000
FXUS63 KBIS 251307
AFDBIS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
807 AM CDT SAT MAY 25 2013

.UPDATE...
ISSUED AT 805 AM CDT SAT MAY 25 2013

QUICK UPDATED TO ADD A MENTION OF A MORNING SHOWER OR THUNDERSTORM
IN THE WEST. CURRENTLY CONVECTION ALONG THE MT/ND BORDER AND
LIFTING NORTHEAST. ALSO BUMPED UP SKY COVER A BIT IN THE WEST AND
ALSO FARTHER EAST WHERE EXTENSIVE FOG REMAINS.

UPDATE ISSUED AT 649 AM CDT SAT MAY 25 2013

UPDATED THE FORECAST TO INCREASE FOG COVERAGE ACROSS WESTERN AND
CENTRAL NORTH DAKOTA. SOME SITES ARE REPORTING DENSE FOG AT TIMES.
HOWEVER...DENSE FOG IS NOT WIDESPREAD. AS A RESULT...DECIDED TO HOLD
OFF ON ISSUING A DENSE FOG ADVISORY AT THIS TIME.

OTHERWISE...THE REMAINING WEATHER ELEMENTS ARE IN GOOD SHAPE. ONLY
MODIFIED THE HOURLY SENSIBLE WEATHER GROUPS BASED ON CURRENT
OBS/TRENDS. THE UPDATED GRIDDED AND TEXT PRODUCTS HAVE BEEN SENT.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 429 AM CDT SAT MAY 25 2013

FOG IS THE FIRST ISSUE IN THE SHORT TERM. PATCHY FOG...SOME OF IT
DENSE...HAS FORMED OVERNIGHT IN THE MOIST SOUTHEAST FLOW. HAVE
EXPANDED THE FOG AREAS FROM THE PREVIOUS FORECAST ACROSS THE
ENTIRE FORECAST AREA FOR EARLY THIS MORNING. POTENTIAL ISSUE IS IT
NOT LIFTING UNTIL CONVECTION GETS GOING...WHICH WOULD THEN AFFECT
HIGH TEMPERATURE FORECAST.

CONVECTION IS THE NEXT AND MORE PRESSING ISSUE. SOUTHEAST MOIST
FLOW WAS PUSHING DEW POINT TEMPERATURES UP INTO THE FAVORABLE
RANGE...ABOVE 50...FOR SIGNIFICANT DESTABILIZATION OF THE
ATMOSPHERE. SOUTHWEST FLOW ALOFT WILL BRING MID LEVEL ENERGY INTO
SOUTHWEST NORTH DAKOTA BY EARLY AFTERNOON. THE MOST UNSTABLE
AIR...ALONG WITH A LOW LEVEL SPEED MAX...IS FORECAST TO BE OVER
THE SOUTHWEST PART OF THE AREA WITH SEVERE WEATHER POSSIBLE
THERE...IN THE FORM OF LARGE HAIL...HIGH WINDS...AND HEAVY RAIN.
HIGHLIGHTED AREA FOR SEVERE WEATHER IS FROM WATFORD
CITY...THROUGH KILLDEER...DICKINSON...AND ELGIN...TO
HETTINGER...AND WEST TO THE MONTANA BORDER. STORMS ARE SLOW TO
MOVE NORTHEAST AND ARE FORECAST TO WEAKEN AS THEY MOVE INTO A LESS
UNSTABLE REGIME.

ANOTHER MID LEVEL WAVE ENTERS THE WEST OVERNIGHT WITH A
REINFORCING SHOT OF STORMS.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 429 AM CDT SAT MAY 25 2013

THE MAIN FORECAST CONCERN FOR THE EXTENDED WILL BE THE CHANCES
FOR SEVERE THUNDERSTORMS ACROSS SOUTHWESTERN NORTH DAKOTA SUNDAY
AFTERNOON/EVENING.

LOW-LEVEL MOISTURE ADVECTION IS PROGGED TO CONTINUE ACROSS WESTERN
AND CENTRAL NORTH DAKOTA SUNDAY. THIS COMBINED WITH TEMPERATURES
IN THE LOW 70S WILL LEAD TO INCREASING INSTABILITY (MUCAPE VALUES
UP TO 1000 J/KG) ACROSS SOUTHWESTERN NORTH DAKOTA SUNDAY AFTERNOON
AND EVENING. AT THE SAME TIME...DEEP LAYER BULK SHEAR VALUES
AROUND 35 KNOTS ARE PROGGED TO DEVELOP ACROSS THE REGION. THE
FAVORABLE MOISTURE/INSTABILITY/AND SHEAR PROFILES WARRANT
MENTIONING THE POTENTIAL FOR SEVERE WEATHER ACROSS SOUTHWESTERN
NORTH DAKOTA SUNDAY AFTERNOON/EVENING. THIS LINES UP WELL WITH THE
DAY 2 SPC CONVECTIVE OUTLOOK AND SURROUNDING OFFICES.

FOR MONDAY AND BEYOND...THE UNSETTLED WEATHER PATTERN WILL CONTINUE.
THE MEDIUM RANGE MODEL SOLUTIONS DIFFER WITH RESPECT TO THE THE
TIMING AND LOCATION OF PRECIPITATION CHANCES THROUGH THE PERIOD.
HOWEVER...THE MODELS ARE CONSISTENT WITH THE OVERALL SYNOPTIC
PATTERN OF SOUTHWESTERLY FLOW ALOFT TRANSITIONING TO A CUT OFF LOW
OVER THE NORTHERN PLAINS BY THE END OF THE WEEK. GIVEN THE MODEL
DIFFERENCES...CONTINUED TO UTILIZE A BLEND OF SOLUTIONS THROUGH THE
PERIOD.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 805 AM CDT SAT MAY 25 2013

FOG HAS DEVELOPED AT MOST TAF SITES IN RESPONSE TO A MOIST SOUTHEAST
FLOW INTO THE AREA. THUNDERSTORMS ARE FORECAST TO BREAK OUT IN THE
SOUTHWEST...KDIK...AND SPREAD NORTHEAST TODAY...REACHING KJMS
AFTER 26/00Z. SOME STORMS SOUTHWEST COULD PRODUCE LARGE HAIL AND
HIGH WINDS BETWEEN 25/21Z AND 26/03Z.


&&

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

$$

UPDATE...TWH
SHORT TERM...JPM
LONG TERM...TM
AVIATION...TWH