Your Florida Fourth of July Forecast

For folks in Tallahassee, it looks to be a good weather day for celebrating our Independence Day.

At the surface, a “cold” front will help dry things out today in the across the panhandle and Big Bend. In fact, the dewpoint in Tally (as of noon EDT) was 59F! It’s usually in the low 70s this time of year. This pattern is expected to stick around today and should be a nice day and evening for fireworks. Highs will likely be in the lower 90s with a few spots hitting the mid 90s.

I wish I could say the same thing for the peninsula, but people there are in the opposite end of the cold front. Rain chances remain elevated. The HRRR model runs are hinting at showers and thunderstorms developing across the peninsula through the day. In fact, the current Tampa Bay radar (below) shows scattered showers and storms already developing and moving northeast.

KTBW-WDTR1.201407041702

Keep an eye to the sky today and tonight! If you hear thunder, go indoors – you will be close enough to get hit by lightning. Highs in the peninsula will likely be in the upper 80s to lower 90s (depending on how much rain and cloud cover you get).

Amateur Radio Activation for Hurricane Arthur

Bulletin from ARRL:
Arthur, the season’s first Atlantic hurricane, now a Category 1 storm, has prompted the Hurricane Watch Net (HWN) to prepare for activation on July 3. Plans call for net operation to get underway on at 1600 UTC on 14.325 MHz. The National Hurricane Center’s WX4NHC will begin operations for Hurricane Arthur on July 3 at 2200 UTC, also on 14.325 MHz.

See the current net activation plans online:

http://hwn.org/

(HT Jeff Capehart, W4UFL)

Arthur Continues Moving to the North

arthur_2014_07_02_vissat

Tropical Storm Arthur is getting close to hurricane strength (as of the 8 pm EDT advisory) as it begins to pick up speed and move north. Hurricane watches and warnings are in effect for for North Carolina.

Maximum sustained winds are at 70 mph with a minimum central pressure of 990 mb, according to the 8 pm EDT advisory. Arthur is 180 miles south-southeast of Charleston, S.C., or about 305 miles east of Tallahassee.

The tropical storm is looking better organized and symmetrical. Visible satellite imagery from earlier today even started to show what looked like a large eye, but this obviously has not shown up on other modes. It will likely become a hurricane sometime tonight or Thursday.

(Source: NHC/NOAA)

(Source: NHC/NOAA)

Arthur will likely continue it’s northerly trek and may shift to a more north-northeast to northeast path in time. The storm has the potential to either brush or make a direct hit on the Outer Banks (hence the hurricane watches and warnings). Those in who live along the coast in the mid Atlantic need to start enacting their hurricane plans and listen to local officials for updates.

As time moves forward, the impacts to Florida will lessen. There will still be a high threat of rip currents and some wave action on the east coast beaches.

Tropical Storm #Arthur Continues to Improve

Well, this storm has surprised me a bit. The storm formerly known as Invest 91L intensified late last night into the first tropical depression of the 2014 Atlantic hurricane season. This morning, it was upgraded by the National Hurricane Center to tropical storm status.

As of the 8 PM EDT advisory, Arthur was located 90 miles east-southeast of Cape Canaveral, or about 348 miles southeast of Tallahassee.  The TS is nearly stationary and has been moving erratically for most of the day. The pressure has fallen to 1003 mb with maximum sustained winds of 50 mph. A NOAA automated weather station at Settlement Point at Grand Bahama Island reported sustained winds of 47 mph with gusts to 61 mph, according to the latest advisory.

(Source: NHC/NOAA)

(Source: NHC/NOAA)

The structure of the storm has improved during the day. One of the last frames of the visible satellite mode (above) shows better banding to the south and east. There is a better core of cloud cover and it’s looking more symmetrical. It seems to be fighting some of the drier air that has been plaguing the system for the last few days.

Further intensification would not surprise me. In fact, I would not be shocked if we see our first hurricane within the next 24 to 48 hours.

The storm will likely be picked up by a trough that is expected amplify in New England during the next few days, and help move this to the north and east. Also, a ridge to the east out in the open Atlantic could help give it a nudge. Guidance models are in fairly good agreement of moving Arthur to the northeast over time. In fact, the storm should be off of Florida’s shore by sometime Thursday.

The Florida peninsula could see a few rain bands from Arthur, but nothing too crazy. A few of these rain bands could bring  some gusty winds. The east coast could also see some wave action and a high threat of rip currents (swimming is not advised). There is also an isolated threat of tornadoes and waterspouts. A tropical storm watch does remain in effect from Flagler Beach southward to Fort Pierce.

Those in the Carolinas and the mid Atlantic states should keep an eye on the movement and strength of Tropical Storm Arthur as it could have an impact on Independence Day plans.

My next update should be sometime tomorrow (Wednesday).

91L Update: Still Fighting [UPDATED]

UPDATE (10:54 PM EDT): About a couple of minutes after clicking “post”, I found out that the NHC has declared the disturbance the first tropical depression of the season. TD 1 is moving southwest at 2 knots. It has max sustained winds of 30 knots and a minimum central pressure of 1009 mb. I will post more sometime tomorrow (Tuesday).

ORIGINAL POST:

Since this morning’s update, the low off Florida’s east coast had some good signs of development earlier in the afternoon but hasn’t shown much progress. The low is being inhibited by dry air to the north and, therefore, hasn’t become better organized.

The Hurricane Hunters found the lowest pressure of 1009 mb and a max wind of 29 knots (33.4 mph) near 27.68N 78.91W at 4:36 PM EDT. Another recon flight could be sent out again tomorrow (if needed), based on the latest “plan of the day” for tomorrow (Tuesday). 

For most of the day, the invest had thunderstorm development on the southern half of the system. At one point, the system started getting some thunderstorms developing and wrapping around the eastern side. But the development soon went away and it’s now back just to the southern half of the system.

Water vapor imagery (see below) shows drier air on the northern side of the system. As long as this dry air is there aloft, it will have a hard time developing.

(Source: NHC/NOAA)

(Source: NHC/NOAA)

On the synoptic (large) scale, a trough is over the open Atlantic waters and over the upper Midwest (though not as amplified) (see water vapor image with drawing of trough below). Upper air maps show an upper ridge centered over northern Florida and southern Georgia. Winds aloft (at Jacksonville, for instance) are pretty light aloft per the latest sounding. The lack of shear is a good indicator that environmental conditions will likely be favorable for continued development. But now it has to pull a Rocky and fight the dry air to the north of the center.

(Source: NHC/NOAA)

(Source: NHC/NOAA)

In the meantime, the disturbance will likely bring what it has for the last few days across southern and portions of central Florida: Rain. In fact, metro southeast Florida has had reports of flooding. Miami International Airport has received almost two inches of rain today. Additional heavy rain in places where they don’t need it could be a problem in the next few days.

There could be a few strong gusts associated with the disturbance, but it’s nothing to go bonkers over. I believe the greatest threat is the rain.

I’ll post more updates when needed. Keep an eye on my Twitter feed, too.

 

NHC Giving Disturbance 60 Percent Chance of Development

The National Hurricane Center is watching a low off of Florida’s east coast. They are giving it a 60 percent chance of development in the next 48 hours, and a 80 percent chance during the next five days.

(Source: NHC/NOAA)

(Source: NHC/NOAA)

A surface low has been swirling offshore over the weekend, and has helped bring showers and thunderstorms to portions of the peninsula. Based on satellite imagery, most of the  convection is located in the southern half of the low as it seems to be drifting south.

(Source: NHC/NOAA)

(Source: NHC/NOAA)

Wind shear forecasts hint of favorable conditions for intensification in the next 24 to 48 hours. The water temps are above 80. The NHC has indicated that “surface pressures are falling.”

If the thunderstorm activity continues to fire up and wrap around the system, and the pressure continues to fall, there a good chance that this system could become the first tropical depression of the season by midweek.

So far, it will likely keep rain chances elevated across portions of the peninsula in the near future. Guidance models have waffled a tad over the weekend, but most are currently having it sit near or offshore of Florida’s east coast, then take off towards the north and east.  A building ridge well off to the east and a trough to the north might help pick this disturbance off to the north late in the week. We’ll see if things change.

Hurricane Hunters are scheduled to investigate this storm later today, if necessary. I’ll keep an eye on it.

Rain Chances Increase Starting Wednesday

It’s been somewhat dry in Tallahassee for the beginning of the work week, but that will likely change starting Wednesday.

A upper trough is expected to move towards the east and help make the atmosphere a little more unstable. Moisture aloft will also increase.  The surface ridge axis remains to the south, which will bring more of a southwesterly flow.

Rain chances will likely be at 60 percent or better. The SREF ensemble mean has rain chances in Tallahassee around that mark, but higher in other places in the panhandle and peninsula.

With the likely rainfall, temps may not be as high as the last few days (upper 80s to near 90).

High rain chances will likely continue on Thursday and Friday.

NHC: Invest 40 Percent Chance of Development

The National Hurricane Center has given the tropical disturbance in the Bay of Campeche a 40 percent chance of development over the next five days. This has increased since last night’s update.

The low, which is nearly stationary, has not become better organized. Instead, it remains very broad. The NHC reported that gale-force winds were observed (via satellite) to the northeast and east of the center of the low. The strongest convection is on the eastern and southern side of the disturbance (see below).

(Source: NOAA)

(Source: NOAA)

The shear isn’t expected to drop much through the weekend, so immediate development isn’t likely. Guidance has the mid-level ridge over Texas and vicinity moving out near the end of the weekend as a trough digs across the eastern-half of the U.S. If this hangs around for a while, it might be worth watching. But, with the ridge to the north, it may slowly move west. As of now, any impact to Florida appears to be fairly low.

"Spaghetti" plot of guidance models of possible path of the disturbance. (Source: SWFWMD)

“Spaghetti” plot of guidance models of possible path of the disturbance. (Source: SWFWMD)

I’ll still keep an eye on it.