Heavy Rain Today/Tonight, Weekend OK

Tropical Storm Andrea made landfall yesterday evening in Dixie County, FL as a 65 mph tropical storm.  She is currently along the South Carolina coast racing towards the Northeast at 28 mph.  Rain is falling throughout much of the northeast as Andrea interacts with a front moving to the North.

NHC Tropical Storm Andrea 5 am advisory

The center of Andrea, which will be transitioning to a nor'easter today, will pass right over Cape Cod or the canal.  The current radar/satellite

NWS Northeast Regional Radar 538 am

GOES_East Water Vapor Satellite 515 am (NOAA)

A conveyor belt of rain is located off the east coast and has its roots deep in the tropics.  Not only that, as the NWS AFD discusses this morning the upper level set up is reminiscent of our winter storms and precipitable water values are running around 2 inches.  This means that the models are probably underdone on their precipitation outputs.  That is an excellent catch by the mets at BOX.

SPC mesoanalysis 5 am Precipitable Water

As the core of Andrea moves up the coast these values will move into Southern New England.  It is for this reason most of the region is under a flood watch, with the exception of the Cape/Islands.  There is a wind advisory for Nantucket as winds will gust as high as 60 mph out there (may be a stretch, certainly 50+)

NWS Boston Advisories 06/07/13

The WPC likes a general 2.5-3+ inches for RI/CT/MA

WPC 1-2 day precipitation totals

Already radar is estimating over an inch of rain in parts of CT.  The heaviest rain is still well to the south

NWS Boston precipitation estimate 6 am

Here is the forecast surface chart tonight around 11 PM

WPC surface forecast Friday 8 pm

Here is one model's simulated radar at 11 PM

06z NAM hires simulated radar 11 PM (image weatherbell)

Now for the winds.  The biggest area of concern is Nantucket and Martha's Vineyard as they will be clearly on the east side of the system where the strongest winds are.  The NHC thinks there is a 40-50 percent chance of tropical storm force winds on the islands

NHC tropical storm force wind probabilities

The strongest winds will not arrive until 10 PM or so.  The strongest will be between 1 AM and 8 AM.  Here are the 900 mb winds at 6 am

06z NAM hires 900 mb winds, mslp 6 am Sat (image weatherbell)

These will need heavy precipitation to bring down the strong winds and that will happen from time to time.  Isolated power outages are likely in SE MA/ Cape and Islands.  The good news is that this system is moving rapidly and will be gone by 9 am tomorrow, perhaps sooner.  Tomorrow afternoon ends up with a few breaks of sun along with the chance for a spot shower or thunderstorm.  Temperatures will climb into the mid 70's

06z NAM hires 2 m temps Sat 5 pm (image weatherbell)

Sunday will be a nice day.  We need to enjoy it as the pattern is very active with only brief dry stretches.  Expect temperatures near 80 with a mix of sun and clouds.  Another round of showers and thunderstorms is likely Monday into Tuesday with the potential for some severe weather.  I'll talk to you later on, have a good Friday despite the rainfall.