Hail and Damaging Winds in North Dakota, August 9, 2010

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
246 PM CDT MON AUG 9 2010

.SYNOPSIS...AN ACTIVE WEATHER PATTERN THROUGH THE WEEK AS BROAD
RIDGING OVER THE CENTRAL US IS PUSHED SOUTHWARD BY MULTIPLE
DISTURBANCES EJECTING OUT OF A TROUGH ALONG THE WEST COAST.
SEVERAL ROUNDS OF THUNDERSTORMS ARE POSSIBLE THROUGH THE WEEK AS
THE TROUGH PUSHES EASTWARD SIGNALING A PATTERN SHIFT BY WEEKS END.

&&

.SHORT TERM...TONIGHT THROUGH THURSDAY NIGHT...
MODELS CONTINUE TO BE IN GOOD AGREEMENT THROUGH THE PERIOD.
CHANCES OF THUNDERSTORMS REMAIN THE PRIMARY FORECAST CONCERN ALONG
WITH THE POTENTIAL FOR SEVERE WEATHER.

CURRENTLY...A WEAK FRONTAL FEATURE OR DRYLINE STRETCHES FROM A
SURFACE LOW IN MANITOBA SOUTHWESTWARD INTO EXTREME NORTHWESTERN NORTH
DAKOTA AND NORTHEAST MONTANA. SCATTERED SHOWERS CONTINUE ACROSS
NORTHWEST AND NORTH CENTRAL NORTH DAKOTA. AS OF 2PM CLOUD COVER HAS
LIMITED WARMING IN THESE ARES WITH TEMPERATURES IN THE LOWER 80S
WHILE TEMPERATURES ACROSS SOUTHERN NORTH DAKOTA ARE IN THE LOWER 90S.
DEWPOINTS ARE IN THE MID TO UPPER 60S AT ALL SITES WITH THE
EXCEPTION SOUTHWESTERN NORTH DAKOTA WHERE THEY ARE IN THE UPPER 50S.
ALOFT...BROAD UPPER RIDGING CONTINUES ACROSS THE CENTRAL US WITH A
TROUGH ALONG THE WEST COAST.

THE 500 HPA RIDGE IS SLOWLY MOVING EASTWARD TODAY AS UPPER LEVEL
FLOW TRANSITIONS FROM ZONAL TO MORE SOUTHWESTERLY ALLOWING SHORTWAVE
TO EJECT OUT OF THE WESTERN US TROUGH AND MOVE TOWARDS THE NORTHERN
PLAINS. THE MAIN SHORTWAVE OF CONCERN MOVING INTO CENTRAL IDAHO AND
EVIDENT. THIS SHORTWAVE IS SLOWLY MOVING NORTHEASTWARD INTO THIS
EVENING AND MOVING INTO THE NORTHERN PLAINS AROUND 06 UTC TUESDAY.
THE SHORTWAVE LINGERS OVER THE NORTHERN PLAINS INTO TUESDAY
PROVIDING LIFT FOR SHOWER AND THUNDERSTORM ACTIVITY IN NORTH DAKOTA.
THE PREVIOUSLY MENTIONED SURFACE FRONT/WIND SHIFT LINE SLOWLY MOVES
THROUGH THE STATE AND NOT FULLY EXITING THE REGION UNTIL  12 UTC
WEDNESDAY. THIS VERY SLOW MOVING COLD FRONT WILL PROVIDE A FOCUS FOR
DEVELOPING THUNDERSTORMS THROUGH TUESDAY EVENING. THUNDERSTORMS ARE
EXPECTED TO DEVELOP THIS EVENING OVER MONTANA AND MOVE INTO WESTERN
NORTH DAKOTA BU 06 UTC. DESPITE WEAK SHEAR AND INSTABILITY SOME
THUNDERSTORMS MAYBE SEVERE EARLY. THE SPC PLACES WESTERN AND CENTRAL
NORTH DAKOTA UNDER SLIGHT RISK THIS EVENING WITH CENTRAL NORTH
DAKOTA IN SLIGHT RISK FOR TUESDAY. INSTABILITY AND SHEAR INCREASE
SLIGHTLY FOR TUESDAY INCREASING THE SEVERE WEATHER POTENTIAL.

THE SHORTWAVE LIFTS INTO CANADA BY 00 UTC WEDNESDAY ALLOWING THE
STRONG CENTRAL US RIDGE TO REBOUND OVER THE NORTHERN PLAINS.
HOWEVER...WAVES EJECTING OUT OF THE WESTERN US TROUGH CONTINUE TO
MOVE TOWARDS THE NORTHERN PLAINS BRINGING A CONTINUE RISK OF SHOWERS
AND THUNDERSTORMS. DURING THE DAY ON THURSDAY THE WESTERN US TROUGH
BEGINS TO MOVE EASTWARD ONCE AGAIN INCREASING CHANCES OF
PRECIPITATION BY THURSDAY NIGHT.

TEMPERATURES ARE EXPECTED TO BE COOLER ON TUESDAY WITH CLOUD COVER
AND ON GOING  PRECIPITATION. HOWEVER THE HOT AND HUMID CONDITIONS
RETURN TO THE NORTHERN PLAINS FOR WEDNESDAY AND THURSDAY AHEAD OF
THE NEXT SYSTEMS. TEMPERATURES RETURN IN THE LOWER TO MID 90S FOR
THE WEDNESDAY AND THURSDAY WITH OVERNIGHT LOWS IN THE LOWER 60S.

.LONG TERM...FRIDAY THROUGH MONDAY
AN UPPER LEVEL TROUGH WILL COVER CENTRAL CANADA AND THE NORTHERN
PLAINS OF THE US ON FRIDAY.  THE TROUGH WILL MOVE SLOWLY EAST
THROUGH MONDAY.  INITIALLY SHORT WAVES MOVING AROUND THE TROUGH
WILL BRING A CHANCE OF THUNDERSTORMS TO THE AREA...BUT AS THE TROUGH
MOVES EAST HIGH PRESSURE WILL MOVE DOWN INTO THE AREA FROM CANADA
AND THE CHANCE OF PRECIP WILL DECREASE LEAVING THE FORECAST AREA IN
A DRIER AIRMASS.

&&

.AVIATION...A WEAK SURFACE FRONT OR BOUNDARY SITS OVER EASTERN MONTANA THIS
AFTERNOON WITH WEAK SHOWERS OVER MAINLY NORTH CENTRAL NORTH DAKOTA
IN THE VICINITY OF KISN AND KMOT. VFR CONDITIONS PREVAIL AT ALL TAF
SITES WITH CEILINGS GENERALLY ABOVE 12KFT.

A DISTURBANCE LIFTING OUT OF THE GREAT BASIN THIS AFTERNOON AND
EVIDENT ON WATER VAPOR IS EXPECTED TO HELP INITIATE THUNDERSTORMS
MAINLY AFFECTING KISN...KMOT...AND KDIK AFTER 00 UTC THIS EVENING.
OCCASIONAL MVFR CEILINGS ARE POSSIBLE IN THUNDERSTORMS THIS EVENING
BUT VFR CEILINGS SHOULD CONTINUE THROUGH THE PERIOD. SOME
THUNDERSTORMS MAYBE SEVERE THIS EVENING. SCATTERED THUNDERSTORMS ARE
POSSIBLE ACROSS ALL OF WESTERN AND CENTRAL NORTH DAKOTA AFTER 12 UTC
TUESDAY.

&&

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

HW/DC/TSW

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE BISMARCK ND
544 AM CDT MON AUG 9 2010

NDZ001>005-009>013-017>023-025-031>037-040>048-050-051-101045-
DIVIDE-BURKE-RENVILLE-BOTTINEAU-ROLETTE-WILLIAMS-MOUNTRAIL-WARD-
MCHENRY-PIERCE-MCKENZIE-DUNN-MERCER-OLIVER-MCLEAN-SHERIDAN-WELLS-
FOSTER-GOLDEN VALLEY-BILLINGS-STARK-MORTON-BURLEIGH-KIDDER-
STUTSMAN-SLOPE-HETTINGER-GRANT-BOWMAN-ADAMS-SIOUX-EMMONS-LOGAN-
LA MOURE-MCINTOSH-DICKEY-
544 AM CDT MON AUG 9 2010 /444 AM MDT MON AUG 9 2010/

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTH CENTRAL
NORTH DAKOTA...NORTHWEST NORTH DAKOTA...SOUTH CENTRAL NORTH
DAKOTA...SOUTHEAST NORTH DAKOTA AND SOUTHWEST NORTH DAKOTA.

.DAY ONE...TODAY AND TONIGHT

THERE IS A CHANCE OF THUNDERSTORMS TODAY...AND A GOOD CHANCE OF
THUNDERSTORMS TONIGHT. SOME STORMS MAY BE SEVERE WITH LARGE HAIL
AND DAMAGING WINDS.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

THERE IS A GOOD CHANCE OF THUNDERSTORMS TUESDAY...SOME POSSIBLY
SEVERE. A SLIGHT CHANCE OF THUNDERSTORMS WEDNESDAY...THEN AN
ACTIVE WEEK CONTINUES WITH A CHANCE OF THUNDERSTORMS THURSDAY AND
FRIDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTERS MAY BE NEEDED THIS AFTERNOON AND TONIGHT.

JV