Ph.D. Student - Earth System Science (UC Irvine), B.Sc. - Atmospheric Sciences (Cornell University)
By: Zachary Labe , 10:58 PM GMT on November 20, 2010
"Afternoon Thoughts" (Updated 11/20)
"Stopping by Woods on a Snowy Evening"
Whose woods these are I think I know.
His house is in the village, though;
He will not see me stopping here
To watch his woods fill up with snow.
My little horse must think it queer 5
To stop without a farmhouse near
Between the woods and frozen lake
The darkest evening of the year.
He gives his harness bells a shake
To ask if there is some mistake. 10
The only other sounds the sweep
Of easy wind and downy flake.
The woods are lovely, dark, and deep,
But I have promises to keep,
And miles to go before I sleep, 15
And miles to go before I sleep.
Robert Frost remains one of my favorite poets to read for the exactly simplicity of the poem. Above the speaker is in fact walking through woods draped in a fresh cover of snow that remains falling. And the speaker asks what is a fare representation of the woods. Do they represent inner human darkness or a chance of opportunity into the unknown? We have all likely be in an instance late in the evening, either driving or walking, through a heavily wooded region. And while the nearest of human civilization seems like a world away, the woods act as a boundary. While they seem dark and evil, they represent an opportunity to take a chance. "The woods are lovely, dark, and deep." Society would typically not authorize a walk through the woods late at night due to fear of human evil (danger), but they represent a mystery that wants to be explored. And as the speaker is looking into the dark woods, the mystery speaks grace of a new opportunity, a new chance, a new beginning. And the final stanza of the poem shows the speaker is at bliss, "And miles to go before I sleep."
The poem is a fantastic metaphor for many challenges faced in life. Society condemns the unknown challenge for fear of darkness. What is unknown to many, is automatically bad. But new, offers the chance for an opportunity. Nature is the only true untouched frontier from human evil. Many of Frost's poems have been corresponded with choral music. For those who have been reading my blog, I am a member of one of the top five high school choirs nationwide. Choral music is an art form just like any other music. Here is a fantastic version of the poem by Eric Whitacre...
Unfortunately copywrite laws from the Frost foundation caused Eric Whitacre to change the lyrics to the popular poem "Sleep" and this is one of the only recordings left of the original lyrics.
"Current Surface Plot"
(Courtesy of HPC)
(Courtesy of Wunderground)
(Courtesy of NOAA)
"Forecast Discussion"(Pennsylvania, Maryland, Delaware)(Updated 11/20)
A strong 1032mb high pressure will begin to depart the Northeast on Sunday after the weak cold front passage Saturday night. H85 thermals are not terribly cold for Sunday, but with a high pressure in Quebec, the flow will be out of the north. Surface high temperatures will be cold regionwide and around 5-7F below normal. Mid 40s are likely for much of the region below 1000ft, with highs in the lower 40s for the higher elevations. Towards Maryland and Delaware highs will adjust into the upper 40s and possibly lower 50s along the Chesapeake and Delaware Bay. Sunshine will be regionwide on Sunday with only a few stratocumulus over western Pennsylvania. By Sunday night the flow will shift out of the east with a strong maritime influence. GFS/NAM prognostics indicate even some light 0.01-0.03in QPF over parts of eastern Pennsylvania as there is the potential for a bit of drizzle under low stratus that will form overnight. BUFKIT fog hodographs for KMDT indicate no change in vertical humidity, probably indicating some low ceilings to form over eastern Pennsylvania Sunday night below 500ft accompanied by drizzle. Some areas may receive fog from the marine layer, but I think it will generally be stratus dominated. Lows will be in the low 40s for eastern areas with lower 30s over western areas as they will be under clear to only partly cloudy skies. A 1004mb low pressure will circulate up through the Northern Plains causing quite a snow storm over the Western United States. By Monday this will drag a weakening cold front towards the western portions of the Northeast. This cold front will be moisture starved with only less than a tenth of an inch of QPF over extreme northwestern Pennsylvania. Although the low stratus and drizzle may linger into midday Monday for eastern areas. Highs on Monday will be well above normal and up to near 60F for areas in southern Delaware/Maryland. Elsewhere highs in the 50s are likely. Another 1000mb low will track up the Great Lakes with a bit stronger of a cold front advancing towards the region by Tuesday night. Light rain is possible into western Pennsylvania by Tuesday late morning. H85 thermals will increase to +10C by Tuesday night/early Wednesday as the southwest flow increases ahead of the cold front. The storm system will be moisture starved so QPF with the frontal passage on Wednesday will be around .25-.50in favoring western areas. Areas in the east may be hard pressed to see .1in.
The air mass behind this cold front is not much cooler as the flow quickly shifts to the southwest ahead of yet another 1000mb low moving up through the UP of Michigan. With no high pressure to the north, little cold air damming will occur with the overunning precipitation on Thursday, although high temperatures may be a tad on the cool side. The GFS and ECMWF differ on their representation of this third system with the recent operational GFS keeping the heavier 0.5in+ QPF to the south of the Mason-Dixon line with the H85 0C line right around the NY/PA border. I will have more on this storm system throughout the week, although I think it will be predominately rain for all areas. Also I do not think the cold air catches up with the precipitation, so it will probably not be a rain changing to snow situation. Finally the much advertised cold air mass enters the region on Friday with H85s falling below -5C as the flow turns anticyclonic with lake effect snow showers. Total weekly QPF for western areas in the northern Middle Atlantic will likely be around 1.0in with eastern areas less than 0.25in. Southern areas may do well though with the overrunning Thanksgiving rain with weekly rain totals for those areas around 0.50in. Highs will be above normal by 5F or so much of the week after Sunday through about Wednesday. Lows will also be mild under cloud cover much of the week as the weather will be unsettled.
(Courtesy of Penn State Meteo.)
"Current Water Vapor Loop"
(Courtesy of Penn State Meteo.)
"Lake Effect Snow Conditions" (Updated 11/20)
The lake effect snow machine will begin to get cranking by the end of this upcoming week as a sharp anticyclonic northwest flow dominates the Northeast. Looking at BUFKIT GFS profiles, the wind vectors appear to be 20-30 knots out of around 320-325 degrees on Friday shifting to a more relaxed 290-300 degree flow as drier air mixes into the region. The 980mb low will continue to deepen near Newfoundland after tracking the Great Lakes earlier in the week. The cold front will push through early Friday accompanied by a weak shortwave enhancing orographic and lake effect snow showers. Directional shear will limit organization of lake effect snow bands and the north-northwest flow will keep snow showers mainly across northern Pennsylvania up through much of western New York State. -20 Omega growth is currently advertised by GFS BUFKIT for KERI near the surface. Moisture will be readily available aloft for the short period of early Friday through Friday evening. Orographic lift will help aid in snow showers over western Pennsylvania into the Laurel Highlands. H85 thermals will drop to near -10C with 1000-500mb thicknesses nearing sub 530dm for much of the Northeast. Overall not really expecting too much lake effect snow accumulation due to short lived available 700mb moisture and directional shear aloft. But many locations from western Maryland up through western and northern Pennsylvania may see a coating up to one inch. Current GFS QPF prognostics show a decent snow shower coverage early Friday afternoon over the region. Even a few flurries, light snow showers may move just downwind of the Appalachians. 2m boundary layer temperatures will be at or below freezing for most all of the lake effect snow belt regions with other locations at 40F or below. A few patchy 1-3in snow amounts are possible over the Laurel Highlands in Cambria and Somerset Counties and also up across McKean, Crawford, Mercer, Erie, and Warren Counties. A patchy C-1in is possible also in northeastern Pennsylvania in Wayne County and down into the Poconos in Carbon County. Model guidance suggests the 320 degree flow may favor a lake effect streamer off of Ontario down through Binghamton and northeastern Pennsylvania towards Saturday as the shear relaxes a bit, but dry air moves in. Usually this allows for the snow shower activity to progress from cellular to linear before relaxing. This lake effect snow event will not favor snows into Buffalo or Cleveland, but more for the western New York plateau down through northern Pennsylvania. Finally of one last note, the 11/20/2010 18z GFS shows an interesting snow event for northern New England as a shortwave progresses just north of New Hampshire and Vermont. QPF prognostics over well over .5in of upslope precipitation allowing for a possible large upslope/orographic snow event for those typical areas in northern upstate New York, northern Vermont, and northern New Hampshire. This period would be around Saturday (just something to keep an eye on for those areas).
"Current Great Lakes Water Temperatures"
(Courtesy of NOAA)
"Long Term Outlook" (Updated 11/20)'
A quick look a global teleconnections shows an obvious picture a colder than normal air mass over the eastern United States. The NAO, which has hovered neutral to negative since the first week of October, will take a sharp dive to near -3. The PNA, currently at -2, will rise back to near neutral encouraging a bit of ridging over the western United States. The stark negative EPO will signal the transition of a cold air mass currently over northern Canada to come sweeping down into the contiguous United States. The cold air mass is evident by the near -5 AO. While the teleconnections are simply indicators of averages for positions of troughs and ridges, they do not tell the entire story. The position of the Polar Vortex is critical near Alaska. The current Great Lakes cutter this week will be the new acting PV by the end of the week as it moves upstream. Its position is still up in the air, but will likely be over central northern Canada. When the PV is located over Alaska (typical in La Ninas) then often very warm air floods areas east of the Mississippi River with the cold displaced to the west. Operational forecast models are quite different in the long range, with the ECMWF featured a transient cool air mass quickly retreating by the 29th or 30th of November. The GFS on the other hands installs the cold prolonging well into early December. It is not a matter of which model is correct.
While forecast computer models play a critical role in long term forecasting, they are not always accurate. Looking at the players on the field with a neutral PNA and starkly west-based negative NAO combining with a negative PDO and weak solar regime, I think the pattern will lead itself to be volatile. I think we will see a period of well below normal temperatures as a -2SD trough enters the region right after Thanksgiving. I would forecast highs at being a fare 10-15F below normal accompanied under sharp cyclonic flow. This will last for a few days into the end of November. By the 30th or so, the core of cold air (sub 525dm 1000-500mb thicknesses) will be exiting. Towards the first week of December cooler air will linger with means zero to a few degrees below normal for high temperatures. This will last through at least the 8th or so of December, possibly a bit longer before the negative NAO retreats and the MJO begins to pulse into phases 3/4. None the less, this is not an arctic intrusion and talk of the coldest November Outbreak in just under a decade will not verify. This is some seasonal cold air that is often typical around Thanksgiving. What remains a bit more important for winter-lovers is the active Pacific. We are being dominated by a positive AMO and tight wavelengths in the Pacific advising a potentially stormy period as we arrive in early December. Analogs produce a few rain/snow storm chances during the first week of the month. I had been calling for the first accumulating snow for inland locations north of Baltimore within the first ten days after Thanksgiving and that still remains on the table. The operational 12z GFS still shows a few storm chances into the beginning of December. Active wavelength periods are Dec 2-3 and/or 5-6 so keep them in the back of your mind. Snow is not too far away. There is the potential for this pattern to go quite sour in its initial forecast. While I do not think there is any likelihood of this verifying colder than what I am predicting, there is the potential for several days of above normal temperatures if storms track to our west. The operational ECMWF shows a 240hr event with a inland runner/miller B redeveloper. Still though, this floods the east with warmer air before it redevelops. If we do not get the 50/50 low in a favorable location, then I think this pattern will take a more Nina approach. Overall this period after Thanksgiving cold weather will underperform compared to early forecasts.
"Current NAO and PNA Predictions"
(Courtesy of NOAA)
"Anchorage, Alaska Tower Cam"
*Back due to popular demand!
"Monthly Temperature/Precipitation Outlook"(November)(Updated 10/23)
I think I am going to trend a bit on the mild side for the upcoming November despite interesting teleconnections. Mean 500mb guidance from the past week show a bit a southeast ridge beginning to flex its muscle into the southern Middle Atlantic. Latest 10/23/10 0utc GFS 10-14day 500mb mean actually supports this continuing in that range with a 588dm ridge over the southeast. Right now the polar vortex is just north of Alaska by about 200mi, which is good for now. But guidance suggests this may sink southward towards November. This tends to favor ridging over the east coast and troughing over the western United States up through Alaska and the Canadian Rockies. But current ensemble runs indicate a negative NAO to open up November. There will likely be an eastern cool pattern during the first week of November. The La Nina continues to show that it is already one of the strongest La Ninas on record. But it is encouraging to see little temperature drops in Nina 3.4 SSTs. For those looking for an early season snowstorm this year, a few encouraging signs can be found in the cryosphere. Levels are at around normal values, which are actually higher than the previous few years. Siberian snow cover has shown impressive gains in the last two weeks and has reached above normal levels. Also North America snow levels have increased in northern Canada and Alaska courtesy of the trough moving through and associated low presssure system. None the less, I believe typical La Nina conditions will dominate November's weather with a southeast ridge. But cooler weather may return towards the end of the month with perhaps the first inland snowfall in this time period around or just after Thanksgiving. We shall see how those wavelengths turn out. Precipitation chances are right around normal for all areas. The farther south one goes in the Middle Atlantic will dictate how anomalous the warmth is this month as weak troughing from the negative NAO may be enough to save some areas in Pennsylvania from the warmth.
"Temperature and Precipitation Outlooks from Climate Prediction Center for next 30 days"
(Courtesy of NOAA)
-Winter Outlook 2010-2011...Link.
"Here northeast of Harrisburg 2010-2011 winter statistics"
Current Snow Cover- 0in
Monthly Total (November)- Trace
Seasonal Total- Trace
Winter Weather Advisories- 0
Winter Storm Warnings- 0
Ice Storm Warnings- 0
Blizzard Warnings- 0
Freezing Rain Advisories- 0
Winter Storm Watches- 0
Lowest High Temperature- 38.7F
Lowest Low Temperature- 20.8F
Wind Chill Advisories- 0
Wind Chill Warnings- 0
(Snow Storms Stats)
The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.
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