Saturday, July 5, 2008

6 comments:
DOUBLE TROUBLE AHEAD:
1. CAPE VERDE TROPICAL STORM...RECURVING?
2. INSTABILITY IN THE WESTERN GULF

Atlantic Basin 7-4

SAT 7-5 AM UPDATE: The Tropical Atlantic is starting to produce noticeable activity, view the latest infrared satellite loop. As of 11AM Thursday morning, the robust tropical wave off the West African coast was upgraded to Tropical Storm Bertha, and may approach hurricane strength late in the weekend.

SYNOPSIS: Bertha is the first named tropical storm known to have developed this far East in the Atlantic. At present, upper level air flow patterns indicate that a landfall on the U.S. mainland cannot be ruled out. In the southeast Caribbean, a weak area of low pressure had been producing scattered showers and thunderstorms, but remains disorganized. However, activity continues to flare up west of the estimated center as the overall system drifts west-northwestward. A broad area of showers and thunderstorms is also present near the coastal Texas/Mexico border and will be monitored this weekend.

Bertha 3

FIRST, THE CAPE VERDE SYSTEM: View this enhanced infrared loop. Ironically the last notable tropical cyclone to form in this region at this time of the year was...Bertha, in July 1996. With a classic summertime Bermuda High ridge forecast to start building next week, one might initially think the storm could travel under the ridge and in the general direction of the Caribbean. When considering the air flow at upper levels, a different trend is revealed, and you would see why some computer models are indicating recurvature east of Bermuda. A brief explanation for this is provided in the "upper level analysis" section. Below is the current NHC projected path from 5PM 7-4, and preceding it is the 11AM Advisory.

Bertha 2

Notice the westward shift in the cone of uncertainty from one map to the next.

NHC Bertha 2

UPPER LEVEL ANALYSIS: This next map is among the many new features I've been learning about in my Weather Forecasting and Climate Change class here at the picturesque College of the Atlantic. As I experiment with a new feature or skill from the class, it will be added here for use during this year's hurricane season. The newest (to me) resource is the 500 mb 24-hour forecast for the Central and North Atlantic issued by the Ocean Prediction Center. The inference I am making from this map is that once Bertha nears the Low and High progged at the 500 mb (~18,000 foot) level, the air movement between these two centers will create convergent flow south to the south side, with air diverging on the north side. This will act to pull the system toward the vacuum created by this flow, and begin curving the storm northwest and eventually northward into the central Atlantic. The NHC refers to this as a weakness in the subtropical ridge. This is an example of the importance of knowing movement of air masses and pressure differences at upper levels, which ultimately dictate what is observed on the surface for us ground observers.

Atlantic 500MB 7-3-08

BACKGROUND: A tropical wave developing off the West African coast is referred to as a "Cape Verde" system due to the promixity of an island cluster of the same name. Were this occuring between mid August and late September, we would have great cause for concern. This early in July, waves way out there usually don't become the Katrinas, Ivans, Floyds or Glorias and come terrorizing the Gulf or East Coast. Each tropical season, one hundred or more disturbances drfit off the African coast and cross the Atlantic. In July 2005, two of these systems reorganized once near the Caribbean and developed into named storms. Dennis made landfall as a Category 3 Major Hurricane on the Florida panhandle July 10 of that year. Just eight days later, Emily has already crossed the same southern Caribbean waters, and struck the Yucatan on July 18 as a Category 4. Emily also had a second landfall south of Brownsville in Northeast Mexico as a Category 3. I realized in reviewing the archives on both storms...back on July 6, 2005 the Atlantic basin had nearly an identical setup: A tropical wave just off the African coast (which would become major Hurricane Emily), AND a small feature in the southern Caribbean which became Dennis.

SECOND: THE SOUTHERN CARIBBEAN SYSTEM. View the latest satellite loop. While the system is being sheared by upper level winds, it is also about to enter surface waters nearly 2 deg F above normal, and low level steering currents favor a west-northwest path for the next day or so. Despite the shearing, thunderstorms continue to flare up west of the center. Closer examination of the environment ahead of this wave is warranted over the weekend. Any system named in that region of the Atlantic Basin this time of year will be a cause for concern among emergency management officials, cruise operators and the especially oil market. In fact, I suspect that many astute futures traders are watching this area closely For an even more serendipituous perspective on the economics of hurricanes, consider investing in the Hurricane Futures Market, as first reported by MSNBC in 2005. As Dave Barry would say, "I am not making this up."

Invest 93L Satellite 7-2

While this system has decated, compare the earlier projected path to the NHC official tracks for Hurricane Dennis in July 2005, as recorded in this link to the archives for that period.

Invest 93L Preliminary Model Tracks

Under the training from our Weather and Climate Instructor, I've gained a new appreciation for the importance of applying real time interpretation skills to existing atmospheric data. I've spent the learning from Dr. Lou McNally, who with 30 years service across in both the private and public forecasting industry, is a super-rich source of knowledge and we are very fortunate to have him take time out of his crushing schedule to shepherd us through the nuances of weather analysis. Thanks Lou, for making this a highly informative, useful and thought-provoking class thus far! For me it is uniquely fun and beneficial, as I have been implementing the skills learned in class almost immediately, and hopefully those of you following this site will see the payoff in a better understanding of what drives the weather.


PREVIOUS UPDATE- WED 7/2 4:30 PM. From beautiful Bar Harbor in Downeast Maine, I wish you all a safe and weather-friendly Fourth of July Weekend. I shall have the day off from my Weather Forecasting and Climate Change course here at College of the Atlantic. If our class forecast for the weekend holds true, then I plan to revisit Acadia National Park via the island bus service and take my rented mountain bike with me. During lunch each day, I take a short bike into the wonderfully quaint town that is Bar Harbor (yes I will post pictures soon). On Tuesday 7/1 my classmates and I journeyed atop Cadillac Mountain for incredible views of the Maine coastline as well as cloud and front analysis. At 1,530 feet, this mountain is the highest point directly on the Atlantic coast north of Brazil, and it is quite a sight to look out into the ocean from it's summit. Thank you to the well-wishes of those whom have made Bar Harbor among their vacation spots, and I can now see why you think so fondly of this place. As I pedal through the rustic and unique downtown, I think fondly of all you as well and wish you along with my family could be here to enjoy the sights, fresh Atlantic air, and great people that comprise the wonderful region known as "Downeast Maine."

Friday, July 4, 2008

3 comments:
THE BEAUTY THAT IS DOWNEAST MAINE
FRIDAY 7-4 UPDATE: CHECK THIS SECTION FOR NEW PICS IN THE WEEK AHEAD

Forecaster Foot finally makes it to Downeast Maine
One of many rugged inlets found along the coastal section of Acadia's Park Loop Road.


A view familiar to many of you: The islands of Frenchman Bay from atop Cadillac Mountain

I cannot recall the name of the islands shown... something about the "Sleeping Lambs?"
Those of old timers with more background on the Barbor will know in an instant I'm sure.


College of Atlantic's "Seaside Garden"
Where I'll be posing for the cover shot of next month's issue of Cottage Living... a beautifully serene place in front of the College's Administration building, known as the Seaside Gardens.
College of the Atlantic, Bar Harbor, ME

Starting Sunday, June 29 I will be spending two weeks at Maine's College of the Atlantic in Bar Harbor (or as I have learned, is pronounced 'Bah Hahbah'). What am I doing in Maine you ask? I am enrolled in a 4-credit graduate course to enhance my background and understanding of weather forecasting and climate change! Sadly I have to celebrate my 12 year anniversary away from my lovely wife and little Foot girls, but to reassure all the Moms and wives out there, I did leave Mrs. Foot a very nice card with special hand written messages inside. Originally the ladies were going to accompany me on this journey, but a number of complicating factors...including the price of fuel, scuttled those plans. But we may try again next year so we can all attend the Family Nature Camps.


The other real reason I'm here is that this course is part of a year-long process to complete the outstanding credits required to maintain my Maryland teaching certificate. So it may come as a shock to you (although my students already know) that I am taking a one year leave of absence from teaching to finish the credits and lock that Master's Equivalency under my belt.


An All-Forecaster-Bulletin: Mr. E.H. of Woburn, if you're out there and not already on vacation, please contact me via the comments as soon as you can. I would have contacted you by email, but lost the address when my previous computer checked out. I'll be in the Boston area Sat/Sun July 12 and 13 and it would be a real honor to finally meet you, have lunch and revel in the wonderful New England scenery and summer weather. I'll be sure to post some pics of the experience in Bar Harbor as well as new insight gained on upcoming trends for the hurricane and winter storm seasons.
CollegeoftheAtlantic

Saturday, June 28, 2008

10 comments:
"IT HAPPENED BEFORE...IT WILL HAPPEN AGAIN.
It's just a question of W H E N."
- voice of Charleton Heston, in the opening scene from Armaggedon.
1. EXCESSIVE HEAT DISMISSALS. June 28 followup comment: The call made on June 5 played out in Baltimore County Schools as expected, with a 3 hour early dismissal due to heat on Monday June 9. am wagering that many county school systems in central Maryland and Northern Virginia will be forced to close 2 - 3 hours early this coming Monday. It's actually not about the daytime high..but rather the overnight low. If you arrive to school at 7AM Monday with a morning temperature already at 80 F in 90% humidity, it will not take long for regular daytime heating to boost that up to 90 before lunchtime.


2. ISABEL WAS ONLY A REHEARSAL. The current weather pattern I believe is a continuation of what I explained to many people at my school and elsewhere. The Mid Atlantic would experience a fairly cool and drawn out spring, with temperatures staying at or below normal. Then come early June, we would race into the 90's and stay above normal into July. The traditionally hottest periods of the year..late July into early August, may in fact be cooler than normal, and that I am concerned might setup a persistent upper level trough along the East Coast. With La Nina now backing off and the possibility of even switching over to a weak El Nino, this whole scheme is looking eerily similar to the summer of 2003. Were the Bermuda High to back off into the Atlantic come September, and a weak trough establish near the coast, this has the potential to steer any western Atlantic tropical systems toward the Eastern seaboard. Since 2003, I have been telling hurricane watchers and many others that Isabel was truly just a rehearsal, and the bigger threat is a 1933 type Category 2-3 storm that travels up the west side of the Chesapeake Bay. You know what Mr. Heston said, right...


3. SUNSPOTS, PACIFIC WATERS AND POLAR SEA ICE. These are three major influences on Eastern US winter weather that will be receiving top-billing on this site over the next 6 months. Were you to combine the upcoming sunspot cycle minimum (decreased solar output this winter) with a switch over from a currently fading La Nina to a possible weak El Nino, and a rapid return of Northern Hemisphere snowcover and polar sea ice...what do you have? I believe these three factors point to a less-than-active hurricane season followed by above normal snowfall for the Northeast and Mid-Alantic. My overall projection for this region is that this coming winter will more than make up for the lackluster performance of the previous two and closely resemble 2002-03. You all no doubt remember that season featured the February President's Day Blizzard (remembered now as "PD II" ) among many other heavy snowfalls in the I-95 corridor. I remember it well for the 9 snow days in the Baltimore County Schools.