Area Forecast Discussion
Issued by NWS Twin Cities, MN

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000
FXUS63 KMPX 022011
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1258 PM CDT TUE JUN 2 2015

.UPDATE...FOR 18Z AVIATION DISCUSSION BELOW

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 355 AM CDT TUE JUN 2 2015

CLUSTERS OF THUNDERSTORMS ACROSS NORTH DAKOTA AND NEBRASKA WILL
WEAKEN THIS MORNING WITH THE LLJ. THE NORTH DAKOTA CLUSTER MAY
MORPH MORE INTO A STRATIFORM RAIN BAND AS IT BUILDS EASTWARD INTO
NORTHERN MINNESOTA. NONE OF THIS ACTIVITY IS EXPECTED TO IMPACT
THE CWA SIGNIFICANTLY...ALTHOUGH A FEW SHOWERS COULD FROM OVER
WRN MN TODAY AS THE VORT PASSES TO THE NORTH. RATHER...
REDEVELOPMENT THIS AFTERNOON ACROSS THE NORTHERN PLAINS WILL
DETERMINE OUR CHANCES FOR SIGNIFICANT PRECIPITATION DURING THE
SHORT TERM PERIOD. THE MAIN PROBLEM TONIGHT IS WEAK FORCING. OUR
CHANCE FOR RAIN TONIGHT WILL BE LARGELY GOVERNED BY 1) CONVECTIVE
REDEVELOPMENT THIS AFTERNOON OVER THE PLAINS...AND 2) HOW IT CAN
MAINTAIN ITSELF THROUGH TONIGHT. ANY SCATTERED ACTIVITY THIS
AFTERNOON AND EVENING COULD BECOME FORWARD PROPAGATING WEAK MCS/S
TONIGHT...MAINTAINED BY A STRENGTHENING LLJ AND INCREASING
ELEVATED INSTABILITY. NOT PARTICULARLY CONFIDENT HOW WIDESPREAD
THIS WILL BE OR WHERE EACH MCS WILL TRACK...AS SEEMINGLY EVERY
MODEL HAS A UNIQUE SOLUTION. FURTHER...ANY DEVELOPMENT WILL
DEPEND ON A NUMBER OF FACTORS NOT YET RESOLVED. THEREFORE...FORECAST
MODIFICATIONS ARE LIKELY TODAY WHEN TRENDS BECOME BETTER APPARENT.

CONVECTIVE CLOUD DEBRIS OVERHEAD WILL SCATTER OUT THIS MORNING
FOLLOWING THE DECAY OF ONGOING MCS/S. SHOULD SEE A FAIR AMOUNT OF
SUN BY MID MORNING WITH SOUTH WINDS BECOMING GUSTY. HIGHS WILL
LIKELY TOP OFF IN THE MID TO UPPER 70S...WITH AN 80 OR TWO
POSSIBLE IN THE MN RIVER VALLEY.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 355 AM CDT TUE JUN 2 2015

THROUGH THE LONG TERM...WITH RESPECT TO PRECIP...MODEL SPREAD IS
ABOVE NORMAL THROUGH THE WHOLE PERIOD...WHICH MEANS CONFIDENCE IN
THE PRECIP FORECAST IS BELOW NORMAL. IT STARTS RIGHT OUT THE GATE
WITH A FAIR AMOUNT OF SPREAD ON HOW MUCH SHOWER/THUNDERSTORM
ACTIVITY WE WILL HAVE TONIGHT BLEEDING INTO WEDNESDAY
MORNING...THERE REMAINS A HIGH DEGREE OF UNCERTAINTY ON HOW MUCH
REDEVELOPMENT WE WILL SEE ALONG THE FRONT WEDNESDAY AFTERNOON INTO
THE EVENING...A LOT OF SPREAD WITH HOW FAR NORTH ACTIVITY WILL BE
THURSDAY INTO FRIDAY...AND THERE IS A GOOD DEAL OF SPREAD WITH HOW
STRONG THE SYSTEM OVER THE WEEKEND WILL BE.

WHAT WE DO KNOW IS WE WILL BE STARTING OFF WEDNESDAY MORNING WITH A
FRONT/SFC TROUGH FROM THE MADISON/CANBY AREA UP TOWARD INTERNATIONAL
FALLS. THE LLJ AHEAD OF THE FRONT WILL BE A SHELL OF WHAT IT
WILL HAVE BEEN AS IT ENTERS WRN MN THIS AFTERNOON...BUT SHOULD BE
STRONG ENOUGH TO SUPPORT FAIRLY WIDESPREAD SHOWER/THUNDERSTORM
ACTIVITY WEDNESDAY MORNING FROM SOUTH CENTRAL MN TOWARD WRN LAKE
SUPERIOR. IN ALL LIKELIHOOD...WE WILL SEE A LULL IN ACTIVITY FROM
THE LATE MORNING INTO THE EARLY AFTERNOON AS THE ATMO TRIES TO
REBUILD SOME INSTABILITY. HOW MUCH INSTABILITY IS ABLE TO REDEVELOP
WILL GO ON TO DETERMINE TWO THINGS...HOW WIDESPREAD WEDNESDAY
AFTERNOON/EVENING ACTIVITY WILL BE AND WHAT POTENTIAL THERE WILL BE
FOR ANY OF THAT TO BE SEVERE. CURRENT THINKING IS THAT THE CLOUD
COVER WILL BE QUITE EXTENSIVE...SO THINK THAT WILL LIMIT THE
INSTABILITY...WHICH WILL IN TURN KEEP AFTERNOON/EVENING CONVECTION
MORE SCATTERED AND ALSO LIMIT THE THREAT FOR SEVERE WEATHER.
FURTHER DECREASING THE POTENTIAL FOR GETTING WIDESPREAD
THUNDERSTORMS WEDNESDAY AFTERNOON ARE THE FACT THAT WEAK HEIGHT
RISES WILL LIKELY BE OCCURRING IN THE WAKE OF A MORNING
SHORTWAVE...CONVERGENCE ALONG THE SFC BOUNDARY WILL BE
DIMINISHING...AND THE LLJ NEVER LOOKS TO RECOVER FROM ITS
DIMINISHING TREND FROM THE OVERNIGHT HOURS. ALL OF THIS POINTS TO
ACTIVITY BEING MORE HIT-OR-MISS ALONG THE FRONT WEDNESDAY
AFTERNOON...WITH THE SEVERE THREAT BEING LIMITED TO A FEW STRONGER
STORMS CAPABLE OF PRODUCING MARGINALLY SEVERE HAIL AND WIND GUSTS.
OF COURSE IF ACTIVITY TONIGHT INTO WEDNESDAY MORNING IS NOT AS
WIDESPREAD AS CURRENTLY EXPECTED...PRETTY MUCH THE OPPOSITE CAN BE
EXPECTED WITH THE THUNDERSTORM POTENTIAL WEDNESDAY
AFTERNOON/EVENING.

FOR THURSDAY INTO FRIDAY WE WILL BE WITHIN A POST FRONTAL
ENVIRONMENT...WITH NORTHERLY WINDS ON THURSDAY GIVING WAY TO
NORTHEAST WINDS ON FRIDAY. AS A RESULT...FEEL THE GFS IS STILL WAY
TO OVERDONE WITH THE EXTENT OF PRECIPITATION IT HAS ACROSS THE MPX
AREA ON THURSDAY AND INSTEAD PREFER THE MUCH DRIER SREF/NAM/ECMWF
SOLUTIONS. FOR FRIDAY...NORTHEAST SFC WINDS DO NOT EXACTLY SCREAM
THUNDERSTORM POTENTIAL...SO THINK FRIDAY WILL BE DRY. WE PRETTY
MUCH HAD CHANCE POPS AREA WIDE ON FRIDAY...SO CUT THOSE IN HALF AT
THIS POINT RATHER THAN GO STRAIGHT TO NOTHING...BUT IF CURRENT
TRENDS CONTINUE...FUTURE SHIFTS CAN PROBABLY CONTINUE TO DECREASE
POPS.

FOR THE WEEKEND...THE MAIN CHALLENGE THE MODELS ARE DEALING WITH ARE
WHEN/HOW MUCH ENERGY EMANATING FROM THE TROUGH/CLOSED LOW OVER THE
ROCKIES WILL PHASE WITH A SHORTWAVE MOVING ACROSS SRN CANADA. THE
02.00 ECMWF WAS THE MOST AGGRESSIVE WITH THIS PHASING AND SENDS A
NEARLY 1000MB LOW ACROSS I-90 SATURDAY NIGHT...WITH A GOOD SLUG OF
QPF FALLING ACROSS THE MPX AREA. THE GFS HAS MAINTAINED MORE
SEPARATION BETWEEN THESE FEATURES AND A MUCH WEAKER WAVE AND
ASSOCIATED FRONT WORKING ACROSS THE AREA...WITH MUCH LESS RAINFALL
ACROSS THE MPX AREA AS A RESULT. THE ECMWF HAD BEEN TREATING THE
WEEKEND WAVE SIMILAR TO WHAT THE GFS HAS...SO NOT REALLY READY TO
BITE OFF ON THE STRONGER SOLUTION THE ECMWF CAME IN WITH TONIGHT.

NEXT WEEK...HAD TO LINGER SOME POPS IN THE EAST ON MONDAY BEHIND THE
WEEKEND FRONT AS BOTH THE GFS/ECMWF GENERATED SOME LIGHT QPF WITH
INSTABILITY BUILDING MONDAY AFTERNOON BENEATH A COOL TROUGH AT H5.

FOR TEMPERATURES...WEDNESDAY AND THURSDAY WILL BE HIGHLY DEPENDENT
ON THE EXTENT OF CLOUD COVER...BUT THE LESS OF IT THERE IS...THE
BETTER CHANCE THERE WILL BE OF GETTING INTO THE 80S. THERE WILL BE A
MINOR COOL DOWN FRIDAY INTO SATURDAY AS OUR WINDS TURN
EASTERLY...WITH 925-850 TEMPS SUNDAY INTO NEXT WEEK CONDUCIVE TO
SEEING TEMPERATURES AT OR LITTLE ABOVE NORMAL.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1259 PM CDT TUE JUN 2 2015

A FEW WANING SHOWERS WILL AFFECT KAXN AND POSSIBLY KSTC THIS
AFTERNOON...BUT VFR CONDITIONS ARE EXPECTED AREA-WIDE INTO THE
EVENING. GUSTY SOUTHERLY WINDS WILL ALSO PERSIST AHEAD OF THE
SURFACE TROUGH THAT WILL BRING HIGHER SHOWER AND THUNDERSTORM
CHANCES OVERNIGHT AND WEDNESDAY. EXPECT THUNDERSTORMS THAT DEVELOP
OVER THE DAKOTAS TO ADVANCE EASTWARD INTO THE AREA AFTER
05Z...WITH ADDITIONAL DEVELOPMENT POSSIBLE WEDNESDAY AFTERNOON AS
THE COLD FRONT MOVES ACROSS THE AREA. MVFR CLOUD DEVELOPMENT IS
EXPECTED ON WEDNESDAY MORNING AS WELL...WHICH COULD MINIMIZE
DEVELOPMENT OF STRONG THUNDERSTORMS.

KMSP...VFR CONDITIONS THROUGH TONIGHT...WITH SHOWER CHANCES
ARRIVING MAINLY AFTER 09Z...AND THUNDERSTORM CHANCES AFTER 14Z.
ALSO EXPECT MVFR CLOUDS TO DEVELOP BY 18Z.

/OUTLOOK FOR KMSP/
THU...VFR WITH MVFR/IFR POSSIBLE IN TSRA. WIND VARIABLE 5 KTS.
FRI...VFR WITH MVFR/IFR POSSIBLE IN TSRA. WIND E 10 KTS.
SAT...VFR. WIND ENE 10 KTS.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&

$$

SHORT TERM...BORGHOFF
LONG TERM...MPG
AVIATION...LS


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