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000
FXUS63 KFGF 160232
AFDFGF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND FORKS ND
932 PM CDT WED MAY 15 2013

.UPDATE...
ISSUED AT 932 PM CDT WED MAY 15 2013

DIURNAL CU HAS STARTED TO FADE AWAY AND SPRINKLES HAVE
DISSIPATED. GOING FORECAST HAD THE SPRINKLES ENDING AND CLOUDS
DECREASING FOR THE REST OF THE EVENING AND SEE LITTLE REASON TO
CHANGE THIS. TEMPS HAVE BEEN DROPPING A BIT FASTER THAN HOURLIES
SO TWEAKED LOWS DOWN A DEGREE OR TWO.

UPDATE ISSUED AT 628 PM CDT WED MAY 15 2013

MADE A FEW TWEAKS TO CLOUDS...BUT NO MAJOR CHANGES. RADAR SEEMS TO
BE ON A DOWNWARD TREND BUT THERE COULD STILL BE A FEW SPRINKLES
REACHING THE GROUND SO WILL KEEP THE MENTION WE HAVE GOING UNTIL
02Z OR SO. TEMPS CONTINUE TO SEEM ON TRACK TO BOTTOM OUT IN THE
UPPER 40S TO LOW 50S.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 320 PM CDT WED MAY 15 2013

THE MAIN CHALLENGE THIS AFTERNOON WILL BE UPCOMING VERY ACTIVE
WEATHER PATTERN LATER THIS WEEK INTO NEXT WEEK. MODELS ARE IN DECENT
AGREEMENT WITH THE OVERALL PATTERN...WITH SOME TIMING/PLACEMENT
DIFFERENCES WITH EVENTUAL LOCATION OF CLOSED UPPER LOW EARLY NEXT
WEEK.

FOR TONIGHT...EXPECT A DRY NIGHT WITH WEAK HIGH PRESSURE MOVING INTO
SW ONTARIO. TEMPS SHOULD FALL TO AROUND NORMAL FOR MID MAY WITH
LIGHT WINDS.

ON THURSDAY...MOISTURE WILL BEGIN INCREASING IN THE SOUTH WITH PWATS
AROUND AN INCH HERE BY LATE IN THE DAY. CAN/T RULE OUT A FEW SHOWERS
DURING THE AFTERNOON HERE...OTHERWISE IT SHOULD REMAIN DRY FOR MOST
AREAS.

FOR THURSDAY NIGHT...THERE WILL BE A THUNDERSTORM COMPLEX MOVING
CLOSE TO THE FAR SOUTHERN FORECAST AREA OVERNIGHT. FOR OUR
REGION...EXPECT INCREASING CHANCES FOR MAINLY SHOWERS AS PWATS RISE
OVER 1 INCH WITH MID LEVEL WAA/MOIST ADVECTION. NOT EXPECTING MUCH
IN THE WAY OF THUNDER...SO FOR NOW WILL LEAVE ALL PRECIP AS
SHOWERS.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 320 PM CDT WED MAY 15 2013

FOR FRIDAY/FRIDAY NIGHT...THE MOIST ADVECTION CONTINUES AS THE SW
FLOW ALOFT BECOMES MORE ESTABLISHED OVER THE EASTERN SLOPES OF THE
ROCKIES. THIS WILL MEAN MORE CHANCES FOR SHOWERS AND SOME ISOLATED
THUNDER WITH DAYTIME HIGHS HINGING ON JUST HOW MUCH INSOLATION WE
RECEIVE.

ON SATURDAY...DEEP MOISTURE WILL MOVE OVER THE REGION BY
AFTERNOON/EVENING WITH PWATS AROUND OR SLIGHTLY HIGHER THAN 1.50
INCHES. THIS COUPLED WITH FAIRLY HIGH CAPES PROGGED NEAR 3000 J/KG
IN THE SOUTH WITH A STRONG SFC WARM FRONT SHOULD PROVIDE THE FOCUS
FOR THUNDERSTORMS. GIVEN THE HIGH INSTABILITY AND MODEST DEEP
LAYERED SHEAR AROUND 40KT...SEVERE STORMS CAN/T BE RULED OUT AND OUR
FAR SOUTH COULD BE CLOSE TO A POTENTIAL LARGER SEVERE WEATHER EVENT
THAT SHOULD UNFOLD OVER SD. IT WILL ALSO GET MUGGY ON SAT WITH SFC
TDS PROGGED INTO THE MID 60S IN THE SOUTH AND NEAR 60 EVEN INTO THE
NORTHERN VALLEY. THE NAM IS FARTHER NORTH WITH POTENTIAL SEVERE
WEATHER THAN THE GFS...BUT ALL AREAS WILL SEE INCREASING CHANCES FOR
SHOWERS AND STORMS BY AFTERNOON WITH LOCALLY HEAVY RAIN ALSO
POSSIBLE.

FOR SATURDAY NIGHT THROUGH WEDNESDAY...THE 12 UTC GFS/ECMWF 500
HPA HEIGHT PATTERN IN GOOD AGREEMENT. ECMWF WAS MORE PROGRESSIVE
YESTERDAY WITH BROAD OPEN PACIFIC WAVE MOVING INTO AND THROUGH
NORTHERN PLAINS...NOW IT IS SIDING WITH ITS NEIGHBORING MODELS IN
A STACKED LOW SOLUTION SITUATED SOMEWHERE OVER THE NORTHERN PLAINS
MONDAY INTO TUESDAY. THE LATTER HALF OF THE WEEKEND WILL FEATURE
SHARP BOUNDARY OVER THE DAKOTAS WITH PERIODIC BOUTS OF HEALTHILY
NEGATIVE LI/SHOWALTERS LEADING TO A LENGTHY PERIOD OF LIKELY TRW
POPS. THIS REGIME IS CORROBORATED BY PRECIPITABLE WATER VALUES
FROM 1.0 TO 1.5 INCHES AND PERSISTENT ENHANCED MID-LEVEL
CONVERGENCE. RAW MODEL QPF SUGGESTS ANYWHERE FROM 1 TO 4 INCHES OF
RAIN THROUGH TUESDAY NIGHT REGION-WIDE. TEMPERATURES WILL FALL
BELOW NORMAL SUNDAY INTO EARLY NEXT WEEK WITH AFTERNOON HIGHS FROM
THE UPPER 50S TO MID 60S.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 628 PM CDT WED MAY 15 2013

VFR CONDITIONS WILL CONTINUE THROUGHOUT THE PERIOD WITH MAINLY MID
AND HIGH CLOUDS MOVING OVER THE AREA. WEST WINDS WILL BECOME LIGHT
AND VARIABLE THIS EVENING...THEN PICK UP OUT OF THE EAST TO AROUND
8 TO 10 KTS BY MID MORNING THURSDAY. A FEW SHOWERS OR EVEN
THUNDERSTORMS ARE POSSIBLE TOWARDS THE END OF THE PERIOD AROUND
KDVL...BUT THERE IS NOT ENOUGH CERTAINTY TO INCLUDE IN THE TAFS
QUITE YET.


&&

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

$$

UPDATE...JR
SHORT TERM...DK
LONG TERM...WJB/DK
AVIATION...JR