packfan98 Posted March 5, 2014 Share Posted March 5, 2014 hr 36: ULL is about 50 miles nw of it's earlier run. Link to comment Share on other sites More sharing options...
burgertime Posted March 5, 2014 Share Posted March 5, 2014 18z NAM looks colder to me than 12z. Link to comment Share on other sites More sharing options...
packbacker Posted March 5, 2014 Share Posted March 5, 2014 Hour 33 on the nam is much colder at 850. Snow in mountains when the 12z had the 0c line in VA. 18z NAM looks colder to me than 12z. Looks colder for sure, the ULL is really doing it's thing with the pockets of 850's below 0. Link to comment Share on other sites More sharing options...
packfan98 Posted March 5, 2014 Share Posted March 5, 2014 The surface low off of Myrtle beach is definitely stronger. More robust precip shield over NC. Everything looks a little north of 12z. Link to comment Share on other sites More sharing options...
packfan98 Posted March 5, 2014 Share Posted March 5, 2014 What looks like a deformation band sits over I-85 for a while. Too bad it's liquid! Heartbreaking! Link to comment Share on other sites More sharing options...
burgertime Posted March 5, 2014 Share Posted March 5, 2014 Still not going to get the job done for snow it looks like. GSO north gets some nasty ZR at the onset. Link to comment Share on other sites More sharing options...
packbacker Posted March 5, 2014 Share Posted March 5, 2014 The surface low off of Myrtle beach is definitely stronger. More robust precip shield over NC. Everything looks a little north of 12z. The Euro has the ULL further south than the NAM, think the NAM will correct tonight/tomorrow, curious to see how that affects everything. Link to comment Share on other sites More sharing options...
Blue_Ridge_Escarpment Posted March 5, 2014 Share Posted March 5, 2014 CAD areas of foothills and triad get real real icy on this run of the NAM. Basically I-40 Link to comment Share on other sites More sharing options...
Cold Rain Posted March 5, 2014 Share Posted March 5, 2014 Nam drops a huge amount of precip. I wonder how much it's overdoing that. Link to comment Share on other sites More sharing options...
superjames1992 Posted March 5, 2014 Share Posted March 5, 2014 That's a big change out of the NAVGEM, Pack. Prior runs were absolutely torching. Link to comment Share on other sites More sharing options...
packfan98 Posted March 5, 2014 Share Posted March 5, 2014 YOU MUST READ!!!! NWS Raleigh AFD: .SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...AS OF 300 PM WEDNESDAY......A WINTRY MIX IS LOOKING MORE LIKELY... MAINLY OVER THE NORTHWESTPIEDMONT THURSDAY NIGHT INTO EARLY FRIDAY... THIS INCLUDES THEPIEDMONT TRIAD AND ROXBORO...... RAIN IS EXPECTED ELSEWHERE... BUT MAX MIX WITH A LITTLE SLEETAND FREEZING RAIN THURSDAY EVENING FROM ALBEMARLE TO RALEIGH TOROCKY MOUNT...THE MID/UPPER LOW CURRENTLY EXITING THE TEXAS PANHANDLE IS FORECASTTO TAKE A SOUTHERLY TRACK ALONG THE GULF COAST THURSDAY NIGHT...THEN SLOWLY TURN ENE ALONG THE SOUTH CAROLINA COAST FRIDAY...EXITING THE NC FRIDAY EVENING. THIS SOLUTION IS A PREFERRED BLEND OFTHE 12Z/GFS/ECMWF/UKMET. THE LATEST MODEL GUIDANCE HAS BEEN TRENDINGCOLDER WITH LESS OF A WARM NOSE IN THE MID-LEVELS BACK OVER THENORTHWEST PIEDMONT FOR THE MAIN PART OF THE EXPECTED PRECIPITATIONEVENT. FOR THE SURFACE LOW PRESSURE DEVELOPMENT/TRACK EXPECTED FROMTHE GULF OF MEXICO NORTHEAST JUST OFFSHORE THE SC/NC COAST THURSDAYNIGHT AND FRIDAY... IT IS HARD TO ARGUE WITH WPC`S PREFERENCE OF ABLEND OF THE 12Z/UKMET WITH THE 00Z/ECMWF AND ECMWF ENSEMBLE MEANFOR THE FORECAST SOLUTION. THERE HAS BEEN A SLOWING TREND WITH THEGUIDANCE AND CONFIDENCE HAS ALSO INCREASED WITH BETTER CLUSTERINGFROM THE ENSEMBLE PLOTS.ANOTHER CRITICAL FEATURE IS THE PRONOUNCED VERY COLD PARENT SURFACEHIGH PRESSURE THAT IS FORECAST TO BUILD FROM NEW ENGLAND DOWN THEEASTERN SEABOARD INTO NC/UPSTATE SC LATE WEDNESDAY NIGHT ANDTHURSDAY... AND BE IN PLACE THURSDAY EVENING. THIS HIGH IS OFSUFFICIENT STRENGTH (1040ISH+ MB) AND PREFERRED LOCATION NY/NEWENGLAND TO DELIVER COLD DRY AIR INTO OUR REGION AS THE STORMARRIVES. ONE QUESTION HAS BEEN HOW QUICKLY THE HIGH WILL RETREAT ANDTHIS APPEARS TO BE THURSDAY NIGHT. HOWEVER... CLASSICAL DAMMING ISEXPECTED TO UNFOLD THURSDAY EVENING AS THE MAIN PRECIPITATIONSATURATES THE COLUMN QUICKLY.IN ADDITION... THE WARM NOSE ALOFT IS ALSO CRITICAL AS MODELS HAVEBEEN TRENDING COOLER WITH TIME WITH LESS OF A WARM NOSE REACHINGWELL BACK INTO THE FOOTHILLS/BLUE RIDGE. WE WERE NOT BITING OFFTOTALLY ON THESE SOLUTIONS AS THERE IS STILL A LOT OF UNCERTAINTY.IF THESE TRENDS CONTINUE... A WINTER WEATHER ADVISORY OR EVEN AWINTER STORM WATCH MAY BE NEEDED IN THE NW PIEDMONT FOR THURSDAYNIGHT INTO EARLY FRIDAY FOR A WINTRY MIXTURE OF MOSTLY FREEZING RAINWITH EVEN SOME MEASURABLE SNOW AND SLEET. THE WARM NOSE ALOFT MAYACTUALLY EVEN VERIFY LESS INTENSE IF THE LIFT IS STRONG ENOUGH TOOFFSET THE WAA ABOVE THE NEAR SURFACE COLD NOSE. THIS MAY LEAD TO ACHANGE TO WET SNOW AT TIMES IN HEAVIER PRECIPITATION. THE TRACK OFTHE MID LEVEL LOW IS ALSO CRITICAL... AND THIS REMAINS WELL SOUTHAND EAST OF OUR REGION THIS MODEL RUN... SUPPORTING COLDER AIRALOFT.... THE NORTHWEST PIEDMONT TO ROXBORO AND OXFORD...RIGHT NOW... THE FORECAST 1000/850 AND 850/700 PARTIALS INDICATE1295-1305M/1545-1555M DURING MUCH OF THE OVERNIGHT PERIOD THURSDAY.NOMOGRAMS SUGGEST A WINTRY MIXTURE WITH MORE SNOW/SLEET THE LESS THEWARM NOSE... AND MORE IN THE WAY OF FREEZING RAIN/RAIN IF THE WARMERNOSE VERIFIES. WE WILL LOOK TO SURFACE WET BULB FORECASTS FORPLACEMENT OF THE MOST CRITICAL REGION THAT WOULD LIKELY SEE THEHIGHEST PROBABILITIES OF THE WINTRY MIXTURE/ICING. CURRENT FORECASTSINDICATE WET BULBS OF 30-32 FROM NEAR LEXINGTON TO GREENSBORO TOROXBORO THURSDAY NIGHT... AND SUB 30 POSSIBLE FROM WINSTON-SALEM ANDTHE PTI AIRPORT NORTH AND WEST. THESE WILL BE THE MOST CRITICALLOCATIONS FOR POTENTIAL WINTER WEATHER. HERE... WE WILL FORECAST AMIXTURE OF FREEZING RAIN AND SLEET... POSSIBLY WET SNOW AT TIMES.GLAZING OF ICE OF 0.1 TO 0.2 POSSIBLE... WITH SNOW AND SLEET OF LESSTHAN AN INCH. THESE ARE PRELIMINARY NUMBERS AND WILL LIKELY CHANGEAS THE STORM EVOLVES. TEMPERATURES SHOULD FALL TO NEAR THE WETBULBS... UPPER 20S TO AROUND 30. COLD AIR DAMMING SHOULD BE LOCKEDIN FOR A WHILE. HOWEVER... TEMPS SHOULD SLOWLY RISE TO NEAR OR ABOVE32 MOST AREAS... INTO THE MID TO UPPER 30S. UNLESS PRECIPITATIONRATES CONTINUE HEAVY... PRECIPIATION SHOULD CHANGE TO RAIN. WET SNOWCAN NOT BE RULED OUT IN HEAVIER BANDS....TO THE SOUTH AND EAST INCLUDING ALBEMARLE TO RALEIGH TO ROCKYMOUNT... RAIN IS EXPECTED THAT MAY MIX WITH A LITTLE SLEET ORFREEZING RAIN THROUGH MIDNIGHT... THEN CHANGE TO RAIN AS TEMPS RISESLOWLY OVERNIGHT. WET BULBS NEAR 32 DO SUPPORT SOME GLAZING... BUTONLY ON ELEVATED SURFACES. RAINFALL RATES SHOULD LIMIT ICING. LOWS31-32... RISING TO 34-35 OVERNIGHT. RAIN IS EXPECTED FRIDAY. MAY BESOME WET SNOW (NON ACCUMULATING) DUE TO THE WET GROUNDS DURING HEAVYPRECIP BANDS/RATES FRIDAY. HIGHS 37-44.ALL RAIN IS EXPECTED FROM ROCKINGHAM TO LILLINGTON TO WILSONSOUTHWARD DURING THE EVENT WITH WET BULBS LIKELY REMAINING ABOVE 33AND RISING TOWARD 40 OVERNIGHT. RAIN FRIDAY... HIGHS IN THE 40S.THE BOTTOM LINE AT THIS POINT IS THAT WE ARE CONFIDENT THAT THENORTHWEST PIEDMONT HAS THE BEST CHANCE OF A WINTRY MIX... WITHLESSER CHANCES CLOSER TO THE TRIANGLE AND NIL POINTS SOUTH AND EASTOF THE ROCKINGHAM TO RALEIGH TO WILSON AREAS.MODELS HAVE TRENDED TOWARD MORE OF A WINTRY MIX... WITH MOREFREEZING RAIN AND EVEN SNOW/SLEET OVER THE NW PIEDMONTCONFIDENCE IN THE PREDOMINATE PRECIP TYPE AND POSSIBLE ACCUMULATIONSIS STILL LOW GIVEN SOME OF THE DIFFERENCES IN THE EXTEND OF THEDAMMING... THE SURFACE/850MB LOW TRACK... AND WESTERNEXTENT/STRENGTH OF THE WARM NOSE.PRECIPTATION SHOULD END LATE FRIDAY BUT TEMPERATURES SHOULD REMAINABOVE FREEZING FRIDAY AFTERNOON AND NIGHT KEEPING ADDITIONALPROBLEMS WITH FREEZING VERY LOW. Link to comment Share on other sites More sharing options...
GaWx Posted March 5, 2014 Share Posted March 5, 2014 As has just been noted by others, 18Z NAM is colder. At 850/925 it si colder. It has 925 near to below 0C for much of the time ATL-AHN with heavy (1"+ )precip. And now we have a colder trend perhaps? Be wary! This is a very rare setup for early March. Link to comment Share on other sites More sharing options...
packbacker Posted March 5, 2014 Share Posted March 5, 2014 NWS Raleigh AFD: ie...get ready triad and NW NC up to ROA, if the Euro is off by 1-2 degrees this could get ugly by early Friday morning. Can you imagine if that HP was 50 miles west and didn't scoot out as fast. Link to comment Share on other sites More sharing options...
jburns Posted March 5, 2014 Share Posted March 5, 2014 Is Canadian showing wintry precip at GSO? If so, howuch? If more than .25, then I believe nam, gfs, and can would all give GSO warning criteria between about midnight toe row night and mid/late morning Friday. TW I'll look forward to frolicking in the snow with my herd of unicorns. The snow slows down the hydra so it's a lot safer. Link to comment Share on other sites More sharing options...
MillerA Posted March 5, 2014 Share Posted March 5, 2014 Gsp Short term /6 am Thursday morning through Friday night/... as of early Wednesday afternoon...high pressure over the northestern US will continue to build tonight under confluent upper flow...with surface ridge extending down the East Coast and at least briefly configuring cold air damming by tomorrow. Parent high weakens and slips off the New England shore tomorrow night. Associated cold wedge lingering into Friday will focus low level upglide over the forecast area ahead of southern stream shortwave developing a surface low over the eastern Gulf of Mexico...likely producing precipitation across the region late tmrw into early Friday. Wedge will slowly erode beginning Friday...with all precipitation ending Friday evening. Spread between the NAM/GFS/ec/CMC has narrowed...but minor differences are still noted which are of particular consequence due to temperatures at the surface and in the lower troposphere supportive of a winter weather threat. Differing placement of highest quantitative precipitation forecast and strength of the warm nose over The Wedge lead to vastly different ice/snow accums. Ec seems to waffle from run to run between the NAM/GFS extremes with respect to low track...but consensus at this point is for the low to ride near the Carolina coast and depart just east of the Outer Banks. All models now develop notable quantitative precipitation forecast response to deformation zone crossing the area with short wave early Friday but by this time the ridge appears to be weakening and surface temperatures warm enough for a changeover to rain that persists until precipitation ends. In terms of timing...trends seem to be for the event to be pushed later into Friday. Ec/NAM soundings feature a more significant warm nose which could be attributed to the more onshore track and lower pressure of the surface low. These scenarios would result in mainly freezing rain in the presence of surface temperatures below 0c. GFS is colder in llvls and has a weak warm nose...giving more sleet or even snow. Blended thermal profiles were used with the top-down technique to arrive at precipitation type. Surface temperatures are expected to remain near raw model values for the duration of The Wedge...and bottom out very close to freezing Thursday and Friday mrngs over much of the forecast area...allowing for modest wet bulb effects in the moist environment. Rain is expected to begin spreading north across the area during the day tmrw...changing along/east of the Blue Ridge and north of I-40 to sleet and then freezing rain as the warm nose strengthens toward Friday morning. Assuming The Wedge is able to weaken Friday as currently expected...temperatures should warm enough to end the wintry precipitation. Being moderately conservative with quantitative precipitation forecast...and following the evolution outlined above...both snow and ice totals remain under Winter Storm Watch criteria for now. && Long term /Saturday through Link to comment Share on other sites More sharing options...
GaWx Posted March 5, 2014 Share Posted March 5, 2014 I'm requesting a link to NAM two meter temperatures. Would anyone mind providing it? Link to comment Share on other sites More sharing options...
packbacker Posted March 5, 2014 Share Posted March 5, 2014 I'm requesting a link to NAM two meter temperatures. Would anyone mind providing it? These are pretty good... http://www.tropicaltidbits.com/analysis/models/namconus/ Link to comment Share on other sites More sharing options...
GaWx Posted March 5, 2014 Share Posted March 5, 2014 These are pretty good... http://www.tropicaltidbits.com/analysis/models/namconus/ Thanks, Pack! Link to comment Share on other sites More sharing options...
FallsLake Posted March 5, 2014 Share Posted March 5, 2014 ie...get ready triad and NW NC up to ROA, if the Euro is off by 1-2 degrees this could get ugly by early Friday morning. Can you imagine if that HP was 50 miles west and didn't scoot out as fast. I still think we have a small chance of getting something significant here in the RDU area. As RAH has stated we'll be right on the line for wintery precip. Really hoping the cold influx from up north is colder than modeled (..from snow pack). That 1-2 degrees would put us right in the middle of the game. Link to comment Share on other sites More sharing options...
Marion_NC_WX Posted March 5, 2014 Share Posted March 5, 2014 I think given the very borderline temps GSP is doing a good thing keeping this conservative and not posting any products in the afternoon package...because I can tell you if they went broad-brush and issued Winter Storm Watches for most of their NC Counties, a lot of people and groups of people would over-react and then blame them if it didn't verified. This gives them 2 more model runs and then they can pull the trigger tomorrow AM. Link to comment Share on other sites More sharing options...
GaWx Posted March 5, 2014 Share Posted March 5, 2014 These are pretty good... http://www.tropicaltidbits.com/analysis/models/namconus/ Wow, these maps' two meters look too warm to me overall. Link to comment Share on other sites More sharing options...
packbacker Posted March 5, 2014 Share Posted March 5, 2014 Wow, these maps' two meters look too warm to me overall. Well the NAM is the furthest north with the ULL so would think that is playing some factor in it? Link to comment Share on other sites More sharing options...
GaWx Posted March 5, 2014 Share Posted March 5, 2014 Well the NAM is the furthest north with the ULL so would think that is playing some factor in it? I mean that on 3/6 they look too warm. Example: how does it warm 12 degrees at CLT tomorrow between 7 AM and 1 PM under cloudy skies and great CAD?? Link to comment Share on other sites More sharing options...
packfan98 Posted March 5, 2014 Share Posted March 5, 2014 Uhh...the 4k nam spit out 2.9" qpf and over 1.5" freezing rain for GSO! Link to comment Share on other sites More sharing options...
deltadog03 Posted March 5, 2014 Share Posted March 5, 2014 As has just been noted by others, 18Z NAM is colder. At 850/925 it si colder. It has 925 near to below 0C for much of the time ATL-AHN with heavy (1"+ )precip. And now we have a colder trend perhaps? Be wary! This is a very rare setup for early March. It def. is colder.. I truly think we have to watch out for that ULL when that heavy band comes through N and CGA Link to comment Share on other sites More sharing options...
packbacker Posted March 5, 2014 Share Posted March 5, 2014 4km has several hours of ice for triad.. Link to comment Share on other sites More sharing options...
packbacker Posted March 5, 2014 Share Posted March 5, 2014 18z RGEM came in much colder and RGEM runs a little warm too. Looking more and more likely the triad and N/W NC will have something to deal with, not sure of the scale though. Link to comment Share on other sites More sharing options...
BIG FROSTY Posted March 5, 2014 Share Posted March 5, 2014 12z Euro gives me .63qpf which looks to be snow/sleet then .17 rain at the end. Link to comment Share on other sites More sharing options...
mackerel_sky Posted March 5, 2014 Share Posted March 5, 2014 I mean that on 3/6 they look too warm. Example: how does it warm 12 degrees at CLT tomorrow between 7 AM and 1 PM under cloudy skies and great CAD??Really, it's the high March sun angle/ radiation getting through! With no rain till late tomorrow , I would not be surprised to get to 45-50 imby, then drop to upper 30s after precip starts. Link to comment Share on other sites More sharing options...
superjames1992 Posted March 5, 2014 Share Posted March 5, 2014 That was a very bullish AFD by NWS RAH. I really didn't expect the mention of wet snow and the mid-levels being colder than progged. Link to comment Share on other sites More sharing options...
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