000
FXUS63 KFGF 212350
AFDFGF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND FORKS ND
650 PM CDT TUE MAY 21 2013

.UPDATE...
ISSUED AT 650 PM CDT TUE MAY 21 2013

THE WEATHER IS ON TRACK WITH THE CURRENT FORECAST AND NO CHANGES
PLANNED AT THIS TIME. THE MAIN CHALLENGE WILL BE CLEARING OF THE
CLOUDS FROM THE NORTH...AND WILL LOOK AT THIS IN MORE DETAIL WITH
THE NEXT UPDATE.

SEE THE HYDROLOGY SECTION FOR THE LATEST INFORMATION ON THE
RENWICK DAM SITUATION.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 329 PM CDT TUE MAY 21 2013

THE FOCUS TODAY WAS ON THE SERIOUS FLOODING SITUATION IN
NORTHEASTERN ND. GOOD NEWS IS THAT THE VERY LAST OF THE LIGHT
SHOWERS ARE MOVING THRU AND FROM 00Z WED TO 12Z FRI DRY WEATHER IS
FORECAST FOR THAT GRAFTON-WALHALLA-CAVALIER AREAS.

UPPER LOW NR SIOUX FALLS WILL CONTINUE TO DROP SOUTH AND THEN EAST
THE NEXT 24 HOURS ALLOWING FOR SLOW CLEARING NOW IN SOUTHERN
MANITOBA (PORTAGE-WINNIPEG) TO DROP INTO FAR NRN ND BY 12Z WED AND
THEN SOUTHWARD REACHING THE FAR SOUTHERN FCST AREA WED EVE. WILL
KEEP IN CHC POPS FOR PRECIP TONIGHT IN THE CNTRL-SOUTHERN FCST
AREA AND ONLY IN THE FAR SOUTH-SOUTHEAST WEDNESDAY MORNING-MIDDAY.

HIGH PRESSURE AND CLEAR-PARTLY CLOUDY SKY FOR WED NIGHT. A BIT
COOLER THAN AVERAGE. COULD BE SOME FOG WED NIGHT WITH LIGHT WINDS
AND CLEAR SKY DUE TO ALL THE WATER IN THE FIELDS AND DITCHES.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 329 PM CDT TUE MAY 21 2013

NICE DAY ON THURSDAY WITH LIGHT WINDS AND SUNSHINE THEN CLOUDS TO
INCREASE LATE THU NIGHT INTO FRIDAY FROM THE WEST AS THE NEXT
SHORT WAVE MOVES INTO THE HIGH PLAINS. WILL MAINTAIN SOME LOW POPS
FOR FRIDAY IN ERN ND AND THE VALLEY FOR SOME WARM ADV LIGHT RAIN
SHOWERS.

12 UTC GFS/ECMWF ARE IN GOOD OVERALL AGREEMENT FRIDAY NIGHT THROUGH
EARLY NEXT WEEK. BOTH SHOW A RIDGE ALOFT ALIGNED ACROSS THE EASTERN
DAKOTAS THROUGH SUNDAY...THEN BREAKING DOWN SOMEWHAT EARLY NEXT WEEK
AS ENERGY FROM A PACIFIC NORTHWEST TROUGH MOVES ALONG THE CANADIAN
BORDER. MEANWHILE...A NORTHWEST TO SOUTHEAST ORIENTED MID-LEVEL
THERMAL BOUNDARY STALLS ACROSS THE NORTHERN PLAINS...PROVIDING A
FOCUSING MECHANISM FOR SHOWERS AND THUNDERSTORMS. BEST CHANCE FOR
MEASURABLE RAIN APPEARS TO BE FRIDAY NIGHT AND THEN AGAIN SUNDAY
NIGHT THROUGH TUESDAY AS A COUPLE SHORT-WAVES ROTATE ACROSS THE HIGH
PLAINS AND PROVIDE ADDITIONAL LIFT FOR CONVECTIVE DEVELOPMENT. ALL
BLEND GUIDANCE HANDLES THIS WELL AND WILL KEEP CHANCE POPS THROUGH
MOST OF THE LONG TERM FORECAST. WITH ADVANCING WARM FRONT...WILL SEE
A GRADUAL WARMING TREND THROUGH THE PERIOD FROM THE MID 60S ON
SATURDAY TO THE MID 70S BY NEXT TUESDAY.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 650 PM CDT TUE MAY 21 2013

IFR/MVFR CIGS WILL CONTINUE TO SLOWLY MOVE TO THE SOUTH...WITH VFR
CIGS MOVING INTO THE REGION FROM THE NORTH...AND EVENTUALLY
CLEARING ON WEDNESDAY.

&&

.HYDROLOGY...
ISSUED AT 650 PM CDT TUE MAY 21 2013

RAIN SHOWERS WILL BE ON THE WANE FROM THIS EVENING THROUGH WEDNESDAY
ALLOWING RIVER FORECASTING TO BE MORE RUNOFF AS OPPOSED TO QPF
BASED.  RIVER FLOOD WARNINGS REMAIN IN EFFECT AT WALHALLA AND NECHE
ALONG THE PEMBINA RIVER WITH WALHALLA HAVING CRESTED EARLIER.

BIGGEST FORECAST CHANGE IS ALONG PARK RIVER AT GRAFTON WHERE THE
COPIOUS RAINFALL HAS TRIGGERED RAPID STAGE RISES TOWARD MAJOR AND
ULTIMATELY NEAR RECORD FLOOD LEVELS.

RIVER FLOOD WARNINGS ARE NOW IN EFFECT FOR MOST OF THE MAINSTEM RED
AS WELL AS THE SOUTHERN VALLEY MINNESOTA TRIBUTARIES TO THE RED.
THESE POINTS ARE ALL EXPECTED TO ACHIEVE MINOR FLOOD STAGE SAVE FOR
OSLO WHERE MODERATE FLOODING IS FORECAST.

AREAL FLOOD WARNINGS WILL BE IN EFFECT FOR PEMBINA...EASTERN
CAVALIER...AND WALSH COUNTIES THROUGH THURSDAY. BY THEN AREAL
FLOODING SHOULD BECOME LESS OF A CONCERN WITH A DEARTH OF
PRECIPITATION AND THE CHANCE FOR SOME DRYING WITH WARMER
TEMPERATURES.

THE FLASH FLOOD WATCH REMAINS IN EFFECT FOR PARTS OF PEMBINA COUNTY
AS HEAVY RAINFALL OVER THE PAST FEW DAYS HAS CAUSED FLOOD WATERS TO
APPROACH THE TOP OF THE SPILLWAY AT THE RENWICK DAM. WATER
REMAINS VERY HIGH AND IS BEING HELD BACK BY A CONSTRUCTED EARTHEN
LEVEE ON TOP OF THE DAM STRUCTURE. OFFICIALS CONTINUE TO MONITOR
THE DAM AND THE NEW CLAY LEVEE FOR ANY EROSION. THERE ARE SEVERAL
OLD DAMS TO THE WEST OF THE RENWICK DAM...AND WITH THE LARGE
AMOUNT OF WATER IN THE AREA THESE DAMS COULD FAIL. IF ONE OF THESE
OLDER DAMS TO THE WEST DID FAIL...THE TEMPORARY LEVEE ON TOP OF
THE RENWICK DAM WOULD NO LONGER BE ABLE TO HOLD BACK WATER...AND
FLOODING WOULD BE IMMINENT FOR THE CITIES OF AKRA...CAVALIER...AND
BATHGATE. THE PEMBINA COUNTY EMERGENCY MANAGEMENT ANTICIPATES A
POSSIBLE BREACH WITHIN THE NEXT 12 HOURS...AND HAVE ORDERED A
MANDATORY EVACUATION BEGINNING AT 700PM FOR THE AREA IMMEDIATELY
DOWNSTREAM OF THE RENWICK DAM...INCLUDING THE CITY OF CAVALIER.

&&

.FGF WATCHES/WARNINGS/ADVISORIES...
ND...FLASH FLOOD WATCH THROUGH WEDNESDAY AFTERNOON FOR NDZ008.

MN...NONE.
&&

$$

UPDATE...TG
SHORT TERM...RIDDLE
LONG TERM...RIDDLE/ROGERS
AVIATION...TG
HYDROLOGY...WJB/TG