Area Forecast Discussion
Issued by NWS Twin Cities, MN

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000
FXUS63 KMPX 061835
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
135 PM CDT WED MAY 6 2015

.UPDATE...
ISSUED AT 119 PM CDT WED MAY 6 2015

UPDATED TO INCLUDE 18Z AVIATION DISCUSSION BELOW.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 410 AM CDT WED MAY 6 2015

THE SHORT TERM CONCERNS ARE FOG THIS MORNING...TIMING AND EXTENT
OF CONVECTION AND TEMPERATURES.

DENSE FOG ALONG THE MN/IA BORDER THIS MORNING...AHEAD OF WARM
FRONT OVER IOWA. THE STRATUS AND FOG ARE EXPECTED TO REMAIN
THROUGH AT LEAST MID MORNING...THEN LIFTING THEREAFTER. THE MOST
DENSE FOG WILL AFFECT THE SOUTHERN TWO TIER OF COUNTIES AND AN
ADVISORY WAS ISSUED AROUND MIDNIGHT FOR THIS.

THE BAND OF SHOWERS DEVELOPED FROM THE METRO EAST INTO WISCONSIN
OVERNIGHT AND SHOULD EXIT THERE BY AROUND 12Z.  OTHER
SHOWERS/ISOLATED THUNDER LIFTING NORTH/NORTHWEST ACROSS CENTRAL
IOWA...AND WILL AFFECT MAINLY WESTERN AREAS THROUGH THE MORNING.
WILL HOLD ONTO HIGHER POPS TO THE WEST AND NORTH WITH SOME LOWER
POPS/SLIGHT CHANCE DEVELOPING INTO WESTERN WISCONSIN THROUGH THE
MORNING.  CLOUDS WILL HOLD FIRM MUCH OF THE DAY...PERHAPS BREAKING
OUT SOME DURING THE AFTERNOON.  DEWPOINTS EXPECTED TO REMAIN CLOSE
TO 60F WHICH WILL FEEL A BIT MUGGY.  TEMPERATURES SHOULD WARM
THROUGH THE 70S...BUT COULD WARM TO 80 IF THE SUN BREAKS OUT INTO
THE AFTERNOON IN THE SOUTHWEST.

WATER VAPOR IMAGERY SHOWING NEXT STRONG WAVE OVER OKLAHOMA/KANSAS
REGION...WHICH WILL LIFT NORTHEAST TOWARD IOWA BY LATE AFTERNOON.
SHOULD SEE SHOWER/THUNDER INCREASE FROM WEST TO EAST DURING THE
AFTERNOON. THEN ACTIVITY SHOULD WANE INTO THE LATE EVENING BEFORE
THE BRUNT OF THE UPPER TROUGH MOVES INTO THE AREA LATER TONIGHT.
THIS WILL SPREAD LIKELY/CATEGORICAL POPS EAST ONCE AGAIN THROUGH
12Z THU. THE SEVERE WEATHER THREAT IS CONDITIONAL AT BEST...WITH
THE AMOUNT OF CLOUD COVER/LIMITED HEATING EXPECTED.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 410 AM CDT WED MAY 6 2015

THE SHORT TERM ADDRESSES THE PRECIP LATE TONIGHT WITH A PRONOUNCED
LLJ AND STRONG MOISTURE TRANSPORT. IN FACT...THERE IS REALLY GOOD
CONSENSUS AMONG THE NAM/GFS/ECMWF OF A 40-50KT JET NOSING INTO
MN/WI BY SUNRISE THURSDAY MORNING. THIS WILL ALLOW THE WARM FRONT
TO SURGE NORTHWARD AND SHOULD LEAD TO WIDE-REACHING SHOWERS AND
WEAK THUNDERSTORMS THURSDAY MORNING...ESPECIALLY ACROSS WESTERN
AND CENTRAL MN. THE RAIN IS EXPECTED TO PERSIST THROUGHOUT THE DAY
ON THURSDAY AND THERE IS ALSO GOOD AGREEMENT AMONG GUIDANCE TO
LIGHT UP A LOT OF CONVECTION ALONG THE COLD FRONT IN MN THURSDAY
AFTERNOON AND EVENING. THIS SEEMS REASONABLE GIVEN THE STRENGTH OF
THE FGEN AND AMOUNT OF MOISTURE EXPECTED TO BE IN PLACE. THERE IS
ALSO BETWEEN 500-1500J/KG OF MUCAPE ACROSS THE FORECAST AREA
THROUGHOUT THE DAY THURSDAY.

FRIDAY WILL LIKELY SEE A HEALTHY AMOUNT OF CLOUD COVER...BUT THE
PRECIP WILL HAVE LARGELY SHIFTED EAST BY THE TIME WE REACH THE END
OF THE WORK WEEK. AFTER THE COLD FRONT PASSES THROUGH ON
THURSDAY...THE STAGE WILL BE SET FOR A COOL DOWN FOR THE WEEKEND
INTO EARLY NEXT WEEK. WE WILL LIKELY SEE TEMPS FALL BACK INTO THE
40S AND 50S EARLY NEXT WEEK WITH A NICE POCKET OF COLD AIR THAT
MAKES ITS WAY DOWN IN NORTHWEST FLOW. THE THERMAL PROFILE IS WARM
ENOUGH FOR ALL RAIN ON SUNDAY...BUT THE TREND OF THE WET BULB ZERO
/WBZ/ LEVEL WITH TIME IS INTERESTING WITH THE WBZ ACTUALLY GETTING
BELOW 1000FT EARLY TUESDAY MORNING FOR AT LEAST A FEW HOURS. A WBZ
BELOW 1000FT IS SOMETIMES A GOOD FIRST GUESS AT WHETHER OR NOT THE
BOUNDARY LAYER IS WARM ENOUGH TO MELT THE SNOWFLAKES BEFORE THEY
REACH THE GROUND. THE TRACK FOR MONDAY`S RAIN MAKER IS STILL A BIT
UNCERTAIN IN TIMING AND PRECISE PLACEMENT.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 119 PM CDT WED MAY 6 2015

COMPLICATED 06/18Z TAF SET DUE TO PATCHES OF LOW CLOUDS BEING
QUICKLY ERODED FROM THE S AT THE START THEN OCNL PERIODS OF
SHWRS/TSTMS NEEDING TO BE TIMED INTO AND OUT OF THE TERMINALS.
STARTED OUT TRYING TO SHOW IMPROVEMENT FROM S TO N THROUGH THE
TERMINALS...GOING FROM LIFR/IFR TO VFR...BUT THERE MAY WELL STILL
BE SOME BANDS THAT RACE NWD BEFORE DARK. AFTER A LULL FOR MUCH OF
THE OVERNIGHT PERIOD...ADDITIONAL SHWRS/TSTMS LOOK TO DEVELOP FROM
THE W AND SW AND GRADUALLY PUSH ACRS THE AREA MID-MRNG THRU
EARLY-AFTN THU. HAVE TEMPERED TSTM PROSPECTS TMRW MRNG TO A PROB30
GROUP RATHER THAN A TEMPO GROUP DUE TO HIGHER UNCERTAINTY AND
TIMING ISSUES...BUT CONFIDENCE IS HIGH ENOUGH TO AT LEAST INCLUDE
TSTM MENTION FOR TMRW.

KMSP...WAITING FOR MSP TO BREAK OUT FROM THE SUB-1700FT CLOUD DECK
AT INITIALIZATION...ESPECIALLY CONSIDERING ALL SURROUNDING SITES
HAVE ALREADY DONE SO. WILL SEE VFR CONDS FOR MUCH OF THE EVENING
AND OVERNIGHT HOURS...ASIDE FROM OCNL BOUTS OF SHWRS/TSTMS AROUND
THE 00Z HOUR. MORE CONSISTENT RAINFALL WITH EMBEDDED TSTMS LOOKS
TO DEVELOP DURG THE PRE-DAWN HOURS THEN REMAIN THERE FOR MUCH OF
THE AFTN...AND THESE MAY CONTAIN ADDITIONAL PERIODS OF MVFR OR
EVEN IFR CONDS IF RAINFALL IS HEAVY ENOUGH.

/OUTLOOK FOR KMSP/
FRI...VFR. WINDS NW 10 KTS.
SAT...VFR. WINDS NE 10 KTS.
SUN...MVFR LIKELY WITH IFR POSSIBLE IN SHWRS/TSTMS. WINDS NE 10-15
KTS.

&&

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

$$

UPDATE...JPC
SHORT TERM...DWE
LONG TERM...CLF
AVIATION...JPC


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