736 
FXUS63 KBIS 091801
AFDBIS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
101 PM CDT THU MAY 9 2013

.UPDATE...
ISSUED AT 1250 PM CDT THU MAY 9 2013

THIS AFTERNOON ISOLATED RAIN SHOWERS CONTINUE ACROSS PORTIONS OF
FAR SOUTHWEST NORTH DAKOTA. CONTINUED STRONG COLD AIR ADVECTION
HAS KEPT TEMPERATURES SLIGHTLY COOLER THAN EXPECTED ACROSS THE
NORTH. CLOUD COVER IN THE SOUTHWEST HAS ALSO KEPT TEMPERATURES
FROM RISING QUICKLY. THEREFORE...FOR THIS UPDATE LOWERED
TEMPERATURES SLIGHTLY TO FOLLOW LATEST TRENDS. OTHERWISE THE
FORECAST IS ON TRACK WITH ALL HOURLY WEATHER GRIDS UPDATED WITH
OBSERVATIONS AND LATEST TRENDS. 

UPDATE ISSUED AT 1000 AM CDT THU MAY 9 2013

A WEAK SHORTWAVE TOUGH VISIBLE IN WATER VAPOR CONTINUES TO
PROPAGATE SOUTHEAST THROUGH EASTERN MONTANA AND WESTERN NORTH
DAKOTA. LATEST BOWMAN RADAR IMAGE SHOWS ISOLATED SHOWERS ACROSS
FAR SOUTHWEST NORTH DAKOTA AHEAD OF THE MENTIONED SHORTWAVE. THE 13 UTC
HRRR AND 00 UTC NCEP WRF SHOW ISOLATED TO SCATTERED RAIN SHOWERS
CONTINUING THROUGH THE AFTERNOON HOURS. 

THEREFORE...LEFT CHANCES FOR RAIN SHOWERS AND AN ISOLATED
THUNDERSTORM THROUGH AFTERNOON AND EARLY EVENING HOURS. ALSO
EXPANDED CHANCES EAST SLIGHTLY BASED ON CURRENT TRENDS. ALSO
LOWERED TEMPERATURES AND DEW POINTS SLIGHTLY FOR THE REST OF TODAY
AS COLD AIR ADVECTION CONTINUES WITH NORTHEASTERLY WINDS AND
SURFACE HIGH PRESSURE TO THE EAST. UPDATED THE REST OF THE
FORECAST GRIDS TO REFLECT CURRENT OBS/TRENDS. ALL UPDATED PRODUCTS
HAVE BEEN SENT.

UPDATE ISSUED AT 655 AM CDT THU MAY 9 2013

LATEST SURFACE ANALYSIS SHOWS A SURFACE HIGH PRESSURE RIDGE
EXTENDING FROM MANITOBA SOUTH INTO CENTRAL NORTH DAKOTA. CLEAR
SKIES OVER MUCH OF CENTRAL NORTH DAKOTA IS RESULTING IN SUB
FREEZING TEMPERATURES AGAIN THIS MORNING. LATEST WV IMAGERY SHOWS
AN IMPULSE OVER NORTH CENTRAL MONTANA TRACKING SOUTHEAST. THIS IS
PRODUCING AN AREA OF MID LEVEL CLOUDINESS OVER EASTERN MONTANA AND
SOUTHWEST AND FAR SOUTH CENTRAL NORTH DAKOTA. VERY LIGHT
REFLECTIVITY'S INDICATED ON AREA RADARS BUT EXPECT LITTLE IF ANY
MOISTURE IS REACHING THE GROUND. IF ANYTHING MAYBE A FEW SPRINKLES
UNDER THE HIGHER REFLECTIVITY OVER THE FAR SOUTHWEST. CURRENT
SLIGHT CHANCE MORNING POPS IN THE FAR SOUTHWEST SHOULD COVER THIS. 

MADE A FEW ADJUSTMENTS CLOUD COVER TO MATCH UP WITH LATEST
SATELLITE IMAGERY...AND POPULATED LATEST SENSIBLE WEATHER GRIDS.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 310 AM CDT THU MAY 9 2013

LATEST WATER VAPOR IMAGERY SHOWS A SHORTWAVE CONTINUING TO WORK
ITS WAY FROM SOUTHEAST ALBERTA TO NEAR HAVRE MONTANA EARLY THIS
MORNING. WEAK UPWARD VERTICAL MOTION/UPPER LEVEL DIVERGENCE PER
REGIONAL RADAR SHOWS MAX REFLECTIVITY'S OF AROUND 25DBZ...STRETCHING
FROM WESTERN MCKENZIE COUNTY IN NORTH DAKOTA INTO CUSTER COUNTY MONTANA.
WITH SURFACE OBSERVATIONS INDICATING CEILINGS OF 11KFT...SUSPECT THIS
IS VIRGA AT BEST AND WILL NOT MENTION ANY MEASURABLE PRECIPITATION/POPS
PRIOR TO 12Z THURSDAY. THE BOWMAN RADAR INDICATES MUCH THE SAME
SCENARIO. ANOTHER SHORTWAVE IS FORECAST TO PUSH INTO WESTERN NORTH
DAKOTA THIS AFTERNOON...WITH MARGINAL THUNDERSTORM PARAMETERS JUST
SCRAPING THE FAR SOUTHWEST. OVERALL...ONLY A SLIGHT CHC/ISOLATED
SHOWER/THUNDERSTORM IS FORECAST IN THE FAR SOUTHWEST TODAY. ELSEWHERE
EXPECT DRY CONDITIONS UNDER PARTLY TO MOSTLY SUNNY SKIES. AFTERNOON
HIGH TEMPERATURES WILL GENERALLY RANGE BETWEEN 60F AND 65. DRY
CONDITIONS WILL EXTEND INTO THURSDAY NIGHT WITH LOWS IN THE MID
30S CENTRAL TO AROUND 40 WEST.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 310 AM CDT THU MAY 9 2013

A COLD FRONT WILL MOVE THROUGH THE AREA ON FRIDAY BRINGING MUCH 
COOLER TEMPERATURES TO THE REGION TO BEGIN THE WEEKEND. 
DETERMINISTIC MODELS ARE SIMILAR WITH THE POSITION OF THE COLD FRONT 
BY 00 UTC SATURDAY...WITH THE ECMWF MOST CONSISTENT OVER THE PAST 
FEW RUNS...AND MORE PROGRESSIVE GFS/GEM ARE COMING CLOSER IN LINE. 
LITTLE CHANGES TO PREVIOUS POP FORECAST ON FRIDAY...ALTHOUGH DID 
BUMP UP POPS OVER THE SOUTHEAST CWA FRIDAY AFTERNOON. CONVECTIVE 
POTENTIAL LOOKS LESS FAVORABLE THAN PREVIOUS RUNS...BUT STILL 
MARGINAL CAPE AVAILABLE FOR A FEW HOURS FRIDAY MORNING NORTH AND 
MORE SO FRIDAY AFTERNOON SOUTH...SO WILL KEEP A MENTION OF THUNDER 
IN THE FORECAST. 

STRONG NORTHWEST WINDS WILL QUICKLY BRING COOL AND DRY HIGH PRESSURE 
BEHIND THE COLD FRONT. WITH THE STRONG WINDS...AND LOWERING 
HUMIDITIES BEHIND THE COLD FRONT...FIRE DANGER WILL BE A CONCERN. 
COOLER POST-FRONTAL TEMPERATURES AND ANY PRECIPITATION THAT FALLS 
WILL BE LIMITING FACTORS. WILL NOT ISSUE ANY FIRE WEATHER HIGHLIGHTS 
AT THIS TIME...BUT WILL PASS ALONG TO LATER SHIFTS.

COOL HIGH PRESSURE WILL TRAVERSE THE AREA FRIDAY NIGHT THROUGH 
SATURDAY NIGHT BRINGING DRY CONDITIONS AND BELOW NORMAL TEMPERATURES 
IN THE 50S ON SATURDAY...AND COOL OVERNIGHT LOWS IN THE 30S FRIDAY 
NIGHT AND SATURDAY NIGHT.

AN UPPER LEVEL RIDGE WILL MOVE INTO EASTERN MONTANA ON SUNDAY AND 
ACROSS NORTH DAKOTA ON MONDAY THIS WILL BRING PROGRESSIVELY WARMER 
TEMPERATURES SUNDAY AND MONDAY...WITH HIGHS IN THE 80S ACROSS MOST 
OF THE REGION ON MONDAY. 

UPPER LEVEL FLOW WILL FLATTEN AND A QUASI-ZONAL FLOW WILL TAKE SHAPE 
THROUGH THE REMAINDER OF THE FORECAST PERIOD. THIS WILL BRING 
TEMPERATURES BACK DOWN TO AROUND NORMAL TUESDAY AND WEDNESDAY. 
PROGRESSIVE FLOW WILL ALSO BRING PERIODIC CHANCES OF SHOWERS AND 
THUNDERSTORMS...MOST NOTABLY MONDAY NIGHT...WITH ISOLATED SHOWERS 
AND THUNDERSTORMS TUESDAY THROUGH WEDNESDAY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY MORNING) ISSUED AT
1200 PM CDT THU MAY 9 2013

BIGGEST IMPACTS FOR AVIATION WILL ARRIVE TOMORROW MORNING IN THE
FORM OF GUSTY WINDS AND A CHANCE FOR SHOWERS AND ISOLATED
THUNDERSTORMS. A STRONG COLD FRONT WILL ARRIVE AT KISN/KMOT
AROUND 14Z AND KDIK/KBIS/KJMS AROUND 16Z. BEHIND THE FRONT WINDS
WILL SHIFT OUT OF THE NORTH FROM 20 TO 30 KNOTS. THERE IS A SLIGHT
CHANCE OF SHOWERS AND ISOLATED THUNDERSTORMS ALONG THE COLD FRONT AT
ALL TERMINALS. HOWEVER THERE IS UNCERTAINTY AS TO EXACT TIMING AND
LOCATION OF ANY PRECIPITATION THAT DOES DEVELOP. THEREFORE...LEFT
ONLY A MENTION OF VCSH IN THE TAFS. VFR CONDITIONS WILL PERSIST AT ALL
TERMINALS THROUGH THE TAF PERIOD.


&&

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

$$

UPDATE...AJ
SHORT TERM...KS
LONG TERM...TWH
AVIATION...AJ