Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 021415
AFDBIS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
915 AM CDT SAT MAY 2 2015

.UPDATE...
ISSUED AT 911 AM CDT SAT MAY 2 2015

COLD FRONT IS NOW JUST NUDGING ITS WAY INTO FAR NORTHWESTERN NORTH
DAKOTA. LATEST HIGH-RES GUIDANCE SHOWS SHOWER AND THUNDERSTORM
DEVELOPMENT HOLDING OFF UNTIL AFTERNOON BEFORE ISOLATED ACTIVITY
INITIATES OVER CENTRAL NORTH DAKOTA. HAVE ADJUSTED POPS TO
REFLECT THIS. UPDATES HAVE BEEN SENT.

UPDATE ISSUED AT 637 AM CDT SAT MAY 2 2015

QUIET WEATHER PATTERN THIS SATURDAY MORNING. SOME HIGH CLOUDS WITH
SOUTHWEST WINDS AND TEMPERATURES MAINLY IN THE 40S. CURRENT
FORECAST LOOKS GOOD.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 355 AM CDT SAT MAY 2 2015

A PRE FRONTAL TROUGH FOLLOWED UP BY A COLD FRONTAL PASSAGE WILL
BE THE CATALYST FOR CRITICAL FIRE WEATHER CONDITIONS SATURDAY
AFTERNOON THROUGH EARLY SATURDAY EVENING. MAIN HIGHLIGHT IS A RED
FLAG WARNING FOR ALL OF WESTERN AND CENTRAL NORTH DAKOTA WITH THE
EXCEPTION OF THE FAR SOUTHWEST. ISOLATED THUNDERSTORMS WITH GUSTY
AND ERRATIC WINDS WILL FURTHER ENHANCE CRITICAL FIRE WEATHER
BEHAVIOR. SEE THE FIRE WEATHER SECTION BELOW FOR MORE DETAILS.

ALSO...ISOLATED SEVERE THUNDERSTORMS POSSIBLE IN SOUTH CENTRAL
NORTH DAKOTA THIS AFTERNOON AND EVENING. ANY THUNDERSTORM IS
CAPABLE OF PRODUCING WINDS TO 60 MPH AND HAIL UP TO ONE INCH IN
DIAMETER.

A NEAR ZONAL FLOW PER WATER VAPOR IMAGERY WITH THE MAIN SHORTWAVE
ACTIVITY SEEN ACROSS ALBERTA INTO SASKATCHEWAN. AT THE SURFACE...LOW
PRESSURE IN SOUTHWESTERN MANITOBA WITH A TRAILING COLD FRONT INTO
SOUTHERN SASKATCHEWAN AND ALBERTA. A PRE-FRONTAL TROUGH WAS
LOCATED IN EASTERN MONTANA. AS THIS FEATURE SHIFTS EAST TODAY AND
THE COLD FRONT APPROACHES DURING THE AFTERNOON...GUSTY SOUTHWEST
WINDS WILL INITIATE WITH WINDS SHIFTING TO THE WEST AND NORTHWEST
BEHIND THE COLD FRONT. ENOUGH INSTABILITY/MOISTURE EXISTS FOR
ISOLATED HIGH BASED THUNDERSTORMS/POSSIBLY SEVERE...TO INITIATE
ACROSS CENTRAL NORTH DAKOTA. INITIALLY...VIRGA/EVAPORATIONAL
COOLING OCCURRING UNDERNEATH THE HIGH BASED CUMULUS WILL FAVOR
GUSTY WINDS AT THE SURFACE. EVENTUALLY AS CLOUD BASES LOWER TO
AROUND 8KFT TO 10KFT...SHOWERS WILL MAKE THEIR WAY TO THE SURFACE.
LOW LEVEL MOISTURE REMAINS MEAGER WITH THIS SYSTEM SO NOT
EXPECTING MUCH PRECIPITATION AT THIS TIME. MAIN THREAT WILL BE
STRONG WINDS AND POSSIBLE HAIL. A SLIGHT CHANCE OF SHOWERS IS
FORECAST IN THE SOUTHWEST SATURDAY NIGHT WITH MOSTLY CLOUDY
CONDITIONS ELSEWHERE AS THE 850MB FRONT/BAROCLINIC ZONE SHIFTS
THROUGH.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 355 AM CDT SAT MAY 2 2015

THE EXTENDED PERIOD BEGINS SUNDAY WITH BROAD WESTERLIES ALOFT ACROSS
THE NORTHERN PLAINS. THIS FLOW BROUGHT THE COLD FRONTAL PASSAGE
THROUGH THE STATE SATURDAY NIGHT. IN ITS WAKE CLOUDS WILL CLEAR
FROM THE NORTH TO SOUTH DURING THE DAY. NORTHWEST FLOW OF 15 TO 25
MPH WILL AGAIN RAISE FIRE WEATHER CONCERNS ON SUNDAY WITH RELATIVE
HUMIDITY FALLING TO THE TEENS. EVEN THOUGH HIGHS WILL BE 10 TO 15
DEGREES COOLER ON SUNDAY THE DEWPOINTS WILL BE MIXING OUT AND
LOWERING INTO THE MIDDLE 20S. MONDAY AS WELL WILL BE DRY EXCEPT
FOR A SLIGHT CHANCE OF SHOWERS SOUTHWEST HOWEVER WINDS WILL NOT BE
AS MUCH OF A FACTOR. THINGS BEGIN TO CHANGE AND GET INTERESTING
TUESDAY THROUGH FRIDAY AS A MAJOR H500 TROUGH MOVES INLAND ACROSS
THE WESTERN US. THIS TROUGH ABSORBS AN UPPER LOW INTO THE GENERAL
SOUTHWEST FLOW ALOFT BY WEDNESDAY WHICH THEN MOVES AND PIVOTS
NORTH INTO THE NORTHERN PLAINS. BOTH GFS/ECMWF PORTRAY A WET
PATTERN ACROSS THE NORTHERN PLAINS WEDNESDAY AND THURSDAY. THIS
WILL BE THE FIRST REAL CHANCE FOR RAIN IN OVER A MONTH AND,
FINGERS CROSSED, WILL GIVE SUBSTANTIAL RAIN TO THE REGION BY THE
END OF THE WEEK.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 637 AM CDT SAT MAY 2 2015

VFR CIGS/VSBYS NEXT 24HR. A COLD FRONT WILL PUSH ACROSS WESTERN AND
CENTRAL NORTH DAKOTA THROUGH THE TAF PERIOD. ISOLATED SEVERE
THUNDERSTORMS COULD POSE AN AVIATION HAZARD WITH STRONG WINDS/HAIL
FROM KBIS TO KJMS SATURDAY AFTERNOON INTO EARLY EVENING. OTHERWISE
EXPECT WINDS SHIFTING FROM SOUTHWEST TO NORTHWEST AS THE COLD FRONT
MOVES THROUGH. WINDS WILL GUST TO BETWEEN 30 AND 35 MPH OUTSIDE OF
ANY THUNDERSTORM ACTIVITY.


&&

.FIRE WEATHER...
ISSUED AT 355 AM CDT SAT MAY 2 2015

VERY WARM TEMPERATURES...GUSTY WINDS TO 35 MPH...MINIMUM RELATIVE
HUMIDITIES BETWEEN 14 AND 20 PERCENT...AND A COLD FRONTAL PASSAGE...WILL
COMBINE TO PRODUCE CRITICAL FIRE WEATHER CONDITIONS SATURDAY AFTERNOON.
AS THE COLD FRONT MOVES ACROSS WESTERN AND CENTRAL NORTH DAKOTA
SATURDAY...WINDS WILL SHIFT FROM SOUTHWEST TO NORTHWEST. IN
ADDITION...ISOLATED THUNDERSTORMS ARE ALSO EXPECTED IN CENTRAL
NORTH DAKOTA AHEAD OF THE COLD FRONT...PRODUCING GUSTY AND ERRATIC
WINDS...WHICH WILL ENHANCE CRITICAL FIRE WEATHER BEHAVIOR. IF A
FIRE SHOULD IGNITE...EXPECT RAPID SPREAD.

ON SUNDAY...NORTHWEST WINDS OF 15 TO 25 MPH AND MINIMUM RELATIVE
HUMIDITY IN THE UPPER TEENS WILL AGAIN BRING ELEVATED FIRE
WEATHER CONCERNS ACROSS THE REGION.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING FROM 1 PM CDT /NOON MDT/ THIS AFTERNOON TO 8 PM
CDT /7 PM MDT/ THIS EVENING FOR NDZ001>005-009>013-017>023-025-
031>037-042-045>048-050-051.

&&

$$

UPDATE...JJS
SHORT TERM...KS
LONG TERM...WAA
AVIATION...WAA/KS
FIRE WEATHER...KS



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