Area Forecast Discussion
Issued by NWS Grand Forks, ND

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000
FXUS63 KFGF 201202 AAA
AFDFGF

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE GRAND FORKS ND
702 AM CDT SUN JUL 20 2014

.UPDATE...
ISSUED AT 702 AM CDT SUN JUL 20 2014

LATEST RAP/HRRR NOW PUSHING SFC TROUGH TO THE EAST MORE QUICKLY
SO THAT BY THE TIME CONVECTION INITIATES FROM 20 TO 22 UTC...IT
IS MOSTLY EAST OF THE FORECAST AREA. WOULD LIKE TO SEE THIS TREND
CONTINUE BEFORE MAKING ADJUSTMENTS TO THE FORECAST. FOR NOW...WILL
NOT MAKE ANY CHANGES AND MONITOR SUBSEQUENT HIGH RESOLUTION MODEL
RUNS. REST OF FORECAST IN GOOD SHAPE WITH NO CHANGES AT THIS TIME.

&&

.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 338 AM CDT SUN JUL 20 2014

CHALLENGES INCLUDE THUNDERSTORM CHANCES AND SEVERE THREAT THIS
AFTERNOON/EVENING AND AGAIN MONDAY NIGHT. HIGH RESOLUTION/GLOBAL
MODELS IN GOOD AGREEMENT. WILL USE A RAP/HRRR BLEND THROUGH 00 UTC
TONIGHT AND A GLOBAL ENSEMBLE THEREAFTER.

FOR TODAY...SFC TROUGH CURRENTLY ACROSS THE WESTERN DAKOTAS WILL
MOVE EAST AND SET-UP ALONG A LINE FROM HALLOCK TO ABERDEEN BY 18
UTC. STRONG MOISTURE ADVECTION AND DIABATIC HEATING AHEAD OF THIS
BOUNDARY WILL RESULT IN AFTERNOON MUCAPE UP TO 3000 J/KG. PRIMARY
FORCING ALOFT REMAINS NORTH OF THE CANADIAN BORDER...BUT BULK
SHEAR UP TO 30 KTS STILL POSSIBLE. ADDED SEVERE MENTION ACROSS
PORTIONS OF NORTHWEST MN LATE AFTERNOON/EARLY EVENING TO THE WX
GRIDS TO COINCIDE WITH SPC SLIGHT RISK AREA. PRIMARY THREATS ARE
LARGE HAIL AND DAMAGING WIND. AREAS WEST OF THE SFC TROUGH WILL
REMAIN DRY THROUGH THE DAY.

IN ADDITION...TEMPS WILL SOAR INTO THE UPPER 80S TO LOWER 90S
TODAY. COMBINED WITH DEW POINTS RISING INTO THE LOWER 70S...HEAT
INDEX VALUES COULD FLIRT WITH THE UPPER 90S. NO PLANS FOR A HEAT
ADVISORY AS WORST CONDITIONS SHOULD REMAIN BELOW 100 DEGREES AND
BE SHORT-LIVED.

MONDAY WILL SEE A BATTLE BETWEEN SFC HIGH PRESSURE ACROSS THE
SOUTHERN CANADIAN PRAIRIES AND DEVELOPING LOW PRESSURE ACROSS SD
WITH A WELL-DEFINED FRONTAL BOUNDARY SOMEWHERE ACROSS THE SOUTHERN
FORECAST AREA. TEMPS SOUTH OF THIS BOUNDARY WILL RISE ONCE AGAIN
INTO THE LOWER 90S WITH POSSIBLE HEAT ADVISORY CONDITIONS
DEVELOPING BY MID-LATE AFTERNOON. FARTHER NORTH TEMPS WILL BE A
BIT COOLER...TOPPING OUT IN THE MID TO UPPER 80S. SOME AFTERNOON
CONVECTION IS POSSIBLE ACROSS THE CENTRAL AND NORTHERN FORECAST
AREA IN LESS CAPPED MID-LEVEL WARM AIR ADVECTION REGIME...BUT MOST
OF THE DAY SHOULD REMAIN DRY.

.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 338 AM CDT SUN JUL 20 2014

ATTENTION QUICKLY TURNS TO MONDAY NIGHT WHEN MOST MODELS ARE
HINTING AT SOME KIND OF CONVECTIVE COMPLEX ROLLING ACROSS THE
NORTHERN PLAINS. A HIGHLY UNSTABLE ENVIRONMENT WITH MLCAPE VALUES
UP TO 5000 J/KG WILL DEVELOP TO THE NORTH AND EAST OF THE SFC LOW.
INCREASING WESTERLIES ALOFT FROM AN APPROACHING 500 HPA WAVE WILL
HELP TRIGGER CONVECTIVE INITIATION. SHEAR PROFILES INITIALLY
SUPPORT SCATTERED MULTICELLS/SUPERCELLS...BUT SHOULD QUICKLY GROW
UPSCALE INTO A MCS WITH THE PRIMARY THREAT BEING DAMAGING WIND.
ADDED SEVERE MENTION TO THE WX GRIDS MONDAY NIGHT MAINLY ALONG AND
SOUTH OF THE I-94/HWY 10 CORRIDOR.

TUESDAY WILL BE DRIER AND COOLER WITH SFC HIGH PRESSURE BUILDING
ACROSS THE REGION. TEMPS WILL TOP OUT IN THE MID 70S TO LOWER 80S.

WEDNESDAY-SATURDAY...UPPER RIDGING ACROSS THE ROCKY MOUNTAINS
WILL EVENTUALLY BE KNOCKED DOWN BY A STRONG UPPER LOW BY LATER IN
THE WEEK. THE DETAILS REGARDING THE EXACT TRACK/SPEED OF THIS
UPPER LOW ARE STILL UNCERTAIN...BUT THE GENERAL IDEA IS THAT THE
PERIOD WILL START OFF DRY...WITH THUNDER CHANCES INCREASING BY
LATER ON THURSDAY OR FRIDAY. TEMPERATURES WILL BE NEAR NORMAL
VALUES...WITH EXACT VALUES DEPENDENT ON THE LOCATION OF THE UPPER
LOW.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 702 AM CDT SUN JUL 20 2014

EXPECT VFR CONDITIONS TO PERSIST AT ALL TAF AIRFIELDS THROUGH 12
UTC MONDAY. DID ADD VCTS AT KBJI BETWEEN 00 AND 04 UTC...BUT
TIMING AND LOCATION OF CONVECTION STILL TOO UNCERTAIN TO INCLUDE
PREDOMINANT THUNDER. SOUTHERLY WINDS...GUSTING AT TIMES TO 20
KTS...WILL SHIFT TO THE WEST-SOUTHWEST AS SFC TROUGH MOVES ACROSS
THE REGION. WINDS TO BECOME LIGHT AND VARIABLE OVERNIGHT WITH
BUILDING HIGH PRESSURE.

&&

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

$$

UPDATE...ROGERS
SHORT TERM...ROGERS
LONG TERM...ROGERS/TG
AVIATION...ROGERS





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