908 FXUS63 KMPX 200907 AFDMPX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 407 AM CDT MON MAY 20 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 400 AM CDT MON MAY 20 2013 TODAY-TONIGHT...BROAD UPPER LEVEL CENTRAL CONUS TROUGH WILL SLOWLY MEANDER TWD THE E...WITH ITS CUTOFF LOW WOBBLING OVER WRN MN AND THE ERN DAKOTAS. SEVERAL SHORTWAVE SPOKES WILL ROTATE ARND THIS UPPER LOW...SWINGING THRU THE MPX CWFA TDA INTO TNGT. THE MAIN ISSUES ARE AROUND TIMING OF PRECIP AND POTENTIAL FOR SEVERE WX IN FAR ERN MN INTO WRN WI. SCATTERED SHWRS THIS MRNG WILL CONTINUE TO DEVELOP AND DISSIPATE AS MODELS INDICATE DRY SLOTTING TO SHIFT NE INTO THE REGION THIS MRNG...LASTING THRU AT LEAST MID AFTN. THIS WOULD HALT ANY WIDESPREAD PRECIP BUT ISOLD TO SCATTERED SHWRS/TSTMS CERTAINLY CANNOT BE RULED OUT. ONCE THIS DRY SLOTTING SHIFTS WELL INTO NRN MN AND NW WI BY THIS EVE...ANOTHER SWATH OF MOISTURE WILL BR DRAGGED INTO THE REGION WHICH WILL BE ABLY TAPPED TO PRODUCE ADDITIONAL BANDS OF PRECIP...IF NOT A LARGE PRECIP SHIELD. ONE DETERMINING FACTOR WILL BE THE PLACEMENT OF THE SFC LOW UNDER THE UPPER LOW. THE SFC LOW LOOKS TO REMAIN PRIMARILY NEAR THE ND/SD/MN TRIPLE POINT... AND THIS POSITION WOULD KEEP THE BULK OF THE PRECIP ALONG AND N OF ITS LATITUDE. AS FOR SEVERE WX POTENTIAL...THE EWD SHIFT OF THE UPPER TROUGH PUTS THE BEST JETTING AND EXIT REGION OVER FAR ERN MN AND WRN WI. IN ADDITION...THE BREAK IN THE PRECIP MAY ALLOW FOR A FEW BREAKS IN THE OVERCAST...ALLOWING FOR ADDITIONAL INSTABILITY...ESP IN WRN WI WHERE PRECIP HAS NOW VIRTUALLY SHUT DOWN EVERYWHERE. THIS WILL ALLOW A RELOADING OF THE ATMOS TO GENERATE MLCAPE IN THE 2000-2500 J/KG RANGE WITH LITTLE CAPPING...WHILE CENTRAL-WRN MN WILL BE DEALING WITH LESS IMPRESSIVE LAPSE RATES AND INSTABILITY PARAMETERS. STILL HAVE A SLGT RISK IN PLACE PER SPC IN THEIR SWODY1 FOR ALL OF FAR ERN MN THRU WI WHICH IS VERY REASONABLE. AS FOR TEMPERATURES AND DEWPOINTS...WITH THE WMFNT CONTINUING TO LUMBER NWD THRU THE CWFA AND ITS TRAILING CDFNT STILL IN THE DAKOTAS...ANOTHER WARM/HUMID DAY CAN BE EXPECTED. WILL LOOK FOR HIGHS FROM ARND 70 IN WRN MN TO THE LOWER 80S IN WRN WI... WITH LOWS TNGT AGAIN MILD IN THE MID 50S TO LWR 60S. DEWPOINTS WILL AGAIN REACH THE LWR 60S...KEEPING AN UNSEASONABLY HUMID AIRMASS IN PLACE. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 400 AM CDT MON MAY 20 2013 IT ISN'T UNTIL TUESDAY NIGHT/WEDNESDAY MORNING THAT WE FINALLY SEE SOME SLOW EASTWARD PROGRESS WITH THE TROUGH OVER THE CENTRAL CONUS. DURING THIS TIME THE SURFACE LOW SLOWLY FILLS AND MOVES FROM MN TO WI. HOWEVER...BEFORE THEN...DURING THE DAY ON TUESDAY...WE EXPECT SCATTERED SHOWERS ACROSS PRIMARILY CENTRAL MN AND NORTHERN WI. JUST LIKE THIS MORNING...WHERE WE SEE GOOD DRYING SHOWING UP IN THE WATER VAPOR IMAGERY ACROSS EASTERN NE AND WESTERN IA...TUESDAY SHOULD SEE A DRY SLOT ACROSS THE SOUTHERN HALF OF THE FORECAST AREA. BETTER Q-VECTOR CONVERGENCE AND SLIGHTLY BETTER FGEN IS LOCATED ACROSS THE NORTHERN FORECAST AREA JUST NORTH OF THE DRY WEDGE SHIFTING NORTHEAST DURING THE DAY. AS A RESULT...KEPT HIGH CHANCE POPS OR LIKELY POPS IN THE FORECAST FOR THE NORTHERN CWA...BUT LOWERED POPS OR WENT NO WEATHER IN THE SOUTHERN CWA TUE/TUE NIGHT. LINGERING INSTABILITY IN EASTERN MN AND WESTERN WI WARRANTS THUNDERSTORMS FOR THE WEATHER TYPE ON TUESDAY...BUT EVEN BEFORE TUESDAY NIGHT THE MUCAPE SLIDES FARTHER EASY AND DIMINISHES. THEREFORE...KEPT THE THUNDER OUT OF THE FORECAST IN MOST LOCATIONS TUESDAY NIGHT AND WEDNESDAY. WE ALSO COOLED TEMPERATURES A BIT ON WEDNESDAY...ESPECIALLY ACROSS CENTRAL MN...WHERE LIGHT SHOWERS MAY BE MORE WIDESPREAD AND HANG AROUND LONGER. ALSO...WITH EAST-SOUTHEAST SHIFT TO THE SYSTEM ON WEDNESDAY...THE BETTER LARGE-SCALE FORCING SHOULD GET PULLED ACROSS THE AREA. SO WEDNESDAY'S POPS ARE ACTUALLY HIGHER THAN TUESDAY'S AND ARE COMPARABLE TO THE PROBABILITIES FORECASTED TODAY. HOWEVER...THE QPF IS LOW. LOOKS LIKE WE'LL GET A BRIEF REPRIEVE FROM THE WET WEATHER THURSDAY AND FRIDAY WITH A SURFACE HIGH BUILDING IN TROUGH...RIDGE...TROUGH PATTERN SETTING UP ACROSS THE CONUS. THE WEATHER PREDICTION CENTER PREFERS A GFS/GEFS/EC/EC-MEAN BLEND IN THE EXTENDED AND TO THAT SEEMS REASONABLE GIVEN THE RELATIVELY SMALL SPREAD IN THE LONG WAVE PATTERN...EVEN WITH AN ANOMALOUSLY DEEP TROUGH ALONG THE WEST COAST. BY THE WEEKEND...A WARM FRONT IS FORECAST TO MOVE EAST ACROSS SD/NE AND APPROACH WESTERN MN. MOST OF THE FORECAST AREA TAKES SOME TIME TO MOISTEN IN LIGHT OF THE DRIER E-SE FLOW UNDER THE RIDGE. NONETHELESS...WITH AT LEAST SOME MOISTURE PLACE...THE WARM ADVECTION COULD KICK OFF SOME SHOWERS BY SATURDAY...ESPECIALLY IN WESTERN MN. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1042 PM CDT SUN MAY 19 2013 THE AREA OF SHOWERS AND THUNDERSTORMS OVER SOUTHEASTERN MN AND WEST CENTRAL WI WILL GRADUALLY FILL BACK IN TO THE NORTH AND WEST ACROSS CENTRAL MN OVERNIGHT...WHICH IS ILLUSTRATED BY THE HRRR MODEL. MVFR CIGS/VSBYS IN THE SHRA ARE EXPECTED...ALONG WITH IFR CIGS FROM KSTC-KAXN. AFTER 15Z MONDAY...EXPECT A LULL IN CONVECTION UNTIL DAYTIME HEATING CAUSES THE NEXT ROUND OF POTENTIALLY STRONG TO SEVERE THUNDERSTORMS TO DEVELOP. WINDS WILL BE SOUTHEASTERLY AOB 10 KTS OVERNIGHT...THEN BECOME GUSTY BY LATE MORNING MONDAY AND VEER SLIGHTLY TO MORE SOUTH/SOUTHWESTERLY IN DIRECTION. KMSP... EXPECT THE SHOWERS OVER SOUTHEASTERN MN TO GRADUALLY EXPAND BACK WEST/NORTHWEST AT THE START OF THE PERIOD...THEN TAPER OFF BY 14Z MONDAY WHEN WINDS BECOME GUSTY. CIGS MAY DIP TO 1500 FT OVERNIGHT WITH THE SHOWER ACTIVITY...BUT THE PREVALENT CIG SHOULD BE 2500-3500FT. SOUTHEAST WINDS AROUND 150 DEGREES BEGIN GUSTING TO 25 KTS BY 15Z...THEN VEER TO AROUND 200 DEGREES BY 18Z WITH GUSTS CONTINUING. /OUTLOOK FOR KMSP/ TUE...VFR/MVFR CIGS. SHRA/TSRA LIKELY. S-SW WIND 5 KTS. WED...VFR/MVFR CIGS. SHRA LIKELY. NE WIND 5-10 KTS. THU...VFR. NE WINDS 10 KTS. && .HYDROLOGY... ISSUED AT 249 AM CDT MON MAY 20 2013 HAVE MAINTAINED FLASH FLOOD WATCH AS-IS THRU THIS FCST PKG BUT CONFIDENCE IS WANING THAT ACTUAL FLASH FLOODING MAY BE ACHIEVED DUE TO DRY SLOTTING MOVING INTO THE REGION THIS MRNG. THIS HAS CUT INTO ADDITIONAL QPF EXPECTED. THAT SAID...MUCH OF THE AREA HAS RECEIVED 2-4 INCHES OF RAIN WITH LOCALLY HIGHER AMOUNTS THE PAST COUPLE OF DAYS...SO SOILS ARE CERTAINLY CLOSE TO IF NOT COMPLETELY SATURATED. THERE MAY NOT BE THE QUINTESSENTIAL FLASH FLOODING THAT DEVELOPS...BUT QUICK RISES IN RIVERS AND STREAMS ALONG WITH URBAN FLOODING DUE TO RUNOFF CERTAINLY CANNOT BE RULED OUT AS ANOTHER ONE HALF TO ONE INCH IS EXPECTED TDA IN MUCH OF THE AREA COVERED BY THE WATCH...ESP IN CENTRAL MN. EVEN THOUGH THE FORECAST IS LOADED WITH SHOWERS THROUGH WEDNESDAY. TODAY APPEARS LIKE THE LAST REMAINING CHANCE TO GET ANY KIND OF QUICK RESPONSE TO LOCAL RIVERS AND STREAMS. WE LOSE THE ENVIRONMENT FOR VIGOROUS DEEP CONVECTION TUESDAY AND WEDNESDAY AND SHOULD JUST GET SCATTERED LIGHT SHOWERS WITH LOWER QPF TOTALS ON BOTH OF THOSE DAYS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...FLASH FLOOD WATCH THROUGH THIS EVENING FOR MNZ041>045-047>053- 057>063-066>070-075>078-084-085-093. WI...FLASH FLOOD WATCH THROUGH THIS EVENING FOR WIZ014>016-023>028. && $$ SHORT TERM...JPC LONG TERM...CLF AVIATION...LS HYDROLOGY...CLF