Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 262352
AFDBIS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
552 PM CST WED NOV 26 2014

.UPDATE...
ISSUED AT 552 PM CST WED NOV 26 2014

NO MAJOR UPDATES WERE REQUIRED TO THE ONGOING FORECAST. THE MAIN
FORECAST PROBLEM WILL BE JUST HOW LOW TEMPERATURES WILL GET EAST
OF THE MISSOURI RIVER THIS EVENING BEFORE INCREASING CLOUD COVER
TAKES OVER AFTER MIDNIGHT.

JAMESTOWN DROPPED FROM ONE DEGREE TO 6 BELOW ZERO OVER THE LAST
HOUR. THE FORECAST LOW OF 12 BELOW ZERO LOOKS TO BE ON TARGET FOR
NOW...BUT MAY NEED TO BE LOWERED BASED ON EVENING OBS/TRENDS.
BOTTOM LINE...IT WILL BE COLD TONIGHT. AT LEAST THE WINDS WILL BE
RELATIVELY LIGHT.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 321 PM CST WED NOV 26 2014

THE FORECAST ISSUE TODAY WILL CENTER ON FREEZING RAIN/SLEET
ACROSS SOUTHWEST THROUGH THE WEST CENTRAL THURSDAY AND SNOW
ACCUMULATIONS NORTH CENTRAL NIGHT. SURFACE ARCTIC HIGH PRESSURE
CENTERED OVER MANITOBA INTO THE EASTERN DAKOTAS TONIGHT WILL SET
UP A GOOD OVERRUNNING MIXED PRECIPITATION EVENT ON THANKSGIVING
DAY INTO THE EVENING. THE SHALLOW ARCTIC AIR WILL BE ERODED
SOUTHWEST DURING THE DAY AS THE WARM FRONT APPROACHES AND MOVE
NORTH SO EXPECT A BRIEF PERIOD OF FREEZING RAIN SOUTHWEST BETWEEN
SUNRISE AND NOON. THEN THE MOST FAVORABLE AREA FOR FREEZING RAIN
EXTENDS FROM JUST SOUTH OF WILLISTON SOUTHEAST THROUGH GRANT
AND SIOUX COUNTIES. THE TIMING OF THIS AREA WILL BE FROM NOON
UNTIL THE EVENING HOURS. MEANWHILE...COLDER AIR OVER THE NORTH
WILL ASSURE THE PRECIPITATION IS SNOW...WITH 3 TO 4 INCHES EXPECTED
BY FRIDAY MORNING. FOR THIS A FREEZING RAIN ADVISORY HAS BEEN
ISSUED SOUTHWEST...AND A WINTER WEATHER ADVISORY NORTH FOR SNOW.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 321 PM CST WED NOV 26 2014

THE MAIN FORECAST PROBLEM TODAY IS THE POTENTIAL FOR A WINTRY MIX
ACROSS WESTERN NORTH DAKOTA ON FRIDAY.

12 UTC GFS/ECMWF/NAM/GEM GLOBAL ARE IN GOOD AGREEMENT THAT THE
AFOREMENTIONED WARM FRONT WILL BE STRETCHED ACROSS NORTHERN NORTH
DAKOTA AT THE START OF THE PERIOD. IT APPEARS THAT THE MAIN PUSH OF
COLD AIR ADVECTION WILL NOT REACH NORTH DAKOTA UNTIL LATE FRIDAY
EVENING...BASED ON MODEL CONSENSUS. THUS...ISENTROPIC LIFT AND A
SUFFICIENTLY STRONG MELTING LAYER ALOFT JUSTIFY KEEPING A WINTRY MIX
IN PLACE ACROSS PARTS OF THE WEST UNTIL COLD AIR ADVECTION WASHES
OUT THE MELTING LAYER.

THEREAFTER...THERE IS GOOD AGREEMENT AMONG 12 UTC ECMWF/GFS/GEM
GLOBAL AND 06 UTC GEFS THAT QUASI-ZONAL UPPER LEVEL FLOW WILL
TRANSITION TO A MORE AMPLIFIED PROGRESSIVE PATTERN. VERY LIGHT MODEL
QPF AND TIMING ISSUES MAKE CHANCES OF PRECIPITATION VERY SMALL WHEN
BLENDING...THOUGH THE PATTERN SUGGESTS THAT AT LEAST A COUPLE WAVES
WILL MOVE THROUGH THE REGION AND RESULT IN LIGHT SNOW. SUBSEQUENT
MODEL CYCLES SHOULD PROVIDE MORE CLARITY ON THIS ISSUE.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 552 PM CST WED NOV 26 2014

MVFR CIGS OVER WESTERN NORTH DAKOTA WILL LIFT EAST INTO CENTRAL
NORTH DAKOTA TONIGHT. LIGHT SNOW WILL THEN DEVELOP WEST THURSDAY
MORNING...THEN SPREAD EAST THROUGH THE AFTERNOON. SNOW IS EXPECTED
TO CHANGE TO A WINTRY MIX OVER KDIK THURSDAY AFTERNOON...BUT
REMAIN SNOW ELSEWHERE. SEE INDIVIDUAL TAFS FOR TIMING DETAILS.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
FREEZING RAIN ADVISORY FROM NOON CST /11 AM MST/ THURSDAY TO
MIDNIGHT CST /11 PM MST/ THURSDAY NIGHT FOR NDZ017>020-031>034-
042-045.

WINTER WEATHER ADVISORY FROM NOON THURSDAY TO 6 AM CST FRIDAY
FOR NDZ001>005-009>013-021.

FREEZING RAIN ADVISORY FROM 5 AM TO 11 AM MST THURSDAY FOR
NDZ040-041-043-044.

&&

$$

UPDATE...TM
SHORT TERM...WAA
LONG TERM...SCHECK
AVIATION...TM




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