Area Forecast Discussion
Issued by NWS Grand Forks, ND

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FXUS63 KFGF 121813
AFDFGF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND FORKS ND
113 PM CDT SAT JUL 12 2014

.UPDATE...
ISSUED AT 112 PM CDT SAT JUL 12 2014

CONVECTION FORMING ACROSS MANITOBA IS FORECAST TO REACH THE
INTERNATIONAL BORDER REGION IN THE 21Z - 23Z TIME FRAME. HRRR
SUGGESTS 40KTS TO 45 KTS ALONG BOUNDARY WITH TSRA. WILL INTRODUCE
RISK +TSRA INTO EARLY EVENING OVER FAR NORTH/EAST CWFA. OTRW FCST
SEEMS ON TRACK.

UPDATE ISSUED AT 1009 AM CDT SAT JUL 12 2014

MADE A FEW MINOR TWEAKS TO CLOUDS AND POPS BASED ON TRENDS BUT THE
INHERITED FORECAST IS ON TRACK.

&&

.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 339 AM CDT SAT JUL 12 2014

500 MB RIDGE BUILDING INTO BRITISH COLUMBIA THIS MORNING WITH
ANOTHER CENTER OF UPPER LEVEL HIGH PRESSURE SYSTEM OVER OKLAHOMA.
CIRCULATION AROUND THIS OKLAHOMA UPPER HIGH IS SENDING MOISTURE
FROM NORTHWEST MEXICO INTO THE DESERT SOUTHWEST WITH SOME MOISTURE
MAKING THE TREK NORTH INTO IDAHO/WYOMING AND THEN EAST THROUGH THE
CENTRAL PLAINS. FAR SRN ND ON NORTHERN EDGE OF THIS MID LEVEL
MOISTURE ZONE TODAY AND DESPITE VERY WEAK INSTABILITY A FEW
SHOWERS OR THUNDERSTORMS PSBL ALONG THE SD BORDER AS A COUPLE OF
WEAK IMPLUSES MOVE FROM SE MONTANA AND THRU NRN SD.

OF MORE PRESSING CONCERN IS UPPER LOW IN NORTHWEST MANITOBA. A
STRONG SHORT WAVE MOVING ON THE NE SIDE OF THE UPPER CURRENTLY
WITH ANOTHER ONE DROPPING SOUTHEAST THRU NRN SASK. THIS ENTIRE
UPPER LOW WILL DROP SOUTH TODAY WITH LEADING SHORT WAVE IN NRN
SASK DROPPING SOUTHEAST ACCOMPANIED BY A SURFACE COLD FRONT. THIS
COLD FRONT WILL BE MOVING INTO SOUTHERN MANITOBA MID AFTN AND TO
ALONG THE MB/ND BORDER REGION 4-6 PM AND THEN SOUTHWARD THRU ERN
ND/NW MN THIS EVE. ENOUGH HEATING TODAY EXPECTED AHEAD OF FRONT TO
GENERATE AROUND 1000 J/KG CAPE DESPITE DEW PTS IN THE MID TO UPPER
50S. LOWERING FREEZING LEVELS AS WELL WITH COOLER AIR ALOFT ALONG
FRONT WILL MEAN BETTER CHC OF STORMS THAT COULD PRODUCE MARGINALLY
SEVERE HAIL. ALSO PRETTY DRY SUB 700 MB LAYER SO COULD BE GUSTY
WINDS MIXING DOWN TO THE SFC. PER SPC DISCUSSION...MOST PRONE AREA
WILL BE SOUTHERN MANITOBA WHERE STORMS WILL INTENSITY AT MAX
HEATING AND THEN MOVE INTO FAR NRN ND/FAR NW MN. BY THE TIME THE
FRONT AND STORMS REACH THIEF RIVER FALLS-GRAND FORKS-DEVILS LAKE
REGION 00-02Z INSTABILITY WILL BE DECREASING AND WILL START TO
SEE DIMINISHING ACTIVITY. TSTM CHANCES REALLY LOWERS BY 06Z AS
INSTABILITY DIMINISHES AS FRONT PUSHES THRU FARGO-PARK RAPIDS
AREA. 00Z SPC WRF SHOWED THE ABOVE SCENERIO QUITE WELL.

CLEARING BEHIND THE FRONT WILL NOT LAST TOO LONG AS UPPER LOW
MOVES TOWARD NRN MN BY 12Z MON. EXPECT CLOUDS TO MOVE BACK
SOUTHWARD COVERAGE NE 1/2 OF FCST AREA WITH CHC OF SHOWERS MAINLY
IN THE AFTN.

.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 339 AM CDT SAT JUL 12 2014

CHC OF SHOWERS WILL CONTINUE ESP FAR NE ND/NRN MN SUN
NIGHT INTO MONDAY AS UPPER LOW CONTINUES TO DROP SOUTH AND THEN
SOUTHEAST.  CLEARING MONDAY NIGHT AS HIGH PRESSURE BUILDS IN.
MONDAY WIL BE A CHILLY DAY WITH RECORD LOW MAX TEMPS PSBL IN GRAND
FORKS AND FARGO WHERE FCST HIGHS AROUND 62-63 MATCH CURRENT RECORD
LOW MAXES WHICH WERE ESTABLISHED FOR JULY 13 IN 1993.

FOR TUESDAY THROUGH FRIDAY...LONG WAVE PATTERN DEAMPLIFIES THIS PERIOD.
LONG WAVE TROUGH OVER THE GULF OF AK RETROGRADES AND WEAKENS A BIT
WHILE LONG WAVE RIDGE OVER WESTERN NORTH AMERICA GETS FLATTENED.
PATTERN BECOMES MOSTLY ZONAL BY THE END OF THE PERIOD. FLOW
BECOMES SPLIT BY THE END OF THE PERIOD WITH NORTHERN STREAM OVER
NORTHERN CANADA AND SOUTHERN STREAM ALONG THE NORTHERN STATES. THE
GFS IS THE FASTER SOLUTION AT THE BEGINNING OF THE PERIOD THAN THE
ECMWF AND THE ECMWF BECOMES THE FASTER SOLUTION BY THE END OF THE
PERIOD IN THE SOUTHERN STREAM. GFS AND ECMWF HAVE BEEN TRENDING
FASTER AND FARTHER SOUTH WITH SOLUTIONS OVER THE LAST COUPLE RUNS.
WILL BLEND THE ECMWF AND GFS.

WILL EXPAND POPS A LITTLE FARTHER SOUTH THU NIGHT AND FRI. WILL TRIM
BACK POPS FRI NIGHT IN THE WESTERN ZONES.

LITTLE CHANGE TO TEMPS. A DEGREE HIGHER FOR TUE AND WED. NO CHANGE

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1221 PM CDT SAT JUL 12 2014

SOUTHWEST TO WEST WINDS WILL BECOME GUSTY BY MID AFTERNOON AS COLD
FRONT HEADS TOWARD THE INTERNATIONAL BORDER.  VFR CU DECK WILL BUILD
WITH CHC TSTMS FROM KDVL-VALLEY-KBJI PRIOR TO SUNSET ALONG FRONTAL
BOUNDARY.  WINDS WILL THEN SHIFT TO NORTHWEST...INCREASING ONCE MORE
BY LATE MORNING SUNDAY.  WINDOW OF OPPORTUNITY FOR STORMS APPEARS TO
BE ABOUT 4 HOURS WIDE WITH BEST CHANCES VCNTY KGFK-KTVF.

&&

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

$$

UPDATE...EWENS
SHORT TERM...RIDDLE
LONG TERM...HOPPES/RIDDLE
AVIATION...WJB





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