Saturday, March 31, 2007

17 comments:
YOU'VE GOT TO BE KIDDING...
EASTER COLDER THAN CHRISTMAS ?!?


While I can't claim ownership to that headline (Joe Bastardi of Accuweather alluded to it first) the indicators are clearly there and shown on the GFS projection for early Sunday morning, April 8. As I mentioned in my blurb last week... frost on the bunny ears is looking more likely. In Baltimore, the daily high temperature recorded at BWI for December 25, 2006 was 50 F, and the 24-hour low 30 F. In Philadelphia, the same numbers were 49 F and 33 F respectively. If the upper level 540 thickness line (dashed blue line below) does get to the Virginia/NC border as shown, I would expect the map above to verify fairly closely. That means Easter morning the Mid-Atlantic may be looking at widespread 20's and just breaking into the mid 40's by afternoon. But wait! It gets worse. (I know, I wish this was an April Fool's joke, but it really is not.)
gfs_slp_192s
You should know both the GFS and Euro have begun to advertise a fairly intense (and unwelcome) cold snap to enter the Great Lakes, Mid-Atlantic and Northeast by late in the week, starting as early as this coming Thursday. This may be followed by a series of Low pressure systems forming along the southern boundary of that cold air. The map below is a 10 day hint of snow possibility on or about Tuesday, April 10, but it is just a very early projection.

As with all storms, this one will need "the right amount of cold and moisture at the right times." Yes, I know you're thinking "how could this be, a snowstorm in APRIL? Come on." Well, April 6 in 1982 and 2003 produced memorable snows in east central PA and New Jersey. In fact as late as April 23, 1986 there was an an inch of snow that morning at my home in suburban Philadelphia, and northern New Jersey/southern New York received 2 feet of heavy wet snow from the same storm. I remember this well because exactly one year earlier on the same date in 1985, Philadelphia recorded a record high of 94 F along with many other cities in the Northeast.

So despite the strength of the April sun, there can still be snow this time of the year and this will no doubt dishearten the spring-a-lings like me who are ready to start planting and are so totally done with the snow this year. In fact I even reverse-jinxed the storm because I told my wife, "Look dear, I'm putting away the shovel and salt (for the second time)...that means it'll snow one more time." Thus the Adventure of Winter 06-07 continues yet again, so stay tuned and this coming Friday we'll revisit the potential of a final? snowstorm once my quarterly grade scans are done and in on time.

Tuesday, March 20, 2007

18 comments:
WINTER RETURNS, JUST IN TIME FOR SPRING
images courtesy of Accuweather.com

Equinox Week 2007

An early week update to say that Monday night's clipper through the Great Lakes and Northeast brought with it a temporary chill which will make the first full day of Spring (Wednesday) feel downright January-ish. Highs in my area of Maryland are only expected to reach the mid 40's with lows once again in the mid 20's. But fear not Spring-a-lings (a term of endearment for members of the discussion community who favor Spring)...your long awaited warm-up will return for a brief time late this week and into next week. As we head towards the end of March and Palm Sunday Weekend, there might be some April Fool's mischief lurking in the time frame from the 30th to the 3rd, and it's no joke that this inappropriate meteorological behavior could include SNOW for portions of the Mid-Atlantic and Northeast. More on that mayhem later, for now we can finally celebrate the arrival of "Astronomical" Spring at 8:07 PM EDT today.

Sunday, March 18, 2007

27 comments:
MARCH 16-17 STORM GRADE REPORT

Final Snow/Sleet Totals across the Northeast, as reported to PSU's Public and Spotter Page.

March 16-17 Snowfall Map

This storm report is based on a procedure we've established on the site since since 2005. The actual amount is graded by it's % deviation from the forecast, and then grades on a GPA scale. Now in fairness...we have not yet reached consensus on the discussion board here if the grade should be actual accumulation of just SNOW or can it be SNOW & SLEET or just SLEET. Obviously the 2 recent storms have retrained everyone as to what sleet is and can do to a forecast.

Also in fairness…please note I don’t just pick and choose among the best actual observations. Frequent long term readers know and can vouch for the fact that when I say “NYC / Boston / PHL ” I have used the same locations each storm… NYC = Central Park / Boston = Logan airport / PHL = airport. The other locations are from members of the discussion community based on their obs posted in the comments.

Just for a new reader to know there’s no sugar coating here. The numbers speak for themselves, good, bad or ugly.

The numbers are: Final GPA / City forecasted / amount forecasted / actual / %dev / grade

The GPA is determined by the standard 4.0 academic scale:
4.0 A / 3.67 A- / 3.33 B+ / 3.0 B / 2.67 B- / 2.33 C+ / 2.0 C / 1.0 D / 0.0 E

0.00 / Baltimore (BWI): 2.0 / .6?/ 70%/ 30% = E

3.33 / Dundalk, MD: .75 / .85 / 12% / 88%=B+

0.00 / Philly (PHL): 6.0 / 3.0 /50% / 50%=E

2.33 / New York (Central Park): 7.0 / 5.5 / 21% / 79%=C+

4.00 / Boston (Logan): 8.0 / 8.1 / 2% / 98%=A

0.00 / Greencastle, PA: 9.0 / 5.0 / 45% / 55%=E

2.00 / Martinsburg, WV: 10.0 / 7.0 / 30% / 70%=C

2.00 / Paoli, PA: 7.0 / 5.0 / 29% / 71% = C

0.00 / Bucks Co, PA (Doylestown, PA) : 11.0 / 5.7 / 49% / 51%=E

1.00 / Central NJ (New Brunswick): 6.0 / 4.0 / 34% / 66% = D

0.00 / Fallston, MD: 4.0 / 1.0? / 75% / 25%=miserable E--- sorry Terpguy

So despite your claims that “this guy is always right!” you can plainly see that is not true!

Storm Forecast GPA = Less than thrilling 1.33 / (some would say, it’s at least passing! But far less than the C average of the February 11-12, 2006 Storm or the January 2005 Blizzard.

WHITE FOR ST. PATRICK'S DAY,
THEN BACK TO GREEN, then white again?

So your 2 week forecast should have been something like this:

THIS WEEK: 80's then much colder with rain changing to snow and sleet.
Keep scrolling to see the forecast for next week and beyond.

St Patricks Day Morning 2007

Ice-encrusted backyard of "Fort Jackson" as we call it (named after our street)

Mid Atlantic Surface Temps Sat 3-17-07

Seems like I've posted this same map before, a couple times this winter.


NEXT WEEK: Chilly and a bit cloudy until mid-week, then sunny and becoming warmer by late in the workweek. Mid 70's by Saturday from southern PA south to Richmond, near 70 Philly to NYC, 60's from NYC north to Boston.

( I knocked out my claim to 90 because the clipper coming across Great Lakes Sun-Mon will reintroduce second High I theorized early last week, holding mid-week temps down a bit)

A Spring Fling

WEEK AFTER: Turning colder with snow possible by Palm Sunday Weekend?!?!?

Palm Sunday Weekend 2007

What part of this forecast is an early April Fool's Joke? Well, the snow part I hope. I found those maps on a weather discussion board called Eastern US WX, so I am not claiming to have discovered the info on my own. But I thought the extremes were so interesting you just had to see them. I can see how we COULD warm up into the 70's, if the Polar Vortex near Alaska goes to town strengthening onshore Pacific flow into the West while the Atlantic Ridge becomes the major influencing player for much of the Eastern U.S. Concurrently, if the North Atlantic Oscillation and Arctic Oscillation remain strongly positive the next 7-10 days, this would also allow warm air to surge across most of the country. These climatic features are a measure of how much the Icelandic Low and Atlantic Azores High "oscillate" back and forth across their portion of the Northern Hemisphere over a period of time. If the NAO goes positive, it means the Labrador-Icelandic Low would be retreating north, holding the Polar Jet in central/northern Canada. Thus the Azores-Bermuda High can take over and influence weather more along the East Coast.

As for the theorized Palm Sunday Weekend storm...well, sometimes long range (7 day+) model projections are to be taken with less than a grain of salt. In fact, you can't even use salt this time because Home Depot ran out weeks ago. I tell you about this storm purely for entertainment purposes only, because the GFS has shown on just one model run this morning, from Hour 324 to 372 (weekend of 30th) a possible snowstorm for the Mid-Atlantic and Northeast. The only shred of "future evidence" that could back up this outlandish claim is the NAO/OA are both forecasted to strongly tank negative by the 30th. Sometimes 14 day projection on the Climate Indices/Teleconnectors never pan out or even trend in the opposite direction, other times they are verify fairly well. So were the NAO/OA to go 2 deviations below normal like that, it is would indicate cold air might again invade the Northeast U.S. just in time to disrupt plans for Palm Sunday Weekend. This all sounds like a skipping CD I can't clean off, and I'm not buying that scenario anyway (that's analogous to a broken record for our more seasoned readers) so I'll stop there and revisit in 7 days.