Jan 14, 2010

Ireland Snow & North Pacific Jet Stream

It's not just Britain that has become completely snow covered - Ireland was also completely covered with snow on January 11/12.
from national ice center
It was reported that on the 10th several centimeters of snow forced Cork airport in extreme southern Ireland to close. Snow also covers most of France and even Spain. Normally, snow cover wouldn't even extend west of Germany:In the Pacific, a 220 knot jet stream has developed east of Japan at about 35N latitude.This jet stream is a result of the temperature contrast between the warm North Pacific Current, which is now up to 57F at 40N latitude, and the arctic air over Alaska, which was as cold as -51F at Bettles and -56F at Fort Yukon today. A 952 mb surface trough developed in the left exit region yesterday at 45N latitude.Today, it deepened to 947 mb and is at 49N.The water vapor imagery speaks for itself:When that jet stream hits California next week, widespread flooding can be expected.Given this trajectory, cooler conditions are likely to follow for the west coast. This is what is indicated by the latest GFS:

Jan 11, 2010

Welcome To The Winter Of 09/10

Despite what the Climate Prediction Center is now calling "a strong El NiƱo", and a brief weakening of the Walker circulation in mid-late December, most of North America and Eurasia are having their worst winter in decades. Unusual cold and snow has been reported from India to Russia to Poland to Germany to France to Britain to The United States to even Peru. While extreme cold continues in Beijing, Seoul, South Korea was hit with 11 inches of snow on January 4th - the heaviest in a single day since records began in 1937. In Britain, one of the coldest winters in a century is causing gas shortages and a series of brutal snowstorms have the entire country snowcovered:Image from Terra on January 7
In the The United States, a nor'easter dumped 37.6" of snow on Burlington, VT on January 1-3. Most of the country had a very cold December:And so far January has been even colder:The above chart captures only part of the recent record breaking cold outbreak which began on January 7th as a very strong clipper pulled arctic air into the Plains while hitting Chicago O'Hare with 7.5" of snow.Hard freeze warnings (dark blue) were already in effect along the Gulf Coast from Galveston to New Orleans to Mobile.Wind chill warnings were issued for the Northern Plains and a heavy freezing spray warning for Lake Superior. By the morning of the 8th, temperatures had plunged into the -30s in the Dakotas and already hit below zero in Kansas City and as far south as the Texas Panhandle. When a cold front from a weaker southern trough hit Brownsville, Texas on the 7th the temperature dropped from 67 at noon to 45 at 3PM. The next day, arctic air poured in and the dewpoint hit 11. By the morning of 9th, the temperature was 29, and barometer read 1036.3 mb (30.61"). Hard freeze warnings now ran from Brownsville to Jacksonville as freeze warnings and wind chill advisories extended into southern Florida.The cold front, now reinforced with arctic air, surged across the entire Gulf Of Mexico in just 36 hours:When the cold front hit buoy 42055 in the Bay Of Campeche on the 8th, the winds went from a calm 2 knots to a stormy 27 knots in no more than an hour:The waves went from 2 feet to 14:And the air temperature went down to a chilly 61: Buoy 42056 between Cancun and the Cayman Islands experienced similar conditions:Although 42055 does not report dewpoint, 42056 does - it went down to 51:Even at buoy 42057 about 200 miles south of the Cayman islands had conditions that were just as bad - if not worse:Here the dewpoint dropped 20 degrees:As the core of arctic air spread across Florida on January 9th, wind chill and freeze warnings were issued for the rest of the peninsula. A wide band of post frontal rain was mixed with sleet at the shuttle landing facility and Orlando, and mixed with snow at Okeechobee. Although not official, snow may have even been spotted at Naples as described in this news story. On the morning of the 10th, low temperatures were 35 at Miami, 34 at Homestead, 32 at West Palm Beach, and the upper 20's in the Everglades. This level of cold has not been seen in Southern Florida since 1989. In the Keys, wind chill advisories had to be issued down to Marathon. This morning (the 11th), Key West had a low temperature of 42, and the dewpoint was as low as 31. Marathon hit 39, with a dewpoint of 28. Also this morning, New Orleans had a low temperature of 19.

All of this underscores the influence of the deep solar minimum and the highly negative arctic oscillation (AO), which hit -5.6 in December - a record for the month:Looking upstream, powerful 200+ knot jet stream has entered the Gulf Of Alaska. It produced a 952 mb storm at 46N that maintained a pressure below 960 mb for 36 hours.