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January Pattern and Storm Discussion II


Cold Rain

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I just looked at the 00z euro and 6z gfs. I don't see a mechanism to lock in the cold. It seems transient from what I'm seeing.

 

I think it's safe to say right now that 6z is an outlier for both next weekends storm and the LR. As for the 00z Euro I would say this is a good enough mechanism.  Weird for some reason Allan's site was showing the Euro indices for like Jan 5th. 

 

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http://www.daculaweather.com/4_hpc_extended_disco.php

 



 

EXTENDED FORECAST DISCUSSIONNWS HYDROMETEOROLOGICAL PREDICTION CENTER COLLEGE PARK MD1245 AM EST SUN JAN 13 2013VALID 12Z WED JAN 16 2013 - 12Z SUN JAN 20 2013THE HPC MEDIUM RANGE FORECAST REMAINS STEADFAST DESPITE THE MANYOFF-KEY VOICES FROM THE PEANUT GALLERY OF DETERMINISTIC MODELS.

 

A COLD/DRY AIRMASS SHOULD OVERTAKEMUCH OF THE CONUS EAST OF THE DIVIDE AND NORTH OF THE GULF ASANOTHER NORTHERN SHORTWAVE TUGS THE CANADIAN VORTEX TOWARD THEGREAT LAKES. BOTH THE GFS AND ECMWF INDICATE THIS SECOND SURGETHROUGH CANADA THOUGH WITH SOME EXPECTED DIFFERENCES. IF NOTHINGELSE... IT WILL AT LEAST FEEL MORE LIKE WINTER IN THE EAST THOUGHQPF POTENTIAL WILL BE LIMITED TO THE NORTHER PLAINS/GREAT LAKESAND SOUTHEAST/FLORIDA.
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Ya'll realize that posting those snow maps is bogus. If you look at the skew t you'll realize that none of that snow over alabama or tennessee actually exists on the model.

 

But carry on with the weeniedom.

 

You are missing the point. If it is showing up then it is not too far off as a possibility. People never fail to keep taking everything verbatim. This is a discussion, not a no it won't happen.

 

 

...LOWER MS/TN VLYS...A POSITIVE TILTED UPPER TROUGH STRETCHING FROM THE UPPER MIDWESTTO THE SOUTHWEST AND A SERN UPPER RIDGE WILL SETUP THE UPPER-LEVELPATTERN OVER THE ERN 2/3 OF THE COUNTRY FOR TUES. MEANWHILE AT THESURFACE... A QUASI-STATIONARY FRONT WILL STRETCH FROM THE MID-ATLSTATES TO THE DEEP SOUTH/WRN GULF OF MEXICO WITH A COLD EXPANSIVEPOLAR/ARCTIC RIDGE TO THE NORTH AND WEST OF THIS BOUNDARY. A QUICKIMPULSE ALOFT WILL RIDE THE SWRLY PROGRESSIVE FLOW ALOFT AND ALLOWAN INFLUX OF MOISTURE TO SURGE NORTH FROM THE GULF. SOME OF THISMOISTURE COULD OVERRUN INTO THE SHALLOW AIR MASS BUT MAINLY REMAINALONG THE FRONT/WARM SECTOR... DUE TO THE LACK OF A SIGNIFICANTSURFACE WAVE. THUS SOME LIGHT ICING WILL BE POSSIBLE FROM NRNLA/SERN AR TO WRN/CENTRAL TN BUT THE AMOUNTS SHOULD NOT BEANYWHERE NEAR .25 INCH AMOUNTS. HOWEVER... ANY FROZEN PRECIP FORTHIS AREA OF THE COUNTRY IS A SIGNIFICANT DEAL AND A LOW PROB OF.25 ICING WILL BE PLACED OVER THE REGION FOR MON. HPC FOLLOWED THEGFS AND ECMWF THROUGHOUT THIS 24 HRS FCST PERIOD.
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You are missing the point. If it is showing up then it is not too far off as a possibility. People never fail to keep taking everything verbatim. This is a discussion, not a no it won't happen.

 

 

...LOWER MS/TN VLYS...A POSITIVE TILTED UPPER TROUGH STRETCHING FROM THE UPPER MIDWESTTO THE SOUTHWEST AND A SERN UPPER RIDGE WILL SETUP THE UPPER-LEVELPATTERN OVER THE ERN 2/3 OF THE COUNTRY FOR TUES. MEANWHILE AT THESURFACE... A QUASI-STATIONARY FRONT WILL STRETCH FROM THE MID-ATLSTATES TO THE DEEP SOUTH/WRN GULF OF MEXICO WITH A COLD EXPANSIVEPOLAR/ARCTIC RIDGE TO THE NORTH AND WEST OF THIS BOUNDARY. A QUICKIMPULSE ALOFT WILL RIDE THE SWRLY PROGRESSIVE FLOW ALOFT AND ALLOWAN INFLUX OF MOISTURE TO SURGE NORTH FROM THE GULF. SOME OF THISMOISTURE COULD OVERRUN INTO THE SHALLOW AIR MASS BUT MAINLY REMAINALONG THE FRONT/WARM SECTOR... DUE TO THE LACK OF A SIGNIFICANTSURFACE WAVE. THUS SOME LIGHT ICING WILL BE POSSIBLE FROM NRNLA/SERN AR TO WRN/CENTRAL TN BUT THE AMOUNTS SHOULD NOT BEANYWHERE NEAR .25 INCH AMOUNTS. HOWEVER... ANY FROZEN PRECIP FORTHIS AREA OF THE COUNTRY IS A SIGNIFICANT DEAL AND A LOW PROB OF.25 ICING WILL BE PLACED OVER THE REGION FOR MON. HPC FOLLOWED THEGFS AND ECMWF THROUGHOUT THIS 24 HRS FCST PERIOD.

 

 

Uh...the AFD you posted has nothing to do with the snow map you posted. Those are two different storms.  Sorry didn't realize you posted that first map.

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Uh...the AFD you posted has nothing to do with the snow map you posted. Those are two different storms.  Sorry didn't realize you posted that first map.

 

To Wilkesborodude's credit:  he originally posted two maps (they've since been removed, apparently).  One was 48 hours out and one was 160ish out.  So, the AFD does apply to his first map that was showing snow/ice over TN.

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To Wilkesborodude's credit:  he originally posted two maps (they've since been removed, apparently).  One was 48 hours out and one was 160ish out.  So, the AFD does apply to his first map that was showing snow/ice over TN.

 

Yep. And I was only replying to the guy from TN hint the AFD.

 

Nobody wants to see 48 hour potential, I won't post it. I don't live in TN anyway.  ^_^

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I just looked at the 00z euro and 6z gfs. I don't see a mechanism to lock in the cold. It seems transient from what I'm seeing.

It does not appear to be more than a ten day cold outbreak, but I could be wrong.  However, it does look like that each piece(though transient) will rotate down through eastern North America making it seem like the cold spell is locked in.  In reality, each cold air mass rotates through and the next one follows after a very brief period of moderation - which may be better to produce a good snowstorm.  Foothills mentioned this on his website yesterday, and I probably agree - he did not mention duration however.  So, there is some truth in saying it is not locked in IMO.  However, it may be cold enough that a warm spell is appreciated afterwards.  Now, what will be interesting is whether moisture can be transported north or get squashed.  In TN, we actually need a bit of a SE ridge to get storms.  Will the pattern of the past few months of moisture from the GOM being tapped interact w/ the pattern of cold coming around the 22nd?  I don't know and don't see evidence of this yet.  One met in TRI is now beating the cold drum. 

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It does not appear to be more than a ten day cold outbreak, but I could be wrong.  However, it does look like that each piece(though transient) will rotate down through eastern North America making it seem like the cold spell is locked in.  In reality, each cold air mass rotates through and the next one follows after a very brief period of moderation - which may be better to produce a good snowstorm.

 

This makes more sense logically...and perhaps better than a locked in dry cold suppressed storm track for "X" duration.

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Yep. And I was only replying to the guy from TN hint the AFD.

Nobody wants to see 48 hour potential, I won't post it. I don't live in TN anyway. ^_^

It's the only map you wont post. You have posted snow maps since nov and not one has verified. There is nothing to get excited about until we are within 72-96 hours. Several mets have discussed that for weeks. Yes looks to be heading in right direction but not there yet

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I too think that if we get to cold and it sticks, your just cold and dry.  I too like transient cold that allows a little warm up so it can bring the moisture with it.  I think very cold that doesn't loosen its grip will result in cold and dry.  Just my opinion.  I'm ready for fun and games to begin.  Right now its 62 degrees and I just put on shorts to go outside, this is crazy warm.

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IMO locked in cold is better than transient cold shots. January 2011 is a good example of that. Given the choice of a locked in cold pattern or transient I'd take locked in 10 times out of 10. Jmo.

 

Well I guess it depends on how cold we are talking about. I am not sure if Jan. 2011 featured snow storms going into a single digit air-mass or not. 

-

It looks like the NWS is talking about a sig. ice storm...so my meager ice potential comments may be conservative for those to our west. Not sure if it bleeds from Texas to TN or not. HPC does have a 80% chance of ice potential in west TN.

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So what do you get when the PNA is positive, AO is negative, and the NAO is neutral or slightly positive?

 

**over-running events or souther sliders?

 

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/teleconnections.shtml

 

Last week it was indicating the AO as negative, PNA as neutral, and the NAO as slightly negative.

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IMO locked in cold is better than transient cold shots. January 2011 is a good example of that. Given the choice of a locked in cold pattern or transient I'd take locked in 10 times out of 10. Jmo.

Marietta,

I don't even think a transient strong cold shot in late Jan. like what has been modeled is even close to a 100% probability. Although my confidence in at least a transient potent cold shot is increasing, it could still turn out to be a mirage.

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IMO locked in cold is better than transient cold shots. January 2011 is a good example of that. Given the choice of a locked in cold pattern or transient I'd take locked in 10 times out of 10. Jmo.

I agree with this, especially if the configuration of the ridge/trough complex over the US is aligned right.

On another note, at this point it seems premature to know whether or not a cold shot, which is more than a week away, will be transient or sustained. You could make a case for both, based on things like indicies, historical evidence, and teleconnections, but what should not be done is to base any conclusions on a 240+ hour model prog that might show in and out cold.

If you remember back to a couple of winters ago, the modeling kept showing long range warm-ups that never came. They often show cool downs that never come also. So it's probably a good idea to give them some time to figure out the pattern before declaring a cold snap or cold pattern.

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6z coming in a little snowier...

 

hour 48

GFS_3_2013011306_F48_SNOWIN_SURFACE.png

 

hour 120

GFS_3_2013011306_F120_SNOWIN_SURFACE.png

 

 

See, this is why people dont take you seriously. The sounding isnt even close for snow:

 

Date: 5 day AVN valid 6Z FRI 18 JAN 13Station: KAKHLatitude:   35.20Longitude: -81.15-------------------------------------------------------------------------------LEV PRES  HGHT  TEMP  DEWP  RH  DD   WETB DIR SPD THETA THE-V THE-W THE-E   W     mb     m     C     C    %   C     C  deg knt   K     K     K     K    g/kg-------------------------------------------------------------------------------SFC 1000   221   3.8   2.4  90  1.4   3.1  48   6 276.9 277.7 276.3 289.3  4.53  1 1000   222   4.8   2.0  82  2.8   3.6  49   8 278.0 278.7 276.7 290.1  4.43  2  950   640   3.5  -3.4  61  6.9   0.7  39  13 280.8 281.3 276.5 289.6  3.13  3  900  1076   0.5  -6.2  61  6.7  -2.0  13  11 282.0 282.5 276.5 289.6  2.67  4  850  1533  -0.8 -17.7  26 17.0  -5.5   2  13 285.3 285.5 276.0 288.7  1.12  5  800  2017  -1.0 -26.0  13 25.0  -6.9 359  14 290.1 290.2 277.6 292.0  0.57  6  750  2531  -1.4 -19.1  24 17.7  -6.5 323  11 295.1 295.3 280.7 298.6  1.12  7  700  3079  -2.6 -13.3  44 10.7  -6.2 279  15 299.6 300.0 283.7 305.8  1.96  8  650  3663  -5.7 -10.7  68  5.0  -7.5 270  22 302.5 303.0 285.5 310.6  2.60  9  600  4287  -8.7 -12.3  75  3.6  -9.9 263  26 306.1 306.5 286.7 313.9  2.47 10  550  4958 -12.3 -17.7  64  5.4 -13.9 255  33 309.5 309.8 287.1 315.1  1.72 11  500  5678 -17.7 -22.6  65  4.9 -18.8 253  36 311.5 311.7 287.3 315.7  1.25 12  450  6459 -22.0 -32.9  37 10.9 -23.9 268  37 315.5 315.6 287.9 317.4  0.53 13  400  7321 -23.9 -52.5   5 28.6 -26.6 270  49 323.9 323.9 290.0 324.2  0.07 14  350  8283 -31.0 -55.8   7 24.8 -32.7 256  66 327.0 327.0 290.9 327.2  0.06 15  300  9353 -40.7 -62.1   8 21.4 -41.5 249  73 327.9 328.0 291.2 328.1  0.03 16  250 10567 -50.3 -67.6  11 17.3 -50.7 250  80 331.3 331.3 292.1 331.3  0.02 17  200 11991 -59.0 -65.8  41  6.8 -59.1 249  90 339.3 339.3 294.1 339.4  0.03 18  150 13770 -64.5 -69.9  47  5.4 -64.5 249  97 359.1 359.1 298.5 359.1  0.02 19  100 16231 -65.9 -77.6  18 11.7 -66.0 250  82 400.4 400.4 305.3 400.4  0.01TRP                                             0                              WND                                             0                              
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