OceanStWx Posted December 9, 2012 Share Posted December 9, 2012 Yeah, I think if frozen is a problem here it will be ZR not snow for sure. I'm surprised there's no WWA from GYX, even if its only 1" of snow... Where is the patience? Link to comment Share on other sites More sharing options...
OceanStWx Posted December 9, 2012 Share Posted December 9, 2012 Ouch... That is KGNR at 20z tomorrow(!). The cold air never gets eroded according to the NAM. Link to comment Share on other sites More sharing options...
ineedsnow Posted December 9, 2012 Share Posted December 9, 2012 looks like alot of zr Ouch... That is KGNR at 20z tomorrow(!). The cold air never gets eroded according to the NAM. Link to comment Share on other sites More sharing options...
weatherMA Posted December 9, 2012 Share Posted December 9, 2012 Where is the patience? LOL. Thanks for all your hard work. I'm just an impatient Link to comment Share on other sites More sharing options...
OceanStWx Posted December 9, 2012 Share Posted December 9, 2012 LOL. Thanks for all your hard work. I'm just an impatient It is being typed up as I type this, so legally I'm allowed to say there will be winter headlines up, including warnings for the western Maine mountains. I'm actually just arriving for the evening shift, so I'm still sorting through the data and coming up with my own thoughts. However, first blush this looks pretty nasty. There is some awfully cold air lurking on just the other side of the St. Lawrence. Link to comment Share on other sites More sharing options...
weatherMA Posted December 9, 2012 Share Posted December 9, 2012 It is being typed up as I type this, so legally I'm allowed to say there will be winter headlines up, including warnings for the western Maine mountains. I'm actually just arriving for the evening shift, so I'm still sorting through the data and coming up with my own thoughts. However, first blush this looks pretty nasty. There is some awfully cold air lurking on just the other side of the St. Lawrence. Thanks for the update. I appreciate it. Keep us updated when you can and I look forward to reading the new update from GYX. The 18z NAM is pretty cold at the low levels...keeps even some low elevations in CNH below freezing through 15z tomorrow! This is near Plymouth at 15z, wow. Link to comment Share on other sites More sharing options...
OceanStWx Posted December 9, 2012 Share Posted December 9, 2012 Thanks for the update. I appreciate it. Keep us updated when you can and I look forward to reading the new update from GYX. The 18z NAM is pretty cold at the low levels...keeps even some low elevations in CNH below freezing through 15z tomorrow! This is near Plymouth at 15z, wow. I think our forecast looks pretty good based off the brief interrogation I've done so far. Noticing a big jump in ZR probs (both lasting for 3 hours or more and falling at a rate of 0.05"/hr) on the 15z SREF run. Going from broad 10% area to greater than 30% for part of the northern CWA. If that trend continues, look out. Link to comment Share on other sites More sharing options...
powderfreak Posted December 9, 2012 Author Share Posted December 9, 2012 Ouch... That is KGNR at 20z tomorrow(!). The cold air never gets eroded according to the NAM. Yikes... that looks like what, 45F at 4,000ft and sub-freezing at the surface? That's pretty wild. Link to comment Share on other sites More sharing options...
dendrite Posted December 9, 2012 Share Posted December 9, 2012 I think our forecast looks pretty good based off the brief interrogation I've done so far. Noticing a big jump in ZR probs (both lasting for 3 hours or more and falling at a rate of 0.05"/hr) on the 15z SREF run. Going from broad 10% area to greater than 30% for part of the northern CWA. If that trend continues, look out. Yeah...looks good for a period of decent icing in the northern zones. That is a hell of a 2m gradient on the 18z NAM for tomorrow. Low 60s into SE NH and U30s for central Merrimack Co. Link to comment Share on other sites More sharing options...
powderfreak Posted December 9, 2012 Author Share Posted December 9, 2012 This seems about right for the zone forecast in this area from BTV....I still prefer the old school zones to the newer point and click forecasts. It just sums it up better in the zones, rather than paragraphs of: snow before 1am, then snow and sleet with a chance of freezing rain between 1-2am, then snow sleet and freezing rain from 2am-5am, then sleet and freezing rain with a chance of snow after 5am, etc. Tonight: Snow likely until midnight...then snow or sleet or freezing rain after midnight. Snow and sleet accumulation of 1 to 3 inches. Ice accumulation of up to two tenths of an inch. Lows in the mid 20s. Southeast winds 10 to 15 mph. Gusts up to 30 mph after midnight. Chance of precipitation near 100 percent. Monday: Rain or freezing rain in the morning...then rain in the afternoon. Highs in the lower 40s. Southeast winds 10 to 15 mph with gusts up to 30 mph. Chance of precipitation near 100 percent. Monday Night: Rain or snow until midnight...then a chance of snow after midnight. Snow accumulation a dusting to 2 inches. Lows in the lower 20s. West winds 10 to 15 mph with gusts up to 25 mph. Chance of precipitation 90 percent. Link to comment Share on other sites More sharing options...
dryslot Posted December 9, 2012 Share Posted December 9, 2012 Probably can fill in GYX's based of of CAR Link to comment Share on other sites More sharing options...
OceanStWx Posted December 9, 2012 Share Posted December 9, 2012 Yikes... that looks like what, 45F at 4,000ft and sub-freezing at the surface? That's pretty wild. Nearly +7 at 3200 ft...ha. That almost looking like some of those crazy Oklahoma freezing rain soundings. There is actually some positive elevated CAPE showing up in that sounding. Link to comment Share on other sites More sharing options...
weatherMA Posted December 9, 2012 Share Posted December 9, 2012 Link to comment Share on other sites More sharing options...
dryslot Posted December 9, 2012 Share Posted December 9, 2012 WWA coastal plain,and WSW are out foothills and mtns Link to comment Share on other sites More sharing options...
MaineJayhawk Posted December 9, 2012 Share Posted December 9, 2012 I do not approve. Link to comment Share on other sites More sharing options...
OceanStWx Posted December 9, 2012 Share Posted December 9, 2012 Yeah...looks good for a period of decent icing in the northern zones. That is a hell of a 2m gradient on the 18z NAM for tomorrow. Low 60s into SE NH and U30s for central Merrimack Co. Our local WRF is doing similar. 65 for BOS while only 42 at PSM. Never takes places like WVL above 34 tomorrow. It has a very interesting evolution (one that I happen to buy based of past experience). It keeps that marine air across the coastal plain, running from about Falmouth, ME to the SW by CON then turning N/S along the Monadnocks. Meanwhile, subfreezing air remains locked in the interior into tomorrow. Along the coast temps actually fall tomorrow, as the coastal front drifts back east, while the main warm front advances through Mass. That Falmouth to CON RA/SN line is almost always there in these SWFE. Link to comment Share on other sites More sharing options...
OceanStWx Posted December 9, 2012 Share Posted December 9, 2012 That Falmouth to CON RA/SN line is almost always there in these SWFE. You can see it on the snowfall maps posted above, maybe just a hair south of that I could see some snowfall before things get sloppy. Link to comment Share on other sites More sharing options...
dryslot Posted December 9, 2012 Share Posted December 9, 2012 I do not approve. I guess you stay in the dark........... Link to comment Share on other sites More sharing options...
MaineJayhawk Posted December 9, 2012 Share Posted December 9, 2012 I guess you stay in the dark........... Curse my tropical location! Link to comment Share on other sites More sharing options...
ctsnowstorm628 Posted December 9, 2012 Share Posted December 9, 2012 Yeah, I'm liking 1-3" before a switch over around 9z tomorrow morning...with a possible prolonged period of ZR above 900ft-ish. I'd say we switch over to plain rain and 14z-15z, and get up into the upper 30's before crashing between 0z-3z late tomorrow evening. Maybe another D-2" on the back end as well depending on the timing of that last wave. Link to comment Share on other sites More sharing options...
OceanStWx Posted December 9, 2012 Share Posted December 9, 2012 This is somewhat concerning too. The image above is the NAM op PWAT standardized anomalies (was representative of both the GFS and GEFS too). Basically showing +2 SD, approaching +3, anomalies with respect to PWAT values across NNE. Seems totally reasonable to me, given the orientation of developing convection across the Mississippi Valley right now. The development of convection there will promote positive PV anomalies in the midlevels thanks to diabatic heating. These PV anomalies (just like the upper levels) will induce a cyclonic circulation around them. This means a SW/NE line of convection will favor increased SW winds ahead, and pull more moisture northward. Our forecast is actually on the low end of QPF guidance. So this could be something to watch for as we head into the night. Link to comment Share on other sites More sharing options...
Arnold214 Posted December 9, 2012 Share Posted December 9, 2012 I think our forecast looks pretty good based off the brief interrogation I've done so far. I'm glad you approve! Link to comment Share on other sites More sharing options...
OceanStWx Posted December 9, 2012 Share Posted December 9, 2012 I'm glad you approve! It is your mess I get to clean up after all. Link to comment Share on other sites More sharing options...
OceanStWx Posted December 9, 2012 Share Posted December 9, 2012 Here is an example of the PV anomaly from the 18z NAM. This cross section is cut roughly NW to SE from MCI to ATL. The convection just east of the Mississippi around 03z tonight will induce high PV around 700 mb (shaded above 1.5 PVU). Link to comment Share on other sites More sharing options...
dryslot Posted December 9, 2012 Share Posted December 9, 2012 This is somewhat concerning too. The image above is the NAM op PWAT standardized anomalies (was representative of both the GFS and GEFS too). Basically showing +2 SD, approaching +3, anomalies with respect to PWAT values across NNE. Seems totally reasonable to me, given the orientation of developing convection across the Mississippi Valley right now. The development of convection there will promote positive PV anomalies in the midlevels thanks to diabatic heating. These PV anomalies (just like the upper levels) will induce a cyclonic circulation around them. This means a SW/NE line of convection will favor increased SW winds ahead, and pull more moisture northward. Our forecast is actually on the low end of QPF guidance. So this could be something to watch for as we head into the night. Interesting, Will have to see how that unfolds Link to comment Share on other sites More sharing options...
OceanStWx Posted December 9, 2012 Share Posted December 9, 2012 Interesting, Will have to see how that unfolds Basically this kind of set up is perfect for transporting moisture into the Northeast on SW flow aloft. If you were looking for backside snows, moisture would be more likely shunted east and QPF could be expected to be lower. Conversely, a more N/S line of convection would be more likely to throw precip back to the NW. So convection to our S doesn't necessarily rob your moisture, it may just favor displacing it elsewhere. This happens to look favorable for our region, precip-wise. Link to comment Share on other sites More sharing options...
CT Rain Posted December 9, 2012 Share Posted December 9, 2012 Basically this kind of set up is perfect for transporting moisture into the Northeast on SW flow aloft. If you were looking for backside snows, moisture would be more likely shunted east and QPF could be expected to be lower. Conversely, a more N/S line of convection would be more likely to throw precip back to the NW. So convection to our S doesn't necessarily rob your moisture, it may just favor displacing it elsewhere. This happens to look favorable for our region, precip-wise. Meanwhile... upstairs on the dynamic tropopause you can see the anticyclone PV anomaly growing and bulging north on the GFS. Here is the 12z initialization and 24 hour forecast. The strengthening gradient ahead of the cyclonic PV anomaly over the GL is helping strengthen the jet streak and in turn you're able to crank up the QG forcing over the area more broadly. Link to comment Share on other sites More sharing options...
dryslot Posted December 9, 2012 Share Posted December 9, 2012 Basically this kind of set up is perfect for transporting moisture into the Northeast on SW flow aloft. If you were looking for backside snows, moisture would be more likely shunted east and QPF could be expected to be lower. Conversely, a more N/S line of convection would be more likely to throw precip back to the NW. So convection to our S doesn't necessarily rob your moisture, it may just favor displacing it elsewhere. This happens to look favorable for our region, precip-wise. So in theory, Some of these qpf totals could be underdone then? Link to comment Share on other sites More sharing options...
powderfreak Posted December 9, 2012 Author Share Posted December 9, 2012 This is somewhat concerning too. The image above is the NAM op PWAT standardized anomalies (was representative of both the GFS and GEFS too). Basically showing +2 SD, approaching +3, anomalies with respect to PWAT values across NNE. Seems totally reasonable to me, given the orientation of developing convection across the Mississippi Valley right now. The development of convection there will promote positive PV anomalies in the midlevels thanks to diabatic heating. These PV anomalies (just like the upper levels) will induce a cyclonic circulation around them. This means a SW/NE line of convection will favor increased SW winds ahead, and pull more moisture northward. Our forecast is actually on the low end of QPF guidance. So this could be something to watch for as we head into the night. Yeah some of the models over the past two days have been printing 2-3" stripes from the southern tier/central NY state up through central VT/NH. This looks juicy. Link to comment Share on other sites More sharing options...
powderfreak Posted December 9, 2012 Author Share Posted December 9, 2012 The 18z NAM really has a good burst of snow/sleet into NH/ME... It sneaks in some pockets of 0.35-0.5" QPF with H85s of like -2C to -4C. Not sure what above that looks, but I'm guessing that's a pretty good 3 hour burst of snow/sleet for the northern half of NH, and it continues in the next panel in western Maine. Wonder if some spots start pulling out some solid 1"/hr snows for a bit prior to changeover. Link to comment Share on other sites More sharing options...
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