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000
FXUS63 KBIS 222324
AFDBIS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
624 PM CDT TUE JUL 22 2014

.UPDATE...
ISSUED AT 609 PM CDT TUE JUL 22 2014

SEVERE THREAT CONTINUES OVER FAR SOUTHWESTERN NORTH DAKOTA IN AREA
OF STRONGEST INSTABILITY. FURTHER NORTH...STILL EXPECT SOME STORMS
MAY DEVELOP THOUGH INSTABILITY TAPERS OFF...THUS SEVERE THREAT IS
MUCH LOWER.

UPDATE ISSUED AT 425 PM CDT TUE JUL 22 2014

UPDATED FOR STORM PREDICTION CENTER ISSUING A SEVERE THUNDERSTORM
WATCH FOR 4 SOUTHWESTERN COUNTIES OF NORTH DAKOTA: BILLINGS...SLOPE
BOWMAN...AND GOLDEN VALLEY COUNTIES. WATCH IN EFFECT UNTIL 10 PM
MDT.

RAISED CHANCES OF THUNDERSTORMS AND MENTIONED SEVERE STORMS
POSSIBLE.

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 315 PM CDT TUE JUL 22 2014

FORECAST ISSUES TODAY ARE THUNDERSTORM CHANCES TONIGHT AND
WEDNESDAY.

CURRENTLY...HIGH PRESSURE WAS CENTERED OVER CENTRAL
SASKATCHEWAN/MANITOBA WITH THE HIGH AXIS EXTENDING SOUTHWARD ACROSS
THE CENTRAL DAKOTAS. WEAK LOW PRESSURE WAS OVER THE FRONT RANGE. AT
UPPER LEVELS...A LOW PRESSURE CENTER WAS OVER THE EASTERN PACIFIC
OFF THE COAST OF BRITISH COLUMBIA...WITH A RIDGE OVER THE FRONT
RANGE. A WEAK UPPER LEVEL IMPULSE WAS MOVING NORTHEASTWARD ACROSS
NORTHEASTERN MONTANA...ASSOCIATED WITH A LINE OF SHOWERS AND
ISOLATED THUNDERSTORMS ORIENTED WEST-TO-EAST ACROSS NORTHEASTERN
MONTANA.

FOR TONIGHT...WILL KEEP A SLIGHT CHANCE MENTION OF THUNDER IN FAR
WESTERN NORTH DAKOTA DUE TO THE AFOREMENTIONED UPPER LEVEL IMPULSE.
THEN A THERMAL RIDGE AXIS BUILDS FARTHER NORTH JUST WEST OF THE
STATE LINE...AND WILL KEEP OUT ANY MENTION OF CHANCES OF
PRECIPITATION FOR THE REST OF THE NIGHTTIME HOURS.

ON WEDNESDAY...THE THERMAL RIDGE CONTINUES TO BUILD OVER
MONTANA/WYOMING...AND AN UPPER LEVEL IMPULSE MOVING INTO WESTERN
NORTH DAKOTA DURING THE MID/LATE AFTERNOON HAS A CHANCE TO SET OFF
SHOWERS/THUNDER OVER WESTERN NORTH DAKOTA DURING THE AFTERNOON HOURS.

EXPECTING LOWS TUESDAY NIGHT 55 TO 60 WITH HIGHS WEDNESDAY FROM THE
UPPER 70S IN THE NORTH CENTRAL TO NEAR 90 IN THE FAR SOUTHWEST.

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 315 PM CDT TUE JUL 22 2014

FOCUS OF THE LONG TERM WILL BE A SLIGHT RISK FOR SEVERE WEATHER
ON THURSDAY AND TIMING AN UPPER LEVEL LOW MOVING ACROSS SOUTHERN
CANADA.

LOW PRESSURE MOVING ACROSS SOUTHERN ALBERTA WILL PRODUCE ACTIVE
WEATHER FOR MUCH OF THE CWA...THURSDAY INTO FRIDAY MORNING. THE 12Z
RUN OF THE GFS/NAM MODELS HAVE BETWEEN 2000 AND 3000 J/KG OF CAPE IN
WESTERN AND CENTRAL PORTIONS OF THE STATE. SPC HAS PLACED THOSE
AREAS IN A SLIGHT RISK OF SEVERE THUNDERSTORMS. THE 12Z SUITE
SUPPORTS THUNDERSTORM DEVELOPMENT WITH A SHOWALTER AVERAGE OF -5C
AND UPPER LEVEL LAPSE RATES BETWEEN 7.5 AND 8.5 C/KM...SUPPORTING
MORE ROBUST THUNDERSTORMS.

CHANCES FOR SHOWERS AND THUNDERSTORMS WILL PERSIST INTO SATURDAY AND
SUNDAY...AS THE LOW CONTINUES ACROSS SASKATCHEWAN AND EVENTUALLY
SOUTHEASTWARD INTO THE NORTHERN PLAINS. THE EXACT TIMING OF
WHEN/WHERE THE LOW WILL TRACK SOUTHEAST IS UNCERTAIN AT THIS
TIME...THOUGH MODELS ARE TRENDING TOWARDS THIS WEEKEND.

PERSISTENT RIDGING OVER THE SOUTHERN PLAINS WILL KEEP HIGH
TEMPERATURES IN THE WEST/SOUTHWEST ABOVE AVERAGE ON
THURSDAY....UPPER 80S AND LOWER 90S. THE TEMPERATURE RANGE THROUGH
THE REST OF THE EXTENDED WILL BE UPPER 70S TO MID 80S.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 315 PM CDT TUE JUL 22 2014

FORECAST ISSUES TODAY ARE THUNDERSTORM CHANCES TONIGHT AND
WEDNESDAY.

CURRENTLY...HIGH PRESSURE WAS CENTERED OVER CENTRAL
SASKATCHEWAN/MANITOBA WITH THE HIGH AXIS EXTENDING SOUTHWARD ACROSS
THE CENTRAL DAKOTAS. WEAK LOW PRESSURE WAS OVER THE FRONT RANGE. AT
UPPER LEVELS...A LOW PRESSURE CENTER WAS OVER THE EASTERN PACIFIC
OFF THE COAST OF BRITISH COLUMBIA...WITH A RIDGE OVER THE FRONT
RANGE. A WEAK UPPER LEVEL IMPULSE WAS MOVING NORTHEASTWARD ACROSS
NORTHEASTERN MONTANA...ASSOCIATED WITH A LINE OF SHOWERS AND
ISOLATED THUNDERSTORMS ORIENTED WEST-TO-EAST ACROSS NORTHEASTERN
MONTANA.

FOR TONIGHT...WILL KEEP A SLIGHT CHANCE MENTION OF THUNDER IN FAR
WESTERN NORTH DAKOTA DUE TO THE AFOREMENTIONED UPPER LEVEL IMPULSE.
THEN A THERMAL RIDGE AXIS BUILDS FARTHER NORTH JUST WEST OF THE
STATE LINE...AND WILL KEEP OUT ANY MENTION OF CHANCES OF
PRECIPITATION FOR THE REST OF THE NIGHTTIME HOURS.

ON WEDNESDAY...THE THERMAL RIDGE CONTINUES TO BUILD OVER
MONTANA/WYOMING...AND AN UPPER LEVEL IMPULSE MOVING INTO WESTERN
NORTH DAKOTA DURING THE MID/LATE AFTERNOON HAS A CHANCE TO SET OFF
SHOWERS/THUNDER OVER WESTERN NORTH DAKOTA DURING THE AFTERNOON HOURS.

EXPECTING LOWS TUESDAY NIGHT 55 TO 60 WITH HIGHS WEDNESDAY FROM THE
UPPER 70S IN THE NORTH CENTRAL TO NEAR 90 IN THE FAR SOUTHWEST.

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 315 PM CDT TUE JUL 22 2014

FOCUS OF THE LONG TERM WILL BE A SLIGHT RISK FOR SEVERE WEATHER
ON THURSDAY AND TIMING AN UPPER LEVEL LOW MOVING ACROSS SOUTHERN
CANADA.

LOW PRESSURE MOVING ACROSS SOUTHERN ALBERTA WILL PRODUCE ACTIVE
WEATHER FOR MUCH OF THE CWA...THURSDAY INTO FRIDAY MORNING. THE 12Z
RUN OF THE GFS/NAM MODELS HAVE BETWEEN 2000 AND 3000 J/KG OF CAPE IN
WESTERN AND CENTRAL PORTIONS OF THE STATE. SPC HAS PLACED THOSE
AREAS IN A SLIGHT RISK OF SEVERE THUNDERSTORMS. THE 12Z SUITE
SUPPORTS THUNDERSTORM DEVELOPMENT WITH A SHOWALTER AVERAGE OF -5C
AND UPPER LEVEL LAPSE RATES BETWEEN 7.5 AND 8.5 C/KM...SUPPORTING
MORE ROBUST THUNDERSTORMS.

CHANCES FOR SHOWERS AND THUNDERSTORMS WILL PERSIST INTO SATURDAY AND
SUNDAY...AS THE LOW CONTINUES ACROSS SASKATCHEWAN AND EVENTUALLY
SOUTHEASTWARD INTO THE NORTHERN PLAINS. THE EXACT TIMING OF
WHEN/WHERE THE LOW WILL TRACK SOUTHEAST IS UNCERTAIN AT THIS
TIME...THOUGH MODELS ARE TRENDING TOWARDS THIS WEEKEND.

PERSISTENT RIDGING OVER THE SOUTHERN PLAINS WILL KEEP HIGH
TEMPERATURES IN THE WEST/SOUTHWEST ABOVE AVERAGE ON
THURSDAY....UPPER 80S AND LOWER 90S. THE TEMPERATURE RANGE THROUGH
THE REST OF THE EXTENDED WILL BE UPPER 70S TO MID 80S.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 609 PM  CDT TUE JUL 22 2014

STRONG TO SEVERE THUNDERSTORMS WITH VERY LARGE HAIL AND STRONG
WIND GUSTS WILL REMAIN POSSIBLE OVER FAR SOUTHWESTERN NORTH DAKOTA
THROUGH MID-EVENING. ISOLD-SCT THUNDERSTORMS REMAIN POSSIBLE
THROUGH THE EVENING OVER THE REMAINDER OF WESTERN NORTH DAKOTA.
OTHERWISE...VFR CONDITIONS ARE EXPECTED.

&&

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

$$

UPDATE...JJS
SHORT TERM...JV
LONG TERM...AC
AVIATION...JJS