[Hurricane Rita.]

This of help?

Tropical Cyclone Position and Intensity Data

Id Name Date Time Lat(10ths) Lon(10ths) Dir of Motion Speed(10ths)

18L RITA 20050921 1800 243N 0862W 270 110

18L RITA 20050921 1200 243N 0853W 275 110

18L RITA 20050921 0600 242N 0840W 280 120

18L RITA 20050921 0000 240N 0827W 275 110

18L RITA 20050920 1800 239N 0817W 275 140

18L RITA 20050920 1200 237N 0803W 279 130

If "Dir of Motion" is degrees on a compass Rita's latest recorded movement is directly west, having previously been more to the north.

[Sst's And Sea Ice - Trends]

Accidental double post. First one timed out but actually was sent through.

[Sst's And Sea Ice - Trends]

Indeed, you'd expect the recent flaring up of the north atlantic to continue to cool.

http://weather.unisys.com/archive/sst/sst_anom_loop.gif

However... with S/N movement of Maria I'm not sure they'll be a big cooling effect in the waters south of Iceland, for this reason - the storm might drag warm water with it. It's like when you add hot water to a cold bath and then drag your hand the length of it. Any cooling we might see in the North Atlantic next week (from colder waters being churned up by Maria) maybe somewhat offset from warm waters bought along from the gulf stream. It might be interesting to see the next image in the loop.

[Sst's And Sea Ice - Trends]

As you might expect deep water is colder than hot water at the surface getting heat from the sun. When hurricanes churn the waters with their 100mph+ winds cold waters below are stirred to the surface. Hurricanes gain strength from heat of water and need to keep moving to get stronger.

Here are charts showing SST anomalies in the Gulf of Mexico before and after Hurricane Katrina, a Catagory 5 Hurricane.

Presumably in the days after the storm past a SST positive anomaly (+ve?) became a negative one.

The same thing happens during strong storms over polar waters. Negative SST anomalies can be caused by cold water getting churned up from below by a big storm.

Here's the GFS for the day before this SST anomaly chart (the first beng posted showing warm anomaly above Iceland. Note the absence of a big storm. Here's the GFS for a few days before the most recent SST anomaly chart (the second beng posted showing cold anomally above Iceland). Little more activity might partly explain cold anomaly.

Too much might be read into SST anomalies as they can go up and down due to the presence above it of a single storm, which may be caused by a whole host of other factors, irrespective of a cold or warming trend. I'm not saying SST are not unimportant - if you want cold winter you won't care how the anomaly came about. Great, it's cold! However if you're looking for signs of cold winter i think steve murr indicated our prayers for lower STTs should not be at expense of wanting a more southerly Jet Stream than last year.

[Sst's And Sea Ice - Trends]

Close up of the sst anomaly chart.

Note: North Sea SSTs currently running 1+/ 2+

[Snow/wintry Precipitation Reports: 22nd February]

15.00 the sixth snow shower in couple of hours starts, Nr. Burham SE Essex. This snow shower is heavy, some graupel mixed in, and looks like it means business. Visibility very poor and sticking even to concrete surfaces. Temperature on first flake 3.5c. Temperature 12 minutes later 0.5c! Great snowflakes now, want it to last, suddenly what landscape we can see looks wintry!

[Snow/wintry Precipitation Reports: 21st February]

12:40am, Nr Burnham, SE Essex.

Light snow, very wet and small flakes. Settling on surfaces previously covered in hail but not concrete.

Temp about, not much less than 2c. Passes for a "dusting."

[Wintry Precipitation Terminology...]

... really confuses me. What's the difference between hail and graupel? Wet snow and sleet? I haven't a clue and I don't think my snow reports are accurate. http://nwstatic.co.uk/forum/public/style_emoticons/<#EMO_DIR#>/cool.gif Having read a lot of googled definitions I'm more confused than ever!! However, I'll post some of my finds for your interest.

While we still have slightly milder conditions the eagle-eyed may be lucky enough to see all the different types!

You don't have to read all the definitions!

There may be better definitions/precipitations type to add that I've not mentioned.

Hail

Precipitation that originates in convective clouds, such as cumulonimbus, in the form of balls or irregular pieces of ice, which comes in different shapes and sizes. Hail is considered to have a diameter of 5 millimeter or more; smaller bits of ice are classified as ice pellets, snow pellets, or graupel. Individual lumps are called hailstones. It is reported as "GR" in an observation and on the METAR. Small hail and/or snow pellets is reported as "GS" in an observation and on the METAR.

www.weather.com/glossary/h.html

Falling ice in roughly round shapes at least 0.2 of an inch in diameter. Hail comes from thunderstorms and is larger than sleet. Hailstones form when upward moving air -- updrafts -- in a thunderstorm keep pieces of graupel from falling. Drops of supercooled water hit and freeze to the graupel, causing it to grow. When the balls of ice become too heavy for the updrafts to continue supporting them, they fall as hailstones. Sleet, in contrast, consists of raindrops that freeze on the way down.

www.usatoday.com/weather/wds8.htm

Precipitation in the form of balls or irregular lumps of ice. Tall cumulonimbus clouds are much warmer at the bottom than at the top. This causes tremendous pressure differences and strong rising air currents, which suck warm water droplets from the bottom of the clouds to the top. There, they freeze. If the currents are strong enough, a hailstone will fall and rise many times, causing several layers of ice to build up until the hailstone is heavy enough to fall from the cloud

www.northcountryweather.com/weather_glossary.html

Hail is a destructive form of precipitation that is 5 to 190 millimeters in diameter. The large downdrafts in mature thunderstorm clouds provide the mechanism for hail formation. Hailstones normally have concentric shells of ice alternating between those with a milky appearance and those that are clear. The milky white shells, containing bubbles and partially melted snowflakes, correspond to a period of rapid freezing, while the clear shells develop as the liquid water freezes much more slowly.

www.geog.ouc.bc.ca/physgeog/physgeoglos/h.html

is precipitation composed of lumps of ice. Hail is produced when large frozen raindrops or other particles in cumulonimbus clouds, grow by accumulating supercooled liquid droplets. Violent updrafts in the cloud carry the particles up through the freezing all; allowing the frozen core to accumulate more ice. when the piece of hail becomes too heavy to be carried by rising air currents, it falls to the ground.

www.met.gov.sb/learn/glossaryfn.htm

Variations in temperature, migration of liquid and vapor water, and pressure of snow cover may result in rounded snow pellets from 2 to 5 mm diameter. Graupel is visually similar to hail, but lacks the banded outward growth pattern of hail.

ebeltz.net/glacglos.html

Graupel See image.

A form of frozen precipitation consisting of snowflakes or ice crystals and supercooled water droplets frozen together.

www.weather.com/glossary/g.html

A type of precipitation that consists of a snow crystal and a raindrop frozen together.

www.geog.ouc.bc.ca/physgeog/physgeoglos/g.html

Small pellets of ice created when supercooled water droplets coat, or rime, a snowflake. The pellets are cloudy or white, not clear like sleet, and often are mistaken for hail.

www.usatoday.com/weather/wwterms.htm

A form of frozen precipitation consisting of snowflakes or ice crystals and supercooled water droplets frozen together. Also known as snow pellets.

www.cagenterprises.com/wx_glossary_g.html

Sleet

partially melted snow (or a mixture of rain and snow)

www.cogsci.princeton.edu/cgi-bin/webwn

Pellets of ice that form when rain or melting snowflakes freeze while falling. (Occurs in cold weather; hail usually occurs in summer.)

asd-www.larc.nasa.gov/asd_over/glossary/w.html

Generally refers to a mixture of rain and snow or falling snow that is melting into rain

www.bom.gov.au/lam/glossary/spagegl.shtml

Rain drops that freeze into ice pellets before reaching the ground. Sleet usually bounces when hitting a surface and does not stick to objects. Forms when snow enters a warm layer of air above the surface and melts and then enters a deep layer of sub-freezing air near the surface and refreezes.

deved.meted.ucar.edu/mesoprim/glossary.htm

Also known as ice pellets, it is winter precipitation in the form of small bits or pellets of ice that rebound after striking the ground or any other hard surface. It is reported as "PE" in an observation and on the METAR.

vwsri.netfirms.com/glossary/s.html

Drops of rain or drizzle that freeze into ice as they fall. They are usually smaller than 0.3 inches in diameter. Official weather observations list sleet as "ice pellets." In some parts of the country "sleet" refers to a mixture of ice pellets and freezing rain.

www.usatoday.com/weather/wds8.htm

Freezing Rain See image.

Rain that falls as liquid and freezes upon impact to form a coating of glaze on the colder ground or other exposed surfaces. It is reported as "FZRA" in an observation and on the METAR.

www.weather.com/glossary/f.html

Rain that turns to ice on impact with the surface.

asd-www.larc.nasa.gov/asd_over/glossary/w.html

Type of precipitation. Occurs when rain hits a cold surface and freeze. For this to occur a surface temperature inversion is required. In such an inversion, the surface must have a temperature below freezing, while the temperature of the atmosphere where the precipitation forms is above freezing. Surface inversions may develop from a variety of causes, but typically they occur near the leading edge of cold air from the north as it pushes southward.

www.geog.ouc.bc.ca/physgeog/physgeoglos/f.html

Snow

precipitation falling from clouds in the form of ice crystals

www.cogsci.princeton.edu/cgi-bin/webwn

Frozen precipitation in the form of white or translucent ice crystals in complex branched hexagonal form. It most often falls from stratiform clouds, but can fall as snow showers from cumuliform ones. It usually appears clustered into snowflakes. It is reported as "SN" in an observation and on the METAR.

vwsri.netfirms.com/glossary/s.html

Type of precipitation that forms in air with temperatures below freezing. Snow forms when water vapor deposits directly as a solid on a deposition nuclei, by passing the liquid state. A snowflake forms first as a very tiny crystal developing on a six-sided hexagonal deposition nuclei. The ice crystal then grows fastest at the six points as these area are more directly exposed to the atmosphere's water vapor. Snow is most common in winter just north of the center of mid-latitude cyclones. As the warm moist air travels around the center of lowest pressure, it overrides colder air located north of the low and is cooled to its saturation temperature, producing rainfall and snow. Snow generally occurs with east winds, since the winds at locations north of a mid-latitude cyclone are from the east.

www.geog.ouc.bc.ca/physgeog/physgeoglos/s.html

Falling ice composed of crystals in complex hexagonal forms. Snow forms mainly when water vapor turns directly to ice without going through the liquid stage, a process called sublimation.

www.usatoday.com/weather/wds8.htm

Snow grain

Very small snow crystals. The ice equivalent of drizzle. [snizzle?]

Thundersnow

A thunderstorm with snow instead of rain falling on the ground.

[Snow/wintry Precipitation Reports: 21st February]

Nr. Burnham, SE Essex.

8.15 - 2c, hail shower, 5minutes. Left rooftops and some ground surfaces white with 1cm of ice.

8.20 - Thunder sleet and hail mix, 5 minutes.

8.30 - 90% hail, sleet, drizzle mix plus some tiny snowflakes, mostly light falling like rain when heavier. Lasted 15 minutes.

Everything but snow - but entertaining weather nonetheless! First time I've heard thunder with wintry weather. B)

[Snow/wintry Precipitation Reports: 21st February]

17.50. SE Essex, nr Burnham, 30 second hail shower followed by what looked like rain but didn't feel (get) wet when I stuck my hand out in it.

Freezing rain? It wasn't white, or round. Lasted 15-30 seconds. It's dark so cannot be sure of observation.

No settled snow.