Sunday, March 1, 2015

Freezing Rain This Morning


Winter Wx Advisories have been hoisted for the overnight hours from 3AM - 5PM tomorrow for about a tenth of an inch of freezing rain and minor sleet accumulation.

Davie and Rowan counties under WWA's - either the same or Freezing Rain Advisories out for the majority of NC. Only difference being the NWS thinks it is possible some sleet/snow mixes in at the beginning in WWA counties and just freezing rain in others - talking very minimal before turns to freezing rain, which will also be minimal.

However, if enough precip falls it could make bridges/roads icy so be careful in the morning. Most likely just a tree branch / elevated surfaces ice glaze expected.

The NWS forecast for Rowan/Davie (GSP) has issued the following accumulation / forecast map, which lists Farmington as the top ice winner with expected .11" and Salisbury close but a mere hundredth off... Right...


So mainly nuisance type event with temps rising above freezing and therefore erasing any ice by the mid-afternoon if not sooner.

Current temps are below 32ยบ now most places or will be per wet bulb temps. 


Here is the WPC Winter Weather Statement and map concerning the chances of having .25: of ice or greater - not much.  Only expect .1-.2" freezing rain overnight and tomorrow morning mainly.

DESPITE THE RETREATING HIGH AND NOT VERY STRONG WARM NOSE WITH  FLAT SYSTEM... ARCTIC/SHALLOW AIR MASS IS EXPECTED TO HOLD STRONG AND COULD REPRESENT THE THREAT OF ICING FROM THE WRN CAROLINAS INTO THE NRN MID-ATL STATES. ITS THE CORRIDOR WEST OF I95 THATS MOST WORRISOME ESPECIALLY FROM WRN NC THROUGH SWRN VA INTO THE DC/BAL AREAS AND POSSIBLY EXTENDING INTO SERN PA. WPC GENERALLY FOLLOWED THE GFS HERE ON QPF AND A BLEND OF 12Z THERMAL PROFILES FOR A .10 TO .25 ACCUMULATIONS FROM CLT TO PHL

Finally, the NWS Advisory Text if you click to read more. Out here. Be safe.

Thursday, February 26, 2015

Snowfall / Report Map

NWS GSP Snow Reports

Thief in the Night is Gone Baby Gone


It went thump overnight but not as much as needed to see 6" area wide.  Reports aren't in yet this AM (officially) but 4-5" is more common around most of the central/NW Piedmont. Measured 4.75 at our farm but it is also snowing again moderately. 

This too shall pass. My headline sticks, what you see is what you get with perhaps a dusting on top of that.
The storm is still cranking up in Virginia and East from the Triangle to the coast, but moving rapidly east northeast and will be off the coast by midmorning.

Seems like most places struggled to reach six-inch mark not due to lack of precipitation but because of marginally cold air - standard liquid to snow ratio is .10 of precip makes 1"  of snow. Around   CLT metro saw reports of rain and sleet mixing in so they were probably averaging more of about 6 to 1 ratio which makes a big difference.

 You can see from my photos and probably from your window that the snow was heavy and there aren't tens of  thousands without power across the state and 2000 in Rowan last I saw. 



I'm off to be a nerd and measure snowfall at some other places around here so I have no more time for you right now.  I would appreciate it if you would leave a comment on Facebook or my blog telling me how much snow and where measured. Don't worry mom, you don't need to, I'll text you.

Be safe. Enjoy the snow. The courthouses in Rowan and Davie County are closed so be careful out. There could be lawyers lurking anywhere...




Wednesday, February 25, 2015

Rare - Heavy Snow Rates of 1-2" per Hour

 The Storm Prediction Center (SPC)  in Oklahoma issues mesoscale discussions for heavy winter precipitation. Typically we see the above kind of weather highlight / discussion during possible tornado watches and other severe weather events. 

They issued this not too long ago - 8PM - talks about the heavy snow rates you are seeing outside your window now. One possibly 2+ inch snow rates per hour for a few hours. 

   MESOSCALE DISCUSSION 0100
   NWS STORM PREDICTION CENTER NORMAN OK
   0655 PM CST WED FEB 25 2015

   AREAS AFFECTED...PORTIONS OF NRN SC AND CNTRL NC

   CONCERNING...HEAVY SNOW 

   VALID 260055Z - 260700Z

   SUMMARY...A RAIN/SNOW MIX ACROSS NRN SC SHOULD TRANSITION TO ALL
   SNOW AND SHIFT NORTHEAST INTO CNTRL NC THROUGH 07Z. SNOWFALL RATES
   OF 1 IN/HR WILL BE LIKELY...WITH LOCALLY HIGHER RATES POSSIBLE.

   DISCUSSION...00Z SFC ANALYSIS INDICATES A LOW PRESSURE AREA OVER THE
   NRN GULF OF MEXICO...AND A WEAKENING AREA OF HIGH PRESSURE ACROSS
   ERN NC/VA. A SHORTWAVE TROUGH OVER THE LOWER MS RIVER VALLEY
   EMBEDDED WITHIN BROADER TROUGHING ACROSS THE ERN TWO-THIRDS OF THE
   CONUS WILL CONTINUE MOVING NEWD THROUGH THE OVERNIGHT HOURS. A BROAD
   AREA OF PRECIPITATION ASSOCIATED WITH THE SHORTWAVE TROUGH AND SFC
   LOW EXTENDS FROM MUCH OF THE DEEP SOUTH INTO NC/SC.

   OBSERVATIONS ACROSS NRN SC AS OF 00Z INDICATE NEAR-FREEZING SFC
   TEMPERATURES...AND RECENT NSSL MPING REPORTS INDICATE A RAIN/SNOW
   MIX IS BEGINNING TO TRANSITION TO ALL SNOW AS DYNAMIC COOLING OF THE
   LOW/MID-LEVELS CONTINUES. AS THIS PRECIPITATION MOVES NEWD INTO
   CNTRL NC WHERE SFC TEMPERATURES REMAIN ABOVE FREEZING...
   COOLING AND MOISTENING OF THE DRY SFC-700 MB LAYER EVIDENT IN THE
   00Z GSO SOUNDING WILL OCCUR. THIS WILL SUPPORT A TRANSITION FROM A
   RAIN/SNOW MIX TO ALL SNOW ACROSS CNTRL NC THROUGH 07Z. STRONG
   LOW-LEVEL WAA AND FRONTOGENETICAL FORCING WILL SUPPORT HEAVY SNOW
   WITH RATES OF 1 IN/HR LIKELY. BASED ON UPSTREAM OBSERVATIONS FROM
   NRN MS/AL/GA...AND SREF PROBABILITIES...LOCALLY HIGHER SNOWFALL
   RATES OF 2+ IN/HR WILL BE POSSIBLE.

   ..GLEASON.. 02/26/2015


   ATTN...WFO...RAH...RNK...CAE...GSP 

FINAL FORECAST: N.C. Piedmont 6"+ Tonight - Thurs AM

Quick and dirty: Rowan / Davie County / NC Piedmont will have 6 inches of snowfall with higher amounts likely closer to Charlotte averaging 8 inches. Banding of snow will be a major player as heavier amounts will be seen. Deformation zone could occur early Thursday morning and add 1 to 2 inches of additional snow which is likely on the north east side of the Piedmont. This is very similar (yet better...) to the National Weather Service forecast from all 3 WFO's that forecast as well as WPC thoughts as shown on snow progs below.

So, 6 to 8 inches overall is a safe bet - as usual with heavier and potentially convective precip, snow amounts will vary within small distances.


Generally, only change has been a small northward movement of low / precip and corresponding increase in precip amounts.