26 June 2012

Brutal heat and Severe Flooding

Posted by Dan Satterfield

Brutal heat is likely from Colorado to the East Coast later this week. This is the NAM forecast model for 4 PM CDT on Thursday.

Highs reached 109 (over 40 degrees C for the rest of the more enlightened the world) in Oklahoma on Monday and it was 105 in Limon Colorado and above 105 across much of Kansas. It even reached 102 in NW Alabama but I think the heat will get much worse later this week and spread over an unusually large region fo the U.S. In 33 years of forecasting I have never seen an NWP model forecast 115 degrees Fahrenheit east of the Rockies but I did today. The increasingly severe drought from Georgia to the Plains will get much worse with this high heat.

Down in Florida this morning, the stalled Tropical Storm Debby is producing flooding rains of over 20 inches. The Sopchoppy river is now forecasted to flood in a few hours at 41 feet! Well above any previous measurement.

image ctsy. NOAA/USGS

Here is the latest long-term drought index-

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TALLAHASSEE FL
1147 PM EDT MON JUN 25 2012

1146 PM HEAVY RAIN 1 ESE SANBORN 30.07N 84.59W
06/25/2012 M20.10 INCH WAKULLA FL MESONET

20.10 INCHES OF RAIN MEASURED OVER THE LAST 24 HOURS.

It looks like it is going to be a long summer. Also, keep  in mind that the raw surface forecasts from the main NWP models tend to underestimate high temperatures. The Model Output Statistics (MOS data) is forecasting hotter than you see in that top graphic and is likely more correct. Arctic sea ice by the way, is dropping like a rock…more on that soon.