Area Forecast Discussion
Issued by NWS Grand Forks, ND

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FXUS63 KFGF 250454
AFDFGF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND FORKS ND
1154 PM CDT THU JUL 24 2014

.UPDATE...
ISSUED AT 1153 PM CDT THU JUL 24 2014

CONVECTION CONTINUES OVER NORTHWEST SD WHERE TEMPS WERE QUITE WARM
ALOFT. LIGHTNING STRIKES MAINTAIN THEIR NUMBERS OVER SD WHILE OVER
ND THE STRIKES HAVE DECREASED IN THE LAST HOUR OR TWO. STORMS HAVE
BEEN MOVING EAST AT 40 TO 45 KNOTS. VAD WINDS SUGGEST LOW LEVEL JET
MAY BE FARTHER WEST THAN THE MODELS WHICH IS KEEPING SD STORMS
GOING. ALSO A LINE OF PRECIP WAS DEVELOPING FROM NORTH OF JMS TO
SOUTH OF FAR.

WATER VAPOR LOOP SUGGESTS A SHORT WAVE WAS MOVING ACROSS ND AND SD
AND WAS KNOCKING DOWN RIDGE AXIS.

SURFACE LOW WAS LOCATED SOUTHWEST OF PIR WITH TROUGH EXTENDING INTO
WESTERN ND. SURFACE TROUGH WILL MOVE ACROSS THE FORECAST AREA BY FRI
AFTERNOON.

UPDATE ISSUED AT 944 PM CDT THU JUL 24 2014

WATER VAPOR LOOP INDICATED UPPER LEVEL LOW PRESSURE SYSTEM WAS OVER
SOUTHERN ALTA. UPPER LEVEL SYSTEM WILL DRIVE A COLD FRONT ACROSS THE
WESTERN DAKOTAS LATE TONIGHT AND INTO THE FORECAST AREA FRI.

PRECIPITABLE WATER RISES TO AROUND AN INCH AND A HALF BY MORNING.
GOOD SURFACE MIXING RATIOS PRECEDE FRONTAL SYSTEM IN THE WEST.
HOWEVER NOT MUCH OF A LOW LEVEL JET FORECAST PRECEDES FRONT FOR
TONIGHT. HOWEVER STRONGER JET IS OUT OF THE NORTHWEST AND IS POST
FRONTAL.

MODELS INDICATE TWO 700 THETA-E RIDGES OVER THE FORECAST AREA AND
THE OTHER IN WESTERN ND/EASTERN MT. MODEL SOUNDINGS INDICATE 850 HPA
DEWPOINTS INCREASE OVERNIGHT IN SOUTHEAST ZONES. RADAR INDICATING
PRECIP TRYING TO DEVELOP OVER SOUTHEAST ZONES. BOTH GFS AND ECMWF
DEVELOP PRECIP OVER SOUTHEAST ZONES. WILL INCREASE POPS IN SOUTHEAST
ZONES.

UPDATE ISSUED AT 700 PM CDT THU JUL 24 2014

RADARS INDICATED BAND OF PRECIP MOVING INTO BARNES, GRIGGS, AND
NELSON COUNTIES. PRECIP WAS MOVING EAST ABOUT 50 KNOTS. LIGHTNING
NETWORK INDICATED ACTIVITY HAS DECREASED TO NO RECENT LIGHTNING
STRIKES. EXPECT PRECIP TO CONTINUE MOVING EAST AND DISSIPATING. NO
CHANGES MADE TO CURRENT FORECAST.

&&

.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 315 PM CDT THU JUL 24 2014

FORECAST CHALLENGE CONCERNS T CHANCES AND TEMPERATURES. MODELS IN
FAIR AGREEMENT HOWEVER SHOWING DIFFERENCES IN PCPN COVERAGE
LOCATION WITH NEXT SHORT WAVE. AT THIS POINT ECMWF HAVING BEST
HANDLE ON CURRENT RAIN LOCATION SO WILL FOLLOW IN THE NEAR TERM.

SHORTWAVE TO ROTATE AROUND UPPER LOW TONIGHT WHICH WILL REACH
WESTERN CANADIAN PRAIRIE PROVINCES BY MORNING. THIS FEATURE SHOULD
INTERACT WITH SURFACE LOW/FRONTAL BOUNDARY IN EASTERN MT TO
INITIATE ANOTHER ROUND OF DEEP CONVECTION. CURRENTLY THERE IS SOME
CAPPING HOWEVER APPROACHING WAVE SHOULD BREAK CAP WITH STORMS
BECOMING MORE ORGANIZING ALONG MT/DAKOTAS BORDER THIS EVENING
PROPAGATING EAST OVERNIGHT. LOW LEVEL JET NOT ALL THAT IMPRESSIVE
AT LEAST FROM MODEL SOLUTIONS HOWEVER ENOUGH INSTABILITY AND CAPE
WITH WAVE TO LIKELY KEEP STORMS GOING AND COULD REMAIN STRONG
LATER TONIGHT INTO EARLY FRIDAY. TIMING/COVERAGE SOMEWHAT UNCERTAIN BUT
TRENDS ARE IMPACTS IN OUR FA NEAR OR AFT MIDNIGHT. WITH SOME
UNCERTAINTY DID NOT INCREASE POPS AT THIS POINT. HIGH RES RAPID
REFRESH MODEL INDICATING POTENTIAL OF SOME STRONGER WINDS WITH
POSSIBLE BOWING COMPLEX REACHING CENTRAL DAKOTAS AROUND 06Z ALONG
COLD FRONT. SLIGHT RISK AREA HAS BEEN PUSHED FAR EAST AS THE
VALLEY SO STORMS WILL NEED TO BE MONITORED LATE TONIGHT.

FRONT WILL PUSH AS FAR EAST AS THE VALLEY ON FRIDAY MID DAY WITH
MAIN PCPN THREAT LINGERING IN THE AM. HOW FAR EAST WILL DETERMINE
WHERE STORMS AGAIN COULD INITIATE IN THE AFTERNOON. FAR EASTERN
COULD BE ON THE EDGE FOR STORM DEVELOPMENT. COLD ADVECTION NOT
SIGNIFICANT AND SURFACE WESTERLY FLOW SHOULD ALLOW TEMPERATURES TO
RECOVER CLOSE TO AVERAGE.

LOOKS QUIET FRIDAY NIGHT WITH FA IN BETWEEN FRONTAL PASSAGES.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 315 PM CDT THU JUL 24 2014

NEXT STRONGER COLD FRONT TO DROP THROUGH FA SATURDAY AS UPPER LOW
SAGS INTO THE NORTHERN FA. AIR MASS MORE STABLE WITH THIS BOUNDARY
SO THUNDERSTORMS LESS OF A THREAT. BEST CHANCE FOR SHOWERS WILL BE
ACROSS THE NORTH AS COLD POOL DESCENDS SOUTHWARD. WITH TIMING OF
THE FRONT SE HALF OF THE FA COULD STILL SEE MAXIMUM TEMPERATURES
CLOSE TO AVERAGE.

SECONDARY COLD FRONT DROPS THROUGH FA WHICH WILL KEEP TEMPERATURES
WELL BLO AVERAGE WITH SOME SPOTTY SHRA ALONG FRONT.

MONDAY TO THURSDAY...MODELS IN EXCELLENT AGREEMENT WITH 500MB NW
FLOW ALOFT AS WESTERN US UNDER RIDGE AND EASTERN US UNDER THE
TROUGH. THAT GIVES THE NORTHERN PLAINS SFC HIGH PRESSURE WITH
PREDOMINANTLY DRY WEATHER. TEMPS WILL TREND FROM JUST BELOW NORMAL
TO NORMAL...WITH HIGHS IN THE UPPER 70S TO LOW 80S. KEPT THE ISO
POCKETS OF SLIGHT CHC FOR THUNDER WED AND THU AS RIDGE ATTEMPTS TO
PUSH EAST AND HERE MAYBE A POSSIBILITY OF A WAVE ABLE TO RIDE RIDGE
AND BRING PCPN TO THE FA.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1153 PM CDT THU JUL 24 2014

FOG LOOP INDICATED PLENTY OF BLOW OFF MOVING INTO THE AREA FROM THE
WEST. ALSO LOWER CLOUDS HAVE DEVELOPED MAINLY OVER NORTHEASTERN ND.
CIGS WERE 3 TO 4 THOUSAND FT. EXPECT CLOUDS TO LOWER NORTH OF
DEVELOPING PRECIP AREA FROM FAR TO JMS. SOME MVFR CIGS POSSIBLE
NORTH OF THE LINE OF PRECIP OR THE NORTHERN TWO THIRDS OF THE AREA
OVERNIGHT.


&&

.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&

$$

UPDATE...HOPPES
SHORT TERM...VOELKER
LONG TERM...JK/VOELKER
AVIATION...HOPPES



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