Mighty North Atlantic low bombs to 930 mb
In the Northern Atlantic south of Iceland, an extratropical storm that brought up to 6" of snow to Maryland on Thursday has put on a remarkable burst of rapid intensification over the past 24 hours, with the center pressure dropping 58 mb in 24 hours. The Free University of Berlin, which names all major high and low pressure systems that affect Europe, has named the storm "Jolle." This meteorological "bomb" was analyzed with a central pressure of 988 mb at 12Z (7 am EST) Friday morning by NOAA's Ocean Prediction Center, and hit 930 mb by 7 am EST Saturday morning. The storm may deepen a few more millibars today, but it is close to maximum intensity. A 930 mb central pressure is what one commonly sees in Category 4 hurricanes, and is one of the lowest pressures attained by an Atlantic extratropical storm in recent decades. Since extratropical storms do not form eyewalls, the winds of the massive Atlantic low are predicted to peak at 90 mph (Category 1 hurricane strength), with significant wave heights reaching 52 feet (16 meters.) The powerful storm brought sustained winds of 52 mph, gusting to 72 mph, to Vestmannaeyjar, Iceland at 6 pm local time Saturday. Fortunately, the storm is expected to weaken dramatically before Jolle's core hurricane-force winds affect any land areas.
Figure 1. Winter Storm Jolle, as seen at 10 am EST January 26, 2013. Three hours prior to this image, Jolle was analyzed with a central pressure of 930 mb--one of the lowest pressures in recent decades for an Atlantic extratropical storm. Image credit: Navy Research Lab, Monterey.
According to wunderground's weather historian Christopher C. Burt's post on Super Extratropical Storms, the all-time record lowest pressure for a North Atlantic extratropical storm is 913 mb, set on January 11, 1993, near Scotland's Shetland Islands. The mighty 1993 storm broke apart the super oil tanker Braer on a rocky shoal in the Shetland Islands, causing a massive oil spill.
Other notable Atlantic extratropical storms, as catalogued by British weather historian, Stephen Burt:
920.2 mb (27.17”) measured by the ship Uyir while she sailed southeast of Greenland on December 15, 1986. The British Met. Office calculated that the central pressure of the storm, which was centered some distance southeast of the ship, was 916 mb (27.05”).
921.1 mb (27.20”) on Feb. 5, 1870 measured by the ship Neier at 49°N 26°W (another ship in the area measured 925.5 mb)
924 mb (27.28”) on Feb. 4, 1824 at Reykjavik, Iceland (the lowest on land measured pressure in the North Atlantic)
925.5 mb (27.33”) on Dec. 4, 1929 by the SS Westpool somewhere in the Atlantic (exact location unknown)
925.6 mb (27.33”) on Jan. 26, 1884 at Ochtertyre, Perthshire, U.K. (the lowest pressure recorded on land in the U.K.)
For comparison’s sake, the lowest pressure measured on land during an extra-tropical storm in the United States (aside from Alaska) was 952 mb 28.10” at Bridgehampton, New York (Long Island) on March 1 during, the Great Billy Sunday Snowstorm.
Figure 2. Infrared satellite image of the North Atlantic Storm of January 11, 1993 at 0600Z when it deepened into the strongest extra-tropical cyclone ever observed on earth, with a central pressure of 913 mb (26.96”). Satellite image from EUMETSAT Meteosat-4.
Links
You can see a nice AVHRR image of the east side of the storm at the University of Bern. The raw MODIS pass is here.
The Meteorological Institute of Norway has a nice satellite animation of Jolle.
Wunderground's weather historian Christopher C. Burt's posts on Super Extratropical Storms and World and U.S. Lowest Barometric Pressure Records
Claudio Cassardo's January 23, 2013 post, Very low minima of extratropical cyclones in North Atlantic
Read my story of what it was like to fly though a 936 mb Atlantic low pressure system on January 4, 1989.
Intense winter storms are expected to increase in number due to climate change
In my 2010 blog post, The future of intense winter storms, I discuss how evidence for an observed increase in intense wintertime cyclones in the North Atlantic is uncertain. In particular, intense Nor'easters affecting the Northeast U.S. showed no increase in number over the latter part of the 20th century. This analysis is supported by the fact that wintertime wave heights recorded since the mid-1970s by the three buoys along the central U.S. Atlantic coast have shown little change (Komar and Allan, 2007a,b, 2008). However, even though Nor'easters have not been getting stronger, they have been dropping more precipitation, in the form of both rain and snow. Several studies (Geng and Sugi, 2001, and Paciorek et al., 2002) found an increase in intense winter storms over both the North Atlantic, but Benestad and Chen (2006) found no trend in the western parts of the North Atlantic, and Gulev et al. (2001) found a small small decrease of intense winter storms in the Atlantic.
The U.S. Global Change Research Program (USGCRP), a scientific advisory board created by the President and Congress, concluded this in their 2009 U.S. Climate Impacts Report: "Cold-season storm tracks are shifting northward and the strongest storms are likely to become stronger and more frequent". The USGRP concluded that an increase of between four and twelve intense wintertime extratropical storms per year could be expected over the Northern Hemisphere by 2100, depending upon the amount of greenhouse gases put into the air (Figure 3). If we assume that the current climate is producing the same number of intense winter storms as it did over the period 1961-2000--about 53--this represents an increase of between 8% and 23% in intense wintertime extratropical storms. Two studies--Pinto et al. (2007) and Bengtsson et al. 2006--suggest that the more intense winter cyclones will affect only certain preferred regions, namely northwestern Europe and Alaska's Aleutian Islands. At least three other studies also find that northwestern Europe--including the British Isles, the Netherlands, northern France, northern Germany, Denmark and Norway--can expect a significant increase in intense wintertime cyclones in a future warmer world (Lionello et al., 2008; Leckebusch and Ulbrich 2004; and Leckebusch et al., 2006). None of these studies showed a significant increase in the number of intense Nor'easters affecting the Northeast U.S.
Figure 3. The projected change in intense wintertime extratropical storms with central pressures < 970 mb for the Northern Hemisphere under various emission scenarios. Storms counted occur poleward of 30°N during the 120-day season beginning November 15. A future with relatively low emissions of greenhouse gases (B1 scenario, blue line) is expected to result in an additional four intense extratropical storms per year, while up to twelve additional intense storms per year can be expected in a future with high emissions (red and black lines). Humanity is currently on a high emissions track. Figure was adapted from Lambert and Fyfe (2006), and was taken from Weather and Climate Extremes in a Changing Climate, a 2009 report from the the U.S. Global Change Research Program (USGCRP). The USGRP began as a presidential initiative in 1989 and was mandated by Congress in the Global Change Research Act of 1990, which called for "a comprehensive and integrated United States research program which will assist the Nation and the world to understand, assess, predict, and respond to human-induced and natural processes of global change".
Jeff Masters
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24F and a forecast for snow today thru Wednesday! We will be getting on the slopes in about 2 hours or our 1st day of skiing! I'm like a little kid about to go to Disney I'm so excited!
for destructive winds, damaging winds, heavy rain, abnormally high tides and damaging surf
for people in the Metropolitan, Northern Rivers, Mid North Coast, Hunter, Northern Tablelands, Illawarra, South Coast and Central Tablelands forecast districts
Issued at 12:47 am EDT on Tuesday 29 January 2013.
WIDESPREAD HEAVY RAIN, DAMAGING AND LOCALLY DESTRUCTIVE WINDS, AND DAMAGING SURF FOR EASTERN NSW
Weather Situation
At midnight, ex-Tropical Cyclone Oswald was located over the North West Slopes and Plains of NSW to the east of Narrabri. The system will track steadily southwards to reach the Sydney Metropolitan and Illawarra coastal areas around dawn on Tuesday morning before moving out to sea during the day.
Heavy rainfalls, which may lead to flash flooding are forecast with rain and thunderstorms for the Metropolitan, Mid North Coast, Hunter and Central Coast, Illawarra and South Coast forecast districts and parts of the Central Tablelands forecast districts. Rain, although still falling, has eased in the Northern Rivers and Northern Tablelands, and the risk of heavy rainfall leading to flash flooding will contract southwards during the morning.
Damaging winds with peak gusts over 100 km/h are forecast for coastal parts of the Northern Rivers and southern parts of the Northern Tablelands forecast, expected to ease by dawn. Damaging winds with peak gusts over 100 km/h are forecast for parts of the Metropolitan, Hunter, Mid North Coast and Central Tablelands forecast districts this morning with locally destructive wind gusts in excess of 125km/h possible in exposed coastal areas.
Abnormally high tides which may cause sea water flooding of low lying areas and very heavy surf which may lead to localised damage and coastal erosion are forecast for the Northern Rivers, Mid North Coast, Hunter, Central Coast, Sydney Metropolitan and Illawarra on Tuesday. This may extend to the South Coast later Tuesday. Beach conditions in these areas will be dangerous and people should stay well away from the surf and surf exposed areas.
Rainfalls since 9am Monday include 325mm at Couchy Creek, 237mm at Bellingen, 147mm at Gosford, 111mm at Port Macquarie and 101mm at Coffs Harbour.
The highest wind gust recorded has been 132 km/h (71 knots) at Cape Byron at 4:53 pm Monday afternoon.
Flood warnings have been issued for several rivers in eastern NSW. Refer to www.bom.gov.au/nsw/warnings/ for the latest flood warning information.
The State Emergency Service advises that people should:
Move vehicles under cover or away from trees.
Secure or put away loose items around your house, yard and balcony.
Keep clear of fallen power lines.
Don't drive, ride or walk through flood water.
Keep clear of creeks and storm drains.
If you are trapped by flash flooding, seek refuge in the highest available place and ring 000 if you need rescue.
For emergency help in floods and storms, ring your local SES Unit on 132 500.
The next warning will be issued by 5:00 am EDT Tuesday.
Wow, my vacation is on Feb 14th, I'll be in Wisconsin for 4 days of heaven! I hope you get some snow while you are there! There is not a better feeling in the world to be skiing down a slope while the snow is falling.
1 KM Visible Satellite for Southern Florida
1 KM Visible Satellite for New Jersey - Pennsylvania
1 KM Visible Satellite for Carolinas
1 KM Visible Satellite for Louisiana
1 KM Visible Satellite for Michigan
Click image for link.
Current Sydney Radar.
Current winds
Goodnight all
1 KM Visible Satellite for Northern Texas
1 KM Visible Satellite for Western Texas
1 KM Visible Satellite for Southern Texas
Tropical Cyclone Disturbance #4
TROPICAL DEPRESSION 11F
0:00 AM FST January 29 2013
===================================
At 12:00 PM UTC, Tropical Depression (998 hPa) located 23.4S 177.7E has 10 minute sustained winds of 25 knots. The depression is reported as moving west southwest at 9 knots. Position good based on hourly GMS infrared imagery and recent ASCAT pass.
Overall organization has improved slightly in the past 24 hours. Deep convection displaced to the south of exposed low level circulation center. Cyclonic circulation extends up to 300 HPA. System lies along a surface trough in a high sheared environment. Upper divergence good just to the east of the system. Sea surface temperature is around 27C. Dvorak analysis based on shear patttern with dense overcast about 65 NM away from the center, yielding DT=2.0, PT=2.0, MET=2.0.
Dvorak Intensity: T2.0/2.0/D0.5/24 HRS
Global models have picked up the system and moves it westward with slight intensification.
National Weather Service Storm Prediction Center Norman OK
1242 am CST Monday Jan 28 2013
Valid 291200z - 301200z
..there is a slight risk of severe thunderstorms from the lower Ohio/middle MS valley
region southwestward into northestern Texas...
...
A highly amplified/progressive upper pattern will affect the U.S.
This period...with a strong trough forecast to exit The Rockies and
shift into the central portion of the country with time.
As the strong/sharp trough advances...a sharpening cold front is
forecast to shift across the plains during the first half of the
period...and then continue eastward overnight. By the end of the
period...this boundary should stretch from lower Michigan southward to the
central Gulf Coast and on into the Gulf of Mexico. It is this front
which will focus a zone of strong/locally severe convection across
parts of the central U.S. -- Particularly during the late afternoon
and evening hours.
..lower Ohio/middle MS valleys southwestward into northestern Texas...
Showers and perhaps a thunderstorm or two should be ongoing at the
start of the period across parts of OK and adjacent North Texas/southern
Kansas...ahead of the sharpening surface front. Convection should
remain generally sub-severe however into the afternoon...as
moistening/weak destabilization of the pre-frontal airmass occurs.
By middle to late afternoon...500 j/kg mixed-layer cape should combine
with increasing ascent with the approach of the upper system to
result in an increase in convective coverage/intensity along/ahead
of the cold front. While storms from roughly the MS valley northeastward
into Illinois should struggle to become truly surface-based thus limiting
severe potential...storms from MO southward will be occurring in a
sufficiently moist boundary layer to permit damaging wind/tornado
potential. With the main surface low to remain well to the
north...minimal low-level veering may limit overall tornado potential.
However...strong speed shear given a rapidly strengthening flow
field with height will support organized storms capable of producing
damaging gusts and likely a few isolated tornadoes.
Threat should continue through the evening and into the overnight
hours...with linear evolution of the convection expected with time.
Damaging wind potential may eventually spread east of the MS River
Valley...though the greatest threat should occur during the evening
within a region extending from the arklatex region northeastward across the
Ozarks.
.Goss.. 01/28/2013
Snow in the evening...then light snow likely after midnight. Snow accumulation of 3 to 11 inches. Lows 20 to 25. Light winds. Chance of snow 80 percent.
Basically we (forecasters) have no idea what to expect.
Also, the dry weather is set to continue in the nation's heartland. There isn't much more time left for significant precipitation to alleviate the drought conditions before the furnace is turned on this spring.
I can really tell you are Home now..... Welcome Back
Just musing :)
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