Area Forecast Discussion
Issued by NWS Bismarck, ND

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS63 KBIS 251356
AFDBIS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
856 AM CDT MON MAY 25 2015

.UPDATE...
ISSUED AT 851 AM CDT MON MAY 25 2015

MAIN CHANGE WITH THIS FORECAST UPDATE WAS TO INTRODUCE POPS
THIS AFTERNOON AND EARLY EVENING ACROSS THE NORTHWEST AND NORTH
CENTRAL. THE 11-12 UTC HRRR AND RAP SUGGEST WEAK...SURFACE BASED
CONVECTION WITH DIURNAL HEATING. THIS IS ALSO SUPPORTED BY THE 06
UTC NAM AND 09 UTC SREF. SEVERE WEATHER IS NOT EXPECTED.

UPDATE ISSUED AT 649 AM CDT MON MAY 25 2015

THE PREVIOUS FORECAST IS ON TRACK. NOW THAT THE PRECIPITATION
SHIELD HAS FILLED IN...THERE IS BETTER JUSTIFICATION TO BUMP UP
PRECIPITATION CHANCES FROM THE JAMES VALLEY TO THE EASTERN
MISSOURI VALLEY THIS MORNING. OTHERWISE...MADE ONLY AESTHETIC
CHANGES TO THE FORECAST.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 420 AM CDT MON MAY 25 2015

THE MAIN FOCUS FOR THE SHORT TERM IS RAIN.

EARLY THIS MORNING WIDESPREAD RAIN SHOWERS WERE BREAKING OUT
ACROSS SOUTHERN NORTH DAKOTA AHEAD OF A SURFACE LOW AND VORT MAX
IN CENTRAL SOUTH DAKOTA. LIGHT WIDESPREAD RAIN IS EXPECTED TO
CONTINUE...MAINLY ACROSS THE SOUTHERN HALF OF NORTH
DAKOTA...THROUGH THIS AFTERNOON.

SEVERAL UPPER LEVEL WAVES WERE VISIBLE IN WATER VAPOR IMAGERY
OVER THE NORTHERN PLAINS. ONE WAS CENTERED ACROSS NORTH CENTRAL
SOUTH DAKOTA. THE MODELS HAVE THIS VORT MAX PHASING WITH THE OTHER
NEARBY IMPULSES THIS AFTERNOON AND QUICKLY EXITING THE REGION. THE
WRF/RAP SHOW RAIN SCATTERING OUT AND WINDING DOWN BY LATE THIS
AFTERNOON. WRF/RAP ALSO INDICATE SOME INSTABILITY MIGHT DEVELOP
ACROSS SOUTHWESTERN NORTH DAKOTA THIS AFTERNOON. THEREFORE...KEPT
A MENTION OF ISOLATED THUNDERSTORMS ACROSS THE SOUTHWEST...BUT
REMOVED THUNDERSTORM CHANCES EVERYWHERE ELSE. ISOLATED SHOWERS ARE
POSSIBLE IN THE WAKE OF THE DEPARTING LOW. WITH THE SURFACE LOW
AND BEST FORCING OFF TO THE SOUTHEAST...SOUTH CENTRAL AND
SOUTHEAST NORTH DAKOTA WILL LIKELY SEE THE BULK OF THE RAIN.
AMOUNTS SHOULD GENERALLY RANGE FROM 0.5 TO AS MUCH AS 1.0 INCHES.

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 420 AM CDT MON MAY 25 2015

THE FORECAST FOCUS THIS MORNING IS ON PRECIPITATION.

EASTERN PACIFIC REX BLOCKING AND RESULTANT DOWNSTREAM SPLIT FLOW
ALOFT WILL RESULT IN SEVERAL DAYS WITH PRECIPITATION CHANCES.
BECAUSE OF THE FLOW REGIME COMPLEXITY...THOUGH... FORECASTS HAVE
HIGHER THAN NORMAL UNCERTAINTY.

MUCH OF THE UNCERTAINTY STEMS FROM NORTH DAKOTA FALLING IN THE
ZONE BETWEEN NORTHERN AND SOUTHERN BRANCHES OF THE JET STREAM.
WHEN MID LEVEL SHORTWAVES WITHIN EACH BRANCH BECOME PHASED...THE
PRECIPITATION CHANCES ARE HIGHEST. SUCH IS THE CASE ON
WEDNESDAY...ACCORDING TO THE LATEST ECMWF/GFS/NAM/GEFS/GEM GLOBAL.
03 UTC SREF PROBABILITY FOR CAPE GREATER THAN 500 J/KG IS OVER 50
PERCENT WEDNESDAY AFTERNOON/EVENING ACROSS MUCH OF THE
DAKOTAS...SO THAT IS ALSO THE MOST LIKELY TIME FOR THUNDERSTORMS
THROUGH THE PERIOD. OTHERWISE...THERE ARE SEVERAL SHORTWAVES THAT
JUSTIFY SMALL CHANCES FOR PRECIPITATION THROUGH THE PERIOD.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 851 AM CDT MON MAY 25 2015

WIDESPREAD MVFR CONDITIONS IN RAIN WILL CONTINUE AT KBIS AND KJMS
INTO THE EARLY AFTERNOON...WITH RAIN BECOMING MORE SCATTERED
THEREAFTER. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE
EXPECTED TO DEVELOP ELSEWHERE ACROSS WESTERN AND CENTRAL NORTH
DAKOTA THIS AFTERNOON AND EARLY EVENING. WILL INTRODUCE VCSH FOR
NOW AT KDIK/KISN/KMOT.

&&

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

$$

UPDATE...AYD
SHORT TERM...AJ
LONG TERM...SCHECK
AVIATION...AYD


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.