National Weather Service Raw Text Product

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