Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 052051
AFDBIS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
351 PM CDT TUE MAY 5 2015

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 248 PM CDT TUE MAY 5 2015

FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE INCREASING
CHANCES FOR RAIN LATE TONIGHT INTO WEDNESDAY ALONG WITH SCATTERED
THUNDERSTORMS...BRINGING A WELCOMED SHOT OF MODERATE TO HEAVY
RAINFALL.

CURRENTLY...SOUTHEAST TO NORTHWEST ORIENTATED UPPER LEVEL RIDGE
AXIS MOVING EAST ACROSS THE NORTHERN PLAINS...WITH A STRONG UPPER
LEVEL S/WV TROUGH LIFTING SLOWLY NORTHEAST INTO THE CENTRAL
ROCKIES. FRONTAL BOUNDARY CONTINUES TO DEVELOP ACROSS EASTERN
MONTANA...RESULTING IN A TIGHT PRESSURE GRADIENT ACROSS THE
DAKOTAS. BREEZY SOUTH-SOUTHEAST LOW/MID LEVEL FLOW TRANSPORTING
MOISTURE INTO THE REGION WITH TDS CLIMBING INTO THE 40S WEST. DRY
CONDITIONS PERSIST EAST WHERE FIRE WEATHER HEADLINES REMAIN IN
PLACE. SEE FIRE WEATHER DISCUSSION BELOW.

FLOW ALOFT WILL TRANSITION TO SOUTHERLY TONIGHT ALLOWING FOR LEAD
S/WV IMPULSES ORIGINATING FROM THE CENTRAL ROCKIES UPPER WAVE TO
PUSH NORTH ACROSS SOUTH DAKOTA AND EVENTUALLY INTO NORTH DAKOTA.
MODELS HOLD OFF ON QPF TILL AFTER 06Z WHEN THE MORE FAVORABLE
FORCING ARRIVES...BUT COULD STILL SEE A STRAY SHOWER OR TWO THIS
EVENING SOUTH. LOW LEVEL CIGS WILL DEVELOP NORTH ACROSS WESTERN
AND CENTRAL ND TONIGHT INTO WED MORNING WITH CONTINUED MOISTURE
ADVECTION AND A EAST/SOUTHEASTERLY UPSLOPE FLOW REGIME. WILL
MAINTAIN A SLIGHT CHANCE FOR THUNDERSTORMS OVERNIGHT MAINLY SOUTH
WHERE THE 12Z EC/GFS INDICATE 2-4 HUNDRED J/KG OF MUCAPE.

FRONTAL BOUNDARY SHIFTS EASTWARD ACROSS WESTERN ND WEDNESDAY
MORNING AND INTO CENTRAL ND WED AFTERNOON. THIS WILL COINCIDE WITH
2-3 MORE EMBEDDED IMPULSES LIFTING NORTH ACROSS THE DAKOTAS BEFORE
THE MAIN WAVE MOVES THROUGH WED NIGHT. WIDESPREAD RAINFALL SHOULD
BE EXPERIENCED IN THE MORNING AND AFTERNOON WITH HIGHER AMOUNTS IN
PROXIMITY TO THE FRONTAL BOUNDARY AS IT MOVES SLOWLY FROM WEST TO
EAST ACROSS THE STATE...WITH STORM TOTAL AMOUNTS STILL DEPICTED
FROM 0.5-1.3 INCHES. WITH BOTH THE 12Z GFS/ECMWF GENERATING
900-1200 J/KG OF MUCAPE OVER MY CENTRAL AND EAST ALONG TO EAST OF
THE FROPA...LOCALLY HEAVIER RAINFALL (GREATER THAN AN INCH) WITH
CONVECTION WILL BE VERY POSSIBLE CONSIDERING PWATS AROUND 1.25"
ARE AROUND THE 99TH PERCENTILE FOR EARLY MAY.

DEEP LAYER WIND SHEAR WED AFTERNOON WILL BE LACKING WITH MODELS
ONLY GENERATING 15-20KTS ON AVERAGE...THUS THE POTENTIAL FOR ANY
SEVERE CONVECTION APPEARS LOW. STILL...THE STRONG FORCING
ASSOCIATED WITH THE MAIN UPPER WAVE MAY BE ENOUGH TO OVERCOME THIS
SO WILL BE SOMETHING TO KEEP AN EYE ON.

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 248 PM CDT TUE MAY 5 2015

WIDESPREAD RAINFALL AND SCATTERED THUNDERSTORMS HIGHLIGHT THE
LONG TERM FORECAST.

WIDESPREAD RAINFALL WILL PERSIST THROUGH THE OVERNIGHT HOURS
WEDNESDAY. RAIN WILL DIMINISH FROM WEST TO EAST THROUGH THE DAY
THURSDAY. SOME ISOLATED TO SCATTERED THUNDERSTORMS ARE POSSIBLE
WEDNESDAY NIGHT ACROSS CENTRAL NORTH DAKOTA WHERE DEEP MOISTURE
CONVERGENCE AND UPPER LEVEL INSTABILITY COINCIDE. THE THREAT FOR
THUNDERSTORMS WILL RAPIDLY DIMINISH THURSDAY AS COLD AIR ADVECTION
AND DRIER AIR MOVES IN...ELIMINATING INSTABILITY.

WE WILL SEE A BRIEF BREAK IN THE RAIN FRIDAY. TEMPERATURES IN THE
LOW TO MID 30S COULD PRODUCE SOME FROST ACROSS THE REGION FRIDAY
MORNING AND EACH MORNING THEREAFTER.

ANOTHER LOW WILL PIVOT AROUND COLORADO THIS WEEKEND. THIS WILL PUT
NORTH DAKOTA ON THE FRINGES OF RAIN SHOWERS SATURDAY MORNING
THROUGH EARLY NEXT WEEK. THE BEST CHANCE FOR WIDESPREAD RAINFALL
WILL ARRIVE SUNDAY EVENING AS THE LOW EJECTS OUT INTO THE UPPER
MISSISSIPPI VALLEY. AT THIS TIME THE CONSENSUS BETWEEN THE MODELS
PUTS THE GREATEST PRECIPITATION (AROUND HALF AN INCH OR SO) ACROSS
THE JAMES AND RED RIVER VALLEYS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)

ISSUED AT 248 PM CDT TUE MAY 5 2015

LOW PRESSURE SYSTEM APPROACHING WESTERN NORTH DAKOTA WILL MAINTAIN
A BREEZY SOUTHEAST WIND THROUGH THE DAY TODAY. LOW CLOUD COVER
WILL INCREASE TONIGHT WITH MVFR AND POTENTIALLY IFR CEILINGS
SPREADING NORTH ACROSS THE REGION AND PERSISTING WEDNESDAY
MORNING. A CHANCE OF RAIN SOUTH 06Z-12Z AT KDIK...KBIS...AND KJMS.
WIDESPREAD RAINFALL WEDNESDAY MORNING - WEDNESDAY NIGHT. SCATTERED
THUNDERSTORMS WILL ALSO BE POSSIBLE...THOUGH CONFIDENCE NOT HIGH
ENOUGH TO PUT IN ANY TAF AT THIS TIME.


&&

.FIRE WEATHER...

ISSUED AT 248 PM CDT TUE MAY 5 2015

WILL EXPAND THE RED FLAG WARNING SOUTH AND WEST A BIT.

RELATIVE HUMIDITY AS LOW AS 20 PERCENT AND STRONG WINDS GUSTING
UP TO 30 MPH ARE BEING OBSERVED ALONG TO EAST OF THE MISSOURI
RIVER...WITH DRY CONDITIONS IN PLACE TO CREATE CRITICAL FIRE
WEATHER CONDITIONS. CONDITIONS WILL QUICKLY IMPROVE EARLY TO MID
EVENING.


&&

.BIS WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 7 PM CDT THIS EVENING FOR NDZ003>005-
011>013-019>023-025-035>037-046>048-050-051.

&&

$$

SHORT TERM...NH
LONG TERM...AJ
AVIATION...NH
FIRE WEATHER...NH


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