Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 201946
AFDBIS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
ISSUED BY NATIONAL WEATHER SERVICE GRAND FORKS ND
246 PM CDT WED AUG 20 2014

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 244 PM CDT WED AUG 20 2014

SEVERE THUNDERSTORM POTENTIAL AND HEAVY RAINFALL WILL HIGHLIGHT
THE SHORT TERM FORECAST.

LITTLE CHANGE FROM THE PREVIOUS UPDATE. THE BEST POTENTIAL FOR
SEVERE CONVECTION REMAINS ALONG AND EAST OF THE HIGHWAY 83
CORRIDOR WHERE FILTERED SUNSHINE THROUGH MID TO HIGH LEVEL CLOUD
COVER HAS ALLOWED FOR TEMPERATURES TO WARM INTO THE LOWER
80S...AMID A MOIST AIRMASS WITH DEW POINTS GENERALLY IN THE UPPER
60S. SOME WEAK ML INHIBITION REMAINS...WHICH LEADS TO UNCERTAINTY
IF THE BOUNDARY LAYER CAN HEAT OUT GIVEN THE AFOREMENTIONED CLOUD
COVER. EFFECTIVE DEEP LAYER SHEAR IS MARGINAL...ON THE ORDER OF
THE 25-30 KTS...SUPPORTING A POSSIBLE SUPERCELL OR TWO IF
INHIBITION CAN BE OVER COME. GREATER CONVECTIVE STRENGTHENING
LOOKS TO BE DELAYED UNTIL 21-00 UTC WITH GREATER LOW LEVEL
CONVERGENCE AHEAD OF THE COLD FRONT PROPAGATING THROUGH WESTERN
NORTH DAKOTA. IN ADDITION TO LARGE HAIL AND DAMAGING WINDS...HEAVY
RAIN WILL ALSO BE A PRIMARY THREAT AS CORFIDI VECTORS REMAIN SLOW
BETWEEN 10 AND 20 KTS...WITH CONTINUED INCREASING LOW LEVEL
MOISTURE TRANSPORT. FINALLY...CONTINGENT UPON SEVERE CONVECTIVE
DEVELOPMENT...AN ISOLATED TORNADO CANNOT BE RULED OUT WITH 0-1 KM
SHEAR OF 15-20 KTS AHEAD OF THE FRONT. STORMS WILL PROPAGATE EAST
THROUGH THE EVENING...WITH THE SEVERE THREAT WANING AFTER SUNSET.
A BRIEF LULL IN PRECIPITATION MAY BE IN STORE FOR MUCH OF WESTERN
AND CENTRAL NORTH DAKOTA ON THURSDAY WITH WEAK SHORTWAVE RIDGING
ALOFT BEFORE THE WET PATTERN IN THE EXTENDED.


.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 244 PM CDT WED AUG 20 2014

ACTIVE SOUTHWESTERLY FLOW CONTINUES THROUGH THE MAJORITY OF THE
EXTENDED KEEPING PRECIPITATION CHANCES IN THE FORECAST. MAJOR
CONCERN IS GOING INTO THE END OF THE WORK WEEK INTO THE WEEKEND AS
MODELS CONTINUE THEIR CONSISTENCY WITH GENERALLY HIGH QPF...WHICH IF
THIS COMES TO FRUITION MAY RESULT IN SOME HYDRO CONCERNS. NATIONAL
GUIDANCE KEEPS THE HIGHEST QPF VALUES THROUGH THE WEEKEND MAINLY
OVER WESTERN NORTH DAKOTA...BUT A SLIGHT SHIFT IN THE MODELS
SOLUTIONS OVER THE NEXT COUPLE DAYS COULD BRING THE CONCERNS FURTHER
EAST. WILL HAVE TO WATCH THIS CLOSELY. AS FOR TEMPERATURES...COOLER
AIRMASS WILL START TO SINK IN FRIDAY WITH WELL BELOW AVERAGE
TEMPERATURES EXPECTED BY THE WEEKEND...CONTINUING INTO EARLY NEXT
WEEK.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 244 PM CDT WED AUG 20 2014

SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE EXPECTED THIS
AFTERNOON AND THROUGH THE EVENING AT ALL TAF SITES AS A COLD FRONT
MOVES ACROSS THE STATE. EMBEDDED MVFR AND IFR CONDITIONS ARE
FORECAST. SEE TAFS FOR THUNDERSTORM TIMING AND IMPACTS

&&

.HYDROLOGY...
ISSUED AT 244 PM CDT WED AUG 20 2014

HYDROLOGIC CONCERNS ARE CENTERED UPON THE STRONG STORM SYSTEM
FORECAST TO IMPACT THE NORTHERN PLAINS SATURDAY AND SUNDAY. WHILE
HEAVY RAINFALL IS CERTAIN...ITS EXACT PLACEMENT WILL REMAIN A BIT
UNCERTAIN OVER THE NEXT 24 TO 36 HOURS AS THE MODEL TRACKS
CONTINUE TO WOBBLE A BIT. GIVEN UNCERTAINTY...WILL HOLD OFF ON A
WATCH FOR NOW AND HIGHLIGHT THE POTENTIAL CONCERNS IN THE HWO AND
ISSUE AN SPS.

&&

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

$$

SHORT TERM...AYD
LONG TERM...JJS
AVIATION...AYD
HYDROLOGY...AYD





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