Phillyweather's Blog

The aftermath of Cyclone Nargis is being felt in the former Burma, now known as Myanmar. Nargis was the strongest cyclone to ever strike this country in recorded annals and struck the densely populated Irrawaddy Delta near the capital of Yangon. The Associated Press was reporting on Sunday that over 350 were killed from the storm and in one township in the Irrawaddy Delta over 75% of the buildings were destroyed.

CNN is reporting that many parts of Yangon were without power from the storm and that casualty totals could be higher when all reports are in.

Photo courtesy of EuroNews.

Update, 8 AM Monday: The AP is now reporting that nearly 4000 have been killed from the Cyclone in Myanmar, with another 3000 unaccounted for. This death toll is currently higher than the official death toll from Cyclone Sidr, which struck Bangladesh in November.

Source:  phillyweather.net

Photography: Grounds For Sculpture I visited the Grounds for Sculpture in Trenton on Saturday and while enjoying clouds and chilled east winds I did manage to get some photographs taken of some of the beautiful art, but more important the beautiful landscaping that is on display there. Some of the scenery there was beyond beautiful and was certainly a very relaxing and serene place.

The peacock (yes, he's real) was looking into the gift shop while I was in there, looking I guess to come inside and strut around. Take a look at the photos of the landscaping and also some of the sculpture art that they have on site.

Primary Day on the Pennsylvania side of the Delaware River has mattered little since the beginning of the modern political nomination system in the 1970's, with only the 1976 Democratic primary providing sway in the political process for a candidate. History has yet to judge where the 2008 Primary ends up in the grand scheme of primary elections of the past but the weather tomorrow will come close to matching the trend of the past elections.

Temperatures since the '76 primary have generally been in the 50's or 60's, with only the '96 Primary being excessively warm. Precipitation has been little to none, with only the 1996 primary providing even two-tenths of an inch of rain.

Statewide, dry weather is expected with increasingly sunny conditions as one travels west and north throughout the state. Temperatures should generally be in the 60's across much of the state with isolated 70 degree readings across Eastern Pennsylvania. More widespread lower 70's are likely across the I-79 corridor in Western PA.

Source:  Phillyweather.net

Since 1977, our average date for the "first 80" in Philadelphia of the year has fallen around April 15th. During this decade, we have had two March "first 80's": 2000 and 2007. This year's first 80, regardless of if it occurs on Friday (as I'm currently forecasting) or not, will be later than the running 30 year average. Thankfully for those who like warmth, it will not be as late as 1984's first 80, which occurred on May 20th.

Source:  Phillyweather.net

Case #12443 of why one can never trust computer models when forecasting weather alone. Take a look at the two maps up above of the NAM computer model, from 8 PM last night (left) and 8 AM today (right). With a stalled frontal boundary to our south and consistent guidance that indicated the front would stay south, every forecaster in town was forecasting 40's to near 50 with a drizzly off and on rain for Thursday and Friday.

Not so fast, the NAM and GFS computer models are saying. The most recent run of the GFS and the two most recent forecasts of the NAM are now bringing the stalled front NORTH as a warm front ahead of the second wave of low pressure. Both models are now tracking the low across Pennsylvania as it is a little bit stronger than prior forecast guidance had indicated. A track to the north means warm air gets pulled farther north as well. IF these most recent runs of the NAM and GFS are correct we could see temperatures near 70 tomorrow in Philadelphia and in the low 70's across Delaware and South Jersey, with 60's in the burbs cooling to the 50's in Allentown and along I-78. This warm-up would be quick as once the low moves by it will drag a cold front through the region Friday night, bringing us colder weather for the weekend.

I had talked about the waffling potential of the stalled frontal boundary earlier in the week but I did not think we would see the front move north of Philadelphia as setups like this in March do not always pan out for the warmer...typically they pan out for the colder. In most cases, temperature busts at this time of the year are not out of the ordinary and it might be wise to expect the unexpected over the next 24 hours as we could see wild, wild temperature swings.

Source:  Phillyweather.net

Considering Easter is not a set date nor a set day (ya know, like 3rd Monday of the month) holiday, the weather on Easter can vary wildly based on when the holiday falls. If you ever wanted to know when Easter is in the year, say, 2049, check out this site and you can see when Easter was going back to 1875 and going forward to 2124.

Easter's "fall date" is based on the first Sunday after the first full moon after the start of Spring. This Spring's first full moon was on Friday, which is why Easter is as early as it is this year.
Going back over the last 30 years Easter weather has varied pretty wildly. While Philadelphia has not received accumulating snow on any Easter since 1978, it has been pretty chilly (1996's high of 41 was the coldest of the last 30 years, on April 7th) on a few occasions but we have seen a 41 degree swing in high temperatures from the coldest since 1978 and the warmest (82, 1986, on March 30th).

We have had only one "frosty" Easter morning going back to 1978, last year's 31 degree low (April 8th). Our 2008 Easter weather will be similar but slightly warmer than 2007's, with a high temperature in the upper 40's expected in Philadelphia.

Source:  Phillyweather.net

The Storm of the 20th Century was firing up on March 12th, 1993, as a potent storm system in the Gulf of Mexico, which computer models were forecasting to impact the East Coast as a significant snow and wind storm the next day. The Superstorm of 1993 brought significant snows and significant damage to much of the East Coast, with a total financial impact of between six and ten billion dollars, killing about 300 individuals in one of the deadliest winter storms in recent times.

In Philadelphia, the Superstorm brought a mixed bag of heavy snow, sleet, and some light rain for a time as the low pressure system tracked just east of Interstate 95 through the Mid Atlantic. You can check out all the observations from the storm, as well as some cool graphics from the Superstorm at Ray Martin's New Jersey Storm Archive. Martin is a meteorologist with the National Weather Service in Elko, NV, and has archived many great images from the Superstorm.

The Superstorm tracked from a landfall point near Apalachicola, FL, around 1 AM Saturday morning to a position near Salisbury, MD, around 7 PM Saturday night. The storm deepened to a remarkable pressure of 960 mb, equivalent of low end Category 3 hurricane.


Surface Map Graphics From Northeast Snowstorms CD-ROM

On satellite, the presentation was one of a classic storm system that wound up quickly and powerfully. You can see the extent of the storm's cold front into the Caribbean Sea, covering 35 degrees of latitude by the night of the 13th.


A search of YouTube will bring you a wide plethora of snowfall video, radar loops, and streaming video from The Weather Channel. Pittsburghers may remember this coverage of the storm as well.

As far as Philadelphia and vicinity was concerned, snowfall totals ranged from only a few inches along the coastline to as much as twenty inches in Harrisburg, with isolated amounts in the Poconos of up to three feet. Among the regional totals, Allentown received 18", Quakertown 17", and Millville received 13" of snowfall.

This week is Pennsylvania Weather Emergency Preparedness Week. Between March 10th and 14th, the National Weather Service is spending a day focusing on a different aspect of weather disasters that can impact you directly.

Schedule of Events MondayMar 10TornadoesRead more... TuesdayMar 11Severe ThunderstormsRead more... WednesdayMar 12Flash FloodsRead more... ThursdayMar 13River FloodsRead more... FridayMar 14Skywarn SpottersRead more...

In 2006, Pennsylvania was struck by eight tornadoes, including five reported tornadoes on December 1st in the latest tornado outbreak in the state's recorded history. Other significant tornado events in the state's past include May 31st, 1985, the Limerick tornado in 1994, and the Lyons tornado in 1998.

As we know all too well, flooding is a major problem in Pennsylvania as we have seen several flooding events over the past few years, from the Delaware River flooding in 2004, 2005, and 2006 to the flooding of the Schuylkill basin in 1972 and 2006.

The National Weather Service has preparedness guides available on a number of weather-related subjects to help you know what to look for and how to protect yourself as best as possible in case of weather emergencies.

Credit:  http://philadelphiaweather.blogspot.com/2008/03/pennsy
lvania-weather-emergency.html

Yesterday's wild weather was punctuated by three events of varying dramatics. First, the heavy rainfall that moved through Philadelphia between 10:30 and 2, bringing a good inch of rain to the region and helping bring a total storm rainfall of two plus inches to much of the I-95 corridor.

The second was two squall lines that developed and moved through the region during the afternoon. The first moved through between 3 and 5 and brought some heavy showers and some gusty winds to the region. The second squall line, in association with the actual cold front, crossed the region between 5:30 and 6:30 and that front meant business.

Winds gusted to 71 mph in Northeast Philadelphia with the storm, causing damage to homes throughout the area and knocking out power to tens of thousands of residents. Phillyweather.net reader Reilly Sharp commented that nickel-sized hail fell in Newtown, Bucks County from the storm system and that the sky looked green. Reilly added that "intimidating green lighting and quickly whipping winds occurred" with the storm as it passed through Bucks.

The storm came through my area around 5:30, with low hanging clouds eerily similar to the War Of The Worlds scene when the lightning was striking the same spot repeatedly, right before those fancy looking machines the aliens were driving came out of the ground. If $200 million big budget special effects movies have taught me anything, it's to find comparisons in weather conditions to movies with god-awful endings. The storm brought little in the way of rain in this area but winds did gust in the 40 to 50 mph range across Upper Montco as the squall blew through.

The third facet of this weird, wild, and wacky storm was the temperature swings. Temperatures dropped from the 60's in the mid afternoon in Philadelphia to the 30's, with a biting west wind, at midnight. Allentown dropped 22 degrees in three hours and temperatures across the region crashed with the passage of the cold front.

After a windy and cold day today in Philadelphia we should see the weather improve as we move towards mid-week, with (yep) another storm looming for next weekend with (yep) more rain in the offing for our region.

Credit:  http://philadelphiaweather.blogspot.com/2008/03/mother-
natures-mood-swings-on-display.html

I talked about three months ago about the "myth" of snow droughts in the Delaware Valley. Given our relatively low average winter snowfall (21.6" over 123 winters, not including this winter), there will be periods of time where Philadelphia will see years with less bountiful quantities of snow.

While the past two years have been low on snow amounts, thanks to sleet last winter and thanks to La Nina this winter, the truth is through last winter we averaged more days with at least 0.1" of snow this decade than the 1990's and have had more 6" snow events this decade than any decade since the 1960's. Unfortunately (if you like snow), for all of the snow days we have been seeing amounts have been on the nuisance side for the most part, especially in the last couple of years. All those 0.1" and 0.2" clipper events from the past two years have added up!

In the last 15 years, Philadelphia has seen two of its ten snowiest winters (95-96 and 02-03), with seven of the last 15 years (not including this winter) featuring snowfall that is above the current 30 year "average" of 20.2". We have seen a bit of a feast/famine cycle regarding snowfall around here as six of the past 15 years have featured less than 75% of normal snowfall, including four years in five during the mid and late 1990's. As you can see in the snowfall chart I posted below snowfall in recent years has been very feast or famine.

While we have been feasting at the trough of snow then starving the following year, it could be worse. Between 1925 and 1932 Philadelphia had six years in eight where they did not receive 15" of snow, with only 1926 (19.1") and 1928 (15.5") besting 15" even though both years featured below normal snowfall. Another snow drought in Philadelphia occurred in the 1950's, with five years in the decade featuring less than 75% of our current snowfall average, with only three years above average.

While it is possible that we could be entering another lull in bountiful quantities of snowfall, the truth is until we see flakes falling from the sky guessing snowfall amounts months in advance is an inexact science. Forecasts this winter ranged from 11.6" to as much as 23" (unfortunately, my forecast) of snow and as of today only 6.3" of snow has fallen in Philadelphia. Last winter's forecasts were quite aggressive for snow given it was an El Nino winter, yet only 13" of snow fell last winter. Given the recent feast-famine cycle in snowfall in Philadelphia, it could just be a matter of time before the next bountiful snowfall winter hits us over the head. However, when that hits, don't expect a repeat performance as back-to-back 30" snowfall winters have only occurred only once in Philadelphia in the last 90 winters, and back-to-back 25" snowfall winters have occurred only seven times since 1918 and just twice since the 1960's.

Source:  http://philadelphiaweather.blogspot.com/2008/03/more-o
n-snowfall-droughts.html

Those of you who have been regular readers of my site know I like to talk about wild and crazy climate. Today's climate corner focuses on record temperature spreads.

March has some pretty extreme weather (except the days Philly is stuck in the 30's with an east wind and marine layer overcast) as it is a major indicator that we are about to exit one season and enter into another. The month has shown itself to feature some of the wildest temperature swings of any month and it has the second largest potential temperature swing from record monthly high to record monthly low of any month, topped only by April (thanks to an April Fools Day record low of 14 degrees). On a day to day basis, however, March provides the wildest varieties of weather on a single day going back to 1874. March 21st featured a record high of 85 degrees and a record low of just 6, a spread of 79 degrees.

There have been 33 days in Philadelphia where the record high and record low have a 70 degree or larger swing. That means that when you watch the news and you see the almanac and they show the record high and low, the difference between the two would be 70 degrees or greater.  Of those, February provides the most "extreme" record spreads, with 10 days. March and January are both tied with 9 days with a spread of 70 degrees or more. April has three days with such a spread and December has two.

Why does this happen most frequently in January, February, and March? The combination of strong cold outbreaks as well as warmer air riding up the East Coast make such extremes in temperature possible. While the record highs in January and February are lower than those of March and April, the record lows are typically also lower.

March 1st is the first day where the record high in Philadelphia stays above 70 degrees consistently, a streak that lasts until December 1st. While record lows can still dip down into the single digits as late as March 21st, our earliest date where record highs are above 80 degrees is coming up on March 20th. A chart showing the record temperature spread between highs and lows is below...as you can see the gulf between the two is quite wide in the winter but narrows considerably in the summer.

Check out the list of the 33 records I brought up and a graph to show record highs and low throughout the year

Tomorrow is the once-every-four year Leap Day, that day that gets to balance out the calendar so everything is in relative balance (sorta) with the whole time and space continuum (or something like that). Going back to 1876, the history of Leap Day in Philadelphia does not have much of a history to it in terms of extraordinary weather.

The warmest Leap Day was in 1972, with a high of 69 degrees. The most rain fell in 1896, with 1.03" of precipitation on a 57 degree day. Temperatures have generally been in the 40's, with an average Leap Day temperature high of 44.3 and an average Leap Day low of 28.75. The forecast Leap Day 2008 will be below those averages by several degrees.

The snow history going back to 1884 has been laughable, with only three Leap Day accumulating snowfalls (1920, 1960, 1968) over 32 Leap Days, with a "record" snowfall of one inch occurring in 1968. With the potential of snowfall in the forecast for tomorrow, it is possible we see our 4th accumulating snowfall on Leap Day. Not exactly a historic event but it is a rare event nonetheless.

For Leap Year Graphics, check out: http://philadelphiaweather.blogspot.com/2008/02/leap-d
ay-weather-history.html

http://philadelphiaweather.blogspot.com/2008/01/first-c
all-for-sunday-night-event.html

Philly should get about an inch of snow from this storm, more to the north and east. Full discussion and map forecast available at my website.

A tricky forecast and a tricky drive forthcoming for some in the Delaware Valley as a mixture of snow, sleet, freezing rain, and rain will be moving in from the west starting early Sunday morning. If you haven't already, check out the discussion from last night discussing the synoptic setup and where the lows are tracking.

There will be two main waves of precipitation with a lull in between the two. The first, caused by overrunning moisture on top of a warm frontal boundary, will lead to a period of wintry precipitation for the Delaware Valley starting early Sunday and continuing through at least midday. Precipitation should start in the form of snow and then mix with sleet. In Philadelphia, a changeover to rain should occur early in the afternoon hours as warmer air aloft mixes down to the surface.

Here is my first call for accumulations for Sunday and Sunday night in the Delaware Valley.  These are subject to change and may based on data as we close in on the event.

'Tis the season for me to break out the snowfall chart! What is the snowfall chart? Well, the snowfall chart is an excel spreadsheet that I developed last winter and used here to show trends in snowfall that the major computer models are projecting. As you may or may not know, the GFS and NAM are the two main short-term computer models that are used in meteorology to get an idea of what might happen. There are four computer forecasts issued each day by each computer model. CoolWx.com, a neat website, has these computer forecasts broken down by precipitation type in a neat chart format, one that can be changed to suit most major locations in the United States.

Since there is a plethora of data and a plethora of locations to analyze, I have taken the data from that website and convert it into a spreadsheet that I use to track for significant changes over the course of a possible snow threat. Last winter, this spreadsheet was developed to get a sense of potential snowfall amounts whenever there was a threat for snow in the region within four days and to give readers here a sense of where a storm may trend...will it be colder, snowier, warmer, rainier?

Check out the first snowfall chart of the season for Sunday's system.  I'll try to update these daily so you can see what the models are thinking regarding the upcoming storm.