The Storm Prediction Center (SPC) is forecasting a moderate risk for severe weather today and into tonight for portions of the Southern Plains and Southeast. Another tornado outbreak is possible along with large hail and damaging winds. The following is the public discussion released by the SPC this morning at 11:50 CDT:

TORNADOES LARGE HAIL AND DAMAGING WINDS OVER PARTS OF EASTERN
TEXAS NORTHERN AND WESTERN LOUISIANA AS WELL AS SOUTHERN AND EASTERN
ARKANSAS THIS AFTERNOON AND TONIGHT...

THE NWS STORM PREDICTION CENTER IN NORMAN OK IS FORECASTING THE
DEVELOPMENT OF TORNADOES...LARGE HAIL AND DAMAGING WINDS OVER PARTS
OF EASTERN TEXAS...NORTHERN AND WESTERN LOUISIANA AS WELL AS
SOUTHERN AND EASTERN ARKANSAS THIS AFTERNOON AND TONIGHT.

THE AREAS MOST LIKELY TO EXPERIENCE THIS ACTIVITY INCLUDE

- EASTERN AND SOUTHERN ARKANSAS
- NORTHERN AND WESTERN LOUISIANA
- EASTERN TEXAS

ALSO...A THREAT FOR OTHER SEVERE THUNDERSTORMS ARE EXPECTED FROM
CENTRAL TEXAS EASTWARD ACROSS THE LOWER MISSISSIPPI VALLEY AND
NORTHWARD INTO THE WESTERN PORTIONS OF TENNESSEE AND KENTUCKY.

A POTENT UPPER LOW AND STRONG JET MAX WILL MOVE EAST ACROSS
TEXAS/LOUISIANA AND ARKANSAS LATER TODAY AND TONIGHT...WITH A
SURFACE LOW AND COLD FRONT SHIFTING FROM EASTERN TEXAS ACROSS THE
LOWER MISSISSIPPI VALLEY TONIGHT. AHEAD OF THIS FRONT...THE
COMBINATION OF A MOIST AIR MASS...DAYTIME HEATING AND COOLING ALOFT
WILL RESULT IN AN UNSTABLE ENVIRONMENT FAVORABLE FOR WIDESPREAD
SEVERE THUNDERSTORMS...ESPECIALLY FROM MID AFTERNOON THROUGH
MIDNIGHT. THE WIND SHEAR WILL BE QUITE STRONG...AND FAVOR
TORNADOES...SOME STRONG...ESPECIALLY ACROSS NORTHEAST TEXAS...
NORTHERN LOUISIANA AND ACROSS PORTIONS OF SOUTHERN AND EASTERN
ARKANSAS. ALTHOUGH TORNADOES ARE ALSO POSSIBLE ACROSS SOUTHEASTERN
TEXAS AND LOUISIANA...A SQUALL LINE IS EXPECTED TO DEVELOP AND MOVE
ACROSS THIS REGION LATE THIS AFTERNOON/EVENING...WITH DAMAGING
STRAIGHT-LINE WINDS MORE LIKELY.

STORMS WILL CONTINUE EASTWARD INTO MISSISSIPPI...WESTERN TENNESSEE
AND WESTERN KENTUCKY OVERNIGHT WITH A THREAT OF DAMAGING WINDS AND
ISOLATED TORNADOES.

THOSE IN THE THREATENED AREA ARE URGED TO REVIEW SEVERE WEATHER
SAFETY RULES AND TO LISTEN TO RADIO...TELEVISION...AND NOAA WEATHER
RADIO FOR POSSIBLE WATCHES...WARNINGS...AND STATEMENTS LATER TODAY.

A severe weather outbreak occurred across the Tennessee Valley, southern Appalachians and into central Georgia/South Carolina, starting Friday, March 14th and continuing into today. One supercell thunderstorm developed west of Atlanta, quickly intensified and drug a tornado directly across downtown Atlanta causing extensive damage to many structures (including high-rises). The following HAMrad II animation shows the storm as it moved through downtown Atlanta and finally weakening after passing to the east of the city. The National Weather Service reported that based on the damage investigation, this tornado was an EF-2 with winds up to 130 mph and a path of about 6 miles.

The following is the official NWS report regarding their damage investigation on the Atlanta tornado:

0938 PM     TORNADO          1 NW ATLANTA            33.77N 84.43W
03/14/2008  F2               FULTON             GA   EMERGENCY MNGR

            NWS DAMAGE SURVEY CONCLUDED AN EF2 TORNADO 6 MILES LONG
            AND 200 YARDS WIDE TUCHED DOWN AT SIMPSON AND BURBANK
            ROAD AT 938 PM. IT MOVED ACROSS DOWNTOWN ATLANTA AND CAME
            UP AT THE CORNER OF BRAEBURN AND JOSEPHINE ROAD IN
            WESTERN DEKALB COUNTY.

Earlier today additional supercell thunderstorms developed across the northern suburbs of Atlanta bringing additional storm damage in the form of very strong winds, large hail and even several tornadoes. Several moved close to the HW offices in Kennesaw, including the storm depicted in the following image which brought up to 3″ diameter hail and a possible tornado near Canton just to the north of our offices.

The following map shows the official NWS storm reports across Georgia since yesterday, the second of which only showing the tornadoes and/or funnel clouds that were reported (click for full-size image).

Is it going to be colder than normal? I’m going on vacation in June, what will the weather be like?
These are common questions that we are often asked. To help answer these questions, we are introducing the new climate area, accessible via:

http://climate.hamweather.com

The new climate area incorporates data from several sources into a user friendly and easily accessible format. Some of the great features of the climate area include:

• Records Events - View the records set over the past couple days, the past week or even a specific date from the past couple years. You can mouse over the map to view individual records or in tabular format below the map.
   
• Normals – HAMweather has created a collection of maps that detail the normal precipitation, highs, lows and mean temperatures for all 365 days of the year, as well as monthly and yearly summaries. Maps are available for the Continental US, 9 regional views, Alaska and Hawaii.One of my favorite maps from this set is the CONUS view of the yearly precipitation. This map allows you to easily depict the drier conditions east of the Rockies and the increased areas of precipitation in the southeast by the Gulf of Mexico.

  Another great feature of the Normals area and many of the other maps is the ability to click on a regional map to view a tooltip of the data near the location clicked on the map:
  
  In the tooltip you can click the “More Details” link to view the normals in tabular form, either a daily view for the month or a monthly view for the year.
   

• Temperature Change – The improved temperature change maps provide the change in temperature as compared to 24 hours ago, as well as 1 hour ago. Like most of the other regional views, clicking on the map will display more information for the location clicked:
  
  The southeast was definitely much cooler the morning of the Feb 27^th than it was the morning of Feb 26^th!
   
• Forecasted Departure from Normal Highs (and Lows) – As part of the short-term outlooks, these maps are providing the forecasted departure from the normal highs and lows for days 1 through 7.
  Here we can see the forecasted highs for the central plains on Feb 28^th, look to be above normal.
  
• Long Term Outlooks – This map set, based on data provided by the NOAA Climate Prediction Center, display the probabilities of the temperatures and precipitation being above or below normal for a specific time range. Available ranges include days 8-14, the next month and for the next year in three month intervals.

Upcoming HWClimate Service
Within the next couple of weeks, HAMweather will begin offering a HWClimate content service. With this service, you will be able to add custom branded map images and data to your websites, visual displays, mobile devices and more. More details to come.

Once the Northeastern storm exists stage right Friday night, a new storm begins affecting the West Coast on Saturday and continuing through Sunday, bringing heavy snows once again to the mountains with heavy rainfall across Oregon and California. The storm center will make landfall farther south than previous systems which will give western Washington and British Columbia a break from the continuous rain and snows of the last week. The country east of the Rockies will get a much needed break for most of the weekend before another storm system begins taking shape later Sunday afternoon and evening across the Southern Plains. As milder Pacific air continues to flood the country next week, many areas will see rain with this next system with the exception being the usual areas where it wants to snow this year–the northern Plains and far northern parts of New England. Severe weather will once again be possible across the Gulf Coast states as the accompanying cold front scours out high levels of moisture engulfing the region from the Gulf and Pacific.

Not only will a major winter storm be sweeping across the country this weekend, but another very strong storm will slam into the Pacific Northwest by the end of the weekend. Heavy snows will be likely across the northern tier of the US, especially northern sections of the Midwest and Northeast. This system will quickly intensify once it reaches the coast of New England and will threaten to bring blizzard conditions across portions of Maine, Vermont and New Hampshire on Monday and Tuesday. Meanwhile the storm system moving into the Pacific Northwest will bring widespread snow across all of Washington and northern Oregon as modified arctic air filters south central Canada through the Fraser Valley region. However, as the storm approaches the coast on Sunday it will bring very strong southerly winds to the region, increasing temperatures at the surface and upper levels. Precipitation that began as snow will transition to very heavy rain on Sunday and into Monday with much higher snow levels.

A strong cold front is sweeping across the country and will continue to do so through the upcoming holiday. The most dramatic changes will occur across the Central and Southern Plains where temperatures will be 30-40 degrees colder on Wednesday than today. Rain and thunderstorms will become more widespread Wednesday along and ahead of the front and will continue into Thanksgiving day from the Gulf Coast into New England. Some of the moisture will overrun the cold front which will bring a chance of snow showers behind it from the Central Plains northeastward into the Great Lakes region. Overall snow amounts will not be extremely impressive behind the front and will only amount to a few inches in most locations, though amounts can be locally heavy where more moisture is available in the colder airmass. Light snow showers will continue across the Front Range of the Rockies in Colorado and southern Wyoming due to upsloping conditions behind the front.

The primary travel headache on Wednesday will be the persistent wet weather and storms along the frontal boundary. For the major cities across the Northeast, this storm will bring a steady rain as warm, moist air is pulled north across the region. Rain will be mixed with or change over to snow across upstate New York and northern Maine. Expect airport delays in many hubs east of the Rockies on Wednesday, especially for Chicago, Kansas City, Denver and Saint Louis where there is a greater threat of accumulating snowfall.

Keep up to date with the latest weather conditions, advisories and airport delays for the following major US cities likely to be affected by this system:

Atlanta, GA
Boston, MA
Chicago, IL
Denver, CO
Kansas City, MO
New York, NY
Philadelphia, PA
Saint Louis, MO

Much of the country will have quiet weather for Halloween on Wednesday with the exception being Florida and coastal areas of Georgia and South Carolina as Tropical Storm Noel approaches. Windy and rainy conditions will engulf much of Florida, especially the eastern half, throughout the day on Wednesday and continuing into the overnight hours. Weather conditions will improve across the region on Thursday as Noel turns to the northeast away from the Southeast coastline. Elsewhere, a storm system moving across Canada will drag a front through the Midwest bringing showers ahead of and a rain/snow mix behind the front. Windy conditions will prevail behind the front Wednesday night across the Upper Midwest. A weak front will move into the Pacific Northwest on Wednesday with scattered showers lingering into the early evening hours.

Temperatures will be chilly across much of the northern US from the Pacific Northwest eastward into the Midwest. Meanwhile, more pleasant weather will be in store across the South with dry and mild conditions expected.

Wildfires have been raging out of control across Southern California for the past several days, fueled by dry ground conditions, low humidity and very strong Santa Ana (offshore) winds. Large wildfires are reported across seven counties in the region surrounding San Diego and Los Angeles where almost 250,000 acres have burned and thousands forced to evacuate from their homes and communities. Winds have peaked well over hurricane force and in several cases have reached as high as 100 mph. High wind and fire advisories remain in place for the region as conditions will remain quite favorable for continuing and additional wildfires.

Our SuperSat imagery (via HAMsat) clearly depicts the smoke rising from the fires on the ground as well as the strong Santa Ana winds carrying the smoke plumes westward over the eastern Pacific. The following image was from around 4:30 PM EDT (1:30 PM PDT) which shows the major fires burning at the time. The clockwise flow around the strong area of high pressure which is helping to create the strong offshore winds can also be seen as the smoke begins to flow more towards the northwest once over the Pacific Ocean.

Click here to view a 9-hour animation of the smoke plumes (~6.5mb).

View the latest HW SuperSat image for Southern California (Sector 24) and the Baja Peninsula (Sector 25).

Click the image below for the full version.