Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 280556
AFDBIS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
1256 AM CDT THU MAY 28 2015

.UPDATE...
ISSUED AT 1241 AM CDT THU MAY 28 2015

SEVERAL CHANGES WERE MADE FOR THIS UPDATE.

FIRST...PRECIPITATION IS FALLING APART AND MOVING OFF TO THE
NORTHEAST FASTER THAN PREVIOUSLY THOUGHT. THEREFORE...LOWERED
PRECIPITATION AMOUNTS AND CHANCES FOR THE EARLY MORNING HOURS.

SECOND...ADDED PATCHY FOG IN ACROSS THE WEST. WITH A VERY MOIST
AND CALM BOUNDARY LAYER THE LAST SEVERAL HRRR RUNS HAVE INDICATED
FOG BREAKING OUT ACROSS WESTERN NORTH DAKOTA THIS MORNING.

THIRD...LOWERED OVERNIGHT TEMPERATURES. WITH PRECIPITATION AND
CLOUDS MOVING OUT FASTER...CLEAR SKIES AND CALM WINDS HAVE ALLOWED
TEMPERATURES TO QUICKLY FALL ACROSS WESTERN NORTH DAKOTA.

UPDATE ISSUED AT 951 PM CDT WED MAY 27 2015

LIGHTNING RATES HAVE DECREASED CONSIDERABLY DURING THE PAST HOUR.
DROPPED THE THUNDERSTORM CHANCES AND WEST HIGH PROBABILITIES OF
SHOWERS CENTRAL.

UPDATE ISSUED AT 702 PM CDT WED MAY 27 2015

LATEST RADAR AND SATELLITE IMAGERY SHOWING A LINE OF SHOWERS AND
THUNDERSTORMS ACROSS WEST CENTRAL NORTH DAKOTA MOVING EAST MUCH
LIKE THE LATEST HRRR PROJECTS. BASED ON TRENDS BUMPED UP THE POPS
TO DEFINITE ACROSS CENTRAL NORTH DAKOTA. LOOKS LIKE A LULL IN
ACTIVITY FAR WEST WITH INCREASING CHANCES LATE TONIGHT WITH THE
APPROACHING COLD FRONT ON THURSDAY.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 310 PM CDT WED MAY 27 2015

THUNDERSTORM CHANCES THIS AFTERNOON THROUGH TONIGHT AND AGAIN
THURSDAY HIGHLIGHT THE SHORT TERM FORECAST.

WILL CONTINUE TO FOLLOW THE HIGH RESOLUTION CONVECTIVE  ALLOWING
GUIDANCE....NAMELY THE 17-19 UTC HRRR ITERATIONS AND 12 UTC WRF-
ARW/NMM FOR THE EVOLUTION OF CONVECTION THIS AFTERNOON AND THROUGH
THE NIGHT GIVEN THEIR GOOD HANDLING OF THE EVENT THUS FAR.
SCATTERED THUNDERSTORMS CONTINUE TO DEVELOP ALONG THE STATIONARY
FRONTAL BOUNDARY THIS AFTERNOON ARCHING FROM NORTHWEST NORTH
DAKOTA INTO THE JAMES RIVER VALLEY. MORE NUMEROUS THUNDERSTORMS
CONTINUE ACROSS WESTERN NORTH DAKOTA NEAR THE SURFACE TROUGH AXIS.
AS DEEP LAYER SHEAR INCREASES ACROSS THE SOUTHWEST WITH THE
APPROACH OF STRONGER FORCING...MARGINAL SEVERE HAIL AND WINDS ARE
POSSIBLE LATE THIS AFTERNOON AND EVENING. CONVECTION ACROSS THE
WEST IS EXPECTED TO CONGEAL THIS EVENING AS IT PROPAGATES INTO
CENTRAL NORTH DAKOTA...LIFTING INTO THE DEVILS LAKE BASIN AND RED
RIVER VALLEY BY 09-11 UTC.

FOR THURSDAY...SPC HAS EXPANDED THEIR MARGINAL THREAT AREA IN THE
DAY TWO OUTLOOK TO INCLUDE MOST OF CENTRAL NORTH DAKOTA. ML CAPE
VALUES OF 1000-1500 J/KG ARE ANTICIPATED IN THE VICINITY OF THE
PRE-FRONTAL TROUGH AHEAD OF THE STRONG COLD FRONT ENTERING THE
NORTHWEST PORTION OF THE STATE. HOWEVER...DEEP LAYER SHEAR FOR
SUPERCELLS IS MARGINAL...ON THE ORDER OF 20-30 KTS. THUS...A FEW
STRONG TO SEVERE STORMS ARE POSSIBLE WITH LARGE HAIL AND DAMAGING
WINDS BEING THE PRIMARY THREATS.

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 310 PM CDT WED MAY 27 2015

FROST POTENTIAL SATURDAY MORNING AND AN ACTIVE WEATHER PATTERN
NEXT WEEK HIGHLIGHT THE EXTENDED FORECAST.

A COOL FRIDAY IS EXPECTED IN THE WAKE OF THE AFOREMENTIONED COLD
FRONT IN THE SHORT TERM...WITH HIGHS IN THE UPPER 50S TO MID 60S.
AS A SURFACE RIDGE AXIS BUILDS INTO THE STATE ON FRIDAY...A COOL
FRIDAY NIGHT INTO SATURDAY MORNING IS POSSIBLE WITH LOWS IN THE 30S
AND POTENTIAL FROST. THEREAFTER...A RETURN TO AN ACTIVE WEATHER
PATTERN COMMENCES SUNDAY INTO WEDNESDAY AS THE UPPER LEVEL FLOW
PATTERN TRANSITIONS FROM ZONAL TO SOUTHWEST ALOFT. THIS WILL HAVE
TO BE MONITORED FOR SEVERE POTENTIAL. GIVEN GOOD AGREEMENT...A
BLEND OF THE 12 UTC DETERMINISTIC AND ENSEMBLE SUITES WERE USED
FOR MOST FIELDS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1241 AM CDT THU MAY 28 2015

RAIN SHOWERS HAVE ENDED AT ALL BUT KJMS. LATEST MODELS STILL
FORECAST MVFR/IFR CONDITIONS FORMING EARLY THIS MORNING AT
KDIK/KMOT/KISN. SOME UNCERTAINTY IF THIS WILL BE IFR OF MORE
MVFR. TRENDING TO THE MORE POSITIVE MVFR.

&&

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

$$

UPDATE...AJ
SHORT TERM...AYD
LONG TERM...AYD
AVIATION...AJ



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