Area Forecast Discussion
Issued by NWS Twin Cities, MN

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000
FXUS63 KMPX 311134
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
534 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 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 519 AM CST SAT JAN 31 2015

MVFR/IFR CIGS CONTINUED TO SPREAD SOUTHWARD ACROSS MN EARLY THIS
MORNING. THE BACK EDGE OF THE LOWER CIGS WERE MOVING ACROSS NW/WC
MN WHICH SHOULD BEGIN TO CLEAR LOWER CIGS OUT IN KAXN BY 14-16Z.
ELSEWHERE...SKIES WILL CLEAR FROM NORTH TO SOUTH...BUT THE
SOUTHWARD EXTENT REMAINS QUESTIONABLE BASED ON THE AMT OF DRIER
AIR AND RETURN FLOW ACROSS FAR SOUTHERN MN DURING THE
AFTN/EVENING.

KEPT TAFS CLOSE TO PREVIOUS ONES WITH KSTC BREAKING OUT ARND
18-20Z...AND NEAR KRNH BY 20-22Z. LATEST MODEL DERIVED
REFLECTIVITY HAS THE NORTHERN EXTENT OF THE HIGHER RETURNS MOVING
INTO FAR SOUTHERN MN AFT 21Z...AND NEAR KDXX TO KMSP-KEAU BY 3-6Z.
THE NORTHERN EXTENT OF THIS DERIVED REFLECTIVITY PATTERN REMAINS
QUESTIONABLE DUE TO THE VERY DRY LOW LEVEL FLOW
CONTINUING/STRENGTHENING DURING THE AFTN/EVENING. CONFIDENCE
REMAINS LOW ON HOW FAR IFR/MVFR CIGS/VSBYS IN SNOW OCCUR...NORTH
OF THE MINNESOTA RIVER VALLEY. WINDS WILL INCREASE FROM THE NE
LATER TODAY AND GUST DURING THE OVERNIGHT PERIOD.

KMSP...

KEPT MVFR CIGS THRU 22Z BASED ON UPSTREAM OBS AND CURRENT LOW
LEVEL MOISTURE. THERE COULD BE A SHORT PERIOD OF CIGS OF 1.5K THRU
15Z BEFORE CIGS SLOWLY LIFT. HOWEVER...CONFIDENCE REMAINS LOW
ENOUGH FOR ONLY A TEMPORARY PERIOD. LATER THIS EVENING...THE
NORTHERN EXTENT OF THE -SN SHOULD MOVE AS CLOSE AS THE SOUTHERN
SUBURBS...BUT DO NOT EXPECTED IFR IN -SN AT THIS TIME. WINDS WILL
BECOME MORE NE THIS AFTN AND BEGIN TO GUST.

/OUTLOOK FOR KMSP/

SUN NIGHT...VFR. NORTH WIND BECOMING SW 5-10 KT.
MON...VFR. SOUTHWEST WIND 5 TO 10 KT.
MON NIGHT...MVFR CIGS 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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