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Saturday, December 26, 2009

New Years Eve and weekend after

12/31 - after having the models still disagree yesterday, all have come around on 0z runs today to have the second storm form way too far out to sea. Some (euro) still produce moisture enough to snow, while others don't. Instead of pivoting the low into cape cod, they now just have it going into canada. The exception is WRF 6z run which still has low on sunday in gulf of maine. Result is only snow for the first storm here as radar looks good. Second storm may bring flurries here and only wrf and cmc has precip progged for vt. The euro doesn't prog precip, but its RH maps support snow through sunday. Amazingly, the WRF, CMC, UKMet and GFS still don't have much snow on the first one, if any, and the mets are calling for 2-5 inches. Good for them unless this dries up again as radar looks good for 2 inches at least. Other thing is that they all have the low closing over us, which should have resulted in some dynamics to produce precip with the available moisture.

12/29 afternoon runs -
CMC - 1st still misses. 2nd has upper energy catch up and stalls it, but further out to sea than gfs. Still has us at the southern edge of the snow, but pounds north of MA. Snows mostly friday afternoon thru sunday. Goes to 962mb in gulf of maine and spins around until Monday.
Euro - weaker first system with snow. Second catches up but off shore, then spins back into Maine then out on Sunday. Keeps all of NE in the right RH% for snow.
Ukmet - up to 72 hrs, does not have anything through 12z friday. Profile supports all snow, as does CMC and EURo. On longer map, it bombs out just east of the 40/70 to 976 on Sat mornand spins back to Cape cod on Sunday morn.
DGEX looks like it bombs out over the benchmark, rotates around the gulf of maine down to 970mb, back over ACK on sunday nite then out. But the precip field only reaches back to hartford
12z gfs pushes first low east of benchmark on thurs nite, with precip after midnite, as rain. Waits until Saturday, well off cape cod for the other energy to catch up and it bombs out, pivoting into Maine and the gulf of maine/ Tries to exit over the cape, but dissapates. The precip field is not very far west, nor south. It does reach 976 while over Maine, but only brings precip to north of midway up vt, nh and me. Essentially a non event for W. CT.
18z run is much less organized with the first wave, with precip starting Fri morn, and rain line much further south and east than 12 z. Much more likely to have snow in W CT on this run.All north of CT is snow, as opposed to 12z run which had rain all the way into vt and nh. The low stalls all day Friday, literally in the sound, out to ACK. Then the second one catches up and it explodes, rotating into the gulf of maine and out over the cape again. This should crush most of new england, but the precip is not impressive
WRF/NAM - up to Friday has nothing for CT as first wave goes out to sea.
JMA is also saying out to sea, when it explodes and turns into the border of Maine, so it misses us.
Its truly amazing that 4 days out, the models (WRF and GFS) are so opposite.

12/28 morning runs

Euro - has front runner thurs nite with 540 line just s of ct. by fri nite its a 992 over RI, Sat nite its 992 over NH. So not that strong, but persistent as its caught in the upper low

CMC - first system thurs nite brushes us, second system goes off shore where it phases well out to sea. Maybe a few inches thurs nite

UKMEt - moves one storm up to the west of us

DGEX - has a 970 low just south of LI, to ACK - starts Fri and ends Mon morn. snow is off the chart - see above - should be more widespread

GFS - starts thurs nite, rains in CT and tracks over CT where it bombs to 992 and hangs out until sunday morn

JMA - goes out to sea and back into maine as a 969 low.

Summary - models everywhere and flip flopping - not sure if one or two systems, or if the first will stick around, bomb out or what. Very likely we will have snow, less likely rain, and unlikely nothing.

12/27 morning runs
Euro - forms storm over SC thurs nite, moves off cape cod fri night. Does not phase with n stream and cut off until way out to sea
CMC - forms one storm over VA thurs nite which goes out to sea with min snow. Forms another storm off FL and brings up coast off NC sat nite and just to our east, bombing out, sunday with a few inches of snow
UKMet - forms thurs nite off VA and goes out to sea (at 144) no indication of another storm following
DGEX - major 30 inch storm as it starts NEw years, gets caught in the upper low and explodes friday during the day. anywhere from 12-30 inches show up on the snow map
GFS has storm off coast of NC at noon on 12/31, going out to sea with min effects. But another forms over TN and FL and they phase Friday during the day with a 1004 right off NJ coast. That sticks around, caught by the upper low cut off, until Sun morn (180 hrs). It deepens to 992 before occluding and weakening. Would be major snow event.

Watch for weak storm to come in around New years eve, with a stronger one following . CMC has blizzard the following weekend, Euro has big noreaster. JMA and GFS jump on the 12-31 storm instead.

Correction - 12z gfs now has it in the second storm with the first one weaker. But second storm is not strong and is a little too far off thecoast. This will move back in time.

Monday 28th

Should see some light snow amounts as the artic front comes through, but nothing worth following. Watch if snow enhances near the coast as storm forms off shore. NAM and GFS has one inch forecast.

Tuesday, December 22, 2009


Haven't posted yet on this as it does not seem to be a snow event. What should happen is the storm should run to the lakes with secondary development just off the coast.

Right now, all models show this. The difference is in timing and the eastern extent of the primary low. They are waffling between bringing the low to the lakes, then east over MI and NY where it secondaries, and bringing it west of the lakes, where it dies and the secondary forms in GA and runs up the coast. The first results in precip in on Christmas eve/morn, the latter with precip Christmas night into saturday. All models have the 540 thickness line going into Canada, so it will change to rain. The models also backload the precip - meaning that all the precip falls after the 0 line at 850 crosses. This is suspect. There is a high located in Canada, sliding off to the east which puts cold damming in to play. If the precip comes early, which the mets are progging, then there will be a period of sleet and freezing rain. If we can get the secondary stronger, it could be more interesting.

19th -20th strom summary

This long tracked storm ended up originating in the gulf, with input from a shortwave and upper low from the plains. The initial gulf moisture pounded NC, VA, MD and DE, but fell mainly aloft in areas north of Philly.

In Danbury, radar echoes showed up at 8am, with the first flakes falling at 3pm, for about 15min before they shut off. They started again at 8pm, with the ground being covered by 9 and one inch by 10. The snow that fell here was mostly from the combination of the southern storm, shortwave and upper low bombing out just east of new jersey. You could watch the eye of the storm go from the Delmarva off to just south of the benchmark. Danbury ended up with 7 inches officially, but 5-6 mostly in my yard. The wind blew away a lot of the snow as it was very fine. Winds gusted at the house up to 22 mph. I had thought my call of 8 inches was conservative as the precip output on the gfs and nam were between 1.25 and 2 inches for the area. Dry air destroyed this storm for the north as Litchfield, Torrington area got 3 inches, POU got 2.

Elsewhere, LI, RI and Southeast CT had amounts up to 27 inches. Wind gusts there and on the cape were over 50mph. Much of S NJ received over 20 inches, with Roseland getting 11. Surf City, on the beach, received 20 inches. Southern NJ had both the intital moisture and moisture from the bomb off the coast.

Pictures are of snow cover as of today. Should last to Christmas Day when it will likely rain :(

Friday, December 18, 2009

12-20 part two

12-19 all 0z models showing major storm now.
0z nam bumps us down to 2 inches, but 6z back over a foot
0z GFS has atleast a foot, down to 10 inches for 6z
All models have storm rapidly deepning, tucking in around Delaware Bay, moving near or over the benchmark later.
NWS - 6-10 inches (8-14 in WSW)
AW has 6-7 inches on its alarm, but 3-6 on snow map
WU has 7-11, twc 6-12, WTNH has 8, wfsb 10-14, wvit 8-14, wcbs 6-10, wabc 3-6 (uses aw) GFS snow map pinches us off with only 6. Nam has 12-16

12-18LAtest GFS 0z precip total. Looks like at least a foot. Nam backed way off though....

Saturday, December 12, 2009

12-19 Clipper or Southern Branch

12-18 - midday. GFS finally putting snow down .25-.5 as the storm tracks just off NJ. CAN goes nuts as does wrf which has .5-.75, but the 2in line is at LI. Seems way too tight of a precip gradient and these normally shift north. Plus ratios will be higher in CT. UKMet is furthest east and is weakest. The weaker the storm, the further east. GFS Ensemble has it at the benchmark at 984. How many storms fail to produce when at the benchmark with cold air around? Just in -the HRW - with no precip further north than DE.
AW forecast for Danbury is 3-6. 4 on the weather alert. With HM calling 1-3
NWS winter storm watch of 10am says 5-10 possible
DR Mel - 4-10 with highest east ct and near shore
AW having major issues with connectivity

some pix from the morning

12-16 Euro a bit further east, but still affects us,
GFS 18z run brings right off shore with .25 to .5 inches output
CAN brings one storm out to sea, but reforms another closer to shore. That part looks like the clipper actually.
UKMET brings up to hatteras then out to sea, no effect.
JAP goes a little further east but still hits us.
Nogaps goes up to Hatteras and out to sea, no effect. Has trailing clipper system hitting on Tuesday.
NWS has 30% chance of snow on Saturday
AW has nothing

12-15 UKmet - 0z run way out to sea, 12 z run a little further north but still way out
Euro - 0z right off NJ. 12 z SC to cape cod
CAN - va capes to li. 12 z - hilton head due NE out to sea
NGaps - 0z in near nj. 12z moved east but still hits
GFS - Hangs off the coast too far. 12z moves further north but then out NE.
JAP - a little further east than yesterday, but still hits hard.
NWS - only mentioned chance of energy coming through in discussion
AW - nothing
TWC - chance of snow showers.

12- 14 - Euro onto southern stream storm phasing with northern sw, but on 12/20. GFS still out to sea. DGEX has clipper and it snows for 42 hours. Nogaps onto clipper diving in and reforming off the coast, as is the CAN for the 19th. UKMet only has southern stream and keeps well south. NWS has chance of snow on Sunday. AW has nothing.

12-13 - I see nothing anywhere

12-12 GFS and UKMET and Dgex have small clipper with 2-4 inches coming through on 12-19. Euro has no clipper but a storm over GA. Can has storm starting in TX panhandle at 144.

Friday, December 11, 2009

Drying out in December?

Here is a look at the second to last week, total precip for the week. Wow - while I don't care for dry cold air, this would be amazing if it panned out, that 95% of the country only gets under .5 inches of precip for the week. For the next 15 days, the GFS total precip output for CT is .2 inches.

Sunday, December 6, 2009

12-13 long shot

12-12 - WRF has some snow to start, as does GFS, but less than an inch, lasting 1-2 hrs. No other model looks like it precips until 0 at 850 line passes north, or as it passes.

12-11 - Nam has all rain. GFS puts an inch down before changing to rain -looks to form northwest of benchmark. The accum snow map is off already as we have several inches on the ground not being picked up by the gfs. NAM and GFS almost look like the northern stream sw has too much and reforms over long island, essentially moving west to east. CAN has the most front loaded before changing to rain, and does not warm aloft all that much - keeps the low over the benchmark. UKMEt backloads it - all rain. Cant tell with the euro as its interval is too great - looks backloaded, but never has us in the precip field. Call is snow, freezing rain to rain, within 2 hours. Then light rain or drizzle with high of 36.

12-9 - Euro has low moving from upper plains, northern ohio and directly over us, resulting in another WAA situation. CMC 12z run looks completely bizarre with no low or precip at all, instead temps way above normal on Tuesday - its sunday low is in florida. UKMET has a low sort of forming on sunday off the coast, but has a real low west to east across the GLakes and to our north on Tuesday. DGEX has it clocking us, but the 540 line is north of us. GFS has it going to our south with a light snow event. Literally, all over the map for 4 days away.

12-8 GFS still has coastal, but actually looks like its warming aloft even though the low is east of us. Very odd. Euro has low going to lakes?? odd. Pushes through warm front. UK met has it off shore and looks good. DGEX out to sea.

12-6 - Euro and Gfs (hr168) have this little 1016 feature off the coast for 12-13. DGEX has it going straight east off GA. Official forecast from NWS and accuweather is sunny 35.

12-7 - Euro and GFS still on this thing. DGEX goes south.

Friday, December 4, 2009

12/9 storm

12-8 - not looking good as secondary forms too close. GFS still has on its 18z run a half inch of precip falling before the 0 line goes north of here. But while temps are now below freezing, dew points are in the mid 20s which is too high for a WAA event to produce much snow. 1-3 is pushing it, unless we can get the precip in faster and heavier to start. What was front loaded is now evenly spread.

12-7 - didn't take long to get excited about this one. Its really tough though. The 18z GFS has 0 line on s shore of li at 18z with 6hr precip preceding this time at .5. 32 line at surface cuts the nw corner of CT. Accumlated snow map shows 6 inches which is down from the foot it showed at 12z

18z Nam has the 0 at 850 line south of Trenton. Sim radar has heavy snow falling with up to .5 output in preceding 6 hrs. Also shows stronger secondary storm than gfs above. Nam has temps just below 32 for danbury until 15z and the 0 at 850 until 18z. Accum snow map also shows 6-8 inches on the ground.

Again - I'll believe it when I see a temp under 25 Tuesday when I go to bed.

12-6 - all models, including ukmet blow this to our west. GFS still shows a lot of precip falling before 850 line goes north of us. Not so with NAM. Other models are hard to tell with the 12 hr increments, but they do show some support for a little snow to begin. All have quick turnover to rain. With no serious cold air in place and a 1024 high a little too far NE, this is likely a nonaccum event. Will only post on this further if snow amounts can become defined, or if serious cold (sub 25) happens tuesday night.

Not calling it snowstom yet. CAN double barrels it way to our west. Euro drives it right over us. Nogaps right over us. GFS to our north, but not to the lakes like CAN. UKMEt - has blizzard up the east coast. and this is 5 days away! Most have it starting as snow, changing to rain and possibly ending as snow. all have it way colder afterwards

Thursday, December 3, 2009

12/5-6 snow

12-4 gfs 12z snow map. Wow did this change from yesterday

UKMET from 0z 12-3 with 6+ inches

0z euro 12-3 with 2-3 inches, but mostly offshore

0z can 12-3 with mostly off shore, and dusting

WRF has 1-2 inch storm
GFS snowcover is nada - it brings it up to dc then disappears

12-4 models all shifting west. As of 12z, ukmet so far west with the 540 thickness line, that its a rain event (despite below freezing at 5000 feet). Nam also very close to all rain, even GFS is pushed back to have some rain. CAN crushes us, as does EURO. too bad they don't have precip outputs.

Wednesday, December 2, 2009

AO, NAO, PNA - should be cold

For Dec 1-15, PNA is mostly positive (ridging in west), NAO is relatively strongly negative, and the AO is very, very negative. Should result in very cold, dry weather. But the GFS only has it marginally cold with every storm cutting to the lakes. Very contradictory.