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000
FXUS63 KBIS 291722
AFDBIS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
1222 PM CDT TUE JUL 29 2014

.UPDATE...
ISSUED AT 1215 PM CDT TUE JUL 29 2014

GOING FORECAST IN GOOD SHAPE AS IT CONTINUES TO ADDRESS SOME LOW
PRECIP CONCERNS WITH SMALL EDDY PUSHING THROUGH UPPER FLOW
APPROACHING NORTH CENTRAL NORTH DAKOTA. ONLY CHANGE WAS TO ADDRESS
CLOUD COVER AS CU FIELD CONTINUES TO DEVELOP OVER CENTRAL/EASTERN
NORTH DAKOTA IN WEAK CYCLONIC FLOW. UPDATES HAVE BEEN SENT.

UPDATE ISSUED AT 834 AM CDT TUE JUL 29 2014

WATER VAPOR IMAGERY CONTINUES TO SHOW DISTINCT EDDY SLIDING SOUTH
ALONG THE MANITOBA/SASKATCHEWAN BORDER. HIGH RES MODELS CONTINUE TO
SHOW SOME PRECIP POSSIBLY DEVELOPING AS IT MOVES THROUGH CENTRAL
NORTH DAKOTA. THEREFORE...HAVE EXPANDED LOW POPS A BIT TO ACCOUNT
FOR THIS FEATURE. REMAINDER OF FORECAST REMAINS ON TRACK.

UPDATE ISSUED AT 642 AM CDT TUE JUL 29 2014

NO CHANGES REQUIRED WITH THIS UPDATE OTHER THAN TO BLEND TO
OBSERVED TRENDS THROUGH 1130 UTC. THE 06 UTC NAM CONTINUES THE
TREND OF THE 00 UTC WRF-ARW AND NMM OF ISOLATED SHOWERS AND
POSSIBLY A THUNDERSTORM CENTRAL IN ASSOCIATION WITH THE DISTINCT
EDDY EVIDENT ON WATER VAPOR IMAGERY ACROSS SOUTHEAST SASKATCHEWAN
THAT WILL CONTINUE TO PROPAGATE SOUTHEAST INTO NORTH DAKOTA.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 236 AM CDT TUE JUL 29 2014

MAIN CHALLENGE IN THE SHORT TERM WILL BE AN ISOLATED
SHOWER/THUNDERSHOWER ACROSS A PORTION OF CENTRAL NORTH DAKOTA
TUESDAY AFTERNOON IN RESPONSE TO A SHORTWAVE SLIDING THROUGH VIA A
NORTHWEST FLOW AND SUFFICIENT INSTABILITY IN PLACE.

FOR THE NEAR TERM...WILL CONTINUE WITH PATCHY TO AREAS OF FOG AS
TEMPERATURE AND DEWPOINT SPREADS ARE AT OR NEAR ZERO WITH CALM
WINDS. FOG STRATUS LOOP CONTINUES TO INDICATE POCKETS OF LOWER
CLOUDS AND EXPECT THIS TO INCREASE IN COVERAGE UNTIL
SUNRISE...THEN DISSIPATE SHORTLY THEREAFTER.

THE LATEST WATER VAPOR IMAGERY SHOWS A NICELY DEFINED SHORTWAVE
SLIDING SOUTH ALONG THE SASKATCHEWAN/MANITOBA BORDER. WEAKER
SHORTWAVES WERE ALSO SEEN JUST UPSTREAM INTO NORTH CENTRAL
SASKATCHEWAN. ANOTHER PUSH OF MOISTURE IN THE 850MB TO 700MB LAYER
WILL ENSUE AHEAD OF THESE SHORTWAVES. THE COMBINATION OF THESE
SHORTWAVES WILL CONTRIBUTE TO AN UNSTABLE ENVIRONMENT ACROSS
CENTRAL NORTH DAKOTA. THE NAM/GFS SOUNDINGS INDICATE CAPE IN THE
RANGE OF 500 TO 800 J/KG FROM MINOT TO BISMARCK...LIFTED INDICES
AROUND 0C...AND 0-6KM SHEAR AT 25KT. THE NAM AND ASSOCIATED HIGH
RESOLUTION MODELS INDICATE SOME CONVECTION FROM NEAR MAX TO LINTON
THIS AFTERNOON. THIS HAS SUPPORT ALSO FROM THE ECMWF...WHILE THE
GFS ALSO SHOWS AN UNSTABLE ENVIRONMENT BUT DOES NOT GENERATE QPF.
WILL INTRODUCE AN ISOLATED SHOWER/THUNDERSHOWER INTO THE GRIDS
WITH THIS FORECAST AS THERE IS ENOUGH EVIDENCE TO SUPPORT
SOMETHING DEVELOPING BETWEEN 18Z AND 00Z. HIGHS TODAY WILL RANGE
FROM 75F TO 85. PARTLY CLOUDY TO MOSTLY CLEAR TONIGHT WITH
OVERNIGHT LOWS IN THE 50S.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 236 AM CDT TUE JUL 29 2014

A DRY AND SEASONABLE TEMPERATURE PATTERN WILL HIGHLIGHT THE
EXTENDED FORECAST.

THE 00 UTC DETERMINISTIC AND ENSEMBLE SUITES ARE IN AGREEMENT ON THE
NORTHERN PLAINS REMAINING DOWNSTREAM OF THE UPPER LEVEL RIDGE AXIS
ACROSS THE INTERMOUNTAIN WEST THROUGH THURSDAY. THEREAFTER...THE
RIDGE IS FORECAST TO DE-AMPLIFY INTO THE WEEKEND. THIS LARGE SCALE
PATTERN SUPPORTS A SLOWLY WARMING TREND INTO THE MID TO UPPER 80S
INTO THE WEEKEND UNDER A MUCH BROADER UPPER LEVEL RIDGE...COMPARED
TO NORTHWEST FLOW ALOFT WEDNESDAY AND THURSDAY. WITH THE BROAD
UPPER LEVEL RIDGE...SLIGHT CHANCE TO CHANCE POPS ARE ARE
INTRODUCED FOR THE WEEKEND TO ACCOUNT FOR RIDGE RUNNING
SHORTWAVES.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1215 PM CDT TUE JUL 29 2014

ISOLD -SHRA/-TSRA WILL BE POSSIBLE THROUGH EARLY EVENING OVER
CENTRAL NORTH DAKOTA. OTHERWISE...VFR CONDITIONS WILL PREVAIL.

&&

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

$$

UPDATE...JJS
SHORT TERM...KS
LONG TERM...AYD
AVIATION...JJS