452 
FXUS63 KMPX 291830
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1230 PM CST WED JAN 29 2014

.UPDATE...

18Z AVIATION DISCUSSION ADDED BELOW.

&&

.SHORT TERM...(TODAY THROUGH THURSDAY) 
ISSUED AT 406 AM CST WED JAN 29 2014

MAIN CONCERN IN THE SLIGHTLY EXTENDED SHORT TERM PERIOD IS SNOW 
MOVING IN LATE TONIGHT INTO THURSDAY MORNING...WHICH IS STARTING TO 
LOOK A LITTLE BIT MORE ROBUST. OUR PRIMARY SUSPECT IN THIS CASE CAN 
BE SEEN IN WATER VAPOR IMAGERY AND RAP H4-H3 PV ANALYSIS ROUNDING 
THE TOP OF THE WEST COAST RIDGE AND COMING ONSHORE ALONG THE WASH/BC 
BORDER THIS MORNING. 00Z MODELS HAVE COME IN IN PRETTY GOOD 
AGREEMENT ON THIS FEATURE...WITH THE MAIN DISAGREEMENT SURROUNDING 
AROUND JUST HOW MUCH PRECIP FALLS WITHIN THE HEAVIEST PART OF THE 
PRECIP SHIELD.

AS FOR THE FORCING WITH THIS WAVE...MODELS SIMILAR WITH SHOWING THE 
WASH/BC PV FEATURE MOVING ACROSS SRN MN THURSDAY MORNING ON THE 
POLEWARD SIDE OF A 150 KT UPPER JET STREAK HEADING FOR IOWA...SO WE 
WILL BE ADDING LEFT EXIT DYNAMICS TO GO ALONG WITH THE PV FORCING. 
AT THE SFC...THE ARCTIC BOUNDARY THAT IS CURRENTLY MOVING SOUTH 
ACROSS ALBERTA WILL HAVE FOUND ITS WAY INTO NRN IOWA AND UP INTO THE 
CENTRAL U.P. OF MICH BY THURSDAY MORNING. AS THE UPPER FORCING 
CATCHES UP WITH THE SFC BOUNDARY...WE SEE A GOOD AREA OF LIFT 
BLOSSOM ALONG THE 295K THETA AS WARM AIR GETS PULLED UP AND OVER THE 
ARCTIC BOUNDARY. THE 295K SFC SHOWS LIGHT SNOW FALLING ACROSS JUST 
ABOUT THE ENTIRE CWA...BUT THE BEST FORCING IS CENTERED DOWN ALONG 
THE IA BORDER BETWEEN ABOUT 12Z AND 15Z. THIS IS ALSO COINCIDENT 
WITH WHERE THE PV FEATURE WILL BE MOVING ACROSS. TO NO SURPRISE... 
SRN MN...BETWEEN ABOUT ST. PETER AND THE IA BORDER IS WHERE ALL 
MODELS SHOW THE MOST QPF FALLING. ALL GUIDANCE SHOWS AT LEAST A 
QUARTER INCH OF QPF FALLING DOWN THERE...WHICH WOULD TRANSLATE TO 
ABOUT 3 INCHES OF SNOW...BUT SOME OF THE HI-RES MODELS AND 
INDIVIDUAL SREF MEMBERS SHOW OVER A HALF INCH OF QPF FALLING IN THIS 
AREA AS WELL...WHICH WOULD INDICATE THE POTENTIAL FOR SOME 
BORDERLINE WARNING SNOWS /6 INCHES/ DOWN IN SOUTH CENTRAL MN. IN 
FACT...THE PROBABILITIES FOR OVER 4 INCHES OF SNOW WITH THE 29.03 
SREF IS UP OVER 60 PERCENT DOWN BETWEEN ST. PETER AND IA. WHAT WAS 
DONE WITH THIS FORECAST PACKAGE WAS TO BOOST POPS EVERYWHERE LATE 
TONIGHT THROUGH THURSDAY MORNING AND USED A BLEND OF THE 
DETERMINISTIC MODELS FOR QPF. THIS RESULTED AROUND 3 INCHES OF SNOW 
DOWN IN SRN MN...WITH AROUND 2 INCHES UP IN THE METRO THAT WILL FALL 
DURING THE MORNING RUSH ON THURSDAY. ALTHOUGH THIS WILL CERTAINLY 
SLOW THE MORNING COMMUTE...I THINK IT IS FAIR TO SAY THAT 2 INCHES 
OF SNOW DURING THE MORNING RUSH HERE WILL NOT CAUSE AS MANY PROBLEMS 
AS THE 2 INCHES OF SNOW FOR THE EVENING RUSH IN ATLANTA DID 
YESTERDAY.

WE DID HAVE SOME HEALTHY DISCUSSION THIS MORNING WITH DMX AND ARX 
ABOUT ISSUING AN ADVY FOR THIS EVENT FOR A FEW REASONS. NUMBER 
ONE...TIMING WISE THIS WILL IMPACT MORNING DRIVES INTO WORK/SCHOOL. 
IN ADDITION...IF WE DO END UP SEEING SNOWFALL TOTALS UP CLOSER TO 
THE 5 INCH MARK...THEN THAT MEANS WE WOULD BE SEEING SNOWFALL RATES 
UP BETWEEN 1 AND 2 INCHES AN HOUR. FINALLY...ON THE BACK END OF THE 
SNOW THURSDAY AFTERNOON...GUSTY NW WILL RETURN IN THE WAKE OF THE 
COLD FRONT...MEANING THERE WILL BE SOME BLOWING AND DRIFTING 
CONCERNS AS WELL. STILL LOTS OF UNCERTAINTIES THOUGH AS TO JUST HOW 
MUCH QPF AND THEREFORE SNOW THIS WILL PRODUCE...AS A RESULT WE 
DECIDED THAT THERE WAS ENOUGH TIME WITH THIS UNCERTAINTY ON SNOWFALL 
AMOUNTS TO LET THE NEXT SHIFT GET ONE MORE LOOK AT MODEL RUNS BEFORE 
DECIDING ON ANY HEADLINES.

.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 406 AM CST WED JAN 29 2014

PAST THURSDAY/S SYSTEM...THE MEAN UPPER LEVEL PATTERN CHGS SOME. THE 
MAIN CHG IS THE UPPER TROUGH MOVES FURTHER TO THE WEST WITH A MORE 
POSITIVE TILT TROUGH FOR MOST OF NORTH AMERICA FROM THE ROCKIES TO 
THE EAST COAST THROUGH THE FIRST WEEK OF FEBRUARY. THIS WOULD KEEP 
THE COLD PATTERN CONTINUING ACROSS THE UPPER MIDWEST. THERE IS 
ANOTHER CHG RELATED TO THE UPPER JET WHICH HAS A MORE PRONOUNCED 
SOUTHERN JET COMPARED TO A SPLIT FLOW REGIME. THIS WOULD KEEP OUR 
REGION QUIET. ALTHOUGH TWO WEAK FRONTAL BOUNDARIES DO MOVE ACROSS 
THE UPPER MIDWEST THIS WEEKEND...AND AGAIN NEXT WEEK...THIS IS 
MAINLY REINFORCING SHOTS OF COLD AIR. AS PER THE STRONGER SOUTHERN 
JET TAKING PLACE THIS WEEKEND...AND INTO NEXT WEEK...MOST OF THE 
ACTIVE WX WILL REMAIN SOUTH OF THE UPPER MIDWEST.

LOOKING AT NORMALIZED ANOMALY EXTREMES OFF THE GEFS FOR 92/85/70H 
TEMPS...NO BIG COLD OUTBREAKS EXPECTED WITH ONLY THE TEMPORARY TEENS 
TO SINGLE DIGITS BLW ZERO FOR OVERNIGHT LOWS...AND HIGHS IN THE 
SINGLE DIGITS TO THE TEENS ABV ZERO. THIS IS STILL WELL BLW 
NORMAL...BUT NOT AS EXTREME AS IN THE PREVIOUS WEEKS. IF YOU COMPARE 
THESE EXTREME ANOMALIES FOR THE FIRST WEEK OF JANUARY WHERE TEMPS 
FELL TO -23 AT MSP...THESE EXTREME VALUES WERE 3 TO 4 STANDARD 
DEVIATIONS BLW NORMAL. NEXT WEEK THESE EXTREME VALUES ARE 1 TO 2 
STANDARD DEVIATIONS BLW NORMAL.  

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1218 PM CST WED JAN 29 2014

VFR CIGS WILL DOMINATE THIS AFTERNOON AND INTO TONIGHT AS
INCREASING MID/HIGH CLOUDS BUILD IN...AND SOUTHWEST WINDS STILL
REMAIN ON TRACK TO BEGIN GUSTING THIS AFTERNOON. TEMPERATURES HAVE
QUICKLY CLIMBED AS EXPECTED...AND WILL TOP OUT IN THE 20S TO LOWER
30S ACROSS THE FA THIS AFTERNOON. FOR THE OVERNIGHT INTO
THURSDAY...A QUICK BURST OF ACCUMULATING SNOW WILL MOVE ACROSS THE
AREA...MOST HEAVILY IMPACTING THE TC METRO AND AREAS SOUTH TO THE
IOWA BORDER. TERMINALS IN THIS REGION CAN GENERALLY EXPECT 2-4
INCHES OF SNOW...PRIMARILY COMING BETWEEN 12Z AND 18Z TOMORROW.
CIGS WILL LIKELY TO DROP TO LIFR FOR A PORTION OF THIS TIME
PERIOD. STC AND AXN REMAIN A LITTLE TOO FAR NORTH TO BE AS HEAVILY
IMPACTED...AND WILL SEE LIGHTER ACCUMULATIONS AND BETTER OVERALL
CIGS. WINDS DECREASE THIS EVENING IN THE VICINITY OF THE INCOMING
FRONT. THE SNOW WILL END BY ABOUT MIDDAY THURSDAY AND VFR CIGS
WILL QUICKLY RETURN UNDER CAA AND CLEARING SKIES WITH BLUSTERY NW WINDS.

KMSP...1230Z TO 1500Z LOOKS TO BE LIFR WITH MOST OF THE SNOW
ACCUMULATION OCCURRING DURING THIS PERIOD. BETTER MODEL AGREEMENT
TODAY HAS INCREASED OUR CONFIDENCE IN THE INTENSITY AND TIMING
OF THIS INCOMING SNOW. DO EXPECT THE CEILINGS TO DROP DOWN TO
BELOW 1K FT DURING THIS PERIOD. TOMORROW AFTN WILL SEE MAJOR
IMPROVEMENT WITH STRONG NW WINDS.

/OUTLOOK FOR KMSP/
THU NIGHT...VFR. WINDS NW AT 10-15KTS. TURNING COLD.
FRI...VFR. WINDS WSW 5 KTS. 
SAT...VFR. WINDS SW 5KTS EARLY BCMG NW AT 10G15KTS.



&&

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

$$

SHORT TERM...MPG 
LONG TERM...JLT 
AVIATION...SPD