Area Forecast Discussion
Issued by NWS Twin Cities, MN

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000
FXUS63 KMPX 310912
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
312 AM CST SAT JAN 31 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 313 AM CST SAT JAN 31 2015

A VERY POTENT STORM SYSTEM WILL BEGIN TO ORGANIZE ACROSS THE CENTRAL
CONUS OVER THE NEXT 24-36 HRS. THE MAIN CONCERN IN MN IS WHETHER THE
MUCH DRIER AIR FROM CANADA WILL SUPPRESS THE DEEPER MOISTURE TO OUR
SOUTH...LEADING TO ONLY FLURRIES ACROSS SOUTHERN AND CENTRAL
MN...WITH THE BULK OF ANY MEASURABLE PRECIPITATION ALONG AND SOUTH
OF THE IA/MN BORDER.

ALTHOUGH SHORT TERM MODELS HAVE DONE A GOOD JOB WITH THE SPREAD OF
PRECIPITATION ACROSS KS/NE...THE COLD FRONT THAT WAS MOVING ACROSS
SOUTHERN MN EARLY THIS MORNING HAS BROUGHT MUCH DRIER AIR INTO
NORTHERN MN. REGIONAL SATELLITE IMAGERY NOTED THIS MUCH DRIER AIR
ERODING THE CLOUD COVER ACROSS THE FAR NW CORNER OF MN. USUALLY
MODELS HAVE A HARD TIME SPREADING TOO MUCH MOISTURE NORTHWARD IN
THIS TYPE OF SCENARIO WITH A COLD/DRY N/NE FLOW DEVELOPING.
ESPECIALLY CONSIDERING WIND SPDS WILL INCREASE DURING THE
AFTN/EVENING...LEADING TO FURTHER DRYING IN THE LOW LEVELS. WITH
THIS IN MIND...THERE WILL BE A VERY SHARP CUTOFF ON MEASURABLE
PRECIPITATION...TO FLURRIES AT BEST FROM SOUTH TO NORTH. CONSIDERING
QPF AMTS ALONG THE MN/IA BORDER AND THE AMT OF FORCING EXPECTED LATE
TONIGHT AND INTO SUNDAY MORNING...THERE COULD BE A PERIOD OF
MODERATE SNOWFALL ALONG THE IA/MN BORDER. CURRENT GRIDS HAVE
SNOWFALL AMTS OF 3-5 INCHES IN THE FAR SOUTHERN TIER OF MPX CWA.
THIS IS TAKING INTO ACCOUNT THE DRIER AIR AND SNOWFALL RATIOS VS.
QPF AMTS. LATER SHIFTS COULD ISSUE A WINTER WEATHER ADVISORY FOR FAR
SOUTHERN MN...BUT THE UNCERTAINTY OF THE AMT OF DRY AIR VS. FORCING
REMAINS LOW. NO OTHER CONCERNS THRU SUNDAY MORNING AS THE STORM
SYSTEM BEGINS TO MOVE OFF TO THE E/SE INTO THE OHIO VALLEY.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 313 AM CST SAT JAN 31 2015

LONG TERM FORECAST CONCERNS ARE RATHER MINIMAL...AND PRIMARILY
REVOLVE AROUND SNOWFALL CHANCES ON TUESDAY ALONG WITH THE COLD
START TO FEBRUARY.

IN THE WAKE OF THE SYSTEM ON SUNDAY...SEMI-ZONAL MID LEVEL FLOW
WILL DEVELOP INTO THE BEGINNING OF NEXT WEEK. AT THE
SURFACE...THE HIGH PRESSURE AREA OF ARCTIC ORIGIN WILL YIELD
TEMPERATURES RANGING FROM 5 TO 15 DEGREES BELOW CLIMATOLOGICAL
NORMALS.

ON MONDAY...THE AFOREMENTIONED SURFACE HIGH SLIPS OFF TO THE
SOUTHEAST AS ANOTHER CLIPPER-LIKE SYSTEM APPROACHES FROM THE
NORTHWEST. LOW LEVEL WARM AIR ADVECTION AHEAD OF THE ASSOCIATED
TROUGH WILL INITIATE A WEAK MODERATION IN TEMPERATURES ON
TUESDAY...WITH HIGHS SNEAKING CLOSER TO NORMAL...BUT STILL
SLIGHTLY BELOW WITH READINGS RANGING FROM AROUND 20 TO 25
DEGREES. WHILE WE COULD SEE SNOW DEVELOP AS EARLY AS MONDAY
EVENING AS A WEAK POTENTIAL VORTICITY ELEMENT PASSES OVER...THE
BETTER FORCING AND MOISTURE ADVECTION ARRIVE AS THE TROUGH PASSES
ON TUESDAY. ACCUMULATIONS IN THE HALF INCH TO 2 INCH RANGE APPEAR
APPROPRIATE.

AFTER TUESDAY...THE REMAINDER OF THE WORK WEEK LOOKS TO BE DRY
OVERALL...WITH TEMPERATURES WARMING BACK TO NEAR OR ABOVE NORMAL
VALUES FOR NEXT WEEKEND.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1129 PM CST FRI JAN 30 2015

CURRENT MVFR CIGS ON TRACK TO SPREAD S/SE ACROSS MPX CWA BY
12Z. THERE MAY BE A DELAY OF AN HR OR TWO IN THE SOUTHERN PART OF
MPX CWA...BUT STILL HAVE HIGH CONFIDENCE OF THE CONTINUED TREND.
UPSTREAM ACROSS SOUTH CENTRAL CANADA...STRONG EVIDENTS OF DRIER
AIR MOVING SOUTHWARD WHICH MEANS THE MVFR CIGS WILL LIKELY BEGIN
TO BREAK UP OR DISSIPATE BY MID/LATE MORNING ACROSS CENTRAL
MN. HOW FAR SOUTH THE DRIER AIR WILL SPREAD IS THE MAIN
CONCERN...ESPECIALLY FOR KRWF/KEAU WHERE MVFR MAY CONTINUE THRU
THE TAF PERIOD. THE WORSE CONDS WILL OCCUR AFT 06Z/01...BUT ENOUGH
CONFIDENCE TO INTRODUCE -SN AT KRWF BY 3Z. WINDS WILL SHIFT TO THE
N/NE TODAY WITH GUSTY WINDS DEVELOPING SATURDAY AFTN/EVENING FROM
THE NE.

KMSP...

HIGH CONFIDENCE OF VFR CONDS THRU 12Z...WITH CIGS LOWERING TO MVFR
BY 12-14Z. TIMING IS THE MAIN ISSUE BUT CURRENT TRENDS SEEM
REASONABLE OF VFR THRU 12Z. MVFR CIGS MAY CONTINUE THRU THE AFTN
BEFORE DRIER AIR FILTERS IN FROM THE N/NE. CONFIDENCE REMAINS LOW
ON WHEN THE MVFR CIGS DISSIPATE OR CONTINUE BASED ON THE STRENGTH
OF THE DRIER AIR. HAVE INTRODUCED -SN AFT 9Z AS A STORM SYSTEM
ACROSS THE PLAINS BRUSHES THE SOUTHERN PART OF MPX CWA. WINDS WILL
SHIFT TO THE NORTH BY 10-12Z...THEN MORE NE AND INCREASING DURING
THE AFTN/EVENING WITH GUSTY WINDS.

/OUTLOOK FOR KMSP/

SUN...MVFR CIGS/VSBYS EARLY WITH -SN. NORTH WIND 10 TO 15 KT.
SUN NIGHT...VFR. NORTH WIND BECOMING SW 5-10 KT.
MON...VFR. SOUTHWEST WIND 5 TO 10 KT.
MON NIGHT...MVFR CEILINGS POSSIBLE. SOUTHWEST WIND 5 TO 10 KT.
TUE...MVFR CIGS/VSBYS IN -SN POSSIBLY IFR AT TIMES. WIND BECOMING
NORTH AROUND 10 KT.


&&

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

$$

SHORT TERM...JLT
LONG TERM...LS
AVIATION...JLT


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