000
FXUS63 KBIS 231821
AFDBIS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
121 PM CDT WED JUL 23 2014

.UPDATE...
ISSUED AT 120 PM CDT WED JUL 23 2014

AREA OF SHOWERS HAS DIMINISHED AND MOVED EAST OF THE FORECAST
AREA. LATEST NAM/HRRR/GEM MODELS DO NOT INDICATE CONVECTION IN THE
SOUTHWEST THIS AFTERNOON...SO TOOK OUT MENTION OF SLIGHT CHANCES
OF THUNDER THERE. STILL LOOKING LIKE CHANCES OF LATE EVENING
THUNDERSTORMS IN THE FAR WEST...SPREADING INTO CENTRAL NORTH
DAKOTA AFTER MIDNIGHT. SEVERE CHANCES REACHING THE CENTRAL LOOKING
LESS LIKELY NOW. WILL CONCENTRATE ON CONVECTION TONIGHT AND
THURSDAY IN THE LATER AFTERNOON UPDATE.

UPDATE ISSUED AT 1008 AM CDT WED JUL 23 2014

AREA OF SHOWERS CONTINUED OVER PARTS OF NORTH CENTRAL NORTH
DAKOTA...MAINLY EAST OF MINOT AND BETWEEN THE HARVEY AND BOTTINEAU
AREA. MODELS INDICATE THIS AREA OF SHOWERS MOVING EAST AND
DISSIPATING THROUGHOUT THE DAY IN EASTERN NORTH DAKOTA. THUS ADDED
CHANCES OF SHOWERS WITH A SLIGHT CHANCE OF THUNDERSTORMS THERE FOR
THE REST OF THE MORNING.

ONLY OTHER CHANGE WAS TO INCREASE DEWPOINTS AS LOW LEVEL MOISTURE
SHOULD CONTINUE TO ADVECT INTO THE FORECAST AREA WITH GOOD
SOUTHEAST WINDS INCREASING TODAY.

WILL BE MONITORING LATEST MODEL RUNS...AS IT APPEARS THAT WESTERN
AND CENTRAL NORTH DAKOTA MAY HAVE A CHANCE OF STRONG TO SEVERE
STORMS LATE THIS EVENING INTO THE OVERNIGHT HOURS TONIGHT. CHANCES
OF THUNDERSTORMS ARE IN THE CURRENT FORECAST...BUT SEVERE WORDING
MAY BE NEEDED. SEE LATER UPDATES TODAY FOR ANY CHANGES REGARDING
SEVERE THUNDERSTORM OUTLOOKS. SEE STORM PREDICTION CENTER DAY 1
OUTLOOK FOR REFERENCE.

UPDATE ISSUED AT 636 AM CDT WED JUL 23 2014

PATCH OF SHOWERS CONTINUES ACROSS THE EAST CENTRAL NOW MOVING
INTO THE JAMESTOWN AREA. REFINED THE AREA OF SHOWERS/THUNDERSTORMS
FOR THE EARLY MORNING TO THE EAST CENTRAL AND JAMES RIVER VALLEY.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 340 AM CDT WED JUL 23 2014

FORECAST ISSUES IN THE SHORT TERM ARE THUNDERSTORM CHANCES.

WARM AIR ADVECTION WAS BEING AIDED BY A WEAK MID LEVEL VORTICITY
MAXIMA TO PRODUCE SOME CONVECTION BETWEEN WILLISTON AND BISMARCK
EARLY THIS WEDNESDAY MORNING. THE HIGH RESOLUTION MODELS HAVE BEEN
PICKING UP ON THIS AND THE LATEST RUNS INCREASE THE COVERAGE OF
THAT THROUGH MID MORNING BEFORE DISSIPATING STORMS AS THEY PUSH
EAST INTO LESS UNSTABLE AIR.

FOLLOWING THAT IS THE TIMING OF THE NEXT...MORE SIGNIFICANT...
WAVE FOR TONIGHT INTO THURSDAY.

THE H5 LONG WAVE RIDGE AXIS IS OVER THE MONTANA AND NORTH DAKOTA
BORDER LATE THIS AFTERNOON. THIS SHOULD SUPPRESS CONVECTION ON THE
NORTH DAKOTA SIDE...AND WEAKEN STORMS MOVING TOWARD THE BORDER
FROM MONTANA. THIS AXIS SHIFTS EAST AND IS BEATEN DOWN BY SHORT
WAVES IN THE UPSTREAM SOUTHWEST DIFFLUENT FLOW ALOFT. ALONG WITH
DEEPENING LOW PRESSURE AND AN INCREASING THERMAL RIDGE...THE
ATMOSPHERE OVER WESTERN NORTH DAKOTA DESTABILIZES SIGNIFICANTLY
OVERNIGHT TONIGHT WITH INCREASING STORM CHANCES.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 340 AM CDT WED JUL 23 2014

THE MAIN FEATURES IN THE EXTENDED PERIOD CONTINUE TO BE AN UPPER LOW
OFF THE WA/OR COAST AND ITS INTERACTION WITH THE DOWNSTREAM H500
RIDGE OVER THE NORTHERN PLAINS. AS THE UPPER LOW MOVES EAST AND
FLATTENS AND RAMS DOWN THE RIDGE...A COLD FRONT AT THE SURFACE
WILL POSITION ITSELF ACROSS EASTERN MONTANA BY THURSDAY AFTERNOON.
GFS APPEARS TO BE THE SLOWEST OF THE MODELS WITH THE NAM PROBABLY
THE FASTEST. THE ECMWF IS BETWEEN AND PROBABLY THE BEST FOR TIMING
THE FRONT INTO WESTERN NORTH DAKOTA BY 7 PM THURSDAY. NARROW BUT
STRONG THERMAL RIDGE AT H850 AND FRONTAL MIXING SHOULD ALLOW/SUPPORT
HIGH TEMPERATURES IN THE LOWER TO NEAR MIDDLE 90S ACROSS THE WEST
THURSDAY. THUNDERSTORMS...A FEW POSSIBLY SEVERE WITH STRONG WINDS
AND HAIL THE MAIN THREATS WILL ACCOMPANY THE FRONTS PROGRESSION INTO
THE STATE THURSDAY AFTERNOON AND EVENING. ON FRIDAY COOLER BUT STILL
REASONABLY MILD TEMPERATURES IN THE UPPER 70S TO LOWER 80S SHOULD BE
THE RULE. SHOWERS AND ISOLATED THUNDERSTORMS SHOULD BE LIMITED TO
THE EAST. ONE MORE DAY OF SHOWERS/SCATTERED THUNDERSTORMS ON
SATURDAY AS THE SLOW MOVING UPPER LOW TRACKS SOUTH ACROSS MINNESOTA.
WHILE THE STATE WILL GENERALLY BE ON THE DRY SIDE OF THE UPPER LOW
CANT RULE OUT SHOWERS AS COOL AIR ALOFT SHOULD SUPPORT SOME
INSTABILITY. AS THE UPPER LOW DRIFTS EAST AND RIDGE POPS UP IN
MONTANA SUNDAY THROUGH TUESDAY SHOULD BE DRY WITH GENERALLY PLEASANT
TEMPERATURES AND HUMIDITY FOR THIS TIME OF YEAR.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 120 PM CDT WED JUL 23 2014

LINGERING AREA OF MVFR CIGS EXTENDED FROM NEAR TIOGA AND STANLEY
AIRPORTS TO KMOT TO HEAR HARVEY AIRPORTS. EXPECTING MVFR CIGS TO
DISSIPATE SHORTLY AFT 18Z. OTHERWISE VFR CONDITIONS ALL TAF SITES
THROUGH 00Z-03Z. CHANCE OF TSRA AFT 03Z AT KISN...VCTS AT KDIK AFT
05Z...AND CHC -TSRA AFT 05Z AT KMOT/KBIS...AFT 06Z AT KJMS. STRONG
WINDS AND HAIL POSSIBLE AT KISN/KDIK/KMOT...BUT TOO FAR OUT IN THE
TAF PERIOD FOR ANY MORE SPECIFIC PARAMETERS.

&&

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

$$

UPDATE...JV
SHORT TERM...JPM
LONG TERM...WAA
AVIATION...JV