Area Forecast Discussion
Issued by NWS Twin Cities, MN

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000
FXUS63 KMPX 070001
AFDMPX

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

.UPDATE...FOR 00Z AVIATION DISCUSSION BELOW

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 359 PM CDT WED MAY 6 2015

SFC ANALYSIS DEPICTS A WMFNT SNAKING SEWD
FROM E-CENTRAL SD THROUGH SRN MN INTO NRN PORTIONS OF THE OHIO
VALLEY REGION. THIS IS EVIDENCED NICELY ON VIS SAT IMAGERY WITH
CLOUD STREAKS IN A SIMILAR FASHION WITH SOME CLEARING IN THE WAKE OF
THE WMFNT GOING S THRU IA. IN ADDITION...A NARROW LINE OF
SHWRS/TSTMS SHOWS UP ON KMPX RADAR MOVG NWD BUT WITH LIMITED
LIGHTNING...AND SIMILARLY LIMITED QPF PER KMPX RAINFALL TOTALS.
ALOFT...FLOW IS GENERALLY S TO SW WITH A KICKER UPR LVL TROF AXIS
SWINGING NWD FROM THE CENTRAL PLAINS AND MID-MISS RIVER VALLEY
REGION. THE CURRENT PRECIP IS MAINLY DUE TO A WEAKER UPR LVL TROF
DISTURBANCE AND THE WMFNT. ONCE THIS PRECIP LINE CLEARS...THEN
CLOUDS WILL FILL IN OVER MUCH OF THE AREA LATE THIS EVE THROUGH THE
OVERNIGHT HOURS. AS THE LARGER TROF AXIS TO THE SW APPROACHES DURING
THE PRE-DAWN HRS...ANOTHER ROUND OF MORE WIDESPREAD RAIN/TSTMS IS
EXPECTED FOR THE START OF THE DAY THURSDAY...LINGERING THROUGH AT
LEAST MIDDAY...BEFORE JUST LIGHTER SHOWERS LOOK TO PERSIST FOR MUCH
OF THE REMAINDER OF THE DAY. THERE IS SOME CONCERN THAT LATE-DAY
CONVECTION IN ADVANCE OF A CDFNT PUSHING EWD THRU THE NRN-CENTRAL
PLAINS MAY HAVE ENOUGH CLEARING AFTER THE MORNING CONVECTION TO
RELOAD INSTABILITY IN THE ATMOS AHEAD OF THE FRONTAL LIFT. THIS MAY
ALLOW FOR ISOLD STRONG/SEVERE TSTM DEVELOPMENT IN FAR SERN PORTIONS
OF THE CWFA LATE IN THE DAY. CHANCES ARE QUITE LOW...BUT SPC DID
EXTEND THE MARGINAL RISK INTO SERN MN AND SWRN WI FOR THU FOR A
HAIL/WIND RISK. MODEL QPF AMOUNTS HAVE INCRD A BIT LAST NIGHT THRU
TDA AND THIS IS REFLECTED IN THE LATEST FCST THINKING...MORE IN THE
ONE QUARTER TO ONE HALF INCH RANGE CWFA-WIDE ALTHOUGH ISOLD
LOCATIONS WITH STRONG STORMS/HEAVY RAINFALL COULD PICK UP UPWARDS OF
AN INCH THROUGH TMRW AFTN.

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 359 PM CDT WED MAY 6 2015

THURSDAY EVENING THROUGH SATURDAY EVENING: THE MAIN FOCUS FOR THIS
PERIOD WILL BE PRECIPITATION CHANCES THROUGH FRIDAY MORNING AS A
COLD FRONT MOVES EASTWARD THROUGH MN AND WI.

A MID-LEVEL SHORTWAVE FEATURE WILL MOVE NORTHEASTWARD THROUGH MN ON
THURSDAY EVENING BEFORE MOVING INTO ONTARIO ON FRIDAY.  THE SURFACE
LOW WILL ALREADY BE IN WESTERN ONTARIO BY 00Z ON THURSDAY EVENING,
BUT A TRAILING COLD FRONT IS EXPECTED TO STRETCH SOUTHWARD THROUGH
CENTRAL MN AT THIS TIME.  SCATTERED STRONG THUNDERSTORMS...WITH
POSSIBLY AN ISOLATED SEVERE STORM...COULD PERSIST AHEAD OF THE FRONT
DURING THE EVENING HOURS AS CAPE VALUES FROM 500-1500 J/KG AND 0-6
KM BULK SHEAR OF 20-30 KTS ARE POSSIBLE FROM 00Z-03Z OVER
SOUTHEASTERN MN AND WEST CENTRAL WI.  COMBINED WITH DECENT MID-LEVEL
LAPSE RATES AROUND 7 C/KM AND THE FRONTAL FORCING...SMALL HAIL AND A
FEW STRONG WIND GUSTS COULD OCCUR OVER OUR SOUTHEASTERN COUNTIES.
THE AFOREMENTIONED PARAMETERS WILL DIMINISH AS THE FRONT MOVES OFF
TO THE EAST...AND PRECIPITATION WILL GRADUALLY TAPER OFF THROUGH
FRIDAY MORNING AS FORCING FROM THE FRONT AND SHORTWAVE MOVES OUT OF
OUR AREA.

COOLER TEMPERATURES WILL RETURN BEHIND THE FRONT FROM FRIDAY
AFTERNOON THROUGH SATURDAY...WITH HIGHS IN THE LOWER 60S AND LOWS IN
THE 40S.  DRY CONDITIONS ARE EXPECTED THROUGHOUT THIS PERIOD AS HIGH
PRESSURE REMAINS IN PLACE.

BY SATURDAY NIGHT...A STRONG LOW PRESSURE SYSTEM IS STILL EXPECTEDTO
BE LIFTING NORTHEAST THROUGH NEBRASKA...WITH THE SURFACE LOW
LIKELY REACHING SOUTHERN MINNESOTA BY SUNDAY EVENING. WAA REGIME
PRECIP WILL LIKELY BEGIN SPREADING INTO SOUTHERN MN SUNDAY
MORNING...MAKING FOR A COOL AND WET SUNDAY THROUGH TUESDAY
MORNING TIMEFRAME. IT WILL MAINLY DEPART TO THE EAST LATER TUESDAY
BUT UPPER LEVEL CYCLONIC FLOW MAY KEEP CLOUD COVER AND SHOWERS IN
OUR AREA THROUGH THAT PERIOD.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 701 PM CDT WED MAY 6 2015

WIDELY SCATTERED SHOWERS WILL CONTINUE LIFTING ACROSS CENTRAL
MN/WI THIS EVENING...ALTHOUGH SHOULD SEE A BREAK IN THE ACTIVITY
OVERALL DURING THE OVERNIGHT HOURS. VFR CONDITIONS EXPECTED THIS
EVE...WITH BKN-OVC MVFR CIGS DEVELOPING OVERNIGHT AND INTO THE
EARLY MORNING AS THE NEXT BATCH OF PRECIPITATION /CURRENTLY OVER
EASTERN NEBRASKA AT TAF ISSUANCE/ LIFTS NORTH INTO THE AREA. THIS
AREA OF SHOWERS AND THUNDERSTORMS WILL WANE/DECAY SOMEWHAT AS IT
LIFTS NORTH...BUT STILL EXPECT A DECENT AREA OF SHOWERS TO MOVE
INTO WEST/SOUTH CENTRAL MN BY DAYBREAK THURSDAY...AND GRADUALLY
LIFT EAST/NORTHEAST ACROSS THE AREA DURING THE MORNING. THEN
EXPECT A BREAK DURING THE AFTERNOON...WITH POTENTIAL FOR MORE
DEVELOPMENT /THUNDERSTORMS/ LATE AFTERNOON. SOUTHEAST WINDS SHIFT
TO THE SOUTHWEST ON THURSDAY...WITH SPEEDS AOA 12 KTS.

KMSP...
NOT MUCH PRECIP EXPECTED UNTIL AROUND/AFTER DAYBREAK THURSDAY AS
THE PRECIP OVER NEBRASKA LIFTS NORTH/EAST. VFR CONDITIONS UNTIL
THEN...WITH MVFR CIGS/VSBYS DEVELOPING ONCE THE PRECIP ARRIVES.
SHOULD SEE A BREAK DURING THE AFTERNOON...WITH ANOTHER ROUND OF
ACTIVITY /HIGHER THUNDER CHANCES/ POSSIBLE LATE THURSDAY
AFTERNOON.

/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.
&&

$$


SHORT TERM...JPC
LONG TERM...ADL/SPD
AVIATION...LS


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