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000
FXUS63 KBIS 241525
AFDBIS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
1025 AM CDT FRI MAY 24 2013

.UPDATE...
ISSUED AT 1020 CDT FRI MAY 24 2013

LOW PRESSURE OVER EASTERN MONTANA WILL MOVE INTO THE WESTERN
DAKOTAS TODAY. STRONG SOUTHEAST WINDS WILL CONTINUE OVER CENTRAL
NORTH DAKOTA...BUT DIMINISH IN THE WEST AS THE SURFACE LOW
APPROACHES. WILL CONTINUE THE WIND ADVISORY OVER THE SOUTH
CENTRAL.

MADE SOME SMALL ADJUSTMENTS TO POPS TODAY. WILL DELAY THE ONSET OF
SHOWERS A COUPLE OF HOURS AS ATMOSPHERE REMAINS STABLE AT THIS
TIME. LATEST MESO-SCALE MODELS ARE INDICATING AN AREA OF
INSTABILITY OVER THE FAR SOUTHWEST AND SOUTH CENTRAL LATER THIS
AFTERNOON BEHIND THE MAIN WAVE. WILL KEEP A SLIGHT CHANCE OF A
THUNDERSHOWER IN THE SOUTH CENTRAL THROUGH 01Z THIS EVENING.

UPDATE ISSUED AT 645 AM CDT FRI MAY 24 2013

INCREASED WIND SPEEDS IN THE GRIDS BY A FEW KNOTS TO MATCH UP A BIT
BETTER WITH THE CURRENT WIND ADVISORY. IT LOOKS AS IF THE WINDS
COULD FALL BELOW ADVISORY CRITERIA BY MID AFTERNOON.
HOWEVER...WILL LET THE DAY SHIFT DECIDE TO CUT IT SHORT OR CANCEL
IT EARLY IF WINDS DO INDEED TAPER OFF EARLIER THAN THE CURRENT
ADVISORY WOULD SUGGEST.

OTHERWISE...THE REMAINING WEATHER ELEMENTS ARE IN GOOD SHAPE. THE
UPDATED GRIDDED AND TEXT PRODUCTS HAVE BEEN SENT.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 439 AM CDT FRI MAY 24 2013

IN COLLABORATION WITH NEIGHBORS HAVE DECIDED TO ISSUE A WIND
ADVISORY FOR TODAY FOR THE SOUTH CENTRAL PART OF THE FORECAST
AREA. THIS WILL MATCH UP WELL IN LOCATION AND TIMING WITH NATIONAL
WEATHER SERVICE OFFICES IN RAPID CITY AND ABERDEEN SOUTH
DAKOTA...AND GRAND FORKS NORTH DAKOTA. A TIGHT PRESSURE GRADIENT
AHEAD OF A THERMAL RIDGE AXIS AND SURFACE TROUGH THAT WILL BE
PUSHING INTO THE WEST THIS MORNING...ALONG WITH A LOW LEVEL JET OF
CLOSE TO 50 MPH...WARRANTS THIS ADVISORY. DICKINSON WAS LEFT OUT
OF THE ADVISORY AS WINDS THERE WILL BE CLOSE TO ADVISORY CRITERIA
FOR A FEW HOURS EARLY THIS MORNING...THEN BEGIN DECREASING.

CONVECTION IN MONTANA...FROM BILLINGS TO JUST WEST OF GLASGOW WAS
MOVING STRAIGHT NORTH WITH NO RETURNS NEAR OR SOUTH OF THE
BISMARCK FORECAST AREA. A FEW ELEVATED RADAR RETURNS NORTH AND
EAST WERE ON THE NOSE OF THE LOW LEVEL JET AND WERE NOT REACHING
THE GROUND IN THE DRIER AIR.

NAM...AND HIGH RESOLUTION RAPID REFRESH MODEL...SHOW NO
CONVECTION IN THE FORECAST AREA UNTIL AFTERNOON...AND NOT MUCH AT
THAT UNTIL LATER DAY NORTH AND EAST. INSTABILITY INCREASES THERE
AND MODELS LOOK TO BE DOING A GOOD JOB HIGHLIGHTING THE MOST
LIKELY LOCATIONS FOR CONVECTION. ACTIVITY SHOULD BE ISOLATED TO
WIDELY SCATTERED...AND PARAMETERS DO NOT SUPPORT SEVERE WEATHER.

MODELS DO HANG ON TO CONTINUED SHOWER OR STORM CHANCE FAR EASTERN
AREAS WELL INTO THE NIGHT SO FOLLOWED THE PREVIOUS FORECAST LEAD
AND KEPT THE POPS GOING...FAR EAST.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 439 AM CDT FRI MAY 24 2013

THE MAIN FORECAST CONCERN FOR THE EXTENDED WILL BE THE SEVERE
POTENTIAL FOR SOUTHWESTERN NORTH DAKOTA SATURDAY AFTERNOON AND
EVENING. THE MEDIUM RANGE MODELS CONTINUE TO PROG AN UNSETTLED
WEATHER PATTERN OVER THE REGION THROUGH THE REMAINDER OF THE
EXTENDED. NO ONE MODEL HAS THE BEST HANDLE WITH THE TIMING AND
PLACEMENT OF PRECIP THROUGH THE PERIOD. AS A RESULT...CONTINUED TO
USE A BLEND OF SOLUTIONS FOR THIS FORECAST.

THE MEDIUM RANGE MODELS CONTINUE TO PROG A SHORTWAVE TO PUSH ACROSS
WESTERN AND CENTRAL NORTH DAKOTA SATURDAY. THIS UPPER DISTURBANCE
COMBINED WITH A DEEP GULF MOISTURE TAP...A VEERING WIND PROFILE
(35-40 KNOTS OF 0-6KM SHEAR)...AND INCREASING INSTABILITY
(APPROXIMATELY 1000 J/KG MUCAPE) WILL LEAD TO AN INCREASED CHANCE
FOR THUNDERSTORMS POSSIBLY BECOMING SEVERE OVER SOUTHWESTERN NORTH
DAKOTA. THE MAIN HAZARDS WILL BE ISOLATED LARGE HAIL AND DAMAGING
WINDS. GIVEN THE INCREASING CONFIDENCE AND THE DAY 2 SPC CONVECTIVE
OUTLOOK...WENT AHEAD AND INTRODUCED SEVERE THUNDERSTORM WORDING IN
THE SOUTHWESTERN ZONES FOR THE SATURDAY AFTERNOON/EVENING PERIOD.

A SIMILAR SYNOPTIC PATTERN IS PROGGED TO SET UP OVER THE REGION
SUNDAY. HOWEVER...DEEP LAYER SHEAR VALUES ARE FORECAST TO BE LESS
THAN SATURDAY`S VALUES. AS A RESULT...KEPT THE MENTION OF SEVERE
THUNDERSTORMS OUT OF THE FORECAST FOR SUNDAY.

SOUTHWESTERLY FLOW ALOFT WILL CONTINUE THROUGH THE REMAINDER OF THE
EXTENDED. THIS PATTERN WILL PROVIDE CHANCES FOR THUNDERSTORMS EACH
DAY NEXT WEEK. TEMPERATURES WILL BE ABOVE NORMAL...WITH HIGHS IN THE
LOW TO MID 70S ALL NEXT WEEK.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1020 AM CDT FRI MAY 24 2013

LOW LEVEL MOISTURE WILL BE INCREASING TODAY ON GUSTY SOUTHEAST
SURFACE WINDS. THIS COULD RESULT IN LOWER END VFR CEILINGS
DEVELOPING IN SOUTH DAKOTA AND SPREADING INTO NORTH DAKOTA. WITH A
TROUGH MOVING INTO THE WEST TODAY THERE IS A CHANCE OF SHOWERS AND
THUNDERSTORMS BUT THEY SHOULD BE ISOLATED TO WIDELY SCATTERED IN
COVERAGE. THE TROUGH AXIS IS FORECAST ON A KISN TO KDIK LINE AT
25/00Z.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 7 PM CDT /6 PM MDT/ THIS EVENING FOR
NDZ019>022-034>036-042-045>047-050.

&&

$$

UPDATE...TWH
SHORT TERM...JPM
LONG TERM...TM
AVIATION...RK