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000
FXUS63 KBIS 211452
AFDBIS

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

.UPDATE...
ISSUED AT 953 AM CDT TUE MAY 21 2013

NO SIGNIFICANT CHANGES REQUIRED WITH THIS FORECAST UPDATE AS THE
TREND THROUGH THE REMAINDER OF THE DAY WILL BE A DECREASE IN
PRECIPITATION CHANCES FROM NORTH TO SOUTH AS THE SURFACE LOW
ACROSS EASTERN SOUTH DAKOTA PROPAGATES INTO SOUTHERN MINNESOTA.
ALL MODELS ARE IN GOOD AGREEMENT WITH A BLEND OF THE 00 UTC
GEM/ECMWF...09 UTC SREF...06 UTC GFS AND 12 UTC NAM UTILIZED FOR
TEMPERATURES AND POPS.

UPDATE ISSUED AT 640 AM CDT TUE MAY 21 2013

GRADIENT FLOW HAS DECREASED ACROSS CENTRAL NORTH DAKOTA AS A SURFACE
LOW OVER EASTERN SOUTH DAKOTA WEAKENS AND SHIFTS FARTHER TO THE
SOUTHEAST. AS A RESULT...CANCELLED THE WIND ADVISORY FOR THIS
UPDATE.

OTHERWISE...ONLY MODIFIED HOURLY SENSIBLE WEATHER GRIDS BASED ON
CURRENT OBS/TRENDS. NO MAJOR UPDATES WERE REQUIRED TO THE ONGOING
FORECAST. THE UPDATED GRIDDED AND TEXT PRODUCTS HAVE BEEN SENT.

&&

.SHORT TERM...(TODAY AND TONIGHT)

ISSUED AT 414 AM CDT TUE MAY 21 2013

FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE ONGOING
RAIN AND WIND ASSOCIATED WITH THE STORM SYSTEM OVER THE REGION.

CURRENTLY...LARGE STACKED LOW PRESSURE SYSTEM OVER THE NORTHERN
PLAINS...CENTERED OVER WESTERN SOUTH DAKOTA. SEVERAL EMBEDDED
VORTICITY MAXIMUMS/CYCLONIC CIRCULATIONS ROTATING AROUND/WITHIN
THE LARGE LOW. RAIN IS MORE SCATTERED IN NATURE THIS MORNING
COMPARED TO THE PAST FEW DAYS WITH MOST OBS REPORTING LIGHT
RAIN RATHER THAN MODERATE OR HEAVY. PRESSURE GRADIENT SLOWLY
DIMINISHING OVER MY EAST BUT AM STILL SEEING GUSTY WINDS AT ROLLA
AND RUGBY TO OVER 40 MPH. THUS WILL MAINTAIN THE WIND ADVISORY AS
IS EAST OF HIGHWAY 83 AND NORTH IF I94 WITH THIS FORECAST PACKAGE.

100KT JET STREAK SOUTHEAST OF THE LOW FROM EASTERN KANSAS
NORTHEAST INTO THE WESTERN GREAT LAKES REGION...ALONG WITH A
SOUTHERN STREAM S/WV TROUGH MOVING EAST ACROSS NORTHERN
TEXAS TODAY...WILL ALL HELP TO NUDGE THE UPPER LOW SLOWLY
SOUTHEAST BEGINNING THIS AFTERNOON...ALLOWING A RIDGE OF HIGH
PRESSURE OVER SOUTH CENTRAL CANADA TO BUILD SOUTHWARD INTO THE
NORTHERN PLAINS TONIGHT. SEVERAL MORE EMBEDDED WAVES ROTATING
AROUND THE LOW WILL STILL BRING LIGHT RAINFALL TO MOST LOCATIONS
THIS MORNING...BUT WILL SEE CHANCES DECREASE NORTH LATER
TODAY...WITH THIS TREND (DECREASING PRECIPITATION CHANCES FROM
NORTH TO SOUTH) CONTINUING TONIGHT. WITH LESS THAN A QUARTER OF AN
INCH OF ADDITIONAL RAINFALL NOW EXPECTED FROM THIS STORM
SYSTEM...WE OPTED TO CANCEL THE FLOOD WATCH WITH FURTHER
HYDROLOGIC IMPACTS EXPECTED TO BE MINIMAL.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 414 AM CDT TUE MAY 21 2013

LIGHT RAIN WILL CONTINUE TO TAPER OFF FROM NORTHWEST TO SOUTHEAST
WEDNESDAY AS HIGH PRESSURE BUILDS INTO WESTERN NORTH DAKOTA. DRY
CONDITIONS ARE EXPECTED AREA WIDE WEDNESDAY NIGHT AND WILL CONTINUE
THROUGH THURSDAY NIGHT AS A MID-LEVEL RIDGE AXIS CRESTS ACROSS THE
REGION. NEAR NORMAL TEMPERATURES ARE EXPECTED.

THE MEDIUM RANGE MODELS CONTINUE TO PROG AN UNSETTLED WEATHER
PATTERN TO DEVELOP OVER WESTERN AND CENTRAL NORTH DAKOTA FRIDAY
THROUGH THE WEEKEND...AND INTO MONDAY. SOUTHWESTERLY FLOW ALOFT WILL
DEVELOP AS AN UPPER LEVEL LOW SPINS OVER THE PACIFIC NORTHWEST.
PERIODIC ENERGY TRAVERSING THE MEAN FLOW ALOFT WILL GENERATE CHANCES
FOR THUNDERSTORMS. GIVEN THE TIMING UNCERTAINTY...CONTINUED TO BROAD
BRUSH A CHANCE FOR THUNDERSTORMS EACH DAY IN THE LATTER PART OF THE
EXTENDED. IT IS STILL TOO EARLY TO TRY AND TARGET WHICH DAY WILL
HAVE THE HIGHEST POTENTIAL FOR SEVERE WEATHER...IF ANY SEVERE
WEATHER DEVELOPS AT ALL. AS A RESULT...SIDED WITH THE SPC AND THINK
THE POTENTIAL FOR SEVERE WEATHER IS TOO LOW AT THIS TIME.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)

ISSUED AT 953 AM CDT TUE MAY 21 2013

LIGHT RAINFALL WILL CONTINUE OVER ALL TERMINALS TUESDAY MORNING
AND AFTERNOON WITH MVFR/IFR CIGS/VSBYS. DECREASING CLOUDS EXPECTED
NORTH LATE TUESDAY NIGHT AFTER 06Z FOR KMOT-KISN...ALONG WITH
DECREASING CHANCES FOR RAIN ALL TERMINALS. WIND GUSTS OF 30 KTS
STILL POSSIBLE AT KJMS THROUGH TUESDAY MORNING.


&&

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

$$

UPDATE...AYD
SHORT TERM...NH
LONG TERM...TM
AVIATION...AYD