Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 251447
AFDBIS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
947 AM CDT SAT JUL 25 2015

.UPDATE...
ISSUED AT 941 AM CDT SAT JUL 25 2015

MCS ACROSS THE ND/SD BORDER DIURNALLY TRENDING DOWN THIS MORNING
WITH THE CLOUD SHIELD DIMINISHING. SO DID SOME CLOUD AND POP
UPDATES THIS MORNING. TRIMMED POPS BACK JAMES RIVER VALLEY WEST
TO THE MISSOURI RIVER THROUGH EARLY AFTERNOON.

UPDATE ISSUED AT 559 AM CDT SAT JUL 25 2015

QUICK UPDATE TO LOWER POPS AND CONFINE ISOLATED SHOWERS AND
THUNDERSTORMS TO THE FAR SOUTH THROUGH THE MORNING HOURS. THE
RAP13 APPEARS TO HAVE A MUCH BETTER HANDLE THAN THE HRRR IN TERMS
OF MOVING/DEVELOPING AN AREA OF THUNDERSTORMS IN NORTHWESTERN
SOUTH DAKOTA. EARLIER IT APPEARED THAT THIS WOULD MOVE STEADILY
NORTHEAST BUT LATEST TRENDS SUGGEST A MORE EASTWARD MOVEMENT. THIS
WILL LIMIT POPS ACROSS SOUTHWEST AND SOUTH CENTRAL NORTH DAKOTA.
IR CLOUDS TOP TEMPS OF -54C REPRESENTS A CIRRUS SHIELD WITH HEIGHTS
BETWEEN 30KFT AND 35KFT. UPDATES FORTHCOMING.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 415 AM CDT SAT JUL 25 2015

THE LATEST WATER VAPOR IMAGERY SHOWS A SOUTHWEST FLOW INTO
WESTERN AND CENTRAL NORTH DAKOTA WITH A FEW EMBEDDED MID LEVEL
SHORTWAVE TROUGHS. THESE SHORTWAVE TROUGHS WERE LOCATED IN
SOUTHEAST MONTANA...NORTHERN WYOMING...AND WESTERN SOUTH DAKOTA.
REGIONAL RADAR SHOWING A GROWING AREA OF SHOWERS AND THUNDERSTORMS
OVER SOUTHEAST MONTANA INTO CENTRAL AND NORTHERN SOUTH DAKOTA.
BOWMAN RADAR ALSO DEPICTS THE LEADING EDGE OF LIGHT SHOWERS
SCOOTING OVER THE FAR SOUTHWEST. MAIN THEME TODAY WILL BE ISOLATED
TO SCATTERED SHOWERS AND THUNDERSTORMS OVER SOUTHWEST NORTH DAKOTA
EARLY THIS MORNING...CONTINUING DURING THE DAY...AND GRADUALLY
EXPANDING INTO CENTRAL NORTH DAKOTA THROUGH THE AFTERNOON AND
EARLY EVENING. ALTHOUGH THE GFS/ECMWF KEEP THE MAXIMUM CAPE AND
0-6KM SHEAR DISPLACED FROM EACH OTHER...VALUES ARE STILL HIGH
ENOUGH FOR THE AFOREMENTIONED SHORTWAVES TO WORK WITH RESULTING IN
STRONG TO ISOLATED SEVERE THUNDERSTORMS TODAY...ESPECIALLY ACROSS
THE SOUTH. SPC HAS THE SLIGHT RISK AREA APPROACHING OUR SOUTHERN
BORDER TODAY WITH MARGINAL CRITERIA COVERING ALL EXCEPT THE FAR
NORTHWEST. THE SHOWERS/THUNDERSTORMS WILL MAINLY RESIDE ACROSS THE
JAMES RIVER VALLEY SATURDAY EVENING/NIGHT AS THE SHORTWAVES
MIGRATE EAST. AFTERNOON HIGHS TODAY WILL REACH WELL INTO THE
80S...WITH LOWER 90S IN THE NORTHWEST.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 415 AM CDT SAT JUL 25 2015

ZONAL MID LEVEL FLOW IN THE SHORT TERM TRANSITIONS TO SOUTHWEST
FLOW AS THE WEST COAST TROUGH DEEPENS...AND THEN BEGINS TO PUSH
OVER THE ROCKIES MONDAY. WEAK WAVES IN THE FLOW INTO MONDAY KEEP
LOWER POPS IN THE FORECAST FOR EACH DAY. BY MONDAY...AS THE LONG
WAVE TROUGH APPROACHES...SURFACE LOW PRESSURE OVER EASTERN MONTANA
INTENSIFY WITH STRONG WARM AIR AND MOISTURE ADVECTION INTO
WESTERN NORTH DAKOTA...TEMPERATURES SOLIDLY INTO THE MID 90S...AND
WIND SPEEDS APPROACHING ADVISORY THRESHOLDS.

SEVERE WEATHER PARAMETERS BECOME MORE FAVORABLE LATER MONDAY DUE
IN PART TO THE INCREASING MOISTURE...BUT ALSO IN THE BREAK OUT OF
SUNSHINE IN A CLEAR SLOT...AND NEAR THE FRONTAL TRIPLE POINT.
VERY STRONG THERMODYNAMICS SHOULD ALSO BE PRESENT ACROSS THE
POWERFUL COLD FRONT...FURTHER ENHANCING STORMS. SEVERE STORMS
WILL BE POSSIBLE MONDAY AND MONDAY NIGHT.

FOR TUESDAY A SIGNIFICANT COOL DOWN IS PREDICTED WITH HIGHS IN THE
NORTHWEST PART OF NORTH DAKOTA ONLY REACHING AROUND 70 BEHIND THE
ANOMALOUSLY DEEP SYSTEM...FOR THE END OF JULY...MOVING THROUGH
SOUTHERN SASKATCHEWAN. EXPECT GUSTY WINDS.

DRY FOR THE MIDDLE TO LATTER PARTS OF NEXT WEEK WITH HIGHS MAINLY
IN THE 80S.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 941 AM CDT SAT JUL 25 2015

SURFACE TROUGH ACROSS EASTERN MONTANA WILL BE THE FOCUS FOR
SCATTERED THUNDERSTORMS ACROSS WESTERN AND CENTRAL NORTH DAKOTA
THIS AFTERNOON AND EVENING. VFR CIGS/VSBYS NEXT 24HR. VCTS WILL
BE MAINTAINED FROM EARLY AFTERNOON INTO THE EARLY EVENING TIME
PERIOD AT ALL TERMINALS EXCEPT KISN.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...WAA
SHORT TERM...KS
LONG TERM...JPM
AVIATION...WAA



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