Tropical Storm Arthur – Update 230 pm

There are not any terrestrial warnings for the state of Florida.
Marine and Coastal:
At 230 pm today, the NWS Jacksonville cancelled the tropical storm warning from Flagler Beach to the Altamaha sound from 20 to 60 nautical miles out offshore, as the storm continues to pull away from the Northeast Florida peninsula. There will however, be small craft advisories with heightened seas and swells with occasional winds gusts to gale force (34 knots), particularly in the 40 to 60 nautical mile range through 11 am tomorrow. There may be some rain bands that come during this afternoon and tonight across the coastal waters, that enhance winds intermittently.
smallcraft
hurrevac2july2014
Rips currents and breakers will be dangerous through the fourth of July. This is the biggest impact that we will have to be cognizant of for beachgoers. Remain vigilant for young children near the water, especially at night, when it is hard to discern rip currents.  A few lingering swells will keep an elevated rip current risk at local beaches, potentially through the holiday weekend.  
Winds:  Near the immediate coast, winds will be generally 15 to 20 mph, with higher intermittent gusts at 30 mph associated with a few rain bands that come on shore.
This afternoon will be the closest approach to the northeast Florida and southeast Georgia coastlines.
closestapproach
radar225pm
Rain:  Rainfall will be generally sparse through the next 48 hours. Rainfall amounts may near 1-1.5 inches along the immediate coast, especially south of St. Augustine through Thursday. Some higher amounts may be experiences if a rain band is slow to move or trains over the same location. 
48hourrainfall
High Heat Indices

Dangerous heat indices are expected today and Thursday inland with values near 105 expected during the afternoon across southeast Georgia and northern portions of the Suwanee River Valley.

 
Additional Information Resources:

NWS Jacksonville Webpage:  srh.noaa.gov/jax

NWS Jacksoville Facebook:  facebook.com/US.NationalWeatherService.Jacksonville.gov

NWS Jacksonville Twitter:   twitter.com/NWSJacksonville

AHPS River Forecasts:  water.weather.gov/ahps2/index.php?wfo=jax

Factors Not Yet In Place For Significant Strengthening of Arthur

Tropical Storm Arthur has become a little better organized this evening, with maximum sustained winds of 50 mph. The storm is only drifting west or northwest at less than 5 mph.

The radar image below suggests why Arthur is struggling to intensify.  The surface low pressure center (small L on image) is displaced a considerable distance NW of low pressure further aloft (large L). Much of the thunderstorm activity is circulating around the low aloft.  Because the low aloft is not directly above the surface low, there is weak northerly shear over the surface low, along with drier air spreading in from the north.

ArthurRadar

The latest model guidance keep the low aloft separated from the surface low, and thus show minimal intensification of the system over the next few days. However, once Arthur gets east of the South Carolina coast, the surface  low becomes positioned beneath the low aloft, and strengthening is shown…possibly to a hurricane as it approaches the North Carolina coast.

That is the current expectation.  If, however, the surface low becomes positioned under the low aloft sooner, and the system is over the warm gulf stream, intensification could occur sooner than forecast and we could see a stronger system well offshore of GA than currently expected.  This would only impact winds and seas over the marine waters.

At this time…little has changed with respect to expected impacts of Arthur, which should be fairly minimal for areas of northeast FL/southeast GA that are well inland from the coast.  We may see some rain bands from Arthur affect the coastal counties Wed as Arthur moves northward…bringing heavy downpours and gusty winds of 25 to 35 mph.   The greatest threat from Arthur will be strong rip currents through July 4th.

Continue to closely monitor the progress of Arthur, and your latest forecast.

Additional Information Resources:
NWS Jacksonville Webpage: srh.noaa.gov/jax
NWS Jacksonville Facebook: facebook.com/US.NationalWeatherService.Jacksonville.gov
NWS Jacksonville Twitter: twitter.com/NWSJacksonville
AHPS River Forecasts: water.weather.gov/ahps2/index.php?wfo=jax

 

…Tropical Storm Arthur Offshore of the Central Florida Atlantic Coast…

At 2:00 p.m. EDT, Tropical Storm (TS) Arthur was located near latitude 27.9 north and longitude 79.4 west, or approximately 210 miles south-southeast of Mayport, Florida. This position is also about 150 miles southeast of Flagler Beach, Florida. TS Arthur is moving northwest at 5 mph. This general motion should continue through tonight, followed by a turn toward the north on Wednesday. The center of the tropical cyclone is expected to remain offshore and move east of the central Florida east coast during the next day or so. The system is forecast to pass 80 to 120 miles offshore of northeastern Florida on Wednesday and Wednesday night and about 120 to 140 miles east of southeast Georgia coast early Thursday morning. Tropical storm force winds extend outward up to 45 miles from the center. Conditions should allow for at least steady strengthening and TS Arthur is expected to become a hurricane offshore or near the Carolina Coasts by Thursday night and Friday morning.

 

 

hurrevac1july2014

 

Local Impacts & Timing:

Based on the latest forecast, the greatest impact from this system will likely be over the adjacent Atlantic waters out 20 to 60 nautical miles Wednesday and Wednesday night, with conditions improving Thursday as the low tracks farther NE away from the region. A tropical storm watch was issued this morning for the offshore Atlantic coastal waters (20-60 NM east of the Altamaha River southward to 20-60 NM east of Flagler Beach) and this watch may be upgraded to a warning around 430 p.m. A Watch means that Tropical Storm conditions are possible over these waters within 48 hours.

The highlight impact (rip currents) for our region

As onshore winds increase through midweek and swells build, the chance of dangerous rip currents along the coast will also increase. Today there is a moderate risk of rip currents, with a high risk of rip currents expected on Wednesday. Breezy ENE winds will near 15-25 mph today and Wednesday with higher gusts…especially along the immediate beaches. The main impact for coastal counties will be dangerous rip currents on area beaches from swells originating from the storm through July 4.  This is where lifeguards and local coastal county officials will have to remain vigilant and safeguard beach goers into the holiday weekend.  Folks going to nighttime fireworks near the beach, a word of caution, please be very mindful of whereabouts of children, due to the strong rip currents that will be hard to discern during the dark of night!   

Marine Impacts:

As Tropical Storm Arthur begins to track northward alongside the northeast Florida and Southeast Georgia Atlantic Coast tonight through Wednesday Night, the threat for sustained winds offshore is likely to increase.  The latest forecast is for tropical storm force winds from late Wednesday afternoon to late Wednesday evening.

Northeast winds will likely increase to Tropical Storm strength Wednesday and Wednesday night over the offshore waters (20-60 NM offshore). Winds will increase 30 to 35 knots over the offshore waters with gusts up to 50 knots possible Wed through Wed night.  Seas will build up to 7 to 10 feet offshore by Wednesday night. Mariners are encouraged to continue to closely monitor this system.

Event Rainfall: 

These are general rainfall totals, remember rainfall totals may be locally higher if a rain band stalls over a particular area.

rainfallafternoontotals

Winds:  

Generally during the event, winds will be generally be between 10 to 20 mph during the entire event for all inland areas.  The exception will be for occasional squalls with the outer rain bands furnishing wind gusts to 30 mph along the immediate beaches and intracoastal waterway.   

Additional Information Resources:
NWS Jacksonville Webpage: srh.noaa.gov/jax
NWS Jacksonville Facebook: facebook.com/US.NationalWeatherService.Jacksonville.gov
NWS Jacksonville Twitter: twitter.com/NWSJacksonville
AHPS River Forecasts: water.weather.gov/ahps2/index.php?wfo=jax

 

Tropical Depression 1 – Local NE FL and SE GA Impacts Tonight thru Early Thursday

…Marine & Coastal Impacts likely Wednesday and Wednesday Night from Tropical Depression One…
…Depression One likely to become a Tropical Storm later Today…

 

Synopsis & Forecast Confidence: 

Tropical Depression One was about 170 miles SE of Flagler Beach early this morning. Conditions are favorable for this depression to develop into a Tropical Storm later today and then track north and northeast offshore the northeast Florida and southeast Georgia coast Wednesday night.  Forecast models have come into good agreement with this storm strengthening to Tropical Storm strength as it moves northward while paralleling the southeast Atlantic coast through late Thursday.
tropical_despression_1_resized
Local Impacts & Timing:
Based on the latest forecast, the greatest impact from this system will likely be over the adjacent Atlantic waters and along the immediate coastline Wednesday and Wednesday night, with conditions improving Thursday as the low tracks farther NE away from the region. A tropical storm watch was issued this morning for the offshore Atlantic coastal waters (20-60 NM east of the Altamaha River southward to 20-60 NM east of Flagler Beach). This watch means that Tropical Storm conditions are possible over these waters within 48 hours.
tropical_storm_watch_resized
Marine Impacts:
NE winds will likely increase to Tropical Storm strength Wednesday and Wednesday night over the offshore waters (20-60 NM offshore). Winds will increase up to 35 knots offshore with gusts up to 50 knots possible Wed through Wed night.  Seas will build up to 7 to 9 feet offshore. Mariners are encouraged to continue to closely monitor this system. 

Coastal Impacts:
As onshore winds increase through midweek and swells build, the chance of dangerous rip currents along the coast will also increase. Today there is a moderate risk of rip currents, with a high risk of rip currents expected on Wednesday. Breezy ENE winds will near 15-20 mph today and Wednesday with higher gusts. 

Thunderstorm/Rainfall Outlook:

Coast: Scattered showers and thunderstorms are expected to begin to move onshore later today, edging their way northward up the Atlantic coast tonight through late Wednesday. Bands of showers and isolated thunderstorms will move onshore through Wednesday night, with locally heavy rainfall possible. Rainfall amounts of 1 to 2 inches are possible generally south of St Augusine thorugh Thursday, with locally higher amounts. Gusty winds in squalls may reach up to 40 mph.

Inland:  Scattered mainly afternoon and evening thunderstorms are expected both today and Wednesday.

today_wed_forecast_resized
Once again, this forecast is highly dependent on the eventual track and strength of this Tropical system.

Additional Information Resources
NWS Jacksonville Webpage: www.srh.noaa.gov/jax
NWS Jacksoville Facebook: facebook.com/US.NationalWeatherService.Jacksonville.gov
NWS Jacksonville Twitter:  twitter.com/NWSJacksonville
AHPS River Forecasts: water.weather.gov/ahps2/index.php?wfo=jax