Flood Watches For Heavy Rain Later Today Into Friday
Ahead of A Beautiful Weekend
This is going to be a busy weather day as a weather front moves through and stalls and we being to see areas of downpours and thunderstorms break out during the day. Flood Watches are posted over a large geographic area from Northeast Virginia to Southern New England and the risk for flash flooding is elevated. The Weather Prediction Center is indicating that areas from Maryland to New Jersey in particular have a 40 to 70 percent chance for flash flooding while surrounding areas are at a 15 to 40 percent chance.
Here is where it gets tricky regarding forecast rain amounts. In general the way to look at this is that we have a smoothed out map which shows maximum amounts of 2 to 3 inches. However as I have said many times during the summer months, when you are dealing with convection local rainfall amounts can easily be double and sometimes triple the forecast numbers. Here is an excerpt from the forecast discussion from the Weather Prediction Center.
Many individual convective models show localized totals surpassing 5″with even some localized maxima approaching 8″. Residents in the Mid-Atlantic should ensure they have reliable means of receiving warnings issued by their local WFOs throughout the day and into Thursday night.
SATELLITE WITH LIGHTNING STRIKES
WEATHER RADAR
We are also seeing the risk for severe thunderstorms from Northeast Virginia into Southeast Pennsylvania and Southern New Jersey. The Storm Prediction Center is indicating a slight risk or a 15 percent chance for severe thunderstorms. The main issue from these thunderstorms will be strong gusty winds in excess of 55 mph. An isolated tornado spinning up cannot be ruled out though the risk for this is low.
The frontal boundary and the wave that develops on it will enhance heavy rain areas later this afternoon and into the first part of tonight. We should begin to see the rains taper off and end from west to east between 1am and 7am as the front begins to sag southward offshore. The wave goes by early Friday morning to the northeast and this will allow drier air on north to northeast winds to start funneling southward.
A large dome of high pressure is building into the Great Lakes and the Northeast later Friday and into the weekend. This brings very dry and rather cool air for later Friday and through the weekend. In fact this dry dome of air will be with us through Sunday and humidity levels will be very slow to rise next week as another high builds into Southeastern Canada early next week.
As far as temperatures are concerned, Thursday highs will reach the 80s and some areas in South Jersey and points southward could touch 90 degrees, however once the winds shift to the northeast and east later today when the rains come, you can expect temperatures to fall rather quickly. Look for Friday temperatures to be mostly in the upper 60s and lower 70s during the day as that cooler and drier air moves in.
The weekend is going to probably be the best weather weekend of the summer. Lots of sunshine is forecast for both Saturday and Sunday. Saturday highs will be mostly in the 70s with warm spots close to 80. We will wake Saturday morning to morning lows in the mid 50s to lower 60s and Sunday morning lows will be a repeat performance. Sunday highs will be in the upper 70s and lower 80s. Humidity levels will be very low all weekend with not a drop of rain in the forecast.
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MANY THANKS TO TROPICAL TIDBITS FOR THE USE OF MAPS
Please note that with regards to any severe weather, tropical storms, or hurricanes, should a storm be threatening, please consult your local National Weather Service office or your local government officials about what action you should be taking to protect life and property.