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000
FXUS63 KBIS 220207
AFDBIS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
907 PM CDT TUE MAY 21 2013

.UPDATE...
ISSUED AT 853 PM CDT TUE MAY 21 2013

ISENTROPIC LIFT PERSISTS ACROSS THE SOUTH AND WEST...WITH THE WEST
LIKELY GETTING SOME UPSLOPE COMPONENT AS WELL AS EASTERLY LOW
LEVEL WINDS CONTINUE TO PULL LOW LEVEL MOISTURE INTO THE REGION.
UPPED THE CHANCE OF RAIN SHOWERS TO LIKELY ACROSS PORTIONS OF THE
SOUTH FOR THE EVENING AND EARLY MORNING. SO FAR DO NOT SEE A FIRM
TREND ON CLEARING ACROSS THE NORTH YET. SO HAVE SLOWED THE
PROGRESSION OF CLEARING UNTIL LATER TONIGHT. THIS MAY CAUSE SOME
PROBLEMS WITH FOG FORMATION NORTH UNTIL LATE. UPSLOPE FLOW
CONTRIBUTING TO LIGHT FOG SOUTHWEST THIS EVENING.

UPDATE ISSUED AT 650 PM CDT TUE MAY 21 2013

AT 6 PM CDT...THE CLOUD SHIELD EXTENDS ACROSS ALL OF NORTH DAKOTA
EXCEPT THE FAR NORTHERN TIER OF COUNTIES WHERE BREAKS IN THE
OVERCAST ARE NOW FORMING. AFTER SUNSET THE EAST NORTHEAST FLOW OUT
OF CANADA WITH WARMER TEMPERATURES AND LOWER DEW POINTS WILL
FURTHER ERODE THE CLOUDS. WITH MINOT STILL REPORTED A LIGHT SHOWER
ADDED SPRINKLES FOR SEVERAL HOURS THIS EVENING ALONG AND NORTH OF
LAKE SAKAKAWEA EXCLUDING THE NORTHERN BORDER COUNTIES WHERE
CLEARING WILL DEFINITELY BE FOUND. ACROSS THE SOUTH HALF WILL
STILL SEE SCATTERED SHOWERS THIS EVENING FOLLOWED BY CLEARING
OVERNIGHT. WILL THE NORTH CLEARING BY MIDNIGHT...AND ABUNDANT
SURFACE MOISTURE PRESENT...AREAS OF FOG STILL LOOK REASONABLE.
TEMPERATURE TRENDS LOOK GOOD AND DID NOT TOUCH THEM WITH THIS
FORECAST.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 327 PM CDT TUE MAY 21 2013

THE HIGHLIGHT OF THE SHORT TERM IS THE END OF THE LONG DURATION
RAINFALL EVENT ACROSS THE AREA.

FOR TONIGHT...THE RAP THROUGHOUT THE DAY HAS HAD A GOOD HANDLE ON
THE STRATUS DECK ACROSS THE AREA..AND FOLLOWED ITS LATEST 19 UTC
RUN FOR CLOUD COVER THROUGH THE NIGHT WHICH ADVECTS DRIER AIR
SOUTHWEST AND SCOURS OUT THE STRATUS. DID ADD A MENTION OF FOG TO
THE NORTHWEST AND NORTH CENTRAL WHERE SKIES FIRST CLEAR TONIGHT
AND WINDS BECOME LIGHT...ALLOWING FOR GOOD RADIATIONAL COOLING
INTO THE UPPER 30S AND SATURATION IN LIGHT OF THE RECENT RAINFALL.

A QUIET WEDNESDAY IS FORECAST WITH A SURFACE RIDGE AXIS ACROSS THE
AREA. GIVEN GOOD MODEL AGREEMENT...USED A BLEND OF THE 12 UTC
GEM/GFS/NAM/ECMWF AND 15 UTC SREF FOR ALL FIELDS...WITH GENERALLY
SUNNY SKIES AND HIGHS IN THE 60S.

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 327 PM CDT TUE MAY 21 2013

BY WEDNESDAY NIGHT AN UPPER LEVEL SHORTWAVE RIDGE BETWEEN THE
EXITING LOW PRESSURE SYSTEM TO THE EAST...AND THE ESTABLISHED UPPER
LEVEL LOW OVER THE WEST COAST/ROCKIES...WILL BE SITUATED OVER THE
PLAINS OF NORTH AMERICA. AT THE SURFACE...COOL HIGH PRESSURE RIDGE
MOVING SOUTH FROM CANADA NOSES INTO THE DAKOTAS.

BY THURSDAY THE SURFACE PRESSURE GRADIENT INCREASES AS THE
INTENSIFYING SURFACE LOW OVER THE ROCKIES/LEE OF THE ROCKIES SETS UP
A STRONGER SOUTHERLY/SOUTHEASTERLY WIND FLOW ACROSS THE WESTERN
PLAINS. SOUTHEAST WINDS 20 TO 30 MPH CAN BE EXPECTED OVER THE
WESTERN THIRD OF NORTH DAKOTA.

FRIDAY THROUGH THE MEMORIAL DAY WEEKEND...THE LARGE UPPER LEVEL LOW
OVER THE ROCKIES SETS UP A SOUTHWEST FLOW ALOFT OVER NORTH
DAKOTA...AND A SERIES OF UPPER LEVEL IMPULSES WILL TRAVERSE
NORTHEASTWARD ACROSS THE DAKOTAS. THUS A CHANCE OF THUNDERSTORMS
THROUGHOUT THIS PERIOD.

FAIRLY SEASONABLE TEMPERATURES IN THE LONG TERM...WITH HIGHS IN THE
60S AND 70S AND LOWS IN THE 40S AND 50S.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 853 PM CDT TUE MAY 21 2013

CIRCULATION AROUND A LOW PRESSURE AREA IN MINNESOTA CAUSING LOW
LEVEL ISENTROPIC LIFT/UPSLOPE COMPONENTS MANIFESTING ITSELF AS
LOWER CEILINGS INTO THE LOW MVFR TO IFR CATEGORY FROM KJMS-KBIS-
KDIK...WITH KDIK LIKELY INTO THE LOW IFR THROUGH 10Z. AFTER 10Z
SHOULD SEE IMPROVING CONDITIONS TO MVFR THEN VFR AFTER 12Z.

&&

.HYDROLOGY...
ISSUED AT 327 PM CDT TUE MAY 21 2013

FLOOD WARNINGS CONTINUE FOR THE PIPESTEM CREEK NEAR PINGREE AND
THE FORECAST POINTS OF TOWNER...BANTRY AND WESTHOPE ON THE SOURIS.
CONTINUING TO MONITOR THE WINTERING RIVER NEAR KARLSRUHE AND THE
WILLOW CREEK NEAR WILLOW CITY WHICH MAY APPROACH FLOOD STAGE IN
THE NEXT 24-48 HOURS. HAVE HELD OFF ON A FLOOD WARNING FOR
NOW...AND WILL WATCH HOW THESE WATERWAYS RESPOND TO RUNOFF.

&&

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

$$

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