Fred fading; halfway point of hurricane season reached
Hurricane Fred peaked in intensity yesterday afternoon, attaining Category 3 strength with 120 mph winds. It is quite unusual to have such a powerful system so far east in the Atlantic, and Fred is only the third major hurricane to exist east of 35W. Fred is also the strongest hurricane so far south and east in the data record. However, this type of system would have been difficult to document before satellite pictures began in the 1960s.
Fred's glory is past, and the storm is on a downslide now, thanks to moderate wind shear of 15 - 20 knots and dry air eating into the hurricane's southwest side. The shear and the dry air will increase over the next few days, with the shear rising above 40 knots by Monday morning. Sea surface temperatures (SSTs) will also cool to near the 26.5°C threshold needed to sustain a tropical cyclone. The combination of high shear, dry air, and cool SSTs will likely kill Fred by Tuesday.
Figure 1. Hurricane Fred at peak strength, 8:55am EDT UTC 9/9/09. At the time, Fred was a Category 3 hurricane with 120 mph winds. Image credit: NASA.
Elsewhere in the tropics
An upper-level low pressure system has moved over Texas and is expected to spawn a surface low pressure system along the Texas Gulf of Mexico coast on Friday. This low will probably have characteristics of both a tropical and extratropical storm. The surface low is likely to move northeastward and move ashore near the Texas/Louisiana border region on Saturday or Sunday. There will be some high wind shear to the west of the low (shear is currently a high 25 knots), so it is uncertain whether this low will be capable of developing into a tropical cyclone. Regardless, this storm will bring heavy rain capable of causing flooding--and help alleviate the exceptional drought conditions over Southeast Texas.
Early next week, we should be alert for tropical storm development over the waters between the Bahamas and North Carolina, along an old frontal zone. None of the reliable models are forecasting tropical storm development in this area or in the Gulf of Mexico, though.
Figure 2. The climatological halfway point of the Atlantic hurricane season is today, September 10.
Halfway point of hurricane season
September 10 marks the halfway point of the Atlantic hurricane season. Despite a late start (Tropical Storm Ana did not form until August 15, the latest start to a hurricane season since 1992), our number of storms has been near average. An average Atlantic hurricane season has 5 named storms, 3 hurricanes, and 1 intense hurricane by the midpoint of the season. So far this year, we've had 6 named storms, 2 hurricanes, and 2 intense hurricanes. A better measure of hurricane activity that takes into account their destructive power is the Accumulated Cyclone Energy (ACE) index. ACE for an individual storm is computed by squaring the maximum sustained winds of the storm at each 6-hourly advisory, and summing up over the entire lifetime of the storm. As of 5am EDT this morning, the seasonal ACE tally was 37.5. This number should rise to around 40 by the end of the day, thanks to the presence of Hurricane Fred. Over the period 1950 - 2005, the average ACE index for a half-season was 51, so 2009 ranks about 20% below average for the halfway point of the season. But when compared to the hurricane seasons we've been having since the current active hurricane period began in 1995, this year has been quite inactive. Between 1995 and 2008, the average ACE index for the halfway point of the season was 72. Thus, 2009 is about 45% less active than what we've been accustomed to over the past 14 years.
We've been lucky this year that the steering currents have aligned to keep our two major hurricanes, Bill and Fred, out to sea. What will the rest of the season have in store for us? I'll present an analysis on Friday.
Twenty years ago on this date
On September 10, 1989, the strong tropical wave that had moved off the coast of Africa the previous day acquired an organized circulation at the surface and began building a concentrated area of heavy thunderstorms near its center. A new tropical depression, the 12th of the season, was born. Moving westward at 20 mph, the depression brought strong, gusty winds and heavy rain showers to the Cape Verdes Islands as it passed to the south. Forecasters at the National Hurricane Center predicted that the steadily organizing tropical depression would strengthen into a tropical storm within the next day or two. The next name on the list of Atlantic tropical storm names for 1989: Hugo.
Figure 3. AVHRR visible satellite image of Tropical Depression Twelve taken on September 10, 1989. Image credit: Google Earth rendition of the NOAA HURSAT data base.
Jeff Masters
Reader Comments
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Yeah, not much info for the first year it was used. Now, the second in 2005, the name is funny but not the fatalities. :( Hope, I didn't offend anyone. They really need to change there naming system but the names probably mean something totally different to them.
Nope, guess again, somewhere in the Dust Bowl.... Drum Roll please.... (I hate the dustbowl)
UTAH!!!! The site for the most boring weather on earth, and I am a severe weather enthusiast! Figures that I love severe weather and I just hate how thunderstorms come in, hit the rockies and
A. The low pressure system breaks apart and so does the thunderstorm
B. Just before hitting, the thunderstorm dissapates
C.The Salt Lake Splits the thudnerstorm in to halves, and the cirrus trails are the 'only thing that hits us.
Other things like, the other month, A cold front with rotation came 9in at almost the right time. And guess what was missing? MOISTURE!!! And what happened after the cold front passed??? MOSITURE CAME!! And raced the Cold front over Oklahoma!
I made fun of more names then you could possibly imagine.
Blackout is over and im off to bed xD
goodnight
MARINE WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
200 AM EDT FRI SEP 11 2009
MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN SEA
AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W.
WEAK PRES PATTERN ACROSS THE GULF OF MEXICO WITH A 1011 MB
SURFACE LOW JUST S OF BROWNSVILLE TEXAS. THE LOW IS FORECAST
TO MOVE TO THE NNE. SLY WINDS PICK UP ACROSS THE NORTHERN GULF
OVER THE WEEKEND AS A WEAK COLD FRONT APPROACHES THE TEXAS COAST
THE FRONT WILL MOVE OFFSHORE INTO THE NW GULF ON MON AND
EXTEND FROM SE LOUISIANA TO S TEXAS ON TUE.
So if there is actually a surface low there already then. Maye we'll have something to track instead of guess if it will exist. Lol.
A. I am definetly going to find a Japanese Translation Site for making fun of Typhoon Names Accuratly
B. I am going to link my "Dust Bowl Complaints
C. I am Going to Stop capitalizing words so Often starting NOW|
D. I will not stop talking about Thunderstorms and Tornadoes like they are people...... hi Fred!
E. I am going to stop writing at 12:40 a.m. in the morning whrn I have to get up at 9! Probably 11p.m.
F. I am going to stop BROADCASTING MY THOUGHT ON THE BLOG COMMENT SECTION!!
And thats my pledge to stop "comment warming".
By the way, wind shear is hurting ALL cyclones bad, we have only had 2 Hurricanes out of 7 cyclones! One was a depression.
I am more interested in Tornadoes... Oklahoma or Missouri perhaps? Im only 12.... family dependant for moving. Good family, bad location.
She must have forgot because she mentioned you and a few others. She stated they all lived near my area. Oh well, I like Utah. My brother lived in Provo for a while. If it is any constellation, you can come to our area for a visit during our next bad weather event. I will even leave you the keys to my house. LOL
Oh, goody(feel the sarcasm flowing). This won't help me sleep tonight. :(
I thought I would be that way. But I nodded off again tomorrows models should do better since theres something there finally. I better put the puter down and go to sleep. Before it slides on the floor. Lol. See ya tomorrow. :)
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
200 AM EDT FRI SEP 11 2009
FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...
THE NATIONAL HURRICANE CENTER IS ISSUING ADVISORIES ON HURRICANE
FRED...LOCATED ABOUT 740 MILES WEST OF THE CAPE VERDE ISLANDS.
SHOWER AND THUNDERSTORM ACTIVITY CONTINUES IN ASSOCIATION WITH A
NON-TROPICAL AREA OF LOW PRESSURE LOCATED JUST EAST OF THE
MID-ATLANTIC COAST. DEVELOPMENT INTO A TROPICAL OR SUBTROPICAL
CYCLONE IS NOT EXPECTED DUE TO UNFAVORABLE UPPER-LEVEL WINDS. THERE
IS A LOW CHANCE...LESS THAN 30 PERCENT...OF THIS SYSTEM BECOMING A
TROPICAL OR SUBTROPICAL CYCLONE DURING THE NEXT 48 HOURS. HEAVY
RAIN...GUSTY WINDS...AND MINOR COASTAL FLOODING ARE POSSIBLE ALONG
PORTIONS OF THE MID-ATLANTIC COAST OVER THE NEXT DAY OR SO. FOR
ADDITIONAL INFORMATION...PLEASE REFER TO PRODUCTS ISSUED BY LOCAL
NATIONAL WEATHER SERVICE OFFICES IN THE REGION AND HIGH SEAS
FORECASTS ISSUED BY THE NATIONAL WEATHER SERVICE...UNDER AWIPS
HEADER NFDHSFAT1 AND WMO HEADER FZNT01 KWBC.
A SURFACE TROUGH NEAR THE TEXAS COAST IS INTERACTING WITH A MID- TO
UPPER-LEVEL LOW TO PRODUCE DISORGANIZED SHOWERS AND THUNDERSTORMS
OVER THE NORTHWESTERN GULF OF MEXICO. UPPER-LEVEL WINDS ARE
EXPECTED TO REMAIN UNFAVORABLE FOR DEVELOPMENT OF THIS SYSTEM AS IT
REMAINS NEARLY STATIONARY DURING THE NEXT COUPLE OF DAYS. THERE IS
A LOW CHANCE...LESS THAN 30 PERCENT...OF THIS SYSTEM BECOMING A
TROPICAL CYCLONE DURING THE NEXT 48 HOURS. REGARDLESS OF
DEVELOPMENT...LOCALLY HEAVY RAINFALL IS POSSIBLE ALONG THE GULF
COAST FROM NORTHEASTERN MEXICO TO LOUISIANA OVER THE NEXT DAY OR
TWO.
ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.
$$
FORECASTER BLAKE
NATIONAL WEATHER SERVICE WAKEFIELD VA
429 AM EDT FRI SEP 11 2009
.SYNOPSIS...
STRONG HIGH PRESSURE WILL REMAIN OFF THE NEW ENGLAND COAST
TODAY...AS LOW PRESSURE SLOWLY MOVES NORTHWEST TOWARDS THE
DELMARVA. THE LOW WILL WEAKEN ACROSS THE DELMARVA THROUGH TONIGHT...AS
HIGH PRESSURE MOVES WELL OFF THE CANADIAN MARITIMES. ANOTHER AREA
OF HIGH PRESSURE WILL BUILD IN FROM THE NORTHWEST LATER SATURDAY
INTO SUNDAY.
LATEST WX ANALYSIS DEPICTS DEEPENING SUBTROPICAL LOW JUST OFF THE
DELMARVA PENINSULA. MEANWHILE...~1034 SURFACE HIGH PRESSURE
REMAINS OVER ATLANTIC CANADA/JUST OFF THE EASTERN NEW ENGLAND
COASTLINE....WITH HIGH PRESSURE RIDGING SOUTH INTO THE REGION.
ALOFT...UPPER LEVEL LOW PRESSURE REMAINS OVER THE REGION. KDOX
VAD WIND PROFILE DEPICTING VEERING/INCREASING WIND FLOW WITH HEIGHT
(WIND MAXIMA RIGHT AROUND 5-6KFT) OVER THE EASTERN SHORE INVOF
LOW.
Tropical Update
Can ffed take the low level express all the way to the us as a weaker system?
GFS suggests more continued activity through the next few days at least however. CV season doesnt end till the end of September usually. Later all.
Fred will be weakening and moving out of the picture. I'll be back this afternoon.
"LONG TERM (MONDAY THROUGH THURSDAY)...THE UPPER LOW OVER FAR
NORTHEAST TEXAS MONDAY MORNING WITH A CONSENSUS OF THE GFS AND GEM
MOVING THE SYSTEM SLOWLY EASTWARD THROUGH THURSDAY TO GENERALLY OVER
THE LOWER MISSISSIPPI RIVER VALLEY. WILL HAVE TO SEE IF THIS
UNUSUAL PATTERN PANS OUT...BUT IF SO THEN THE ASSOCIATED SURFACE LOW
LIKEWISE DRIFTS EASTWARD KEEPING THE FORECAST AREA IN A WET PATTERN
THROUGH THE EXTENDED PERIOD. WITH FAIRLY GOOD AGREEMENT AMONG THE
GFS AND GEM...AM GOING TO GO WITH LIKELY POPS FOR MONDAY TAPERING TO
GOOD CHANCE FOR TUESDAY. WILL STAY WITH CHANCE POPS FOR WEDNESDAY
THROUGH THURSDAY OUT OF CONSIDERATION FOR UNCERTAINTY WITH THIS
PATTERN. TEMPERATURES WILL BE MODERATED SOMEWHAT BY INCREASED
CLOUDS AND CONVECTION THROUGH MUCH OF THE PERIOD."
FRIDAY 6 AM
HERE IS TODAYS WEATHER QUIZ QUESTION FOR EVERYONE IN THE NATION THAT WATCHES THE WEATHER.
HOW DOES A "NON TROPICAL LOW" MOVE NORTHWEST INTO A SITE AND CAUSE THE ISSUANCE OF TORNADO WATCHES NORTHWEST OF THE CENTER?
The answer.. it doesnt.. the storm is tropical, and that is why tornadoes can develop in the banding.
Think about what you are asked to believe here by the "naming authorities" That tornadoes are possible in spiral bands in a system that is not tropical..to the northwest of its center ( now near the mouth of Delaware bay) How does anyone explain this with a straight face and say its not tropical is beyond me.
This is the first tropical cyclone since 1903 to hit new Jersey directly from the ocean. . The center will crawl inland today and start to die. The worst of the storm appears to be in coastal south Jersey ( I have not spoken to my spies there yet) where winds have been gusting over 50 mph with the torrential rains. I have not seen storm reports on other gusts yet. Highest sustained winds have been 40 kts on Delaware bay. I suspect we will find some reports of wind gusts to near hurricane force with storm reporters check in given the alignment of the bands and their intensity.
By the way,. the temp near the center, at the Delaware May buoy, rose 5 degrees as the center approached
thanks for reading, ciao for now ****
FRIDAY 3 AM
PEAK WIND GUST
At 1 am The Atlantic City Marina had a wind gust to 56 mph, the highest I have seen so far with this storm, and the highest reported the hurricane season from any of the systems to affect the US mainland
ciao for now *****
Im not talking about CONUS threats. And Fred is weakening at a good clip, so its doubtful it will interfere with any other developments.
CV season is 1 August and 30 September. It's not correlated to US landfall but one of the latest CV landfalls was Georges which struck both the islands and conus after September 15.
Has been persistent with this solution and trending a bit stronger...
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