Severe Thunderstorm Warning 259, NWS Bismarck, ND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
315 AM CDT SUN AUG 20 2006

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT...
FORECAST CONCERNS/HIGHLIGHTS IN THE SHORT TERM WILL BE CONVECTIVE
CHANCES THIS AFTERNOON AND TONIGHT...THEN AGAIN TUESDAY NIGHT.

CURRENTLY...SURFACE HIGH PRESSURE DRIFTING TO THE SOUTHEAST OUT OF
THE CWA UNDER MOSTLY CLEAR SKIES. A DEVELOPING SURFACE TROUGH OVER
SOUTH CENTRAL CANADA IS PUSHING SOUTHEAST AS WELL TOWARDS THE REGION
IN RESPONSE TO AN UPPER LEVEL SHORT WAVE SLIDING OVER CENTRAL
CANADA.

THE SURFACE TROUGH WILL CONTINUE ITS SOUTHEASTWARD TRACK
TODAY...MOVING THROUGH THE FORECAST AREA DURING THE AFTERNOON AND
TONIGHT. WILL SEE A CHANCE OF THUNDERSTORMS IN THE VICINITY OF THE
TROUGH WITH SURFACE FORCING AND ATMOSPHERIC INSTABILITY IN PLACE.
MUCAPE VALUES OF 1500-2500 J/KG WILL MAINLY BE ACROSS THE SOUTH
CENTRAL AND SOUTHEAST TODAY/TONIGHT WHERE THE BEST MOISTURE
ADVECTION WILL BE...AND HENCE THE BETTER CHANCES OF THUNDERSTORMS.
WILL KEEP IN SLIGHT CHANCE POPS THOUGH FOR ALL ZONES FOR THE
AFTERNOON WITH THE TROUGH PASSAGE...THEN CONFINE POPS TO THE SOUTH
CENTRAL AND SOUTHEAST AFTER 0Z AROUND SURFACE FORCING AND THE BEST
INSTABILITY. BIGGEST LIMITING FACTOR FOR STORMS WEST AND CENTRAL
WILL BE LACK OF SURFACE MOISTURE. ATTM MODELS ARE PUTTING THE WETTER
DEW POINTS SOUTHEAST...SO HAVE INCREASED POPS TO CHANCE DURING THE
EVENING HERE. ELSEWHERE...ELEVATED AFTERNOON STORMS ARE POSSIBLE
GIVEN STEEP MID LEVEL LAPSE RATES WITH GUSTY WINDS AND DRY LIGHTNING
THE PRIMARY THREATS. THE HAIL THREAT WILL INCREASE FOR ANY EVENING
STORMS THAT MAY DEVELOP...AGAIN MORE TOWARDS THE SOUTH AND EAST.
TEMPERATURES TODAY WILL BE NEAR TO ABOVE SEASONAL.

HIGH PRESSURE FILTERS IN BEHIND THE TROUGH TONIGHT INTO MONDAY...BUT
SOME UNSTABLE AIR REMAINS OVER THE FAR SOUTH DURING MONDAY
AFTERNOON. WILL KEEP IN SLIGHT CHANCE POPS DOWN THERE...THEN
REMOVE PRECIP CHANCES AFTER 0Z MONDAY NIGHT WITH STABLE AIR MOVING
OVER ALL ZONES. TEMPERATURES ON MONDAY WILL DROP FROM TODAY...TO A
LITTLE CLOSER TO SEASONAL NORMS WITH COOLER 850H TEMPS ALOFT.

FOR TUESDAY...A MORE DYNAMIC SURFACE TROUGH DEVELOPS WEST OF THE
STATE...CREATING BREEZY SOUTHEASTERLY WINDS AND INCREASED
INSTABILITY. GOOD WAA IN PLACE WITH DAYTIME TEMPERATURES RISING TO
WELL ABOVE NORMAL WITH 90S LOOKING PROBABLE WEST AND SOUTH CENTRAL.
ADDED SLIGHT CHANCE THUNDER FOR TUESDAY NIGHT WEST AND CENTRAL.
LOOKING LIKE THE SAME OLD SCENARIO OF CONVECTION FIRING OFF IN
MONTANA AND PUSHING EAST DURING THE EVENING AND OVERNIGHT HOURS.
WILL ALSO LEAVE IN POPS EAST AS SEVERAL MODELS CONSISTENT IN PUTTING
A VORT MAX THROUGH THE AREA.

.LONG TERM...WEDNESDAY THROUGH SATURDAY NIGHT...
WEDNESDAY CONTINUES TO LOOK LIKE THE BEST CHANCE FOR STORMS IN THE
LONG TERM...AND NOW WE CAN ADD FRIDAY TO THE BETTER CHANCE CATEGORY.
STRONG WARM ADVECTION AHEAD OF WEDNESDAY SYSTEM WITH SOUTH SURFACE
FLOW WILL PUSH DEWPOINTS ABOVE 60 CENTRAL AND EAST AND THAT WILL
DESTABILIZE THE ATMOSPHERE WITH LIFTED INDICES FORECAST LOWER THAN
-4 AND CAPES BETTER THAN 1500 J/KG.

AGREED WITH EAST / SOUTHEAST NEIGHBORS ON THURSDAY BEING A BREAK
BETWEEN SYSTEMS AND CUT POPS ADJACENT TO THEM.

LATEST MODEL RUN IS MORE DEFINITIVE WITH SHARPENING THE BROAD MID
LEVEL TROUGH IN THE WEST AND BRINGING IT THROUGH NORTH DAKOTA ON
FRIDAY FOLLOWED BY RIDGING FOR THE WEEKEND. HAVE INTRODUCED POPS FOR
FRIDAY.

TEMPERATURES THROUGH THE PERIOD...STRONG THERMAL RIDGING WEDNESDAY
WILL BE ENOUGH TO BOOST TEMPERATURES ABOVE 90 MOST AREAS FOLLOWED BY
AN END OF THE WEEK 75-85 RANGE. ABOVE SEASONAL AVERAGE SHOULD RETURN
FOR THE WEEKEND.

&&

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

NH/JPM

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE BISMARCK ND
449 AM CDT SUN AUG 20 2006

NDZ001>005-009>013-017>023-025-031>037-040>048-050-051-211000-
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-
449 AM CDT SUN AUG 20 2006 /349 AM MDT SUN AUG 20 2006/

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 SLIGHT CHANCE OF THUNDERSTORMS WEST AND CENTRAL THIS
AFTERNOON...THEN MORE SOUTH CENTRAL AND SOUTHEAST TONIGHT. SOME OF
THE STORMS THAT DEVELOP MAY REACH SEVERE THRESHOLDS WITH GUSTY
WINDS...ISOLATED DRY LIGHTNING...AND HAIL BEING THE MAIN THREATS.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

THERE IS A CHANCE OF THUNDERSTORMS TUESDAY NIGHT THROUGH THURSDAY
NIGHT. SOME THUNDERSTORMS WILL MOST LIKELY BE SEVERE DURING THIS
TIME PERIOD.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED.

NH