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3/6 - 3/7 Event is it this seasons last gasp?


WXinCanton

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From NWS Raleigh.

AS OF 945 PM THURSDAY...

CHALLENGING FORECAST OVERNIGHT INTO FRIDAY MORNING WITH SEVERAL

POSSIBLE SCENARIOS PLAUSIBLE. MAIN ADJUSTMENT WAS TO ADD WARREN

COUNTY TO THE ADVISORY BASED ON REPORTS OF SLEET COVERING THE GROUND

AND EXPECTATIONS OF THE THE LOW LEVEL COLD AIR REMAINING IN PLACE A

LITTLE LONGER THAN EARLIER THINKING.

LATEST SFC MESOANALYSIS INDICATES SFC PATTERN IN A CLASSIC CAD

SIGNATURE WITH THE RIDGE NOSES INTO THE NC PIEDMONT FROM A PARENT

HIGH CENTERED OVER BOSTON AT 01Z. PER LOW LEVEL STREAMLINE ANALYSIS

THIS FEATURE STILL SUPPLYING TEH WESTERN PIEDMONT WITH COOL DRY AIR.

MEANWHILE SFC LOW WAS OFF THE NE FL COAST LIFTING NE. THE TIGHT

PRESSURE GRADIENT BETWEEN THESE TWO WEATHER SYSTEM WAS CREATING

BLUSTERY NE ACROSS THE FORECAST AREA WITH GUSTS AROUND 30MPH IN THE

SANDHILLS AND SOUTHERN COASTAL PLAIN.

PRECIPITATION HAS OVERSPREAD THE FORECAST AREA WITH RAIN FALLING

ACROSS THE SOUTHERN COUNTIES INTO THE CENTRAL AND SOUTHERN COASTAL

PLAIN. A SWITCH TO A WINTRY MIX OCCURS IMMEDIATELY NORTH AND WEST OF

THIS REGION WITH PREDOMINATELY FREEZING RAIN/SLEET OCCURRING IN THE

NW PIEDMONT-TRIAD AND INTO THE FAR NORTHERN PIEDMONT NEAR THE VA

BORDER.

GSO 00Z SOUNDING DEPICTS A MODEST WARM NOSE AROUND 1 DEG C THOUGH

DOES SUGGEST AT A DEEP ISOTHERMAL LAYER BETWEEN 850-765MB. THIS

DEPICTION CLOSEST TO THE 12Z GFS WHILE 12Z NAM APPEARED TOO WARM

WITH THE WARM NOSE. DID NOTE THAT MHX 00Z SOUNDING HAD A WARM NOSE

AROUND 7 DEG C. WITH A STRONG LOW LEVEL ELY FLOW AROUND THE

APPROACHING SFC LOW...THIS POCKET OF WARM AIR WILL LIKELY TRANSLATE

EAST INTO AT LEAST THE COASTAL PLAIN...SANDHILLS AND PORTIONS OF THE

EASTERN PIEDMONT...KEEPING PRECIP ALL RAIN.

QUESTION ONE: HOW FAR WEST WILL THIS WARMER AIR REACH? BASED ON LOW

LEVEL STREAMLINES...THE WARMER AIR IN THE COASTAL PLAIN WILL MAKE IT

AS FAR WEST AS HIGHWAY ONE...AND POSSIBLY INTO THE WESTERN PIEDMONT.

THUS COULD SEE WARM NOSE ALOFT STRENGTHEN A BIT AFTER MIDNIGHT. 00Z

UPPER AIR ANALYSIS DID DEPICT DECENT MID-UPPER LEVEL CONFLUENCE IN

VICINITY OF THE PARENT HIGH WHICH SUGGEST THE HIGH SHOULD REMAIN

ANCHORED A BIT LONGER THAN ADVERTISED BY THE GFS (WHICH PUSHED THE

PARENT HIGH WILL OFFSHORE BY FRIDAY MORNING). THUS...CAD CONDITIONS

SHOULD PERSIST THROUGH THE OVERNIGHT INTO EARLY FRIDAY.

THUS FOR THE NEXT FEW HOURS...EXPECT A MIXTURE OF WINTRY PRECIP OVER

THE FAR NORTHERN PIEDMONT AND THE NW PIEDMONT WITH PRECIP RATES

DICTATING DOMINATE P-TYPE(HEAVIER RATES FAVOR SNOW AND SLEET,

LIGHTER AMOUNTS FREEZING RAIN).

AFTER 06Z...APPEARS THAT WESTERN PIEDMONT WILL COME UNDER THE

INFLUENCE OF MID LEVEL DEFORMATION ZONE AS MID LEVEL CYCLONE TAKES

SHAPE OVER CENTRAL SC. THIS SHOULD ENHANCE PRECIP RATES ACROSS THE

WESTERN PIEDMONT LATE TONIGHT INTO EARLY FRIDAY. DURING THIS

TIME...PARTIAL THICKNESSES REMAIN IN THE WINTRY MIX PORTION OF THE

NOMOGRAM WHILE THE RAP BUFKIT SOUNDINGS DEPICT A FAIRLY DEEP

ISOTHERMAL LAYER (FAVOR SNOW) WITH THE GFS AND NAM MAINTAINING A

PROMINENT WARM NOSE (ESPECIALLY THE NAM AT 4 DEG C). WITH THE NEAR

SURFACE AIR MASS STILL DICTATED BY THE CHILLY PARENT HIGH AND AN

INCREASE IN PRECIP RATES AFTER MIDNIGHT...EXPECT A COMBINATION OF

SNOW AND FREEZING RAIN OVER THE WARNING AND ADVISORY AREA. SINCE

PRECIP WILL BE MIXED...THIS WILL CUT BACK ON ANY ONE P-TYPE

ACCUMULATING TO OUTRAGEOUS AMOUNTS. IF SNOW WERE TO

PREDOMINATE...COULD SEE AMOUNTS IN EXCESS OF 6 INCHES OCCUR.

CONVERSELY...IF IT WERE ALL FREEZING RAIN...ICE ACCRUAL A QUARTER TO

A HALF INCH PROBABLE. SINCE A MIX EXPECTED...EXPECT SNOW AMOUNTS TO

RANGE FROM A TRACE ALONG THE EASTERN FRINGE OF THE ADVISORY TO 2-3

INCHES WITH POCKETS OF 4 INCHES IN THE WARNING AREA. ICE ACCRUAL

APPROACHING A QUARTER OF AN INCH IN THE WARNING AREA...TRENDING TO A

TENTH OF AN INCH OR LESS IN THE ADVISORY. EVEN ON THE FRINGES

OUTSIDE OF ADVISORY (NORTHERN MOORE...LEE...WESTERN AND NORTHERN

WAKE AND WESTERN FRANKLIN)...A POCKET OR TWO OF LIGHT GLAZE POSSIBLE

BUT LIMITED EFFECTS SUGGEST KEEPING THIS AREA OUT FO TEH ADVISORY

FOR NOW.

WILL NEED TO MONITOR DEVELOPMENT OF DEFORMATION OVERNIGHT INTO

FRIDAY MORNING ALONG WITH MODEL/OBSERVED SOUNDING THERMAL

PROFILES...POTENTIAL FOR A QUICK BURST OF WET SNOW FRIDAY MORNING

OVER SECTIONS OF THE PIEDMONT...MAINLY WESTERN SECTIONS....AS MID-

UPPER LEVEL CYCLONE LIFTS NE OVER COASTAL CAROLINA.

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From NWS Raleigh.

AS OF 945 PM THURSDAY...

CHALLENGING FORECAST OVERNIGHT INTO FRIDAY MORNING WITH SEVERAL

POSSIBLE SCENARIOS PLAUSIBLE. MAIN ADJUSTMENT WAS TO ADD WARREN

COUNTY TO THE ADVISORY BASED ON REPORTS OF SLEET COVERING THE GROUND

LATEST SFC MESOANALYSIS INDICATES SFC PATTERN IN A CLASSIC CAD

.EXPECT A MIXTURE OF WINTRY PRECIP OVER

THE FAR NORTHERN PIEDMONT AND THE NW PIEDMONT WITH PRECIP RATES

DICTATING DOMINATE P-TYPE(HEAVIER RATES FAVOR SNOW AND SLEET,

LIGHTER AMOUNTS FREEZING RAIN).

.EXPECT SNOW AMOUNTS TO

RANGE FROM A TRACE ALONG THE EASTERN FRINGE OF THE ADVISORY TO 2-3

INCHES WITH POCKETS OF 4 INCHES IN THE WARNING AREA. ICE ACCRUAL

APPROACHING A QUARTER OF AN INCH IN THE WARNING AREA...TRENDING TO A

.

Definitely heavier sleet and snow in bands back to zr when rates slow.

post-8756-0-53334800-1394162134_thumb.jp

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Since people are hugging the nam qpf output, here is something I was just looking at on the 00z run of the 4KM...ptype should change over from snow to just IP or ZR mix.  Some snow still for WNC highcountry.  I just don't see the snow threat as some are.

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Since people are hugging the nam qpf output, here is something I was just looking at on the 00z run of the 4KM...ptype should change over from snow to just IP or ZR mix. Some snow still for WNC highcountry. I just don't see the snow threat as some are.

Agreed. Snow threat has rapidly come to an end here in Asheville with temps in the mid to upper 30s. All rain this evening.

Sent from my iPhone using Tapatalk

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Did Buncombe not even have a delay this morning? Looks like I'm back to just normal rain here

man all we had was some snow last night about 6 it was snowing heavily and then it changed to rain and snow and that is all we had all night other than a little snow this morning which didn't amount to anything.  thought Buncombe would have at the very least 2 or 3 inches and maybe even 6.  what a no show.  this would have made me happy until next winter.  I know we've had snow later than this even in April but climo says we are running out of time if we haven't already.   :axe::cry:

 

 

Edit.  Kudos to all you guys who stuck with that we weren't going to get much snow out of this system.  great job to you guys.  I just thought once the snow started last night the temp would fall to the upper 20's.  but never happend it rose from 34 to 36.

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12z TRAP keeps the deform band over the western and central piedmont going strong through about hour 7, before shifting it east and weakening some. It lines up well with the Hardly Reliable Rarely Right, which shows virtually the same thing.

I have to admit I was wrong about the wintry impacts of this storm around the Triad area. I felt like the high would migrate out a little quicker, shutting off the cold air feed. The damming wasn't really enough for areas much outside the Triad, like I thought, but it was plenty for you guys up there.

The rain has been very robust, and looks to continue for a while. I guess the NAM, in this case, actually did ok with the QPF. The GFS was awful, until the last minute. I'm not sure how to ever really know which model, if any, will be right about the QPF. It seems to change every storm.

Anyway, congrats to all seeing wintry weather. I hope those without power get it restored quickly.

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Very dynamic storm with very impressive QPF.   Was interesting to observe the differing temperature profiles, the special soundings that were sent up last night along with the Dual Pole Correlation Radar Scans.   Even in the mountains there were those that did not get their fair share as the eastern side of the escarpment was in a more favorable setup.   Overall, this storm, even though it did not produce for all, had the characteristics and feel of a long running solid North Carolina winter storm.   

 

What a storm this could have been for all of us had this had come in with some blocking in place to lock in the cold air.

 

For those of us that enjoy winter, we hate to see it slip away.   We have way to much heat to deal with during the summer that makes winter weather a pleasure.    Hopefully at least one more good snow in the High Country before the season is done.

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3/6-7 SE winter storm post mortem: 

 

 Being that this storm had the most impressive setup BY FAR of a strong high/wedge and a Gulf low for 3/1-15 of any between 1969 and 2003 (I didn't have a chance to see 2004-2013), I'm not at all surprised about the severe ZR/IP effects on parts of NC, including the Triad and just west of the Triangle. Also, with such strong CAD, I'm not at all surprised about major IP and ZR being a big part of this despite it being March. As I've been saying, this was far from a typical March setup and, therefore, the idea that IP/ZR is a rarity in March was irrelevant in this case. Actually, it isn't as rare as many seem to think per my research of events from the 1940's to 1990's.

 

 With that great setup and although I didn't predict it, I had been thinking that N GA/upstate at least had a good shot at much more than the little that they received, especially when I saw that TD's were verifying 5-10 lower than even the 0Z 3/6 NAM/GFS last minute consensus. The only thing I had been concerned about was that the Gulf low was too far east for the best setup to give N GA more precip. and also to ttotally take advantage of the wedge. The high was in a fantastic position per climo/history. That's why I kept saying that I hoped the Gulf low was further west initially. Climo says that once a low gets east of your longitude in N GA, the moisture sometimes starts lessening. Once it is off of the SE coast..say near Savannah, the heaviest precip. is usually all done because the low sort of takes the precip with it. Surface lows already off of the SE coast usually do little for most of N GA although lagging upper energy will sometimes do its part then. Notice that yesterday's surface low related rain missed NW GA for the most part. It was the lagging upper low that gave NW Ga most of its precip.

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3/6-7 SE winter storm post mortem: 

 

 Being that this storm had the most impressive setup BY FAR of a strong high/wedge and a Gulf low for 3/1-15 of any between 1969 and 2003 (I didn't have a chance to see 2004-2013), I'm not at all surprised about the severe ZR/IP effects on parts of NC, including the Triad and just west of the Triangle. Also, with such strong CAD, I'm not at all surprised about major IP and ZR being a big part of this despite it being March. As I've been saying, this was far from a typical March setup and, therefore, the idea that IP/ZR is a rarity in March was irrelevant in this case. Actually, it isn't as rare as many seem to think per my research of events from the 1940's to 1990's.

 

 With that great setup and although I didn't predict it, I had been thinking that N GA/upstate at least had a good shot at much more than the little that they received, especially when I saw that TD's were verifying 5-10 lower than even the 0Z 3/6 NAM/GFS last minute consensus. The only thing I had been concerned about was that the Gulf low was too far east for the best setup to give N GA more precip. and also to ttotally take advantage of the wedge. The high was in a fantastic position per climo/history. That's why I kept saying that I hoped the Gulf low was further west initially. Climo says that once a low gets east of your longitude in N GA, the moisture sometimes starts lessening. Once it is off of the SE coast..say near Savannah, the heaviest precip. is usually all done because the low sort of takes the precip with it. Surface lows already off of the SE coast usually do little for most of N GA although lagging upper energy will sometimes do its part then. Notice that yesterday's surface low related rain missed NW GA for the most part. It was the lagging upper low that gave NW Ga most of its precip.

yep I like it when the moisture field comes out of the gulf northeast.  yesterday's moisture was coming more from the south so we got less moisture in the asheville area.  as it was also moving east, out of the gulf and northeast movement into cold air is when we get hit real good.  when I saw the moisture moving east northeast yesterday I thought we were in trouble.  as  you said storm a little to far south and east for N GA and WNC and Upstate. 

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yep I like it when the moisture field comes out of the gulf northeast. yesterday's moisture was coming more from the south so we got less moisture in the asheville area. as it was also moving east, out of the gulf and northeast movement into cold air is when we get hit real good. when I saw the moisture moving east northeast yesterday I thought we were in trouble. as you said storm a little to far south and east for N GA and WNC and Upstate.

I got plenty of moisture -3.01 total. The cold air was lacking! This was about 3 degrees too war for something memorable!
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3/6-7 SE winter storm post mortem: 

 

 Being that this storm had the most impressive setup BY FAR of a strong high/wedge and a Gulf low for 3/1-15 of any between 1969 and 2003 (I didn't have a chance to see 2004-2013), I'm not at all surprised about the severe ZR/IP effects on parts of NC, including the Triad and just west of the Triangle. Also, with such strong CAD, I'm not at all surprised about major IP and ZR being a big part of this despite it being March. As I've been saying, this was far from a typical March setup and, therefore, the idea that IP/ZR is a rarity in March was irrelevant in this case. Actually, it isn't as rare as many seem to think per my research of events from the 1940's to 1990's.

 

 With that great setup and although I didn't predict it, I had been thinking that N GA/upstate at least had a good shot at much more than the little that they received, especially when I saw that TD's were verifying 5-10 lower than even the 0Z 3/6 NAM/GFS last minute consensus. The only thing I had been concerned about was that the Gulf low was too far east for the best setup to give N GA more precip. and also to ttotally take advantage of the wedge. The high was in a fantastic position per climo/history. That's why I kept saying that I hoped the Gulf low was further west initially. Climo says that once a low gets east of your longitude in N GA, the moisture sometimes starts lessening. Once it is off of the SE coast..say near Savannah, the heaviest precip. is usually all done because the low sort of takes the precip with it. Surface lows already off of the SE coast usually do little for most of N GA although lagging upper energy will sometimes do its part then. Notice that yesterday's surface low related rain missed NW GA for the most part. It was the lagging upper low that gave NW Ga most of its precip.

i think the fact that the surface low and ULL were not vertically stacked and were so far apart killed it for us. The surface low took much of the energy east with it.

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By all accounts, this was a Miller A. Miller As are typically associated with Snow and Rain. In this case, there was wedging, which accounted for cold surface temps, even though the air aloft didn't seem to cool or cold air didn't get drawn into the storm.

My question is, why, in this case, did colder air not get drawn into the storm. It seemed to have a fairly stout warm nose. Is it just that the high, while in a good position to deliver CAD, was not in a good position to deliver cold into the mid levels of the cyclone? Why was the warm nose so prominant here?

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By all accounts, this was a Miller A. Miller As are typically associated with Snow and Rain. In this case, there was wedging, which accounted for cold surface temps, even though the air aloft didn't seem to cool or cold air didn't get drawn into the storm.

My question is, why, in this case, did colder air not get drawn into the storm. It seemed to have a fairly stout warm nose. Is it just that the high, while in a good position to deliver CAD, was not in a good position to deliver cold into the mid levels of the cyclone? Why was the warm nose so prominant here?

 

I think that more than anything, this just shows that every SE storm setup is different due to the complexities of the atmosphere, which is fascinating and humbling to me.

 

 There was snow but further north and west than you. But it was far more than just snow and rain due to the great CAD. Remember that research you aksed me to do of other Miller A's that caused widespread GA/SC/NC ice/IP?

If a Miller A also has CAD, it can have a wide band of IP/ZR.

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I think that more than anything, this just shows that every SE storm setup is different due to the complexities of the atmosphere, which is fascinating to me.

 

 There was snow but further north than you. But it was far more than just snow and rain due to the CAD. remember that research you aksed me to do of other miller A's that caused widespread GA/SC/NC ice/IP?

 

Yes sir! Remember that well! Just thinking through this, the setup seemed to be very atypical, as indicated by what you pointed out about this being the first situation you found like this for the first 15 days of March. I usually think of strong CADs associated with Miller Bs or Overrunning or something other than a well-developed Miller A. I am probably in error in thinking that way.

It's kind of surprising to me (maybe it shouldn't be, but it is) that if a high is strong enough to deliver enough cold such as to create a major icing event with a Miller A, then there ought to be enough cold air to also create an expansive show shield. In this case, there was snow, but there was much more wintry mix and of course, rain. With strong CADding and a Miller B, it wouldn't be surprising to see less snow and more wintry mix and more rain, because the thermal profiles are dirtier. A Miller A should have had better cold upstairs. That's what I feel like, anyway. That make sense? I'm probably wrong in the way I'm looking at it, but it seems like a good, strong high, if it can create good, strong CADding, should be able to make for a colder vertical thermal profile....unless the cold was super shallow and/or the high wasn't in the right position in relation to the storm to be able to do it.

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It's kind of surprising to me (maybe it shouldn't be, but it is) that if a high is strong enough to deliver enough cold such as to create a major icing event with a Miller A, then there ought to be enough cold air to also create an expansive show shield. In this case, there was snow, but there was much more wintry mix and of course, rain. With strong CADding and a Miller B, it wouldn't be surprising to see less snow and more wintry mix and more rain, because the thermal profiles are dirtier. A Miller A should have had better cold upstairs. That's what I feel like, anyway. That make sense? I'm probably wrong in the way I'm looking at it, but it seems like a good, strong high, if it can create good, strong CADding, should be able to make for a colder vertical thermal profile....unless the cold was super shallow and/or the high wasn't in the right position in relation to the storm to be able to do it.

 

CR,

 What I bolded is my educated guess. The high's position as well as strength were fantastic imo although I feel that a low further west in the GOM may have worked with it more effectively. I'm still wondering about that. The cold did seem to be super shallow as would be consistent with a sharp turn to SW 500 mb flow ahead of the upper low. That SW flow made it very moist for NC but also made it warmer than it would otherwise be upstairs imo. For some storms it is closer to WSW flow, which probably means less shallow cold in CAD highs in many cases.

 

 Opinion?

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CR,

 What I bolded is my educated guess. The high's position as well as strength were fantastic imo although I feel that a low further west in the GOM may have worked with it more effectively. I'm still wondering about that. The cold did seem to be super shallow as would be consistent with a sharp turn to SW 500 mb flow ahead of the upper low. That SW flow made it very moist for NC but also made it warmer than it would otherwise be upstairs imo. For some storms it is closer to WSW flow, which probably means less shallow cold in CAD highs in many cases.

 

 Opinion?

 

Yeah, Larry, what you said is about as good of a reason as I can come up with. I have noticed that the best position for a high for a Miller A snowstorm is over the Lakes or slightly S or SW of there -- not New England. Maybe in that scenario it is somehow able to funnel cold into the storm more efficiently at the mid levels? Often in that setup, you'll see a seconary (banana-type) high in the NE somewhere, but having the main high of sufficient strength back west a little seems to correlate good with more snow-type events. I dunno.

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i think the biggest deal with what went "wrong" so to speak is this sucker got really wrapped up and produced a lot of latent heat. This storm has some insane QPF outputs and atlantic maritime air got involved in enhancing rates which just really didn't work out for most of us.

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i think the biggest deal with what went "wrong" so to speak is this sucker got really wrapped up and produced a lot of latent heat. This storm has some insane QPF outputs and atlantic maritime air got involved in enhancing rates which just really didn't work out for most of us.

Yeah, it's been a prolific precip producer. Here in Raleigh, it's been raining, virtually non-stop since around 4:00 pm or so yesterday. And it's still pouring. The death band that's been parked over the central/western piedmont areas is slowly working east. We've been on the eastern fringes of that. Man, if only the temps were just a few meager degrees cooler, what a snowstorm this would have been! 

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Yeah, it's been a prolific precip producer. Here in Raleigh, it's been raining, virtually non-stop since around 4:00 pm or so yesterday. And it's still pouring. The death band that's been parked over the central/western piedmont areas is slowly working east. We've been on the eastern fringes of that. Man, if only the temps were just a few meager degrees cooler, what a snowstorm this would have been! 

 

 

If I had a dollar for everytime I have ever said that...... :whistle:

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If I had a dollar for everytime I have ever said that...... :whistle:

 

Haha! I know what you mean.

Here's the Raleigh doppler rainfall estimate. Cool how it thinks there was over 12" of QPF in Caswell County. That zone just northeast of Fayetteville must be like the Waycross of NC or something.

post-987-0-64395700-1394218391_thumb.gif

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Haha! I know what you mean.

Here's the Raleigh doppler rainfall estimate. Cool how it thinks there was over 12" of QPF in Caswell County. That zone just northeast of Fayetteville must be like the Waycross of NC or something.

That's MBY :) well at least until spring then I'm moving closer near Raleigh
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