Thursday, January 31, 2013

Severe Weather from Texas to Pennsylvania

Over the last two days a strong low pressure system and vigorous cold front generated a smorgasbord of inclement weather across the central and eastern U.S., snow.


Loop of surface weather from 10:00 p.m. January 28 to 7:00 a.m. EST January 31.

This system generated the first widespread severe weather outbreak of the new year.  Severe thunderstorms occurred from Texas to Pennsylvania and through the Deep South.

Storm reports for January 29 (left) and January 30 (right).
Tornadoes touched down in Arkansas, Missouri, Louisiana, Kentucky, Tennessee, and Georgia. One person was killed and 14 were injured in Adairsville, Georgia when a tornado struck causing major damage. Eight people were injured near Calhoun, Georgia. Survey teams from the National Weather Service have been deployed to assess the damage and some information will be available later today. Visit the NWS Peachtree City (Atlanta) web site for the latest updates.


Heavy rain and snow melt earlier this week resulted sharp rises and ice break up on rivers and streams in Wisconsin, Illinois, Michigan, and Indiana have resulted in localized flooding. Flooding is likely to continue to be a threat through this weekend.

In the wake of this system, the rain changed to snow and a swath of 4 to 8  snow fell from Nebraska northeast through Wisconsin yesterday.


Although this powerful weather system has moved offshore, lake-effect snow and snow showers will continue today in the eastern U.S.

Saturday, January 26, 2013

Crazy Winter Weather in the UK

M6 on Friday night
M6 in dark blue














 
Heavy snow Friday and Saturday paralyzed travel in western and northern England and Scotland. Motorists were stranded from 8 to 10 hours on M6, the longest and busiest highway in the UK.Stranded motorists entertained themselves building snowmen in the road, walking their dogs, and having snowball fights. Many cars were abandoned on the highway as well. In addition to closing numerous highways, the heavy snow caused a roof collapse, closed airport runways, and delayed rail travel.  Six inches of snow fell in many areas, with up to a foot reported. The Daily Mirror reported that a foot of snow fell in an hour, which is a rate not even seen in lake effect events. It is unlikely this rate occurred and other sources did not confirm this.


Now that the snow has ended, warmer temperatures and heavy rain are causing flooding problems in these same areas.Flooding is particularly serious in Wales, and rain is expected through Sunday morning.

The warning map for Sunday issued by the UK Met Office.

Thursday, January 24, 2013

Rare Freezing Rain Event in Salt Lake City

Residents of Salt lake City woke up to some unusual weather conditions today. A light freezing rain that began before dawn was coating exposed surfaces with ice. The temperature when the precipitation started was only 20°F, and temperatures remained below freezing all day. There was only .09 inches of rain, but temperatures well below freezing it takes very little rain to create an icy mess.

Radar image from Salt Lake City at 5:00 MST January 24.

The glaze of ice turned roads, interstates, and parking lots into skating rinks. At 9:00 a.m. MST all runways of the Salt Lake City International Airport were closed to departures, and it was past mid afternoon before two runways could be opened. It was the first time in 24 years the airport was closed due to ice.Since 1940 there have been only nine other freezing rain events recorded at the airport. The 0.09 inches of freezing rain measured today was the greatest since December 31, 1983. There were dozens of weather-related accidents, and dispatchers reported more than 240 reports of other accidents and slide-offs. 

Freezing rain fell as far north as Boise, Idaho. The Idaho Transportation Department closed a 70-mile stretch of Interstate 84 between Boise and Glenns Ferry this morning, and schools closed because of the weather conditions.

Schematic of freezing rain formation.
Credit: University of Illinois Department of Atmospheric Sciences.
Freezing rain occurs when rain becomes supercooled and freezes on impact with objects on the surface.  Typically snow falls though an elevated warm layer where the snow melts and becomes rain. The rain then falls through shallow layer of cold air near the surface, where they become supercooled. When the rain hits objects below freezing (the ground, trees, power lines, etc.) it immediately freezes.




The atmospheric sounding at Salt Lake City this morning exhibited this typical profile in fairly dramatic fashion.


Southwest flow ahead of a system approaching from the Pacific Northwest brought warm and moist air into the region at mid-levels while very cold air hugged the surface in the valleys. The cold air layer near the surface was only about 900 feet deep, while the warm layer immediately above was approximately 3700 feet deep. This set up the unusual freezing rain event in northern Utah this morning.



Read more here: http://www.idahostatesman.com/2013/01/24/2424526/freezing-rain-fell-all-night-in.html#storylink=cpy

Tuesday, January 22, 2013

Lake-Effect (and Pond-Effect) Snow

The lake-effect snow machine in full gear today as frigid Arctic air continues to stream over the open waters of the Great Lakes.

Surface temperature (left) and winds (right) at 11:00 EST
Regional radar at 11:21 EST
Visible satellite at 11:02 EST

Up to 6 inches of snow has fallen in southwestern Michigan, with another 1 to 3 inches expected today. Up to 15 inches of snow is possible in the western Michigan Upper Peninsula. In western New York a  Lake Effect Snow Warning is in effect until 10:00 EST Wednesday morning.  Six to 12 inches of snow are expected today, 6 to 12 tonight, and another 1 to 2 inches on Wednesday. This is on top of 12 to 18 inches in some areas as of this morning. A CoCoRaHS observer in Chautauqua County (NY-CQ-19, Ripley 4.3 SSW) had a 24-hour total of 18 inches this morning, with most of it falling before 7:00 p.m.last night. A Lake Effect Snow Warning is also in effect for northeastern Ohio, where one to three feet of snow may accumulate in the more persistent snow bands.

"Lake-effect" snow resulting from cold air streaming over smaller water bodies can occur as well. Snow bands developed downwind of a number of power plant cooling ponds in northern Illinois this morning.


Sunday, January 20, 2013

5,400 Gray Dots

Today's CoCoRaHS national precipitation map was rather striking because of the lack of precipitation across the country. Of the 5,968 reports submitted as of this post, only 293 reported measurable precipitation, and of those 74 were just 0.01 inch.  There were also 264 trace reports.


A significant number of the measurable rainfall reports came from the east coast of Florida. Lake-effect snow produced some half-inch precipitation amounts and 4 to 8 inches of snow in northern Michigan. Snow also fell throughout much of Maine.


24-hour snowfall map for 7:00 a.m.local time January 20.


High pressure over much of the lower 48 states and a dry Arctic air mass pushing south is the reason why much of the country was precipitation-free.

Surface weather map for 9:00 p.m. CST January 20.

Thursday, January 17, 2013

Winter Comes to Southern Appalachians

Winter Storm Warnings are in effect today and tonight for an area from east-central Mississippi through northern Georgia, much of western North Carolina, most of Virginia and Maryland.

Warnings and advisories in effect as of 11:00 a.m. EST January 17.
Pink areas designate Winter Storm Warnings, violet areas designate Winter Weather Advisories

Surface map at 7:00 a.m. EST January 17.
A low pressure system centered over northern Georgia will move east-northeast today. As cold air comes in behind this system rain will change to snow, and in some areas, freezing rain. The potential for the heaviest snow is in the mountains of eastern Tennessee, western North Carolina, and southwestern Virgina.

Probability of at least 4 inches of snow (left) and 8 inches of snow (right)
for the 24 hour period ending 7:00 EST Friday, January 18.
The good news is that high temperatures the next few days will be well above freezing and much of the snow will melt by early next week.

Maximum temperature forecast for Sunday, January 20.


Tuesday, January 15, 2013

Record Cold West, Record Warmth East

Low temperature records were set from Oregon and Utah south through southern California the past two days, while in the eastern U.S. record high temperatures were recorded in the southeast and mid-Atlantic.

Surface temperatures at 3:00 p.m EST January 14 (left), and at 7:00 a.m. PST January 15 (right).

The reason for this was a very amplified upper air pattern, with a ridge in the Pacific and a ridge in the Atlantic, with a broad and deep trough in between.

500 millibar map for January 14, 2013
In the west, strong northerly winds aloft brought air south from the Yukon and Northwest Territories. In the east, air was being drawn from the Pacific through Mexico and the Gulf of Mexico.

There were numerous record lows in the west the last two mornings.



LOCATIONCOUNTYRECORDPREVIOUSYEAR
 Period of
ARIZONA




     Record
WILLIAMS COCONINO                       -6 -5 1898
105
SHOW LOW AP NAVAJO                         0 0 1968
45
PARADISE COCHISE                        6 13 1922
31
PAYSON GILA                           8 8 1964
62
WILLCOX COCHISE                        9 9 1963
105
SAN SIMON COCHISE                        9 12 1944
54
BAGDAD YAVAPAI                        11 12 2007
73
DOUGLAS BISBEE INTL AP COCHISE                        11 11 1964
67
NATURAL BRG GILA                           11 11 1964
64
FT THOMAS 2 SW GRAHAM                         11 15 1992
42
AGUILA MARICOPA                       14 15 1964
60
TUZIGOOT YAVAPAI                        15 16 2007
35
SASABE PIMA                           15 19 1963
46
WIKIEUP MOHAVE                         17 19 1964
50
WITTMANN 4SW MARICOPA                       18 20 1963
34
TUCSON INTL AP PIMA                           21 23 1963
68
FOUNTAIN HILLS MARICOPA                       23 31 1992
30
CALIFORNIA





BODIE CA ST HISTORIC PARK MONO                           -27 -26 2007
58
JESS VALLEY MODOC                          -13 -5 1962
62
SOUTH LAKE TAHOE AP EL DORADO                      -11 -7 1997
43
TULELAKE SISKIYOU                       -5 -4 1962
76
MC CLOUD SISKIYOU                       5 7 1932
96
SANDBERG LOS ANGELES   15 20 2007
64
DAGGETT AP SAN BERNARDINO  16 16 1963
64
MT WILSON CBS LOS ANGELES  16 18 1962
59
CACHUMA LAKE SANTA BARBARA 21 25 1955
55
BORREGO DESERT PARK SAN DIEGO                      27 28 2007
45
LOS ANGELES DWTN USC LOS ANGELES 34 36 2007
99
IDAHO





STANLEY CUSTER                         -32 -30 1923
51
GRACE CARIBOU                        -24 -20 2007
101
MAY 2SSE LEMHI                          -20 -15 1960
65
CHILLY BARTON FLAT CUSTER                         -20 -20 1964
62
IDAHO FALLS FAA AP                                -19 -17 1964
53
MACKAY LOST RIVER RS CUSTER                         -18 -18 1932
101
CRATERS OF THE MOON BUTTE                          -15 -9 2007
52
PALISADES BONNEVILLE                     -14 -12 1962
51
PRESTON FRANKLIN                       -14 -10 1985
37
PAUL 1ENE MINIDOKA                       -13 -4 1985
73
IDAHO CITY BOISE                          -13 -11 1930
100
MIDDLE FORK LODGE CUSTER                         -8 -8 2007
41
NAMPA SUGAR FACTORY CANYON                         2 3 1986
31
NEW MEXICO





NAVAJO DAM SAN JUAN                       1 2 1975
46
GRAN QUIVIRA NATL MON SOCORRO                        2 2 1964
76
COCHITI DAM SANDOVAL                       3 5 1977
32
GLENWOOD CATRON                         7 9 1964
60
HACHITA GRANT                          9 9 1989
84
NEVADA





MONTELLO 2NE ELKO                           -27 -14 1932
99
ELY AIRPORT WHITE PINE                     -24 -17 2007
81
RUTH WHITE PINE                     -24 -19 2007
44
BEOWAWE EUREKA                         -21 -20 1962
94
MCGILL WHITE PINE                     -20 -13 2007
104
RUBY LAKE NWR ELKO                           -17 -8 1964
70
BLUE EGLE CURRANT12SSW NYE                            -15 -13 1985
30
OROVADA 3 W HUMBOLDT                       -14 -14 1917
96
LOVELOCK DERBY FLD AP PERSHING                       -12 -9 1962
60
SUNNYSIDE - LUND 31S NYE                            -7 -7 1989
47
DENIO HUMBOLDT                       -3 3 2005
54
TONOPAH NYE                            -3 8 1932
31
PIOCHE LINCOLN                        1 2 1997
78
AMARGOSA FARMS-GAREY NYE                            14 17 1989
36
SEARCHLIGHT CLARK                          15 19 2007
94
OREGON





BURNS MUNI AP HARNEY                         -11 -4 1989
40
HART MTN REFUGE LAKE                           -10 -3 1962
66
HOWARD PRAIRIE DAM JACKSON                        -6 2 1962
51
LONG CREEK GRANT                          2 2 1997
50
MONUMENT 2 GRANT                          5 8 1997
41
MARION FRKS FISH HATCH LINN                           7 8 2007
63
TOKETEE FALLS DOUGLAS                        15 16 2007
57
IDLEYLD PARK 4 NE DOUGLAS                        18 19 1997
52
UTAH





BRYCE CANYON FAA AP                                -30 -13 2007
42
TRENTON CACHE                          -27 -14 1985
34
EPHRAIM SANPETE                        -26 -21 2007
58
PINE VIEW DAM WEBER                          -22 -22 1964
69
SCIPIO MILLARD                        -22 -21 2007
107
NEOLA DUCHESNE                       -19 -16 2007
49
DEER CREEK DAM WASATCH                        -17 -15 1955
73
HEBER WASATCH                        -16 -16 1964
118
VERNON TOOELE                         -16 -7 1964
45
SANTAQUIN CHLORINATOR UTAH                           -12 -9 2007
92
KANOSH MILLARD                        -7 2 1964
42
HANS FLAT RS WAYNE                          -4 2 1989
32
ARCHES NP HQS GRAND                          -4 -3 1989
32
BOUNTIFUL-VAL VERDA DAVIS                          -3 2 2007
32
NATURAL BRIDGES NM SAN JUAN                       -3 0 2011
45
CEDAR POINT SAN JUAN                       -3 0 1989
50
WENDOVER AP AWOS TOOELE                         -2 0 2007
99
CANYONLANDS-THE NECK SAN JUAN                       -1 2 1989
45
CAPITOL REEF NP WAYNE                          0 2 1989
45
BULLFROG BASIN KANE                           9 11 1968
35

Record maximum temperatures were concentrated in the the southeastern U.S. on Monday, but were recorded as far north as Maine and New Hampshire, including a record tied at Mt. Washington.



LOCATION COUNTY  REC  PREV YEAR   POR
ALABAMA



    
DOTHAN FAA AP HOUSTON                        79 79 1947 70
GENEVA #2 GENEVA                         78 76 2007 36
CENTREVILLE 6 SW BIBB                           73 71 2007 38
OPELIKA LEE                            72 72 2000 52
ARKANSAS




WEST MEMPHIS CRITTENDEN                     70 67 1995 46
FLORIDA




CLERMONT 9 S LAKE                           83 83 2005 61
INVERNESS 3 SE CITRUS                         83 83 1992 88
MAYO LAFAYETTE                      82 82 1950 61
GAINESVILLE RGNL AP ALACHUA                        82 81 1999 50
JACKSONVILLE INTL AP DUVAL                          81 80 1950 65
TALLAHASSEE WSO AP LEON                           81 80 1971 67
JASPER HAMILTON                       81 81 1972 58
FERNANDINA BEACH NASSAU                         80 80 1972 111
PERRY TAYLOR                         79 77 2007 69
QUINCY 3 SSW GADSDEN                        78 78 1989 39
GEORGIA




SAVANNAH INTL AP CHATHAM                        81 78 2007 68
ALMA BACON CO AP BACON                          80 79 2007 64
MILLEDGEVILLE BALDWIN                        80 76 1937 112
AUGUSTA BUSH FLD AP RICHMOND                       80 73 2007 68
HOMERVILLE 5 N CLINCH                         79 79 1960 55
ALBANY CAA AP                                79 79 2007 37
COLUMBUS METO AP. MUSCOGEE                       78 75 1960 65
PLAINS SW GA EXP STN SUMTER                         77 77 1960 56
ASHBURN 3 ENE TURNER                         77 77 1960 51
SAPELO ISLAND MCINTOSH                       77 77 2000 46
SANDERSVILLE WASHINGTON                     76 76 1960 52
CARTERSVILLE BARTOW                         75 71 1960 66
SILOAM 3N GREENE                         75 73 2000 52
ATHENS BEN EPPS AP CLARKE                         74 71 2007 68
LA GRANGE 1N TROUP                          74 73 1937 71
ALLATOONA DAM 2 BARTOW                         74 72 1995 48
LOUISIANA




CLINTON 5 SE EAST FELICIANA                 79 77 2000 34
MARYLAND




FROSTBURG 2 ALLEGANY                       62 62 2005 40
MAINE




AUGUSTA STATE AIRPORT KENNEBEC                       55 54 2006 64
CARIBOU WFO AROOSTOOK                      52 51 2005 72
MISSISSIPPI




YAZOO CITY 5 NNE YAZOO                          81 77 2007 52
WAYNESBORO 2 W WAYNE                          79 78 1971 90
FULTON 3 W ITAWAMBA                       72 72 2007 54
NORTH CAROLINA




ELIZABETH CITY FAA AP                                79 74 1952 42
NEW BERN - ASOS CRAVEN                         79 74 2007 64
GREENVILLE PITT                           78 78 1932 84
WILMINGTON INTL AP NEW HANOVER                    77 75 1950 80
PLYMOUTH 5 E WASHINGTON                     76 76 2005 65
LEWISTON BERTIE                         75 75 1995 51
LONGWOOD BRUNSWICK                      75 75 2005 38
CONCORD CABARRUS                       74 74 2005 77
BURLINGTON FIRE STN #5 ALAMANCE                       74 74 2005 59
ROXBORO 7 ESE PERSON                         74 72 1960 62
SILER CITY 2 N CHATHAM                        74 74 2005 81
REIDSVILLE 2 NW ROCKINGHAM                     73 71 2005 49
PISGAH FOREST 3 NE TRANSYLVANIA                   72 68 2005 71
YADKINVILLE 6 E YADKIN                         71 70 2005 55
ENKA BUNCOMBE                       71 70 2007 41
NORTH WILKESBORO WILKES                         71 70 2005 55
FRANKLIN MACON                          70 68 1952 64
W KERR SCOTT RSVR WILKES                         70 69 2005 47
MURPHY CHEROKEE                       68 68 2005 44
JEFFERSON 2 E ASHE                           67 63 2007 82
TRANSOU ASHE                           63 63 2007 65
BOONE 1 SE WATAUGA                        62 62 2007 31
GRANDFATHER MTN AVERY                          57 54 2007 55
GREENLAND ROCKINGHAM                     60 60 2005 37
NEW HAMPSHIRE




LEBANON CAA AP GRAFTON                        55 51 2006 46
MT WASHINGTON COOS                           43 43 2005 64
NEW YORK




AVON LIVINGSTON                     68 64 1995 83
DANSVILLE LIVINGSTON                     67 66 1995 86
WARSAW 6 SW WYOMING                        64 57 2006 59
PENNSYLVANIA




RIDGWAY ELK                            69 67 1972 98
MONTGOMERY L&D BEAVER                         68 66 1995 49
TIONESTA 2 SE LAKE FOREST                         68 68 2005 67
CHALK HILL 2 ENE FAYETTE                        64 62 1995 35
BRADFORD 4SW RES 5 MCKEAN                         63 60 2006 65
SOUTH CAROLINA




COLUMBIA UNIV OF SC RICHLAND                       82 80 1932 80
COLUMBIA METRO AP LEXINGTON                      81 73 2005 68
DILLON DILLON                         81 81 1907 81
SUMMERVILLE 4W DORCHESTER                     80 80 1907 111
FLORENCE RGNL AP FLORENCE                       79 75 1995 65
CHARLESTON INTL. AIRPORT CHARLESTON                     79 78 1932 83
JOHNSTON 4 SW EDGEFIELD                      78 73 2000 54
BISHOPVILLE 1ENE LEE                            77 77 2005 71
SANDHILL RSCH ELGIN RICHLAND                       77 72 1995 51
MCCOLL 3 NNW MARLBORO                       77 75 1937 75
BAMBERG BAMBERG                        76 72 2005 58
ANDREWS GEORGETOWN                     76 75 2005 42
PELION 4 NW LEXINGTON                      76 72 2005 50
LAURENS LAURENS                        75 75 1937 94
MANNING CLARENDON                      75 75 2007 38
NINETY NINE ISLANDS CHEROKEE                       73 71 2005 50
TENNESSEE




ERWIN 1 W UNICOI                         74 71 2005 33
KNOXVILLE EXP STN KNOX                           71 71 1995 32
ATHENS MCMINN                         70 70 2005 48
VIRGINIA




SOUTH BOSTON HALIFAX                        73 73 2005 31
MARTINSVILLE FLTR PLT HENRY                          72 70 2007 64
PULASKI 2 E PULASKI                        71 63 2007 56
APPOMATTOX APPOMATTOX                     70 69 1995 46
STAFFORDSVILLE 3 ENE GILES                          70 65 2005 42
WYTHEVILLE 1 S WYTHE                          70 70 1932 94
BLACKSBURG NWSO MONTGOMERY                     69 65 1960 58
WEST VIRGINIA




SNOWSHOE POCAHONTAS                     54 52 2005 36