Another very dry high pressure system

Across most of the Northeast and Mid-Atlantic, dewpoints have fallen all the way into the 40s and this is the second time we’ve seen a similar cool August air mass. This strong, dry high pressure system should help to suppress a lot of Fay’s leftover moisture and clouds further South and West. It is getting very dry out there with many spots coming in at less than inch of precip for the month. We’ll have more on that later in the week.

What a crazy storm!

Fay is dying out and it certainly turned into a unique storm. However, the whole “it made landfall four times” angle is a bit ridiculous and of course the media is having a field day. Yes, the ‘center’ point of the storm did officially hit land after coming off the water four seperate times. But, the actual circulation and impact of the storm really never left. What was remarkable was how it maintained tropical storm status over land for about 3-4 days. This is very rare and a couple reasons why were likely that it remained close to its energy source in the water (and part of the circulation was over the Gulf or Atlantic) and the topography of Florida. Fay actually strengthened in Southern Florida as it developed an eye-like feature. The reason was that it was sitting over the Everglades and the swampy, muddy area helped evapotranspiration and other things that a tropical system likes. Rainfall amounts were highest in the Melbourne area with an asounding two feet in spots. 

Tropical Storm Fay Update

TS Fay is moving along at a snail’s pace near the Eastern Florida coast early this afternoon. With weak steering currents in place, and a strong area of high pressure to the north, Fay has not moved much the last few days. This has resulted in some astronomical rainfall totals especially along the Central Florida coast. Due to the banding of Fay, there are significant differences from place to place. The highest total I could find was at Windover Farms in Melbourne, where 26.20 inches of rain has fallen. Even the US Air Force recorded 20.03″ at Cape Canaveral. There are plenty of totals that are between 10 and 20 inches. This has made inland freshwater flooding the primary concern of local officials across the area. The worst part is that additional rainfall is occurring, and will continue through Friday causing additional flooding concerns. Below is the radar estimated rainfall since Fay moved ashore. Note the pink colors where over 14 inches of rain fell in the Melbourne/Cape Canaveral area. 

Melbourne, FL Radar Estimated Rainfall

Weather Updates

First, we’ll briefly talk about TS Fay today. After holding her own yesterday even while inland, Fay weakened considerably in the last 12-18 hours, and while some brief restrengthening is possible should Fay emerge off the GA/FL Coast, the chances of Fay becoming a hurricane at this point are rather remote. Strong high pressure to the north of Fay will keep her associated moisture in the vicinity of the SE US & Gulf Coasts for days to come.

Closer to home, the mid-Atlantic and Northeast had an unusually strong cold front (for August) pass through yesterday afternoon & evening. This has brought cool temperatures to the area, with very low dewpoints. Some places north of Central NJ may not see highs get back into the 80’s until this weekend! Be sure to enjoy this weather!

Tropical Storm Fay Update

Well, since yesterday’s post, Fay has made 2 landfalls. The first was yesterday afternoon at Key West, and the other was at Cape Romano on the southwest coast of Florida. As of late morning, Fay is near Lake Okeechobee, still with winds of 60 MPH, and will only slowly move towards the north and north-northeast. This will keep showers in the forecast for the Florida peninsula for the next couple of days, bringing about the potential for flooding. Numerous locations have already had a few inches of rain, with more on the way.

Where Fay goes from here remains very much in doubt.  A huge area of high pressure is in place to the north which will prevent Fay from moving too far north.  Latest computer guidance suggests that Fay will slowly move towards the NE coast of Florida over the next day or two, slow down considerably and then begin to move back towards the northwest. There is a decent possibility that Fay may end up in the Atlantic Ocean off the FL/GA coast and intensify before moving back ashore later this week.

NHC TS Fay Forecast Track

Tropical Storm Fay

After a quiet period in the tropics, Tropical Storm Fay has formed in the Caribbean. Currently the storm is over the waters between Cuba & Florida. But outer rain bands are currently impacting the southern third of Florida, and extend as far eastward the Bahamas. The storm is not very symmetrical, and the bulk of the heavier showers and thunderstorms are to the east of the center of the storm. This will keep showery weather in Florida for a while, even before the storm begins to make a landfall somewhere on the west coast of Florida. If the storm remains over water long enough, there is a decent chance that Fay will strengthen into a Category 1 Hurricane prior to landfall.

After landfall,  Fay will slow down considerably due to the presence of a strong ridge of high pressure that will block its path. This will keep a fair amount of moisture in the southeast US at least into the Mid-week time frame, keeping the threat for tropical downpours a very real possibility even after the storm weakens.

Another Busy Weather Day Ahead

Yesterday’s severe threat was interesting in that it did not appear to be a great day for developing severe thunderstorms. However, there were numerous severe storms with hail being the biggest problem. Instability and some dry air aloft helped to initiate some nasty storms. Early in the evening, a very clear feature showed up on KDIX radar as a cluster of storms helped to combine one distinct outflow boundary thru Central and South NJ as well as SE PA, creating some gusty winds. The image belows shows the boundary with about 10-15 DBZ moving thru the Trenton area. Also, notice the sea breeze boundary across South NJ moving inland. More storms are likely today, though early cloud cover may inhibit some storm development.

Outflow Boundary moving SSE (from KDIX radar)

 

What is this?

It is mid-August and yet the signs of fall, even winter continue. A very anomalous surface low pressure system across the South is now bringing widespread rain to the Carolinas. This low amazingly is forecasted by nearly all models to move to the Northeast close to the coast and develop into a potent coastal low / pseudo-nor’easter. It should stay far enough out to sea to not affect the Mid-Atlantic or Northeast with rain (though showers will threaten from yet another upper-level trough that comes thru).

Unforturnately, it is almost impossible to see what this August pattern means for Winter. The trends could lead to the pattern breaking for a very nice September with a ridge dominating. Or, it could be a sign of things to come into 2009. But there just isn’t enough data or evidence to see what will happen.

Regional Radar 8-13-08

A busy couple of days

In my opinion, the best opportunity to see large hail in the mid-atlantic is when there is a closed upper-low nearby in the summer-time. It is unusual, but it does happen and boy were conditions right on Sunday and Monday. The upper-low typically brings in cold air aloft and a lot of wind shear. When you add in a little instability, large hail can form along with some pretty nasty thunderstorms. We saw several reports of large hail in the two-day period, including golf ball sized hail (2.00″) in Chester County, PA. I was able to see a couple minutes worth of quarter sized hail near Allentown, PA.

Monday brought more storms and this time with the coolest summer air of the season in place, there were a few waterspouts that formed near the Jersey Shore. The picture below is along Barnegat Bay and resembles probably the most impressive waterspouts photographed in a long time. This unusual pattern breaks a bit this week, but temps are still going to be below normal with several isolated precip shots. Certainly, not what one would expect during the “Dog Days” of Summer.

From the Asbury Park Press (Photo courtesy of Donald Launer)

Bridgeport, CT Funnel Cloud & Long Island Waterspouts

After the microburst on the 6th in Harrington Park, NJ, severe weather struck parts of the mid-Atlantic and Northeast once again on the 7th. Particularly hard hit was Connecticut and Long Island.  As mentioned in other posts this week, the area is under a strong upper-level trough. This means that very cold air (for August) is above the region. Given the strong August sunshine heating the ground, this causes a decent degree of instability. Combine that instability with a disturbance moving through the area, and severe storms fired up yesterday. Some of these storms were very slow movers, with numerous flooding warnings issued and roadways flooded out.

A few of the thunderstorms also exhibited signs of rotation. A few funnel clouds and waterspouts were seen across the area. One funnel cloud was seen near Bridgeport, CT, and there were 2 reports of waterspouts on Long Island, one near Lloyd Harbor and the other near Baiting Hollow. There were no indications that these caused and damage. However, there were plenty of large hail and other wind damage reports across the area.  More thunderstorms are expected today (mainly this afternoon) but the intensity should be lower due to less available moisture. Still be on the lookout later on, particularly for hail. That cold air above the surface will make hail a concern.

View of Lloyd Harbor Waterspout from Woodbury, NY (WCBS AM/Kristine Alcala)

Microburst in Harrington Park, NJ

Early yesterday morning (Aug. 6) a line of intense showers and thunderstorms moved through parts of Northern NJ and nearby parts of NY. In the middle of the showers and storms there was a microburst that impacted parts of Harrington Park, NJ. A microburst occurs when strong winds are pushed to the ground in a thunderstorm causing straight line (not tornadic) wind damage.  

After storm surveys by the National Weather Service, winds were estimated to peak around 90 MPH for the relatively small area (0.25 miles long by 200 yards wide) impacted by the microburst. Thankfully, the worst of the damage was limited to 5-10 homes, but nearly 1500 people were without power following the storm.

The Summer of Troughs Continues

It’s been quite the summer for troughs across the mid-Atlantic and Northeast. It looks like another trough is going to setup over the region for the rest of the week into the weekend. As we have discussed in earlier posts, absent other weather features (cold fronts, warm fronts etc.) troughs provide for changeable weather. Usually this means morning sunshine with building clouds for the afternoon, with a few scattered showers or thundershowers in the late afternoon and evening.

In a situation like today when a cold front crossed the area earlier in the day, severe weather is less of a concern than with “air mass” type thunderstorms since instability is less given lower humidity levels. However, hail becomes more likely. This is due to cooler temperatures above the surface. With that all said, we are expecting much of the next few days to be dry. However, scattered showers and thundershowers may develop each afternoon with the presence of the trough so plan outdoor work accordingly. Have a good one!

Mid-Level Chart-Upper Level Low & Trough (Friday AM GFS Forecast)

Severe Storms in Chicago

 

Last night intense clusters of thunderstorms, or Mesoscale Convective Complexes, developed across parts of the Plains and Mid-West states. Scores of Severe Thunderstorm and Tornado Warnings were issued in the area, especially in Illinois. In excess of 255,000 customers lost power in the Chicago area due to the strong winds to hurricane force in localized gusts. But perhaps those most impacted by the storms were those in attendance at last night’s Chicago Cubs-Houston Astros game at Wrigley Field. During the game, a Tornado Warning was issued for Downtown Chicago. Soon thereafter, nearly continuous thunder and lighting and heavy rains arrived at Wrigley. Fans were evacuated into the concourse area of the stadium, though some brave people remained underneath the overhangs. After a delay of 2 hours 45 minutes, play resumed but only for 50 minutes before more severe thunderstorms threatened the area and the game was finally called.

 

Tropical Storm Edouard

TS Edouard

After a relative lull in tropical activity, we’ve got a new Tropical Storm, Edouard in the Gulf of Mexico. Right now, with 45 MPH winds, Edouard is not all that strong but is close to shore as it moves westward towards the Texas Coast. However, over the very warm Gulf waters (water temperatures in the mid 80’s) and light upper-level winds, strengthening is likely. With this in mind, the National Hurricane Center has issued a Hurricane Watch in addition to Tropical storm warnings for the Louisiana and Texas coasts. The biggest impact from this storm will likely be the heavy rain potential in Texas with 3-5 inches likely in many spots, with isolated amounts up to 10 inches possible.