000
FXUS63 KBIS 191515
AFDBIS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
1015 AM CDT WED JUN 19 2013

.UPDATE...
ISSUED AT 954 AM CDT WED JUN 19 2013

THIS UPDATE WILL BE FOCUSED ON THE THUNDERSTORM POTENTIAL AND
INITIATION. CURRENT TRENDS SHOW THUNDERSTORMS IN CENTRAL SOUTH
DAKOTA. CURRENT INDICATIONS ARE THIS AREA WILL MOVE NORTH INTO
SOUTH CENTRAL NORTH DAKOTA LATER THIS AFTERNOON. ELEVATED MIXED
LAYER ACROSS SOUTHWEST NORTH DAKOTA SHOULD LIMIT DEVELOPMENT
THERE. AN ISOLATED SHOWER MOVING ALONG NORTHWEST ND BORDER SHOULD
DIMINISH WITH TIME. WAITING FOR WINDS TO PICK UP SOUTHWEST.
WINDS WILL STEADILY PICK UP BY NOON A LITTLE SLOWER THAN EARLIER
FORECAST.


UPDATE ISSUED AT 647 AM CDT WED JUN 19 2013

NO SIGNIFICANT CHANGES TO PREVIOUS FORECAST. STILL UNCERTAINTY AS
TO POTENTIAL FOR CONVECTION TO DEVELOPMENT THIS AFTERNOON WITHIN
INITIAL WARM AIR ADVECTION. CONVECTION SPREADING INTO THE
WEST/NORTH IS A BETTER BET FOR LATE TONIGHT.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 351 AM CDT WED JUN 19 2013

THERE ARE MULTIPLE CONCERNS FOR THE SHORT TERM PERIOD INCLUDING
THUNDERSTORMS / SEVERE WEATHER POSSIBILITIES...AND THE POTENTIAL
FOR A WIND ADVISORY IN THE SOUTHWEST.

A WARM FRONT LOCATED FROM CENTRAL MONTANA INTO EASTERN WYOMING IS
EXPECTED TO LIFT NORTH TODAY INTO TONIGHT. THE BOUNDARY IS
EXPECTED TO BE LOCATED FROM NORTHEAST MONTANA INTO SOUTH CENTRAL
NORTH DAKOTA BY EARLY THURSDAY MORNING. INCREASING H85 WARM AIR
ADVECTION ASSOCIATED WITH THE WARM FRONT AND AN INCREASING LOW
LEVEL JET SHOULD PROVIDE SUPPORT FOR A FEW THUNDERSTORMS LATER
THIS AFTERNOON INTO TONIGHT. THE LATEST 4KM WRF-NMM SUGGESTS
THUNDERSTORMS COULD BEGIN IN PARTS OF CENTRAL NORTH DAKOTA THIS
AFTERNOON BEFORE INCREASING IN COVERAGE LATER THIS EVENING.

ANOTHER CONCERN IS THAT THUNDERSTORMS WHICH DEVELOP LATER TODAY
ACROSS ACROSS PARTS OF CENTRAL AND EASTERN MONTANA WILL MOVE INTO
WESTERN NORTH DAKOTA TONIGHT IN THE FORM OF AN MCS. MLCAPE VALUES
OF 1500-2500 J/KG ARE SHOWN BY THE 19.00Z NAM THIS AFTERNOON INTO
TONIGHT ACROSS MUCH OF CENTRAL AND WESTERN NORTH DAKOTA. DEEP
LAYER SHEAR WILL INCREASE TONIGHT IN CONCERT WITH THE LOW LEVEL
JET...WHICH SHOULD HELP ENHANCE THE SEVERE WEATHER THREAT.

WILL FOCUS THE MAIN SEVERE WEATHER POTENTIAL IN THE GRIDS ACROSS
WESTERN NORTH DAKOTA AS PER THE LATEST DAY 1 OUTLOOK FROM THE
STORM PREDICTION CENTER. HOWEVER...IF STORMS DEVELOP THIS
AFTERNOON IN PARTS OF CENTRAL NORTH DAKOTA AS PER THE 4KM
WRF- NMM...THOSE TOO HAVE POTENTIAL TO BE STRONG TO SEVERE.

HEAVY RAIN COULD ACCOMPANY THE THUNDERSTORMS...ESPECIALLY
TONIGHT...AS PRECIPITABLE WATER VALUES INCREASE TO NEAR 1.75 INCHES
IN THE NORTHWEST PART OF THE STATE TONIGHT.

IN ADDITION TO THE THUNDERSTORM CONCERNS FOR TODAY /
TONIGHT...ANOTHER ISSUE WILL BE THE POTENTIAL FOR ADVISORY LEVEL
WINDS TODAY IN THE SOUTHWEST PART OF THE STATE. FORECAST SOUNDINGS
SUGGEST MIXING WILL BE DEEP WITH NEAR 40 KTS OF WIND AVAILABLE
AT H8. THE LATEST GFS NUMERICAL GUIDANCE FOR BAKER MONTANA
FORECASTS SUSTAINED WIND SPEEDS NEAR 29 KTS...SO AFTER
COORDINATION WITH WFO RAPID CITY HAVE OPTED TO ISSUE A WIND
ADVISORY IN PARTS OF SOUTHWEST NORTH DAKOTA FOR TODAY INTO THIS
EVENING.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 351 AM CDT WED JUN 19 2013

THE MAIN FORECAST ISSUES THROUGH THE LONG TERM PERIOD ARE SEVERE
WEATHER POTENTIAL AND TIMING ISSUES THROUGH FRIDAY.

STRONG TO POTENTIALLY SEVERE STORMS FROM AN ORGANIZED STORM
CLUSTER MAY PERSIST ACROSS NORTHERN COUNTIES THURSDAY MORNING.
OTHERWISE...STORM RE-INTENSIFICATION IS EXPECTED DURING THE
AFTERNOON/EVENING HOURS ALONG A STRONG MOISTURE CONVERGENCE AXIS
WITH DEWPOINTS IN THE UPPER 60S AND PWAT VALUES APPROACHING 2
INCHES. ISOLATED FLASH FLOODING WILL BE A CONCERN...ALONG WITH
HAIL/DAMAGING WIND THREAT...ESPECIALLY ALONG AND EAST OF HIGHWAY
83. CONTINUE TO FAVOR SLOWER ECMWF/GFS SOLUTIONS REGARDING HIGHER
POPS ACROSS THE EAST FOR THURSDAY NIGHT. THE TIMING ISSUES PERSIST
INTO FRIDAY...AND AGAIN HAVE LEANED TOWARD MORE WIDESPREAD STORMS
PER THE ECMWF. TOTAL RAINFALL AMOUNTS OF 1 TO 2 INCHES...ISOLATED
HIGHER...WILL BE POSSIBLE ACROSS THE NORTH THROUGH FRIDAY NIGHT.
THE CLOSED UPPER LOW ACROSS THE PACIFIC NORTHWEST IS EXPECTED TO
FINALLY MOVE THROUGH THE NORTHERN PLAINS OVER THE
WEEKEND...SUPPORTING ADDITIONAL ROUNDS OF SHOWERS AND
THUNDERSTORMS. NEAR SEASONAL TEMPS ARE EXPECTED THROUGH THE
WEEKEND...FOLLOWED BY SOME WARMING EARLY NEXT WEEK.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 954 AM CDT WED JUN 19 2013

AT 10 AM CDT...SURFACE TROUGH AND ASSOCIATED WARM FRONTAL
BOUNDARY ACROSS SOUTHEAST MONTANA WILL BE THE FOCUS FOR
SCATTERED THUNDERSTORM DEVELOPMENT LATER THIS AFTERNOON...BUT
MAINLY TONIGHT AND THURSDAY. VFR CONDITIONS WILL PREVAIL ACROSS
THE REGION. WHILE THERE WILL BE A THREAT OF THUNDERSTORMS AT ALL TAF
SITES...MAIN FOCUS FOR THUNDERSTORMS WILL BE NORTH AFTER 02Z...
IMPACTING KISN-KMOT AFTER 02Z.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 9 PM MDT THIS EVENING FOR NDZ031>033-040-041-
043-044.

&&

$$

UPDATE...WAA
AVIATION...WAA