Monday, July 11, 2011

A dangerous heat wave is marching east

Extreme heat from the country's midsection is moving east with a broad upper ridge of high pressure. High heat combined with rich low-level moisture from the Gulf will produce heat index values today ranging 100-115 (120 in some spots!) in the highlighted areas on this map:

(Heat Advisories are in orange, Extreme Heat Warnings are in pink.)
At the upper levels, that broad ridge will mean increasingly hot and humid weather for us in Virginia through Wednesday:

A low pressure system that has been producing severe weather through northern Plains and Upper Midwest over the past 24 hours (riding along the jet stream) will force a cold front into the Mid-Atlantic late Tuesday.

But ahead of the front, we'll be extremely hot and humid in Virginia, with highs in the upper 90s to around 100 degrees. Heat index values in central Virginia will be 100-105 degrees in most locations during the afternoon hours. The high temperature in Richmond Tuesday could break a record for that date, July 12th, which currently stands at 98 degrees from 1986. The hottest temperature so far in 2011 officially at Richmond International Airport has been 98 degrees (May 31, June 9, June 28), so Tuesday could end up being our hottest day of the year so far, as well as a record-breaker for that date! Even though the surface cold front will pass through by early Wednesday morning, it will take a good 24 hours for that rich low-level moisture to be replaced by drier, more seasonable air. You'll really notice the return to seasonable Summer weather by Thursday. But for the first half of this week, please be heat-safe! Check out my story from earlier this year on important heat safety tips you need to know by clicking here.
Stay with CBS6, we'll keep you ahead of the storm.
--Meteorologist Carrie Rose

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