Jump to content
  • Member Statistics

    17,606
    Total Members
    7,904
    Most Online
    ArlyDude
    Newest Member
    ArlyDude
    Joined

January 17th-18th Winter Storm Discussion


BullCityWx

Recommended Posts

  • Replies 1.8k
  • Created
  • Last Reply

RAH says FAIL:

 

..INCREASING CONFIDENCE OF A SIGNIFICANT PRECIPITATION EVENT ACROSSTHE CAROLINAS...PRIMARILY A COLD WET ONE FOR CENTRAL NC...THU-THUNIGHT...THE SOUTHERN PORTION OF THE POSITIVELY-TILTED L/W TROUGH TO OUR WESTWILL UNDERGO DEAMPLIFICATION AS IT SHEARS EASTWARD IN BROAD CYCLONICAND INCREASINGLY PROGRESSIVE FLOW AT THE BASE OF A POWERFUL VORTEXSETTLING TOWARD HUDSON BAY. THIS S/W TROUGH WILL INTERACT WITH THEREMNANT ANOMALOUS TROPICAL MOISTURE PLUME -- ONE CHARACTERIZED BYPRECIPITABLE WATER VALUES BETWEEN 150-200% OF NORMAL OVER MUCH OFTHE SOUTHEAST -- AND CONSEQUENTLY PRODUCE AN AXIS OF SIGNIFICANTDEFORMATION PRECIPITATION ON THE NORTHWEST SIDE OF AN ACCOMPANYINGINCIPIENT SURFACE WAVE FORECAST TO MOVE QUICKLY OUT TO SEA (FROM THESAVANNAH BASIN). THE RECENT TREND IN THE NWP GUIDANCE HAS BEENTOWARD A FASTER...MORE AMPLIFIED...SLIGHTLY MORE NORTHERN...AND MUCHWETTER SOLUTION...THOUGH NOT TO THE DEGREE OF THE 12Z15TH NAM/WRF...WHICH IS CONSIDERED AN OUTLIER.ISENTROPIC UPGLIDE AND CONVERGENCE INTO THE H85 FRONTALZONE...WHICH HAD BECOME QUASI-STATIONARY ALONG THE CENTRALAPPALACHIANS PER 12Z/15TH RAOB DATA...BUT WILL SOON GET A NUDGEEASTWARD BY THE PROGRESSIVE NORTHERN PORTION OF THE L/W TROUGH TOOUR WEST...WILL RESULT IN THE RAPID RE-EXPANSION OF PRECIPITATIONINTO THE SOUTHERN AND WESTERN NC PIEDMONT EARLY IN THE DAY...AFTERJUST SOME LINGERING LIGHT SHOWERY CHARACATER/FRONTAL PRECIPITATIONWEDNESDAY NIGHT. THIS DEFORMATION SHIELD WILL THEN PIVOT EASTNORTHEASTWARD ACROSS THE REMAINDER OF CENTRAL NC DURING THEAFTERNOON AND EVENING HOURS...BEFORE ENDING FROM WEST TO EASTBETWEEN 03-10Z THU NIGHT.THE FASTER TIMING OF THE SYSTEM FAVORS EVEN MORE STRONGLY JUST ACHILLY RAIN FOR CENTRAL NC...THOUGH PARTIAL THICKNESSES DO CRASHTOWARD THE WINTRY MIXTURE PORTION OF THE NOMOGRAM AS THEPRECIPITATION IS COMING TO AN END. AS SUCH...THERE REMAINS A SMALLPROBABILITY THAT A FEW WET FLAKES MAY MIX WITH THE RAIN OVER THEWESTERN AND NORTHERN PIEDMONT. NO ACCUMULATION IS EXPECTED...GIVENBOTH THE BREVITY OF ANY SUCH OCCURRENCE...AS WELL AS PRECEDING WARMGROUND AND ABOVE FREEZING SURFACE TEMPERATURES - A NON-EVENT.
Link to comment
Share on other sites

Could a met answer this? Is this run much colder because that northern energy interacts with our low and forces it to go more negative? 

 

I am not sure that its so much the northern energy...I think *for the most part* its just because its strong PVA & its closed and bundled more.  I think the NAM is a bit too far north though.  

Link to comment
Share on other sites

RAH says FAIL:

 

..INCREASING CONFIDENCE OF A SIGNIFICANT PRECIPITATION EVENT ACROSSTHE CAROLINAS...PRIMARILY A COLD WET ONE FOR CENTRAL NC...THU-THUNIGHT...THE SOUTHERN PORTION OF THE POSITIVELY-TILTED L/W TROUGH TO OUR WESTWILL UNDERGO DEAMPLIFICATION AS IT SHEARS EASTWARD IN BROAD CYCLONICAND INCREASINGLY PROGRESSIVE FLOW AT THE BASE OF A POWERFUL VORTEXSETTLING TOWARD HUDSON BAY. THIS S/W TROUGH WILL INTERACT WITH THEREMNANT ANOMALOUS TROPICAL MOISTURE PLUME -- ONE CHARACTERIZED BYPRECIPITABLE WATER VALUES BETWEEN 150-200% OF NORMAL OVER MUCH OFTHE SOUTHEAST -- AND CONSEQUENTLY PRODUCE AN AXIS OF SIGNIFICANTDEFORMATION PRECIPITATION ON THE NORTHWEST SIDE OF AN ACCOMPANYINGINCIPIENT SURFACE WAVE FORECAST TO MOVE QUICKLY OUT TO SEA (FROM THESAVANNAH BASIN). THE RECENT TREND IN THE NWP GUIDANCE HAS BEENTOWARD A FASTER...MORE AMPLIFIED...SLIGHTLY MORE NORTHERN...AND MUCHWETTER SOLUTION...THOUGH NOT TO THE DEGREE OF THE 12Z15TH NAM/WRF...WHICH IS CONSIDERED AN OUTLIER.ISENTROPIC UPGLIDE AND CONVERGENCE INTO THE H85 FRONTALZONE...WHICH HAD BECOME QUASI-STATIONARY ALONG THE CENTRALAPPALACHIANS PER 12Z/15TH RAOB DATA...BUT WILL SOON GET A NUDGEEASTWARD BY THE PROGRESSIVE NORTHERN PORTION OF THE L/W TROUGH TOOUR WEST...WILL RESULT IN THE RAPID RE-EXPANSION OF PRECIPITATIONINTO THE SOUTHERN AND WESTERN NC PIEDMONT EARLY IN THE DAY...AFTERJUST SOME LINGERING LIGHT SHOWERY CHARACATER/FRONTAL PRECIPITATIONWEDNESDAY NIGHT. THIS DEFORMATION SHIELD WILL THEN PIVOT EASTNORTHEASTWARD ACROSS THE REMAINDER OF CENTRAL NC DURING THEAFTERNOON AND EVENING HOURS...BEFORE ENDING FROM WEST TO EASTBETWEEN 03-10Z THU NIGHT.THE FASTER TIMING OF THE SYSTEM FAVORS EVEN MORE STRONGLY JUST ACHILLY RAIN FOR CENTRAL NC...THOUGH PARTIAL THICKNESSES DO CRASHTOWARD THE WINTRY MIXTURE PORTION OF THE NOMOGRAM AS THEPRECIPITATION IS COMING TO AN END. AS SUCH...THERE REMAINS A SMALLPROBABILITY THAT A FEW WET FLAKES MAY MIX WITH THE RAIN OVER THEWESTERN AND NORTHERN PIEDMONT. NO ACCUMULATION IS EXPECTED...GIVENBOTH THE BREVITY OF ANY SUCH OCCURRENCE...AS WELL AS PRECEDING WARMGROUND AND ABOVE FREEZING SURFACE TEMPERATURES - A NON-EVENT.

 

 

Did you honestly expect any thing else??  As the modeling stood when they wrote the discussion, then yes, they are close, but as you know, they are ALWAYS conservative. A majority of their forecast area will be all rain.

They realize others read those discussions. 

Link to comment
Share on other sites

Yeah, but just looking at the thickness levels at no time does it seem there would be all snow over the triad... maybe some mixing, but it looks like mainly rain.  

Obviously, these maps are to be taken with about a ton of salt; I was just stating what the map showed :) In any case, it's better looking than 12z.

Link to comment
Share on other sites

Well, you folks in western NC will have to give us the play by play when the snow comes. Looks like the rest of NC will have to still wait.

Just looking at 850 temps and precip, it looks good for RDU as well. BUT at this shorter range I do start putting more trust in RAH. From what they are stating and looking at the models, I would say we have a good chance of rain mixing and then briefly changing to snow. Maybe some slush on the top of cars. For a "real" storm we're going to have to wait.   

Link to comment
Share on other sites

since we have many who live in Western NC frequenting this board (Franklin, Don, Met and others)... I'm pulling for them and expect to see a tad more expansive precip field on radar on the northern side of this system compared to what is currently shown on the GFS and Euro

 

although, the heaviest precip will certainly be under the upper low and highest vertical velocities... so being too far north in Western NC might not be as good of a position in this case

 

Balsam Mountains to Cataloochee are my pick to click

Yep I am sure the mountain folk are paying close attention to this one. We could have flooding then 24 hours we have 2-4 inches of snow. Got to love it.

Link to comment
Share on other sites

Looking at those ptype maps, there is a definite trend colder between 12z and 18z. Hopefully this trend holds.

I wonder if we'll see the GFS trend colder for the 18z run and catch up with the nam...the 12z lost the cold between hour 54 and 60, which was strange as temp-wise it looked close to the NAM up until hour 60. It will be interesting to see what the 00z suite holds.

Link to comment
Share on other sites

Text output shows 2 to 4 inches depending on ratios.  Not that bad, I'd say.

If it changed and fell heavy enough, I could see an inch or so for Knoxville...........that would be the max.  jmo. I don't think the text output takes into account the warm surfaces and the rates needed to overcome that and begin to accumulate.........

Link to comment
Share on other sites

If it changed and fell heavy enough, I could see an inch or so for Knoxville...........that would be the max.  jmo. I don't think the text output takes into account the warm surfaces and the rates needed to overcome that and begin to accumulate.........

Oh yes, of course.  Whatever falls will melt fast.

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

  • Recently Browsing   0 members

    • No registered users viewing this page.

×
×
  • Create New...