Monday, June 30, 2014

Tropical Depression One Forms Off Florida Coast; Tropical Storm Watch Issued for Parts of Florida

Published: Jun 30,2014, 10:58PM,EDT weather.com
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Tropical Depression One in the Atlantic

Key Takeaways

  • A tropical depression has formed off the Florida coast, and is expected to strengthen.
  • A tropical storm watch is in effect from Fort Pierce north to just south of Flagler Beach on the east coast of Florida.
  • This system will likely track near parts of the Eastern Seaboard, particularly from Florida to North Carolina, this Fourth of July holiday week.
  • All residents from eastern Florida to the Mid-Atlantic coast and far southeast New England should monitor the progress of this system.
Tropical Depression One has formed about 100 miles east of Cape Canaveral, Florida. It's the 2014 Atlantic hurricane season's first tropical depression.
It is still experiencing some light northerly wind shear, displacing thunderstorms somewhat from the center of circulation. There is also some residual dry air lurking to the north and northeast of the fledgling surface low. Most thundershowers associated with this low had stayed off the coast, but are now pushing into the northwest Bahamas and will scrape the Florida coast generally south of Cape Canaveral over the next several days.
(INTERACTIVE LOOPS: Radar | Satellite)
This low is currently caught in an environment of weak steering winds aloft, so it is likely to loaf and lollygag near or off the east coast of Florida and north of the northwest Bahamas through Tuesday.
However, it is also situated over the Gulf Stream, a ribbon of warmer water off the Southeast U.S. coast. Furthermore, the somewhat hostile conditions (wind shear, dry air) limiting the system's organization the past few days are expected to lessen. The longer the low hovers and percolates convection, the more possible it is for the convection to organize around the center and begin the process of intensifying the tropical cyclone.
The first named storm of the 2014 Atlantic hurricane season is Arthur.
Background

Projected Path

Projected Path
Above: The latest forecast path and wind speeds from the National Hurricane Center.
By Wednesday or Thursday, an approaching cold front and southward dip, or trough, in the jet stream, in concert with strengthening high pressure near Bermuda, are expected to pick this system up and steer it toward the north then northeast.
Eventually by late this week, the system will take a sharper northeast turn out into the open Atlantic, as the jet stream westerlies exert their steering influence.
There are several key lingering uncertainties at this time:
  • Will the low strengthen over the ocean before it's picked up by the trough, or will it actually drift southwestward over the Florida Peninsula before turning toward the north-northeast, lessening the chance of it intensifying?
  • If it stays over water, how close to the coast will the system track and how strong will it become?
  • How far will it track up the East Coast before making the turn farther offshore?
Uncertainty this far out in time is typically high, as depicted in the forecast model tracks image below. However, the general scenario outlined earlier is of higher confidence.
Whether this becomes a heavy rain, strong wind, coastal flooding/beach erosion, high surf and rip current threat at any given location depends on all these uncertainties in both track and intensity. It is still a bit too far out in time to make any definitive calls on potential impacts later this week.
Interests along the coast from eastern Florida to the Mid-Atlantic coast and even far southeast New England should monitor the progress of this system as we head through the Fourth of July holiday week.
(FORECAST: Jacksonville | Charleston | Myrtle Beach | Outer Banks | Va. Beach)
We have additional current status and forecast maps below, including watches, warnings, satellite imagery and model track forecasts.
Background

Storm Information

Storm Information

Current Information

So, where exactly is the cyclone's center located now? If you're plotting the storm along with us, the information depicted in the map above provides the latitude/longitude coordinates, distance away from the nearest land location, maximum sustained winds and central pressure (measured in millibars).

Background

Watches/Warnings

Watches/Warnings

Tropical Storm/Hurricane Watches/Warnings

A tropical storm or hurricane watch is issued when those conditions are possible within the area. Watches are typically posted 48 hours in advance of the onset of tropical storm-force conditions, since preparing for the storm becomes difficult once tropical storm-force winds begin. A tropical storm or hurricane warning means those conditions are expected in the area. Warnings are typically issued 36 hours in advance of the onset of tropical storm-force winds. When a warning is issued, you should complete all storm preparations and, if directed by local officials, evacuate the area immediately.

Background

Model Track Forecasts

Model Track Forecasts

Model forecast tracks

The various tracks shown in the map above illustrate possible tracks of the center of the tropical cyclone from various hurricane forecast models. The degree of spread in the tracks reflects the degree of uncertainty in the track of the tropical cyclone. A tight clustering of tracks can signify a higher-confidence track forecast compared to a large spread in model tracks. None of these tracks are the official forecast track. That is shown, instead, by a forecast path, cone or swath, illustrating an uncertainty in the future track. Also, the impact of any tropical cyclone can stretch well beyond the track of the storm's center.

Background

Infrared Satellite

Infrared Satellite

Infrared Satellite

This infrared satellite image shows how cold (and therefore how high) the cloud tops are. Brighter orange and red shadings concentrated near the center of circulation signify a healthy tropical cyclone.

Background

Visible Satellite

Visible Satellite

Visible Satellite (only during daylight hours)

This visible satellite image helps meteorologists pinpoint the low-level circulation center during daylight hours. In cases of strong wind shear (stronger winds aloft than near the surface, sometimes from different directions), one can spot an exposed circulation center, with convection blown downstream. This is an indication of a weakening tropical cyclone.
Check back with us at weather.com and The Weather Channel for the latest updates on this potential Fourth of July holiday week storm.
(MORE: Expert Analysis | WeatherREADY hurricane safety | Hurricane Central)

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One of the Expedition 33 crew members aboard the International Space Station took this photo of Hurricane Sandy at 16:55:32 GMT on Oct. 29, 2012. (NASA)

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