Area Forecast Discussion
Issued by NWS Twin Cities, MN

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000
FXUS63 KMPX 301649
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1149 AM CDT TUE JUN 30 2015

.UPDATED TO INCLUDE 18Z AVIATION DISCUSSION BELOW.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 400 AM CDT TUE JUN 30 2015

TODAY AND TONIGHT...SFC ANALYSIS SHOWS A CDFNT DRAPED FROM NEAR
KGRB TO THE IA/MN BORDER THEN SNAKING BACK NWWD INTO THE
CENTRAL-WRN DAKOTAS. THE UPR LVL LOW RESPONSIBLE FOR NUDGING THE
SFC FRONT SWD IS SHIFTING EWD THRU THE NRN GRT LKS AND AWAY FROM
THE AREA. ANY LINGERING PRECIP ACTIVITY HAS LONG SINCE DIMINISHED
EARLY THIS MRNG...AND WITH SFC HIGH PRES COMBINED WITH SLIGHT H5
AND H7 HEIGHT RISES...INDICATING MINOR UPR LVL RIDGING...PLUS
DRIER AIR MOVG INTO THE REGION BEHIND THE FRONT...TUE WILL BE
DEVOID OF PRECIPITATION.

THE ONLY REAL CONCERN IS FOR FOG DEVELOPMENT IN WRN WI INTO ERN MN
WHERE WINDS ARE NEARLY CALM AND DECOUPLING FROM 15-20KT WINDS
WITHIN THE BLYR HAS BEEN BETTER ESTABLISHED. METARS HAVE GENERALLY
REPORTED 2-4SM VSBY WITH THE OCNL 1/2SM-1/2SM REPORT. SINCE DENSE
FOG ONLY HAS SPOTTY COVERAGE THIS MRNG...HAVE OPTED TO HOLD OFF
ISSUING A DENSE FOG ADVY. WILL MONITOR TRENDS THRU THIS MRNG...BUT
AM THINKING ONLY AREA FOG MENTION SHOULD SUFFICE.

OTHERWISE...A MIX OF CLOUDS SUN AND CLOUDS WILL PREVAIL THRU THE
DAY TDA...WITH PTLY CLDY SKIES CONTINUING INTO TNGT AS MODEST
UPR LVL RIDGING PLUS WEAK SFC HIGH PRES WILL KEEP PRECIP STREAMS
OFF TO THE W AND S OF THE WFO MPX CWFA.

SLIGHTLY COOLER AND LESS HUMID CONDS CAN BE EXPECTED TDA BEHIND
THE FRONT WITH HIGHS RANGING 70-80 DEGREES AND DEWPOINTS
DROPPING INTO THE 50S. AS SUCH...THIS WILL LEAD TO COOLER TEMPS
TUE NIGHT WITH LOWS FROM THE UPR 40S IN WRN WI TO THE UPR 50S IN
WRN MN.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 400 AM CDT TUE JUN 30 2015

THE MAIN CHANGES TO THE FORECAST IN THE LONG TERM WAS TO TRIM MUCH
OF THE LOW END POPS ACROSS WESTERN WI AND EASTERN MN FURTHER
WEST...SO THE FORECAST READS QUITE A BIT DRIER IN THESE AREAS
THROUGH SATURDAY.

HIGH PRESSURE OVER ONTARIO THIS MORNING WILL DRIFT SOUTH INTO THE
WESTERN GREAT LAKES.  THE LOW LEVEL DRY AIR INTRUSION WILL SPREAD
FURTHER EAST BY TOMORROW.  THE NEWEST RUNS OF THE GFS/EC/NAM/SREF
ALL PUSH THE QPF FURTHER WEST...AND THE REFLECTIVITY FORECAST OFF
THE ARW AND NMM INDICATE ALL ACTIVITY TO REMAIN ACROSS WESTERN MN
AN THE EASTERN DAKOTAS...WHICH MAKES SENSE GIVEN THE SHORTWAVE
WILL MAINLY PASS OVER THE EASTERN DAKOTAS WITH THE PV ADVECTION
AND Q- VECTOR CONVERGENCE FOCUSED THERE. THIS WAVE WILL DEPART
WEDNESDAY NIGHT...AS POPS AGAIN ARE PULLED BACK TO THE WEST AHEAD
OF THE NEXT WAVE.

THE WAVE ON THURSDAY LOOKS A BIT STRONGER...BUT WILL FOLLOW A
SIMILAR PATH THROUGH THE EASTERN DAKOTAS. STRONGER AND DEEPER
FORCING LOOKS LIKELY...WITH STRONG DIFFERENTIAL DIVERGENCE MOVING
FROM NEAR ABERDEEN...THROUGH SIOUX FALLS AND CONTINUING SOUTHEAST
OF THERE...SO A GLANCING BLOW FOR OUR FORECAST AREA. THE ECMWF
HAD BEEN AN OUTLIER IN CONTINUING TO SHOW PRECIP POTENTIAL
THURSDAY NIGHT ACROSS EASTERN MN AND WESTERN WI...BUT THE 00Z RUN
CAME IN MORE IN LINE WITH A DRY FORECAST FOR THIS AREA AND LOOKS
TO BE IN GOOD AGREEMENT WITH THE NAM/GFS/SREF WHICH ALL INDICATE A
FRY FORECAST FOR EASTERN MN AND WESTERN WI THURSDAY AND THURSDAY
NIGHT.

DAILY TEMPERATURES THROUGH FRIDAY WILL BE VERY CONSISTENT AS THE
THERMAL FIELD STAYS MAINLY STAGNANT AS WE REMAIN BETWEEN THE
WESTERN RIDGE...AND THE UPPER TROUGH TO OUR EAST.

FOR THIS WEEKEND...THE SURFACE HIGH OVER THE GREAT LAKES WILL BE
PULLING AWAY...MOVING EAST.  SOUTHERLY LOW LEVEL FLOW WILL
INCREASE...AND THE TEMPERATURES WILL BEGIN INCREASING OVER THE
PREVIOUS FEW DAYS.  THE FOCUS FOR THIS PERIOD WILL BE A STRONGER
SYSTEM DEVELOPING IN CANADA AND PUSHING A COLD FRONT ACROSS OUR
AREA...WHICH LOOKS TO BE LATE IN THE WEEKEND.  CONTINUED A DRY
FORECAST FOR INDEPENDENCE DAY...BUT IN THE SOUTHERLY FLOW WE MAY
SEE SOME INSTABILITY DEVELOP BY THE AFTERNOON. AT THIS POINT
HOWEVER...THE GFS AND ECMWF INDICATE THAT ANY CONVECTIVE
DEVELOPMENT WILL BE NORTH OF OUR AREA DURING THAT TIME...SO I FELT
OK LEAVING A DRY FORECAST IN PLACE BUT AGAIN LATER FORECASTS WILL
NEED TO EVALUATE THIS PERIOD AND POSSIBLY ADD LOW POPS DEPENDING
ON THE TIMING OF THE APPROACHING SYSTEM.

THE GFS/EC AGREE ON THE COLD FRONT SWEEPING THROUGH THE UPPER
MIDWEST...BUT DISAGREE ON TIMING. THE EC IS ABOUT 12 HOURS FASTER
AND BRINGS THE FRONT....AND THUNDERSTORMS ALONG IT...THROUGH THE
AREA SUNDAY...WHERE THE GFS DOES SO SUNDAY NIGHT INTO MONDAY. SO
WE`LL LIKELY BE DEALING WITH THUNDERSTORMS AT THE END OF THE
WEEKEND...BUT THE EXACT TIMING WILL NEED TO BE SORTED OUT.
TEMPERATURES COULD WARM WELL INTO THE 80S AHEAD OF THE COLD FRONT
ON SUNDAY.

ON THE HEELS OF THIS SYSTEM...NORTHWEST FLOW WILL DRIVE COOLER
TEMPERATURES AND A CANADIAN SURFACE HIGH DOWN INTO THE UPPER
MIDWEST BY TUESDAY...SO EXPECT A COOLING TREND TOWARD THE MIDDLE
OF NEXT WEEK.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1145 AM CDT TUE JUN 30 2015

MVFR CIGS OVER EASTERN AREAS ARE LIFTING AND BECOMIING MORE
SCATTERED INTO WEST CENTRAL WISCONSIN. EXPECT THIS TREND TO
CONTINUE WITH PERHAPS A LINGERING MVFR CIG FROM THE SOUTHEAST
METRO INTO SOUTHEAST MN THROUGH ABOUT 19Z. THEN SOME MID/HIGH
LEVEL CLOUDS DRIFTING INTO FAR WESTERN MN INTO THE EVENING WITH
PERHAPS A SHOWER/ISOLATED THUNDER INTO FAR WEST MAINLY AFTER 06Z.
THIS SHOULD GRADUALLY MOVE OUT THROUGH MID MORNING WITH MID CLOUDS
REMAINING TOT HE WEST FOR THE MOST PART. SHOULD MAINTAIN VFR
HOWEVER. SURFACE WINDS ARE EXPECTED TO BE NE-E DIRECTION INTO THE
AFTERNOON...AND BECOMING MORE SOUTHEAST TO THE FAR WEST INTO THE
LATE NIGHT/WEDNESDAY MORNING.

KMSP...CONTINUE VFR FORECAST THROUGH THIS FCST PERIOD. NO
SIGNIFICANT WX IMPACTS EXPECTED.

/OUTLOOK FOR KMSP/
WED...VFR. WINDS E-SE AT 5-10 KTS.
THU...VFR WITH SLGT CHC MVFR -TSRA. WINDS SE AT 5-10 KTS.
FRI...VFR WITH SLGT CHC MVFR -TSRA. WINDS WSW 5-10 KTS.

&&

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

$$

SHORT TERM...JPC
LONG TERM...SPD
AVIATION...DWE



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