Area Forecast Discussion
Issued by NWS Twin Cities, MN

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000
FXUS63 KMPX 050031 AAA
AFDMPX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
631 PM CST THU FEB 4 2016

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 310 PM CST THU FEB 4 2016

THE SHORT TERM CONCERNS ARE CLOUD AND TEMPERATURE TRENDS TONIGHT
AND LIGHT SNOW THREAT FRIDAY.

TODAYS LIGHT SNOW MAKER IS EXITING TO THE EAST AT THIS TIME. LIGHT
SNOW SHOULD END OVER THE FAR EASTERN CWA BY 00Z FRI.  CLOUD TRENDS
ARE TRICKY...WITH SOME LARGE SCALE SUBSIDENCE IN THE WAKE OF THE
UPPER TROUGH SCOURING THE CLOUDS TO THE WEST.  HOWEVER...THE NEXT
WAVE IS MOVING ACROSS MONTANA AND WILL HELP TRAP SOME LOW LEVEL
MOISTURE OVER NORTH DAKOTA.  THIS MAY DROP/DEVELOP SOUTHEAST INTO
WESTERN MN DURING THE NIGHT...AND WILL AFFECT THE LOW TEMPERATURE
FORECAST.  EXPECT SOME CLEARING TO THE EAST AS WELL. MID/HIGH LEVEL
CLOUDS SHOULD SPREAD EAST OVER THE AREA AFTER MIDNIGHT AS WELL. WILL
KEEP LOWS IN THE SINGLE DIGITS EAST AND 5 TO 10 ABOVE TO THE WEST
FOR NOW.

ISENTROPIC FORECAST SHOWS DECENT LIFT MOVING FROM WESTERN MN TO EAST
CENTRAL MN BY LATE FRIDAY AFTERNOON. THIS SHOULD BE STRONG ENOUGH
TO GENERATE ANOTHER HIGH POP/LOW QPF EVENT. WENT CATEGORICAL POPS
INTO CENTRAL MN FOR FRIDAY AFTERNOON. ACCUMULATION LOOKS TO RANGE
AN INCH OR LESS.

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 310 PM CST THU FEB 4 2016

CONFIDENCE HAS BEEN INCREASING FOR A POTENTIAL "GROUND" BLIZZARD
LATE SUNDAY/MONDAY ACROSS THE SW 1/3 OF MPX CWA /WC-SW-SC MN/.
SEVERAL FACTORS NEED TO COME TOGETHER FOR THIS SCENARIO TO
DEVELOP.

FIRST...NO CHANGES TO CURRENT FORECAST FRIDAY NIGHT/SATURDAY AS
ANY ADDITIONAL SNOWFALL FROM THE DEPARTING SYSTEM ON FRIDAY WILL
BE MINIMAL...AND MAINLY AFFECTING WESTERN WI DURING THE EVENING.
STRONG SW WINDS AND WAA DEVELOPING SATURDAY WILL LIKELY HOLD
TEMPS OR EVEN RISE THE SFC TEMPS A FEW DEGREES SATURDAY NIGHT.
THIS WILL SET THE STAGE FOR A MIX BAG OF PRECIPITATION ACROSS
CENTRAL MN...AND PARTS OF EC MN/WC WI AS PRECIPITATION BEGINS TO
DEVELOP EARLY SUNDAY MORNING. WC/SW MN WILL LIKELY RISE ABV THE
FREEZING MARK TO KEEP MOST PRECIPITATION TYPE IN THE FORM OF RAIN
OR A MIX OF RAIN/SNOW. HOWEVER...THIS AREA IS ALSO LIKELY TO HAVE
THE LEAST AMOUNT OF PRECIPITATION /QPF/ DUE TO DRIER MID-LEVEL
MOISTURE. CURRENT POPS ARE HIGH END CHC IN CENTRAL/EC MN AND WC
WI...BUT MAY INCREASE TO LIKELY/CATEGORICAL IF WAA AND ASSOCIATED
ISENTROPIC LIFT CREATES MORE WIDESPREAD PRECIPITATION THEN THE
CURRENT WX MODELS INDICATED.

NOW LETS LOOK AT THE POTENTIAL OF A GROUND BLIZZARD SUNDAY
NIGHT/MONDAY ACROSS WC/SW/SC MN....

MODELS HAVE BEEN FAIRLY CONSISTENT FOR DEVELOPING A SFC LOW
ACROSS NORTHERN MN SUNDAY MORNING...AND SHIFTING IT SE ACROSS THE
SOUTHERN GREAT LAKES BY MONDAY NIGHT. ALTHOUGH THE PRESSURE
GRADIENT STRENGTHENS SIGNIFICANTLY SUNDAY AND INTO MONDAY...THE
SFC LOW DOESN/T INTENSIFY /DEEPEN/ BUT ACTUALLY WEAKENS SOME. THE
STRENGTHENING PRESSURE GRADIENT IS ASSOCIATED WITH STRONG CAA AND
HIGH PRESSURE BUILDING ACROSS THE NORTHERN PLAINS. MODELS ALONE
FORECAST A SIGNIFICANT BOUNDARY LAYER WIND OF 25-30 KTS...SO KEPT
SUSTAINED WINDS OF 20-25 KTS ACROSS WC/SW/SC MN FROM SUNDAY
MORNING THRU MONDAY NIGHT. GUSTS COULD APPROACH 35-40 KTS DUE TO A
STRONG DRY ADIABATIC LAPSE RATES DEVELOPING BEHIND THIS SFC LOW
SUNDAY NIGHT. EVEN THE GFS/NAM HAVE 50+ KTS ON THE TOP OF THE MIX
LAYER WHICH IS A VERY STRONG INDICATOR OF VERY WINDY CONDITIONS.
THEREFORE...CONFIDENCE IS HIGH THAT WIND SPEEDS WILL APPROACH OR
EXCEED BLIZZARD WARNING CRITERIA WHICH IS 35 MPH SUSTAINED...OR
FREQUENT GUSTS OF 35 MPH FOR 3 OR MORE HOURS.

NOW LETS DISCUSS THE PROBLEMS ASSOCIATED ON "NOT" GETTING
BLIZZARD TYPE CONDITIONS.

PROBLEMS DEVELOP FOR THE POTENTIAL OF BLOWING SNOW IF NO NEW SNOW
DEVELOPS SUNDAY AFTN/EVENING AS THE MAIN STORM SYSTEM MOVES OFF TO
THE SE. THIS WOULD LEAD TO A "CRUST" DEVELOPING ON TOP OF THE SNOW
COVER AS WARMER TEMPS ARE EXPECTED IN THIS AREA SUNDAY MORNING
BEFORE TEMPS BEGIN TO FALL. USING A BLOWING SNOW MODEL DURING THIS
TIME FRAME ALSO INDICATED THE LOW POTENTIAL OF BLIZZARD TYPE
CONDITIONS. THIS AGAIN IS PROBABLY ASSOCIATED WITH THE LACK OF NEW
SNOW TO BLOW AROUND. ON THE OTHER SIDE...THE LATEST CIPS FOR
MONDAY INDICTED A 30-40 PERCENT CHC OF 1 HOUR OR MORE OF BLIZZARD
TYPE CONDITIONS FOR SW/SC MN. THEREFORE...THE BEST SCENARIO IS TO
HIGHLIGHT THE POTENTIAL OF A GROUND BLIZZARD IN THE HWO AND KEEP
THE PUBLIC ABREAST OF THE SITUATION OVER THE NEXT DAY OR SO.

PAST MONDAY NIGHT...TEMPS WILL DROP TO BELOW NORMAL LEVELS WITH
THE POTENTIAL OF ZERO OR LOWER FOR OVERNIGHT LOWS BY WEDNESDAY
MORNING. THIS COLD SNAP SHOULD BE SHORT LIVED AS ANOTHER WARM UP
IS EXPECTED BY THE FOLLOWING WEEKEND.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 631 PM CST THU FEB 4 2016

BACK EDGE OF MVFR CIGS IS ROUGHLY NEAR I-35 AND HEADED EAST THIS
EVENING. SHOULD REACH RNH BY 0130Z AND EAU BY 04-05Z. ANOTHER
SMALL BAND OF MVFR CIGS NEAR THE MN RIVER OVER WRN MN IS
DIMINISHING AND SHOULD NOT IMPACT AREAS EAST OF AXN/RWF.
OTHERWISE...VFR CONDS GENERALLY EXPECTED UNTIL THE SNOW ARRIVES
FRIDAY AFTERNOON. THERE IS SOME CHANCE OF BR THIS EVENING AND
OVERNIGHT IF WINDS DECOUPLE WHICH WILL BE MONITORED.

KMSP...VFR EXPECTED UNTIL THE SNOW ARRIVES FRIDAY AFTERNOON.

/OUTLOOK FOR KMSP/
SAT...MAINLY VFR. WIND SW/S 5 TO 10 KTS.
SUN...CHC MVFR-IFR/-SN. WIND SW 5-10 KTS...BECOMING NW LATE AT
25G35KT.
MON...CHC MVFR-IFR/-SN. CHC BLSN. WIND NW 25G35KT.

&&

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

$$

SHORT TERM...DWE
LONG TERM...JLT
AVIATION...BORGHOFF


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