000
FXUS63 KFGF 162346
AFDFGF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND FORKS ND
646 PM CDT THU MAY 16 2013

.UPDATE...
ISSUED AT 646 PM CDT THU MAY 16 2013

BAND OF LIGHT RAIN CONTINUES FROM NEAR DEVILS LAKE TO THE CENTRAL
RED RIVER VALLEY INTO NORTHWESTERN MINNESOTA...WITH SPRINKLES
ELSEWHERE. THE NAM AND RAP ARE IN PRETTY GOOD AGREEMENT ON THIS
ACTIVITY DIMINISHING LATER THIS EVENING AS THE COMPLEX OVER SD/MN
GETS GOING AND ROBS MOISTURE. KEPT HIGH POPS IN THE NORTH THIS
EVENING BEFORE TRANSITIONING TO BETTER PERCENTAGES IN THE SOUTH
LATER ON TONIGHT. LOWERED TEMPS A BIT IN THE NORTHWEST AS READINGS
HAVE ALREADY DROPPED INTO THE LOWER 50S AND THERE COULD BE SOME
BREAKS IN THE CLOUDS LATER TONIGHT TO ALLOW IT TO GET DOWN INTO
THE UPPER 40S.

&&

.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 120 PM CDT THU MAY 16 2013

THE MAIN CHALLENGE WILL BE UPCOMING PROLONGED WET PATTERN TONIGHT
INTO THE MIDDLE OF NEXT WEEK. MODELS ARE IN GOOD OVERALL AGREEMENT
INITIALLY...WITH SOME DIFFERENCES BY NEXT WEEK. THE NAM/GFS ARE A
GOOD COMPROMISE IN THE NEAR TERM.

FOR TONIGHT...THERE WILL BE AN AREA OF SHOWERS MOVING FROM WEST TO
EAST ACROSS THE AREA. THIS BAND OF SHOWERS IS BEING AIDED BY
STRONG MID LEVEL OMEGA AND UPPER LEVEL DIVERGENCE...AS PWATS
INCREASE TO AROUND 1 INCH. THERE SHOULD BE A BAND OF STRONGER
CONVECTION SOUTH OF THE AREA OVERNIGHT...THAT SHOULD ROB THE
DEEPER MOISTURE FROM OUR AREA. WE WILL INCREASE POPS THIS EVENING
IN THE WEST INTO THE CENTRAL RED RIVER VALLEY WITH STRONGER ECHOES
MOVING INTO THE AREA.

FOR FRIDAY...WE SHOULD GET A BREAK IN THE LARGER SCALE SHOWERS
WITH EASTERLY FLOW NEAR THE SFC INCREASING. WE WILL MAINTAIN A LOW
CHANCE FOR SHOWERS THOUGH WITH PLENTY OF CLOUDS AND POSSIBLY A
SUBTLE SHORTWAVE MOVING THROUGH.

FOR FRIDAY NIGHT...A LLJ WILL DEVELOP IN SD AND MOVE INTO THE
SOUTH OVERNIGHT EXPECT AN AREA OF SHOWERS AND THUNDERSTORMS TO
MOVE INTO THE AREA...WITH THE BEST CHANCE FOR THUNDER IN THE
SOUTH. THERE WILL BE SOME ELEVATED INSTABILITY WITH 850MB CAPE
AROUND 1000 J/KG...SO A STRONG TO LOCALLY SEVERE STORM IS POSSIBLE.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 310 PM CDT THU MAY 16 2013

FOR SATURDAY THROUGH SUNDAY...A VERY ACTIVE WEATHER PATTERN IS
EXPECTED. SHOWERS AND STORMS SHOULD BE ONGOING AT LEAST IN THE
SOUTH SATURDAY MORNING. BY SATURDAY AFTERNOON AND EVENING...DEEP
MOISTURE AND STRONG INSTABILITY SHOULD DEVELOP OVER SE ND...NEAR
THE EDGE OF A STRONG CAPPING INVERSION. MLCAPES ARE PROGGED OVER
4000 J/KG INTO NC SD...AND AROUND 3000 J/KG IN SE ND. EXPECT
STORMS TO DEVELOP QUICKLY IN SD ONCE THE CAP BREAKS...AND MOVE
NORTH AND EAST INTO THE AREA SATURDAY NIGHT AND SUNDAY. SOME
STORMS COULD BE SEVERE SATURDAY NIGHT INTO SUNDAY...BUT LOCALLY
HEAVY RAIN IS POSSIBLE WITH PWATS RISING TO AROUND 1.5 INCHES OR
EVEN A BIT HIGHER. WE HAVE ISSUED AN ESF FOR SOME LOCALIZED
FLOODING POSSIBLE IF TRAINING ECHOES OCCUR WITH A PARALLEL UPPER
BOUNDARY.

SAME SCENARIO IN PLACE FOR EXTENDED...AFTER A WEEKEND OF RAIN AND
THUNDERSTORMS...UPPER LOW LIKELY TO BE LOCATED OVER AN AREA ANYWHERE
FROM SOUTHEAST NORTH DAKOTA TO IOWA. MOISTURE WILL STILL BE
TRANSPORTED CYCLONICALLY AROUND THIS STACKED SYSTEM CONTINUING
SHOWERS WITH THE POSSIBILITY OF SOME THUNDER. ORIENTATION OF
BOUNDARY AND ASSOCIATED CONVECTIVE PARAMETERS MAKE MONDAY THE MORE
LIKELY TIME FOR THUNDER ACTIVITY...LESS SO ON TUESDAY AND BY
WEDNESDAY PRECIPITATION SHOULD BE MORE SHOWERY OR EVEN JUST SOME
STRATIFORM RAIN. GOING POP FREE FINALLY BY THURSDAY AS AN OMEGA
BLOCK DEVELOPS WITH NORTHERN PLAINS UNDER THE RIDGE PART OF THE
BLOCK.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 646 PM CDT THU MAY 16 2013

VFR CEILINGS AND LIGHT RAIN OVER THE NORTHERN TAF SITES WILL
CONTINUE THROUGH THE EVENING HOURS. WILL HAVE TO WATCH FOR SOME
MVFR CLOUDS COMING IN LATER TONIGHT AND INTO TOMORROW BUT FOR NOW
KEPT MVFR MENTION JUST AT KDVL. RAIN HAS BEEN PLAYING HAVOC ON THE
WINDS WITH KFAR BEING QUITE BREEZY FROM THE NORTH. THINK THAT
THINGS SHOULD CALM DOWN AND GO BACK TO THE GRADIENT EASTERLIES
LATER ON THIS EVENING.

&&

.HYDROLOGY...
ISSUED AT 310 PM CDT THU MAY 16 2013

THE NORTHERN PORTION OF THE RED RIVER CONTINUES TO SEE RIVER LEVELS
UNDERGO RECESSION AT DRAYTON AND PEMBINA. THIS IS THE LAST REMNANT
OF THE SNOWMELT WATER SURGE CONTINUING TO MOVE NORTHWARD INTO
CANADA.

A PROLONGED PERIOD OF UNSETTLED WEATHER IS EXPECTED TO BEGIN THIS
EVENING AND CONTINUE THROUGH TUESDAY. CUMULATIVE RAINFALL TOTALS OF
2 TO 4 INCHES ACROSS THE RED RIVER BASIN...WITH LOCALLY HIGHER
AMOUNTS...WILL BE POSSIBLE BY TUESDAY MORNING. LOCALIZED FLASH
FLOODING IS A POSSIBILITY OVER THE WEEKEND DUE TO TRAINING
THUNDERSTORMS. IN ADDITION...DESPITE SOME RAINFALL INFILTRATION
DUE TO PATCHY DRY TOPSOIL...ENOUGH RUNOFF MAY OCCUR TO CAUSE SOME
SMALLER TRIBUTARIES TO RISE BACK ABOVE FLOOD STAGE NEXT WEEK. AS A
RESULT...A HYDROLOGIC OUTLOOK HAS BEEN ISSUED TO HIGHLIGHT THE
SITUATION.

&&

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

$$

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