Scott's July 2008

Mid-Atlantic Radar

Scott's July, 2008 Blog
(blog descends chronologically)

Dolly May Be a CAT-2 At Landfall!
Wednesday, July 23

Unlike many hurricanes that weaken on approach to land, Dolly appears to be strengthening as she comes ashore right on the Tex/Mex border. Current view:

Enhanced close-up:

Pressure continues to fall and I've flight level winds at 91kts...these winds may have time to mix down to the surface. A hurricane hunter flight this morning found minimum central pressure at 968 millibars...that translates to a Cat-2 on the Saffir-Simpson scale. Surface winds have not caught up to this latest pressure drop by may do so prior to landfall.

National media is all over the storm's landfall and persons in the affected area now are hunkering down so we'll not cover the breaking news aspect of this event. However, TornadoVideo Net is now attempting to set up a live stream from near South Padre Island and if that's online I'll link it at our HurricaneCenter so keep an eye on real-time developments there.

INVEST 97L: While Dolly is the Big Show, a new wave came off Africa yesterday and is now Invest 97L. The wave is zooming along at 20MPH but is showing now sighs of immediate development. We'll keep an eye on it but for now it remains an open wave near the Cape Verde Islands. Very early start to "CV Season" this year.

WEDNESDAY AFTERNOON UPDATE:

1:30PM (12:30PM CDT) Dolly making landfall over South Padre Island, TX. NOT REAL-TIME.
Click image to enlarge

Radar credit: WeatherTap.com

As opined here earlier this morning, Dolly is now a Cat-2 although I've not yet seen Cat-2 surface observations. Even in image above the eyewall erosion is visible and we turn attention soon to huge rainfall...especially just north of center. Estimates are printing out totals up to 15 inches of rain in some locations!

Dolly Looks Like She's Ordering Tex-Mex.
Monday, July 21

Dolly did a wiggle-wobble dance over night, just clipped the edge of the Yucatan Peninsula and is now over water.

Current view:

With land now out of the way and almost no wind shear, Dolly may begin ramping up over the Gulf. NHC intensity forecasts currently bring her to a Cat-1 prior to landfall near the Tex-Mex border late Wednesday night. High Pressure Ridging *should* restrict Dolly's progress to the North...meaning the center is not expected to head up towards Galveston/Houston. Obviously, people in the potential path need to get their emergency preparations underway immediately. Time is the enemy of Dolly as it's doubtful she has enough to blow-up into a major hurricane...but that is not known at this time. In any event, the storm will make landfall and northern Mexico/Southern Texas coast is the likely target. Rough surf and increasing winds certainly will migrate northwest well ahead of the tropical cyclone so folks well up past Galveston should prepare for this advance feature of the storm.

No changes to thinking outlined below with regard to Cristobal.

Cristobal Cruising Past OBX While Dolly Decides Where to Go.
Sunday, July 20

Greetings from Boy Scout Camp! Well, almost...there's no Internet at camp so I'm nearby for a quick update.

Cristobal: Center is literally paralleling the lower Outer Banks with the center appearing to be just SE of Cape Hatteras. Reminds me of Ophelia in 2005 when she danced literally just off the lower OBX. My guess is Cristobal will score a "miss" for NC and ultimately will be a fish storm.

As mentioned, I don't have all the usual weather tools but am able to get radar and satellite via cell phone at camp. I'm surprised by the dearth of convection over land with the storm and can only surmise dry air intrusion and the trof over the interior Mid-Atlantic has done its dirty work. The storm has featured a nice convective burst this evening and winds have increased but remain strongest in the eastern quads...over water. Models zip the storm away with a breezy and rainy glancing blow to Cape Cod and DownEast Maine.

Dolly: Is everyone tired yet of the "Hello, Dolly!" 1-liners? Looking at Radar on my cell, it appears there's a typical nightly pop of convection tonight with Dolly as she heads for the Yucatan. What I can't tell, however, is if the center of circulation (COC) is jumping to the North. Being handicapped out here, I'm not sure if there are mid and low level centers of if there's reforming to the north and the storm is cranking up. This would not be good for western Cuba and interests along the western GOM. If the latter, this storm is not going to peak at just 45 kts prior to an expected Yucatan landfall on Monday. Dolly could sneak into the GOM by passing straight through the Yucatan Channel...not good! I'd sure like to know where the inflow is located right now! This storm worries me and when I'm briefly back in civilization on Monday I'll post here on the blog to see how we stand. These nighttime convective bursts can rapidly drop pressure and "jerk" a storm's center along a new track...so this must be closely monitored. If the center (wherever it is) doesn't make landfall on the Yucatan, many options will be on the table.

I'll try to have an update here on the blog by early afternoon. Back at camp tomorrow night so the schedule is tight, but check back in the afternoon!

Housekeeping: I noticed over 18 folks logged in for chat last night by I wasn't able to talk back. I'll work on that before doing "Take 2". Have a good night

"Cristobal" Coming to Coastal Carolina.
Invest 94L Remains Potential Gulf Threat Next Week.
Saturday, July 19

T.D. #3: A little more organized this morning and expected to strengthen today. NHC indicate this could become Tropical Storm Cristobal later today. By the way...if/when this becomes named you can be the first on your block to know the correct pronunciation: "krees-TOE-bahl". I'm sure alot of TV types will call the storm "Chris-toe-ball" and I'd wager it won't take someone on Fox long to call it "Crystal Ball".

Current satellite:

This morning's 12Z run of models shows excellent agreement in keeping the center off shore (Carolina hugger). This track is quite similar to what we see in winter with Nor'easters...however...a continued NE track is forecast after the storm clears the Outer Banks. An approaching Cold Front will help keep the storm away from land and there should be little impact north of the Chesapeake Bay. A caveat to this would be up around Cape Cod where the Cape and Islands could get some wind, rain and elevated surf late Tuesday.

The system obviously is extremely close to land and this hampers intensification. Proximity to land enhances dry air intrusion that will also keep the storm from rapid intensification. Water Vapor image (darker colors denote drier air):

The NHC Forecast/Advisory brings max winds up to 40MPH with gusts to 51MPH. With strongest winds in the Northeast quad, the stronger gusts should mostly stay offshore. Rain, some lines of marginally severe thunderstorms and gusts will be the primary features for central and coastal Carolinas as the storm heads up toward Cape Fear.

24 hour rainfall map below might be low if T.D. #3 becomes a tropical storm, but heavy rain still is not anticipated west of the I-95 Corridor.

Cool Web Cams!
14th Ave. Pier streaming Web Cam, Myrtle Beach, SC
James Island Yacht Club live stream
Wrightsville Beach, NC streaming web cam

INVEST 94L: Conditions now becoming favorable for development and the Invest will likely become T.D. #4 later this weekend. Pesky Upper Level Low (ULL) moving away will reduce shear as the storm hits warmer water. Most models track the storm toward the Yucatan Peninsula where it will become disrupted. There certainly is potential for low level circulation to survive the trip and emerge over the Western Gulf of Mexico next week. Models bring the storm anywhere (and everywhere!) from Veracruz to NOLA so we'll need development of an actual Low Pressure center before narrowing down that huge spread of options. It *appear* likely the storm will stay on a generally NW track near Merida, Mexico on the Yucatan.

The 6Z GFDI brings a major hurricane near Galveston while the HWFI goes bonkers with a Cat-4 aimed at the TX/MX border! The intensify the storm significantly due to little interaction with the Yucatan...way too early for that speculation but we'll certainly need to closely monitor developments should Invest 94 become a tropical depression.

An Invest a Day in the Atlantic!!! 2 Storms to Watch NOW!
UPDATE: INVEST 96L Being Upgraded!
Friday, July 18

Very brief post this morning as I'm away from the office. My son and I were in an auto accident (no injuries, thankfully), so I've been renting and bumming cars the last several days to keep up with scheduled work. As such, it's been tough to post this week. I'll have a more in depth blog tonight.

Four systems in the Atlantic! The two to watch are Invest 94L, now located in the Caribbean, south of Hispaniola and Invest 96L...just off the GA coast. NHC did me a huge favor and released a Special Tropical Disturbance Statement on these events :) I'll post here and follow-up tonight:

NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1125 AM EDT FRI JUL 18 2008
THIS STATEMENT CONCERNS TWO TROPICAL WEATHER SYSTEMS.

SATELLITE IMAGES INDICATE THAT THE AREA OF LOW PRESSURE LOCATED IN
THE CENTRAL CARIBBEAN SEA ABOUT 400 MILES SOUTHEAST OF JAMAICA
CONTINUES TO BECOME BETTER-ORGANIZED. AN AIR FORCE RESERVE UNIT
RECONNAISSANCE AIRCRAFT IS SCHEDULED TO INVESTIGATE THIS SYSTEM
THIS AFTERNOON TO DETERMINE IF A TROPICAL DEPRESSION OR TROPICAL
STORM HAS FORMED. ALL INTERESTS IN THE CENTRAL AND WESTERN
CARIBBEAN SEA SHOULD CONTINUE TO MONITOR THE PROGRESS OF THIS
SYSTEM AS IT MOVES WESTWARD AT 15-20 MPH. FOR INFORMATION SPECIFIC
TO YOUR AREA...PLEASE CONSULT STATEMENTS FROM YOUR LOCAL WEATHER
OFFICE.

SURFACE OBSERVATIONS AND SATELLITE IMAGES INDICATE THAT
A LOW PRESSURE SYSTEM LOCATED JUST OFF THE COASTS OF GEORGIA AND
SOUTH CAROLINA IS ALSO BECOMING BETTER ORGANIZED. ENVIRONMENTAL
CONDITIONS ARE CONDUCIVE FOR FURTHER DEVELOPMENT...AND A TROPICAL
DEPRESSION COULD FORM TODAY OR TOMORROW. AN AIR FORCE RESERVE
HURRICANE HUNTER AIRCRAFT IS SCHEDULED TO INVESTIGATE THIS SYSTEM
TOMORROW...IF NECESSARY. ALL INTERESTS ALONG THE COASTS OF
GEORGIA...SOUTH CAROLINA...AND NORTH CAROLINA SHOULD MONITOR THE
PROGRESS OF THIS SYSTEM. LOCALLY HEAVY RAINFALL IS POSSIBLE IN
THESE AREAS DURING THE NEXT COUPLE OF DAYS AS THIS SYSTEM MOVES
SLOWLY NORTHEASTWARD NEAR THE COAST. FOR INFORMATION SPECIFIC TO
YOUR AREA...PLEASE CONSULT STATEMENTS FROM YOUR LOCAL NATIONAL
WEATHER SERVICE FORECAST OFFICE.
$$
FORECASTER BLAKE/KNABB

Current location of all Atlantic and Eastern Pac systems:

Maps on all storms and Invests are online at our HurricaneCenter.

We're running exclusive model maps on four Atlantic storms and two Eastern Pac storms. Information on subscribing to our model maps is HERE.

FRIDAY NIGHT UPDATE:

Pardon me while I check the calendar...is it early September and peak-week for hurricane season?

Let's dispatch the easy stuff fast:

Invest 95L: The storm has sloshed into Central America and is dropped.

Bertha: Talk about Girls Gone Wild! As Edwin Starr sang in the song "War": Good God y'all! Bertha just won't go away...in fact she's a hurricane once again. Already the longest lived July storm, Bertha will remain a Cat-1 for a relatively brief time span, perhaps into Saturday evening. She'll then continue the transition into an Extratropical cyclone and eventually approach Iceland. Bertha's forecast track map HERE. Bertha's first Advisory was on June 30. Sheesh!

Invest 94L: Hurricane Hunters flying into the Invest this afternoon did not find a closed surface circulation...one of several mandatory minimum requirements to classify an Invest as a TD or storm. Tonight, the system looks pretty impressive!

Click HERE and you'll see a fairly well defined spin. That rotation is in the mid-levels and if it makes it down to the surface we'll have a TD or possible a Tropical Storm this weekend. Models keep the Invest south of Cuba and on track toward the Yucatan...we'll see if that holds or if guidance shifts more to the NW. Weakening High Pressure over the Southeastern US will be followed by a Cold Front so it does not appear likely the storm will track Northwest (over Cuba and into the central/eastern GOM). It is too early for that decision but the Yucatan, western Cuba, Jamaica and eventually the western Gulf could all be on the playing field in the not so distant future. This system must be monitored closely over the next several days.

INVEST 96L being UPGRADED: The blob off the GA/SC coast is an organizing storm currently labeled Invest 96L. I thought there was a chance NHC would upgrade at 5PM but they did not. A quick check with NHC reports Invest 96L is about to be classified as a Tropical Depression or storm.

Check our HurricaneCenter tonight as the NHC is expected to begin issuing Forecast/Advisories at 11PM. Models trend toward bringing the storm up towards OBX and then they diverge. Costal interests south of the Chesapeake should prepare for stormy weather. If this stays just off shore it will produce rough surf and wind along the coastline and very heavy rain inland over the Carolinas and into Virginia.

More on Invest 94L and this coastal "sneak attack" here at the blog on Saturday morning.

Invest 94L: Interesting Next Week.
Sunday, July 13

BERTHA is "The Thing That Wouldn't Leave"! After getting near Bermuda a breakneck speed, the cyclone is crawling and is forecast on a genuine rollercoaster track. Key point is while Bertha is just east of Bermuda and will NOT make landfall, it WILL continue causing problems over the next 3 days. Feeder bands certainly will pummel the island as the storm approaches and then is forecast slowly pull away to the NNE. A couple models bring the storm back to Cat-1 hurricane strength...if this happens it will be the rather unusual as tropical cyclones typically do not regain hurricane strength this far north. Nonetheless, a very damaging event for Bermuda with impacts well to the west. I earlier spoke with my daughter who was at Virginia Beach and she commented swells were 3-4 feet. While manageable, it demonstrates the impact a hurricane can have even while well offshore.

INVEST 94L: This new system came online today and you'll get current info here at our HurricaneCenter. The Invest is about midway in the Atlantic Ocean and while the models aren't jumping all over it, there is potential! There's no wraparound convection but conditions will support development over the next couple of days and my hunch is this will become a Tropical Depression by Wednesday...possibly sooner. Most computer guidance brings a weak storm towards the Lesser Antilles or Leeward Islands by next weekend. I'll again remind you the intensity forecasts have not been good this year and this will continue with Invest 94L until there is some sustained circulation. Interests in the Caribbean and Florida certainly should monitor this storm; it obviously has more potential to threaten land than does Bertha. For now, forecast models and sensible weather show the Invest will track generally to the WNW. I won't speculate on strengthening at this time except to say the Invest 94L is expected to become a Tropical Depression.

Folks interested in our exclusive model maps can get information here. Keep an eye on this Invest!

Ba-Bye Bertha! *Probably* a Fish Storm.
Tuesday, July 8

Current NHC Forecast/Advisory continues to recurve Bertha east of Bermuda. Every model except the BAMS keeps Bertha well away from any land over the next 5 days. As such, it now appears extremely unlikely the powerful, but weakening, tropical cyclone will affect the US. The GFS model now is right in line with the NHC "black line". Good news as Bertha developed into an intense early season hurricane.

Pesky weather over the Mid-Atlantic is part of the reason the hurricane is fully expected to remain well off-shore. A nagging Upper Level Low has been parked over Virginia. Click here for water vapor loop. The disturbance will trigger another day of pop-up storms today...some strong to severe. As an aside, there was a very small but strong thunderstorm here in Lexington, VA shortly before 3AM this morning. Our lightning detector was recording 100+ strikes/minute within a 25 mile radius. While our equipment is well protected by surge suppressors, the lightning was so vivid and so close that I unplugged all computers and telephones and avoided windows during the height of the storm. You KNOW there's dangerous lightning when I do that!!!

Back to Bertha. An approaching Cold Front will help this Low and trof over the Mid-Atlantic to migrate east today. The front will be advancing on Bertha this weekend and that builds confidence the gate is closed and the storm gets stuck out in the Atlantic. High Pressure over the Mid-Atlantic States will give way to another front later in the weekend and that should ensure the cyclone remains over the open waters.

The storm will have some affect on Bermuda and the Mid-Atlantic and Southeast coast later this week as building swells and higher seas will advance on the coastline.

Never one to let my guard down, I think we can feel good this impressive hurricane will stay away from land, but it should not be ignored.

The GFS is trying to develop the most recent wave that rolled off Africa. All else is quiet in the tropics.

Bombs Away! Bertha Becomes a Cat-3 Hurricane.
Monday, July 7

Bertha "bombed out" today quickly ramping up from a tropical storm to a major Cat-3 hurricane. Here's a real-time satellite view (click image for more). Note the extremely impressive eye...particularly for early July.

To cut to the chase...only the GFS differs from otherwise excellent model agreement that takes the center well east of Bermuda. The GFS has been good so far this year and it being the new outlier bothers me...especially as it brings the storm toward the Carolina Coast! However, the reliable UKMET (EGRR on our model maps) has come around to other models and is well within the NHC's Cone of Probability. All eyes will be on this evening's 0Z GFS and if the model comes back in line this in all liklihood will be a "fish" storm with outer western quads impacting Bermuda.

Bertha is now slowing down and moving more to the northwest and this is a trend that should continue over the next 36 hours. This track become favored once the storm underwent rapid intensification. If you read the previous two blogs on Bertha, this is the first of two options discussed below

So, while it *appears* Bertha will fish east of Bermuda, it would be irresponsible to stick a fork in the storm...especially with the 18Z GFS. Thus far, the GFS and UKMET (despite yesterday's aberration) are doing well this season. Our exclusive model maps run Ensemble (consensus) models along with the numericals and I'll note the CGUN (corrected GUNA consensus) has done well. As usual, the NHC has provided excellent service to the public.

The critical component in forecasting the hurricane is the anticipated trof of Low Pressure coming out off the eastern US this week. The hurricane center (and most models) see the trof shift the Bermuda High east while catching Bertha...out to sea. Looking at the 18Z GFS, it projects a weaker boundary that fails to dig south enough to influence the storm. Is the GFS seeing something that otherwise is being missed? My gut says no...but...a more westerly track remains a very small but possible option. As such, the East Coast needs to closely monitor the hurricane. Stay close to current information at our HurricaneCenter.

Think hurricane forecasting is easy? Honest quote from this afternoon's 5PM NHC Discussion:
BERTHA'S INTENSIFICATION TO MAJOR HURRICANE TODAY HIGHLIGHTS THE DIFFICULTIES OF FORECASTING RAPID INTENSITY CHANGES.
Well said.

HOUSEKEEPING: Our weather station has been offline since this morning at 7:40AM. I can't get a human being on the phone but there's an issue somewhere with Comcast (ISP for our wx station and email). This problem doesn't affect the web site server or our Premium Service hurricane model maps.

Quick update here at the blog on Tuesday morning. Have a good night.

Bertha Barreling Along Toward Bermuda and US East Coast.
Sunday, July 6

It's been a while since we have contended with an Atlantic hurricane storm tracking into the US East Coast. Alex/04 clipped the OBX, Charley/04 devastated Florida before a 2nd landfall near Myrtle Beach. In 2005, Ophelia tracked along the NC coast. One can make the case the East Coast hasn't had a serious landfall threat since Isabel in 2003. I always wonder how many people on the East Coast now believe hurricanes occur only in the Gulf.

I doubt Bertha will hit the US mainland but do believe there are many reasons to think she'll be a strong tropical storm or Cat-1 hurricane southwest of Bermuda next weekend. If so, we certainly have the first serious threat in the Western Atlantic in some time.

This morning, Bertha is still tracking west at a speedy 18MPH. She is a small storm with strongest convection still displaced to the north of her actual center. Storms fired up to the south this morning and we'll see if they hold into this evening. Wind shear aloft would hamper a stronger storm but this isn't the case with Bertha. She is now getting over water warm enough to support some intensification...and this is reflected in NHC's Forecast/Advisory of Bermuda.

Here's a look at this morning's 6Z GFS (click graphic to enlarge):

Bertha's position is the "1012" area of Low Pressure. Note the large High Pressure Ridge over the Atlantic...this will steer the storm west/west northwest over the next few days.

Here's how the GFS sees things next Friday morning (click graphic to enlarge):

You'll see two Highs over the Atlantic and Low Pressure over the Canadian Maritimes with a frontal boundary moving off the East Coast. This set up would probably introduce a more northerly component into her track...bringing the storm up near Bermuda in one week. Several models (notably GFS, GFDL and NOGAPS) slow down the storm...that gives time for the trof of Low Pressure to move offshore. If all this pans out, Bertha misses the US and threatens Bermuda. The UKMET (EGRR on our model maps) continues to be the outlier with Bertha more to the south and west of the NHC forecast track. Normally, this would worry me, however, the model is now trending more in line with the overall consensus o numerical and ensemble models.

Many variable are in play so there's no guarantee with a tropical cyclone located in the middle of the Atlantic and one week away fror possible landfall. While I'm skeptical Bertha gets close to the coast, it is impossible for anyone to know that at this time. Keep an eye on our HurricaneCenter for current information and check back here at the blog. Emergency plans and preparations should be complete for every home and business that could be affected by a tropical cyclone, so we always urge folks to review their plans!

Next update here at the blog will be Monday afternoon.

Tropics Begin Bubbling...And...Bertha's Possible Threat.
Friday, July 4

I've been out at our local Boy Scout camp but have been able to keep an eye on all developments this week. Yesterday saw five systems: 3 in the Eastern Pacific and two in the Atlantic Basin. In the EPAC, all named storms (Boris, Christina and Douglas) have had the final Forecast/Advisory issued. Invest 97E is weak and disorganized, so any development is unlikely and would be slow. In the Atlantic, Invest 93L was located near the Lesser Antilles and had no chance due to wind shear.

Visit our HurricaneCenter for location of all storms and Invests. If you're interested in our exclusive hurricane model maps please click here.

This brings us to Tropical Storm Bertha. A strong wave rolled of Africa Monday night and has now developed into a 45MPH tropical storm. Such storms are referred to as "CV (Cape Verde) waves. Bertha's impressive development this early in the season not only is record breaking, it bears watching. The only July storm that formed near Bertha was Caesar/1990:

Bertha organized further East than did Caesar, making it the easternmost July tropical cyclone on record!

What's next? Bertha's minimum central pressure has dropped only 6-7 millibars in the past 24 hours...so she is not undergoing rapid intensification. But, despite relatively cool water, thunderstorms are refiring and the pressure is dropping. Forecast in the short term is straight forward: generally WNW until the storm reaches 50°W on Monday night. Then, Bertha will decide where she goes! If Bertha becomes a well organized storm or hurricane it is likely she'll recurve and be a "fish" storm. This is because High Pressure to the north will help steer her around the Ridge, where she'll be scooped up by an approaching trof. The other option is Bertha remains a relatively small storm that would not be steered to the Northwest and remain south of the trof...meaning she continues tracking towards the Islands. At some point, wind shear from the migrating Jet Stream should do her in...might be Southeast of Bermuda or further south. Something of interest: the GFDL/GFDI have been good with Bertha thus far and recurve her away from Bermuda as a hurricane next week. There are many options so we're confident on the weekend track, we'll see how things look on Sunday.

UPDATE: 11:20AM. 11AM Forecast/Advisory (#6) has shifted the track "down" more to the southwest of previous packages. NHC keeps the Bertha a tropical storm for the next five days. Should this become a trend, the second option above would become more likely to verify.

Speaking of looking...my daughter sent me this cell phone picture from the family's home in Lexington, Virginia. Each year there's a big hot air balloon rally and fireworks at Virginia Military Institute and the evening breeze always brings balloons right over the neighborhood. By the way, there are three balloons in the picture...did you spot the one landing?

Keep an eye on the sky for more than just fireworks as some storms are forecast over the Mid-Atlantic this afternoon and again on Saturday. Some localized thunderstorms could become strong with winds and small hail as the primary threats. Check into our Severe WeatherCenter for information over the weekend.

Next blog on Sunday unless thing change in the tropics. Have a happy and safe Independence Day weekend!

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