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Jan 25/26 Storm Part IV


burgertime

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I'm just hoping this continues to slow down until after 6 or 7pm wed. I think that make a bit of difference on accumulations.

I don't know what you got in the Mar 09 storm, but mine began around 5:30 pm or so and it was starting to get dark, Within 2 hours I had 3" I think, and was in constant melt,but the temps pretty much leveled off around 30 degrees, and each hour from then on really piled on so rapidly, it had no choice but to accumulate.

The day after:

post-38-0-94615600-1295894932.jpg

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yeah it and the NAM are really seeing something going on between 54 and 60 hours with the deformation band in western NC. Not sure but I think its related to the strengthening of the 5H as it goes from n. GA to near CLT to RDU and that pivot around the mountains somehow congeals and focuses the 7h moisture and omega there.

I agree with you and Burger. This upper low means business on the Euro as it really strengthens as it comes out of Bama. Always a good sign to see a strong upper low that is strengthening as it approaches if you want snow. I would not want to be driving on I-77 in SW Virginia tomorrow late morning to afternoon.

Edit: meant to say Wed

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I don't know what you got in the Mar 09 storm, but mine began around 5:30 pm or so and it was starting to get dark, Within 2 hours I had 3" I think, and was in constant melt,but the temps pretty much leveled off around 30 degrees, and each hour from then on really piled on so rapidly, it had no choice but to accumulate.

The day after:

]

Absolutely gorgeous Foothills....unfortunately I got 3" of rain in 33 degree temps. I was hoping that this storm would give me more snow than rain, but looks like it's getting more ane more rainy for me.

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Boy looking at the 12z Euro that ULL means business once it gets going in the foothills. Would love it if it could track just a little south and east but I'm not holding out too much hope.

Taken verbatim me and you would be watching it snow about a county away according to the 12Z EURO. The GGEM gives us some hope as it has shifted south at 12Z and would imply the souther end of the deformation band reaching the CLT area. However it is now southern outlier which is kind of odd since if memory serves me correctly its been a little too far north with its storms so far this winter.

FYI...Here is a link to the GGEM I use sometimes. It takes a little longer to update but the maps are very nice and the loops have 6hr increments instead of the 12hr that are on the main Environment Canada site. Enjoy!

GEM-GLB

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I don't know what you got in the Mar 09 storm, but mine began around 5:30 pm or so and it was starting to get dark, Within 2 hours I had 3" I think, and was in constant melt,but the temps pretty much leveled off around 30 degrees, and each hour from then on really piled on so rapidly, it had no choice but to accumulate.

The day after:

post-38-0-94615600-1295894932.jpg

I think that's the storm that gave me sleet for 3 hours while you were getting heavy snow. It was an odd setup. I think i had 5-6 inches.

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Taken verbatim me and you would be watching it snow about a county away according to the 12Z EURO. The GGEM gives us some hope as it has shifted south at 12Z and would imply the souther end of the deformation band reaching the CLT area. However it is now southern outlier which is kind of odd since if memory serves me correctly its been a little too far north with its storms so far this winter.

FYI...Here is a link to the GGEM I use sometimes. It takes a little longer to update but the maps are very nice and the loops have 6hr increments instead of the 12hr that are on the main Environment Canada site. Enjoy!

GEM-GLB

Thanks! We all know it's going to be painful for someone, all we need is just a small shift south so who knows? Not holding my breath though.

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Absolutely gorgeous Foothills....unfortunately I got 3" of rain in 33 degree temps. I was hoping that this storm would give me more snow than rain, but looks like it's getting more ane more rainy for me.

Thank you. Maybe this one could slide south, no guarantees but no certainties either with Upper lows. They're fun to watch happen. I'm expecting a good rain event finally here if nothing else.

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Thank you. Maybe this one could slide south, no guarantees but no certainties either with Upper lows. They're fun to watch happen. I'm expecting a good rain event finally here if nothing else.

Maybe it could...would be fun to watch unfold! Just how unpredictable are ULL's? Just wondering why this one is so hard to call an exact track on, even this close to the event. Aren't the tracks usually a little more predictable when it's 24 hours out? Or is it because it IS a ULL? Okay, enough questions...back to lurking, reading, and learning!

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Maybe it could...would be fun to watch unfold! Just how unpredictable are ULL's? Just wondering why this one is so hard to call an exact track on, even this close to the event. Aren't the tracks usually a little more predictable when it's 24 hours out? Or is it because it IS a ULL? Okay, enough questions...back to lurking, reading, and learning!

Virtually unpredictable until they form. Definately nowcast events *most* of the time. There are a few exceptions I'm sure. Upper level low=Weatherman's woe.

*back to lurking*

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After seeing the euro in the detail frames now, little doubt the area from wilkesboro to mt airy over to martinsville would get walloped. Probably 10-12 inches. The slp starts to deepen quickly once it hits the atlantic coastline and the deformation zone sets up from about avl up to the virginia border. The vorticiy aloft at hour 60 for the 5h vort is off the charts, literally. There is going to be an INTENSE band of snow on the northwest side of this. The SLP drops from around 1004 over southeast georgia at hour 48 to around 990MB at hour 60 over the norfolk area. Close to a 15mb drop in 12 hours.

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Maybe it could...would be fun to watch unfold! Just how unpredictable are ULL's? Just wondering why this one is so hard to call an exact track on, even this close to the event. Aren't the tracks usually a little more predictable when it's 24 hours out? Or is it because it IS a ULL? Okay, enough questions...back to lurking, reading, and learning!

ULL's are unpredictable because

A) we aren't sure where the path of the ULL will travel

B) If it's not raining hard, then the cold temperatures aloft might not make it to the surface or 850s, and it's what we are looking at in regards of potential snowfall. (Chances are, it will likely snow)

C) Like everyone said, the ULL will likely form a deformation band, which can be narrow. Pinpointing exactly where that band will form is tricky.

This storm has a winter and a spring like side to it, so it's not an easy forecast at all. Someone will be very happy, and others will be very upset.

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GSP not really buying into much snow east of the Apps with this one...yet...

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...

AS OF 245 AM MONDAY...THE TREND TOWARD A WARMER BOUNDARY LAYER

CONTINUES WITH THE LATEST MODEL GUIDANCE...WHILE THE MODELS CONTINUE

TO HAVE TIMING PROBLEMS AND RUN-TO-RUN INCONSISTENCY AS TO WHEN THE

MAIN SURFACE LOW WILL MOVE PAST. THE NEW FORECAST ATTEMPTS TO STRIKE

A COMPROMISE BETWEEN THE FASTER GFS/ECMWF AND THE SLOWER NAM AT

ONSET...AND THE SLOWER DEPARTURE OF THE ECMWF ON WEDNESDAY. THE

FORCING STILL LOOKS TREMENDOUS MOVING UP FROM THE SOUTH LATE TUESDAY

AND SPREADING ACROSS THE FORECAST AREA TUESDAY NIGHT...SO A

CATEGORICAL POP IS KEPT FOR THAT PERIOD. THE CATEGORICAL IS THEN

RETAINED FOR ALMOST THE ENTIRE FORECAST AREA WEDNESDAY MORNING OWING

TO THE SLOWER TIMING. PRECIP TYPE CONTINUES TO BE THE MAIN

PROBLEM...BUT MAINLY OVER THE HIGHER ELEVATIONS. EAST OF THE BLUE

RIDGE...THERE WILL BE THE POSSIBILITY OF A BRIEF PERIOD OF WET SNOW

AT ONSET ON TUESDAY AS THE BOUNDARY LAYER COOLS EVAPORATIVELY...BUT

WARM ADVECTION SHOULD QUICKLY OVERWHELM THIS AND CHANGE THE PRECIP

OVER TO A COLD RAIN FOR THE DURATION OF THE EVENT. MEANWHILE...

ACROSS THE MTNS...RAIN V. SNOW WILL BE MAINLY ELEVATION DEPENDENT ON

TUESDAY AS THE BOUNDARY LAYER OVER THE VALLEYS SHOULD BE

SUFFICIENTLY WARM ENOUGH TO MELT MOST OF THE SNOW. HOWEVER...WITH

SUNSET THIS WILL CHANGE AS THE BOUNDARY LAYER COOLS AND PRECIP RATES

INCREASE WITH THE BETTER FORCING MOVING IN AFTER SUNSET. THE NAM

PROFILES LOOK MORE REALISTIC OVER THE MTNS WITH A DEEP ISOTHERMAL

TEMP PROFILE EXPECTED NEAR FREEZING AS DYNAMIC COOLING AND PRECIP

DRAG OFFSET THE WARM ADVECTION. SO...MOST OF THE HIGHER ELEVATIONS

ARE PERMITTED TO CHANGE OVER TO SNOW FOR MOST OF TUESDAY NIGHT AND

INTO WEDNESDAY MORNING. CONSIDERATION OF QPF AND SNOW LEVELS WOULD

SUGGEST A GOOD CHANCE OF REACHING WARNING CRITERIA TUESDAY NIGHT AT

ELEVATIONS ABOVE 3500 FEET. HOWEVER...THERE REMAINS TOO MUCH

UNCERTAINTY ABOUT THE CHANGEOVER TO SNOW...THE TRACK OF THE PRIMARY

LOW...AND THE AMOUNT OF PRECIP...SO A WATCH WILL NOT BE ISSUED YET

FOR WHAT WOULD BE THE FOURTH PERIOD.

AS THE LOW PULLS AWAY ON WEDNESDAY AFTERNOON...COLD AIR WILL SPILL

IN FROM THE NW AND MOISTURE WILL GET FORCED UP THE W SIDE OF THE

MTNS. SO...PRECIP CHANCES BECOME CONFINED TO THE TN BORDER BY LATE

IN THE DAY. A BRIEF NW FLOW SNOW EVENT SHOULD CONTINUE THROUGH THE

EVENING AND PERHAPS WILL TAPER OFF TOWARD SUNRISE THURSDAY.

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GSP not really buying into much snow east of the Apps with this one...yet...

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...

AS OF 245 AM MONDAY...THE TREND TOWARD A WARMER BOUNDARY LAYER

CONTINUES WITH THE LATEST MODEL GUIDANCE...WHILE THE MODELS CONTINUE

TO HAVE TIMING PROBLEMS AND RUN-TO-RUN INCONSISTENCY AS TO WHEN THE

MAIN SURFACE LOW WILL MOVE PAST. THE NEW FORECAST ATTEMPTS TO STRIKE

A COMPROMISE BETWEEN THE FASTER GFS/ECMWF AND THE SLOWER NAM AT

ONSET...AND THE SLOWER DEPARTURE OF THE ECMWF ON WEDNESDAY. THE

FORCING STILL LOOKS TREMENDOUS MOVING UP FROM THE SOUTH LATE TUESDAY

AND SPREADING ACROSS THE FORECAST AREA TUESDAY NIGHT...SO A

CATEGORICAL POP IS KEPT FOR THAT PERIOD. THE CATEGORICAL IS THEN

RETAINED FOR ALMOST THE ENTIRE FORECAST AREA WEDNESDAY MORNING OWING

TO THE SLOWER TIMING. PRECIP TYPE CONTINUES TO BE THE MAIN

PROBLEM...BUT MAINLY OVER THE HIGHER ELEVATIONS. EAST OF THE BLUE

RIDGE...THERE WILL BE THE POSSIBILITY OF A BRIEF PERIOD OF WET SNOW

AT ONSET ON TUESDAY AS THE BOUNDARY LAYER COOLS EVAPORATIVELY...BUT

WARM ADVECTION SHOULD QUICKLY OVERWHELM THIS AND CHANGE THE PRECIP

OVER TO A COLD RAIN FOR THE DURATION OF THE EVENT. MEANWHILE...

ACROSS THE MTNS...RAIN V. SNOW WILL BE MAINLY ELEVATION DEPENDENT ON

TUESDAY AS THE BOUNDARY LAYER OVER THE VALLEYS SHOULD BE

SUFFICIENTLY WARM ENOUGH TO MELT MOST OF THE SNOW. HOWEVER...WITH

SUNSET THIS WILL CHANGE AS THE BOUNDARY LAYER COOLS AND PRECIP RATES

INCREASE WITH THE BETTER FORCING MOVING IN AFTER SUNSET. THE NAM

PROFILES LOOK MORE REALISTIC OVER THE MTNS WITH A DEEP ISOTHERMAL

TEMP PROFILE EXPECTED NEAR FREEZING AS DYNAMIC COOLING AND PRECIP

DRAG OFFSET THE WARM ADVECTION. SO...MOST OF THE HIGHER ELEVATIONS

ARE PERMITTED TO CHANGE OVER TO SNOW FOR MOST OF TUESDAY NIGHT AND

INTO WEDNESDAY MORNING. CONSIDERATION OF QPF AND SNOW LEVELS WOULD

SUGGEST A GOOD CHANCE OF REACHING WARNING CRITERIA TUESDAY NIGHT AT

ELEVATIONS ABOVE 3500 FEET. HOWEVER...THERE REMAINS TOO MUCH

UNCERTAINTY ABOUT THE CHANGEOVER TO SNOW...THE TRACK OF THE PRIMARY

LOW...AND THE AMOUNT OF PRECIP...SO A WATCH WILL NOT BE ISSUED YET

FOR WHAT WOULD BE THE FOURTH PERIOD.

AS THE LOW PULLS AWAY ON WEDNESDAY AFTERNOON...COLD AIR WILL SPILL

IN FROM THE NW AND MOISTURE WILL GET FORCED UP THE W SIDE OF THE

MTNS. SO...PRECIP CHANCES BECOME CONFINED TO THE TN BORDER BY LATE

IN THE DAY. A BRIEF NW FLOW SNOW EVENT SHOULD CONTINUE THROUGH THE

EVENING AND PERHAPS WILL TAPER OFF TOWARD SUNRISE THURSDAY.

They really don't buy into much until they have consistency, and cold, hard evidence with the guidance. Cant blame them though..

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Maybe it could...would be fun to watch unfold! Just how unpredictable are ULL's? Just wondering why this one is so hard to call an exact track on, even this close to the event. Aren't the tracks usually a little more predictable when it's 24 hours out? Or is it because it IS a ULL? Okay, enough questions...back to lurking, reading, and learning!

Hey there DawgKitten! I hope all is well. ULL's can be VERY TOUGH to predict. A great example is the Jan 2003 storm for the NC region. NWS-GSP (one of the best NWS offices in the country) and the weather board did not see it coming and I ended up with close to 12" of snow in Belmont, NC (may have been 10", so dont quote me). However, the original call was for advisory level snow of 1-2"!!! Amazing storm!

Pro's, please correct me if I am wrong about that or if any wording has to be changed. Thanks!

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In the March 2009 storm, it started raining at 38 degrees at my home in eastern Burke County. About 15 minutes later, heavy snow started to fall and we ended up with 4 inches of snow with the temperature plummeting to 32. Earlier that day, it rained with the rain ending as snow at around midday. During this storm, there was also a lightning strike with thunder during the heavy snow. These upper level lows have a mind of their own. Some areas will be surprised by this upper level low. The NAM shows approximately .5 of an inch of heavy wet snow falling over my area. This could easily accumulate to 3 inches of snow. I would not be surprised if someone in the foothills of NC (Burke, Catawba, Caldwell, Cleveland, Rutherford, Lincoln) would pick up close to 3-6 inches or more of snow. These things are wild and crazy, and no one will know where this heavy band of snow will set up until Wednesday.

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GSP not really buying into much snow east of the Apps with this one...yet...

AS THE LOW PULLS AWAY ON WEDNESDAY AFTERNOON...COLD AIR WILL SPILL

IN FROM THE NW AND MOISTURE WILL GET FORCED UP THE W SIDE OF THE

MTNS. SO...PRECIP CHANCES BECOME CONFINED TO THE TN BORDER BY LATE

IN THE DAY. A BRIEF NW FLOW SNOW EVENT SHOULD CONTINUE THROUGH THE

EVENING AND PERHAPS WILL TAPER OFF TOWARD SUNRISE THURSDAY.

I can't believe they didn't mention the deformation band in WNC late Wednesday, only the upslope. I guess they aren't buying into one.

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Quick question: Could a ULL directly over you produce snowfall, even if surface temperatures are above freezing? Or, is it a rule that you must be on the NW side of the ULL?

if it was very wrapped up and stacked and mature, definitely. This one is progressive and doesn't have time to spin like true cut offs we see in Spring.

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I can't believe they didn't mention the deformation band in WNC late Wednesday, only the upslope. I guess they aren't buying into one.

I was thinking the same thing. Perhaps there is so much uncertainty they are just leaving it out of the discussion for right now. The way things are looking to come together someone could go from nothing to winter storm warnings in a hurry.

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I can't believe they didn't mention the deformation band in WNC late Wednesday, only the upslope. I guess they aren't buying into one.

Robert, That is the AM AFD. They just came out with the PM AFD and it is in there. I would link it but am at work. It is pretty much a re-hash of this thread throughout the day.

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Quick question: Could a ULL directly over you produce snowfall, even if surface temperatures are above freezing? Or, is it a rule that you must be on the NW side of the ULL?

Keep in mind that it can, will, and has often snowed with temperatures above freezing. The Christmas storm here featured above freezing temperatures during the day, yet will still picked up a couple inches of daytime accumulations.

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"THE REALLY INTERESTING STUFF OCCURS ON WEDNESDAY...AS THE UPPER LOW

TRACKS (SOMEWHERE) OVER THE CWFA. ALL THE OPERATIONAL AND NON-

OPERATIONAL MODELS PRODUCE A BAND OF HEAVY PRECIP WITHIN THE

DEFORMATION ZONE NORTH OF THE H5 LOW TRACK. IN FACT...THE NAM

PRODUCES IN EXCESS OF AN INCH OF QPF IN A 6-HOUR PERIOD. THERE

APPEARS TO BE A GENERAL MODEL CONSENSUS THAT THIS HEAVIER PRECIP

WILL OCCUR ACROSS THE MTNS DURING THE LATE MORNING/EARLY AFTERNOON.

WITH THE COLD CORE LOW PASSING OVER THE REGION...SNOW LEVELS WILL

PLUMMET...AND WE WOULD EXPECT ANY PRECIP TO FALL MAINLY AS SNOW

EXCEPT IN THE LOWEST VALLEYS (BELOW 2500 FEET)...WHERE RAIN OR A

RA/SN MIX WOULD BE THE PRIMARY P-TYPE. WE ARE GETTING CLOSE TO THE

WATCH PERIOD OF THE FORECAST. HOWEVER...DUE TO THE UNCERTAINTY OF

THE EVENTUAL TRACK OF THE UPPER LOW...AND UNCERTAINTY REGARDING

TIMING AND THERMAL STRUCTURE...I CANT JUSTIFY ISSUING A WATCH ATTM."

There it is..

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