Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 211554
AFDBIS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
1054 AM CDT MON JUL 21 2014

.UPDATE...
ISSUED AT 1053 AM CDT MON JUL 21 2014

EARLY UPDATE...LINE OF SHOWERS AND THUNDERSTORMS HAVE DEVELOPED
OVER NORTHEAST MONTANA...AND ARE MOVING NORTHEAST. OTHER AREAS OF
SHOWERS DEVELOPING OVER SOUTHWEST NORTH DAKOTA AND FAR SOUTHERN
NORTH DAKOTA. MONITORING THESE AREAS CLOSELY. THE MAIN TIMING FOR
SEVERE WEATHER IS STILL ON TRACK...IN THE WEST BETWEEN 18Z AND
21Z...CENTRAL 21Z TO 01Z.

UPDATE ISSUED AT 740 AM CDT MON JUL 21 2014

LATEST WATER VAPOR IMAGERY SHOWS SEVERAL SHORTWAVES EMBEDDED
WITHIN A SOUTHWEST FLOW FROM SOUTHWEST MONTANA INTO CENTRAL/EASTERN
IDAHO...MOVING NORTHEAST TOWARD WESTERN NORTH DAKOTA. A 55KT JET
WAS SEEN PUNCHING THROUGH UTAH AND WYOMING...WHICH WILL FURTHER
ENHANCE LARGE SCALE ASCENT THIS AFTERNOON AND EVENING. FOCUS AND
SITUATIONAL AWARENESS COMPLETELY ON MONITORING SEVERE WEATHER
THROUGH THE DAY AND EVENING.

CURRENT REGIONAL/LOCAL RADAR SHOWS SHOWERS AND THE ISOLATED
THUNDERSTORMS OVER SOUTHERN MONTANA AND INTO CENTRAL AND NORTHERN
WYOMING. THE LATEST HRRR SEEMS TO HAVE A DEVELOPING AREA NEAR
SHERIDAN WYOMING HANDLED WELL. THE HRRR SUGGESTS THAT CONVECTION
COULD INITIATE BETWEEN 18Z AND 21Z ALONG A LINE FROM NEAR WATFORD
CITY TO DICKINSON...AND THEN MOVE TO A MINOT TO BISMARCK LINE
BETWEEN 21Z AND 00Z. THE OTHER HIGH RESOLUTION MODELS ARE SIMILAR
IN THE AREA DEVELOPMENT...BUT ARE MORE INTENSE WITH THE AREA AND
ARE QUICKER IN THE OVERALL EASTWARD MOVEMENT LATER THIS AFTERNOON.
WILL CONTINUE TO INTERROGATE SATELLITE/RADAR AND HIGH RESOLUTION
AND MODELS THROUGH THE MORNING.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 429 AM CDT MON JUL 21 2014

THE MAIN FORECAST CHALLENGE TODAY IS SEVERE WEATHER TIMING. THE
LATEST CONVECTION-ALLOWING MODELS CALL FOR EARLY AFTERNOON
CONVECTIVE INITIATION GENERALLY ALONG AND WEST OF U.S. 83.
EASTWARD PROPAGATION OF AN MCS ALONG INTERSTATE 94 IS THE
CONSENSUS SOLUTION...AND IT MATCHES THE STORM PREDICTION CENTER
MODERATE RISK AREA WELL.

THE 21/00 UTC HIRES ARW AND NMM CALL FOR CONVECTIVE INITIATION EVEN
FURTHER WEST AROUND NOON...AND BOTH CALL FOR A LARGE BOW ECHO TO
BE SOMEWHERE BETWEEN GLEN ULLIN AND BISMARCK BY 4 PM CDT. WITH THE
INITIATION AREA MOVING WEST...THE MODERATE RISK AREA MAY HAVE TO
SHIFT A LITTLE WESTWARD. THE STORM PREDICTION CENTER HAS REQUESTED
AN 18 UTC BALLOON BE LAUNCHED...WHICH SHOULD PROVIDE SOME INSIGHT
INTO HOW EXTREME THE INSTABILITY HAS BECOME BY THEN.

BE SURE TO SEE THE DAY 1 STORM PREDICTION CENTER CONVECTIVE
OUTLOOK GRAPHIC AND DISCUSSION FOR MORE DETAILS.

FINALLY...A HEAT ADVISORY WAS ISSUED FOR THREE SOUTHEASTERN
COUNTIES. THE SURFACE LOW TRACK HAS SHIFTED NORTHWARD IN THE PAST
36 HOURS OF MODEL RUNS. CONSEQUENTLY...THE WARM SECTOR HAS ALSO
SHIFTED NORTH. HEAT INDICES UP TO 105F ARE NOW FORECAST.

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 429 AM CDT MON JUL 21 2014

A BRIEF UPPER LEVEL FLOW PATTERN SHIFT FROM PROGRESSIVE TO BLOCKED
OVER THE SOUTHERN TIER OF CANADA DOES NOTHING TO SQUELCH CHANCES
FOR CONVECTION IN THE FORECAST UNTIL SUNDAY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1053 AM CDT MON JUL 21 2014

THUNDERSTORMS WILL DEVELOP ACROSS THE WESTERN TERMINALS THROUGH
21Z AND THEN INTO THE CENTRAL TERMINALS..KBIS/KMOT BETWEEN 21Z
AND 01Z. KJMS CLOSER TO 00Z TUESDAY. SOME THUNDERSTORMS WILL BE
SEVERE WITH DAMAGING WINDS AND LARGE HAIL.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY UNTIL 9 PM CDT THIS EVENING FOR NDZ048-050-051.

&&

$$

UPDATE...KS
SHORT TERM...SCHECK
LONG TERM...SCHECK
AVIATION...KS






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