Strong Local Storms and 2 Tropical Systems…I Mean One.August 10th, 2012 at 8:46 am by Jeremy Wheeler under Weather
We’ll get to the tropics in a bit. Let’s first focus on the local storms that will be brewing today. We are under a slight risk for severe weather as the upper level winds in the region will be stronger than they have been over the last few days:
The main threats will be straight-lined winds. If the sun pops out for a while, then the hail threat will increase. An isolated tornado can’t be ruled out, but it is not the main threat today. Luckily this morning we have had a lot of clouds and there are already some showers and storms in the region.
If the clouds stay thick, then that should limit the amount of instability (storm energy) this afternoon. Regardless the upper level winds will be stronger today with the wind shear picking up to about 30-35 knots which is about the minimum amount of support for severe weather when you have light to moderate instability. Remember wind shear can weaken tropical systems, but it helps storms over land as it bends the storm sideways and pushes the rain away from the warm updraft (rising air). Otherwise the storms can cutoff their own warm/moisture supply. Strong upper level winds can also sometimes act to lift the storms from above.
We will be warm today, but the amount of heat again depends on the clouds. For now I’m forecasting highs in the upper 80s. A few 90s are possible. Winds will be breezy at the surface. They will be out of the south at 10-15mph with some gusts up to 25mph. The moisture is high today and tomorrow with dewpoints in the low/mid 70s expected.
Tonight we’ll see more scattered showers and storms, but it should taper off for a while. Tomorrow we’ll have more rain and storms as the cold front moves into Hampton Roads. The rain won’t last all day, but the showers will be on and off through the period. The chance for rain today is 70%. Tomorrow it is 60%. The slow moving front should push through by late Saturday night. Early Sunday morning a few showers may linger behind the front. I’m thinking that we will dry out by late morning though. This should give us some nice weather Sunday afternoon and again on Monday. Cross your fingers that the front doesn’t get hung up over the viewing area. Otherwise rain may continue into midday Sunday. At least south and east. For now I’m betting on dry.
In the tropics there two…I mean One…I mean two systems.
I thought it was odd this morning that the National Hurricane Center kept Ernesto as a tropical storm when they had trouble even finding a center of circulation as stated in their morning discussion. So that’s why I played with the 1-2-1 title. It is grinding down though to a very weak area of low pressure. But it is still producing heavy rain over central Mexico. Some models have it moving into the Pacific and becoming a system again. We’ll see.
The new boy in town is tropical depression number 7. Lucky 7 right? This system was located about 950 miles east of the Leeward Islands. It had a pressure this morning of 1009 mb (millibars) and a maximum sustained wind of 35mph. It is heading west. It is moving over warm ocean waters and a low wind shear environment, but it also has some dry air wrapping into the system. So it should strengthen slowly until it shakes that off. When the winds do get over 39mph, then it will become Gordon.
Towards the end it looks like Gordon will head a little farther north than Ernesto’s path. We’ll have to watch for updates as the system gets more organized.
Finally, the US Drought Monitor updated yesterday. No surprise even more of the country is in a drought now. Especially extreme drought. There is severe drought now over Maryland just to our north.
Meteorologist: Jeremy Wheeler