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Possible winter storm March 1st-2nd


Thundersnow12

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For whatever reason the models are having a hell of a time figuring this storm out.  I've seen them in better agreement on a storm 50+hrs out than this.  Just goes to show that guidance still has some major improving to do in the future, as there's certain complexities they still can't deal with.  

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For whatever reason the models are having a hell of a time figuring this storm out.  I've seen them in better agreement on a storm 50+hrs out than this.  Just goes to show that guidance still has some major improving to do in the future, as there's certain complexities they still can't deal with.  

 

Adds some drama though...would get boring if there were perfect progs.

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If I didn't know better I would've thought we transported back in time to 2012; decent looking shot at a storm first two days of March followed by the looks of a big torch.

 

that was a ho-hum terrible winter here also..  leap yr to with a big up north storm on the 29th.. hot summer and drought.. we did have a couple run-ups with severe stuff in july if i remember right.  its all lining up

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Can't say IWX didn't communicate the uncertainty

 


SHORT TERM  (THIS EVENING THROUGH TUESDAY NIGHT)   ISSUED AT 340 PM EST SUN FEB 28 2016     ..TONIGHT THROUGH TUESDAY NIGHT    COMPLICATED AND ACTIVE SHORT TERM PERIOD. SHORT WAVE WITH MODEST  MOISTURE ADVECTION AND ASCENT TO MOVE ACROSS THE REGION THIS  EVENING. MODELS IN GOOD AGREEMENT WITH LIGHT RAIN SHOWERS  EXPANDING AHEAD OF SFC FRONT AS IT CROSSES OUR REGION. RUC AND  HRRR HAVE CONSISTENTLY SHOWED LIGHT PCPN DEVELOPING OVER WEST  CENTRAL AREA AND EXPANDING EASTWARD. WENT WITH HIGHER CONSRAW POPS  GIVEN MOS AND HIRES TRENDS.    FOCUS QUICKLY TURNS TO SYSTEM FROM MONDAY NIGHT INTO TUESDAY NIGHT.  COMPLICATED UPPER AIR PATTERN WREAKING HAVOC ON DETERMINISTIC MODEL  SOLUTIONS FOR THIS SYSTEM. WHILE SOME CONSENSUS HAS BEEN REACHED  AMONG MODELS ON BASIC SYNOPTIC EVOLUTION...MANY DIFFERENCES  CONTINUE BETWEEN MODELS AND STILL WITHIN EACH INDIVIDUAL MODELS  RUN TO RUN CONTINUITY DESPITE BEING WITHIN 48 HOURS OF PCPN ONSET.  MOST OF THIS DISPARITY COMES FROM FACT THAT MAIN JET ENERGY  REMAINS OFF THE WEST COAST TODAY AND WILL NOT BE SAMPLED FULLY  UNTIL MONDAY MORNING MOST LIKELY. THIS ENERGY WILL BE INTERACTING  WITH A STRONG SHORT WAVE DIVING SOUTH THEN EAST OUT OF THE ARCTIC  CIRCLE. THE DEGREE OF PHASING AND INTERACTION OF THESE WAVES IS  PROVING PROBLEMATIC FOR ALL MODELS. WEAKLY COUPLED UPPER JET WILL  LEAD TO SFC LOW DEVELOPMENT OVER THE CENTRAL CONUS AND THE TRACK  OF THIS LOW AND ITS DEVELOPMENT REMAINS AN ISSUE AMONG MODELS.    NORTHERN STREAM SHORT WAVE TO PUSH A SFC COLD FRONT THROUGH FROM  NORTH TO SOUTH MONDAY NIGHT. THIS WILL ALLOW SFC TEMPS TO FALL INTO  THE 20S NORTH AND LOW TO MID 30S SOUTH. WARM AIR ADVECTION ALOFT  DEVELOPS QUICKLY MONDAY NIGHT AS BAROCLINIC ZONE SETS UP OVER  NORTHERN AREAS. FGEN FORCING WITH THIS ADVECTION PROCESS WILL LEAD  TO EXPANDING AREA OF PRECIPITATION...LIKELY ALL SNOW ACROSS THE  NORTH TO BEGIN. AS SFC LOW DEVELOPS AND TRACKS EAST  TUESDAY...PRECIPITATION WILL BECOME HEAVIER. COMBINATION OF SFC  TEMPS BELOW FREEZING AND 850MB TEMPS ABOVE 0C WILL LEAD TO AREA OF  FREEZING RAIN SOMEWHERE OVER THE AREA. 12Z SUITE HAVE TRENDED A BIT  FURTHER NORTH WITH SFC LOW TRACK AND ARE ONCE AGAIN ADVERTISING A  STRONG WARM SURGE THROUGH MOST OF OUR AREA TUESDAY. GEM AND ECMWF  ARE STRONGER WITH COLDER AIR COMING IN FASTER TUESDAY. THESE LATTER  MODELS ARE GENERALLY PREFERRED BUT THEY ARE ALSO INDICATING A PERIOD  OF MIXED/FREEZING PRECIPITATION EARLY TUESDAY.     THIS FORECAST PACKAGE USED A BLEND OF PREVIOUS FORECAST WITH SOME OF  THE LATEST 12Z GUIDANCE TO GET MORE MIXED PRECIPITATION ACROSS  CENTRAL AND NORTHERN AREAS. UNCERTAINTY REMAINS HIGH AND FULLY  EXPECT ADDITIONAL SIGNIFICANT CHANGES IN MODELS GIVEN COMPLEX UPPER  AIR PATTERN AND INTERACTIONS. STILL RETAINED ADVISORY LEVEL SNOW  ACCUMS IN THE FAR NORTH WITH LESS SNOW ACCUMS CENTRAL AND SOUTH WITH  MORE MIXED PRECIPITATION. LIGHT ICE ACCUMULATIONS ARE EXPECTED AND  DEPENDING ON FINAL TRACK AND THERMAL FIELDS A NARROW RIBBON OF ICE  ACCUMS COULD COME CLOSE TO 0.20-0.25 INCHES. AGAIN...LOTS OF  UNCERTAINTY BUT SOME TYPE OF HEADLINES LOOK LIKELY GIVEN MIXED  PRECIPITATION.    PRECIPITATION TO CHANGE OVER TO SNOW TUESDAY NIGHT ALL AREAS BEFORE  ENDING. ADDITIONAL ACCUMS THIS PERIOD REMAIN MURKY GIVEN MODEL  DISPARITY BUT HIGHEST AMOUNTS SHOULD BE IN THE EAST WITH WRAP  AROUND AS SYSTEM DEPARTS.     STAY TUNED TO FORECASTS TONIGHT AND MONDAY.    
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dProg/dT of the NAM shows it initialized that rear shortwave stronger, which goes on to produce that deeper solution (much deeper and neg tilt aloft). The 18z run is contaminated with convective feedback and doesn't have nearly enough cold sector precip (as did the 12Z GFS), so it's still a grain of salt solution as far as low track and QPF go.

 

There should also be a lake plume Tuesday that will locally enhance snowfall. This air mass north of the border means business.

 

The players on the field suggest to me there is the potential for someone to pick up 12"+ out of this storm, wherever tomorrow night's fronto band coincides with Tuesday's defo band. 

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I wouldn't put a lot of stock in the NAM right now. It's not in its ok range yet.

 

The low jumping around MO and IA is goofy.

 

 

 

When the NAM is a serious outlier I tend to write it off and just await for it to adjust back to other guidance.. but dang this is really getting down to where it should at least stop widening the gap between it and the euro.

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NAM frontogenesis fields look really nice.  If anyone remembers back to the Nov 21 storm, that band went to town and greatly overperformed in far northern IL/southern WI and helped contribute to that narrow area of really high storm totals.  Wherever it sets up tomorrow night hopefully is in for something good.

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That shortwave was barely sampled at all - more importantly, the vort behind it is very poorly initialized by all guidance (too weak), including 12z coming in. That's telling me the backside jet is coming in stronger and will help this dig more, with the southern wave possibly trending faster and deeper in subsequent guidance. If correct, that suggests some of the negative tilt/beefed up runs from a few days ago may be closer to reality. Will be interesting to see 12z ensembles. 

 

DTX at least seems to disagree with the bolded, respectfully...

 

 

ATTENTION THEN TURNS TO WHAT WITH BE A MORE SIFIGNICANT STORM SYSTEM

DUE INTO THE AREA TUESDAY AND TUESDAY NIGHT AS A STRONG SHORTWAVE NOW

JUST OFF THE BRITISH COLUMBIA/WASHINGTON COAST DIGS INTO MEAN UPPER

LEVEL TROUGH OVER CENTRAL/EASTERN NOAM AND PHASES WITH ANOTHER

VIGOROUS ARCTIC SHORTWAVE PIVOTING SOUTH/SOUTHEAST THROUGH CENTRAL

CANADA AROUND WEST SIDE OF POLAR VORTEX CENTERED OVER HUDSON BAY.

NOW THAT THESE SHORTWAVES HAVE BEEN SAMPLED TO A LARGER DEGREE...12Z

MODEL RUNS HAVE PERHAPS BEGUN TO CONVERGE ON A RELATIVELY STABLE

SOLUTION...AT LEAST COMPARED TO THE CHAOTIC MODEL TO MODEL AND RUN

TO RUN FORECASTS OF THE PAST SEVERAL DAYS REGARDING THIS POTENTIAL

SYSTEM. GEM/GFS/NAM...AND TO A LESSER DEGREE UKMET...HAVE TRENDED TO

A MORE PHASED AND THUS STRONGER SOLUTION FOR THE RESULTANT LOW

PRESSURE THAT LIFTS EAST NORTHEAST THROUGH THE OHIO VALLEY. THE

PHASING ALSO OCCURS FURTHER WEST AND SLOWS THE MAIN SYSTEM/S

ARRIVAL SLIGHTLY...WHILE LEADING TO A TRACK NORTH OF THE ROUGH 00Z

MODEL CONSENSUS. GIVEN THE DEGREE OF AMPLITUDE OF THE MEAN WESTERN

NOAM RIDGE...THIS SOLUTION MAKES MORE SENSE AS THE SHORTWAVE WITHIN

THE ARCTIC STORM TRACK WOULD SHOULD BE MORE LIKELY TO DIG MORE

SHARPLY SOUTHWARD INTO THE CONUS PLAINS AND LEAD TO THIS GREATER

PHASING AS THE WAVES INTERACT OVER THE PLAINS/MIDWEST.

SUCH A SOLUTION WOULD BRING ANOTHER FORMIDABLE WINTER STORM THROUGH

THE SOUTHERN GREAT LAKES...WITH A LARGE SWATH OF SIGNIFICANT SNOW

ACCUMULATIONS ONCE AGAIN POSSIBLE. IN ADDITION...WITH A LARGER POOL

OF ARCTIC AIR NEARBY IN THE WAKE OF THE AFOREMENTIONED CLIPPER

SYSTEMS...THE POSSIBLY OF SLEET/FREEZING RAIN WILL BE HIGHER WITH

THIS STORM...DEPENDING ON THE NORTH TO SOUTH ORIENTATION OF THE

EVENTUAL LOW TRACK TUESDAY INTO TUESDAY NIGHT.

WHILE CONFIDENCE HAS INCREASED FOR A STRONGER STORM SYSTEM AFFECTING

THE AREA...THE JUMPY MODEL SOLUTIONS TO THIS POINT CANNOT BE

DISCOUNTED ENTIRELY JUST YET. GFS ENSEMBLE MEMBERS...WHILE WEIGHTED

TO A STRONGER SYSTEM AS WELL...VARY ENOUGH TO BRING SIGNIFICANT

DOUBT TO THE EXACT LOW TRACK AND PRECIPITATION TYPE DISTRIBUTION.

WILL NOT MAKE ANY LARGE CHANGES TO THIS FORECAST...BUT WILL TREND TO

A GREATER CHANCE OF PRECIPITATION AND INCLUDE A MENTION OF A WINTRY

MIX FOR PARTS OF THE SOUTHERN FORECAST AREA. PRECIPITATION BEGINS

WITH FGEN FORCING ALONG STALLED WEST TO EAST FRONT MONDAY NIGHT

INTO EARLY TUESDAY AS THIS LOW ORGANIZES AND APPROACHES FROM THE

WEST...AND THEN TRANSTION AN AREA DEFORMATION PRECIPITATION AS THE

SYSTEM LIFTS INTO THE OHIO VALLEY/GREAT LAKES LATE TUESDAY INTO

TUESDAY NIGHT.

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NAM frontogenesis fields look really nice.  If anyone remembers back to the Nov 21 storm, that band went to town and greatly overperformed in far northern IL/southern WI and helped contribute to that narrow area of really high storm totals.  Wherever it sets up tomorrow night hopefully is in for something good.

 

Given the decent temp gradient and what looks to be excellent low level convergence (both more impressive than what we had during Nov. 21st), there's definitely solid potential for that band to overachieve.

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dProg/dT of the NAM shows it initialized that rear shortwave stronger, which goes on to produce that deeper solution (much deeper and neg tilt aloft). The 18z run is contaminated with convective feedback and doesn't have nearly enough cold sector precip (as did the 12Z GFS), so it's still a grain of salt solution as far as low track and QPF go.

 

There should also be a lake plume Tuesday that will locally enhance snowfall. This air mass north of the border means business.

 

The players on the field suggest to me there is the potential for someone to pick up 12"+ out of this storm, wherever tomorrow night's fronto band coincides with Tuesday's defo band. 

 

Well said. Thanks for your thoughts.  :clap:

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EPS control mean is from just southwest of Terre Haute to Dayton about.

GEFS members.

Some big dogs in there!

 

post-46-0-30120600-1456692917.png

Wow, that's quite the range of solutions. Definitely are some big dogs in there.  e17 gives parts of far northern IN/southern MI over 2 feet and me nothing in southern WI. Some of the others are opposite of that.

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greenbay likes snow over rain for chicago. not shocking by any means

LONG TERM  MONDAY NIGHT THROUGH SUNDAY  ISSUED AT 304 PM CST SUN FEB 28 2016    SIGNIFICANT WINTER STORM LOOKS LIKELY TO STAY JUST SOUTH OF OUR  FORECAST AREA TUESDAY AS A COUPLED JET HELPS INDUCE CYCLOGENESIS  ACROSS SOUTHERN ILLINOIS. MILWAUKEE AND NORTHERN ILLINOIS SHOULD  GET A GOOD SNOW OUT OF THIS.
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