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February 2012 General Discussion


Nic

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A lot cooler day then forecast early yesterday. Instead of high 40s, temp topped out at 35°.

MKE Lake Effect Update:

.TUESDAY - CONFIDENCE...LOW TO MEDIUM

500 MILLIBAR MID LEVEL TROUGH REMAINS TO THE NORTH WHILE SOUTHERN

STREAM WAVE PASSES JUST SOUTH OF THE AREA. QPF FROM THIS SOUTHERN

WAVE PROGGD TO STAY SOUTH THOUGH SOME UVV/700-300 MILLIBAR Q-VECTOR

CONVERGENCE NOTED INTO SRN WI. DECENT LAKE EFFECT SETUP WITH DELTA T

VALUES DROPPING TO 14-15C AND A FAVORABLE NNE FETCH. GEM-REGIONAL

HANGS ONTO THE PRECIP THE LONGEST WHILE THE NAM SHUTS THINGS DOWN

AFTER 18Z. BELIEVE THE POTENTIAL WILL LAST THE WHOLE DAY. LOOKING

AT THE NAM SOUNDING...FETCH REMAINS FAVORABLE ALL DAY WITH LAKE CAPE

NUMBERS SHOWING INVERSION HEIGHT CLOSER TO 5K. CONFIDENCE PRETTY

GOOD THAT AREAS FROM MILWAUKEE SOUTH WILL BE MOST VULNERABLE AND

WILL RAISE POPS INTO THE LIKELY CATEGORY. FLOWCHARTS TRENDING US

TOWARDS EITHER LIGHT OR MODERATE ACCUMULATIONS. DELTA T IS DECENT

WITH THE WARMER THAN NORMAL LAKE TEMPS. A PERSISTENT FETCH LOOKS TO

BE IN PLACE. WILL NUDGE AMOUNTS UP TO 3 INCHES MAX..ATTEMPTING TO

STRADDLE THE LIGHT/MODERATE THRESHOLD. MAIN FOCUS AREA SHAPING UP TO

BE FROM FAR SOUTHERN MILWAUKEE COUNTY INTO RACINE AND KENOSHA

COUNTIES. A LIMITING FACTOR COULD BE MOISTURE DEPTH NOT REACHING THE

FAVORED DENDRIDIC GROWTH REGION OF TEMPS -12C OR COLDER. CLOSE CALL

THOUGH WITH NAM SHOWING -10C BEING REACHED.

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This MJO pulse is clearly the real deal, and now appears to stand a better chance at propigating through phases 1-2 than I originally thought last week...the Euro now supports this idea:

post-525-0-10115900-1328569043.gif

With the AO also likely remaining negative or at worst becoming nuetral again, this could bode well for us shortly after mid-month:

post-525-0-91870700-1328569125.gif

Note that since the stratospheric vortex was disrupted last month, the AO forecasts from the GEFS have actually had a positive bias. Given recent trends, I expect a nuetral or a slightly negative AO to persist for much of the remaining month of February.

Although Allen's MJO phase/temperature correlation maps aren't broken down by ENSO phase or AO phase, the general look is for ridging near the west coast or over Alaska and a trough somewhere over the central/eastern CONUS in phases 8-1-2:

post-525-0-19345000-1328570291.gif

The 12z ECM ensembles at day 10 match this general look, with a large, closed low over the Aluetians and pumping up ridging near the west coast of the US, allowing polar (probably not arctic) air to be tapped and sent down into the central US. The GFS ensembles and Euro ensembles as shown below are also trying to build some sort of an east based -NAO block in the mid to long range. This could help focus cold over the central US as well:

post-525-0-14093700-1328570670.gif

All in all, after the brief cold shot coming towards the end of this week due to a displacement in the Polar Vortex, we will warm briefly but I believe the stars are lining up the best they have all winter for a favorable pattern for a notable synoptic snowstorm in the region after mid month. The storm shown just past day 10 in recent modeling may be the real deal...

I still think that even if we see troughing establish itself over the region at points during the remainder of the month that due to the scorching start in many areas and lack of snowcover over much of the CONUS that it will hard to overcome the early positive departures and that much of the region will end up near to above normal. Even so, the threat for a synoptic snow *somewhere* in the Lakes/Ohio Valley appears to be legitimate after mid month, in my opinion.

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This MJO pulse is clearly the real deal, and now appears to stand a better chance at propigating through phases 1-2 than I originally thought last week...the Euro now supports this idea:

post-525-0-10115900-1328569043.gif

With the AO also likely remaining negative or at worst becoming nuetral again, this could bode well for us shortly after mid-month:

post-525-0-91870700-1328569125.gif

Note that since the stratospheric vortex was disrupted last month, the AO forecasts from the GEFS have actually had a positive bias. Given recent trends, I expect a nuetral or a slightly negative AO to persist for much of the remaining month of February.

Although Allen's MJO phase/temperature correlation maps aren't broken down by ENSO phase or AO phase, the general look is for ridging near the west coast or over Alaska and a trough somewhere over the central/eastern CONUS in phases 8-1-2:

post-525-0-19345000-1328570291.gif

The 12z ECM ensembles at day 10 match this general look, with a large, closed low over the Aluetians and pumping up ridging near the west coast of the US, allowing polar (probably not arctic) air to be tapped and sent down into the central US. The GFS ensembles and Euro ensembles as shown below are also trying to build some sort of an east based -NAO block in the mid to long range. This could help focus cold over the central US as well:

post-525-0-14093700-1328570670.gif

All in all, after the brief cold shot coming towards the end of this week due to a displacement in the Polar Vortex, we will warm briefly but I believe the stars are lining up the best they have all winter for a favorable pattern for a notable synoptic snowstorm in the region after mid month. The storm shown just past day 10 in recent modeling may be the real deal...

I still think that even if we see troughing establish itself over the region at points during the remainder of the month that due to the scorching start in many areas and lack of snowcover over much of the CONUS that it will hard to overcome the early positive departures and that much of the region will end up near to above normal. Even so, the threat for a synoptic snow *somewhere* in the Lakes/Ohio Valley appears to be legitimate after mid month, in my opinion.

You're one of the subforum's most underrated posters.

I remain incredulous about a pattern change, but you've done your homework.

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Should be another night filled with dense fog and freezing fog across much of the Ohio Valley. The same pesky inversion is still present and the HRRR (which by the way has done VERY well with the coverage of the fog the past several nights) is indicating widespread visibilities below 1/2 of a mile after midnight across much of Iowa, Illinois, Indiana and Ohio.

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LOT Graphic for the Lake Snow

Interesting noting the direction of the lake effect between the MKX & ORD office. MKX has a more NNE direction and ORD has it coming in from the straight NE (and lesser amounts). NAM put out better ΔT values on the 18z run of 15°C.

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This MJO pulse is clearly the real deal, and now appears to stand a better chance at propigating through phases 1-2 than I originally thought last week...the Euro now supports this idea:

post-525-0-10115900-1328569043.gif

With the AO also likely remaining negative or at worst becoming nuetral again, this could bode well for us shortly after mid-month:

post-525-0-91870700-1328569125.gif

Note that since the stratospheric vortex was disrupted last month, the AO forecasts from the GEFS have actually had a positive bias. Given recent trends, I expect a nuetral or a slightly negative AO to persist for much of the remaining month of February.

Although Allen's MJO phase/temperature correlation maps aren't broken down by ENSO phase or AO phase, the general look is for ridging near the west coast or over Alaska and a trough somewhere over the central/eastern CONUS in phases 8-1-2:

post-525-0-19345000-1328570291.gif

The 12z ECM ensembles at day 10 match this general look, with a large, closed low over the Aluetians and pumping up ridging near the west coast of the US, allowing polar (probably not arctic) air to be tapped and sent down into the central US. The GFS ensembles and Euro ensembles as shown below are also trying to build some sort of an east based -NAO block in the mid to long range. This could help focus cold over the central US as well:

post-525-0-14093700-1328570670.gif

All in all, after the brief cold shot coming towards the end of this week due to a displacement in the Polar Vortex, we will warm briefly but I believe the stars are lining up the best they have all winter for a favorable pattern for a notable synoptic snowstorm in the region after mid month. The storm shown just past day 10 in recent modeling may be the real deal...

I still think that even if we see troughing establish itself over the region at points during the remainder of the month that due to the scorching start in many areas and lack of snowcover over much of the CONUS that it will hard to overcome the early positive departures and that much of the region will end up near to above normal. Even so, the threat for a synoptic snow *somewhere* in the Lakes/Ohio Valley appears to be legitimate after mid month, in my opinion.

Great post

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LES potential for tomorrow looks fairly meh.

MKX will likely end up being to bullish.

Last time they went way over board predicting 2-4" amounts. I think at most there was 0.5". Lake effect snow this coming weekend could be something to watch!

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Last time they went way over board predicting 2-4" amounts. I think at most there was 0.5". Lake effect snow this coming weekend could be something to watch!

Yeah, looks like a window of opportunity for something off of southern Lake Michigan this weekend but maybe not super long.  Thermodynamic setup appears to be better than tomorrow.

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Yeah, looks like a window of opportunity for something off of southern Lake Michigan this weekend but maybe not super long. Thermodynamic setup appears to be better than tomorrow.

I'm banking on something in the 6-10 inch range for the UP. I'm heading to the western UP Monday.

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It is funny that people are giving up on a major snow as soon as it gets cool enough for all snow events. I know angle of sun plays a role, but an event big enough to be worth watching would be able to overcome this. It looks like the MJO is moving into a favorable octave, from my amateur eyes. I think that the MJO may drive the AO NAO from what I have read around here. Forgive me if I have this wrong, I have not had the education in atmospheric science most of you have had since I am only a senior in high school.

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Thanks all...definitely looks like something to track over the next 10 days or so, with a wide array of solutions being shown:

Good lord is that a 264 hr gfs ensemble you just posted? It's February and we're pointing to a 264 hr gfs map? This is usually the type of post you see occurring in early November and everyone poking fun at.

You need no other evidence of just how bad this winter has been.

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It is funny that people are giving up on a major snow as soon as it gets cool enough for all snow events. I know angle of sun plays a role, but an event big enough to be worth watching would be able to overcome this. It looks like the MJO is moving into a favorable octave, from my amateur eyes. I think that the MJO may drive the AO NAO from what I have read around here. Forgive me if I have this wrong, I have not had the education in atmospheric science most of you have had since I am only a senior in high school.

Sun angle may play a role in how long snowcover lasts, and it also may inhibit a very light 32-34 degree snowfall from sticking much during the middle of the day, but it will not affect a true snowstorm for a while.

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BTW...I have been watching the arctic front Friday. Models have been very consistent in bringing very light qpf with the front, but last nights Euro and now the NAM want to do a little more than that with it. Certainly something to keep an eye on. I will be absolutely thrilled if I get 1"+ from this arctic front, as we have not had snow on the ground since morning of Jan 31st. (Excited about 1 inch of snow LOL, last year at this time 16 inches on the ground and unknown to me then but Ma Nature still had 4 more advisory/warning snowstorms up her sleeve yet).

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Yeah that MJO is making a wide turn there! The GFS/GEFS original forecast is holding true.

On and off light lake effect snow showers currently. 31°F. Airport is reporting Freezing Rain for some reason - it's all small snow flakes out there.

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