000
FXUS63 KBIS 231803
AFDBIS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
103 PM CDT THU MAY 23 2013

.UPDATE...
ISSUED AT 103 PM CDT THU MAY 23 2013

NO SIGNIFICANT CHANGES REQUIRED WITH THIS FORECAST UPDATE OTHER
THAN TO BLEND TO THE 18 UTC OBSERVED TRENDS. THE MAIN QUESTION IS
WHETHER THE WIND ADVISORY FOR SOUTHWEST NORTH DAKOTA WILL NEED TO
BE EXTENDED PAST 03 UTC. THE LOW LEVEL WIND FIELD DOES STRENGTHEN
PAST 03 UTC...HOWEVER...LAPSE RATES DECREASE TO NEAR ISOTHERMAL
THROUGH 900 MB...WHICH PLACES UNCERTAINTY AS TO HOW MUCH
MOMENTUM CAN BE TRANSFERRED TO THE SURFACE. WILL CONTINUE TO
EVALUATE.

UPDATE ISSUED AT 955 AM CDT THU MAY 23 2013

NO SIGNIFICANT CHANGES REQUIRED WITH THIS FORECAST UPDATE OTHER
THAN TO BLEND TO THE 12 UTC OBSERVED TRENDS. THE WIND ADVISORY
FOR SOUTHWEST NORTH DAKOTA LOOKS ON TRACK WITH NO CHANGES PLANNED
BASED UPON THE 06 UTC NAM/GFS BUFR SOUNDINGS.

UPDATE ISSUED AT 645 AM CDT THU MAY 23 2013

THE CURRENT WIND ADVISORY LOOKS GOOD FOR SOUTHWESTERN NORTH DAKOTA
TODAY. NO UPDATES TO HEADLINES ARE REQUIRED. OTHERWISE...NOT TOO
MANY CHANGES WERE MADE TO THE ONGOING FORECAST. ONLY ADJUSTED THE
HOURLY SENSIBLE WEATHER GRIDS BASED ON CURRENT OBS/TRENDS. THE
UPDATED GRIDDED AND TEXT PRODUCTS HAVE BEEN SENT.

&&

.SHORT TERM...(TODAY AND TONIGHT)

ISSUED AT 345 AM CDT THU MAY 23 2013

MAIN FORECAST HIGHLIGHT IN THE SHORT TERM PERIOD WILL BE STRONG
WINDS DEVELOPING THIS MORNING AND LASTING INTO THIS EVENING ACROSS
SOUTHWESTERN NORTH DAKOTA.

CURRENTLY...NARROW RIDGE OF HIGH PRESSURE EXTENDS SOUTH TO NORTH
ACROSS THE GREAT PLAINS INTO SOUTH CENTRAL CANADA THIS
MORNING...WITH A STRONG CLOSED UPPER LOW QUASI-STATIONARY OVER
THE PACIFIC NORTHWEST AND A LONG WAVE TROUGH OVER THE EASTERN
CONUS. SCT-BKN UPPER LEVEL CIRRUS FROM EARLIER CONVECTION OVER
THE ROCKIES ADVECTING NORTH-NORTHEAST ACROSS CENTRAL/EASTERN
MONTANA INTO MY WESTERN COUNTIES. MODELS MAINTAIN UPPER LEVEL
CLOUDS PUSHING ACROSS NORTH DAKOTA THROUGHOUT THE DAY TODAY FROM
PRECIPITATION GENERATED FROM THE UPPER LOW OFF TO OUR WEST. CLOUDS
MAY BE THICK ENOUGH TO IMPACT DAYTIME HIGHS SOMEWHAT...MAINLY
SOUTHWEST WHERE THE BETTER PERFORMING MODELS HAVE SLIGHTLY COOLER
DAYTIME HIGHS COMPARED TO MY CENTRAL AND NORTHWEST COUNTIES.

OTHERWISE FOR TODAY...DEEPENING LOW PRESSURE ACROSS WYOMING AND
MONTANA TIGHTENS THE PRESSURE GRADIENT ACROSS THE DAKOTAS THIS
MORNING AND AFTERNOON...ESPECIALLY THE WESTERN DAKOTAS WHERE WIND
HEADLINES REMAIN IN EFFECT. THE STRONGEST WINDS ARE STILL EXPECTED
TO BE ACROSS THE SOUTHWEST WHERE GRADIENT FORCING IS
GREATEST...YIELDING SUSTAINED WINDS TO 35 MPH AND PEAK GUSTS
APPROACHING 50 MPH. OPTED TO LEAVE THE WIND ADVISORY AS IS...BUT
MAY NEED TO BE EXTENDED IN TIME...POSSIBLY EXPANDED EAST...AS THE
TIGHT GRADIENT DEVELOPS OVER CENTRAL NORTH DAKOTA TONIGHT AND
NEVER RELAXES UNTIL FRIDAY MORNING/AFTERNOON. IN ADDITION...MODELS
ARE DEVELOPING A STRONG 50-55KT LOW LEVEL JET TONIGHT...WHICH MAY
PROVIDE SOME MOMENTUM TRANSFER TO THE SURFACE. THE LIMITING FACTOR
WILL BE THE DEVELOPMENT OF THE NIGHTTIME INVERSION AROUND 02-04Z
THIS THURSDAY EVENING. THUS THERE REMAINS SOME UNCERTAINTY WHETHER
OR NOT THE WINDS WILL REMAIN STRONG THROUGH THE NIGHT AND HOW FAR
EAST THEY DEVELOP.

STRONG MID LEVEL IMPULSE WITHIN THE UPPER LOW ROTATES NORTHEAST
TOWARDS CENTRAL MONTANA LATE TONIGHT...BUT AT THIS TIME IT APPEARS
ALL ASSOCIATED PRECIPITATION WILL REMAIN OFF TO OUR WEST THROUGH
12Z FRIDAY MORNING SO KEPT THURSDAY NIGHT DRY.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 345 AM CDT THU MAY 23 2013

FRIDAY KICKS OFF A PROLONGED PERIOD OF UNSETTLED WEATHER OVER
WESTERN AND CENTRAL NORTH DAKOTA. THE MEDIUM RANGE MODELS DIFFER
WITH RESPECT TO THE DETAILS OF THE TIMING OF PRECIPITATION CHANCES.
HOWEVER...THE MODELS ARE CONSISTENT WITH RESPECT TO THE OVERALL
SYNOPTIC PATTERN OVER THE NORTHERN PLAINS THROUGH THE EXTENDED. AS A
RESULT...CONTINUED TO FOLLOW A BLEND OF SOLUTIONS FOR THE FORECAST.

AN UPPER LOW OVER THE PACIFIC NORTHWEST IS PROGGED TO EJECT ITS
FIRST IMPULSE ACROSS WESTERN AND CENTRAL NORTH DAKOTA FRIDAY. THE
MEDIUM RANGE MODELS ARE A LITTLE FARTHER EAST WITH PRECIP
DEVELOPMENT THAN THE PREVIOUS MODEL RUNS. AS A RESULT...SHIFTED
FRIDAY AFTERNOON POPS A LITTLE FARTHER EAST.

A LULL IN ACTIVITY IS FORECAST LATE FRIDAY NIGHT/EARLY SATURDAY
BEFORE A SECONDARY SHORTWAVE IS PROGGED TO LIFT NORTH ACROSS WESTERN
NORTH DAKOTA SATURDAY AFTERNOON AND NIGHT. THE UPPER DISTURBANCE
COMBINED WITH A LITTLE BETTER DEEP LAYER SHEAR AND INSTABILITY IS
FORECAST DURING THIS PERIOD. THIS COULD GENERATE THE POSSIBILITY OF
SEVERE THUNDERSTORMS DEVELOPING WEST SATURDAY AFTERNOON/NIGHT.
HOWEVER...CONFIDENCE IN STORMS BECOMING SEVERE IS STILL LOW AT THIS
TIME. SPC CONCURS AND HAS THIS AREA UNDER "SEE TEXT" FOR THE DAY 3
CONVECTIVE OUTLOOK. AS A RESULT...WILL KEEP THE SEVERE MENTION OUT
OF THE ZONES AND HIGHLIGHT THE POSSIBILITY IN THE HWO FOR NOW.

AN UNSETTLED WEATHER PATTERN WILL CONTINUE NEXT WEEK. PERSISTENT
SOUTHWESTERLY FLOW ALOFT COMBINED WITH GULF OF MEXICO MOISTURE TAP
WILL LEAD TO CHANCES FOR THUNDERSTORMS EACH DAY THROUGH THE FIRST
HALF OF NEXT WEEK. THE PERSISTENT RETURN FLOW SHOULD ALSO ALLOW FOR
A GRADUAL WARMING TREND TO CONTINUE THROUGH THE END OF THE PERIOD.
BY WEDNESDAY...HIGHS SHOULD GENERALLY BE IN THE MID 70S.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY)
ISSUED AT 103 PM CDT THU MAY 23 2013

VFR CONDITIONS EXPECTED FOR THE 18Z TAF CYCLE. THE MAIN HAZARD TO
AVIATION WILL BE MODERATE TO STRONG SURFACE WINDS OF 25 TO 35 KTS
FROM THE SOUTHEAST THIS AFTERNOON OVER WESTERN TERMINALS...INCLUDING
KISN- KDIK.


&&

.BIS WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 10 PM CDT /9 PM MDT/ THIS EVENING FOR NDZ017-
018-031>033-040-041-043-044.

&&

$$

UPDATE...AYD
SHORT TERM...NH
LONG TERM...TM
AVIATION...AYD