Snow Advisory 7, NWS Bismarck, ND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
408 AM CDT SAT MAR 29 2008

.SHORT TERM...TODAY THROUGH MONDAY NIGHT...
FORECAST CONCERNS/HIGHLIGHTS IN THE SHORT TERM WILL FOCUS ON TWO
STORM SYSTEMS...THE FIRST MOVING THROUGH THE REGION TODAY AND THE
SECOND IMPACTING THE STATE SUNDAY NIGHT INTO MONDAY. USED A GENERAL
MODEL BLEND BUT LEANED MORE TOWARDS THE GFS/ECMWF SOLUTIONS.

CURRENTLY...A STRONG UPPER LEVEL SHORT WAVE HAS MOVED ONSHORE OVER
THE PACIFIC NORTHWEST AND IS POSITIONED IN FAR WESTERN
MONTANA...WITH DEVELOPING SURFACE LOW PRESSURE IN THE SAME GENERAL
VICINITY. INCREASING MID/UPPER LEVEL CLOUDS AHEAD OF THIS SYSTEM
ACROSS THE CWA ATTM ALONG WITH AREAS OF LOW CIGS AND FOG ACROSS THE
FAR NORTH. SFC WINDS ARE BECOMING MORE SOUTH/SOUTHEAST AS THE SFC
LOW OFF TO OUR WEST INTENSIFIES. WILL LEAVE FOG OUT OF THE
FORECAST THIS MORNING ACROSS THE NORTH WITH FOG LIFTING AS MID
LEVEL CLOUDS ADVECT OVERHEAD.

MODELS IN DECENT AGREEMENT WITH THE TRACK OF THE UPPER LEVEL SHORT
WAVE AND SURFACE LOW AS IT MOVES INTO AND THROUGH THE REGION TODAY
AND TONIGHT. AS FAR AS PRECIPITATION GOES...NOT MUCH TO SPEAK OF
THIS MORNING BESIDES ACROSS THE NORTHWEST AND NORTH CENTRAL WHERE
ISENTROPIC UPGLIDE AND FRONTOGENESIS IS MAXIMIZED. COULD SEE UP TO
AROUND 2 MAYBE 3 INCHES OF SNOW HERE BY EARLY AFTERNOON. THE GFS
TRIES TO GENERATE SOME LIGHT WAA PRECIP OVER MY EASTERN COUNTIES BUT
THINK THIS IS OVERDONE SO SCALED BACK THERE. REMAINDER OF THE CWA
(SOUTHWEST AND SOUTH CENTRAL) REMAINS IN THE DRY SLOT THIS MORNING.
FOR THE AFTERNOON...THINGS BECOME A BIT MORE INTERESTING AS A STRONG
COLD FRONT APPROACHES MY CENTRAL COUNTIES. GOOD SURFACE CONVERGENCE
ALONG THIS FRONTAL BOUNDARY WILL TRIGGER AFTERNOON SHOWERS ACROSS
MUCH OF CENTRAL NORTH DAKOTA SO HAVE UPPED POPS HERE. MAY SEE SOME
THUNDER AS WELL SO INSERTED ISOLD T FAR SOUTH CENTRAL THIS
AFTERNOON. SNOW LOOKS TO CONTINUE FAR NORTH CENTRAL AT LEAST
THROUGH THE EARLY AFTERNOON HOURS. GIVEN THE INTENSITY OF THE
UPPER LEVEL WAVE AND POSSIBLE CONVECTIVE SNOWFALL...COULD SEE SOME
ACCUMULATIONS IN EXCESS OF THREE INCHES. THUS WILL ISSUE A SNOW
ADVISORY ACROSS MY NORTHERN TIER COUNTIES AND KEEP IT THROUGH 06Z
TO ACCOUNT FOR WRAP AROUND SNOW THIS EVENING.

LIGHT TO MODERATE SHOWER ACTIVITY CONTINUES OVER MY EAST CENTRAL AND
SOUTHEASTERN ZONES THIS EVENING ALONG THE COLD FROPA...AS WILL AS
ADDITIONAL LIGHT SNOWFALL OVER THE NORTH WITH WRAP AROUND SNOW.
AFTER 06Z SNOW STARTS TO WIND DOWN AS THE SYSTEM LIFTS NORTHEAST.

ANOTHER CONCERN TODAY ARE THE WINDS ASSOCIATED WITH THIS SURFACE
LOW. STRONG SOUTHERLY FLOW AHEAD OF THE LOW WILL CREATE ADVISORY
LEVEL WINDS OVER MY SOUTH CENTRAL AND EASTERN COUNTIES THIS MORNING
INTO THE EARLY EVENING HOURS TONIGHT. DESPITE THE STRONG SURFACE
CONVERGENCE WITH THIS SYSTEMS COLD FRONT MOVING THROUGH THE WEST
THIS AFTERNOON...WINDS REMAIN BELOW ADV LEVELS HERE AS NOT A VERY
SUPPORTIVE PRESSURE GRADIENT OR LINKAGE. A SECONDARY COLD FRONT
APPROACHES LATER TONIGHT BUT BY THIS TIME STRONGER WINDS ALOFT
WILL HAVE A HARD TIME MIXING DOWN TO THE SFC. WINDS WILL STILL BE
ON THE BREEZY SIDE HOWEVER AFTER MIDNIGHT AND INTO SUNDAY MORNING.
WINDS TODAY WILL ALSO ELEVATE FIRE WEATHER CONCERNS (SEE BELOW).

SUNDAY REMAINS RELATIVELY QUIET WITH HIGH PRESSURE DOMINATING THE
WEATHER. THIS IS SHORT LIVED THOUGH AS ANOTHER STORM SYSTEM
APPROACHES AND MOVES INTO THE CENTRAL PLAINS SUNDAY NIGHT INTO
MONDAY. MODELS HAVE CONTINUED TO TREND NORTH WITH THE PRECIP SHIELD
SO HAVE INCREASED POPS ACCORDINGLY MAINLY ACROSS THE SOUTHERN TWO
THIRDS OF THE FORECAST AREA.

.LONG TERM...TUESDAY THROUGH SATURDAY...
UPPER LEVEL RIDGING WILL KEEP THE WEATHER DRY AND SEASONABLE ON
TUESDAY AND WEDNESDAY. THE GFS AND ECMWF ARE IN AGREEMENT ON THIS
PROJECTION. FURTHER DOWN THE ROAD THE MODELS INDICATE FAIRLY
QUIESCENT WEATHER WITH NO MAJOR SPRING STORMS FOR THE NORTHERN
PLAINS.

&&

.AVIATION...
DEEPENING LOW PRESSURE WILL MOVE EAST NORTHEAST TO NEAR WINNEPEG BY
LATE TONIGHT. THIS IS A COMPLEX SITUATION WHICH WILL PROMOTE A VERY
WIDE RANGE OF WEATHER OVER THE STATE TODAY AND TONIGHT. WITH A
LIFTING WARM FRONT WE WILL HAVE LOW CEILINGS AND AREAS OF FOG TO ITS
NORTH OVER THE NORTHERN PART OF THE STATE THIS MORNING...THEN
SIGNIFICANT SNOWFALL LATER WHEN THE LOW PRESSURE SYSTEM STRENGTHENS.
THE BEST WEATHER WILL BE IN THE SOUTH...IN THE WARMER AND DRIER PART
OF THE LOW.

&&

.FIRE WEATHER...
ELEVATED FIRE WEATHER CONCERNS TODAY ACROSS THE SOUTHWEST AND
SOUTH CENTRAL WHERE THE RANGELAND FIRE DANGER INDEX WILL BE IN THE
HIGH TO VERY HIGH CATEGORY. PRIMARY CONCERN IS THE SOUTH CENTRAL
WHERE GUSTY SOUTHERLY WINDS ARE EXPECTED (HENCE A WIND ADV) ALONG
WITH AFTERNOON HUMIDITIES 25 TO 30 PERCENT. IN ADDITION...WILL
SEE A WIND SHIFT TO MORE WESTERLY EARLY THIS EVENING AS A SURFACE
COLD FRONT MOVES ACROSS THE CENTRAL DAKOTAS. ALTHOUGH WEATHER
CRITERIA IS MARGINAL...GIVEN THE VERY DRY GRASSLANDS THINK IT IS
PRUDENT TO GO WITH A RED FLAG WARNING OVER MY SOUTH CENTRAL
COUNTIES. DAYSHIFT CAN REEVALUATE AND CANCEL IF NEEDED.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 10 AM THIS MORNING TO 10 PM CDT THIS EVENING
FOR NDZ022-023-025-035>037-046>048-050-051.

RED FLAG WARNING FROM 10 AM CDT /9 AM MDT/ THIS MORNING TO 10 PM
CDT /9 PM MDT/ THIS EVENING FOR NDZ034-035-042-045-046.

WIND ADVISORY FROM 10 AM CDT /9 AM MDT/ THIS MORNING TO 7 PM CDT
/6 PM MDT/ THIS EVENING FOR NDZ019>021-034-042-045.

SNOW ADVISORY UNTIL 1 AM CDT SUNDAY FOR NDZ001>005.

&&

NH/RSL