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000
FXUS63 KFGF 220830
AFDFGF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND FORKS ND
330 AM CDT WED MAY 22 2013

.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 330 AM CDT WED MAY 22 2013

UPPER LOW FINALLY BEGINNING TO PULL AWAY FROM THE CWA AS IT WILL
SLOWLY MOVE SOUTHEASTWARD INTO IA TODAY. SFC HIGH PRESSURE HAS
STARTED TO NOSE DOWN OUT OF CANAD INTO THE NORTHERN PLAINS. MOST
OF THE PRECIP HAS MOVED SOUTH OF THE AREA ALTHOUGH A FEW SCATTERED
SHOWERS STILL LINGER IN THE SOUTHERN COUNTIES. THE NORTH HAS
CLEARED OUT COMPLETELY AND THERE HAS BEEN SOME PATCHY FOG
FORMATION AROUND CANDO AND LANGDON. HOWEVER...THERE IS STILL A
PRESSURE GRADIENT AND THINK THIS WILL KEEP FOG FROM BECOMING
WIDESPREAD AND DENSE. WILL KEEP A CLOSE EYE ON OBS THROUGH THE
EARLY MORNING HOURS.

SHOWERS AND CLOUDS WILL LINGER OVER THE SOUTHERN COUNTIES FOR MUCH
OF THE DAY BEFORE FINALLY CLEARING OUT BY LATE AFTERNOON. THIS
WILL KEEP TEMPS COOLER AND AROUND 60 WHILE THE NORTH WILL BE A BIT
WARMER. THE SFC HIGH WILL MOVE FURTHER DOWN FROM CANADA INTO THE
UPPER MS VALLEY TONIGHT. THIS SHOULD HELP THE NORTHER TIER ALONG WITH
EASTERN COUNTIES GET DOWN TO BELOW 40 DEGREES IN SOME AREAS.

THURSDAY SHOULD BE QUIET AND A BIT WARMER AS UPPER RIDGING BUILDS
OVER THE REGION. WITH SOME DECENT SUNSHINE KEPT HIGHS IN THE 60S
TO LOW 70S.

.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 330 AM CDT WED MAY 22 2013

THURSDAY NIGHT SOUTHEASTERLY WINDS STILL START PICKING UP OVER THE
WESTERN COUNTIES AS SFC HIGH PRESSURE OVER MN/WI ALONG WITH A
DEVELOPING LOW OVER MT CREATES A DECENT PRESSURE GRADIENT. THE
WINDS WILL HELP KEEP THE WESTERN COUNTIES FROM COMPLETELY
DECOUPLING AND STAY A BIT WARMER WHILE THE EAST WILL AGAIN DROP TO
AROUND 40 DEGREES. SOUTHEASTERLY WINDS WILL CONTINUE INTO FRIDAY
AND FRIDAY NIGHT AS A LEE TROUGH CONTINUES OVER THE WESTERN
PLAINS. MODELS ARE ALL IN FAIRLY DECENT AGREEMENT ON A WEAK
SHORTWAVE COMING OVER THE UPPER RIDGE AND SOME DECENT ISENTROPIC
LIFT PRODUCING SOME PRECIP FRIDAY AFTERNOON INTO FRIDAY NIGHT. AT
THIS POINT THE INSTABILITY SEEMS FAIRLY WEAK WITH SFC BASED CAPE
STAYING WEST OF OUR AREA AND ONLY A LITTLE BIT OF ELEVATED CAPE TO
WORK WITH. INCLUDED A CHANCE OF SHOWERS WITH ISOLATED
THUNDERSTORMS THROUGH FRIDAY NIGHT WITH BEST CHANCES IN OUR WEST.

SATURDAY-TUESDAY...00Z MODELS CONTINUE TO SUGGEST THE SYNOPTIC
PATTERN WILL BE DOMINATED BY LONGWAVE TROUGHING OVER THE WESTERN
US...WITH SOME DEGREE OF MID/UPPER LEVEL RIDGING INTO THE PLAINS
DURING MUCH OF THIS PERIOD. A SERIES OF WEAK UPPER LEVEL SHORTWAVE
TROUGHS EJECTING OUT OF THE BROADER TROUGH TO THE WEST WILL LEAD TO
BOUTS OF SHOWERS OR THUNDERSTORMS ACROSS THE REGION WITHIN THE LOW
TO MID-LEVEL WARM AIR ADVECTION ZONE ASSOCIATED WITH THE INDIVIDUAL
WAVES. WITH THIS TYPE OF PATTERN...CONFIDENCE IN THE
TIMING/PLACEMENT OF INDIVIDUAL WAVES IS LOW...SO CONTINUED TO CARRY
SOME POPS FOR MUCH OF THE PERIOD...ALTHOUGH MANY DRY HOURS ARE
EXPECTED.

THE 00Z GFS/ECMWF SUGGEST A TREND TO A MORE PREDOMINANT ACTIVE
SOUTHWEST FLOW PATTERN ACROSS THE PLAINS TOWARDS THE MIDDLE OF NEXT
WEEK...ALTHOUGH THE GFS IS MORE AMPLIFIED. THE GFS/ECMWF 925 MB
TEMPS RISE TO NEAR 20C ON TUESDAY...SUPPORTING HIGH TEMPS RISING
FROM MAINLY THE 60S OVER THE WEEKEND INTO THE 70S BY MONDAY OR
TUESDAY...WITH LOWS PRIMARILY IN THE 50S.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1148 PM CDT TUE MAY 21 2013

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. EXPECT GUSTY EAST/NORTHEAST WINDS WEDNESDAY
AFTERNOON.


&&

.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 RETENTION 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 FOR THE AREA
IMMEDIATELY DOWNSTREAM OF THE RENWICK DAM...INCLUDING THE CITY OF
CAVALIER.

&&

.FGF WATCHES/WARNINGS/ADVISORIES...
ND...FLASH FLOOD WATCH UNTIL 2 PM CDT THIS AFTERNOON FOR NDZ008.

MN...NONE.
&&

$$

SHORT TERM...JR
LONG TERM...JR/MAKOWSKI
AVIATION...TG
HYDROLOGY...WJB/TG/JH