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Friday, February 19, 2010

It goes beyond the 23rd...

2/22 - ok its 10pm and snowing at 34 degrees and 87rh. Not much more room for cooling although obs in Trenton are below freezing. I'm still doubtful it gets cold enough or snows hard enough to stick to the streets.

12z Looks like NAm is too late (no precip til 7am), UKMET gets it right, cmc too slow, gfs right. euro doesnt have the resolution to tell

So it looks like wet snow, light amounts overnight. UK met keeps it cold, nam warms it. CMC keeps us on the line through 72 hrs. Euro has right thicknesses (under 540) and keeps us under freezing, but barely, for the next week. GFS has right thicknesses, but goes to .8 at 850 for 6hrs on Wed. Its amazing the different timing, strengths and tracks being taken.

Beyond Wed is going into another thread.


Euro - still keeps it cold enough at 850 to be all snow, so long as boundary layer is under 35.
UKMET - up to 72 hrs, looks like snow starts 6-12z tuesday and comes down hard later that day. Again, 850 line south of LI, so only real warm boundary layer should be causing rain
CMC - keeps 850 line on CT coast until 12z wed when its 992 low tracks up to nyc. from there it heads to buffalo, keeping us warm. But then the third low comes up and tracks around montauk, to Springfield, to Albany to Scranton to N NJ. Thickness lines after wed are clearly snow, but BL temps are in the 30's
WRF - secondary goes se, minor snow, then another forms and pushes 850 line and thickness line just on the coast. Keeps dxr mostly around .5 - (1.5) so its right on the r/s line. Wednesday is the real start and the phasing with the third system not until later thurs. If that happens, should be snow as the 540 thickness line runs from obx to ack. The 12z was much warmer in the beginning though.
GFS -18z - this just doesnt happen. The secondary stays south enough that the 850 line mostly stays south of us, except at 6z wed. Thickness stays south of us. It precips for a long time. The third storm phases well out to sea, then loops around into boston and sits there for friday and saturday, at 976! Snow reaching all the way to DXR from this! nuts.
12z - similar to 18z, but does not stick in bos as long. Both runs have dxr very close to r/s line and it depends on BL temps.
GFS ENS - using dominant precip type, only rain for them is at 18z on wed. rest is snow on 18z run. SREF is mostly rain though.

Precip amounts. Wrf has over 2 inches and thats just tues and weds. Gfs looks similar. The max it can do is 60 hours and this event will be much longer. The accuweather gfs has most of CT getting at least 2.5 inches of precip this week, with eastern parts closer to 3 and parts of Mass at 4. snowfall map has parts of vt, ma and ny with over 24 inches while ct has some... see above.

2-21 0z/6z

UKMET - holds off snow until tuesday night as first one goes to lakes and peters out. Second comes up coast for Tues nite and sits over us wed-fri

Euro - Moisture comes in mon nite as snow. 1000 low reforms off delmarva on tues nite, with dxr staying under freezing at 850. Low moves due north over BDL on Wed nite, then due East on Thurs nite when the third impulse catches up with it and it bombs out to 988 around the BM. Then it retros back into Mass on Fri nite. to Alb Sat nite. Model output for 850 temps all under 850 for dxr and RH from tues nite onward is in the upper 80's to 90's.

CMC - snow moves in Tues morn as secondary forms, secondary goes right up over NYC and hudson on Wed, putting us in the warmer sector. then it cuts off, and cold air pours in, putting us in the cold sector by wed nite. Then it just spins around NY/W New england for a few days with impulses coming in and going out, all under 0 at 850.

wrf - 6z - now has first storm dying with second forming to our south and heading ne, missing us for tuesday, but retrograding on wednesday, with us in the under 0 at 850 sector.
0z was similar non event as it did not retrograde

gfs -6zz holds off snow until tues afternoon, runs secondary out around li into RI. keeps weak until third system catches it over Bm, then pivots into CCOD area on Friday at 988. we are below 0 at 850 through the week, but surface temps are around 30-35.
0z run brings snow in tues morn, with secondary running to BDL, wed morn at 992, spinning and petering out, with third system coming in, but further east over BM and east of CCod and doing a loop over Ccod. see precip output for 6z above

2-20 - models still a mess, with some putting nothing down for the first, but loading the second, some snow, some rain. the 0z run 2-21 has a huge amount of precip 3 inches in CT. see above. Its not all snow, maybe even very little. The dgex 18z also had a lot of snow on the ground in the hills NW CT. like over 24 inches. Problem remains too much warm air to start and low is too close (actually on top of us)

2-19 The afternoons runs for today show that the 23rd storm is trouble to forecast. This will be difficult to describe in words but I'll try
Euro - takes low in IL (1002), splits it primary into the lakes and secondary over NC/VA on Tues. Secondary takes over somewhere off NJ, but weak (1006) on Weds. Sits around the BM on Thurs and moves NW from RI to Ontario (996) on Fri. It keeps us right on the cold side of the 850 line and 540 line, but barely and I can see how it sleets or rains instead.

UKMET goes from MO on Monday, north into lakes Tuesday, but reforms off NC/SC. Goes north to Delmarva on Wednesday and to LI/CT on Thursday(992). Would guess this is snow to rain, but can't tell how much and when the change occurs.

GFS - 18z run is facinating. Over KY,IN and IL on Monday morn. Up to the lakes as a 1000mb with snow moving in Monday night here. Secondary forms Tuesday morn off OBX with steady snow continuing. Lakes low dissapates and secondary moves just southeast of BM, with still snow on Wed morn, but lightening up, at 998. Thursday it moves NW and dissapates while another storm is forming off NC. The old storm pushes the 850 line west with it, while the new one comes up the coast and centers (992) over C May Thurs morn. Thurs afternoon it goes to Scranton (988) and sits until Saturday as it moves over New England. The deepening on Thurs afternoon brings more cold air into it, pushing the 850 line east, with precip finally ending on Saturday. So it goes from snow, to rain, to snow. However, surface temps over most of S NY, CT, MA, NJ are all above 32 for most of the time.

DGEX - keeps with the primary to lakes, secondary off coast, keeps it all snow for us on Tuesday. Breaks the weather Wed Afternoon until Thurs afternoon when another low forms over SC, never makes it to the water?? and goes to philly pushing the 540 line all the way west to PIT.

CMC - Low monday over S. IL. Primary goes to N IN on Tues, with secondary forming over delmarva as snow begins tues morn over us. Wed - Old low weakens, secondary sits off NJ by NYC and spins for a day as old low kicks it out. After moving past BM, new low and old low (still over NYC) move almost due west back to Ontario and CCOD. just as weird as GFS, but results in all snow.

GFS ENs - 18z run has low over IN on mon. fades to the lakes and secondaries on tuesday over obx. Moves over BM on Wed 1000. East of CCod, barely on thurs. Weaker low develops thurs and moves east of here friday to about portsmouth. Only has rain for 6 hrs on wednesday.

So the american models see the system coming up from the south, the CMC, UKMET and Euro don't. fun!

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