Area Forecast Discussion
Issued by NWS Grand Forks, ND

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FXUS63 KFGF 011519
AFDFGF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND FORKS ND
1019 AM CDT SAT AUG 1 2015

.UPDATE...
ISSUED AT 1019 AM CDT SAT AUG 1 2015

SATELLITE IMAGERY DEPICTS MID-LEVEL CU ASSOCIATED WITH AN AREA OF
FRONTOGENESIS...AND THERE ARE A COUPLE WEAK RADAR RETURNS.
INCLUDED ISOLD THUNDER FOR THIS FORCING AS IT PROPAGATES EASTWARD
INTO THE EARLY AFTERNOON HOURS WITH CAM GUIDANCE SUGGESTING
DEVELOPMENT (PLUS THERE IS ALREADY A COUPLE WEAK SHOWERS).

ATTENTION THEN TURNS TO THIS AFTERNOON AND POSSIBLE SEVERE STORMS.
WILL BE WATCHING LOW LEVEL MOISTURE ACROSS SE ND AND WC MN AHEAD
OF AN 850MB WIND SHIFT. CURRENT THINKING IS THAT WITH
EVAPOTRANSPIRATION COMBINED WITH WEAK MOISTURE
ADVECTION...DEWPOINT VALUES ACROSS THIS REGION SHOULD BE IN THE
LOW 60S...AND POSSIBLY MID 60S. THIS WOULD LEAD TO MLCAPE AT
LEAST 1500-2000 J/KG...AND COMBINED WITH 0-6KM SHEAR 35-40 KNOTS
THERE IS THE POTENTIAL FOR SEVERE STORMS. STILL SOME QUESTION
REGARDING WHEN STORMS WILL DEVELOP (WILL THEY DEVELOP ACROSS OUR
SOUTHERN FA...OR JUST TO THE SOUTH?)...WHICH IS DEPENDENT ON
CAPPING (WHICH IS DEPENDENT ON LOW LEVEL MOISTURE). STILL NOT
ENOUGH CONFIDENCE TO MENTION T+ IN THE GRIDS...WILL AWAIT THE NEXT
SPC DAY 1 OUTLOOK AND ADJUST FROM THERE.

AN AREA OF STORMS WILL AFFECT THE NORTHERN FA WITH THE PASSAGE OF
ANOTHER UPPER LEVEL WAVE TONIGHT. ALTHOUGH DEEP LAYER SHEAR WILL
BE VERY STRONG (60+ KNOTS)...INSTABILITY SHOULD BE VERY WEAK. WILL
NEED TO EVALUATE THIS ACTIVITY IN MORE DEPTH.

&&

.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 356 AM CDT SAT AUG 1 2015

NORTHWEST-SOUTHEAST ORIENTATED UPPER LEVEL JET ESSENTIALLY REMAINS
OVER THE NORTHEAST ZONES HOWEVER JET DOES OSCILLATE NORTHEAST OF THE
FORECAST AREA THEN BACK OVER THE NORTHEAST ZONES AS SHORT WAVES MOVE
THROUGH THE FLOW. UPPER LEVEL TROUGH OVER NORTHERN MAN WILL ROTATE
ACROSS ONTARIO SAT NIGHT ELSEWHERE WATER VAPOR LOOP INDICATED SHORT
WAVES OVER CENTRAL SASK AND ANOTHER OVER ALTA/BC BORDER. BC SHORT
WAVE WILL DROP SOUTH ACROSS THE GREAT LAKE STATES SUN AND AMPLIFY
THE UPPER TROUGH EAST OF THE AREA. RIDGE BUILDING COMMENCES IN THE
WESTERN US SUN AND SHIFTS INTO THE HIGH PLAINS BY 84 HOURS.

PRECIPITABLE WATER INCREASES OVER AN INCH IN THE SOUTH WITH SURFACE
TROUGH MOVING THROUGH. SHOWALTERS BECOME NEGATIVE OVER THE SOUTHERN
ZONES THIS AFTERNOON AND EVENING WITH LOW LEVEL MOISTURE. SHOWALTERS
ALSO BECOME NEGATIVE IN THE NORTH THIS AFTERNOON AND OVERNIGHT WITH
APPROACHING SHORT WAVE. PRECIPITABLE WATER ALSO INCREASES OVER AN
INCH FROM THE NORTH WITH TROUGH MOVING ACROSS SOUTHERN CANADA.

WEAK SURFACE LOW OVER THE WESTERN DAKOTAS WILL MOVE INTO MN AND
DISSIPATE THIS EVENING. ANOTHER SURFACE LOW OVER SOUTHERN ALTA WILL
MOVE INTO MN BY 12Z SUN. THEN HIGH PRESSURE FOLLOWS FOR THE REST OF
THE PERIOD.


.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 356 AM CDT SAT AUG 1 2015

FOR TUESDAY THROUGH FRIDAY...LONG RANGE GFS/ECMWF HAVE REMAINED IN
FAIR AGREEMENT IN SHOWING UPPER TROUGH OVER ONTARIO MOVING EAST AND
A WESTERLY FLOW AT 500 MB SETTING UP OVER THE NRN PLAINS/SRN CANADA
MID TO LATE WEEK.  WITH THIS WILL COME A COUPLE OF DISTURBANCES WITH
THUNDERSTORM CHANCES.   00Z ECMWF HAS A TAD WETTER PATTERN VS A BIT
DRIER 00Z GFS.  BLENDED MODEL SOLN HAVE POPS IN THE AREA WED-FRI AND
LEFT THEM FOR NOW.  THE MAIN UPPER HEAT RIDGE WILL REMAIN OVER THE
SRN PLAINS AND AREA WILL BE A TAD BELOW NORMAL TEMP REGIME THRU THE
PD.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 700 AM CDT SAT AUG 1 2015

FOG LOOP AND SURFACE OBS INDICATED TWO NORTHWEST-SOUTHEAST
ORIENTATED BANDS OF CLOUDS. CLOUD SHOULD MOVE EAST DURING THE DAY.
CIGS WEE HIGH AT OR ABOVE 10 THOUSAND FT. VFR CONDITIONS EXPECTED
TODAY.


&&

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

$$

UPDATE...TG
SHORT TERM...HOPPES
LONG TERM...RIDDLE
AVIATION...HOPPES



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