Area Forecast Discussion
Issued by NWS Twin Cities, MN

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS63 KMPX 062105
AFDMPX

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

.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 EXEPCTED
TO 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 SUNADY 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 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.
&&

$$

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



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.