Sunday, October 31, 2004

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80 DEGREES AMONG THE PUMPKINS OF MY BACKYARD IN DUNDALK THIS AFTERNOON. That is a wonderfully good sign for all you powderhounds out there. Don't get spooked by the nice weather, because it means winter will creep up on us ever so slowly. And then one fine morning in early December, you will open your window to a frightfully white sight of snow, snow, snow.

It means that the pattern will get throw out of whack for November, leading to a Thanksgiving repeat of the Halloween warmth, which in turn produces below normal temperatures for early December. Throw in some Gulf and Pacific moisture courtesy of our weak El Nino, and presto! Instant snow day the first week of December.

So enjoy the sunshine and blue skies, it's a sign that good days are ahead, that is if you like snow.

Monday, October 18, 2004

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With the tropics quiet for a moment, it is time to release the official Foot's Forecast for Winter 2004-05. (Drum roll please....)

The map below is the basis of this forecast. What you are looking at is the departure from normal sea surface temperatures (SST) across the world. This is available on a daily basis from the link to the left, and it is one of the best indicators of what is to come for the winter, based on past trends. This map is produced by the U.S. Navy.

While it might seem to a casual observer a bit of a stretch to base an entire winter forecast on the ocean water temperature map of one particular day, let me give you some reasons why it is possible:

1. It takes a long time for the ocean to change temperature patterns, thus SST signals are like the performance of the stock market. Both are strong indicators of what is likely to happen down the road 4 to 6 months from now. I am confident with this forecast because the SST signals this October are much warmer than they were in October 2002, which led to the record-breaking snowy winter of 02-03, culminating with the February 2003 Blizzard on the East Coast.

2. Historical trends show that when the United States observed a cooler than normal summer with above normal hurricane activity, the result was the East Coast recorded a cooler than normal winter with above normal snowfall. The other strong predictor was the state of SST's off the West Mexican Coast and into the central Pacfic in mid-October. In more than 30 years of record-keeping, those signals led to a snowier winter for the East coast.

(Snow days refers to a snowfall of 5" or greater that closes Baltimore Metro region schools.)

Overall predictions: 6 snow days, accumulation total at BWI airport: 35" for the season.
60% or greater likelihood of a major snowfall exceeding 12" at least once during the season
80% or greater likelihood of a medium snowfall exceeding 6" at least twice during the season.

Rest of October: Overall normal to above normal temperatures

November: Cold to start, then warmer toward the end.
First hint of snow or flurries around the 15th.

December: Very cold early, then a stretch of mild weather from mid-month until early Jan.
Snow days: 1 within the first 10 days of the month.

January: Mild early, then a snapback to cold from mid-month to the end.
Snow days: 2 during the second half of the month.

February: Cold to start, then mild in the middle, then cold towards the end.
Snow days: 1 early in the month, 2 late in the month

March: The last occurence of accumulating snowfall no later than the 10th.

So now the fun begins as we get to tick off the days as winter approaches, and see how close the forecast will verify. I'm sure more than a few of you will keep me honest in this process.

Wednesday, October 13, 2004

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Coming almost 50 years to the day of Hazel's arrival on Oct 17, 1954 will be two impressive semi-tropical systems riding first over the Mid-Atlantic and then up the Eastern seaboard for most of the weekend, starting Wednesday evening. Those teachers planning to attend the State Teacher's Convention in Ocean City will find themselves in an ocean of rain. Everyone else will have to postpone that hayride or pumpkin patch trip.

The purples and blues indicate 1/2 to 1 inch of rain just for the 6 hour time period of this map from Friday night to Saturday morning.

The Mid-Atlantic is also going to get hammered Wednesday night into Thursday night by the development of thunderstorm lines downwind from the main storm out in the Ohio Valley. This system is the remnants of Matthew, which like many downgraded tropical depressions this year, has held together surprisingly well and continues to drench the Missouri-Indiana area with heavy rain.

A line of strong thunderstorms is developing in the Shenandoah Valley, and should roll towards the I-95 corridor by this evening, moving southwest to northeast. The interaction of the very moist air and very dry air will create some terrific storms, which will seemingly pop out of nowhere. The resulting southwest flow will pump moist air into the Alex and Gaston Zone, allowing our hybrid Hazel system to develop Thursday into Friday and then steer north toward the Mid-Atlantic. Overall, it may appear that the rain began Wednesday, and didn't stop until Saturday night, but it will be two distinct storms over that period.

So take heart in this... Were the storm occuring in winter, and just a few more miles offshore, we all would have had two or three feet of snow when it was all done. Perhaps that an indication of what's in store this winter?

Sunday, October 10, 2004

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As the satellite photo above indicates, the tropics remain busy. This is a month of contrasts across the country weather-wise, as we have snow, tropical systems, and hot conditions all at the same time in different parts of North America.

This is also the month for the October Surprise. Not the sudden capture of Osama shortly before election day, although that would be a welcome relief, but rather those pesky little systems that blow up out of nowhere and catch even the seasoned NHC off guard. Cases in point include "subtropical storm Nicole" whatever that is, and Tropical Storm Matthew. That storm should not have been a surprise to any forecaster who has internet access and looks at satellite imagery. Anyone with eyes could have seen the building system in the SW Gulf.

So we have to remain suspect of any disturbed looking weather because unless a recon aircraft gets in there, you could have a tropical storm hiding in the clouds, and we wouldn't know it until official observations came back to verify, as was the case with Matthew.

Subtropical Storm Nicole is looking to slam Newfoundland with perhaps 50-60 mph gales and a storm surge of several feet. As you can see from the satellite, a lot of tropical moisture is waiting out there to go somewhere, and north is the place it is headed.

The area of disturbed weather at the bottom of a frontal boundary across Florida is looking to lurch into the "Alex and Gaston Zone." This is that region off the GA/SC coast where these two storms were turned into overnight disasters by the Gulf Stream. In both cases, the actual strength of the storm far surpassed that which was officially forecasted.

October 17 is the 50th anniversary of Hurricane Hazel, which ought to bring back a few memories for some. I will do an analysis piece later this week on why I am concerned about another surprise later this week as this new disturbance mentioned above reaches the "AG Zone." Upper air patterns are eerily similar to that of October 1954, which I will show you in a graphic later this week. This is the time of year that tropical systems can more readily morph into hybrid nor-easters due to the larger differences between cold and warm present in the atmosphere as we head toward winter. That's why Hazel could do so much inland damage late in the season back then.

So we cannot write off Florida as being in the clear from another strike (from the west), nor can we say the East Coast is going to escape without major impact. I think October still has a number of surprises left to show us.

Friday, October 8, 2004

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Tropical Storm / Depression Matthew is not going to become a hurricane, but it portends trouble down the road as the Gulf is becoming active and the waters remain warm.

Rainfall from this system surpassed 6 inches in many parts of Louisiana, and the Florida panhandle also got heavy rain and thunderstorms, which does not help much for those trying to clean up.

Here's a perspective... Escambia County Schools of the Pensacola area are scheduled to reopen on Monday, October 11 after almost a month of being closed due to Ivan. That means no Fall Break, little or no Christmas or Easter Break, and possibly extended school days. It's a good thing they don't have to deal with snowstorms, or they would never be able to finish the school year.

Monday, October 4, 2004

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The satellite image shown below is a growing tropical wave that is showing signs of developing.
It may not get named before it reaches the northern Gulf coast, and drench the area from eastern Texas to central Louisiana with several inches of rain and 25-35 mph winds.

That would seem to qualify as a tropical depression, but the NHC does not see evidence of a circulation or a deep enough pressure to classify it yet.

Beware the ghost of Opal, which in 1995 started out in the same area as a weak storm, and literally overnight did a this case going from a weak Category 1 to a strong 3 in the space of 6 hours, catching many in the Appalachiacola area by total surprise. October is the time of year for rapid development in the Gulf since water temperatures are now at their warmest of the entire season.

Otherwise the tropical Atlantic is quiet, only a few minor waves floating here and there.

May see the first frost of the season in PA and northern MD Tuesday or Wednesday morning. Overall, October is expected to remain above normal in temperatures, which portends good things for the powderhounds.