Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 222034
AFDBIS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
334 PM CDT TUE APR 22 2014

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 335 PM CDT TUE APR 22 2014

GUSTY SOUTHEASTERLY WINDS WILL CONTINUE ACROSS WESTERN AND
CENTRAL NORTH DAKOTA LATER THIS AFTERNOON AND OVERNIGHT. THE
MODELS HAVE BEEN PERFORMING POORLY WITH RESPECT TO AFTERNOON
DEWPOINTS (TOO HIGH). AS A RESULT...MANUALLY ADJUSTED THE
AFTERNOON DEWPOINTS DOWN BASED ON THE CURRENT OBS/TRENDS. THE
COMBINATION OF HIGH WINDS AND LOW RELATIVE HUMIDITIES CONTINUE TO
GENERATE A VERY HIGH FIRE DANGER OVER WESTERN AND CENTRAL NORTH
DAKOTA THIS AFTERNOON. DEWPOINT RECOVERY SHOULD BEGIN IN EARNEST
AFTER SUNSET AS LOW-LEVEL MOISTURE GETS DRAWN UP OVER THE STATE
AHEAD OF AN APPROACHING LONGWAVE TROUGH.

THE MEDIUM RANGE MODELS PROG THAT LIGHT RAIN SHOWERS WILL BECOME
LIKELY AFTER MIDNIGHT AHEAD OF THE AFOREMENTIONED APPROACHING
LONGWAVE TROUGH. THE MAIN BAND OF WARM AIR ADVECTION/CONVEYOR BELT
PRECIPITATION IS EXPECTED TO DEVELOP FROM THE JAMES RIVER BASIN
AND EXTEND NORTHWEST INTO MINOT AND NORTHWESTERN NORTH DAKOTA.
FURTHERMORE...MARGINAL MID-LEVEL LAPSE RATES COMBINED WITH
INCREASING UPPER LEVEL FORCING COULD GENERATE A SLIGHT CHANCE FOR
THUNDERSTORMS WEST AFTER MIDNIGHT. HOWEVER...NO ORGANIZED SEVERE
WEATHER IS EXPECTED.

BY WEDNESDAY...THE MAIN PRECIPITATION BAND IS FORECAST TO LIFT
NORTHEAST AS THE ATTENDANT SURFACE TROUGH AXIS LIFTS NORTHEAST
ACROSS THE STATE. AGAIN...MARGINAL CONVECTIVE PARAMETERS WARRANT
AT LEAST A SLIGHT CHANCE OF THUNDERSTORMS MENTION OVER CENTRAL AND
EASTERN NORTH DAKOTA...MAINLY ALONG THE BOUNDARY AS IT PUSHES
ACROSS THE STATE. THIS IS CONSISTENT WITH THE SPC DAY 2 OUTLOOK.

MARGINAL WIND ADVISORY CRITERIA MAY DEVELOP OVER SOUTHWESTERN
NORTH DAKOTA WEDNESDAY AFTERNOON. WILL HOLD OFF ON ISSUING ANY
WIND HEADLINES FOR THIS UPDATE AND WILL LET LATER SHIFTS DECIDE.

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 335 PM CDT TUE APR 22 2014

TWO VIGOROUS SYSTEMS WILL INFLUENCE THE WEATHER ACROSS WESTERN AND
CENTRAL NORTH DAKOTA IN THE LONG TERM PERIOD.

SYSTEM 1...

A WAVE MOVING ACROSS THE NORTHWEST U.S. AND SOUTHWEST
CANADA IS EXPECTED TO DEVELOP A CLOSED UPPER LEVEL CIRCULATION OVER
SOUTHERN BRITISH COLUMBIA/ALBERTA ON WEDNESDAY AND TRACK SLOWLY EAST
ALONG THE INTERNATIONAL BORDER THROUGH FRIDAY.

A SURFACE WARM FRONT IS FORECAST TO BE NEAR THE DEVILS LAKE AND
JAMES RIVER BASIN BY WEDNESDAY EVENING...WITH SOUTHEAST WINDS AHEAD
OF THE WARM FRONT AND WEST WINDS BEHIND IT. SCATTERED TO NUMEROUS
SHOWERS DURING THE DAY WEDNESDAY SHOULD BE MAKING THEIR WAY ALONG
AND AHEAD OF THE WARM FRONT...WITH A DRY SLOT BEHIND IT OVER
SOUTHWESTERN NORTH DAKOTA. THUS EXPECTING EVENING SCATTERED SHOWERS
NORTH THROUGH THE JAMES RIVER VALLEY...WITH MAINLY SLIGHT CHANCES OF
SHOWERS AFTER MIDNIGHT.

ON THURSDAY MORNING A SURFACE LOW ALONG THE NORTHERN BRANCH OF THE
WARM FRONT IS FORECAST TO BE SITUATED OVER SOUTHERN SASKATCHEWAN.
THIS LOW IS FORECAST TO MOVE SOUTHEAST ACROSS NORTH DAKOTA ON
THURSDAY...WITH A BAROCLINIC ZONE/BOUNDARY SETTING UP
NORTHWEST-TO-SOUTHEAST ACROSS THE STATE THURSDAY NIGHT. THIS
SCENARIO WILL BRING A CHANCE OF SHOWERS - BETTER CHANCES NORTH -
WITH THUNDERSTORMS POSSIBLE THURSDAY AFTERNOON.

LATE THURSDAY NIGHT AND FRIDAY A COLD FRONT MOVES SOUTH ACROSS THE
STATE...BRINGING A CHANCE OF RAIN OR SNOW SHOWERS - MAINLY NORTH IN
THE TURTLE MOUNTAINS...BUT WITH LITTLE OR NO SNOW ACCUMULATIONS.

SYSTEM 2...

DURING THIS TIME THE NEXT STRONG SYSTEM IS TAKING SHAPE OVER THE
WESTERN U.S. MODEL UNCERTAINTY INCREASES AS WE HEAD INTO THE WEEKEND
BUT IT APPEARS THAT THE UPPER LEVEL FLOW IS TRENDING SLOWER WITH A
BLOCKING PATTERN SETTING UP OVER THE CENTRAL PORTION OF THE COUNTRY.
THIS BLOCK MAINLY KEEPS A COLD HIGH PRESSURE SYSTEM OVER HUDSON BAY
WHILE A LARGE UPPER LEVEL LOW DEVELOPS ACROSS THE US ROCKIES AND
CLOSES OFF SOMEWHERE IN THE WESTERN/CENTRAL/SOUTHERN PLAINS. WILL
NEED TO KEEP AN EYE ON THE EVOLUTION OF THIS SYSTEM AS LATEST
DETERMINISTIC RUNS ARE COLDER AND WETTER ACROSS WESTERN AND CENTRAL
NORTH DAKOTA. UTILIZED A STRAIGHT MODEL BLEND FOR THE EXTENDED AND
THIS IS DEPICTING PRECIPITATION ACROSS MAINLY THE SOUTHWEST ON
SATURDAY...THEN SPREADING ACROSS MOST OF THE AREA SUNDAY THROUGH
MONDAY. WITH COLDER TEMPERATURES EXPECTED BY THE WEEKEND
PRECIPITATION CHANCES WERE MAINLY RAIN DURING THE AFTERNOON AND
EARLY EVENING...WITH A MIX OF RAIN AND SNOW DURING THE OVERNIGHT AND
EARLY MORNING HOURS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 115 PM CDT TUE APR 22 2014

VFR CONDITIONS WILL PREVAIL OVER WESTERN AND CENTRAL NORTH DAKOTA
THIS AFTERNOON AND EVENING. LIGHT RAIN SHOWERS WILL GRADUALLY
DEVELOP FROM SOUTH TO NORTH AFTER MIDNIGHT TONIGHT THROUGH THE END
OF THE TAF PERIOD. TEMPO MVFR VSBYS WILL BE POSSIBLE WITH THE
HEAVIEST ACTIVITY (MAINLY OVER KJMS BETWEEN 06Z-12Z).
HOWEVER...VFR VSBYS SHOULD BE PREVALENT. MVFR CIGS SHOULD DEVELOP
AREA WIDE AFTER SUNRISE WEDNESDAY. SOUTHEASTERLY WINDS WILL BE
GUSTY THROUGH THE TAF PERIOD...WITH GUSTS UP TO 30 KNOTS POSSIBLE.

&&

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

&&

$$

SHORT TERM...TM
LONG TERM...JV
AVIATION...TM






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