July Atlantic hurricane outlook
It's mid-July, and we have yet to see a named storm form in the Atlantic this month. The computer models are not predicting any development through at least July 20, and if we make it all the way to the end of the month without a named storm forming, it will be the first July since 2009 without a named storm. Since the current active hurricane period began in 1995, 13 of 17 years (76%) have had a named storm form during July. The busiest July occurred in 2005, when five named storms and two major hurricanes formed. These included Hurricane Dennis and Hurricane Emily--the strongest hurricanes ever observed so early in the season. Only eight major hurricanes have formed in July since record keeping began in 1851. As seen in Figure 1, most of the last half of July activity occurs in the Gulf of Mexico and waters off the Southeast U.S. coast. These type of storms form when a cold front moves off the U.S. coast and stalls out, with the old frontal boundary serving as a focal point for development of a tropical disturbance (as happened for Alberto, Beryl, Chris, and Debby in 2012.) There will be at least two cold fronts moving off the U.S. Mid-Atlantic coast over the next two weeks. The first of these fronts will push offshore around July 20, and we will need to watch the waters offshore of North Carolina for development then. Formation potential will be aided by ocean temperatures that are about 0.7°C (1°F) above average along the U.S. East Coast.
Figure 1. Tracks of all tropical storms and hurricanes 1851 - 2006 that formed July 16-31. The U.S. coast from North to Texas are the preferred strike locations. Only a few storms have formed in the tropical Atlantic and Caribbean in July. Wind shear is typically too high and SSTs too cool in July to allow African waves in the Caribbean and tropical Atlantic to develop into tropical storms. However, a few long-track "Cape Verdes" hurricanes have occurred in July, spawned by tropical waves that came off the coast of Africa. African tropical waves serve as the instigators of about 85% of all major hurricanes.
Figure 2. The seasonal distribution of Atlantic hurricane activity shows that July typically has low activity. Image credit: NHC.
Sea Surface Temperatures: slightly above average
The departure of Sea Surface Temperatures (SST) from average over the tropical Atlantic between Africa and Central America was about 0.3°C above average during June (Figure 3.) This figure has not changed much over the first two weeks of July. These temperatures are not warm enough to appreciably affect the odds of a July named storm or hurricane. The strength of the Azores-Bermuda high has been near average over the past two weeks, driving near-average trade winds. The latest 2-week run of the GFS model predicts continued average-strength trade winds through late-July, so SSTs should remain about 0.3°C above average during this period, due to average amounts of cold water mixing up from below due to the wind action on the water.
Figure 3. Sea Surface Temperature (SST) departure from average for July 12, 2012. SSTs were 0.3°C above average over the tropical Atlantic's Main Development region for hurricanes, from Africa to Central America between 10° and 20° North Latitude. Note the large region of above average SSTs along the Equatorial Pacific off the coast of South America, the hallmark of a developing El Niño episode. Image credit: NOAA/NESDIS
El Niño on the way?
For two consecutive weeks, ocean temperatures 0.5 - 0.6°C above average have been present in the tropical Eastern Pacific, which is right at the threshold for a weak El Niño episode. NOAA's Climate Prediction Center has issued an El Niño Watch, and gives a 61% chance that El Niño conditions will be present during the August - September - October peak of the Atlantic hurricane season. The likely development of a full-fledged El Niño episode means that Atlantic hurricane activity will probably be suppressed in 2012, due to the strong upper-level winds and high wind shear these events typically bring to the tropical Atlantic.
Figure 4. Sea Surface Temperature (SST) departure from average for the the equatorial Eastern Pacific (the area 5°N - 5°S, 120°W - 170°W, also called the "Niña 3.4 region"). El Niño conditions exist when the SST in this region rises 0.5°C above average. As of July 9, 2012, SSTs in the Niño 3.4 region had risen to 0.5°C above average. To be considered an "El Niño episode", El Niño conditions must occur for five consecutive months, using 3-month averages. Image credit: NOAA Climate Prediction Center.
Wind shear: above average
Wind shear is usually defined as the difference in wind between 200 mb (roughly 40,000 foot altitude) and 850 mb (roughly 5,000 foot altitude). In most circumstances, wind shear above 20 knots will act to inhibit tropical storm formation. Wind shear below 12 knots is very conducive for tropical storm formation. High wind shear acts to tear a storm apart. The jet stream has two bands of strong high-altitude winds that are currently bringing high wind shear to the Atlantic. The southern branch (subtropical jet stream) is bringing high wind shear to the Caribbean, and the northern branch (polar jet stream) is bringing high wind shear to the waters offshore of New England. This configuration often leaves a "hole" of low shear between the two branches, off the Southeast U.S. coast and over the Gulf of Mexico. The jet stream is forecast to maintain this two-branch pattern over the coming two weeks. Wind shear has been about 10 - 20% higher than average over the first two weeks of July, and is predicted to be mostly above average for the coming two weeks. This will cut down on the odds of a July storm.
Figure 5. Vertical instability over the Caribbean Sea in 2012 (blue line) compared to average (black line.) The instability is plotted in °C, as a difference in temperature from near the surface to the upper atmosphere. Thunderstorms grow much more readily when vertical instability is high. Instability has been lower than average, due to an unusual amount of dry air in the atmosphere, reducing the potential for tropical storm formation. Image credit: NOAA/NESDIS/CIRA.
Dry air: above average
As seen in Figure 5, there has been an unusual amount of dry, stable air in the Caribbean this year creating low levels of vertical instability. This has occurred due to a combination of dry air from Africa, and upper-atmosphere dynamics creating large areas of sinking air that dry as they warm and approach the surface. The Gulf of Mexico and tropical Atlantic between the coast of Africa and the Lesser Antilles have also seen low vertical instability this summer. June and July are the peak months for dry air and dust coming off the coast of Africa, and the Saharan dust storms have been quite active over the past two weeks. Expect dry air to be a major deterrent to any storms that try to form in the tropical Atlantic during July.
Steering currents: average
The predicted steering current pattern for the next two weeks is a typical one for July. We have an active jet stream bringing many troughs of low pressure off the East Coast of the U.S. These troughs are frequent enough and strong enough to recurve any tropical storms or hurricanes that might penetrate north of the Caribbean Sea. Steering current patterns are predictable only about 3 - 5 days in the future, although we can make very general forecasts about the pattern as much as two weeks in advance. There is no telling what might happen during the peak months of August, September, and October--we might be in for a repeat of the favorable 2010 and 2011 steering current pattern, which recurved most storms out to sea--or the unfavorable 2008 pattern, which steered Ike and Gustav into the Gulf of Mexico.
Summary: a below average chance of a July tropical storm
Given that none of the computer models are forecasting tropical storm formation in the coming seven days, SSTs are only slightly above average, and wind shear and vertical stability are above average, I'll go with a 30% chance of a named storm forming in the Atlantic during the remainder of July.
Figure 6. Hurricane Emilia over the Eastern Pacific at 20:35 UTC July 10, 2012. At the time, Emilia was a Category 3 hurricane with 125 mph winds. Emilia peaked earlier in the day as a Category 4 storm with 140 mph winds--the strongest hurricane in the East Pacific so far in 2012. Image credit: NASA.
An active Eastern Pacific hurricane season
It's been a very active start to the Eastern Pacific hurricane season, where we've already had six named storms, four hurricanes, and three intense hurricanes. A typical season has 4 named storms, 2 hurricanes, and 0 intense hurricanes by July 14. The formation of Tropical Storm Fabio on July 12 marks the 4th earliest formation of the Eastern Pacific's season's sixth storm. The record is held by the year 1985, when the season's sixth storm formed on July 2. Record keeping began in 1949.
Have a great weekend, everyone, and I'll be back Monday with a new post.
Jeff Masters
Reader Comments
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It's a community in Orange Co.
4.4 / 980.4mb/ 74.6kt
Final T# Adj T# Raw T#
4.4 4.4 6.0
Estimated radius of max. wind based on IR :N/A km
Center Temp : -23.6C Cloud Region Temp : -70.4C
Scene Type : EYE
Positioning Method : FORECAST INTERPOLATION
Ocean Basin : EAST PACIFIC
Dvorak CI > MSLP Conversion Used : PACIFIC
Tno/CI Rules : Constraint Limits : MW ON
Weakening Flag : OFF
Rapid Dissipation Flag : OFF
no its only climate when we have more record heat than record cold consistently for more than a fluke period.
People on the blog make the mistake you pointed out often, jumping on the record heat as AGW and the record cold as normal, but it doesnt change anything.
Record heat is not climate.
Only overall comparisons can reveal climate changes in the form of more record heat than cold.
This requires extended observation, much longer time than any particular heat wave.
The title of the webinar is, "The Year-Round CAT Season: Is Your Business Prepared for Increasingly Frequent Severe Weather?"
80-90 mph?
got some black clouds like you posted the other day in the distance heading my way
wave should lose characteristics over the next day or two as it moves W across the gulf.
It is mostly dead already
$$MoneyBoy
CME Impact simulation for tomorrow.
Published on Jul 12, 2012 by ve3en1
A major and long duration eruption reaching X1.4 around Sunspot 1520 peaked at 16:52 UTC Thursday afternoon. Type II and IV Sweep Frequency Events were recorded. This event was also responsible for a Strong R3 Radio Blackout on the sunlit side of Earth. A Coronal Mass Ejection was also produced and looks to be Earth directed.
:)
but it's sending me shivers.
A baby is born,
crying out for attention.
Memories fade,
like looking through a fogged mirror
Decision to decisions are made and not bought
But I thought,
this wouldn't hurt a lot.
I guess not.
supposed to miss the east US and hit the west.
Maybe a huricane at next adxisory.
the impact is going to be relatively minor
this time but sooner or later well we wait and see
How do you figure???
The CME launched toward Earth by yesterday's X-flare is moving faster than originally thought. Analysts at the Goddard Space Weather Lab have revised their forecast accordingly, advancing the cloud's expected arrival time to 09:17 UT (5:17 am EDT) on Saturday, July 14th. Weekend auroras are likely.
Doesn't look like it will affect the CONUS at all.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be at mostly quiet to unsettled levels for day one (13
July). Unsettled to active levels, with isolated minor storm
intervals, are expected on days two and three (14 - 15 July) as
effects from the 12 July CME are expected to become geoeffective.
III. Event Probabilities 13 Jul-15 Jul
Class M 80/80/80
Class X 35/35/35
Proton 99/99/50
PCAF red
[Latest and Full Report]
I'm giving at training class this week and yesterday we had water coming in to the room ...wonder what this afternoon has in store of us???
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 194 Issued at 2200Z on 12 Jul 2012
IB. Solar Activity Forecast: Solar activity is expected to be
moderate with a chance for X-class events for the next three days
(13 - 15 July).
Date: 12:00 PM EDT Friday 13 July 2012
Condition: Mainly Sunny
Pressure: 30.15 inches
Tendency: falling
Visibility: 15 miles
Air Quality Health Index: 5
Temperature: 86.2°F
Dewpoint: 64.9°F
Humidity: 49 %
Wind: S 5 mph
Humidex: 97
Max: 81°F
Min: 63°F
thats slower, it was supposed to arrive at 1am edt before, and it was on the map, supposed to be mainly in the pacific, with some in the W US, and about none for the E US before the nightime areas.
but it may have changed, i cant find the map of the noaa space site now.
i hate the redesign
Yes, it was really pounding down earlier. Now it's seems to have slowed at my location. Still raining with distant thunder now. Was a loud night! Been under FF Warning since early. I'm ready to pass this rain on to someone who might need it but...can I keep the temps? :-)
Thunderstorm Rain
72°F
22°C
Humidity100%
Wind SpeedCalm
Barometer30.06 in
Dewpoint72°F (22°C)
Visibility1.75 mi
That's not my wording, it a copy and paste... ;)
Link
Space Weather Message Code: WATA20
Serial Number: 497
Issue Time: 2012 Jul 13 1313 UTC
WATCH: Geomagnetic A-index of 20 or greater predicted
NOAA Scale: Periods reaching the G1 (Minor) Level Likely
Valid for UTC Day: 2012 Jul 14
Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.
Space Weather Message Code: ALTEF3
Serial Number: 1933
Issue Time: 2012 Jul 13 0739 UTC
CONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 1932
Begin Time: 2012 Jul 11 1055 UTC
Yesterday Maximum 2MeV Flux: 2470 pfu
Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.
4 seasons will be cut to 3 due to budget cuts...
i wouldn't bother even communicating, but you don't seem like a troll.. but you're pressing on this for what reason?
Carallon Bell Tower?
-- Dr. Masters
I think he meant to say "North Carolina."
it's how i communicate with that one person....not everyone can communicate the same.....and i can see how ya might take it as baiting or trolling i can respect that, but i got my troll shot in may i am good for 6 months.....
i think you will have a cold winter this year....
Those form when High Cirrus,ice crystals refract the sunlight O believ ..
I shot one here in NOLA a few weeks back as well.
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