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000
FXUS63 KMPX 171712
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1212 PM CDT FRI MAY 17 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 410 AM CDT FRI MAY 17 2013

IN THE SHORT TERM...IT DOES APPEARS SMALL MCS OVER FAR SOUTHERN
MINNESOTA WILL SLOWLY LIFT...DEVELOP NORTHEAST OVER THE EASTERN
PORTION OF THE CWA THROUGH THE MORNING AND INTO THE AFTERNOON.
CURRENTLY MCS IS STRENGTHENING A BIT AND IS DROPPING LOCALLY HEAVY
RAIN.  SOME TRAINING OF INDIVIDUAL CELLS AS WELL...HELPING TO
PROMOTE HEAVIER RAINFALL AMOUNTS.  THE DETERMINISTIC GFS AND ECMWF
HAVE THIS SIMILAR TREND...AS MOISTURE TRANSPORT LIFTS NORTHEAST IN
ASSOCIATION WITH THE SHORT WAVE.  PWATS INCREASE TO ABOUT 1.4 INCHES
THIS MORNING...SO THERE WILL BE SOME DOWNPOURS ASSOCIATED WITH THE
STRONGER CELLS. WILL CONTINUE SOME CATEGORICAL POPS INTO THE EASTERN
PORTION OF THE AREA.  CLOUDS WILL REMAIN OVER MOST OF THE REGION
THROUGH THE DAY.  WILL LIKELY SEE SOME BREAKS IN THE SOUTHWEST...AND
SHOULD SEE TEMPS WARM INTO THE 90S THERE.  60S WILL REMAIN IN THE
EAST.

THE SURFACE WARM FRONT IS FORECAST TO LIFT INTO SOUTHWEST MINNESOTA
WITH WEAK SURFACE LOW IN EASTERN SOUTH DAKOTA BY EVENING.  PRETTY
UNSTABLE AIR DEVELOPS TO THE SOUTH OF THE BOUNDARY.  FORCING LIFTS
NORTH OVERNIGHT...AND REDEVELOPMENT EXPECTED BACK IN THE DAKOTAS
NEAR THE SURFACE LOW.  THIS ACTIVITY WILL MOVE ALONG THE FRONT LATER
TONIGHT. WE COULD SEE SOME SCATTERED CONVECTION DEVELOP AHEAD OF THE
FRONT OVER THE AREA THIS EVENING AS WELL.  WILL CONTINUE TO CARRY
SOME CHANCE POPS BECAUSE OF THIS...AND MORE LIKELY POPS INTO CENTRAL
MN AS ACTIVITY RIDES ALONG AND NORTH OF THE WARM FRONT.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 410 AM CDT FRI MAY 17 2013

COMPLEX WET PATTERN OVER THE WEEKEND WITH THE POTENTIAL FOR SEVERE
WEATHER...THEN THE WET PATTERN CONTINUES THROUGH TUESDAY WITH THE
SLOW PASSAGE OF A SFC LOW PRES CENTER AND ASSOCIATED CDFNT.
COOLER BUT DRIER CONDITIONS THEN EXPECTED FOR THE MIDDLE PORTION
OF NEXT WEEK.

UPPER LEVEL RIDGE AXIS WILL SHIFT TO THE E OF THE REGION
SATURDAY...OPENING UP A PATH FOR PRONOUNCED SWLY FLOW IN ADVANCE
OF A BROAD LONG-WAVE TROUGH OVER THE ROCKIES. THIS LARGE TROUGH
WILL BECOME NEGATIVELY TILTED...HELPING ENHANCE SEVERAL LOW PRES
CENTERS OVER THE NRN AND CENTRAL GREAT PLAINS REGIONS. WITH A DEEP
SLY SFC FLOW DRAGGING MOISTURE UP FROM THE SRN STATES...
INSTABILITY WILL BECOME HEIGHTENED...THE CAP WILL STEADILY
WEAKEN...AND CONVECTION WILL SPREAD FROM W TO E LATE SAT THROUGH
SAT NIGHT. RAIN WITH EMBEDDED TSTMS ARE EXPECTED TO CONTINUE SAT
INTO SUN...WITH THE BEST COVERAGE DURG THE DAY ON SUN. EVEN WITH
THE LACK OF SUNSHINE TO AID DIURNALLY DRIVEN CONVECTION...MLCAPES
ARE FORECAST TO RISE TO THE 2000-2500 J/KG RANGE WITH BULK SHEAR
INCRG TO NEARLY 35 KT. MOST SUSCEPTIBLE TO SEVERE WX ON SAT WILL
BE FAR WRN MN...AND THIS WILL BE LATE...MAINLY DUE TO THE STRONG
LOW AND MID LVL JETTING WITH STEEP LAPSE RATES AND INSTABILITY
BEING ADVECTED IN FROM THE SW RATHER THAN IT BEING DIURNALLY
DRIVEN. COME SUNDAY...THE UPPER TROUGH DIGS FURTHER INTO MUCH OF
THE INTER-MOUNTAIN REGION THROUGH THE PLAINS WHILE UPPER FLOW OVER
THE UPPER MISSISSIPPI RIVER VALLEY BECOMES NEARLY MERIDIONAL. THIS
WILL CONTINUE TO ENHANCE LIFT...BUT THE TIMING OF IT NOW DURING
THE DAY MEANS THAT INSTABILITY WILL ONLY BE ENHANCED FURTHER. TWO
PROMINENT SFC LOWS WILL TREK E...ONE OVER THE DAKOTAS AND ANOTHER
OVER KS. BOTH SHIFT E IN TANDEM...LINKED BY A SFC FNT THAT WILL
ALSO HELP ENHANCE LIFT. THE LACK OF CAPPING WILL AGAIN AID THE
DEVELOPMENT OF FAIRLY WIDESPREAD CONVECTION WITH VERY LITTLE
LIMITING FACTORS TO STRONG/SEVERE STORM DEVELOPMENT. BOTH SAT
NIGHT AND SUN...THE PRIMARY HAZARDS WILL BE LARGE HAIL AND DMGG
WINDS. HOWEVER...THE SECONDARY CONCERN FOR ISOLD TORNADOES COULD
BE REALIZED IF PRONOUNCED MCS DEVELOPMENT OCCURS...AND THIS CANNOT
BY ANY MEANS BE RULED OUT. IN FACT...WHILE ONLY FAR WRN MN IS
HIGHLIGHTED IN THE SWODY2 SLGT RISK AREA FOR SAT...THE SRN HALF
OF MN AND THE SWRN QUADRANT OF WI IS HIGHLIGHTED IN THE SWODY3
SLGT RISK AREA FOR SUN. AGAIN...STEEP LAPSE RATES...ELEVATED BULK
SHEAR AND MLCAPES OVER 2000 K/KG ARE EXPECTED SUN.

BY MON...THE UPPER LOW WILL SITUATE ITSELF OVER SRN MN/NRN IA
WHILE THE SFC LOW BECOMES STACKED UNDERNEATH IT. THE FILLING IN OF
THE SYSTEM WILL BRING THE SEVERE THREAT WAY DOWN...BUT WILL
CONTINUE TO PROMOTE FAIRLY WIDESPREAD AND PERSISTENT RAIN ACRS THE
AREA. WHILE RAINFALL SAT AND SUN WILL BE MORE SCATTERED AND
CONVECTIVE...LEADING TO HIGHLY VARIED RAINFALL TOTALS...THE MORE
WIDESPREAD RAIN MON INTO TUE WILL LEAD TO OVERALL INCREASED
RAINFALL AMOUNTS GOING INTO EARLY NEXT WEEK. WPC QPF AND MODEL QPF
INDICATE AREA-WIDE RAINFALL TOTALS MAY LIKELY RANGE FROM 1.5 TO
3.0 INCHES...WITH ISOLATED AMOUNTS OF 4-5 INCHES POSSIBLE...MAINLY
OVER WRN MN. THIS WILL LIKELY BRING ATTENTION TO HYDROLOGIC
ISSUES... ESPECIALLY FOR RISING RIVER/STREAMS...SO WILL NEED TO
MONITOR HOW THIS EVENT EVOLVES ONCE PAST THE SEVERE WEATHER
THREAT. THE STACKED LOW PRES CENTERS SHIFT INTO WI ON TUE THEN
FURTHER INTO THE GREAT LAKES ON WED...DIMINISHING CHCS FOR PRECIP
GOING INTO THE MIDDLE OF NEXT WEEK.

HOWEVER...WITH THE LESSENED PRECIP CHCS COMES A CHANGE IN
TEMPERATURES. FOR THE WEEKEND...THE NWD-MOVG WMFNT WILL PRESS HIGH
TEMPS INTO THE 70S AND 80S. AS PRECIP BECOMES MORE WIDESPREAD AND
THE UPPER LOW SITS OVHD ON MON...HIGHS DROP BACK TO ARND 70. ONCE
THE CDFNT SHIFTS E THRU THE REGION BY TUE MRNG...HIGHS TUE-THU
WILL ONLY REACH THE LOW-MID 60S. IN ADDITION...BY THE MIDDLE OF
NEXT WEEK...LOW TEMPERATURES WILL DROP INTO THE 40S...WHICH IS
SIGNIFICANT WELL BELOW NORMAL FOR MID-MAY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1159 AM CDT FRI MAY 17 2013

MAY AVIATION CONCERN THIS AFTN IS ASSOCIATED WITH
CONVECTION...ESPECIALLY ACROSS SW/SC/WC MN WHERE INSTABILITY HAS
INCREASED SIGNIFICANTLY SINCE THIS MORNING. ELSEWHERE...RESIDUAL
BOUNDARY LAYER MOISTURE WILL HOLD ONTO HIGH END MVFR CIGS ACROSS
EC MN...AND PORTIONS OF WC WI. HOWEVER..THIS SHOULD BE TEMPORARY
ONCE ENOUGH MIXING IN THE BOUNDARY LAYER DEVELOPS THIS AFTN.
CONVECTION ACROSS SC MN NEAR KAEL WILL BE THE FOCUS ACROSS SE MN
IN THE SHORT TERM...OR UNTIL 21Z. OTHER -SHRA DEVELOPMENT... WAS
ASSOCIATED WITH AN ELEVATED INSTABILITY LAYER IN S MN. THESE SHRA
WILL CONTINUE FOR AREAS OF EC MN AS THE MEAN FLOW REMAINED FROM
THE E/ENE. WILL CONTINUE VCTS FOR KRWF WHERE BEST INSTABILITY
REMAINS THIS AFTN. BUT NOT CONFIDENT ENOUGH TO WARRANT IFR/MVFR
CIGS/VSBYS IN TSRA. AFT 00-3Z/18...THE MAIN ACTIVITY SHOULD FOCUS
ACROSS SD...AND INTO WC MN DURING THE OVERNIGHT HRS. MVFR/IFR CIGS
MAY REDEVELOP IN THE WAKE OF THE BOUNDARY LAYER MOISTURE HOLDING
ACROSS THE REST OF MN AND WC WI. WINDS WILL REMAIN FROM THE E/ESE
THIS AFTN AND GUSTY EARLY...BECOMING MORE SE/SSE BY SATURDAY
MORNING.

KMSP...

MVFR CIGS WILL LIKELY CONTINUE THRU 21Z WITH A PERIOD OF
SHRA...LIMITING VSBYS ARND 5-6SM. CIGS SHOULD LIFT TO LOW END VFR
BY THE AFTN...AND CONTINUE THRU THE EVENING...BEFORE LOWERING BACK
TO MVFR OVERNIGHT. SFC WINDS WILL REMAIN FROM THE ESE AND GUSTY
THIS AFTN ARND 20 KTS...THEN BECOME MORE SE/SSE SATURDAY MORNING.

/OUTLOOK FOR KMSP/

SAT NGT...VFR/MVFR CIGS. CHC IFR IN HEAVIER TSRA. SE-S WINDS 5-10 KTS.
SUN...VFR/MVFR CIGS. CHC IFR IN HEAVIER TSRA. S-SE WINDS 8-12 KTS.
MON...VFR/MVFR CIGS. CHC SHRA CHC IFR IN TSRA. S WIND 10-15 KTS.

&&

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

$$

SHORT TERM...DWE
LONG TERM...JPC
AVIATION...JLT