHOWERS WILL BE POSSIBLE IN NE SOUTH
DAKOTA AND WESTERN MINNESOTA THIS AFTERNOON. THERE WILL BE ENOUGH
UPPER LEVEL SUPPORT AND LOWER LEVEL MOISTURE TO RESULT IN AT LEAST
A SLIGHT CHANCE FOR SHOWERS AND THUNDERSTORMS. AN AREA OF HIGH
PRESSURE OVER THE REGION TONIGHT WILL BRING COOL AND DRY
CONDITIONS WITH TEMPERATURES IN THE 50S.

THE SURFACE HIGH PRESSURE WILL SHIFT SOUTHEAST OF THE REGION ON
WEDNESDAY ALLOWING FOR WEAK WAA TO SPREAD INTO THE DAKOTAS. WHILE
HIGHS WILL RANGE IN THE UPPER 70S TO THE MID 80S...THESE READINGS
ARE STILL A FEW DEGREES BELOW NORMAL. THE GFS IS SHOWING A RATHER
WEAK LLJ DEVELOPING WEDNESDAY NIGHT WITH PERHAPS AN ISOLATED
THUNDERSTORM ALONG I-90. THE NAM12 IS SHOWING A STRONGER LLJ AND A
BIT FATHER NORTH AS WELL. THIS LOOKS TOO AGGRESSIVE COMPARED TO ALL
OTHER MODELS.

AN AREA OF LOW PRESSURE OVER THE WESTERN DAKOTAS WILL BRING
SOUTHERLY WINDS AND INCREASING LLM TO THIS CWA ON THURSDAY. A
SHORT WAVE MOVING ACROSS THE REGION WILL INTERACT WITH THE LLM TO
RESULT IN A CHANCE FOR SHOWERS AND THUNDERSTORMS.

.LONG TERM...THURSDAY NIGHT THROUGH MONDAY

FORECAST FOCUS IS ON PRECIPITATION CHANCES THROUGH THE
WEEKEND...THEN A POSSIBLE SIGNIFICANT PATTERN CHANGE EARLY NEXT
WEEK.

THURSDAY NIGHT THROUGH SUNDAY...FORECAST CONFIDENCE: MODERATE

EXTENDED PERIOD WILL START OFF WITH A QUASI-ZONAL FLOW PATTERN OVER
THE NORTHERN PLAINS MIDWEEK. A COUPLE OF WEAK...LOW AMPLITUDE
SHORTWAVES ARE EXPECTED TO TRAVERSE THE AREA FROM WEST TO
EAST...THE FIRST ON THURSDAY NIGHT WITH A SECOND OVER THE WEEKEND.
THE DETERMINISTIC MEDIUM RANGE MODELS CONTINUE TO SUGGEST THE
HIGHEST POTENTIAL FOR PRECIPITATION WILL OCCUR THURSDAY
NIGHT...ALTHOUGH IT SHOULD BE NOTED THAT THE LLJ NOW APPEARS TO BE
A BIT FURTHER SOUTH AND EAST OF THE AREA. COULD SEE SOME LINGERING
PRECIPITATION EARLY FRIDAY...WITH THE POSSIBILITY FOR THUNDERSTORMS
TO RE-DEVELOP ON FRIDAY AFTERNOON/EVENING ALONG A WEAK FRONTAL
BOUNDARY. AT THIS POINT...OVERALL SYNOPTIC SCALE FORCING ON FRIDAY
APPEARS RATHER WEAK SO COVERAGE OF STORMS WILL LIKELY BE LOW. A
SLIGHTLY STRONGER PERTURBATION MAY EMANATE OUT OF THE DESERT
SOUTHWEST THIS WEEKEND...SO CONTINUED CHANCE OR SLIGHT CHANCE
PROBABILITIES RIGHT INTO SUNDAY. THERE WILL LIKELY PLENTY OF DRY
PERIODS IN THIS TIMEFRAME...SO NO ALL DAY RAINS EXPECTED. AS FOR
TEMPERATURES...READINGS THROUGH THE WEEKEND ARE EXPECTED TO VERY
CLOSE TO MID-JULY AVERAGES...HIGHS IN THE 80S TO AROUND 90 AND
LOWS IN THE 60S.

SUNDAY NIGHT INTO EARLY NEXT WEEK...FORECAST CONFIDENCE: LOW

BY EARLY NEXT WEEK...A FAIRLY SIGNIFICANT PATTERN CHANGE IS POSSIBLE
AS THE UPPER LEVEL PATTERN BECOMES MUCH MORE AMPLIFIED. A LARGE
UPPER RIDGE IS EXPECTED OVER THE INTERMOUNTAIN WEST...WITH A
STRONG UPPER LOW EXPECTED TO DROP SWD OUT OF THE HUDSON BAY
REGION OF CANADA INTO THE GREAT LAKES REGION. THIS WOULD PLACE THE
DAKOTAS IN A PERSISTENT NORTHERLY FLOW PATTERN...WITH 850MB TEMPS
TRENDING AS COOL AS THE SINGLE DIGITS ABOVE ZERO...OR ABOUT -2.0 STD
DEVIATIONS BELOW NORMAL. THERE ARE STILL TIMING/AMPLITUDE
DIFFERENCES BETWEEN THE GFS/ECMWF/GEM MODELS...RESULTING IN A
LOW CONFIDENCE TEMPERATURE FORECAST. CURRENT CONSENSUS/ALLBLEND
FORECAST IS INDICATING HIGHS ON MONDAY IN THE MID/UPPER 70S.
HOWEVER...IF THE 08.00Z ECMWF IS CORRECT...READINGS MAY STRUGGLE
TO REACH THE UPPER 60S! WITH A COOL CANADIAN AIRMASS IN
PLACE...CONDITIONS SHOULD REMAIN DRY.


&&

.AVIATION...
12Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS

VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH THIS TAF PERIOD.
ALTHOUGH A SCT/BKN DECK OF CLOUDS IS EXPECTED TO DEVELOP...CIGS
SHOULD REMAIN AOA 3K FEET AGL.  A WEAK DISTURBANCE DROPPING IN
FROM THE NORTH COMBINED WITH RESIDUAL MOISTURE MAY TRIGGER
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS DURING THE LATE
AFTERNOON PEAK HEATING HOURS. ALTHOUGH KABR/KATY COULD BE
IMPACTED...THE LIMITED AREAL COVERAGE OF PCPN WILL PRECLUDE
MENTION IN THIS TAF CYCLE. A RELATIVELY TIGHT PRESSURE GRADIENT
REMAINS OVER THE DAKOTAS...AND NORTHWEST WINDS WILL BECOME BREEZY
FROM MID-MORNING THROUGH THE AFTERNOON HOURS. GUSTS TO 20 OR 25
KTS ARE EXPECTED.


&&

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

$$
UPDATE...WISE
SHORT TERM...SD
LONG TERM...FOWLE
AVIATION...FOWLE

WEATHER.GOV/ABERDEEN






USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.