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000
FXUS63 KFGF 181157
AFDFGF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND FORKS ND
657 AM CDT SAT MAY 18 2013

.UPDATE...
ISSUED AT 650 AM CDT SAT MAY 18 2013

BAND OF MAINLY SHRA SLOWLY LIFTING NORTH. ADJUSTED POPS BASED ON
SLOWER MOVEMENT AND WENT PRIMARILY SHRA WITH MAYBE SOME ISOLD T.
MAINTAINED CHANCE POPS THIS AFTERNOON BUT CAPPING MAY LIMIT
CONVECTIVE DEVELOPMENT UNTIL LATE AFTERNOON. KEEPING TEMPERATURES
AS IS FOR NOW.

&&

.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 326 AM CDT SAT MAY 18 2013

FORECAST CHALLENGE THROUGH THE SHORT TERM WILL CONTINUE TO BE PCPN
CHANCES AS WELL AS SEVERE STORM AND HEAVY RAIN POTENTIAL. MODELS
IN FAIR AGREEMENT WITH MAIN FEATURES HOWEVER SUBTLE DIFFERENCES
EXIST WITH SURFACE LOW/BOUNDARY POSITIONS TODAY.

ARC OF WEAKENING CONVECTION LIFTING NE THROUGH FA AT 30KTS WILL
CONTINUE TO PROPAGATE NE THROUGH THE MORNING AND INTO EARLY
AFTERNOON. WILL ATTEMPT TO ADJUST/TIME POPS ACCORDINGLY.

TEMPERATURES WILL BE TRICKY AND DEPENDENT ON DEGREE OF CLOUD COVER
AND HOW FAR NORTH WARM FRONT GETS. WITH WARM COLUMN ANY BREAKS
WILL REALLY BOOST TEMPERATURES.

LATER TODAY AND INTO TONIGHT. SURFACE INVERTED TROUGH TO SHARPEN
ACROSS FA PROVIDING GOOD SOURCE OF LOW LEVEL CONVERGENCE. TOUGH TO
DETERMINE ANY SPECIFIC SHORT WAVE HOWEVER REGION COMES UNDER
ENTRANCE REGION OF MODEST JET STREAK WHICH WILL AID IN UPPER
SUPPORT. MODELS DIFFER ON LOCATION OF SURFACE LOW WHICH WILL RIDE
NORTHWARD ALONG TROUGH AS WELL AS POSITION OF WARM FRONTAL
BOUNDARY. MODELS INDICATING GOOD SURFACE MOISTURE FLUX WITH 60
DEWPOINTS SPREADING NORTHWARD THROUGH MOST OF FA. PRECIPITABLE H2O
VALUES INCREASE TO AROUND 1.5 BY EVENING. GREATEST INSTABILITY AND
CAPE ACROSS SOUTH HALF OF FA AND LOOKS TO BE THE FAVORED LOCATION
FOR SEVERE POTENTIAL. SOME CAPPING MAY INITIALLY DELAY CONVECTIVE
INITIATION DURING THE AFTERNOON. HEAVY RAIN POTENTIAL THERE BUT WITH
DIFFERENCES IN SURFACE LOW POSITION TO ENHANCE LOW LEVEL
CONVERGENCE NOT AS CLEAR CUT.

INVERTED TROUGH TO DRIFT EAST SUNDAY WHICH WILL PUT HEAVIER RAIN
THREAT INTO MN. TEMPERATURES TO BE QUITE A BIT COOLER ON BACK SIDE
OF INVERTED TROUGH.

.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 326 AM CDT SAT MAY 18 2013

CUT OFF LOW TAKES OVER AND DRIFTS ACROSS E SD INTO S MN TO START WORK
WEEK FOR CONTINUED MODERATE RAIN POTENTIAL AND COOLER TEMPERATURES.

TUESDAY-FRIDAY...THE UPPER LOW WILL SLOWLY SHIFT EASTWARD FROM THE
CENTRAL/NORTHERN PLAINS INTO THE GREAT LAKES DURING THIS PERIOD. THE
00Z GFS/12Z ECMWF BEGIN TO SHIFT SHOWER ACTIVITY SOUTH AND EAST ON
WEDNESDAY...WITH THE GEM SLOWER IN ENDING THE PRECIP. WILL CONTINUE
TO MENTION POPS ACROSS THE SOUTHEAST THROUGH WEDNESDAY NIGHT. SFC
HIGH PRESSURE IS EXPECTED TO BUILD ACROSS THE AREA TOWARDS THE END
OF THE WEEK AS MID/UPPER LEVEL RIDGING DEVELOPS ACROSS THE PLAINS.
BELOW NORMAL TEMPS WILL MODERATE BACK TO NEAR NORMAL BY LATE NEXT
WEEK.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 650 AM CDT SAT MAY 18 2013

WITH SHOWERS IN THE VCNTY CIGS VARY GREATLY. CIGS GENERALLY BOUNCING
BETWEEN MVFR/VFR WITH MOSTLY VFR CIGS. THERE IS HOWEVER SOME
LOCALIZED IFR CIGS IN BR BUT NOT LIMITED TO WITHIN RAIN BAND.
EXPECT CONDITION TO PERSIST THROUGH THE MORNING AS SHRA LIFT
NORTHWARD. COULD SEE MORE VFR CONDITIONS THIS AFTERNOON WITH TSRA
POSSIBLE LATE AFTERNOON.

&&

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

$$

UPDATE...VOELKER
SHORT TERM...VOELKER
LONG TERM...MAKOWSKI/VOELKER
AVIATION...VOELKER