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000
FXUS63 KBIS 210609
AFDBIS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
109 AM CDT TUE MAY 21 2013

.UPDATE...

ISSUED AT 109 AM CDT TUE MAY 21 2013

MAIN UPDATE EARLY THIS MORNING WAS TO TRIM THE WESTERN EDGE OF THE
WIND ADVISORY WITH WINDS DECREASING ALONG TO WEST OF HIGHWAY 83.
OTHERWISE THE INHERITED FORECAST LOOKS GOOD WITH RAIN CONTINUING
MOST AREAS.


UPDATE ISSUED AT 1008 PM CDT MON MAY 20 2013

MAIN UPDATE THIS EVENING WAS TO ADJUST THE WIND ADVISORY. WINDS
ARE DIMINISHING QUICKLY IN THE NORTHWEST AND EXPECT WINDS
SOUTHWEST TO DROP SOON. THEREFORE WILL CANCEL THE ADVISORY IN THE
WEST. WILL KEEP IT GOING IN THE CENTRAL THROUGH 1 AM CDT. DID
EXTEND THE ADVISORY OVER EASTERN PORTIONS OF CENTRAL NORTH DAKOTA
THROUGH 7 AM BASED MAINLY ON RAP ANALYSIS KEEPING 40-45 KNOT WINDS
AT 925MB INTO THE EARLY MORNING HOURS.

UPDATE ISSUED AT 734 PM CDT MON MAY 20 2013

QUICK UPDATE JUST TO FRESHEN UP GRIDS NOT UPDATED WITH THE
EXPANSION OF THE WIND ADVISORY. NO CHANGES TO THE ADVISORY AT THIS
TIME. WITH NEXT UPDATE MAY NEED TO LOOK INTO EXTENDING EASTERN
COUNTIES THROUGH THE NIGHT. MADE SOME MINOR ADJUSTMENTS TO POPS
THROUGH THE EVENING.

UPDATE ISSUED AT 540 PM CDT MON MAY 20 2013

UPDATE LATE THIS AFTERNOON DUE TO STRONG WINDS. WILL EXTEND THE
WIND ADVISORY FARTHER SOUTH TO INCLUDE AREAS ALONG AND NORTH OF
INTERSTATE 94.

VERY STRONG WINDS ACROSS FAR NORTH CENTRAL NORTH DAKOTA LATE THIS
AFTERNOON WITH WIND GUST TO 48KTS RECORDED AT ROLLA. CURRENT GUSTS
HAVE SUBSIDED BACK TO AROUND 40-42 KNOTS. WILL CONTINUE TO MONITOR
FOR POSSIBLE HIGH WIND WARNING THIS EVENING.

LATEST RAP ANALYSIS SHOWS AROUND 40-45 KNOTS OF WIND AT 925 MB
THROUGH MID EVENING...MAINLY ALONG AND EAST OF THE HIGHWAY 83
CORRIDOR AND ALONG AND NORTH OF INTERSTATE 94. ALSO 850 KNOT WINDS
INCREASE EARLY THIS EVENING ACROSS MUCH OF CENTRAL NORTH DAKOTA.
AFTER COORDINATION WITH FGF...WILL EXTEND THE CURRENT WIND
ADVISORY FARTHER SOUTH TO ALONG AND NORTH OF INTERSTATE 94...AND
KEEP AN EYE ON WINDS ACROSS THE FAR NORTH CENTRAL...HOLDING OFF ON
A HIGH WIND WARNING AT THIS TIME.

OTHERWISE NO SIGNIFICANT CHANGES TO THE FORECAST.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 330 PM CDT MON MAY 20 2013

THE HIGHLIGHT OF THE SHORT TERM CONTINUES TO BE THE IMPACTS OF THE
ONGOING RAINFALL EVENT.

OVERALL THE GUIDANCE IS IN GOOD AGREEMENT...AND FOLLOWED A BLEND
OF THE 12 UTC GFS/GEM/ECMWF AND 15 UTC SREF FOR ALL FIELDS.
CURRENTLY THE STACKED LOW ACROSS FAR NORTHEAST SOUTH DAKOTA IS
EXPECTED TO SLOWLY PROPAGATE INTO CENTRAL MINNESOTA THROUGH
TUESDAY. WRAP AROUND RAINFALL IS EXPECTED TO SLOWLY DOWNTREND
THROUGH THE NIGHT AND INTO TUESDAY WITH AN ADDITIONAL ONE HALF TO
THREE QUARTERS OF AN INCH OF RAINFALL EXPECTED. SEE THE HYDROLOGY
DISCUSSION BELOW FOR DETAILS.

FOR THIS EVENING AND TONIGHT...DID MAINTAIN THE WIND ADVISORY FOR
THE WEST AND NORTH. THE WIND FIELD ACROSS THESE AREAS CONTINUES TO
STRENGTHEN WITH 40-45 KTS AT THE TOP OF A SHALLOW MIXED LAYER AS
DEPICTED BY THE 12 UTC NAM/GFS BUFR SOUNDINGS. THE STRONGEST WINDS
ARE EXPECTED ACROSS THE TURTLE MOUNTAINS WHERE GUSTS TO NEAR 50
MPH ARE POSSIBLE THROUGH EARLY EVENING.

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 330 PM CDT MON MAY 20 2013

THE MAIN FORECAST ISSUE THROUGH THE LONG TERM PERIOD WILL BE ONGOING
RIVER AND OVERLAND FLOODING CONCERNS. SEE HYDROLOGY DISCUSSION BELOW
FOR DETAILS. THEN ATTENTION TURNS TO THE UPCOMING WEEKEND AND THE
POSSIBILITY FOR SCATTERED THUNDERSTORMS AND POSSIBLE SEVERE WEATHER.

THERE IS FAIRLY GOOD MODEL AGREEMENT REGARDING THE POSITION AND
MOVEMENT OF THE CLOSED UPPER LEVEL LOW...ASSOCIATED WITH THE
PERSISTENT RAINS FOR THE PAST SEVERAL DAYS. THE UPPER LOW IS
FORECAST TO BE OVER THE SD/MN BORDER TUESDAY EVENING...THEN BECOME
MORE OF AN OPEN WAVE BY WEDNESDAY EVENING OVER IA/WI/IL AND THE
WESTERN GREAT LAKES. THIS SCENARIO WILL MEAN THE VERY HIGH/LIKELY
CHANCES OF RAIN TUESDAY NIGHT IN THE JAMES RIVER BASIN WILL LESSEN
TO SCATTERED IN NATURE BY WEDNESDAY. THE REST OF WESTERN AND CENTRAL
NORTH DAKOTA SHOULD SEE A DECREASE IN COVERAGE OF THE SHOWERS
TUESDAY NIGHT. SLIGHT CHANCES TO SCATTERED SHOWERS WEDNESDAY AS THE
SYSTEM MOVES EAST OF THE REGION.

BY WEDNESDAY EVENING AS THE UPPER LEVEL LOW/TROUGH MOVES EAST...A
WEAK UPPER LEVEL RIDGE WILL BUILD ACROSS THE NORTHERN PLAINS. THIS
WILL BE SHORT-LIVED AS ANOTHER LARGE UPPER LEVEL LOW/TROUGH SYSTEM
MOVES INTO THE PACIFIC NORTHWEST AND ROCKIES. THUS NO PRECIPITATION
MENTION FOR WEDNESDAY NIGHT THROUGH THURSDAY NIGHT.

FRIDAY THROUGH THE WEEKEND AND INTO MONDAY...THE UPPER LEVEL LOW
OVER THE ROCKIES IS FORECAST TO REMAIN IN PLACE...SETTING UP A
PROLONGED PERIOD OF SOUTHWESTERLY FLOW ALOFT FOR NORTH DAKOTA. THIS
WILL MEAN PERIODIC UPPER LEVEL SHORTWAVE ENERGY MOVING NORTHEASTWARD
THROUGH THE MEAN FLOW. AT THE SURFACE...THIS WILL RESULT IN BROAD
LOW PRESSURE ACROSS THE PLAINS...ALLOWING PLENTY OF GULF OF MEXICO
MOISTURE TO STREAM NORTHWARD. A PROLONGED LOW LEVEL JET AT H925-H850
WILL HELP TRANSPORT MOISTURE AND ENERGY NORTHWARD UP THE PLAINS.
THUS PERIODIC EPISODES OF SCATTERED THUNDERSTORMS WILL BE IN THE
FORECAST FRIDAY THROUGH THE MEMORIAL DAY WEEKEND.

WHILE TOO FAR OUT FOR MUCH CERTAINTY IN NARROWING DOWN SPECIFIC
AREAS OF CONCERN...SURFACE DEWPOINTS RISING INTO THE 50S BY FRIDAY
AND FORECAST CAPE DEVELOPING FROM THE SOUTHERN...CENTRAL...TO THE
NORTHERN PLAINS WOULD SUGGEST SOME SEVERE THUNDERSTORM ACTIVITY OVER
A BROAD AREA OF THE PLAINS FRIDAY AND SATURDAY. STAY TUNED FOR LATER
FORECASTS AND STORM PREDICTION CENTER OUTLOOKS FOR THE POTENTIAL FOR
SEVERE THUNDERSTORMS THIS COMING WEEKEND.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)

ISSUED AT 109 AM CDT TUE MAY 21 2013

LIGHT TO SOMETIMES MODERATE RAINFALL WILL CONTINUE OVER ALL
TERMINALS THROUGH THE TAF PERIOD WITH MVFR/IFR CIGS/VSBYS. WIND
GUSTS OF 30-40 KTS ARE POSSIBLE AT EASTERN TAF
SITES...KJMS...THROUGH THIS TUESDAY MORNING.

&&

.HYDROLOGY...
ISSUED AT 330 PM CDT MON MAY 20 2013

DID MAINTAIN THE FLOOD WATCH FOR ALL OF WESTERN AND CENTRAL NORTH
DAKOTA THROUGH TONIGHT. CALLS TO AREA EMERGENCY MANAGERS REVEAL THAT
FOR THE MOST PART...COUNTY AND TOWNSHIP ROAD IMPACTS ARE LIMITED.
HOWEVER...AS SOILS CONTINUE TO SATURATE...OVERLAND FLOOD CONCERNS
COULD INCREASE THROUGH THE NIGHT. FURTHERMORE...REPORTS HAVE BEEN
COMING IN OF WATER ENTERING BASEMENTS ACROSS THE AREA WITH THE
SATURATED GROUND. ADDITIONAL RIVER AND STREAM RISES ARE EXPECTED
OVER THE COMING DAYS. FOR THE MOST PART WITHIN BANK RISES ARE
ANTICIPATED. HOWEVER...THE SOURIS RIVER AT TOWNER IS EXPECTED TO
RISE ABOVE FLOOD STAGE AGAIN...THE PIPESTEM CREEK NEAR PINGREE IS
FORECAST TO RISE ABOVE MINOR FLOOD STAGE TOMORROW AFTERNOON WITH
THE WILLOW CREEK NEAR WILLOW CITY POSSIBLY APPROACHING FLOOD STAGE
BY WEDNESDAY EVENING.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH UNTIL 7 AM CDT /6 AM MDT/ THIS MORNING FOR
NDZ001>005-009>013-017>023-025-031>037-040>048-050-051.

WIND ADVISORY UNTIL 7 AM CDT THIS MORNING FOR NDZ004-005-012-013-
022-023-025-036-037.

&&

$$

UPDATE...NH
SHORT TERM...AYD
LONG TERM...JV
AVIATION...NH
HYDROLOGY...AYD