Area Forecast Discussion
Issued by NWS Bismarck, ND

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000
FXUS63 KBIS 142131
AFDBIS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
331 PM CST SUN FEB 14 2016

.SHORT TERM...(THIS EVENING THROUGH MONDAY)

ISSUED AT 330 PM CST SUN FEB 14 2016

MILD WEATHER WILL CONTINUE THROUGH MONDAY...WITH SOME PATCHY FOG
POSSIBLE TONIGHT OVER CENTRAL ND AND AN INCREASING CHANCE OF LIGHT
RAIN OR SNOW OVER WESTERN AND CENTRAL ND MONDAY AFTERNOON.

FIRST OF ALL...WE HAVE REMOVED ANY MENTION OF FREEZING DRIZZLE IN
THE FORECAST FOR THE REMAINDER OF THE AFTERNOON GIVEN THE LACK OF
OBSERVATIONAL EVIDENCE OF IT OVER EAST CENTRAL ND THROUGH 21 UTC.
FORECAST SOUNDINGS IN PLACES LIKE JAMESTOWN SHOW THE STRATUS DECK
/LOW CLOUDS/ BEING WARMER THAN -12 C...WHICH SUPPORTS SUPERCOOLED
LIQUID DROPS AND NOT ICE CRYSTALS...BUT OMEGA IN THAT LAYER IS ON
ITS WAY DOWNWARD AND SO THE PROBABILITY OF FREEZING DRIZZLE WILL
ONLY LOWER THROUGH THE REST OF THE DAY.

TONIGHT...WE ADDED PATCHY FOG TO THE FORECAST OVER CENTRAL ND OUT
OF RESPECT TO SNOWMELT TODAY...INITIALLY-LIGHT WINDS WITHIN 1000
FT OF THE GROUND...AND SIMULATION OF ITS DEVELOPMENT IN THE 15-19
UTC RUNS OF THE OPERATIONAL AND EXPERIMENTAL HRRR AND THE 12 UTC
NAM-NEST. HOWEVER...FORECAST SOUNDINGS SUGGEST THE LOW LEVELS MAY
BECOME A BIT TOO TURBULENT FOR FOG IN MOST AREAS AFTER 09 UTC PER
INCREASING WESTERLY WINDS JUST ABOVE THE GROUND...WHICH PRODUCES
MODIFIED RICHARDSON NUMBERS GREATER THAN 0.00. OTHERWISE...WE ARE
EXPECTING A RELATIVELY MILD NIGHT WITH LOWS IN THE 20S F...AND IT
SHOULD BE DRY AFTER ANY LATE-AFTERNOON SHOWERS IN SOUTHWESTERN ND
DISSIPATE AS A WEAK SHORTWAVE TROUGH CONTINUES INTO SD.

ON MONDAY...THE 12 UTC GFS...ECMWF...AND NAM ALL SHOW A SHORTWAVE
TROUGH MOVING INTO WESTERN ND BY AFTERNOON. THAT WAVE CAN BE SEEN
CRASHING ONTO THE CENTRAL BRITISH COLUMBIA COASTLINE ON AFTERNOON
MOISTURE CHANNEL IMAGERY...AND GIVEN ITS APPARENT CIRCULATION AND
POST-TROUGH DARKENING ON THOSE SATELLITE IMAGES...MODEL GUIDANCE
APPEARS VERY REASONABLE IN SHOWING A MODERATE TO POSSIBLY STRONG
SURGE OF QG-FORCING CROSSING THE AREA BEGINNING MONDAY AFTERNOON.
WE ARE THUS ADVERTISING POPS OF 40+ PERCENT OVER MOST OF WESTERN
AND CENTRAL ND MONDAY AFTERNOON. PRECIPITATION TYPE WILL LIKELY
BE DRIVEN MAINLY BY BOUNDARY LAYER TEMPERATURES AS THE WARM LAYER
ALOFT WILL INITIALLY BE SUB-SATURATED IN SOUTHWEST ND /PROMOTING
WET BULB COOLING/...AND TOO COLD FOR MELTING ALOFT ELSEWHERE WITH
850-MB TEMPERATURES BELOW 1 C. WE THUS HAVE A MIX OF RAIN AND SNOW
IN THE FORECAST ACROSS THE AREA...WITH QPF FROM 18 TO 00 UTC OF
0.10 INCHES OR LESS PER THE 12 UTC MODEL SUITE.


.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)

ISSUED AT 330 PM CST SUN FEB 14 2016

ACTIVE FLOW REMAINS OVER THE REGION FOR THE EARLY PORTION OF THE
WEEK...THEN WE FINALLY TRANSITION TO A MORE PROGRESSIVE FLOW
PATTERN FOR THE REMAINDER OF THE LONG TERM PERIOD.

MODELS TRENDING STRONGER WITH A S/WV TROUGH/CLIPPER SYSTEM MOVING
ACROSS THE NORTHERN PLAINS MONDAY AND MONDAY NIGHT. PRECIPITATION
TYPE BY MONDAY EVENING SHOULD BE ALL SNOW WITH MODELS IN AGREEMENT
WITH CAA LOWERING TEMPERATURES ALOFT TO BELOW FREEZING THROUGH THE
SATURATION LAYER. MAY SEE SOME LIGHT ACCUMULATIONS WITH THIS WAVE
GIVEN THE UPTICK IN QPF AND LIFT. CURRENT THINKING IS THAT THIS
WILL REMAIN SUB-ADVISORY TYPE SNOWFALL SO DID NOT MENTION IN THE
HWO WITH THIS FORECAST ISSUANCE.

THIS CLIPPER IS QUICKLY FOLLOWED BY ANOTHER WEAKER WAVE TUESDAY
THROUGH EARLY WEDNESDAY. THERMAL PROFILE SUGGEST ALL SNOW WITH
THIS S/WV.

BROAD UPPER LEVEL RIDGING WILL DRY THINGS OUT TOWARDS THURSDAY
ALONG WITH MILD/WELL ABOVE NORMAL TEMPERATURES IN THE 30S
EAST...40S NORTHWEST AND CENTRAL...AND MID/UPPER 50S OVER THE
SOUTHWEST. A GOOD SOUTHERLY RETURN FLOW WILL INCREASE MIXING AND
MAY LEAD TO EVEN WARMER DAYTIME HIGHS FOR THURSDAY THAN WHAT IS
CURRENTLY FORECAST. FOR NOW LEANED MORE CONSERVATIVE.

UPPER LEVEL S/WV TROUGH FOLLOWS THE RIDGE THURSDAY NIGHT/FRIDAY.
MODEL SPREAD STILL HIGH RIGHT NOW IN REGARDS TO THIS WAVE. MAY SEE
SOME IMPACTFUL WEATHER THOUGH ASSOCIATED WITH THIS TOWARDS THE
END OF THE WEEK...RIGHT NOW VERY UNCERTAIN BUT WILL BE WORTH
KEEPING AN EYE ON.


&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)

ISSUED AT 330 PM CST SUN FEB 14 2016

LINGERING MVFR CEILINGS FROM CENTRAL ND INTO THE JAMES RIVER VALLEY
COULD BRIEFLY LIFT INTO THE VFR RANGE IN THE LATE AFTERNOON AND
EVENING...BUT THEN A BRIEF WINDOW OF SOME FOG IS POSSIBLE TONIGHT
AND INTO THE EARLY MORNING HOURS ON MONDAY...FOLLOWED BY SOME LOW
STRATUS. ELSEWHERE...KISN AND KDIK SHOULD REMAIN IN VFR CONDITIONS
THROUGHOUT THE PERIOD. WINDS WILL GENERALLY REMAIN LIGHT OUT OF
THE WEST AND NORTHWEST.


&&

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

&&

$$

SHORT TERM...CJS
LONG TERM...NH
AVIATION...ZH/CJS


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